THE COMPLEMENTARITY OF FEED
RESOURCES FOR ANIMAL
PRODUCTION IN AFRICA
PROCEEDINGS OF THE JOINT FEED RESOURCES
NETWORKS WORKSHOP HELD IN GABORONE, BOTSWANA
4-6 MARCH 1991
Edited by
John E S Stares
Abdullah N Said
Jackson A Kategile
APRIL 1992
African Feeds Research Network
PO Box 5689, Addis Ababa, Ethiopia
Correct citation: Stares J E S, Said A N and Kategile J A (eds). 1992. The
complementarity offeed resources for animalproduction in
Africa. Proceedings of the joint feed resources networks
workshop held in Gaborone, Botswana, 4-8 March 1991.
African Feeds Research Network. ILCA (International
Livestock Centre for Africa), Addis Ababa. Ethiopia. 430 pp.
THE COMPLEMENTARITY OF FEED
RESOURCES FOR ANIMAL PRODUCTION
IN AFRICA
PROCEEDINGS OF THE JOINT FEED RESOURCES
NETWORKS WORKSHOP HELD IN GABORONE, BOTSWANA
4-8 MARCH 1991
Edited by
John E S Stares
AbduIIah N Said
Jackson A KategiIe
APRIL 1992
AFRICAN FEEDS RESEARCH NETWORK
PO BOX 5689, ADDIS ABARA ptuvw
one 
PW3U-TQ8-JRRJ
ABSTRACT
These are the Proceedings of the last joint workshop of the Pasture Network for
Eastern and Southern Africa (PANESA) and the African Research Network for
Agricultural Byproducts (ARNAB), held in Gaborone, Botswana, 4-8 March
1991. This volume contains the three addresses delivered at the opening session
together with 38 full texts and 12 abstracts of papers presented at the workshop.
The scientific papers are grouped in three sections, corresponding to the main
themes of the workshop. Thus 13 papers and five abstracts address various
aspects of the use of forage legumes in animal nutrition and the nutritive value of
planted and natural pastures; 18 papers and five abstracts deal with animal
production systems based on crop residues and forage legumes; and nine papers
and two abstracts are concerned with institutional and policy issues that affect
integration of feed resource use on-farm.
At the end of the workshop the Steering Committees of PANESA and
ARNAB, together with representatives of the sister network, the West and
Central Africa Forage Network (WECAFNET), and agricultural scientists from
all over Africa, agreed that the three networks should merge to form a unified
network, called the African Feeds Research Network.
KEYWORDS
/Meeting report//feed resources//forages//feed legumes//crop residues//nutritive
value//feed production//farming systems//animal performance//ruminants/
/browse plants/ - /feed treatmenV/supplementary feeding//feed concentrates/
/economic aspects/Zpolicies/
MOTS CLES
IRapport de réunionlIressources alimentaireslIfourrageslIplantes fourragèresl
Irésidus de récoltelIvaleur nutritive/1production alimentairelIsystemes agrairesl
/performances zootechniqueslI ruminantslligneuxfourragerslltraitement des aliments
du bétaillIcomplementation alimentairelIconcentresI/aspects économiqueslIpolitiquesl
ISBN 92-9053-199-1
CONTENTS
Preface ix
Acknowledgements jri
OPENING ADDRESSES
Opening address
The Honourable G M Oteng
Assistant Minister ofAgriculture, Botswana 3
Address
Berhane Kiflewahid
Programme Officer, International Development Research Centre,
Nairobi, Kenya 7
Keynote address
MKyomo
Director, Southern African Centre for Cooperation in Agricultural
Research (SACCAR), Gaborone, Botswana 11
PLANTED AND NATURAL PASTURES:
COMPLEMENTARITY WITH LEGUMES
Complementarity of forages in ruminant digestion: Theoretical
considerations
LRNdlovu 17
Effect of supplementing Chloris gayana hay with three protein sources
on the performance of weaned calves (Abstract)
CELyimo 25
Rumen dry-matter digestive efficiency of camels, cattle, sheep and goats
in a semi-arid environment in eastern Africa
WMigongo-Bake 27
Seasonal changes in livestock diets in a semi-arid environment in
northern Kenya
TRutagwenda andMM Wanyoike 37
in
Performance of associations of Brachiaria ruziziensis with Desmodiwn
intortum, Desmodium uncinatum and Stylosanthes guianensis at
Dschang, Cameroon
R MNjwe, ND Donfack, J Djoukam andHN L Endeley 47
Stylosanthes protein fodder banks for ruminant production in Malawi
(Abstract)
HDCMsiska 53
The value of indigenous browseable tree species in livestock production
in semi-arid communal grazing areas of Zimbabwe
HMSibandaandLRNdlovu 55
Performance of sheep and goats with offspring on semi-arid saltbush
(Atriplex nummulariay-grassland ranges in the early dry season
RCWK6nig,KBecker, RW Benjamin andHSoller 63
Responses to a Pennisetum purpureum (Napier grass) basal diet
harvested at two different heights and fed with three levels of Leucaena
forage to crossbred dairy cows in the subhumid tropics
RWMuinga, W Thorpe, JH Topps andJ G Mureithi 75
Performance and management of sheep on Rhodes grass-stylo pasture
in Nigeria
OSOnifade,IFAduandJOAkinola 85
Effects of environment, botanical composition and nutrition on goat
production on Acacia savannah in Kenya (Abstract)
PNKamau andEKMaranga 95
Etude de 1' influence de quatre fourrages ligneux sur 1' évolution
pondérale des ovins de la race naine de 1' Afrique de 1' Ouest
JKouonmenioc, A Lacoste et H Guérin 97
Effet de la complementation de Panicum maximum avec des fourrages
ligneux sur la croissance et le rendement en carcasse d' ovins Djallonke
males (Resume)
TYo,BJKouao,NCBodjietGTouré Ill
Effet de la complementation d' une ration de base de qualité mediocre
paiAIbizia zygia sur le comportement alimentaire et la croissance
d' ovins Djallonke
D Bouchel, N C Bodji et B JKouao 113
Performance of West African shorthorn cattle grazing under sheanut
trees in the Guinea Savanna zone of Ghana (Abstract)
A K Tuah, K Osei-Amaning, DAdomako andE Boye-Frimpong . . . 127
IV
Intensive fodder gardens for increasing forage availability for
smallholder dairy production in Hai District, Tanzania
EJMtengeti,NAUrioandGIMlay 129
ANIMAL PRODUCTION SYSTEMS BASED ON CROP
RESDDUES AND LEGUMES
Intercrop Stylosanthes effects on millet yields and animal performance
in the Sahel
C Kouamé, S Hoefs, JM Powell, DRoxas and C Renard 137
Effects of feeding hydrated teff straw and protein sources on teff straw
voluntary intake and growth of young horro sheep grazing native
pasture during the dry season (Abstract)
Lemma Gizachew andAlemu Tadesse 147
Sustainable dry-season feeding of ruminants in Ghana: The use of crop
residues and leguminous shrubs as feedstuffs (Abstract)
KAmaning-Kwarteng 149
Colophospermum mopane browse plant and sorghum stover as feed
resources for ruminants during the dry season in Botswana
J Macala, B Sebolai andR R Majinda 151
The use oiLeucaena leucocephala supplementation to improve the
utilisation of maize stover by sheep
A E Kimambo, A MMakiwa andMNShem 163
Browse species and supplements used for feeding small ruminants in
Ogun State, Nigeria
C F I Onwuka, B BA Taiwo and I FAdu 173
Body weight response of West African Dwarf goats fed Gliricidia
sepium, Panicum maximum and cassava (Manihot) peels
OJIfut 181
The feeding value of crop residues from sorghum, pearl and finger
millet cultivars
SNcube and TSmith 189
Non-conventional feed sources as supplements to beef heifers fed low
quality hay (Abstract)
IE JIwuanyanwu, NN Umunna andNIDim 195
Use of whole sunflower seeds and urea as supplements to crop-residue-
based diets for goats
ARWarambwaandLRNdlovu 197
Veld hay as feed for Matebele goats during the last trimester of
pregnancy
L M Sibanda, L RNdlovu andMJ Bryant 205
Fitting forage legumes into the cropping systems of semi-arid Tanzania
MLKusekwa,RSKyamanywaandMDNgowi 215
Effect of grazing hours and concentrate supplementation on milk yield
of crossbred cows under highland conditions in Arsi region, Ethiopia
(Abstract)
Mohammed YKurtu 223
Use of the nylon-bag technique in determining the complementarity of
feedstuffs for dairy cattle rations
A Abate and B Kiflcwahid 225
Crop residues and agro-industrial byproducts in Zambia: Availability,
utilisation and potential value in ruminant nutrition
EMAregheoreandAMChimwano 233
Effect of legume crop residues and concentrate supplementation on
voluntary intake and performance of kirdi sheep fed a basal diet of rice
straw
A TNgwaandCL Tawah 239
The potential of Russian comfrey (Symphytum officinale) as an animal
feedstuff in Uganda
FBBareeba, WOOdwongoandJSMugerwa 249
Complémentation de l' alimentation des ruminants domestiques avec de
la pail le enrichie avec de l' uree a 4% (Resume)
MDoumbia et K Cissoko 257
Effect of addition of concentrates to Sudan grass (Sorghum sudanense)
in the pre-calving period on performance of Holstein-Friesian heifers in
Sudan
AEEl-TayebandAGTakla 259
Caged-layer waste as a nitrogen source in crop-residue utilisation
S B Kayongo, MM Wanyoike, PNNyagah, TE Mailho and
PNMbugua 265
Effects of urea treatment of maize stover and supplementation with
maize bran or urea-molasses block on the performance of growing
steers and heifers
JTKMunthalijCNJayasuriyaandANBhattachrya 279
VI
Effects of undegradable protein supplements on the performance of
weaner steers fed veld hay sprayed with urea
SSibanda,LRNdlovu and TSmith 287
Effects of supplementing a low quality forage with concentrates on
performance and sexual development of dairy heifers
A E El-Tayeb, TA Mohammed, A MHomeida andAA Mohammed . . 299
INTEGRATED FEED RESOURCE USE ON FARM
Prospects for integrating food and feed production in Welayita Sodo,
Ethiopia
Adugna Tolera andANSaid 309
A nutritional and economic evaluation of animal feed self-sufficiency in
Cameroon through integration of forage/crop and livestock production
(Abstract)
R TFomunyam andEN Tambi 319
Feed production and utilisation by dual-purpose goats in smallholder
production systems of western Kenya
K Otieno, JFMOnim andPP Semenye 321
Economic implications of forage innovations on smallholder farms in
western Kenya
FBNyaribo.JFMOnimandDLYoung 339
Effet de la complementation alimentaire sur la production laitiere et la
croissance des bovins a Madagascar (Resume^
JHRasambainarivo 351
Improving milk production in small-scale dairy farms in Botswana:
Incorporating legume fodder in the farming systems
WS Boitumelo andWMahabile 353
Small-ruminant feeding systems for small-scale farmers in humid West
Africa
OBSmith 363
Socio-economic and policy aspects of using crop residues and
agro-industrial byproducts as alternative livestock feed resources in
Nigeria
GBAyoolaandJAAyoade 377
Comparing costs associated with the utilisation of crop residues and
planted pastures in smallholder production systems in the highlands of
Hai District, Tanzania
NSYMdoe,GIMlayandNA Urio 385
vn
Management of the West African dwarf goat in the humid tropics:
A socio-economic appraisal of feeding regimes
Olufemi Oludimu 393
Research priorities for the development of appropriate feeding systems
for dairy production in sub-Saharan Africa
E A Olaloku and S Debre 399
APPENDIX
List of participants 411
via
PREFACE
It is becoming increasingly evident that the future demand for food in
sub-Saharan Africa will far exceed production levels. Already the sub-Saharan
African market for animal products—meat and milk—is largely unsatisfied, and
all forecasts indicate that the present trends towards increases in these markets
will accelerate as human populations grow and urbanisation spreads.
Clearly, livestock production in sub-Saharan Africa needs to be increased
substantially. But animals need to be fed too, and in many parts of the region, for
many months of the year, there is simply not enough feed available. Thus
animals are malnourished, often dramatically so. Hungry animals are
unproductive animals. The problem, therefore, is how to ensure that livestock are
adequately fed all year round.
The problem is not peculiar to sub-Saharan Africa. Seasonal feed shortages
also exist in many other parts of the world: for instance, in the higher latitudes
feed is scarce during the long, harsh winters. But considerable progress in
improving animal nutrition has been made in such countries over the past 20
years. Some examples are the introduction of well-preserved winter silage in
Finland; fodder feed in Denmark; supplemented high-dry-matter silage in The
Netherlands; and preserved clover pastures in New Zealand.
Comparable progress is now urgently needed in sub-Saharan Africa. This
will require excellent national agricultural programmes with well-trained and
dedicated scientists and well-developed research facilities. But success is more
likely to be achieved if the national programmes and scientists cooperate with
each other in working towards common goals—especially in the present climate
of limited resources. Such cooperation is the principal aim of a multidisciplinary
collaborative research network. Three such networks have already been
operating in the area of animal feed resources in Africa: the African Research
Network for Agricultural Byproducts (ARNAB); the Pasture Network for
Eastern and Southern Africa (PANESA); and the West and Central Africa Forage
Network (WECAFNET). However, these three networks had several aims and
activities in common, and it was felt by many network participants that it would
be more efficient to amalgamate them into one pan-African network. This has
now been done, and one of the functions of this workshop was to inaugurate the
African Feeds Research Network.
The other function of the meeting was to provide scientists with an
opportunity to present and discuss their individual research results and activities.
As many of the papers in this Proceedings show, there is now a very
considerable range of options available to the feed resources scientist; a wide
IX
range of forage germplasm, multipurpose trees, fertiliser, irrigation, agricultural
and industrial byproducts, feed processing and conservation techniques, etc. But
there is still much work to be done to alleviate what is the greatest constraint on
animal production in sub-Saharan Africa—nutritional insufficiency.
This workshop was a most important occasion. It represented the start of a
new phase in animal production in sub-Saharan Africa and its effects will, I
believe, be felt for many years to come.
Finally I wish to thank the organising committee for planning the
programme, the Government of Botswana for facilitating the meeting and Dr
Martin Kyomo of SACCAR [Southern African Centre for Cooperation in
Agricultural Research], whose work, over a long period of time, has greatly
facilitated ILCAs development in southern Africa. I wish also to recognise the
commitment of the International Development Research Centre of Canada to
work on feed resources for the past number of years.
John Walsh
Director General
ILCA
ACKNOWLEDGEMENTS
Many people, ILCA staff and others, have made valuable contributions to the
production of these Proceedings. In particular, we wish to thank Yayneabeba
Tadessa, Mekdes Amaha, Genet Delelegn and Serk-Addis Asfaw for typing
manuscripts; Jyl Stares for proofreading typed manuscripts; Sourou Adoutan for
French translation of Abstracts; Tekleab H/Michael for design; Fithamlak Ademe
for drawing the figures; and Mahmoud Saleh and the staff of the ILCA print shop
for printing.
The editors
XI

OPENING ADDRESSES

OPENINGADDRESS
The Honourable G M Oteng
Assistant Minister ofAgriculture, Botswana
Mr Chairman, Director General of ILCA distinguished guests, workshop
participants, ladies and gentlemen.
It is a great honour and pleasure for me to have this opportunity to address
the opening session of this workshop. I extend a warm welcome to those of you
who have come to Botswana to participate in this important meeting and I hope
that your stay here will be enjoyable and productive.
We in Botswana are highly honoured to have been requested to host this
historic workshop. I say historic in the sense that this is the first workshop held
by the African Feeds Research Network. This network is a result of the
collaboration of three institutions; the Pasture Network for Eastern and Southern
Africa (PANESA), the African Research Network for Agricultural Byproducts
(ARNAB) and the West and Central Africa Forage Network (WECAFNET). It is
our hope that your presence here in Botswana, and your deliberations throughout
this week, will be of benefit to our livestock industry which, to a large extent, is
still dependent on natural rangeland.
In sub-Saharan Africa, livestock production is an important component of
the agricultural sector, as evidenced by the large herds and flocks in this region.
Most of the people in our countries continue to depend largely on agriculture for
their livelihood. It is unfortunate that, in most of Africa, the livestock subsector
has remained traditional and largely undeveloped. Management is poor,
reproduction and growth rates are low, there is a high incidence of disease, and
we have very low offtake rates.
The productivity of the livestock sector in our part of the continent has
remained almost static for the past two decades. In fact, some countries have
reported negative trends. Apart from those factors I have already mentioned, this
has mainly been caused by adverse climatic conditions, such as poor rainfall and
droughts, and by increasing populations that have aggravated the over-
exploitation of natural resources, especially land. The uncontrolled population
increase has resulted in serious competition for land, and so less land is available
for agricultural purposes. This has increased the problems of overstocking and
hence of overgrazing of rangelands in most of our countries.
As a result, most of sub-Saharan Africa has, up to now, not been able to
produce sufficient food to feed its people. In the livestock sector we are still net
importers of milk and meat. With the current lack of foreign exchange, most of
our countries cannot afford to import these important commodities, and so our
people are faced with unbalanced diets and, in some cases, not enough food. We
all know, of course, that inadequate diets and poor nutrition, especially of
children, will eventually lead to problems in the development of our manpower
resources.
We need not be reminded that it is our responsibility as nations to feed
ourselves. We cannot blame others for our plight, and neither can we depend
forever on the goodwill of the international community to donate food to feed
our people. Instead, we must strive harder to seek solutions that will reverse the
current trend and indeed improve food security in our respective countries and
the whole region. We should therefore commend those national and regional
organisations which are making efforts to improve livestock production and
arable agriculture in our region.
The International Livestock Centre for Africa (ILCA) has for a long time
been involved in research programmes that seek to improve livestock
productivity. In order to address the requirements of the various types of
livestock, ILCA coordinates several disciplinary networks focusing on, for
example, cattle and small ruminant milk and meat, feed resources and animal
traction. These networks help to streamline research programmes in order to
avoid unnecessary duplication.
Nutrition is one of the major factors that influence an animal' s productivity,
and so we are pleased to note that all the disciplines under ILCA which deal
separately with forages, pastures, crop residues and byproducts have decided to
form one network, the African Feeds Research Network. This network will
endeavour to provide all the information available on livestock feed. We
therefore commend PANESA, ARNAB and WECAFNET for their collaborative
efforts that finally led to the establishment of this unified network.
As I said earlier, the livestock industry in Botswana still largely depends on
natural rangeland. I believe that this is also true for many other countries of
sub-Saharan Africa. Most of our farmers have failed to appreciate the need to
improve pastures and to incorporate pastures and forages, crop residues and
byproducts in their livestock production systems. We need a great deal of
information on types of feed resources which are available, on their suitability
for various ecological zones, on their nutritive value and on how to preserve,
store and utilise them properly. This information will assist us to promote the
production and use of fodder among our livestock owners.
We hope, therefore, that these institutions and networks of ours, and you the
scientists, will work hard to ensure that we have access to all the information we
need. We also hope that there will be increased effort to strengthen national
research institutions in order to develop their capacity to carry out this important
task. In addition, we should pay particular attention to the training and
development of our scientists and researchers, in order to improve their
knowledge and skills.
One way of achieving this is through the promotion of interaction among
you scientists, which will ensure the exchange of ideas and information.
Finally, I wish to take this opportunity to commend ILCAand the various
networks for their efforts in organising this workshop and for deciding to hold it
in Botswana. I hope that your deliberations here will be successful, and will add
to all our efforts to continue to seek solutions to Africa's food problems.
Ladies and gentlemen, it is now my great pleasure to declare this workshop
open, with Botswana's national slogan.
PULA PULA PULA

ADDRESS
Berhane Kiflewahid
Programme Officer
International Development Research Centre
PO Box 62084, Nairobi, Kenya
Mr Chairman, Honourable Minister, ladies and gentlemen.
I am grateful for this opportunity to present a brief overview of the role of
the International Development Research Centre in livestock development in
sub-Saharan Africa
The mission of the International Development Research Centre (IDRC) is to
contribute to development through research and research-supporting activities.
The Centre aims to assist in promoting the indigenously determined social and
economic advancement of trie developing regions of the world, with particular
focus on the poorest people of those regions.
Within this mission, IDRC has two principal objectives: first, to support
research which is directly relevant to Third World development and which has
demonstrable links to the basic needs of the poor; and second, to assist
developing countries to build and strengthen indigenous research and research-
supporting capacity, at the national, but also at the regional, level, and mainly in
terms of human resources. A strong national research capability is essential if the
problems confronting development are to be adequately addressed.
IDRC addresses these objectives by focusing its activities in six main areas:
agriculture, food and nutrition sciences; communications; earth and engineering
sciences; health sciences; information sciences; and social sciences. IDRC also
funds training in all these areas.
Agriculture, food and nutrition
The mission of IDRCs Agriculture, Food and Nutrition Sciences (AFNS)
Division is to ensure access for the individual to food and other basic necessities
through the sustainable use of renewable resources. The Division strives to
achieve stable and sustainable increases in productivity while maintaining
environmental integrity, and to increase income and employment opportunities.
The Division's budget is allocated to support research by scientists working
in their own countries and national institutions. Support is also given to research
by international and regional organisations if they are closely linked to research
activities at the national level through networks such as the African Research
Network for Agricultural Byproducts (ARNAB) and the Pasture Network for
Eastern and Southern Africa (PANESA), both coordinated by the International
Livestock Centre for Africa (ILCA).
The Division also gives high priority to disseminating research results and
training research staff in developing countries. On average, 2-5% of project
funds are allocated to dissemination of research results through publications and
workshops. Most AFNS projects contain a specific training component which,
on average, accounts for 10% of the project budget. Several young African
scientists have been trained at postgraduate level through this support. For
example, three animal scientists from Botswana's Animal Production Research
Unit (APRU) have undertaken postgraduate training at Guelph, Canada. IRDC
hopes that this small contribution is strengthening APRLTs research capacity.
The AFNS Division's support to research is organised under six
programmes and two units:
Animal Production Systems Programme
Crop Production Systems Programme
Fisheries Programme
Forestry Programme
Post-Production Systems Programme
Agricultural Economics Programme
Environment and Sustainable Resources Management Unit
Nutrition Unit
Of these, the Animal Production Systems (APS) Programme is of most
relevance to this workshop. APS Programme activities focus on research into
large and small ruminants, non-ruminants and animal feed resources, with
emphasis on pasture and forage improvement and byproduct utilisation. Priority
is given to research on cattle because of their large numbers in developing
countries and their importance as sources of milk, meat and draught power, but
the Programme is expanding its support to the small-ruminant sector as sheep
and goats are also very important in African pastoral systems and thrive in areas
that are not suitable for cattle, such as the very arid regions and tsetse-infested
areas. APS Programme support is also provided to research on rabbits, pigs and
poultry, which are vital to other farmers in many smallholder systems.
Globally, the strategy and priorities for research support are based on the
farming system practised in the ecological zones identified, as well as on the
potential for impact and use of research results by the beneficiaries. For example,
major APS Programme research support in East and Southern Africa is targeted
on the following zones:
highly populated, high potential, high rainfall highland areas
• subhumid zones in coastal and hinterland areas
• semi-arid areas where livestock are the major source of food and cash income.
In sub-Saharan Africa the major constraint on livestock production is
feeding. Animals subsist mainly on natural pastures which provide abundant
grazing during the rainy season, but quickly mature and dry up with the onset of
the dry season. It is estimated that in smallholder production systems in
sub-Saharan Africa, up to 60% of available feed resources come from crop
residues. However, their nutritive value is not adequate to sustain reasonable
animal production. A great deal of research on animal feed resources is therefore
needed if livestock production in the region is to be improved.
Supporting collaboration through networks
For the past six years IDRC has been collaborating with ILCA in the
organisation and activities of PANESA and ARNAB. The networks have been
successful in bringing together national and international efforts for research on
the production and utilisation of feed resources on small-scale farms. We hope
that the impact of these networks has not ended at the scientist level, but has also
reached the farmers.
In March 1990, the steering committees of PANESAand ARNAB, and of
the West and Central Africa Forage Network (WECAFNET), recommended a
merger of the three networks into one African Feeds Research Network. The
rationale for the merger was the recognition of the complementarity of their
objectives and of the need for collaborative research by national scientists to
ensure the effective use of available feed resources. Thus the general objective of
the unified feed resources network is to support and strengthen the capabilities of
national agricultural research scientists and institutions to conduct research with
forages, crop residues and agro-industrial byproducts as the basis for the
development of sustainable animal production systems. Specifically, the network
aims to:
• promote collaborative research among participating institutions
• promote exchange of information among animal scientists
• train African scientists in applied research techniques
Links will be maintained with at least 10 other "centre" supported projects
in the region and other networks in Latin America.
IDRC will contribute CADS 817 280 to the unified network's collaborative
research programmes over the next three years (1991-93). This is a reflection of
IDRCs commitment to African scientists.
Mr Chairman, Honourable Minister, ladies and gentlemen, thank you for
giving me your attention.
10
KEYNOTEADDRESS
M Kyomo
Director
Southern African Centre for Cooperation in Agricultural Research
(SACCAR)
Private Bag 00108, Gaborone, Botswana
Mr Chairman, Director General of ILCA IDRC Representative, network
members, ladies and gentleman.
On behalf of animal scientists in the Southern African Development
Coordination Conference (SADCQ region, I wish to extend our warmest
welcome to you distinguished animal nutritionists. Gaborone is the headquarters
of SADCC and the home of the region's Agricultural Research and Training
Coordination Centre. We congratulate the organisers of this workshop, especially
the International Livestock Centre for Africa (ILCA), for holding it in a country
which has the highest per capita number of cattle in Africa. In Botswana, cattle,
goats and sheep are marketed in such an organised manner that both small- and
large-scale farmers can benefit from good returns from selling their animals.
The theme of this workshop, The complementarity offeed resources for
animal production in Africa, is very appropriate now. Livestock mean food; and
Africa' s people desperately need more food. Africa has a higher proportion of
undernourished people than any other region in the world, and also the greatest
rate of population growth; so the numbers of hungry people are increasing all the
time. The Food and Agriculture Organization (FAO) of the United Nations
estimates that in 1969-71, 32.6% of Africa's population—86 million
people—were malnourished; by 1983-85 the proportion had risen slightly, to a
little over 35%, but by then the number of hungry people had increased
dramatically, to 142 million! It is true that food production has increased in many
developing countries over the past three decades, but hunger and malnutrition
continue to affect the lives of up to one billion people in the Third World.
The hunger problem cannot be solved merely by better physical distribution
of food from areas with a surplus to those with a deficit. The real problem is the
lack of purchasing power among the poor segments of the communities. A
successful development strategy, therefore, must promote employment and
increases in the purchasing power of the poor through an emphasis on the
production of labour-intensive wage goods, particularly food. Since 1986,
SADCC has adopted an agriculture-oriented strategy which stresses growth in
11
rural labour-intensive sectors as the primary engine of overall economic growth.
The sheer size of the agricultural sector in the region, which employs 40-80% of
the total labour force, shows that technical change in this sector will have
important macro-economic implications. Increased agricultural production not
only increases domestic food supplies but also stimulates further rounds of
employment growth in the service and urban sectors of the economy. Because of
its output and employment linkage effects with the rest of the economy,
agricultural growth helps to improve access to food supplies for both the urban
and rural poor.
It is generally accepted that increased agricultural production is brought
about by improved agricultural technology. Increased agricultural productivity
provides a combination of benefits: increased profits for farmers; increased
demand for labour; and lower consumer prices. Growth of this kind produces a
net increase in national income that serves as an important engine for driving the
rest of the economy. As incomes rise, and as families become more aware of the
need for better nutrition, the relative character of food demand changes. Rising
income causes food demand to shift to more preferred cereals and to highly
income-elastic livestock products. In many African countries these demands
have been met by increasing imports of livestock products; FAO trade figures
show imports rising from USS 43 million in 1960 to USS 113 million in 1970
and then to USS 680 million in 1980. However, because imports have been
draining the scarce foreign exchange reserves of most countries, local production
is now being encouraged.
The performance of the livestock sector in sub-Saharan Africa during the
past two decades has been disappointing; indeed, livestock production has failed
to meet consumption demands. Poor productivity is attributable to several
factors, including inappropriate government policies, tsetse infestation in areas
which would otherwise be ideal for livestock production, and pricing structures
which favour urban consumers to the detriment of the rural producers, hence
discouraging production.
In the past we used to conduct livestock research without paying too much
attention to the needs of the livestock keepers. We neither addressed the issue of
availability of markets for livestock products nor analysed all the other issues on
the demand and supply sides of the equation. Consumers in all the countries of
sub-Saharan Africa now understand the nutritive values of livestock products,
especially to their children. And the farmers are ready to supply the needed
items. However, feed availability seems to be the main bottleneck.
Traditionally, livestock producers, especially the small-scale ones who are
the majority in most countries, were encouraged to provide all their animal feeds
from their own farms. Fodder banks, crop residues, crop byproducts and animal
wastes are examples of what can be produced on the farm. And alley farming
and agroforestry are examples of recent technologies that can be used to produce
animal feeds. But we now know that feeds produced on the farm cannot meet all
the animals' requirements in terms of energy, protein, minerals and vitamins.
12
Some of the deficiencies must be met by feeding supplements which can only be
produced outside the farm. Such supplements are often not available to small
farmers. And even when they are available, they may be too expensive to make
the enterprises profitable.
This workshop is concerned with increasing the productivity of livestock in
sub-Saharan Africa through better feeding. I expect that we will all gain a lot of
information on this vital subject. There are many questions to be asked, and
answered. One might be how we can influence the producers of raw feed
ingredients—cereals, fish meal, agro-industrial byproducts, etc—to produce
these materials in large enough quantities to lower the cost of production and
hence the price which the livestock keeper must pay. Another might concern the
chemical compositions of all types of feeds, including those from rangelands;
such knowledge will be of immense help in formulating guidelines on optimum
feeding and supplementation regimes. And yet another might concern the
availability of animal feeds to the African farmer.
At the 1989 Annual Meeting of the Consultative Group for International
Agricultural Research, the Director General of ILCA stated that one of his
Centre's thrusts would be focusing on the development of animal feed resources.
He pointed out that between 1961 and 1984 about 51% of African byproduct
feedstuffs were exported to developed countries. Although the figure might be
slightly lower now, we need to study the factors which make our countries export
feeds and at the same time import livestock products at a very high cost. Do we
have among ourselves specialists on national and international markets and their
trends? Do we have any influence on policy to stop such exports? In Botswana
most of the livestock byproducts, such as bone and meat meal, are not exported;
they are recycled back into the livestock production systems.
The African smallholder farmer is now ready to help meet the demand foi
more animal products by adopting new technologies for livestock production,
from raising beef and dairy cattle to raising pigs, poultry and small ruminants.
Feed requirements seem to be the greatest bottlenecks in his or her endeavours.
Let us work with him or her on the utilisation of whatever feed resources are
available, and let the knowledge of the nutritive values of individual and
combined feeds be spread around so that livestock productivity may increase.
I wish this workshop every success.
13
14
PLANTED AND NATURAL PASTURES:
COMPLEMENTARITY WITH LEGUMES

COMPLEMENTARITY OF FORAGES IN RUMINANT
DIGESTION: THEORETICAL CONSIDERATIONS
LRNdlovu
Department of Animal Science
University of Zimbabwe
PO Box MP 167, Mount Pleasant, Harare, Zimbabwe
ABSTRACT
Ruminant livestock production in sub-Saharan Africa is based on forages as the
major feed resource. Strategies on the utilisation of these feeds should aim at
establishing an efficient rumen ecosystem in order to maximise fibre digestion
and optimise microbial protein synthesis. An efficient rumen ecosystem requires
fermentable nitrogen and energy sufficient to support the rumen microbial
population. ApH of 6.5-6.8 is optimum and advantage could be taken of fibre
buffering capacities to maintain the pH. Grasses have poor buffering capacities
while legume forages have very good buffering capacities. Legumes appear well
suited as forage supplements to grasses. Some examples of forage
supplementation are reviewed.
RESUME
Complementarite desfourrages dans la digestion chez les ruminants:
considerations theoriques
EnAfrique subsaharienne, I'élevage des ruminants est largement tributaire de la
disponibilité des fourr ages, lesquels constituent les principales ressources
alimentaires du betail. Les stratégies de mise en valeur de ces aliments doivent
viser a etablir dans le rumen des animaux un ecosysteme capable defaciliter la
digestion de la cellulose ainsi que la synthase des prolines microbiennes.
Celui-ci doit contenir suffisamment d'azote disponible et d'energie pour
entretenir laflore microbienne du rumen. Onpeut se servir de lafaculte
stabilisatrice de la cellulose pour maintenir lepH, dont la valeur optimum se
situe entre 6,5 et 6,8. Contrairement aux graminees, les legumineuses
fourragères possèdent d'excellentes capacités stabilisatrices. Elles semblent
particulierement indiquees comme complement de rations de base de graminees.
Quelques exemples de complementation alimentaire de fourrage ont ete analysés.
17
INTRODUCTION
Ruminant livestock production in most of sub-Saharan Africa is based on forages
as the major feed resource. The term forage refers to herbaceous material
including grasses, legumes, browseable trees and fibrous crop byproducts. In
seasonally dry environments, the main limitations to animal production are the
lack of green feed for at least half of the year coupled with the low nutritive
quality of forages during most of the period of active pasture growth (Jones and
Wilson, 1987). The low nutritive quality of the forage during the growth period
is mainly due to environmental stresses such as high temperatures (Van Soest,
1988) and infertile soils (Roberts, 1987).
In recent years there have been several attempts to improve the nutritive
quality of the forage resource base through propagation of species with high
nutritive value (Dzowela, 1988). However, because of limited land, the
quantities of such forages produced are not sufficient on their own to support the
current livestock population. Judicious combinations of these feeds with the
more abundant low quality forages are needed. This paper discusses the
theoretical basis for such combinations.
ANIMAL UTILISATION OF FORAGES
The major determinant of livestock productivity is dry-matter intake which, in
turn, is influenced by the palatability, chemical composition and physical
attributes of the diet, assuming that the livestock are disease-free. The objective
of designing diets must therefore be to optimise animal productivity; feed intake
and animal response are not good indicators of quality. Thus, while laboratory
analyses of the diets are useful, they are not essential to research progress.
Forage-based feeds yield nutrients to the animal mainly through the
processes of fermentative digestion in the rumen. Strategies for the utilisation of
these feeds should therefore aim to establish an efficient rumen ecosystem that
will maximise the digestibility of fibre within the rumen and optimise microbial
protein synthesis. Additional attention needs to be paid to supply of balanced
nutrients post-ruminally, if high productivity is expected.
ESTABLISHMENT OFAN EFFICIENT RUMEN ECOSYSTEM
Microbial considerations
The fermentative digestion of fibre in the rumen is carried out by a mixture of
bacteria (Mackie and White, 1990), protozoa (Demeyer, 1981) and fungi (Akin
and Boraeman, 1990). The role of protozoa has been the subject of great
controversy which is outside the scope of this discussion (Mackie and White,
1990). Rumen microbes require a source of fermentable nitrogen, usually as
18
ammonia although some species require preformed amino acids and peptides
(Russell and Baldwin, 1978). The low nitrogen (N) content of most mature
grasses points to a need to combine them with a forage with a high N content.
The ideal N concentration in the rumen for efficient digestion has been variously
estimated at 50-70 mg/litre (Satter and Slyter, 1974) and at 150-200 mg/litre
(Krebs and Leng, 1984). These levels are not easy to maintain in stall-fed
animals over a 24-hour period, particularly if the feed is mature grass and it is
fed in insufficient quantities. Plant and protein degradation depends on the
physical nature of proteins, their release from plant cells, the concentration of
proteolytic enzymes and the time available for proteolysis. In tropical forages,
more than 20% of plant proteins are present in structures such as the vascular
bundle sheath which are resistant to microbial attack (Egan, 1985). The presence
of tannins in legumes and browse species may also result in binding of proteins
and thus inhibit microbial attack. This may not necessarily have a negative
impact on the animal if the proteins can be released post-ruminally and thus be
available to enzyme digestion (Mueller-Harvey et al, 1988).
Plant considerations
In the presence of adequate rumen N concentrations, microbes will ferment fibre
to obtain energy for growth and synthesis of new cells. The byproducts of such
fermentation include the volatile fatty acids (VFAs) acetate, proprionate and
butyrate which are the main energy nutrients absorbed in the rumen. Degradation
of specialised plant material by microbes varies from tissue to tissue, decreasing
in the order: mesophyll and phloem > epidermis and parenchyma sheath >
sclerenchyma and lignified vascular tissue (Akin, 1982). Tropical grasses have
few mesophyll cells between vascular bundles (as a consequence of adaptation to
a C-4 photosynthesis pathway) and have a high proportion of lignified vascular
tissue. Both factors combine to lower the degradability of these grasses. As plant
cells mature, their cell walls thicken and deposition of hemicellulose and lignin
increases, further reducing degradability. Thus diets based on tropical grasses
should be supplemented with forages high in readily degradable tissues.
In addition to adequate N and energy supplies, rumen microbes require a
stable pH environment (6.5-6.8). Production of VFAs tends to lower the rumen
pH and thus there is a need to buffer the rumen pH to the optimum level of
6.5-6.8. Forages encourage buffering through increased salivation (Van Soest,
1982) and by the buffering capacity and cation exchange of fibre (McBurney et
al, 1986). Tropical grasses and straws have low ion-exchange and buffering
capacities while tropical legumes and citrus have high ion-exchange and
buffering capacities (Van Soest, 1988). Interestingly, in legumes this buffering
capacity is due to the high lignin content of these species. Lignin has been found
to have a high capacity for cation exchange (McBurney et al, 1986). This cation
exchange is also important in mineral nutrition, a component of forage quality
that is usually overlooked.
19
The chemical composition of the fibre is important in providing indications
of fermentation rates. However, interactions between environment and plant
physiology and growth are sufficient to render associations between fibre
components and nutritive value unreliable (Van Soest, 1988). In general, a high
content of neutral detergent fibre and lignin results in lower fibre degradation
compared to a low content of both. Although legumes have more lignin than
grasses they are degraded more, mainly because of their high N content and the
fragility of their cell walls in addition to their good buffering capacities and
higher content of readily degraded specialised tissues of mesophyll and phloem.
Tropical legumes and browse species also contain phenolics, other than
lignin, which limit the digestibility of cell wall carbohydrates and proteins.
Palatability of feeds is also usually affected (Reed et al, 1988). The most
important non-lignin phenolic compounds seem to be tannins. Tannins help to
inhibit attack on lignified tissues by fungi and bacteria (Barry and Blaney, 1987).
Recent research indicates that condensed tannins are more important than
hydrolysable tannins in affecting digestion of feeds (Reed, 1986). Use of
browseable tree species as supplements should be done keeping in mind the
possible negative effects of tannins.
The next section gives a few examples of the application of these principles
in designing forage-based diets for ruminants.
APPLICATION OFTHE THEORETICAL CONCEPT TO PRACTICE
One of the biggest challenges in feeding low quality forages is to increase their
intake in animal diets. Chemical treatments, while successful, present several
practical problems for smallholder agriculture. Addition of higher quality feeds
to a poor-quality basal diet is more practicable. If the addition does not result in
reduced intake of the basal diet, then the added feed is a supplement. If the
addition results in reduced intake of the basal diet but an increase in total intake,
then a substitution effect exists. Since high quality feeds are available in small
quantities, it is preferred to use them as supplements rather than as substitutes.
A classic case of substitution is reported by Njwe and Olubajo (1989) who
fed fresh Guatemala grass (Tripsacum laxum) with various combinations of
cassava flour (up to 200 g/day) and groundnut cake (up to 150 g/day) to West
African Dwarf goats weighing 9-15 kg. Total dry-matter intake increased with
increasing additions of both cassava flour and groundnut cake. Intake of cell
walls, acid detergent fibre and cellulose (all components of the basal diet)
increased. Fresh Guatemala grass had adequate readily degradable carbohydrates
and, having poor buffering capacity, was unlikely to prevent pH falling below
6.2 when supplemented with cassava flour (another source of readily degradable
carbohydrate). Adding a protein source that was low in fibre did not improve
buffering. It is worth noting that animal productivity in terms of liveweight gain
was increased by substituting concentrates for the basal diet. The merits or
demerits of this substitution then depend on the economic returns to the farmer.
20
An example of supplementation is given by Ayoade (1989) who fed maize
bran (up to 200 g/day) to Malawi indigenous goats fed a basal diet of pigeon pea
(Cajanus cajan) pods. Dry-matter intake of the pods was not changed by adding
maize bran but total dry-matter intake, and digestibility of dry matter and organic
matter, increased. Maize bran presumably supplied readily fermentable
carbohydrates which provided energy to the rumen microbes and thus improved
cellulolytic activity. The buffering capacity of pigeon pea pods ensured that
rumen pH was not severely lowered and thus fibre digestion was not negatively
affected.
Nuwanyakpa and Butterworth (1987) found that supplementing a diet of
molasses and teff straw with varying levels of Trifolium hay increased total feed
intake and apparent digestibility of dry matter, neutral detergent fibre and
nitrogen. The results support the hypothesis that legume supplements enhance
intake and digestion in ruminants. More important, they also indicate the value
of forage with readily degradable tissue (Trifolium hay) as a supplement to crop
byproducts with limited readily degradable tissues.
The value of using green forage, particularly leguminous forage, has been
described by Ndlovu and Buchanan-Smith (1985), Dixon and Egan (1987) and
Elliot and McMeniman (1987) based on stall-fed animals. No reports were found
on grazing animals. A possible experiment would involve grazing/browsing on
green forage for a limited time (say 1-2 hours) plus unlimited access to mature
dry hay. Fodder banks could be used for the restricted grazing on green forage.
This area requires further research.
CONCLUSIONS
Livestock productivity from forage-based diets can be improved by making use
of current knowledge on the rumen ecosystem and on the qualities of different
forage species
REFERENCES
Akin D E. 1982. Forage cell wall degradation and p-coumaric, ferulic and sinapic acids.
Agronomy Journal 74:424—428.
Akin D E and Borneman W S. 1990. Role of rumen fungi in fibre degradation. Journal of
Dairy Science 73:3023-3032.
Ayoade J A. 1989. The effect of maize bran on voluntary intake and digestibility of pigeon
pea (Cajanus cajan) pods by goats. In: Said A N and Dzowela B H (eds), Overcoming
constraints to the efficient utilization ofagricultural by-products as animalfeed.
Proceedings of the Fourth Annual Workshop held at the Institute of Animal Research,
Mankon Station, Bamenda, Cameroun, 20-27 October 1987. ARNAB (African
Research Network for Agricultural By-products). ILCA (International Livestock
Centre for Africa), Addis Ababa, Ethiopia. pp. 267-271.
21
Barry T N and Blaney B J. 1987. Secondary compounds of forages. In: Hacker J B and
Temouth J H (eds), The nutrition of herbivores. Academic Press, Sydney, Australia.
pp. 91-119.
Demeyer D 1. 1981. The role of protozoa in fibre digestion. Agriculture and Environment
6:295-337.
Dzowela B H (ed). 1988. African forage plant genetic resources, evaluation offorage
germplasm and extensive livestock production systems. Proceedings of the Third
PANESA Workshop, Arusha, Tanzania, 27-30 April 1987. ILCA (International
Livestock Centre for Africa), Addis Ababa, Ethiopia. 488 pp.
Dixon R M and Egan A R. 1987. Strategies for optimizing use of fibrous crop residues as
animal feeds. In: Dixon R M (ed), Ruminantfeeding systems utilizingfibrous
agricultural residues - 1987. IDP (International Development Programme of
Australian Universities and Colleges Ltd), Canberra, Australia. pp. 11-26.
Egan A R. 1985. Principles of supplementation of poor quality roughages with nitrogen.
In: Dixon R M (ed), Ruminant feeding systems utilizing fibrous agricultural residues -
1985. IDP (International Development Programme of Australian Universities and
Colleges Ltd), Canberra, Australia. pp. 49-58.
Elliot R and McMeniman N P. 1987. Forages as supplements. In: Hacker J B and
Temouth J H (eds), The nutrition of herbivores. Academic Press, Sydney, Australia.
pp. 409-428.
Jones D I H and Wilson A. 1987. Nutritive quality of forages. In: Hacker J B and Temouth
J H (eds), The nutrition ofherbivores. Academic Press, Sydney, Australia. pp. 65-90.
Krebs G and Leng R A. 1984. The effect of supplementation with molasses/urea blocks on
ruminal digestion. Proceedings ofthe Australian Society ofAnimal Production 15:704.
Mackie R I and White B A. 1990. Recent advances in rumen microbial ecology and
metabolism: Potential impact on nutrient output. Journal ofDairy Science
73:2971-2995.
McBurney M I, Allen M S and Van Soest P J. 1986. Praseodymium and copper cation
exchange capacities of neutral detergent fibres relative to composition and
fermentation kinetics. Journal ofthe Science ofFood andAgriculture 37:666-672.
Mueller-Harvey I, McAllan AB, Theodorou M K and Beever D E. 1988. Phenolics in
fibrous crop residues and plants and their effects on the digestion and utilisation of
carbohydrates and proteins in ruminants. In: Reed J D, Capper B S and Neate P J H
(eds), Plant breeding and the nutritive value ofcrop residues. Proceedings of a
workshop held at ILCA Addis Ababa, Ethiopia, 7-10 December 1987. ILCA
(International Livestock Centre for Africa), Addis Ababa, Ethiopia. pp. 97-132.
Ndlovu LR and Buchanan-Smith J G. 1985. Utilization of poor quality roughages by
sheep: Effects of alfalfa supplementation on ruminal parameters, fibre digestion and
rate of passage from the rumen. Canadian Journal ofAnimal Science 65:693—703.
Njwe R M and Olubajo F O. 1989. Evaluation of cassava flour and groundnut cake as
concentrate supplements for West African Dwarf goats. In: Said A N and Dzowela
B H (eds), Overcoming constraints to the efficient utilization ofagricultural by-
22
products as animalfeed. Proceedings of the Fourth Annual Workshop held at the
Institute of Animal Research, Mankon Station, Bamenda, Camcroun, 20-27 October
1987. ARNAB (African Research Network for Agricultural By-products). ILCA
(International Livestock Centre for Africa), Addis Ababa, Ethiopia. pp. 306-323.
Nuwanyakpa M Y and Butterworth M H. 1987. Effects of urea, molasses, molasses-urea,
noug cake and legume hay on the intake and digestibility of teff straw by highland
sheep. In: Little D A and Said AN (eds), Utilization of agricultural byproducts as
livestockfeeds in Africa. Proceedings of a workshop held at Ryall's Hotel, Blantyre,
Malawi, September 1986. ARNAB (African Research Network for Agricultural
By-products). ILCA(International Livestock Centre for Africa), Addis Ababa,
Ethiopia. pp. 87-98.
Reed J D. 1986. Relationships among soluble phenolics, insoluble proanthocyanidins and
fibre in East African browse species. Journal ofRange Management 39:5-7.
Reed J D, Kabede Y and Fussel L K. 1988. Factors affecting the nutritive value of
sorghum and millet crop residues. In: Reed J D, Capper B S and Neate P J H (eds),
Plant breeding and the nutritive value of crop residues. Proceedings of a workshop
held at ILCA Addis Ababa, Ethiopia, 7-10 December 1987. ILCA (International
Livestock Centre for Africa), Addis Ababa, Ethiopia. pp. 233-252.
Roberts B R. 1987. The availability of herbage. In: Hacker J B and Temouth J H (eds),
The nutrition ofherbivores. Academic Press, Sydney, Australia. pp. 47-64.
Russell J B and Baldwin R L. 1978. Substrate preferences in rumen bacteria: Evidence of
catabolite regulatory mechanisms. Applied Environmental Microbiology 36:319-329.
Satter L D and Slyter L L. 1974. Effect of rumen ammonia concentration on rumen
microbial production in vitro. British Journal ofNutrition 34:199-208.
Van Soest P J. 1982. Nutritional ecology ofthe ruminant. O&B Books, Corvallis, Oregon,
USA. 374 pp.
Van Soest P J. 1988. Effect of environment and quality of fibre on the nutritive value of
crop residues. In: Reed J D, Capper B S and Neate P J H (eds), Plant breeding and the
nutritive value of crop residues. Proceedings of a workshop held at ILCA Addis
Ababa, Ethiopia, 7-10 December 1987. ILCA (International Livestock Centre for
Africa), Addis Ababa, Ethiopia. pp. 71-96.
23
24
EFFECT OF SUPPLEMENTING CHLORIS GAYANA HAY WITH
THREE PROTEIN SOURCES ON THE PERFORMANCE OF
WEANED CALVES
CELyimo
Dairy Practical Training Centre
Buhuri
PO Box 1483, Tanga, Tanzania
ABSTRACT
An experiment was conducted to study the effect of kapokseed cake, cottonseed
cake and sunflowerseed cake, fed as protein-source supplements to Chloris
gayana hay, on the performance of weaned calves. Crude-protein intake was
421, 300, 426 and 395 g/day, and metabolisable-energy intake was 35.3, 34.0,
36.6 and 35.4 MJ/day, for kapokseed cake, maize bran, cottonseed cake and
sunflowerseed cake, respectively. Both crude-protein and metabolisable-energy
intake were significantly (P<0.001) different between treatments.
Calves receiving cottonseed cake had significantly (P<0.01) higher growth
rates compared with the other treatments. Growth rates were 630, 490, 720 and
620 g/day for kapokseed cake, maize bran, cottonseed cake and sunflowerseed
cake, respectively. When growth rate was adjusted to constant crude-protein and
metabolisable-energy intake there were no significant differences between
treatments, indicating that the three seed cakes were equally effective in
promoting the growth rate of weaned calves.
RESUME
Effet sur les performances de veaux sevres de la complementation de join de
Chloris gayana avec trois sources de proteines
Une experience a ete effectuee en vue d'etudier I' effet, sur les performances de
veaux sevres, de I'utilisation de tourteaux de kapok, de coton et de tournesol
comme sources de complements proteiques defoin de Chloris gayana. La
consommation de protéines brutes etait de 421, 300, 426 et 395 g par jour et
celle d'energie metabolisable de 35,3, 34,0, 36,6 et 35,4 MJpar jour
respectivement pour le tourteau de kapok, le son de mats, et les tourteaux de
coton et de tournesol. Les differences de consommation de protéines brutes et
25
d'énergie metabolisable etaient significatives (P<0,001). Les taux de croissance
des veaux recevant du tourteau de coton etaient significativement supérieurs
(P<0,01) à ceux des veaux soumis aux autres régimes alimentaires. Les chiffres
enregistrés etaient de 630, 490, 720 et 620 g par jour, respectivement pour le
tourteau de kapok, le son de mais et les tourteaux de coton et de tournesol. Une
fois ces taux corrigés des variations de la consommation de protéines brutes et
d'énergie metabolisable, il n'y avait plus de différence significative entre les
traitements, ce qui signifie que ces trois types de tourteaux se valent en ce qui
concerne la croissance des veaux sevrés.
26
RUMEN DRY-MATTER DIGESTIVE EFFICIENCY OF CAMELS,
CATTLE, SHEEPAND GOATS IN ASEMI-ARID
ENVIRONMENT IN EASTERN AFRICA
WMigongo-Bake
International Centre for Research in Agroforestry (ICRAF)
PO Box 30677, Nairobi, Kenya
ABSTRACT
The degree of degradability and utilisation of forages by ruminants may vary
between forages and between animals, the latter as a result of passage rate and
basal diet. In the semi-arid environment of northern Kenya, the quality of forage
decreases considerably during the dry season, and consequently rumen
dry-matter digestibility (RDMD) of forages by livestock is also reduced. Astudy
comparing RDMD of major forage species by camel, cattle, sheep and goats
showed no significant differences between animal species within seasons, except
for the camel whose RDMD of grass was significantly lower than that for the
other herbivores. Comparisons between seasons showed that RDMD was lowest
in the very dry season in all species. Overall, camels, and to a lesser degree
goats, had superior DMD to sheep and cattle across seasons. The very dry season
(January-March) is the crucial period for a high quality forage supplement
intervention for all livestock species; cattle suffer the most due to their high
reliance on grass, the least nutritive of the forage components during this period.
RESUME
Digestibilité de la matiere seche dans le rumen chez les camélides, lex bavins,
les ovins et les caprins dans la zone semi-aride d'Afrique de I'Est
Chez les ruminants, le degre de degradation et d'utilisation desfourrages
depend du type defourrage. II est en outre fonction de I'espèce animale, compte
tenu notamment de I'importance du rythme de passage des aliments ainsi que
des caractéristiques de la ration de base. Dans la zone semi-aride du
nord-Kenya, les fourrages s' appauvrissent considerablement au cours de la
saison seche, ce qui se traduitpar une baisse de la digestibilité de la matiere
seche dans le rumen des ruminants. Cette etude a ete effectuee pour comparer la
digestibilite de la matiere seche des principales especes fourrageres dans le
27
rumen chez les camélides, les bovins, les ovins et les caprins. Aucune difference
significative n'a eté enregistrée entre les differentes espèces au cours d'une
mime saison, exception fake des camélides chez lesquels la digestibilité des
graminees etait significativement inferieure a celle des autres herbivores. Quelle
que soit I'espèce animale consideree, la digestibilité de la matiere seche etait
minimum au cours de la saison tres seche. Toutes saisons confondues, la
digestibilite de la matiere seche des camélides et, dans une moindre mesure, des
caprins, etait supérieure a celle des ovins et des bovins. Quelle que soit I'espèce
animale consideree, la saison tres seche (Janvier- mars) constitue la période
critique de complementation, les bovins connaissant alors une situation
particulièrement difficile compte term de leur preference marquee pour les
graminées, pluspauvres que les autres espèces fourragères en cette periode de
I'année.
INTRODUCTION
Ruminant animal production contributes substantially to the world's human food
supply, especially in those marginal areas where pastoralism is the order of life.
This is mainly due to the ability of ruminants to convert carbohydrates found in
the fibrous parts of plants to high quality human foods. The nutritive value of
forages for ruminants depends on the ability of rumen microorganisms to break
down the plant cell wall and ferment the carbohydrates (Nelson et al, 1976). The
degree of degradability and utilisation of forages by ruminants varies between
forages (Duble et al, 1971: Utley et al, 1971) and between animals, the latter as a
result of passage rate (Hennessey et al, 1983) and basal diet (Lindberg, 1981;
Weakley et al, 1983). Most researchers employing the nylon-bag technique (van
Dyne, 1962) to study niminant digestion use a specific basal diet so as to
minimise any variations between animals and different trial periods within
animals. However, while the results gained do indicate relative dry-matter
digestibilities (DMD) of forages, they do not represent natural conditions where
the animals are free-ranging and there is variation in basal diets and hence in
DMD efficiencies.
In semi-arid and arid tropical ecosystems, the quality of forages decreases
greatly during the dry season (Migongo-Bake and Hansen, 1987). Since the basal
diet influences DMD in the rumen (Weakley et al, 1983), all herbivores should
perform poorly at this time, but the animals that will perform best will be those
with higher digestive efficiencies. At other times of die year, inherent differences
in diet selection of different herbivore species might lead to variation in basal
diets and hence in the DMD of forages.
The aim of this research was to find out whether, for free-ranging livestock
species, differences in basal diet between species within seasons, and within
species between the green and the dry seasons, led to any significant differences
in DMD efficiencies for given forage species. This would aid in decision making
on when an intervention, such as use of dry-season forage reserve, would be
28
most appropriate. The study was carried out in a semi-arid area of Marsabit
District, Northern Kenya, in 1981/82.
MATERIALS AND METHODS
Animal species
Four castrates, a camel (Cornelius dromedarius), a steer (Bos indicus), a sheep
(Ovis arks) and a goat (Capra hircus) were fitted with rumen cannulae and used
for dry-matter digestion trials using the nylon-bag technique (van Dyne, 1962;
0rskov et al, 1988). Throughout the experimental period, all four individuals
appeared to be as healthy as animals not included in the trial. The experimental
animals grazed on open range every day and were watered at the normal
watering rates for livestock in the region when water is readily available (green
season), namely every seventh day for camels, every third day for sheep and
goats and every other day for cattle.
Forage species selection, collection and preparation
The sources of forages used in the trials included trees/shrubs, sub-shrubs and
grass. The selection was based upon thorough feeding observations (Buechner,
1950) to determine the most preferred species. Species observed to be selected
most by the four herbivores were collected once every month; only parts eaten
were collected. The samples were air-dried at the prevailing daily temperature
(between 20 and 40°C) until no further weight loss was observed. They were
then ground in a Wiley mill through a 1-mm screen and subsamples were used in
the digestion trial. Forage species preferred by one animal species were also used
for digestion trials in the other three species so as to compare the digestive
efficiencies of the four animal species for similar forages in the range. A standard
sample of Chrysanthemum cineariaefolium, a forb, was used as the control
forage in all of the trials.
Nylon-bag degradability trials
The nylon-bag technique is a simple, cheap and direct method of evaluating
feeds, especially where laboratory facilities are not available (0rskov et al,
1980). The method gives a rapid estimate of the disappearance of the tested
feedstuffs in the rumen, and also allows the disappearance of the tested sample to
be studied with respect to time. It is therefore possible to link the degradation of
a feed with its retention time in the rumen (0rskov et al, 1980). However, the
nylon-bag technique only estimates the dry-matter disappearance rate (DMDR)
of feed from the bag; it gives no direct information on the chemical nature or the
nutritive value of the tested feed.
29
The number of bags used in digestion trials is a function of their size and
weight, and different authors have used different numbers in different animal
species (Miles, 1951; Mehrez and 0rskov, 1977; Rutagwenda, 1989). In this
trial, the number of bags and the incubation times used were a compromise
between two factors: a large enough sample for effective analysis; and the
retention of a microbial environment in the rumen that was as normal as possible.
The nylon bags used in this trial were 4 x 7 cm in size. The quality of the
nylon material (50 threads per cm; pores between the threads could not be seen
using 400x magnification) was such that solids could not enter or leave the bag
(Johnson et al, 1982). Samples (2 g) of the forage to be tested and of the control
forage were put into preweighed (nearest 0.01 g) nylon bags; five replicates were
used for each forage. The samples were incubated for 48 hours (Nocek, 1985;
Walli et al, 1988). After incubation the bags were thoroughly washed until the
water coming out of the bag was clear (Mehrez and 0rskov, 1977; Demeyer et
al, 1982, Varga and Hoover, 1983; Fadlalla et al, 1987). After washing, the bags
were squeezed to remove excess water (Playne et al, 1978; Varga and Hoover,
1983) and then air-dried at the prevailing daily temperature (between 20 and
40°C) until no further weight loss was observed. They were then weighed to the
nearest 0.01 g and the weight of the sample determined by subtracting the weight
of the bag.
RESULTS
Seasonal RDMD comparisons between the four herbivore species are shown in
Table 1. There were no differences between the species in RDMD of forages
from trees/shrubs and sub-shrubs. However, camels were significantly inferior
digesters of grasses compared with the other herbivores. The RDMD of the
sheep and steer were affected the 'most across seasons while the goat and the
camel showed least variation. The majority of the significant differences
observed within species were between the second green and the second dry
seasons, the wettest and driest, respectively, of the study period.
DISCUSSION
Average rainfall over the study area during the four seasons of the study period
was:
• first green season (April-June): 76 mm
• first dry season (July-September): 0 mm
• second green season (October-December): 182 mm
• second dry season (January-March): 17 mm
Although there was no rainfall during the first dry season, overcast skies for
most of the period meant that it was less dry, in terms of negative effect on
vegetation, than the second dry season when cloudless skies resulted in more
30
Table 1. Seasonal rumen dry-matter digestive efficiency ofthe camel, steer, goat and sheep in a
semi-arid region ofnorthern Kenya
Dry-matte digestive efficiencies (%)
Second green Second dry
First green season First dry season season season
'frees/shrubs
Mean SD Mean SD Mean SD Mean SD
Camel 76.4 15.0 70.3 9.0 78.1 5.9 63.6 10.0
Steer 76.7 23.7 71.2 18.4 80.9 5.9 61.3 2.8
Goat 76.3 14.7 71.7 6.9 84.0 5.3 54.8 12.2
Sheep 76.7 14.7 60.8 7.4 85.5 4.2 62.9 4.7
Number of plant
species
10 11 12 11
Sub-shrubs
Camel 71.2 14.1 55.7 15.2 69.7 11.0 58.4 11.6
Steer 69.4 15.8 69.8 11.9 76.0 11.3 54.5 9.6
Goat 69.9 17.1 65.0 17.2 77.4 6.7 59.1 9.2
Sheep 64.7 18.1 64.6 14.6 70.4 13.0 60.8 9.0
Number of plant
species
11 11 11 10
Grasses
Camel 54.1 10.8 49.6 3.1 55.4 11.5 49.1 7.2
Steer 74.4 6.6 59.4 7.8 64.4 5.7 60.9 6.6
Goat 71.1 8.7 59.8 0.9 69.0 4.4 59.1 4.1
Sheep 69.8 8.7 65.1 13.1 66.8 5.1 60.5 6.3
Number of plant
species
17 16 17 17
direct radiation and hence greater evapotranspiration. This led to reduced forage
availability and quality through death above-ground of grasses and most
sub-shrub forage species.
Because the study area was in a remote semi-arid region, it was considered
unwise (because of the high risk of wound infection) to fistulate more than one
individual per species until survival and continuous good health of the fistulates
was established. Figroid et al (1972), working with rumen-fisrulated steers, noted
that although some variation was found between steers, it was a small part of the
overall variance in the nylon-bag technique when relative values between
treatments were considered. This suggests that the error introduced into the
digestion trial results through the use of one animal should not be large as long
31
as several replicates are used and the standard deviation of these remains small.
Five replicates per trial were used in this study.
The type of diet consumed by an inoculum donor has been shown to affect
in vitro digestion (van Dyne, 1962). Other research (van Keuren and Heinemann,
1962; Hopson et al, 1963; Neathery, 1969; Weakley et al, 1983) has shown that
in situ digestion of forages is influenced by the type of forage fed to the host
animals. The livestock species observed in this study grazed on a common open
range. RDMD values were not significantly different (P>0.05) between the steer,
sheep and goat within seasons. This suggests that although the diet compositions
of these animals varied, the quality of the diets did not differ much and so the
rumen microbial populations were probably similar, both quantitatively and
qualitatively. Although the camel was not significantly different from the other
species in RDMD values for forages from tree/shrub and sub-shrub components,
its RDMD values for grasses were lower, often significantly so (P<0.05). Maloiy
(1972) reported that camels, which are chiefly browsers, tended to have a lower
dry-matter digestive efficiency than zebu cattle on low quality hay. According to
Hofmann (1973), true ruminant and pseudo-ruminant (eg, camels) browsers have
rumen structural components adapted to a diet that has a high content of cell
solubles but is also high in lignin. The low RDMD efficiency of camels on grass
is probably a result of low populations of cellulolytic microbes in the rumen
since grass forms a minimal part of their diet in this ecosystem. In Somalia,
however, camels' diets consist chiefly of grass (Newman, 1979), and so it would
therefore be worthwhile studying the dry-matter digestive efficiency of grass,
and the composition of rumen microbial populations, of these animals.
Hopson et al (1963) observed that the digestibility of forages in dacron bags
was significantly higher when alfalfa was fed than when grass hays were fed.
Annison and Lewis (1959) noted that a higher quality diet results in a more
dense and vigorous rumen microflora as compared to a low quality diet.
According to Weakley et al (1983) differences among diets in supporting
different rates of in situ dry-matter disappearance are probably due to a
combination of rumen microbial and physical factors that are subject to changes
in the diet. The quality of forages in the semi-arid region of East Africa decreases
rapidly in the dry season. While the observed low quality of grasses results
mostly from low crude-protein levels (Lindberg, 1981; Van Soest, 1982;
Migongo, 1984), that in browse is mostly due to anti-quality factors such as
lignin and tannins (Van Soest, 1982; Reed, 1983).
The observations in this study indicate that when seasons are extremely dry
and forage availability and quality are low, the RDMD values are also very low.
This suggests that there is a limit to the extent that animals can select for a high
quality diet that is scarce and still meet their daily rumen fill. Sheep, like goats,,
have been shown to increase the particle retention time in the reticulorumen
during the dry season, thus allowing lengthy degradation of the forages in their
diet (Rutagwenda, 1989). Camels are mixed feeders but rely mostly on browse.
However, they have been shown to increase their intake of the grass in the dry
32
seasons (Migongo-Bake and Hansen, 1987). Thus camels may be forced to feed
on grasses when they come across small fields of these (as are common in the
area of study) so as to maximise their dietary intake. Therefore, it is the
differences in the seasonal extremes that determine the extremes in forage
availability and possible degree of selection.
CONCLUSIONS
While livestock in open range might select for high quality forage to maintain a
relatively similar basal diet quality from season to season, the extent to which
they can do this and still maximise their intake becomes significantly reduced in
extremely dry seasons when forage biomass and its quality are low. This would
result in a low quality basal diet, a less dense and less vigorous rumen microflora
and hence very low DM digestion such as was observed in the very dry season in
northern Kenya, the area of this study. This study showed that the dry season
(January-March) is the crucial period for high quality forage supplement
intervention for all livestock species, and that cattle suffer the most due to their
high reliance on grass, the least nutritive of the forage components during the
this period. Camels, followed by goats, fare better, in terms of RDMD, than
sheep and cattle, and appear to be better adapted in the utilisation of available
feed resources across seasons.
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35
36
SEASONALCHANGES IN LIVESTOCK DIETS IN A SEMI-ARID
ENVIRONMENT IN NORTHERN KENYA
TRutagwenda andMM Wanyoike
Department of Animal Production
Faculty of Veterinary Medicine
University of Nairobi
PO Box 29053, Nairobi, Kenya
ABSTRACT
Dietary preference studies of indigenous animals in Isiolo District, northern
Kenya, showed that cattle mainly depended on grass and ate fewer plant species
than other livestock species; camels and goats preferred to browse in all seasons;
and sheep selected more grasses in the wet season but consumed more browse in
the dry season. There was a dietary overlap between camels and goats and
between cattle and sheep; the lowest overlap was between cattle and camels.
Dietary overlap between animals generally increased during the dry season. The
different feeding behaviour and variable dietary overlap of different animal
species suggest that a multi-species grazing system might help to stop further
degradation of already degraded areas.
RESUME
Variations saisonnieres de la composition des rations des animaux d'élevage
dns la zone semi-aride dans le nord-Kenya
Il ressort d'etudes effectuées sur les préférences alimentaires des animaux de
race locale dans le district a"Isiolo au nord-Kenya que les bovins préféraient les
graminées et consommaient moins les autres espèces végetales que les autres
espèces d'animaux; quant aux camélidés et aux caprins, leur préférence allait
aux ligneux, quelle que soit la saison; enfin, les ovins préféraient les graminées
pendant I'hivernage et les délaissaient pour les ligneux pendant la saison sèche.
Les camélidés etaient proches des caprins par le goût tandis que les ânes se
rapprochaient plutôt des bovins; les divergences les plus prononcées (moins de
1% du temps consacré à I'alimentation) avaient eté observées entre ces derniers
et les camélides. D'une maniere générale, les préférences des différentes espèces
se rapprochaient au cours de la saison sèche.
37
 Etant donne la diversiti des comportements alimentaires et des
convergences observees entre les diverses especes animales, I'association de
diverses especes vegétales sur les parcours degrades devrait permettre de freiner
cephenomene de degradation.
INTRODUCTION
In many arid and semi-arid areas of the world, uneven rainfall distribution leads
to wide fluctuations in the quantity and quality of forage available to animals. In
northern Kenya, for example, which has a bimodal rainfall pattern with the long
rains in March to May and the short rains in November and December, forage is
plentiful during and immediately after the rainy seasons, but becomes scarce
during the dry season, when some annual forages may disappear altogether
(Herlocker, 1979; Rutagwenda, 1989). Different animals have evolved various
mechanisms for coping with fluctuations in feed quality and availability (Langer,
1988). Some select high-quality plants to feed on (Hofmann, 1973; Kay et al,
1980); others improve the digestion of poor forage by prolonging the retention
time of feed particles in the forestomach (Van Soest, 1982; Van Soest et al,
1988); and some adopt both mechanisms.
This paper describes the diets selected by animals in northern Kenya, and
how different animal species cope with dry seasons in this environment. It also
suggests strategies for feeding animals during dry seasons.
MATERIALS AND METHODS
Study area
The study was carried out at Ngarendare research station in Isiolo District,
Kenya, 310 km north of Nairobi, at an altitude of 1100 m; annual rainfall here
averages 510 mm. The vegetation of the study area is a thorn-bush savanna
dominated by various Comiphora, Grewia and Acacia species. There is also a
sparse cover of annual grasses, herbs and shrubs. Acacia woodlands and dense
bush dominated by Grewia species are found along seasonal water courses, and
perennial grassland is found on the flood plains. Almost 400 different plant
species have been identified in the grazing area of approximately 100 km
(W Schultka, Department of Botany, University of Giessen, Germany, personal
communication).
Experimental animals and their management
The animals used in the study were two breeds of sheep, the Red Masai and the
Somali Blackhead (body weight 19-55 kg); two breeds of goats, the Small East
African and the Galla (body weight 23-47 kg); Small East African zebu cattle
38
(body weight 185-375 kg); and camels (Camelus dromedarius, body weight
350-620 kg). All animals were male castrates.
The animals were herded and watered according to traditional practices in
the area, but were also treated against internal parasites three times a year and
were provided with a mineral lick in the enclosure all the times.
Vegetation biomass estimation
Vegetation biomass in the grazing area was estimated once a month. An area was
selected that appeared to represent the general grazing range, and three 100-m
transects were laid out in three different directions starting from a central point.
Along each transect 1-m quadrats were placed at 10-m intervals and the plant
material in each quadrat was clipped. The clipped vegetation samples were dried
(first in the field and later at 70°C overnight in the laboratory) and the weights
were recorded.
Dietary preference
Feed preferences were assessed by direct observations (Buechner, 1950;
Schwartz, 1988) made every two weeks from 1984 to 1988. Six sheep (three of
each species), six goats (three of each species), six camels and six cattle were
observed for 10 minutes each between 0900 and 1100 hours. The time spent by
each animal feeding on one plant was recorded to the nearest five seconds; the
plant species and the part of the plant eaten were also noted. On each observation
day, samples of the three plants most preferred by the animal were collected for
chemical analysis and nylon-bag degradation studies.
Dietary overlap between animal species was calculated according to
Rutagwenda et al (1990).
Chemical analysis
The 42 plant species most preferred by the animals were chemically analysed.
Altogether 202 samples (34 grasses and 168 dicotyledons) were analysed for
acid detergent fibre (ADF) and acid detergent lignin (ADL) according to Van
Soest (1963; 1982) and Van Soest and Wine (1967). The cellulose content of the
plants was calculated as the difference between the ADF and the ADL contents.
The crude-protein content of the plants was determined by the standard Kjeldahl
procedure.
Degradation of the selected plants (nylon-bag technique)
In the degradation experiments, eight sheep and eight goats (four of each breed),
fitted with rumen fistulae, were used to test 285 samples (76 grasses and 209
39
dicotyledons) of 53 plant species (11 grasses and 42 dicotyledons) using the
nylon-bag technique.
Plant samples collected during the feeding observations were dried at 70°C
for 24 hours and ground in a Wiley mill to pass a through a 2-mm screen; the
samples were tested two weeks after collection from the field. The nylon bags
used measured 15 x 7 cm and were made from a fine grade (pore size 35 u.m) of
nylon material (Linker KG, Kassel, Germany) according to the procedure
described by 0rskov et al (1980). A 5-g sample of ground plant material was
weighed into each bag, the bags were tied with a nylon string, and five bags were
fixed to a nylon washing line. The five bags on one line were introduced into the
rumen at intervals and removed simultaneously (Nocek, 1985) to give incubation
times of 6, 12, 24, 48 and 72 hours for single bags. After the bags were removed
from the rumen they were washed with tap water until the effluent was clear,
dried (first in the field and later at 70°C for 24 hours) and weighed, and the dry
matter disappearance was then calculated.
RESULTS
Vegetation biomass
The vegetation biomass of the herb layer (excluding browse) varied according to
the rainfall pattern, from 2000 kg/ha during the rainy season to as low as 700
kg/ha during the dry season.
Number of plants consumed
Animals spent different times feeding on individual plants. The number of plants
which occupied 90% of the feeding time of the animals, and the proportion of
time spent feeding on dicotyledons (browses), during the dry and wet seasons are
shown in Table 1.
Cattle ate fewer (P<0.001) plants species in both seasons than other animal
species, and fed on fewer (P<0.001) plants during the dry season than during the
wet season. There were no differences in the number of plant species eaten by
sheep, goats or camels.
Cattle spent less time feeding on dicotyledons than other animal species.
Both cattle and sheep spent much more time feeding on dicotyledons in the dry
season than in the wet season. Goats and camels spent most of their feeding time
on these species in all seasons.
Dietary overlap
The time spent by different animal species feeding on similar plants during the
dry and wet seasons is given in Table 2. Camels and cattle had the lowest dietary
40
Table 1. Number ofplants which occupied 90% of the feeding time and time spentfeeding on
dicotyledons
Dry season Wet;season
Number of % of total Number of % of total
Number of plant species time feeding Number of plant species time feeding
Animal observation on observation on
species days Mean SD dicotyledons days Mean SD dicotyledons
Cattle 10 1.8 0.4 17 21 7.3 2.6 28
Sheep 15 26.5 5.1 35 18 26.0 3.2 82
Goats 15 25.8 4.2 86 18 27.0 2.1 84
Camels 6 28.0 5.1 90 28 29.0 3.0 92
overlap in all seasons. Camels and goats, and cattle and sheep, spent about 50%
of their feeding time on similar plants during the dry season. Dietary overlap
tended to increase during the dry season.
Degradability of selected plants
There were no differences between sheep and goats in the dry-matter
disappearance rate (DMDR) of plant samples in the rumen. There were,
however, differences in DMDR between plant species. The 285 plant samples
tested were divided into three groups according to their DMDR at 48 hours:
• Group 1: plants with DMDR less than 50% at 48 hours (low quality)
Group 2: plants with DMDR of 50-70% at 48 hours (medium quality)
• Group 3: plants with DMDR greater than 70% at 48 hours (high quality)
Table 2. Dietary overlap between animal species
Dietary overlap (% of total feeding time)
Dry season Wet season
Animal species Mean SD Mean SD
Camels - cattle 3.3 3.3 8.5 3.3
Camels - sheep 30.5 5.4 14.2 6.9
Camels - goats 47.5 5.4 12.4 4.6
Cattle - sheep 49.6 5.7 20.1 5.9
Cattle - goats 12.6 3.3 23.3 4.0
Sheep - goats 36.6 9.0 43.0 6.7
The number of observations days in the dry and wet seasons, respectively, were: cattle (10,21); sheep
(15,18); goats (15,18); camels (6,28)
41
Table 3. Tune spent feeding on plant species ofthe three quality groups
Animal
Dry season
% of total feeding time
Wet season
species Group 1 Group 2 Group 3 Group 1 Group 2 Group 3
Cattle 90 10 - 60 31 9
Sheep 40 25 35 25 30 45
Goats 15 35 50 7 35 58
Camels 1 49 50 - 45 55
The time spent feeding on plants of different quality groups is shown in
Table 3. Cattle and sheep spent more time feeding on poor quality plants, and
less time on medium and high quality plants, during the dry season than during
the wet season. Cattle never seemed to feed on good quality forage during the
dry season. Goats spent much more time feeding on medium and high quality
plants than on low quality ones during both seasons. Camels never selected a diet
of low quality during the wet season, and spent very little time on such diets in
the dry season. Obviously goats and camels are better able to select higher
quality plants than are cattle and sheep.
DMDR of individual plants
The DMDR of three monocotyledon species collected repeatedly during the dry
and wet seasons were compared (Figure 1). The DMDR was significantly
(P<0.001) higher during the wet season than during the dry season, indicating
that the quality of monocotyledons was lower during the dry season than during
the wet season.
The DMDR of dicotyledons did not differ greatly from season to season
(Table 4).
Chemical analysis of the selected diet
The crude-protein (CP) content of the diet selected by the animals was higher
during the wet season than during the dry season (Table 5). The CP content of
the diets of cattle during the wet season was about twice that during the dry
season. However, the diet of cattle had a lower CP content than that of other
animals during all seasons. For the other animals, CP content of the diets was
already high during the dry season.
The estimated cellulose content of the diets of cattle was high during the dry
season and decreased during the wet season (Table 5). For the other animals
cellulose content was low and did not change much between seasons.
42
Figure 1. Dry-matter disappearance rate ofthree grass species which were selected repeatedly
during wet and dry seasons
Dry-matter
disappearance rate
(% DM)
100i
-o Wet season
-• Dry season
80
60
40
20
0
100
80
60
40
20
0
100
80
60-
40-
20
0
Tetrapogon cenchriformis 
12 24 36 48
Chrysopogon plumulosus
 
12 24 36 48
Incubation time (hours)
60 72
Source: Rutagwenda (1989)
43
Table 4. Dry-mOter disappearance rate (DMDR) (mean ofeight samples) oftwo representative
dicotyledons Vernonia cinerascens and Indigofera spinosa collected during the dry and
wet seasons
Dry-matter disappearance rate (% DM)
Incubation time
Wet season Dry season
(hours Mean SD Mean SD
Vernonia cinerascens
6 59.2 2.7 529 5.5
12 69.3 9.9 70.3 4.6
24 77.7 11.7 76.8 11.7
48 82.1 11.7 81.5 11.7
72 76.9 6.5 76.7 6.6
Indigofera spinosa
6 42.0 3.9 37.7 3.1
12 51.4 5.1 49.7 3.8
24 61.4 8.5 61.4 3.2
48 66.5 6.1 68.5 1.7
72 68.8 4.8 68.3 1.5
Table 5. Crude-protein and cellulose
Crude-protein content
contents ofthe diet
Cellulose content
(% dry matter) (% dry matter)
Animal species Dry season Wet season Dry season Wet season
Cattle 4-5 10-12 37-40 32-36
Sheep 9-11 11-13 20-29 21-25
Goats 11-14 17-22 15-22 16-22
Camels 14-17 18-22 14-22 14-17
DISCUSSION
This study in northern Kenya agrees with reports from other areas (Hoppe et al,
1977; Coppock et al, 1986) that different livestock species select diets of
different compositions. Cattle always prefer grasses (monocotyledons). Sheep
are intermediate feeders; they prefer grasses during the wet season when these
species are of good quality and are available in sufficient quantities, but as the
dry season starts they switch to feeding on dicotyledons. Goats and camels are
mainly browsers, spending over 80% of their feeding time on dicotyledons.
44
Dietary overlap (potential competition between animal species for available
forage) is low between cattle and camels at all times, but high between camels
and goats and between cattle and sheep during the dry season. Dietary overlap
may not be critical during the wet season when forage is abundant, but during
the dry season competition may reach critical proportions if animals depend on
few plant species. These findings suggest a means of improving range
management and reducing pressure on vegetation in overgrazed arid and semi-
arid areas, namely adopting multi-species grazing systems whereby animals with
different feeding strategies are kept together. For example, keeping cattle and
camels together should lead to improved forage utilisation, as cattle would use
grass not used by camels and camels would use browse not used by cattle.
REFERENCES
Buechner H K 1950. life history, ecology and range use of the pronghorn antelope in
Trans-Pecos, Texas. American Midland Naturalist 43:257-354.
Coppock D L, Swift D M and Ellis J E. 1986. Seasonal nutrition characteristics of
livestock diets in a nomadic pastoral ecosystem. Journal ofAppliedEcology
23:585-595.
Heriocker D J. 1979. Vegetation ofSouthern Western Marsabit District, Kenya.
UNESCO-IPAL [United Nations Educational, Scientific and Cultural
Organization-Integrated Project on Arid Lands] Technical Report D-l Nairobi.
UNESCO, Nairobi, Kenya. 25 pp.
Hofmann R R. 1973. The ruminant stomach: Stomach structure andfeeding habits ofEast
African game ruminants. East African Monographs in Biology, Vol 2. East African
Literature Bureau, Nairobi, Kenya. 354 pp.
Hoppe P P, Qvortrup S A and Woodford M H. 1977. Rumen fermentation and food
selection in East African sheep, goats, Thomson's gazelle, Grant's gazelle and impala.
Journal ofAgricultural Science, Cambridge 89:129-135.
Kay R N M, von Engelhardt W and White R G. 1980. The digestive physiology of wild
ruminants. In: Ruckebusch Y and Thivend P (eds), Digestive physiology and
metabolism in ruminants. MTP Press, Lancaster, UK. pp. 743-761.
Langer P. 1988. The mammalian herbivore stomach. Comparative anatomy, function and
evolution. Gustav Fisher, Stuttgart, FR Germany, and New York, USA. pp. 150-195.
Nocek J E 1985. Evaluation of specific variables affecting in situ estimates of ruminal dry
matter and protein digestion. Journal ofAnimal Science 60:1347-1358.
Orskov E R, Hovell F D DeB and Mould F. 1980. The use of the nylon bag technique for
the evaluation of feedstuffs. TropicalAnimal Production 5:195-213.
Rutagwenda T 1989. Adaptation ofsheep and goats to seasonal changes offorage on a
semi-arid thornbush savannah pasture in northern Kenya. PhD Dissertation.
Tierarztliche Hochschukle, Hanover, FR Germany. 131 pp.
45
Rutagwenda T, Lechner-Doll T M, Schwartz H J, Schultka W and von Engelhardt W.
1990. Dietary preference and degradability of forage on a semi-arid thorn bush
savannah by indigenous ruminants, camels and donkeys. Animal Feed Science and
Technology 31:179-192.
Schwartz H J. 1988. Verbesserte Nutzung naturlicher Weiden in den Trockenzonen
Africas durch Besatz mil gemischten Herden. In: Weniger J H (ed), Beispiele
deutscherAgrarforschung in den Tropen und Subtropen. ICT (International Centre for
Tropical Studies), Berlin, FR Germany, pp. 33-44.
Van Soest P J. 1963. Use of detergents in the analysis of fibrous feeds. II. A rapid method
for the determination of fiber and lignin. Journal ofthe Association ofOfficial
Analytical Chemists 46:829-835.
Van Soest P J. 1982. Nutritional ecology ofthe ruminant. O&B Books, Corvallis, Oregon,
USA. 374 pp.
Van Soest P J and Wine G J. 1967. Use of detergents in the analysis of fibrous feeds. IV
Determination of plant-cell-wall constituents. Journal of theAssociation ofOfficial
Analytical Chemists 50:50-55.
Van Soest P J, Sniffen C J and Allen M S. 1988. Ruman dynamics. In: Dobson Aand
Dobson M J (eds), Aspects ofdigestive physiology in ruminants. Comstock Publishing
Associates, Cornell University Press, Ithaca, New York, USA. pp. 21—42.
46
PERFORMANCE OF ASSOCIATIONS OF BRACHIARIA
RUZIZIENSIS WITH DESMODIUMINTORTUM, DESMODIUM
UNCINATUMAND STYLOSANTHES GUIANENSIS AT
DSCHANG, CAMEROON
RMNjwe, ND Donfack, J Djoukam andHNL Endeley
Department of Animal Science
Institut national de développement rural
University Centre of Dschang
BP 222, Dschang, Cameroon
ABSTRACT
The chemical composition, total dry-matter and crude-protein yield, and the
grass/legume ratio, were evaluated in a trial involving Brachiaria ruziziensis
planted alone or in associations with the legumes Desmodium uncinatum, D.
intortum and Stylosanthes guianensis. Plots were cut back after a regrowth
interval of two months. Results indicated significant increases in yields of total
dry matter (388-524%) and crude protein (403-1012%) from grass/legume
treatments over sole plots of B. ruziziensis. The proportion of legume dry matter
in grass/legume mixtures ranged from 25 to 38%. The crude-protein contents of
B. ruziziensis from mixed grass/legume treatments and from sole plots were not
significantly different. Mixtures offi. ruziziensis with D. intortum and£>.
uncinatum were outstanding in total dry-matter and crude-protein yield.
RESUME
Performances de cultures associees de Brachiaria ruziziensis avec
Desmodium intortum, Desmodium uncinatum et Stylosanthes guianensis a
Dschang (Cameroun)
La composition chimique, la teneur en matiere seche, le taux deproteines brutes
et le rapport graminees/legumineuses ont ete determines dans un essai realise
sur Brachiaria ruziziensis en culture pure ou en association avec les
legumineuses Desmodium uncinatum, D. intortum et Stylosanthes guianensis.
L'intervalle entre coupes etait de deux mois. II ressort des resultats enregistres
que les rendements en matiere sèche (entre 388 et 524%) et les taux deprotéines
Al
brutes (entre 403 et 1012%) etaient plus éleves sur les parcelles a association
graminees-legumineuses que sur les parcelles a B. ruziziensis en culture pure.
La part des legumineuses dans la matiere seche des melanges graminees-
legumineuses variait de25 a 38%. La teneur en protéines brutes de B.
ruziziensis n'etait pas significativement differente entre les parcelles de cultures
associees et celles de culture pure. Les rendements en matiere seche el la teneur
en proteines brutes des melanges de B. ruziziensis avec D. intortum el D.
uncinatum etaient exceptionnellement éleves.
INTRODUCTION
The high nitrogen content of leguminous species contributes to improving the
nutritional quality of the diet of grazing ruminants. The presence of legumes in
pasture also increases the nitrogen content of grass species through subterranean
absorption from leguminous roots. Moore (1962) reported that the nitrogen
content of young Cynodon plectostachyus plants increased from 1.8 to 2.4% in
association with Centrosema pubescens while Jones et al (1967) also reported
increases in nitrogen content oiPaspalum plicatulum from 0.8 to 1% and 1.2 to
1.4% when associated with Macroptilium atropurpureum and Lotononia bainesii.
It has also been observed that association of legumes with grass species
tends to increase total dry-matter yield per hectare. Whitney and Green (1969)
reported that association of Digitaria decumbens with Desmodium canum and
Desmodium intortum resulted in dramatic increases in total dry-matter and
crude-protein yields.
The objective of this study was to determine the effect of associating
Brachiaria ruziziensis with Desmodium intortum, D. uncinatum or Stylosanthes
guianensis on total dry-matter and crude-protein yield, grass to legume ratio and
nitrogen content of B. ruziziensis.
MATERIALS AND METHODS
The study was carried out at the University Centre of Dschang, Cameroon
(altitude about 1500 m). Climatic data for Dschang are given in Table 1.
Brachiaria ruziziensis was planted in sole stand or with a legume,
Stylosanthes guianensis, Desmodium intortum or D. uncinatum, in a randomised
complete block design having four treatments and five replicates. The size of
each plot was 6 x 4 m, and all plots were separated by a 1-m wide path.
Drills of B. ruziziensis were alternated with those of leguminous species at a
spacing of 1 m. After planting the plants were allowed to establish and
completely cover the soil surface before data collection commenced. All plots
were cut back and allowed a regrowth period of 60 days before they were
harvested for data collection. The cutting height was 10 cm. Only the central
2 m area was harvested to avoid border effects. After harvest of each plot, the
48
Table 1 . Rainfall and mean temperatures at Dschang, Cameroon (1500 m altitude), 1989
Number of
rainy days
Monthly
rainfall (mm)
Temperatures (°C)
Month Minimum Maximum Average
January 2 9 11.5 27.0 193
February 0 0 13.1 28.6 20.8
March 11 133 15.3 28.4 21.8
April 18 126 16.4 26.7 21.5
May 18 173 16.0 25.7 20.8
June 22 286 15.7 24.8 20.2
July 23 168 15.7 23.4 19.5
August 27 278 15.7 23.7 19.6
September 24 321 15.7 24.9 203
October 20 140 15.5 25.4 20.4
November 6 20 14.7 26.5 20.6
December 1 11 13.7 27.0 203
Total 172 1655
total fresh weight of forage and of the B. ruziziensis and legume fractions were
determined. Samples (500 g) of fresh forage were collected for laboratory
chemical analysis to determine contents of dry matter, ash, crude protein, crude
fibre, ether extracts and nitrogen-free extracts. The data obtained were
statistically analysed using the procedures of Steel and Torie (1980) for analysis
of variance; differences between treatments were determined using the Duncan's
multiple range test.
RESULTS
The effect of associating B. ruziziensis with various legume species on
dry-matter yield is indicated in Table 2. Dry-matter yield ofB. ruziziensis was
significantly (P<0.05) higher in associations with legume species than in sole
plantings. The dry-matter yield ofB. ruziziensis was higher (P<0.05) when
associated with D. uncinatum than with either/). intortum or S. guianensis.
There were differences (P<0.05) in the proportions of the legumes in the
mixtures, S. guianensis being the most abundant.
The presence of legumes in plots plants with B. ruziziensis boosted total
dry-matter production by up to 524%.
Table 3 shows the effect of legumes on total crude-protein yield and crude-
protein content of B. ruziziensis. Total crude-protein yields from grass-legume
49
Table 2. Effect ofassociation o/Brachiaria ruziziensis with legumes species on dry-matter yield
% Increase
Legume in DM yield
Grass DM DM Total DM compared
(kg/ha) % Grass (kg/ha) % Legume (kg/na) to control
Treatment Mean SE Mean SE Mean SE Mean SE Mean SE Mean SE
B. ruziziensis
(control)
B. ruziziensis +
D. intortum
B. ruziziensis +
D. uncinatum
B. ruziziensis +
S. guianensis
1792 221 100 - - 1792 221 -
6918 116 67.6 8.5 3316 96 32.4 6.9 10 234 1956 471 51
8426 894 75.3 11.3 2764 265 24.7 8.6 11190 1221 524 63
5373 769 61.5 5.9 3365 315 38.5 5.9 8 738 999 388 38
mixtures were significantly (P<0.01) higher than from sole grass plots, and plots
with£>. uncinatum yielded significantly (P<0.05) more crude protein than plots
with the other two legumes.
Differences between crude-protein content ofB. ruziziensis from control
plots and from plots with legumes were not significant.
DISCUSSION
The higher total dry-matter and crude-protein yields from mixtures of legumes
with B. ruziziensis than from grass monocultures agree with work by Whitney
and Green (1969) who found similar yield improvements in work on Digitaria
decumbens associated with Desmodium intortum and Desmodium canum. The
increase of crude-protein yield may be attributed to the nitrogen-fixing ability of
legumes, and the effects this has on nitrogen content of associated grass species.
The presence of legumes in pastures has two important beneficial effects.
First, it reduces the need to provide nitrogen supplements to grazing ruminants.
And second, the nitrogen-fixing capacity of legumes in pastures offers a cheaper
alternative to expensive nitrogenous fertilisers. However, the supply of seed
material may constitute an important constraint that needs to be overcome.
Contrary to observations by Moore (1962), Jones et al (1967) and Birch and
Dougall (1967) that the N content of grass increased when planted in association
with legumes, the present study did not find significant differences in N content
ofB. ruziziensis in monoculture or mixed with legumes. This is probably a
reflection of late harvest of forages, at the stage of seeding, when reserves of
nitrogen in roots, stems and leaves have been mobilised for seed production.
Harvesting earlier, especially before flowering, may provide a more meaningful
assessment of the effect of legume mixture on grass nitrogen content.
50
Table 3. Effect ofassociation o/Brachiaria ruziziensis with legumes on the crude-protein content
ofthe grasses and average crude-protein yield ofplots
Crude -protein yield % increase compared
Crude-protein content
otB. ruziziensis
(kg/ha) to control (%)
Treatment Mean SE Mean SE Mean SE
B. ruziziensis (control) 113 17 - 6.30 0.45
B. ruziziensis +
D. intortum
851 250 468 78 5.38 0.41
B. ruziziensis +
D. uncinatum
1166 204 777 103 7.08 1.04
B. ruziziensis +
S. guianensis
754 142 408 88 5.62 0.24
CONCLUSIONS
The contribution of legumes to improving the crude-protein yield of pasture is
evident. This greatly improves the quality and quantity of the ruminant diet
during the dry season when the nutritional quality of grasses is poor. Different
intervals of cutting need to be investigated to determine the optimal time for
harvesting grass-legume mixtures for feeding to ruminant livestock. The
introduction of legumes to pastures and farming systems is one of the cheapest
ways by which the poor countries of the world can sustain soil fertility. This will
obviously have a positive impact on ruminant productivity.
REFERENCES
Birch H F and Dougall H W. 1967. Effect of legume on soil erosion and percentage
nitrogen in grasses. Plant and Soil 27:292- 296.
Jones R J, Davies J G and Whaite R B. 1967. The production and persistence of grazed
irrigated pasture in South Eastern Queensland. Australian Journal ofExperimental
Agriculture and Animal Husbandry 8:117-189.
Moore A W. 1962. The influence of a legume on soil fertility under a grazed tropical
pasture. Empire Journal ofExperimentalAgriculture 30:239—248.
Steel R G D and Torie J H. 1980. Principles andprocedures ofstatistics: A biometrical
approach. 2nd edition. McGraw-Hill, New York, USA. 633 pp.
Whitney A S and Green R E. 1969. Legume contribution to yields and compositions of
Desmodium spp/Pangola grass mixtures. Agronomy Journal 61 :741-745.
51
52
STYLOSANTHES PROTEIN FODDER BANKS FOR RUMINANT
PRODUCTION IN MALAWI
HDCMsiska
Chitedze Agricultural Research Station
PO Box 158, Lilongwe, Malawi
ABSTRACT
Livestock production in Malawi is seriously affected by feed shortages during
the long dry season, at which time growth rates and body weights are reduced.
Also, reproductive activities coincide with low protein supply, as most calves
and kids are dropped during the dry season. Stylosanthes spp, unlike most other
legumes, grow successfully under many ecological conditions, including infertile
acidic soils. Several methods for introducing Stylosanthes spp into natural
pastures have been evaluated with success. With dry-matter yields of more than
5 t/ha, and crude-protein contents of more than 12%, these legumes have shown
potential for arresting body weight changes during the dry seasons. Thus fodder
banks of Stylosanthes spp seem a possible cheap source of supplementary
protein, compared with expensive commercial supplements such as cottonseed,
groundnut and sunflower cakes. The national implications for pasture and soil
stability, increased herd size and the supply of red meat are discussed.
RESUME
Mise en place de banquesfourrageres de Stylosanthes en vue de I'élevage des
ruminants au Malawi
L'élevage est serieusement affectépar les penuries d' aliments du betail que
connait le Malawi au cours de la longue saison seche caracterisee par un
ralentissement de la croissance et une baisse (lupoids des animaux. Resultat de
taux defecondité élevee des femelles, la plupart des veaux et des chevreaux
naissent au cours de la memeperiode. On peut recourir aux banques fourragères
de Stylosanthes pour resoudre leprobleme de I'insujfisance des protéines, lequel
coincide avec une periode de fortes activites reproductrices. En effet, le
Stylosanthes constuue une source bon marche de protéines, comparee aux
tourteaux de coton ou d arachide dont la production est tributaire de la
pluviosité.
53
En outre, contrairement à la plupart des autres legumineuses, Stylosanthes
est adapte à de nombreux environnements, y compris les sols acides pauvres.
Plusieurs méthodes d'introduction de Stylosanthes dans les pâturages naturels
ont éte évaluées avec succès. Des rendements de plus de 5 t/ha et des teneurs en
proteines de plus de 12% ont éte enregistrés et son fourrage permettait aux
animaux d'améliorer leur état physique. Enfin, cette étude a en outre permis
d'évaluer les conséquences, à I'échelle nationale, de I'introduction de
Stylosanthes sur la stabilite des parcours, la taille des troupeaux et l'offre de
viande rouge.
54
THE VALUE OF INDIGENOUS BROWSEABLE TREE SPECIES
IN LIVESTOCK PRODUCTION IN SEMI-ARID COMMUNAL
GRAZING AREAS OF ZIMBABWE
HMSibanda1 andLR Ndlovu2
1 GTZ/ADA-PPU
(German Agency for Technical Cooperation/
Agricultural Development Authority-Provincial Planning Unit)
PO Box 357, Masvingo, Zimbabwe
Department of Animal Science
University of Zimbabwe
PO Box MP 167, Mount Pleasant, Harare, Zimbabwe
ABSTRACT
A study was carried out to evaluate the nutritive value of indigenous browseable
trees and to determine the patterns of utilisation of these trees by cattle and goats
in two semi-arid areas. These trees are of good nutritive value: both leaves and
pods have a high content of crude protein (7-28%) and low to medium content
of neutral detergent fibre (11-64%). Livestock eat leaves in the wet months of
November to February and pods in the dry months of May to September. Tree
species that produce both leaves and pods thus contribute substantially to the
diets of livestock in the areas studied. The results indicate that the current
recommended stocking rates for these areas need to be reappraised as they were
calculated excluding the contribution of trees/browses. More research on the
propagation and utilisation of these species is required.
RESUME
Valeur nutritive des espèces de ligneuxfourragers en animale dans les
pdturages communaux des zones semi-arides du Zimbabwe
Une etude a ete effectuee en vue de determiner la valeur nutritive des espèces de
ligneux fourragers rencontrees dans les deux zones semi-arides du Zimbabwe
ainsi que leur mode a" utilisation par les bovins et les caprins dans ces régions.
Ces ligneux ont une bonne valeur nutritive dans la mesure ou lews feuilles et
55
leurs gousses sont riches en protéines brutes (7-28%) et pauvres ou
moyennement riches en fibres NDF (11-64%). Les animaux consommaient les
feuilles pendant I'hivernage (novembre-fevrier) et les gousses en saison seche
(mai-septembre). Par consequent, les espèces ligneuses produisant a lafois des
feuilles et des gousses entrent pour unepart importante dans I'alimentation des
animaux dans ces regions. Au vu de ces resultats, les charges recommanddes
pour ces zones doivent etre revisees dans la mesure ou elles ont eté calculees
sans tenir compte de I'importance des ligneux et des arbres fourragers dans
I'alimentation des animaux. Des etudes supplementaires s'averent nécessaires
sur la dissemination et I'utilisation de ces espèces vegetales.
INTRODUCTION
The semi-arid communal areas of Zimbabwe, Natural Regions IV and V
(Vincent and Hack, 1960), are characterised by low rainfall and poor sandy soils.
Cropping consistently fails in these areas, and so livestock production is the
dominant agricultural activity. Livestock management is rudimentary and
consists mainly of herding the livestock in the veld. Grass is limited and only
available in the rainy months of December to March. Indigenous browseable
species play an important role in the survival of livestock in these regions,
particularly during those months when grass is unavailable.
However, most research on livestock feeds and feeding in Zimbabwe has
concentrated on cereal crop grains (Topps and Oliver, 1978), agricultural
byproducts (Ndlovu and Manyame, 1988; Smith et al, 1990) and protein
supplementation (Sibanda, 1990), all of which are either unavailable or available
only in very limited quantities in semi-arid areas. Very little is known about the
nutritive value of indigenous browseable tree species. This study therefore aimed
to evaluate the nutritive quality of such trees and to establish patterns of their
utilisation by cattle and goats throughout the year.
MATERIALS AND METHODS
Study sites
The study was carried out at two sites in the Gwanda District of Matebeleland
South Province in Zimbabwe (29°E, 21°S).
Site 1 was Wenlock Communal Area in Natural Region IV, at an altitude of
900-1200 m. Annual rainfall is 450-650 mm; average temperatures are 22-30°C
in summer and 10-16°C in winter. The vegetation of the area is the dry Miombo
woodland (FAO/UNESCO, 1978) and is dominated by Terminalia sericea and
Julbernardia globiflora trees. Other tree species, such as Colophospermum
mopane, Combretum spp, Kirkia acuminata, Sclerocarya caffra and Acacia,
Albizia and Grewia species dominate in the dark gneiss-derived soils.
56
Site 2 was the Gwaranyemba-Gwanda-Dibilishaba Communal Areas in
Natural Region V, at an altitude of 600-900 m. Annual rainfall here ranges from
300 to 500 mm, and average temperatures are 25-34°C in summer and 14-22°C
in winter. The vegetation of the area is the Mopane Tree Savanna, dominated by
Colophospermum mopane on the alkaline soils and Combreium apiculatum,
Kirkia acuniinata, Adonsonia digitaia and Sclerocarya caffra on dolerite-derived
soils. Acacia, Albizia and Grewia species are found on dark gneiss-derived soils
as at Site 1. The only grasses found at both sites are annuals, such as BoscUi,
Aristida and Panicum spp.
In both areas cattle and goats are the dominant livestock species and on
average each farmer owns 10-17 head of cattle and 10-20 goats. The normal
stocking rate is 3-4 ha/tropical livestock unit (TLU: 1 TLU = 250 kg
liveweight), which is considered excessive based on the recommended stocking
rate of 5-6 ha/TLU.
Data collection
A total area coverage approach was used in order to have a spatial representation
of the areas. Key informants, identified among farmers, agricultural extension
workers and part-time farmers, were given formal questionnaires on utilisation
of indigenous tree species. Hand-clipped samples of leaves, twigs and pods of
browseable tree species were collected throughout one calendar year: samples
were analysed for crude protein (CP) and neutral detergent fibre (NDF) using
AOAC (1985) methods. Patterns of utilisation of different parts of browseable
tree species were determined from visual observations by the researchers with
the assistance of the key informants. Distribution (density and occurrence) of the
tree species was assessed in selected representative locations within each site.
RESULTS
Many of the tree species were common to both sites, but site 1 had a higher
overall tree density than site 2 (Table 1). At both sites, leaves were the tree parts
most utilised by livestock.
Chemical analysis of the tree parts eaten by the animals (Table 1) showed
high CP and low to medium NDF contents. In the two species in which leaves
were analysed at different stages, NDF content increased and CP content
decreased with maturity. For A. nilotica and D. cinerea, leaves had a higher CP
and lower NDF content than pods.
Patterns of utilisation of browseable trees by cattle and goats are shown in
Table 2. Cattle fed mainly on leaves between October and January while goats
fed on leaves between December and March. Pods were preferred by both cattle
and goats in the months of June to September. Cattle ate species like C. mopane
and D. cinerea almost all year round while goats mostly ate Acacia spp and D.
57
Table 1. Densities, occurrences and crude protein (CP) and neutral detergent fibre (NDF)
contents (ofthe parts utilised by livestock) ofbrowseable tree species
Approximate tree Occurrence Chemical content
density
(trees/m2)
(fraction of
locations visited)
of parts used
(%)
Species Site 1 Site 2 Site 1 Site 2 Parts used CP NDF
Acacia nilotica 0.2 - 2,4 - Leaves
Pods
11.25
7.31
13.20
33.14
Acacia tortilis 1 2^1 3/4 5/5 Leaves 19.12 -
Afzelia quanzensis - 0.002 - 1,5 Leaves 19.74 50.96
Colophospermum
mopane
3 1 2/4 3/5
Early leaves
Mature leaves
Dry leaves
18.46
15.42
14.86
44.16
47.58
56.90
Combretum apiculatwn 1 0.01 3/4 5,5 Leaves 21.50 18.34
Combretum hereroense 1 0.007 2/4 l/5 Leaves 8.51 19.27
Combretum imberbe - 0.001 - 1,5 Leaves 13.00 28.20
Commiphora africana - 0.003 - 25 Leaves 17.64 -
Dichrostachys cinerea 1 0.01 4,4 3/5
Leaves
Pods
28.54
13.98
45.93
54.54
Grewia hicolor 1 1 3,4 5,5 Leaves 21.12 60.71
Grewiaflavescens - 1 - 1/5 Leaves 11.45 32.40
Kirlua acuminata - 0.003 - 3,5 Leaves 8.11 11.80
Lonchocarpus capassa 0.2 - 14 -
Early leaves
Mature leaves
22.29
12.72
59.08
63.83
Piliostigma thonningii 0.4 - 3 4 - Pods 7.87 55.37
Terminalia sericea 1 - 2/4 - Leaves 9.15 20.23
cinerea all year round. Leaves of Grewia spp were eaten in the wet months of
December and January, while leaves ofA. quanzensis, K. acuminata and P.
thonningii were eaten in the dry months of June to October.
DISCUSSION
Tree density seems to be affected by rainfall; site 2 had a lower tree density than
site 1. While tree density is important in indicating the amount of biomass
available to livestock, CP and NDF contents indicate the quality of the biomass;
in general, feed quality increases as CP content increases and/or NDF content
decreases. On this basis, the Combretum and Acacia species and K. acuminata
are good quality browses. The role of C. apiculatum in livestock production is
limited by its low density. There is a need for research to study the possibility of
58
Table 2. Tree parts eaten by cattle and goats during the year
Cattle
J F M A M J J A S O N D
Acacia nilotica P P P P
Acacia torulis P P P P
Afzelia quanzensis L L L L L
Colophospermum mopane L D D D L L L
Combretum apiculatum L L L L L
Combretum hereoen.se L L L
Combretum imberbe L L
Commiphora africana L L L
Dichrostachys dnerea L L L L P P P P P L
Grewia bicolor L D D D L L
Grewiaflavescens L L
Kirkia acuminata L L L L L L
Lonchocarpus capassa L L
Piliostigma thonningii L L L L
Terminalia sericea L L
Goals
Acacia nilotica L L L P P P P L
Acacia toraUs L L L P P P P L
Dichrostachys cinerea L L L L L P P P P L
P = Pods; L = Leaves; D = Dry leaves and pods
seeding and propagating C. apiculatum. Unavailability notwithstanding, cattle
eat C. apiculatum leaves for five months of the year, indicating that the leaves
are quite palatable to them.
Of the tree species that serve as livestock feed throughout the year, C.
mopane is the most interesting. In October-December, C. mopane produces
reddish brown young leaves that livestock eat avidly, but only after they have
been cut and wilted for a day or two; mature green leaves are not eaten at all.
The dry leaves are often covered with sweet-tasting mucilage, produced by
insects, which apparently enhances their palatability. No information is available
on the chemical composition of the mucilage. Research is needed to establish
optimal utilisation of C. mopane which is highly drought-resistant and has a high
CP and moderate NDF content.
The other tree species eaten by livestock throughout the year is D. cinerea.
Cattle browse on the leaves from December to April, and on pods from May to
59
September. The pods are not processed in any way, and this lack of processing
could reduce their effective utilisation.
Acacia species are thorny and only goats, which have pointed snouts and
mobile lower lips, are able to avoid the thorns and browse on the leaves. Cattle
only eat the pods fromAcacia species.
The abundance of pods in the dry months of June to September partly
accounts for the survival of livestock during this time, even though, according to
official stocking rates, these areas are overstocked. Official stocking rates were
calculated without taking into account the contribution of browseable trees.
It is interesting that cattle at both sites eat tree parts for 10 months of the
year. Bovines, as a species, are grazers, but the cattle indigenous to these areas
have adapted to the shortage of grazing and have become facultative browsers.
There is need for more intensive laboratory evaluation of these browseable
tree species, not only on their CP and NDF contents but also on potential
anti-nutritional factors. At present very little information is available on the
presence of polyphenolics in these species, even though these compounds are
known to affect digestibility and utilisation of forages (Barry and Manley, 1986).
CONCLUSIONS
The results of this study show that browseable trees are highly nutritious and
contribute substantially to the diet of livestock in these communal areas.
However, stocking rates were calculated excluding the contribution of trees.
Incorporating this contribution in the calculations could clear up some of the
contradictions between the people's need for livestock and policy-makers' fears
of environmental degradation if livestock numbers increase.
More research is needed on the propagation of these browseable tree
species and on technologies to increase their productivity and utilisation. The
current trend of introducing non-indigenous tree species at the apparent expense
of the indigenous ones should be re-evaluated.
REFERENCES
AOAC (Association of Official Analytical Chemists). 1985. Official methods ofanalysis.
14th edition. AOAC, Washington, DC, USA. 250 pp.
Barry T N and Manley T R. 1986. Interrelationships between concentrations of total
condensed tannin, free condensed tannin and lignin in Lotus sp and their possible
consequences in ruminant nutrition. Journal ofthe Science ofFood andAgriculture
37:248- 254.
FAO/UNESCO (Food and Agriculture Organization of the United Nations/United Nations
Educational, Scientific and Cultural Organization). 1978. Report on the
agro-ecological zones project. Volume 1. Methodology and results forAfrica. World
Soil Resources Bulletin 48. FAO, Rome, Italy. 168 pp.
60
Ndlovu LR and Manyame Z. 1988. Hydration as a means of improving utilization of
maize stover fed to steers. In: Said A N and Dzowela B H (eds), Overcoming the
constraints to the efficient utilization of agricultural by-products as animal feed.
Proceedings of the Fourth Annual Workshop held at the Institute of Animal Research,
Mankon Station, Bamenda, Cameroun, 20-27 October 1987. ARNAB (African
Research Network for Agricultural By-products). ILCA (International Livestock
Centre for Africa), Addis Ababa, Ethiopia. pp. 343-353.
Sibanda S. 1990. Protein supplementation ofsteers on range. DPhil Thesis. University of
Zimbabwe, Harare, Zimbabwe. 240 pp.
Smith T, Manyuchi B and Mikayiri S. 1990. Legume supplementation of maize stover. In:
Dzowela B H, Said AN, Asrat Wendem-Agenehu and Kategile J A (eds), Utilization
ofresearch results on forage and agricultural by-product materials as animalfeed
resources in Africa. Proceedings of the First Joint Workshop held in Lilongwe,
Malawi, 5-9 December 1988. PANESA/ARNAB (Pasture Network for Eastern and
Southern Africa/African Research Network for Agricultural By-products). ILCA
(International Livestock Centre for Africa), Addis Ababa, Ethiopia. pp. 302-320.
Topps J H and Oliver J. 1978. Animalfoods ofcentral Africa. Rhodesia Agricultural
Journal Technical Handbook No 2. Government Printer, Salisbury, Rhodesia [now
Harare, Zimbabwe]. 122 pp.
Vincent V and Hack H R. I960. Land use and recommendedfarming systems for different
land capability classes in different areas ofSouthern Rhodesia. Annual Conference of
the Professional Officers of the Department of Research and Specialist Services.
Government of Southern Rhodesia, Salisbury, Southern Rhodesia [now Harare,
Zimbabwe]. pp. 16-27. [ILCA library accession (microfiche) number 56017]
61
62
PERFORMANCE OF SHEEPAND GOATS WITH OFFSPRING
ON SEMI-ARID SALTBUSH (ATRIPLEX NUMMULAR1A)-
GRASSLAND RANGES IN THE EARLY DRY SEASON
R C WKonig1, KBecker1, R WBenjamin2 andHSoller1
Institute of Animal Production in the Tropics and Subtropics
University of Hohenheim
7000-Stuttgart 70, Germany
2 Agricultural Research Organization
Volcani Center
50250 Bet Dagan, Israel
ABSTRACT
Fifteen sheep and 15 goats, each suckling a single offspring, were allocated to
three grazing treatments: Atriplex nummularia shrubs plus undisturbed annual
ground vegetation (GV) (Tl: control); Atriplex plus GV reduced by herbicide
spraying (T2); and Atriplex plus reduced GV plus concentrate supplement (T3).
The proportions of GV in the diets were 75% in Tl and 50% in T2 and T3.
Dry-matter intake and free-water consumption were measured over 40 days
together with milk production and changes in liveweight and body solids.
Dry-matter intakes and liveweight changes of ewes plus lambs were 106 g/kg
LW075 and -31 g/day in Tl, 80 g/kg LW075 and -93 g/day in T2 and 78 g/kg
LW^' and -37 e/day in T3: the corresponding values for does plus kids were
104 g/kg LW°-75and +44 g/day in Tl, 88 g/kg LW075 and +34 g/day in T2 and
94 g/kg LVv and +38 g/day in T3. All mothers lost weight and body solids.
Goats drank less water than sheep. The milk production of does was almost three
times that of ewes. Goats tended to utilise Atriplex diets better than sheep.
RESUME
Performances de brebis et de chevres allailantes elevees sur pareours
d 'Atriplex nummularia etd'herbages en zone semi-aride au debut de la
saison seche
15 brebis et 15 chèvres, allaitant chacune un petit, ont ete soumises a I'un des
trois regimes alimentaires suivants: Atriplex nummularia plus de la vegetation
63
naturelle (témoin)(Ti); Atriplex plus de la végetation naturelle en partie detruite
par pulvérisation d'herbicide (T2); et T2plus un complement de concentré (T3).
La végetation naturelle surpied entrait pour 75% dans la ration Ti et pour 50%
dans les rations T2 et T3.
Les consommations de biomasse de matiere sèche (MS) et d'eau ainsi que
les variations du poids vif, du poids sec et de la production de lait ont eté
mesurées sur une période de 40 jours. La consommation de MS et la variation de
poids vif ont été déterminées pour la mère et son petitpris ensemble. A cet effeu
les chiffres enregistrés chez les ovins etaient respectivement de 106 g/kg Pv'
et -31 g/j avec la ration Ti, 80 g/kg PV0'75 et -93 g/j avec T2 et 78 g/kg PV0,75 et
-37 g/j avec T3. En ce qui concerne les caprins, les valeurs correspondantes
etaient respectivement de 104 g/kg Pv' et +44 g/jour avec la ration Ti,
88 g/kgPV0,75 et +34 g/jour avec T2 et 94 g/kgPV0,75 et +38 g/j avec T3. On a
enregistré une baisse du poids vif et du poids sec chez toutes les mères. Quant à
la consommation d'eau, elle variait de 1,3 à 4,5 kg par kilo de MS ingérée et
etait plus élevée chez les ovins que chez les caprins. Les chèvres produisaient
près de trois fois plus de lait que les brebis. Enfin, I'utilisation de ces rations
contenant du fourrage d'Atriplex etait généralement meilleure chez les caprins
que chez les ovins.
INTRODUCTION
Halophytic shrubs of the genus Atriplex, particularly A. nummularia (oldman
saltbush), tolerate high levels of salt in soil and water and resist low and high
environmental temperatures and droughts (Pasternak et al, 1986; Uchiyama,
1987). With its remarkable phytomass production and regrowth after browsing,
and its relatively high crude-protein content and apparent high digestibility
coefficients, this shrub might be a valuable protein supplement to nutrient-
deficient herbage on rangelands and in arid and saline zones.
Results of previous studies on the effect ofAtriplex on livestock
performance have been inconsistent. In some grazing experiments in Australia,
Chile and Israel, no or only temporary advantage could be attributed to the
presence of saltbush (eg, Benjamin, 1980; Benjamin et al, 1986; Leigh, 1986).
Only from South Africa and Libya it is reported that the addition ofAtriplex to
the diet of sheep substantially increased their liveweight (Jacobs and Smit, 1977;
Dumancic et al, 1982).
Goats are reported to be more efficient utilisers of tree and shrub vegetation
than sheep (Merrill and Taylor, 1981) but little information is available on their
performance on Atriplex diets. Goats also appear to drink less water per unit
liveweight than sheep (Ghosh, 1987). This is of interest for management
decisions, as the ingestion of considerable amounts of salt via Atriplex, and the
accompanying increase in water consumption (Wilson, 1966; Arieli et al, 1989),
may restrict the use of this shrub as feed in arid environments.
64
This paper reports on a comparative study of the responses of sheep and
goats to Atriplex diets with varying proportions of ground vegetation or
concentrate supplement. The parameters assessed were liveweight, chemical
body composition, milk production and intake of free water and dry matter.
MATERIALS AND METHODS
The experiment was carried out at the Migda Experimental Station in northern
Negev, Israel (longitude 34° 35' E; latitude 31° 22' N; altitude 100 m) during the
early dry season (24 March to 20 May 1988). The site is situated in a semi-arid
area with a mediterranean type steppe climate and annual rainfall of 270 mm
(SD=70 mm), all of which falls between November and April. In 1983, a 3-ha
field had been planted with A. nummularia shrubs at a density of 1056 shrubs/ha.
In summer 1987 the plantation was grazed until the shrubs were completely
defoliated. They had a good biomass regrowth before the experiment began. The
field was divided into three equal sections, one for each treatment, and each
section was subdivided into two plots, one for sheep and one for goats. Two of
the sections were sprayed with a herbicide to reduce the availability of natural
herbaceous ground vegetation and one was left undisturbed. Ground vegetation
consisted primarily of annual and perennial grasses and a few forbs and thistles.
The experimental animals were German Mutton Merino x Awassi x Finnish
Landrace sheep and Damascus x Local Black Bedouin goats. Fifteen ewes and
15 does, each suckling a single offspring, were selected and, within each species,
were divided into three equal groups by matching for date of parturition and
liveweights of mothers and offspring. The three groups of each species,
consisting of five mothers with their five offspring, were then allocated to one of
the following grazing treatments:
• A. nummularia shrubs and undisturbed ground vegetation without
supplementary feeding (Tl)
• A. nummularia shrubs and reduced ground vegetation without
supplementary feeding (T2)
• A. nummularia shrubs and reduced ground vegetation plus concentrate
supplementation (T3).
Treatment Tl represented good ground vegetation biomass availability after
a winter with high rainfall, while treatments T2 and T3 represented biomass
availability following a drought.
Animals began grazing at about 0800 hours and were corralled at the end of
the day at about 1600 hours, at which time mothers in the T3 groups were
individually fed 300 g pelleted concentrate feed (consisting mainly of maize,
barley grain and soy). The animals changed to the next replicate plot when all
the shrubs in their respective plot were completely defoliated, even if some
ground vegetation still remained. Therefore, the total number of grazing days
was not equal for all treatments. Grazing times on Tl, T2 and T3 were,
respectively, 47, 44 and 44 days for sheep and 47, 44 and 48 days for goats.
65
Before and after grazing in each plot the animals were separated from feed
and water and the adults were injected intramuscularly with about 1 mg tritiated
water (TOH), at the rate of 5 uCi/kg liveweight, four hours after separation; the
exact dosage of TOH was determined by weighing the syringes before and after
the injection. Blood samples (10 ml) were taken from the jugular vein before the
TOH injection and again after a further fast of 12 hours when TOH had
equilibrated. At times of blood sampling all animals were weighed to the nearest
0.5 kg to determine shrunk liveweight.
Plasma was separated by centrifugation and stored at -4°C. Duplicate sub-
samples (100 mg) of plasma per animal were weighed to the nearest milligram
into counting vials. The samples were mixed with 5 ml of Bray's scintillation
fluid and stored in the dark for 24 hours. Samples, and diluted TOH standards,
were counted for radioactivity in a Kontron liquid scintillation counter for three
minutes. The results were corrected for quenching and background activities and
expressed as disintegrations per minute (dpm). When radioactivity of plasma
duplicates differed by more than 5% a new set of duplicates was prepared.
The following formulae were used to calculate body water space labelled by
tritium dilution (TOH space) and body solids:
TOH *nacm (Icrt = (^/mg standard) x (mg TOH injected)
p K 8) (dpm/mgplasma sample) x 1 000 000
Body solids (kg) = liveweight (kg) - TOH space (kg)
The average daily dry-matter intake was calculated from the difference of
estimated biomass of the vegetation components before and after grazing in each
plot. Shrub biomass was estimated by the method of Seligman et al (1986) and
ground vegetation biomass was determined by the calibrated weight estimate
method of Tadmor et al (1975).
Samples of feedstuffs were dried and ground to pass through a 1 -mm
screen. Crude protein (N x 6.25) was determined by the Kjeldahl method and
crude ash was obtained by incinerating at 550°C for four hours. The in vitro
digestibility of feedstuff dry matter was determined by the method of Tilley and
Terry (1963).
Water troughs equipped with swimmer automates supplied groups of
animals separately. The flow of water was measured with an automatic water
meter. Drinking water was available ad libitum, but access to the troughs was
restricted to one hour after grazing commenced in the morning and one hour at
the end of the day.
Daily (24-hour) milk production was estimated four times in each group.
Two methods were used. In one, offspring were separated from their mothers for
12 hours and then weighed on an electronic balance, accurate to 25 g, before and
after suckling. The process was repeated after another 12 hours of separation. In
the second method, mothers were separated from their offspring for 12 hours and
then injected with 5 ml of oxytocin per animal. Afterwards, their udders were
milked out by hand and the amount of milk was measured volumetrically. Total
milk produced per day per mother was calculated by summation.
66
Three-way analyses of variance were carried out for different criteria using
species, treatment and replicate as independent variables. Computations were
done using the statistical package Statview-512.
RESULTS AND DISCUSSION
Nutritive value of feedstuffs
Crude-protein and crude-ash contents and in vitro digestibility ofA. nummularia,
ground vegetation and concentrate feed are summarised in Table 1. (The Atriplex
samples analysed comprised 25% soft terminal twigs and 75% leaves; these were
the proportions of the plant parts seen to be eaten by the animals.) The crude-
protein content ofAtriplex (10.5%) is at the lower end of the expected range
(Beadle et al, 1957; Kandil and El Shaer, 1989). The digestibility ofAtriplex
(73.3%) is, however, slightly higher than expected (Benjamin et al, 1986, 1987a;
Silva-Colomer et al, 1986). The ground vegetation remained green for about 10
days at the beginning of the experiment but then dried out within eight days.
Dry-matter intake
Dry-matter intake was measured for each "production unit" (mother and
offspring) rather than for individual animals. Results are shown in Table 2.
Intakes were highest in Tl, where the high proportion of ground vegetation
in the total diet represented good biomass availability after a winter with high
rainfall. In T2 and T3, where the ground vegetation was artificially limited to
represent a drought year, total intakes decreased but the share ofAtriplex
increased. The intake depression was more pronounced in sheep than in goats.
Feeding the concentrate supplement (T3) increased total intake of goats but
suppressed intake oiAtriplex. In sheep fed the concentrate, total intake decreased
slightly.
Table 1. Crude-protein and crude-ash contents and in vitro dry-matter digestibilities offeedstuffs
In vitro dry-matter
Crude protein
(%)
Crude ash
(%)
digestibility
(%)
Feedstuff Mean SD Mean SD Mean SD
Atriplex nummularia 10.5 1.55 25.2 1.66 73.3 3.51
Ground vegetation
Green 8.9 0.28 9.0 0.77 75.2 0.69
Dry 5.0 1.35 7.5 0.99 44.1 3.89
Concentrate 15.4 0.68 7.7 0.56 81.4 1.21
67
Table 2. Daily dry-matter intakes ofsheep and goats
Ground
Dry-matter intake per production unit
(mother + offspring)
Content in Ilotal diet vegetation
(g/day)
Atriplex
(g/day)(*: l Con
centrate
(g/day)
Total
Ground
vegetation
g/kgLW*75
per day*Treatment Atriplex Mean SD Mean SD g/day
Sheep
Tl 72.6 27.4 2401 238 907 375 0 3308 106.2
T2 51.9 48.1 1248 197 1157 92 0 2405 80.4
T3 43.5 43.6 1018 255 1020 135 300 2338 77.6
Goals
Tl 72.6 27.4 1944 193 734 413 0 2678 104.4
T2 49.7 50.3 1099 231 1113 99 0 2212 88.1
T3 48.9 38.3 1148 110 899 89 300 2347 93.6
* Mean metabolic weight calculated as mean LW° of mother plus mean Lw ' of offspring
Tl = A. nummularia shrubs and undisturbed ground vegetation without supplementary feeding
T2 = A. nummularia shrubs and reduced ground vegetation without supplementary feeding
T3 = A. nummularia shrubs and reduced ground vegetation plus concentrate supplementation
Water intake
Daily free-water intakes of sheep and goats and their offspring are shown in
Table 3. Average absolute water intake remained constant within species,
irrespective of treatment, with goaLs drinking less than sheep. This constancy
does not mean that water intake was unaffected by treatment; the reduced
dry-matter intake, and therefore the reduced water demand, in T2 and T3
obviously just compensated the increased water requirements with enhanced
Atriplex intake. Actually the ratio of water to feed intake rose in T2 and T3.
Sheep were more affected than goats.
With time, and therefore increasing temperatures and decreasing moisture
content of the ground vegetation, water intake increased significantly (P<0.01).
In sheep in T2, for example, the absolute water intake almost trebled, from 3.6 to
9.5 kg. This effect largely masked minor influences from species or treatment.
Other studies of sheep on Atriplex diets have found water-intake values of
1-8 kg/head or 0.5-5.9 kg/kg DMI (Wilson, 1966), 4-8 kg/head (Jacobs and
Smit, 1977) and 7.9 kg/head or 10.3 kg/kg DMI (Arieli et al, 1989). For goats,
values of 03-1.6 kg/head (Hassan et al, 1982) and 3-4 kg/head or 4-6 kg/kg
DMI (Kandil and El Shaer, 1989) are reported. Ghosh (1987) quotes several
sources where goats had lower water requirements than sheep under similar
68
Table 3. Mean daily water intake and ratio ofwater to feed intake ofsheep and goats
Water intake per production unit (mother + offspring)
eg/day
Treatment Mean SD kg/kg DMl'Der day kg/kg
LWa82perdayb
Sheep
T1 6.44 235 1.95 0.16
T2 6.23 1.58 2.56 0.16
T3 6.71 221 2.98 0.17
Goats
Tl 5.27 218 1.94 0.16
T2 5.25 1.46 234 0.16
T3 4.99 214 2.14 0.16
* Total dry-matter intake, including concentrate „
Mean metabolic weight calculated as mean LWT' of mother plus mean Lw ' of offspring
Tl = A. nummularia shrubs and undisturbed ground vegetation without supplementary feeding
T2 = A. nummularia shrubs and reduced ground vegetation without supplementary feeding
T3 = A. nummularia shrubs and reduced ground vegetation plus concentrate supplementation
conditions (values in the ranges 0.09-0.19 kg/kg LW^' in goats and
0.11-0.21 kg/kg LW0'82 in sheep). In the present study water intake on a
metabolic weight basis was not different between sheep and goats but absolute
water intake and the water to feed intake ratio were lower in goats. In general the
values are very comparable to those of Ghosh (1987), although those were not
established on Atriplex diets.
Milk production
Milk production of ewes and does, as determined by two methods, is shown in
Table 4. The two methods did not produce constantly different or similar results,
and neither method could be clearly preferred over the other. Theoretically, the
oxytocin method should give slightly higher values as the residual milk in the
udder, which is not normally released, is included.
Several factors, such as the difference in time between sampling days and
therefore possibly different milk production, and minor technical disturbances
(wind, spillage), made both techniques rather crude and, given the high standard
deviation of the data, it was not possible to quantify the influence of diet
treatment on milk production of ewes or does. However, in both cases the
methodology was good enough to show huge differences in milk production
between ewes and does. On average, kids received almost three times as much
milk as lambs did (618 vs 224 ml) and this difference was clearly reflected in the
higher weight gains of kids compared to lambs.
69
Table 4. Milkproduction ofewes and does, measured by two methods
Milk production (ml/day)
Weighing Oxytocin
Treatment Mean SD Mean SD Average
Ewes
Tl 280 220 116 112 198
T2 170 157 296 234 233
T3 200 160 280 180 240
Does
Tl 860 540 538 98 699
T2 610 417 442 203 526
T3 650 366 610 187 630
Tl = A. nummularia shrubs and undisturbed ground vegetation without supplementary feeding
T2 =A nummularia shrubs and reduced ground vegetation without supplementary feeding
T3 =A nummularia shrubs and reduced ground vegetation plus concentrate supplementation
Liveweights
Mean liveweights and liveweight changes of ewes, lambs, does and kids are
presented in Table 5. Initial liveweights within a class of animal (ewes, lambs,
does, kids) were not significantly different (P>0.05). Between species and
between classes of animals there were significant differences (P<0.05). All
mothers lost weight; all offspring gained weight. On a production unit (mother
plus offspring) basis, sheep lost weight and goats gained weight in all treatments.
Gains of kids tended to decrease on reduced ground vegetation (T2)
compared to Tl, but losses of does remained constant. For sheep, gains of lambs
were constant but ewes lost weight significantly. Compared to T2, concentrate
supplements (T3) improved performance of all classes of animals except does.
Differences between treatments were not significant (P>0.05). Nevertheless,
they seem to be real as they largely correspond to the pattern found in the milk
production and feed intake results.
In a similar trial at the same site in the wet season, lactating ewes lost 147
and 18 g/day at high and low stocking rates, respectively, while their suckling
lambs gained more than 200 g/day. The animals browsed about 700 g DM/day
from shrubs including Atriplex; although little ground vegetation was available
they received 1.5 kg concentrate per ewe (Benjamin et al, 1987b). Compared to
that result, a maximum average loss of 120 g/day per ewe and a gain of 27 g/day
per lamb in T2, where no concentrate was given and ground vegetation was
limited, seems a rather good performance at a low input level. In a study by
Dumancic et al (1982), ewes fed in pens on cut-and-carry A. nummularia or A.
halimus showed liveweight changes of 10 and -27 g/day, respectively.
70
76.4 38.0 20.3 58.3
78.5 38.7 20.2 58.9
75.2 38.0 20.5 58.5
)
-31 -37 81 44
-93 -32 66 34
-37 -40 77 38
Table 5. Mean liveweights and liveweight changes ofewes, lambs, does and kids
Ewes +
Treatment Ewes Lambs lambs Does Kids Does + kids
Liveweight at start of experiment (kg)
Tl 49.3 27.1
T2 51.4 27.1
T3 49.6 25.6
Liveweight change during experiment (g/day)
Tl -57a 26
T2 -120b 27
T3 -80a 43
Within a column and data set, means followed by the same letter, or no letter, do not differ significantly
(P>0.05). Species always differed significantly (P<0.05)
Tl = A. nummulwia shrubs and undisturbed ground vegetation without supplementary feeding
T2 = A. nummularia shrubs and reduced ground vegetation without supplementary feeding
13=A. nummularia shrubs and reduced ground vegetation plus concentrate supplementation
Body solids
Mean body solids and their changes in ewes and does are shown in Table 6. All
mothers lost body solids. Both ewes and does lost more body solids in T2, where
ground vegetation was limited, than they did in Tl. The relationship confirms the
losses in liveweight of these groups. The heavy loss in liveweight of ewes in T3
is not reflected to the same extent by a loss in body solids. It is possible that
ewes profited relatively more from the concentrate supplement than does did.
Table 6. Mean body solids and their changes in ewes and does
Treatment Ewes Does
Body solids at start of experiment (kg)
Tl 14.7a 9.4a
T2 18.0b 11.2b
T3 14.2a 11.4»
Change in body solids during experiment (g/day)
Tl -100a -60a
T2 -175b -98b
_J3 z9c ^94b
Within a column and data set, means followed by the same letter do not differ significantly (P>0.05).
Species always differed significantly (P<0.05)
Tl = A. nummularia shrubs and undisturbed ground vegetation without supplementary feeding
T2 = A. nummularia shrubs and reduced ground vegetation without supplementary feeding
T3 = A. nummularia shrubs and reduced ground vegetation plus concentrate supplementation
71
The absolute values for body solids are probably underestimated as they
were calculated from the TOH dilution space, and the TOH space may
overestimate actual total body water (Panaretto and Till, 1963; Donnelly and
Freer, 1974). A correction factor might be applied but it would affect the results
equally and the relative change would remain the same. The daily losses of body
solids were higher (except for ewes in T3) than the losses in liveweight. This
means that the animals melted down their body fat reserves and incorporated
water to the extent of around 50 g/day. In other studies where Atriplex was a
major part of the diet, both sheep and goats increased the proportion of water in
their bodies (MacFarlane et al, 1967).
CONCLUSIONS
In the early dry season Arrip/ec-grassland pastures can provide enough nutrients
to does and kids for combined net weight gain, but not to ewes and lambs.
Hence, goats tend to utilise Atriplex diets better than sheep do.
Goats tend to drink less water than sheep, and to have a lower water to feed
intake ratio, when fed Atriplex diets, although their milk production is higher
than that of sheep.
Even small amounts of concentrate improve the performance of mothers
and offspring fed diets containing about 50% Atriplex.
REFERENCES
Arieli A, Nairn E, Benjamin R W and Pasternak D. 1989. The effect of feeding saltbush
and sodium chloride on energy metabolism in sheep. Animal Production 49:451-457.
Beadle N C W, Whailey R D B and Gibson J B. 1957. Studies in halophytes. 2. Analytic
data on the mineral constituents of three species ofAtriplex and their accompanying
soils in Australia. Ecology 38:340-344.
Benjamin R W. 1980. The use of forage shrubs in the Norte Chico region of Chile. In: le
Houeiou H N (ed), Browse in Africa. The current state ofknowledge. ILCA
(International Livestock Centre for Africa), Addis Ababa, Ethiopia, pp. 299-302.
Benjamin R W, Barkai D, Lavie Y and Forti M. 1986. Summer grazing of a 18-month old
plantation of fodder shrubs by weaned ewe lambs. In: Dovrat A (ed), Fodder
production and its utilization by small ruminants in arid regions. Fourth Annual
Report No BGUN-ARI-61-86. Institute for Applied Research, Ben Gurion University
of the Negev, Beer-Sheva, Israel, pp. 8-27.
Benjamin R W, Oren E and Katz E. 1987a. Apparent digestibility ofAtriplex barclayana
and the nitrogen balance of sheep consuming it. In: Benjamin R W, Seligman N G,
Forti M and Becker K (eds), Analysis ofanimal nutrition in shrub-grassland grazing
systems with special reference to semi-aridAfrica. Report No BGUN-ARI-41-87.
Institute for Applied Research, Ben Gurion University of the Negev, Beer-Sheva,
Israel, pp. 7-35.
72
Benjamin R W, Barkai D, Lavie Y and Forti M. 1987b. Winter grazing of a fodder shrub
component within sheep production systems. In: Dovrat A(ed), Fodderproduction
and its utilization by small ruminants in arid regions. Fifth Annual Report No BGUN-
ARI-48-87. Institute for Applied Research, Ben Gurion University of the Negev,
Beer-Sheva, Israel, pp. 5-20.
Donnelly J R and Freer M. 1974. Prediction of body composition in live sheep. Australian
Journal ofAgricultural Research 25:825-834.
Dumancic D, Eskileh M and le Houerou H N. 1982. Study on fodder shrubs consumption
by sheep in Wishtata range development project. Report No LIB 18. FAO (Food and
Agriculture Organization of the United Nations), Rome, Italy. 11 pp.
Ghosh T K. 1987. Water requirements and water feeding strategies in goats. In: Santana
O D, da Silva A G and Foote W C (eds), Proceedings ofthe 4th International
Conference on Goats, 8-13 March 1987, Brasilia. Departamento de Difusao de
Technologia, Brasilia, Brazil. pp. 1267-1274.
Hassan N I, El-Shaer H M and Kandil H M. 1982. Lamb performance on pasture
supplemented with concentrates. World Review ofAnimalProduction 18(4):37-40.
Jacobs G Aand Smit C J. 1977. Benutting von vier Afnp/er-spesies deur skape.
Agroanimalia 9:37—43.
Kandil H M and El Shaer H M. 1989. The utilization ofAtriplex nummularia by goats and
sheep in Sinai. In: Galal E S E, Aboul-Ela M B and Shafie M M (eds), Ruminant
production in the dry subtropics: Constraints andpotential. Proceedings, International
Symposium, 5-7 November 1988, Cairo, Egypt. EAAP [European Association for
Animal Production] Publication No 38. Centre for Agricultural Publishing and
Documentation (Pudoc), Wageningen, The Netherlands, pp. 71-73.
Leigh J H. 1986. Forage value and utilization of Chenopod dominated shrubland.
Reclamation and Revegetation Research 5 :387-402.
MacFarlane W V, Howard B and Siebert B D. 1967. Water metabolism of Merino and
Border Leicester sheep grazing saltbush. Journal ofAgricultural Research
18:947-985.
Merrill L B and Taylor C A 1981. Diet selection, grazing habits, and the place of goats in
range management. In: Gall C (ed), Goatproduction. Academic Press, London, UK.
pp. 233-252.
Panaretto B Aand Till A R. 1963. The composition of mature goats and its relationship to
the antipyrine, tritiated water and N-acetyl-4-amino antipyrine spaces. Australian
Journal ofAgricultural Research 14:926-943.
Pasternak D, Aronson J A Ben-Dov J, Forti M, Mendlinger S, Nerd Aand Sitton D. 1986.
Development of new arid zone crops for the Negev of Israel. Journal ofArid
Environments 11:37-59.
Silva-Colomer J, Fonolla J, Raggi L A and Boza J. 1986. Valoracion nutritiva del Atriplex
nummularia en ganado caprina. RevistaArgentina de Producion Animal
6(ll-12):661-665.
73
Seligman N G, Benjamin R W, Lavie Y, Forti M and Mills D. 1986. Estimation of the
standing biomass of fodder shrubs under grazing conditions. In: Dovrat A(ed),
Fodderproduction and its utilization by small ruminants in arid regions. Fourth
Annual Report No BGUN-ARI-61-86. Institute for Applied Research, Ben Gurion
University of the Negev, Beer-Sheva, Israel, pp. 46-58.
Tadmor N H, Brieghet A Noy-Meir J, Benjamin R W and Eyal E. 1975. An evaluation of
the calibrated weight-estimate method for measuring production in annual vegetation.
Journal ofRange Management 28:65-69.
Tilley J M Aand Terry R A. 1963. A two-stage technique for the in vitro digestion of
forage crops. Journal ofthe British Grassland Society 18:104-111.
Uchiyama Y. 1987. Salt tolerance of Atriplex nummularia. Technical Bulletin of the
Tropical Agricultural Research Center No 22. Tropical Agricultural Research Center,
Yatabe, Tsukuba, Ibaraki, Japan, 69 pp.
Wilson AD. 1966. The intake and excretion of sodium by sheep fed on species ofAtriplex
(saltbush) and Kochia (bluebush). Australian Journal ofAgricultural Research
17:155-163.
74
RESPONSES TO APENNISETUMPURPUREUM (NAPIER
GRASS) BASALDIET HARVESTED ATTWO DIFFERENT
HEIGHTS AND FED WITH THREE LEVELS OF
LEUCAENA FORAGE TO CROSSBRED DAIRY COWS IN THE
SUBHUMID TROPICS
R WMuinga1, W Thorpe2, J H Topps3 andJ G Mureithi1
Kenya Agricultural Research Institute (KARI)
PO Box 16, Kikambala, Kenya
International Livestock Centre for Africa (ILCA)
PO Box 80147, Mombasa, Kenya
School of Agriculture
581 King Street, Aberdeen, Scotland, UK
ABSTRACT
Smallholder dairy production based on zero-grazed Napier grass (Pennisetum
purpureum cv Bana) fed to crossbred Bos taurus x Bos indicus cows has been
introduced to tropical subhumid East Africa. Leucaena leucocephala forage
offers a cheap, convenient source of supplementary protein. Thirty-six Ayrshire/
Brown Swiss x Sahiwal cows with one to four previous lactations and which
calved during the period 26 March to 2 August 1990 were stall-fed individually
to evaluate the effects of harvesting height of Napier grass (1.0 or 1.5 m) and
level oiLeucaena supplement (0, 4 or 8 kg fresh weight) on dry-matter (DM)
intake of Napier grass, total DM intake, liveweight change and milk yield. The
study began on day 15 of lactation and lasted 98 days. Average daily milk yield
and liveweight during the second week of lactation were covariates for milk
yield, and for DM intake and liveweight change, respectively. Harvesting height
of Napier grass significantly (P<0.001) affected Napier fodder and total DM
intakes, liveweight losses and average daily milk yield. Supplementation with
Leucaena tended to increase Napier fodder intake, significantly (P<0.001)
increased total DM intake and reduced liveweight loss, and increased (P<0.05)
milk yield. The results indicate the importance of stage of harvesting of Napier
fodder and the benefits from Leucaena supplementation in attaining an
acceptable level of performance from crossbred dairy cows in the subhumid
tropics.
75
RESUME
Effet sur des vaches laitieres métisses d'un aliment de base de Pennisetum
purpureum (herbe à éléphant) récolté à deux hauteurs de coupe complementé
avec trois niveaux defourrage de Leucaena
L'alimentation à l'auge de vaches métisses Bos taurus x Bos indicus avec des
rations de base composées d'herbe à élephant (Pennisetum purpureum.) a éte
récemment introduite dans les petites exploitations laitieres de la zone tropicale
subhumide de l'Afrique de I'Est. Lesfourrages de Leucaena leucocephala
constituent une source bon marché de complémentation proteique. 36 vaches
Ayrshire/Brown Swiss x Sahiwal qui avaient connu de une à quatre lactations
dans le passé et avaient vile entre le 26 mars et le 2 août 1990 avaient éte
individuellement alimenties à l'auge en vue d'évaluer l'effet de la hauteur de
coupe de l'herbe à élephant (1 m et 1,5 m) et du niveau de complementation de
Leucaena (0,4 et 8 kg defourrage) sur la consommation de matiere seche de
Pennisetum, la consommation totale de matiere seche, les variations depoids vif
et la production de lait. L'expérience a demarré au 15e jour de lactation et a
duré 98jours. La production moyenne de lait par jour et le poids vif enregistrés
au cours de la deuxième semaine de lactation étaient les covariables
respectivement de la production de lait d'unepart et de la consommation de
matière seche et des variations du poids vifde I'autre. La hauteur de coupe avait
un effet significatif(P<0,001) sur la consommation de matiere seche totale et de
matiere seche d'herbe à élephant. L'apport de Leucaena se traduisaitpar un
accroissement de la consommation d'herbe à élephant, une augmentation
significative (P<0,001) de la consommation totale de matiere seche, une baisse
significative (P<0,001) despertes de poids et un accroissement (P<0,05) de la
production de lait. Ces résultats font ressortir I'importance du stade de coupe de
l'herbe à élephant et les avantages d'une complémentation de Leucaena pour les
performances des vaches laitieres métisses en zone tropicale subhumide.
INTRODUCTION
Amajor constraint on dairy development in coastal subhumid Kenya is the
inadequacy of feed resources available on the mixed crop-livestock smallholder
farms targeted in the Ministry of Livestock Development's National Dairy
Development Programme (NDDP). Soils are free-draining and low in organic
matter and fertility, factors which limit the productivity of forages.
Natural pasture is scarce and of poor quality, and its availability in the
future may be further restricted by subdivisions of farms into smaller units. Land
tenure is freehold. Significant quantities of crop byproducts, with the exception
of copra cake and maize bran, are not available. Cash shortages often limit the
purchase of these concentrates by smallholder farmers.
76
To address these problems the Kenya Agricultural Research Institute and
the International Livestock Centre for Africa carry out collaborative research on
feed resources at the Regional Research Centre, Mtwapa, near Mombasa. The
research focuses on developing systems with minimal purchased inputs which
can intensify and sustain the production and utilisation of forages. The zero-
grazing package extended by the NDDP to smallholders is the target, and the
objective is to have profitable milk production through producing, on-farm,
adequate quantities of good quality dry matter for feeding throughout the year.
A review of past on-station forage research at the coast indicated the
potential of Napier grass (Pennisetum purpureum cv Bana), the legume shrub
Leucaena and some herbaceous legumes. Experiences with these forages on
farms supported by the NDDP, and the absence of research-based management
recommendations, showed that on-station agronomic trials were required. The
agronomy research concentrates on improving soil fertility and water-holding
capacity through growing the Napier grass in an alley farming system utilising
Leucaena hedgerows, combined with intercropped herbaceous legumes and the
application of slurry (manure) (Mureithi, 1990).
The animal nutrition research is integrated closely with the forage
agronomy programme. Its objective is to develop feeding systems for zero-
grazed cows utilising the forage species from the agronomy programme. The
experiments have measured feed intakes, liveweight changes and lactation
performance of dairy cows fed a basal forage (Napier grass) diet supplemented
with protein using locally produced feeds, especially legume forages, and the
local crop byproducts copra cake and maize bran.
An experiment in 1989 with Jersey cows supplemented with 300 g crude
protein (CP) showed that dry-matter (DM) intakes and milk yields were similar
whether the protein supplement was supplied by copra cake or iresh Leucaena
forage. This result suggested that reasonable performance could be achieved by
supplementing a Napier basal diet with only a legume forage, which could be
produced cheaply and conveniently on-farm. Consequently during 1990 an
experiment was carried out to evaluate the effects on cow performance of level
oiLeucaena supplement and of the harvesting height of the Napier basal fodder.
MATERIALS AND METHODS
Study site
The experiment was carried out at the Regional Research Centre, Mtwapa,
Kenya, 20 km north-west of Mombasa in the coastal lowland coconut-cassava
agro-ecological zone (Jaetzold and Schimdt, 1983). During the study period,
March to November 1990, mean monthly minimum and maximum temperatures
were 20-24 and 24-27°C, respectively, and relative humidity was high. During
most of the experiment there was good rainfall and fast Napier grass growth.
77
Animals
Thirty-six Ayrshire/Brown Swiss x Sahiwal cows of known breed composition,
previous performance and service dates were purchased from a large local dairy
farm. They were representative of the crossbred dairy population found on
smallholder farms at the Kenya coast. They had had one to four previous
lactations. The cows were housed in a well ventilated zero-grazing unit where
they were fed chopped Napier fodder and some copra cake and maize bran until
calving. They were treated with the trypanocidal prophylactic drug
isometamidium chloride (Samorin), and drenched with levamisole
hydrochloride/oxyclozanide (Nilzan) against internal parasites. They were
sprayed weekly with a diamidide acaricide (Triatix) to control tick-borne
diseases.
Diets
Napier grass (Pennisetum purpureum cv Bana) was harvested daily at heights of
1.0 or 1.5 m, chopped with a motorised chopper into pieces about 20-50 mm
long and mixed thoroughly before feeding. Leucaena forage (about 280 g crude
protein/kg DM, 250 g DM/kg fresh matter) was harvested from well-established
hedgerows of the variety K28. It was cut in the evening for morning feeding and
in the morning for the afternoon feeding. Stems thicker than 5 mm in diameter
were removed from the forage before feeding.
Experiment procedure
The 36 cows were allocated to tw6 groups with greater or less than 50% Sahiwal
genes. Cows from each group were then assigned at calving to treatment groups
in a 2 x 3 factorial design to evaluate the effects of harvesting height of Napier
(1.0 or 1.5 m) and level of Leucaena supplement (0, 4 or 8 kg fresh weight).
Where possible the six treatment groups were balanced for postpartum body
weight. All cows had good body condition. The cows calved between 26 March
and 2 August and the experiment began on day 15 of lactation and lasted 98 days.
The cows were confined in individual stalls in the zero-grazing unit. Body
weights were recorded the day after calving, and weekly thereafter before
morning feeding. The cows were hand-milked at about 0500 and 1500 hours and
the milk production recorded. Water and mineral lick (19.95% Ca, 11.76% P,
10.26% Na, 0.16% Cu) were available at all times. Napier fodder was offered at
least twice daily to ensure constant availability of the fodder for ad libitum
feeding. From day 15 of lactation, the cows were fed according to treatment
group, the ad libitum Napier fodder, harvested at a height of 1.0 or 1.5 m,
supplemented with 0, 4 or 8 kg fresh weight of Leucaena forage. Feed refusals
were weighed and recorded before milking on the following day. There were no
78
Leucaena refusals. The Leucaena forage offered and the Napier fodder offered
and refused were sampled weekly on consecutive days; half of each sample was
dried at 85°C for laboratory analysis and the other half at 105°C for dry-matter
determination. Blood was sampled every fortnight to screen for trypanosomes,
and other health measures were taken as necessary.
Statistical analysis
Dry-matter (DM) intake of Napier, total DM intake, body weight change and
milk yield were analysed using the General Linear Model (GLM) for covariance
analysis of the SAS (1987) computer package. The linear model included the
independent variables, calving period (before or after the end of May), breed
group, Napier harvesting height, level ofLeucaena supplement and the
interaction of the latter two factors. Second-week body weight was a covariate in
the analyses of DM intake and liveweight change. Average daily milk yield in
the second week of lactation was a covariate for milk yield.
RESULTS
Only results for the production traits are presented here. Laboratory analyses
giving the digestibility, metabolisable energy and protein levels of the forage
samples are not yet available. These laboratory results will determine the final
interpretation of, and conclusions from, the results for the production traits.
All cows were in good health throughout the experiment, with the exception
of one cow which had to be replaced early in the experiment because of severe
mastitis, and another two cases of metritis which responded quickly to treatment.
Feed intake
Dry-matter intake of the basal Napier fodder was significantly (P<0.001)
affected by the harvesting height of the Napier grass (Table 1). The provision of
the Leucaena forage supplement did not significantly affect Napier dry-matter
intake. Not only was there no substitution effect, but there was an indication of
some stimulation of Napier intake when cows received the Leucaena
supplement. Consequently total DM intake was significantly affected (P<0.001)
both by harvesting height of Napier and by level ofLeucaena supplement.
Despite the large effects of Napier harvesting height and level ofLeucaena
supplement there was no significant harvesting height x supplement interaction.
However, there were indications in the latter period of the experiment that
interactions may have been important.
When expressed as a proportion of body weight, total DM intake for the six
dietary combinations ranged from 1.8 to 2.8%.
79
Table 1 . Mean daily Napier fodder and total (Napier plus Leucaena) dry-matter intakes of
lactating crossbred cows fed ad libitum Napier fodder harvested at 1.0 or 1.5 m
supplemented with 0,4 or 8 kg fresh Leucaena forage from day 15 to day 112 oflactation
Mean dry- matter intake (kg/day)
Total
Treatment D Napier (Napier plus Leucaena)
Napier harvest height (in)
1.0 18 9.3 10.5
1.5 17 6.8 7.9
SE 0.29 0.29
F-test of probability P<0.001 P<0.001
Leucaena supplement (kg)
0 12 7.8 7.8
4 11 8.2 9.3
8 12 8.2 10.4
SE 0.35
F-test of probability ns P<0.001
Body weight changes
Body weight losses occurred in all treatment groups, but the losses were more
marked in weeks 3 to 9 of lactation than later (Table 2).
There were no significant, nor apparently important, harvest height x
Leucaena supplement interactions for body weight change.
Milk production
Over the 14 weeks of the experiment both harvest height of Napier and level of
Leucaena supplement had significant effects (P<0.001 and P<0.05, respectively)
on mean daily milk yield (Table 3). Napier fodder harvested at 1.0 m rather than
1.5 m gave on average 1.7 kg (25%) per day more milk, with a greater advantage
(32% compared to 18%) in the second half of the experiment. Similarly there
was a differential response to level of Leucaena supplement during the two
halves of the experiment. The supplement did not affect mean daily milk yield
during weeks 3 to 9 of lactation when body weight losses (Table 2) were marked,
but it did have a significant (P<0.01) effect on milk yields in weeks 10 to 16
when body weight losses were lower. In the latter period, each 4 kg of fresh
Leucaena (about 1 kg DM) gave a response of about 0.8 kg more milk.
There were no significant Napier grass harvest height x level ofLeucaena
supplement interactions, but there were indications that in the latter half of the
experiment responses to Leucaena supplementation were higher in cows fed
Napier fodder harvested at 1.5 m.
80
Table 2. Mean body weight changesfor lactating crossbred cows fed ad libitum Napierfodder
harvested at 1.0 or 1.5 m supplemented with 0,4 or 8 kgfresh weight Leucaena forage
from day 15 to day 112 oflactation
Mean body weight change (kg)
Days 15-63 Days 64-112
Treatment Mean Mean
Overall
Mean
Napier harvest height (m)
1.0 18
L5 18
SE
F-test of probability
Leucaena supplement (leg)
0 12
4 12
8 12
SE
-8 18 -8 18 -16
-30 17 -18 17 -48
6.3 4.4 7.1
P<0.01 P<0.05 P<0.001
-37 12 -18 12 -55
-10 11 -10 11 -20
-10 12 -10 12 -20
7.9 5.5 9.0
P<0.01 na P<0.01F-test of probability
Table 3. Mean daily milk yieldfor lactating crossbred cows fed ad libitum Napierfodder
harvested at 1.0 or 1.5 m supplemented with 0,4 or 8 kgfresh weight Leucaena forage
from day 15 to day 112 oflactation
Mean milk yield (kg/day)
Days 15-63 Days 64-112 Overall
Treatment n Mean n Mean n Mean
Napier harvest height (m)
1.0 18 9.4 18 7.8 18 8.5
1.5 18 8.0 17 5.9 17 6.8
SE 0.30 0.35 0.30
F-test of probability P<0.001 P<0.001 P<0.001
Leucaena supplement (kg)
0 12 8.6 12 6.0 12 7.2
4 12 8.7 11 6.8 11 7.6
8 12 8.9 12 7.7 12 8.3
SE 0.36 0.42 0.36
F-test of probability ns P<0.01 P<0.05
81
DISCUSSION
This work set out to test the hypothesis that reasonable dairy cow performance
could be achieved by supplementing a basal diet of Napier fodder with only a
legume forage. Major improvements in performance were observed in cows fed
Napier fodder harvested at 1.0 m height, supplemented with 4 or 8 kg fresh
weight of Leucaena. Cows fed this diet had high DM intakes (approaching 3%
of body weight) which enabled them to maintain body weight and produce about
1000 kg milk in less than the first three months of lactation. With reasonable
subsequent nutrition a total lactation yield of at least 2000 kg could be expected.
The results highlight the important contribution legume forages can make to
achieving reasonable performance and to improving the utilisation of basal
forage diets. The higher level olLeucaena supplement gave on average 15%
more milk over the period of the experiment. The lack of response in the earlier
months may be explained by the greater mobilisation of body reserves by cows
not receiving Leucaena compared with those that were given the supplement.
Thus the main effect olLeucaena in early lactation was to reduce the loss of
body weight. In the third and fourth months of lactation the effect of the
supplement on milk production was large, with each 1 kg ofLeucaena DM
stimulating the production of about 0.8 kg of milk. Thus Leucaena
supplementation can make a very efficient contribution, both biologically and
economically, towards improving cow performance.
In the absence of laboratory analyses of the forages used in the experiment,
calculations based on expected values indicated that the diets were deficient in
energy. A small quantity of an energy-rich concentrate, maize bran, for example,
would therefore allow cows supplemented with Leucaena to utilise the available
protein more efficiently and produce more milk very cost-effectively. This
hypothesis was tested in a subsequent experiment which is now being analysed.
In the context of the smallholder, the legume is also expected to play an
important complementary role in improving the stability and sustainability of
Napier yields. As mentioned in the introduction, the agronomic studies, which
run concurrently with the nutrition research, evaluate the productivity and
sustainability of fodder production systems combining shrub and herbaceous
legumes grown in association with Napier grass. These studies will quantify the
output per unit area of sole stands of Napier grass and Leucaena and of their
mixed stands and intercrops with herbaceous legumes.
The importance of these agronomic studies is emphasised by the large effect
on cow performance of the harvesting height of the Napier fodder. By
quantifying the yields of Napier harvested at different heights throughout the
year, and then feeding those Napier fodders to cows in experiments similar to
that reported here, it will be possible to assess the relative productivities of the
systems in terms of output per area and per cow. When labour inputs are
included in the calculations, an economic evaluation can be applied and
recommendations developed.
82
REFERENCES
Jaetzold R and Schmidt H. 1983. Farm management ofKenya. Vol 11C, National
conditions andfarm management information. East Kenya (Eastern and Coast
Provinces). Farm Management Branch, Ministry of Agriculture, Nairobi, Kenya.
pp. 332-333.
Mureithi J G. 1990. Research onfeed resource development. Working Document 1 (June
1990). KARI/ILCA [Kenya Agricultural Research Institute/International Livestock
Centre for Africa] Collaborative Research on Smallholder Dairy Production in the
Coastal Subhumid Zone. ILCA, Mombasa, Kenya. 30 pp.
SAS (Statistical Analysis Systems Institute Inc). 1987. SAS/STAT. Guideforpersonal
computers, version 6 edition. SAS, Cary, North Carolina, USA pp. 551-640.
83
84
PERFORMANCE AND MANAGEMENT OF SHEEP ON RHODES
GRASS-STYLO PASTURE IN NIGERIA
O S Onifade1, IFAda2 andJ O Akinola3
National Animal Production Research Institute
Ahmadu Bello University
PMB 1096, Zaria, Nigeria
2
College of Animal Science and Livestock Production
University of Agriculture
Abeokuta, Nigeria
3 Department of Animal Production and Health
Ladoke Akintola University of Technology
Ogbomosho, Nigeria
ABSTRACT
An experiment was designed to study the effect of stocking rate on dry-matter
yield and animal performance on Rhodes grass-stylo (Chloris gayana cv
CaUid&Stylosanthes guianensis cv Cook) pasture over three grazing periods
(1986-1989) at Shika, Zaria, Nigeria. Sheep were continuously grazed at 12, 18,
24, 30 and 36 sheep/ha during the late wet to mid-dry season for 154 to 210 days
in each grazing period.
Stylo was eliminated after the first grazing period. Rhodes grass was still
dominant after three grazing periods. Yields of green and dead materials fell as
stocking rate increased. Daily liveweight gain decreased as stocking rate
increased and, gradually, as grazing progressed. Problems of managing sheep on
pasture, with respect to animal age and weight, time to commence grazing and to
give supplementary feed, and routine health practices, are discussed.
RESUME
Performances et gestion d'ovins eleves surpaturage d'herbe de Rhodes et de
Stylosanthes au Nigeria
Une expérience a &é effectuée a Shika dans la region de Zaria (Nigéria) en vue
d'etudier I'effet du taux de charge sur la production de matiere seche d'un
85
pâturage d'herbe de Rhodes fChloris gayana cv. Callide ) et de Stylosanthes
(Stylosanthes guianensis cv. Cook) ainsi que sur les performances d'ovins élevés
sur cepâturage. Conduit pendant trois périodes de pâturage (1986/89) longues
chacune de 154 à 210jours et allant de la fin de la saison humide au milieu de
la saison seche, cet essai a porte sur des taux de charge de 12, 18, 24, 30 et 36
animauxpar hectare.
La legumineuse a éte éliminée des la fin de la premiere période de pâturage
alors que l'herbe de Rhodes demeurait l'espece dominante à la fin de la
troisieme période. La production de materiel végétal, qu'il soit vert ou sec,
baissait avec l'accroissement du taux de charge. Les gains moyens quotidiens
diminuaient progressivement au fil du temps et au fur et à mesure qu'augmentait
le taux de charge. Les problèmes liés à la gestion des élevages ovins sur
pâturage ont éte examinés, notamment en ce qui concerne l'âge et le poids des
animaux, le choix au moment d'accès au pâturage ou aux aliments
complementaires ainsi que les interventions sanitaires de routine.
INTRODUCTION
The present system of sheep production in the Northern Guinea Savanna zone of
Nigeria is based on indoor feeding, grazing of natural or sown pastures or a
combination of these. The grazing of sown pastures is limited to universities,
research institutions and a few private farms where the performance of sheep can
be better evaluated.
There have been few grazing trials in Nigeria to determine productivity of
pasture, especially with sheep. In the humid zone, Sumberg (1985) grazed West
African Dwarf sheep on natural fallow regrowth in an integrated alley-farming
system sown to Leucaena leucocephala and Gliricidia sepium, and reported that
16 and 8 ewes could be supported per hectare during the wet (June-November)
and dry (November-March) seasons, respectively. He recorded a liveweight gain
of 218 kg/ha from ewes supplemented with concentrate during the dry season.
This study reports the effect of set stocking at the rates of 12, 18, 24, 30 and
36 rams/ha on the yield of a Rhodes grass-stylo pasture and on animal
liveweight gam.
MATERIALSAND METHODS
The experiment was carried out at the National Animal Production Research
Institute at Shika in the Northern Guinea Savanna zone of Nigeria. Climatic data
for the study area during the study period are presented in Table 1. The soils at
Shika are classified as ferruginous tropical soils (Klinkenberg and Higgins,
1968).
The animals used in the trial were Yankasa rams, the most common breed of
sheep in this ecological zone.
86
Table 1. Climatic datafor Shika and Samaru (10 km from Shika) during the grazing periods,
1986-1989
Rainfall (mm)
1986/87 1987/88 1988/89
During grazing period 420 253.5 88
Total annual 1071 1151 1066
Rainy days
During grazing period 19 20 9
Total annual 38 47 19
Samaru
Screen temperature (°C)
August 23.9 24.5 -
September 24.0 25.4 24.3
October 24.3 24.3 23.4
November 22.8 22.1 21.9
December 19.8 21.4 20.0
January 21.5 21.2 17.1
February 24.7 23.8 20.7
March 27.3 28.4 -
A mixed pasture of Rhodes grass (Chloris gayana cv Callide) and stylo
(Stylosanthes guianensis cv Cook) was sown at the study site in August 1985.
Seed was hand broadcast at the rate of 5 kg pure germinating seed (PGS)/ha: the
grass:legume seed ratio was 3:7. Phosphorus (30 kg/ha) was applied as single
superphosphate at establishment and again in July before each grazing period.
The pasture was set stocked on 21 August 1986 for 210 days, on 25 August 1987
for 196 days and on 12 September 1988 for 154 days. Herbage in each paddock
was cut back in May before each grazing period to remove uneven growth Five
stocking rates—12, 18, 24, 30 and 36 rams/ha—were arranged in a randomised
block design with two replicates. Stocking rates were achieved by adjusting
paddock size from 0.25 to 0.09 ha to accommodate three rams at the appropriate
rate.
The mean initial liveweight of Yankasa rams used in each grazing period
was 20 kg: the mean biomass of the three rams in all paddocks was similar. The
animals were treated with an anthelmintic and dipped before grazing began and
at four-week intervals thereafter. The animals were not provided with shade or
supplementary feed but were given water and mineral salt block in each
paddock. Rams were weighed every two weeks after a 14-hour overnight fast
(without feed or water) in an enclosure outside the paddocks.
87
Pasture components were sampled before each grazing period and then
every six weeks and at the end of the grazing period. Dry-matter yield on offer
was estimated by cutting from six random 0.5 x 0.5 m quadrats in each paddock.
The cutting was done at ground level with a hand sickle in the paddocks and
cages used as control. The herbage samples were weighed, mixed and two fresh
subsamples of about 500 g were taken. One was hand-sorted into green and dead
materials; the other remained intact. These were oven dried and weighed.
Data on forage and liveweight gains were subjected to analysis of variance.
Duncan's New Multiple Range Test (Steel and Torrie, 1980) was used to
compare means of stocking rate and grazing days.
RESULTS
Pasture dry-matter yields are shown in Table 2. Yields of both green and dead
material decreased as stocking rate increased. Yields of green material declined
significantly (P<0.05) as the grazing period progressed, while yields of dead
material increased. Stylo constituted only 11.2% of the total pasture yield at the
start of grazing in 1986. In the first grazing period (1986-87) the yields of stylo
at the various stocking rates were not different (P>0.05). The highest stylo yield
was recorded in the control plot. Stylo yields declined with increase in grazing
days at all stocking rates. Stylo was eliminated in the second grazing period,
except in the control plot where a mean yield of less than 0.5 t/ha was recorded.
In all grazing periods, daily liveweight gain of sheep decreased significantly
(P<0.05) as grazing progressed (Figure 1). Also, weight losses commenced
earlier in each successive grazing period. Daily liveweight gain also tended to
decrease with increasing stocking rate in all the grazing periods (Table 3). Using
the regression Yh = ax - bx for liveweight gain per hectare (Yh), where x is the
stocking rate and a and b are constants, the calculated optimum stocking rates in
the first, second and third grazing periods were 20.4, 24.9 and 21.2 sheep/ha. The
corresponding liveweight productions were 155.4, 186.2 and 129.4 kg/ha.
DISCUSSION
Stylo did not persist in the mixed pasture beyond the first grazing period. Winter
et al (1977), however, reported that stable pastures oiBrachiaria decumbens and
Panicum maximum with S. guianensis cv Endeavour were obtained after three
years of grazing with cattle at 0.7 and 2.2 animals/ha. Stocking rate in the first
grazing period did not suppress stylo yield in this trial as was observed in other
trials of grass-legume pastures grazed by sheep (Curll and Davidson, 1983; Curll
et al, 1985) and by cattle (Stobbs, 1970; Shaw, 1978; Eng et al, 1978).
The observed decline in stylo coverage caused by the companion Rhodes
grass agrees with a report from Thailand (Gutterridge, 1985) where ungrazed
stems of bamboo grass (Arundinaria ciliata) reduced the development of S.
88
Table 2. Effect ofstocking rates and grazing days on dry- matter yields ofgreen and dead
materials in the Rhodes grass—stylo pasture
Pasture component Dry-matter yield (t/ha)
Stocking rate (sheep/ha) 12 18 24 30 36 Control
19W87
Green 6.96b 6.96b 6.5 lbc 6.27cd 5.88d 8.67a
Dead 1.27a 1.04b 1.19ab 1.08b 1.05b 0.55c
Stylo 0.56 0.57 0.65 0.50 0.64 1.00
1987/88
Green 7.55a 7.21bc 7.27bc 6.86c 6.82c 8.81a
Dead 1.41a 1.29ab 1.20abc 1.16abc l.OObc 0.86c
1968/89
Green 7.30b 7.00bc 6.83c 6.60c 6.25d 8.88a
Dead 1.29a 1.25a 1.16b 1.01c 0.93c 0.82d
Grazing days 0 42 84 126 168 210
19JW87
Green 10.3a 9.5b 8.0c 5.4d 4.4e 3.7f
Dead 0.0 0.5d 0.8c 1.6b 1.6b 1.7a
1987/88
Green 9.5a 9.4a 7.5b 5.9c 4.8d -
Dead 0.6c 0.8b 1.1b 1.5b 1.7a -
1988/89
Green 8.8a 7.8b 6.7c 5.3d - -
Dead 0.4d 0.9c 1.3b 1.7a - -
Within a row, means followed by the same letter, or no letter, do not differ significantly (P>0.05)
humilis, S. hamata cv Verano and S. guianensis cv Endeavour. Earlier, Blair
Rains (1963) had observed that 24-hour stocking of stylo-based pastures in
Nigeria would reduce the legume content. The legume might have performed
better if its initial content in the pasture was higher.
Yields of green fodder declined as stocking rate and grazing days increased.
This finding supports work by Mears and Humphreys (1974) who reported
reductions in green matter of Kikuyu grass (Pennisetum clandestinum) as
stocking rate increased. Similarly, Watson and Whiteman (1981) reported a drop
in green yields of mixed pastures oiPanicum maximum and B. decumbens with
the legumes Centrosema pubescens, Macroptilium atropurpureum cv Siratro and
S. guianensis cv Endeavour as stocking rate increased from 1.8 to 4.5 animals/ha.
89
Figure 1. Daily liveweight changes ofsheep during three grazing periods
Liveweight changes
(g/head per day)
200
150
100-
-100
1986/87
1987/88
1988/89
 
100 150 250
1986/87 1987/88 1988/89
52 61 60
39 47 47
33 36 26
14 31 23
11 23 16
Grazing days
Table 3. Effect ofstocking rate on daily liveweight gain ofsheep during three grazing periods
Stocking rate (sheep/ha)
Daily liveweight gain (g/head)
12
18
24
30
36
90
The consumption of a high percentage of the green materials and
subsequent restriction of the formation of dead material (Greenwood and Arnold,
1968) and possible consumption of dead leafy materials at higher stocking rate
(Mears and Humphreys, 1974) could have resulted in the lowering of the yield of
dead material as stocking rate increased.
The decline in daily liveweight gain per animal as stocking rate increased
appeared to have arisen from differences in the amount of green material on offer
(Arnold, 1962) which followed the same pattern. As a result, sheep at the lowest
stocking rate had better opportunity to select herbage higher in crude protein and
lower in fibre (Weir and Torrell, 1959), hence the higher liveweight gain. In this
study it was observed that some rams were very slow to gain weight and some
came down with diarrhoea which could have affected the overall liveweight gain.
The general decline in liveweight gain as grazing progressed was attributed
to reduced nutritive value due to advanced plant maturity (Blunt, 1978), season
(Bryan and Evans, 1973; Okeagu, 1989) and thus reduction in herbage,
especially leaf, on offer (Laredo and Minson, 1973). From this study it can be
argued that sheep will start to lose weight at the highest and lowest stocking rates
in late December and late January, respectively, when the pasture is stocked in
August/September. Thus farmers should give supplementary feed or remove
animals or reduce stocking rates before these dates when grazing grass pasture.
Yearling rams and/or those above 20 kg were observed to survive better
than lighter animals. With respect to the time to stock the pasture, this study
would suggest periods before the flowering stage is reached or at sward heights
below the knee. A case of cutaneous myasis, an acute dermatitis of sheep caused
by blowfly (Chrysomia regalis) larvae was noticed in the second grazing period,
presumably because the pasture was high (over 100 cm) and dense. A less dense
canopy might discourage the fly. Predators and thefts can also account for losses
of animals on pasture. Adequate security and close fencing should be maintained
at all times. This will also enable a regular check to be made on the flock to
monitor the health of the animals and allow immediate treatment.
ACKNOWLEDGEMENTS
The authors would like to express their appreciation to Messrs Ayuba Mahuta,
Ashiru Mohammed and Bala Musa for field assistance and S A S Olorunju
(NAPRI biometrician) for statistical analysis. We thank the Director of NAPRI
for provision of facilities and permission to publish this paper.
REFERENCES
Arnold G W. 1962. Effects of pasture maturity on the diet of sheep. Australian Journal of
Agricultural Research 13:701-706.
91
Blair Rains A. 1963. Grassland research in northern Nigeria, 1952-1962. Samaru
Miscellaneous Paper No 1. Institute of Agricultural Research, Ahmadu Bello
University, Zaria, Nigeria. 69 pp.
Blunt C G. 1978. The production from steers grazing nitrogen fertilized irrigated pangola
grass in the Ord Valley. Tropical Grasslands 12:90-96.
Bryan W W and Evans T R. 1973. Effect of soils, fertilizers and stocking rates on pastures
and beef production on the Wall urn of south-eastern Queensland. 1. Botanical
composition and chemical effects of plants and soils. Australian Journal of
ExperimentalAgriculture andAnimal Husbandry 13:516-529.
Curll M L and Davidson J L. 1983. Defoliation and productivity of a Phalaris-
subterranean clover sward, and the influence of grazing experience on sheep intake.
Grass and Forage Science 38: 159-167.
Curll M L, Wilkins R J, Snaydon R W and Shanmu-Galingam V S. 1985. The effect of
stocking rate and nitrogen fertilizer on a perennial rye grass-white clover sward. 1.
Sward and sheep performance. Grass and Forage Science 40: 129—140.
Eng P K, Kerridge P C and Mannetje L ' t. 1978. Effects of phosphorus and stocking rate
on pasture and animal production from a guinea grass-legume pasture in Johore,
Malaysia. 1. Dry matter yields, botanical composition and chemical composition.
Tropical Grasslands 12:188-197.
Greenwood E A N and Arnold G W. 1968. The quality and frequency of removal of
herbage from an emerging annual grass sward by sheep in a set-stocked system of
grazing. Journal ofthe British Grassland Society 23: 144-148.
Gutterridge R C. 1985. The productivity of native grasslands oversown with legumes and
grazed at five stocking rates in north east Thailand. Journal ofAgricultural Science,
Cambridge 104:191-198.
Klinkenberg K and Higgins G M. 1968. An outline of Northern Nigeria soils. Nigerian
Journal ofScience 2:91-115.
Laredo M A and Minson D J. 1973. The voluntary intake, digestibility and retention time
by sheep of leaf and stem fractions of five grasses. Australian Journal ofAgricultural
Research 24:875-888.
Mears P T and Humphreys L R. 1974. Nitrogen response and stocking rate oiPennisetum
clandestinum pastures. 1. Pasture nitrogen requirement and concentration, distribution
of dry matter and botanical composition. Journal ofAgricultural Science, Cambridge
83:451-467.
Okeagu M U. 1989. The productivity o/Brachiaria and Digilaria pastures in the Northern
Guinea Savanna Zone ofNigeria. PhD Thesis. Ahmadu Bello University, Zaria,
Nigeria. 220 pp.
Shaw N H. 1978. Superphosphate and stocking rate effect on a native pasture oversown
with Stylosanthes humilis in central coastal Queensland. 2. Animal production.
Australian Journal ofExperimentalAgriculture andAnimalHusbandry 18:800-807.
Steel R G D and Torrie J H. 1980. Principles andprocedures ofstatistics. A biomedical
approach. 2nd edition. McGraw-Hill, New York, USA. 633 pp.
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Stobbs T H. 1970. The use of liveweight gain trials for pasture evaluation in the tropics. 6.
A fixed stocking rate design. Journal of the British Grassland Society 25:73-77.
Sumberg J E. 1985. Small ruminant feed production in a farming systems context. In:
Sumberg J E and Cassaday K. (eds), Sheep and goat production in humid West Africa.
Proceedings of a workshop on small ruminant production systems in the humid zone
of West Africa, held in Ibadan. Nigeria 23-26 January 1984. ILCA (International
Livestock Centre for Africa), Addis Ababa, Ethiopia. pp. 41-46.
Watson S E and Whiteman P C. 1981. Grazing studies on the Guadalcanal Plains,
Solomon Islands. 2. Effects of pasture mixtures and stocking rates on animal
production and pasture components. Journal ofAgricultural Science, Cambridge
97:353-364.
Weir W C and Torrell D T. 1959. Selective grazing by sheep as shown by a comparison of
the chemical composition of range and pasture forage obtained by hand clipping and
that collected by esophageal fistulated sheep. Journal ofAnimal Science 18:641-648.
Winter W H, Edye L A, Megarrity R G and William W T. 1977. Effects of fertilizer and
stocking rate on pasture and beef production from sown pastures in Northern Cape
York Peninsula. 1. Botanical and chemical composition of the pasture. Australian
Journal ofExperimentalAgriculture andAnimal Husbandry 17:66-74
93
94
EFFECTS OF ENVIRONMENT, BOTANICAL COMPOSITION
AND NUTRITION ON GOAT PRODUCTION ON ACACIA
SAVANNA IN KENYA
PNKamau andE KMaranga
Department of Natural Resources
Faculty of Agriculture
Egerton University
PO Box 536, Njoro, Kenya
ABSTRACT
Effects of botanical composition and environmental variables on dietary
preference and nutrition of goats were evaluated at Kiboko, Kenya, over one dry
season (June-September) and one wet season (October-November). Mature
oesophageally fistulated East African goats were used in the study. Dietary
behaviour of goats reflected a high degree of seasonal plasticity with regard to
forage types and plant species and plant parts eaten. Graminoid forage, forb and
browse herbage availability was correlated with soil moisture. Crude-protein
levels in ingested diets were generally high and tended to peak in November due
to increased moisture recharge at this time. In vitro organic matter digestibility
(IVOMD) was closely related to soil moisture. High IVOMD values were
observed at the beginning of the dry and wet seasons. Ingested digestible energy
increased as forbs, grasses and immature browses increased in the diets in
response to increased soil moisture availability.
RESUME
Effet de I 'environnement, de la composition botanique des pdturages et de
I'alimentation sur le comportement alimentaire des caprins dans la savane
d 'Acacia au Kenya
L'effet de la composition botanique des pâturages et desfacteurs ecologiques
sur les preferences et le comportement alimentaires des caprins a ete etudie a
Kiboko (Kenya) au cours d'une saison seche (juin-septembre) et d'une saison
humide (octobre-novembre). Cette experience a porté sur des caprins d'Afrique
de I'Est munis defistules oesophagiennes. II ressort des resultats enregistres que
ces animaux avaient un comportement alimentaire tres saisonnier, notamment en
95
ce qui coneerne le type de fourrage, les especes vegétales et les parties des
plantes qu'ils consommaient. II existait une corrélation positive entre d'une part,
les disponibilites enfourrage gramineen, en herbe et en ligneux et de I' autre,
I'humidite du soL La teneur en proteines brutes des fractions ingerees etait
genéralement élevee et tendait vers un maximum en novembre, en raison de
I'accroissement du degre hygrometrique du sol a cette epoque de I'annee. II
existait en outre une étroite relation entre la digestibilite in vitro de la matiere
organique et I'humidite du sol. Consequence enfxn de I'accroissement de
I'humidite du sol, la consommation d'herbe, de graminees etdefourrage ligneux
tendre augmentait, entrainant un accroissement de la consommation d'énergie
digestible des animaux.
96
ETUDE DE L'INFLUENCE DE QUATRE FOURRAGES
LIGNEUX SUR L'EVOLUTION PONDERALE DES OVINS DE
LA RACE NAINE DE L'AFRIQUE DE L'OUEST
/. Kouonmenioc , A. Lacoste et H. Guerin
Station de recherches zootechniques de Nkolbisson
B.P. 1457, Yaoundé (Cameroun)
Laboratoire de biologie vegétale B
Université de Paris XI
Centre d' ORSAY (France)
Tnstitut d' é1evage et de medecine vétennaire des pays tropicaux (IEMVT)
10, rue Pierre Curie, Maisons-Alfort (France)
RESUME
Des essais d' alimentation destines a comparer divers regimes ont ete effectues
pendant 74 jours sur des ovins de la race naine de 1' Afrique de 1' Ouest élevés en
stabulation et en cases individuelles. Leur ration etait composee de graminees
(Pennisetum purpureum) pures ou complémentées avec du fourrage ligneux
(Alchornea cordifolia, Flemingia macrophylla, Gliricidla sepium ou Leucaena
leucocephala). Ni le poids initial, ni le mode d' élevage n' avaient d'effet
significatif sur les gains moyens quotidiens (GMQ), mais le type de fourrage
ligneux avait une influence significative (F= 1 8,1 3; P<0,05) sur ce parametre. Le
lot soumis a la ration exclusivement gramineenne a enregistre des pertes de poids
et une mortalite dlevee (60%), ce qui montre que ce regime etait inadequat pour
maintenir en bon état pendant une longue periode de temps des animaux eleves
en stabulation. La complementation avec Gliricidia sepium donnait les meilleurs
resultats, avec un GMQ de 64,14 g. Les performances associees a Leucaena
leucocephala ne refletaient pas la valeur energétique et azotee de ce fourrage, ses
potentialités reelles ayant probablement ete masquees par les effets de la
mimosine, alcaloide toxique present dans toutes les parties de la plante. Enfin,
bien qu' il s' agisse d' une légumineuse, Flemingia macrophylla ne semble pas
particulièrement indique' pour promouvoir la croissance pondérale chez les ovins.
97
ABSTRACT
Study ofthe effect offourfodder browses on weight changes in WestAfrican
Dwarfsheep
Feeding trials were carried out on individually pennedAfrican DwarfForest
sheep over a 74-dayperiod Diets consisted o/Pennisetum purpureum (grass)
either alone or combined with a browse plant (Alchornea cordifolia, Flemingia
macrophylla, Gliricidia sepium or Leucaena leucocepbalaj. Weight gain was not
affected by the initial weight or the type ofhousing, but was significantly
(F=18.13; P<0.05) affected by the browse species. The group receiving
Pennisetum purpureum alone lost weight and suffered a high mortality (60%).
This shows that Permiseturn is not suitablefor keeping confined animals in good
health for long periods oftime. Supplementation with Gliricidia sepium proved
to be the best combination, with an average daily weight gain of64.14 g. The
performance ofthe group receiving Leucaena leucocephala did not reflect the
energy andprotein value ofthis forage, as its potentials may have been obscured
by the presence ofmimosine, a toxic alkaloidfound in allparts ofthe plant.
Although Flemingia macrophylla is a legume, the results showed that this species
is not suitableforpromoting growth in this sheep breed.
INTRODUCTION
Dans de nombreuses régions du monde, et plus particulièrement en Afrique
tropicale, le manque de ressources fourragères de bonne qualité constitue un
obstacle de taille au développement de la production animale. La pénurie est
encore plus marquée dans les régions à très faible pluviométrie où la seule
végétation permanente est constituée d' espèces ligneuses. De nombreux auteurs
(Dayton, 1931 cité par Skerman, 1982; Curasson, 1956; Boudet, 1979;
Harrington et Wilson, 1980; Skerman, 1982; Guérin et al., 1987; Koné, 1987)
sont unanimes pour reconnaître l' importance des ligneux dans l' alimentation du
bétail, principalement comme source d' azote pouvant servir de complément aux
fourrages herbacés dont la qualité nutritionnelle se dégrade rapidement au cours
du cycle de développement.
En ce qui concerne plus précisément le Cameroun, les données relatives aux
fourrages ligneux et à leur utilisation par les ruminants restent limitées. Les seuls
documents pertinents connus découlent des travaux de Piot (1966, 1969, 1970),
réalisés sur le plateau de l' Adamaoua en zone soudano-guinéenne. Cet auteur
fournit sur cette région une liste plus ou moins exhaustive des ligneux appétés
par les bovins, ainsi que la composition chimique des principales espèces. La
présente étude est destinée à identifier des essences ligneuses qui, en association
avec les principales graminées spontanées ou cultivées, pourraient contribuer à
promouvoir le développement de la production des petits ruminants et permettre
ainsi de mieux répondre aux besoins des populations en protéines animales.
98
MATERIELS ET METHODES
Cette experience a etc realisee sur 25 ovins de la race naine de 1' Afrique de
1' Ouest, de poids moyen égal a 15 kg. La protection sanitaire des animaux a 6té
assuree par un déparasitage externe et interne, respectivement a base d' une
solution de Tigal et de Panacur .
Les essais se sont deroules dans un batiment de type "semi plein air" a la
Station de recherches zootechniques de Nkolbisson.
Le dispositif experimental correspond a celui du bloc aleatoire a
randomisation totale a cinq repétitions.
On trouvera au tableau 1 la composition des cinq regimes alimentaires
utilises. Cinq lots de poids homogene, constirues chacun de cinq animaux, ont
éte constirues et affectes chacun a un regime alimentaire donné. Ce processus
d' affectation, de même que 1' attribution des cases individuelles au sein de
chaque bloc, a ete effectue au hasard.
Les divers fourrages ligneux ont i\i décrits par Kouonmenioc (1990).
Toutes les especes ligneuses testees ici ont ete cultivees, exception faite de
Alchornea cordifolia qui, tout comme Pennisetum purpureum, a été ricoltd a
l'état naturel.
L experimentation s' est deroulee en deux phases distinctes, a savoir une
periode preexperimentale de 15 jours et une periode expérimentale de 59 jours.
Les fourrages ont ete recoltes et distribues tous les jours entre 7 heures et
8 h 30. Le taux de matiere seche de chaque type de fourrage a ete determine. A
1' issue de 1' essai, un mélange constirue des echantillons moyens hebdomadaires
a éte analyst en vue de determiner la composition chimique globale du fourrage
consider6.
La quantité de matiere seche effectivement ingeree chaque jour a ete
mesuree individuellement par pesee des quantités de fourrages offertes et des
refus.
En ce qui concerne les rations binaires, la distribution des deux
composantes a eté effectuee en fonction des differences d' appétibilité observees.
Ainsi, pour certaines rations (Pennisetum + Leucaena et Pennisetum +
Flemingia), il a fallu procéder a une distribution "décalée", stratégie visant a
induire une consommation "forcee" de 1' espece peu appetee.
Tableau 1. Regimes alimentaires
Composante heibacee Composante ligneuse
Pennisetum purpureum Alchornea cordifolia
Pennisetum purpureum Flemingia macrophylla
Pennisetum purpureum Gliricidia septum
Pennisetum purpureum Leucaena leucocephala
Pennisetum purpureum seul -
99
Les animaux dont la ration était constituée exclusivement de Pennisetum
purpureum recevaient cette graminée ad libitum. Par contre, Pennisetum était
rationné dans les rations mixtes où les fourrages ligneux étaient en revanche
offerts ad libitum.
Les fourrages ligneux ont été distribués sous forme de rameaux feuilles
alors que Pennisetum était présenté à l' état entier.
La distribution des ligneux sous forme de rameaux conduit à distinguer
deux types de refus, à savoir le refus "brut", équivalant à la quantité totale non
consommée (feuilles + tiges) et le refus "réel", constitué par la partie
consommable mais non consommée du refus brut.
Les animaux disposaient en permanence d' un complément minéral (55% de
poudre d' os, 40% de NaCl, 5% d' oligo-éléments). L eau était fournie ad libitum.
Une simple pesée a été effectuée hebdomadairement et le poids initial a été
déterminé par une triple pesée marquant la fin de la phase d' accoutumance.
Les gains moyens quotidiens (GMQ) ont été soumis à une analyse de
variance et l' influence d' un effet secondaire "loge" (bloc) sur les GMQ a été
testée. La relation entre le poids initial individuel et le GMQ a été déterminée
pour I' ensemble des cinq régimes.
RESULTATS
Bien que l' étude ait porté sur cinq traitements, la différence statistique entre les
GMQ n' a été recherchée que pour les rations mixtes. Le lot témoin dont le
régime était constitué exclusivement de Permisetum a été exclu de l' analyse en
raison des fortes mortalités (60%) qui y avaient été enregistrées. Ces mortalités
étaient presque partout précédées des mêmes symptômes, à savoir baisse de
consommation, pertes importantes de poids, diarrhées légères et parfois
persistantes conduisant à la mort de l' animal. Les résultats des autopsies n' ont
révélé aucune anomalie dans les organes internes.
L analyse comparative des gains de poids des animaux soumis aux régimes
à base de Alchornea cordifolia, Gliricidia sepium, Leucaena leucocephala et
Flemingia macrophylla n' a révélé aucune relation significative entre le poids
initial et les GMQ individuels (r=0,26) (figure 1). Par ailleurs, alors que le
paramètre "loge" (bloc) n'avait aucune influence significative (F=0,55; tableau
2) sur les GMQ, ceux-ci variaient significativement (F=18,12 au seuil de 5%) en
fonction du type de fourrage ligneux. Enfin, la comparaison des moyennes des
GMQ par le biais du test de Newman-Keuls permet de regrouper les traitements
en 3 catégories, à savoir A (Gliricidia sepium), B (Alchornea cordifolia) et C
(Flemingia macrophylla et Leucaena leucocephala) (voir tableau 3 et figure 2).
Les chiffres moyens hebdomadaires d' ingestion quotidienne des fourrages
(g/kg P ' ) ont permis de dresser les bilans de consommation.
100
Figure 1. Relation cntrepoids initial etgain moyen quotidien (GMQ) individuels
GMQ individuel
(9)
100n
80-
60- •
40
20-
-20
-40
10 12 14 16 18 20
Poids initial (kg)
DISCUSSIONS
Regime sans complementation
Avec la ration constitute uniquement de Pennisetum purpureum, les GMQ
n' etaient posiufs que durant les deux semaines suivant la phase d' accoutumance.
On peut penser que la qualité nutritive mediocre de la graminee (tableau 4) a été
compensee par de fortes consommations (113 g de MS/kg P ' /j).
Tableau 2. Analyse de variance de Veffet de Vespece ligneuse sur les GMQ des ovins
Carres Niveau de
SCE ddl. moyens TestF probability
Variance totale 23 301,79 18 1 294,54
Variance facteur 1 1874,05 3 6 251,35 18,13 0,0002
Variance blocs 755,35 4 188,84 0,55 0,7065
Variance residuelle 1 3 792,39 11 344,76
SCE : somme des carres des ecarts
d.dl. : degre de liberty
101
Tableau 3. Comparison des moyennes de GMQ des traitements (Test de Newman—Keuls au seuil
de5%)
Nombre de moyennes 2 3 4
PPAS 25,87 31,69 35,32
Traitements Moyennes Groupes homogenes
Gliricidia septum 64,07 A
Alchomea cordifolia 24,6 H
Flemingia macrophylla - 9,14 C
Leucaena leucocephala -11,19 c
PPAS: plus petite amplitude significative
Les pertes de poids s' amorcaient alors, puis augmentaient pour aboutir a des
mortalites. Ces mauvaises performances semblaient liees a la chute importante
des quantites ingerees, lesquelles passaient de 113 a 55 g de MS/kg P ' du
debut a la fin de l' experience.
Les resultats de l' analyse de la composition chimique effectuee sur
Pennisetum purpureum (tableau 4) confinnent les conclusions de Gudrin (1987)
sur la valeur alimentaire des graminees tropicales. Celui-ci note que par
comparaison avec les graminees temperees, les graminees tropicales sont plus
riches en constituants pariétaux et pauvres en matieres azotees totalcs avec de
surcroit de faibles taux de digestibilité de la matiere organique et de la matiere
seche. Ainsi, la dégradabiliie enzymatique de la matiere organique de
Pennisetum est de 34,3% (tableau 4) contre 47% pour une graminee tempéree
comme Festuca pratensis.
Soulignons cntin que la faible solubilit6 des matieres azotees, soit 20,6%
(tableau 4), est peut-etre lice a la presence de tanins. Ceux- ci, surtout abondants
chez les ligneux, se rencontrent parfois egalement en fortes quantites chez
certaines especes herbacees perennes (McLeod, 1975).
Bien que Boudet (1975) souligne que Pennisetum purpureum est une
graminée pauvre en energie quel que soit son stade de croissance, un fourrage
plus jeune aurait probablement donne lieu a de meilleures performances.
Cependant, des cas severes de diarrhees ont souvent et6 signalés chez les
animaux consommant des plantes herbacees tres jeunes.
Les carences alimentaires associces a ce regime alimentaire purement
graminee n sont en harmonie avec les resultats d' essais preli minaires du meme
type realises auparavant sur des ovins et des caprins (Kouonmenioc, 1986). Tous
les six animaux de chacun des deux lots recevant uniquement des graminees
etaient mods, par opposition a ceux soumis aux rations mixtes. Cependant,
compte tenu de l' origine des animaux utilises dans ces essais ("tout venant"), et
du dispositif experimental (alimentation en groupe), on ne pouvait tirer aucune
conclusion definitive de cette constatation.
102
Figure 2. Evolution du poids moyen des ovins en fonction de la nature du fourrage ligneux contenu
dans le régime alimentaire
Poids
(kg)
20 n
19
18-
17
16-
15-
14-
13
Leucaena leucocephala
-• Flemingia macrophylla
-A Gliricidia sepium
-* Alchornea cordifolia
 
1
29.07.8815.07.88 12.08.88 26.08.88 09.09.88 13.09.88
Date des pesées
Ces résultats posent le problème du maintien des ruminants domestiques sur
les "prairies" graminéennes, source de l' essentiel de l' alimentation des animaux
d' élevage dans les régions tropicales. Sous une relative homogénéité
physionomique liée à la prédominance d' une ou de quelques espèces
graminéennes, la plupart de ces formations sont en effet caractérisées par une
grande diversité de composition, fréquemment liée à l' existence d' une strate
herbacée inférieure bien développée. C est le cas des pâturages des hauts
103
Tableau 4. Teneurs en constituents organiques des especes fourrageres utilisees
Constituants
Alchornea Flemingia Leucaena Gliricidia Pennisetum
cordifolia macrophylla leucocephala sepium purpureum
Constituants parietaux (% de MS)
Cellulose brute (CB)
1'arois totales (NDF)
Lignocellulose (ADF)
l.ignine (ADL)
Matieres azotees
Mat azotees totales
(%MS)
Mat. azot. solubles
(%MAT)
Mat azot. residuelles
deI'ADF(%MAT)
Degradabilile enzymatique
de la matiere organique
des matieres azotees
19,01 30,86
34,04 59,39
25,58 53,04
7,17 29,31
16,92 18,39
7,63 18,86
9,77 37,66
57,29 26,54
52,94 46,15
19,00 18,03 35,50
27,72 33,33 68,70
18,76 23,61 36,10
8,14 8,90 3,80
24,66 22,80 11,20
21,47 36,21 20,6
7,23 8,09
53,18 60,66 34,30
71,55 74,51 20,60
plateaux de l' ouest du Camcroun ou existent en abondance, entre les tpufi'es de
l'espece dominante Sporobolus africanus, de nombreuses petites légumineuses
tres appétees comme Trifolium repens, T. baccarinii, T. usambarense et capables
d' assurer le complément necessaire a l' equilibre alimentaire des animaux.
Complementation avec Gliricidia sepium
Les animaux beneficiant d' une complémentation avec Gliricidia sepium avaient
la croissance la plus rapide avec un GMQ de 64 g, chiSre equivalant a ceux
obtenus avec des aliments complémentaires composes de concentres.
Indépendamment des qualités nutritionnelles de Gliricidia, les GMQ eleves
enregistres ici etaient associes a une consommation elevee de fourrages
s' etablissant en moyenne a 141 g de MS/kg P°'75/j, dont 65% de Gliricidia.
Celle-ci est superieure, non seulement a la moyenne de 2,5 kg de MS/100 kg de
poids vif, soit 79 g de MS/kg P0,75/j (Boudet et Riviere, 1968) consideree
comme normale, mais 6galement aux chiffires rapportes par de nombreux auteurs
dont Reyne et Garambois (1975), Van Eys et al. (1986), Kone (1987), Guerin
(1987) et Richard (1987). Ces valeurs, de mfime d' ailleurs que les resultats de la
présente étude, demeurent cependant inferieures a la consommation record de
162 g de MS/kg P°'75/j obtenue en Libye par Le Hou6rou (1987) dans un essai
d' alimentation en enclos effectué sur des ovins dont le régime alimentaire 6tait
104
composé uniquement de trois fourrages ligneux (Atriplex nummularia, A. halinus
et Acacia saligna).
Notons que les chiffres de consommation les plus fréquents rapportés sur
les ovins en zone tropicale se situent entre 45 et 82 g de MS/kg P0' /j pour des
animaux pâturant librement des parcours naturels. Ces résultats dépendent bien
évidemment d' un certain nombre de paramètres liés tant à la végétation qu' au
comportement de l' animal, notamment la fréquence des éventuels déplacements.
Pour sa part, Nebout (1978) souligne que la consommation de fourrage dépend
non seulement du poids du sujet et de l' espèce animale, mais également de la
quantité et de la qualité du fourrage disponible.
Ademosum et al. (1985) rapportent que la présence de Gliricidia dans une
ration en augmente la consommation de matière sèche et probablement la
digestibilité. Us ont noté, au cours d' un essai effectué sur des caprins recevant
Panicum maximum ad libitum comme aliment de base et Gliricidia sepium
(quatre niveaux) comme aliment complémentaire, que les animaux recevant le
niveau le plus élevé de complémentation ne refusaient jamais Gliricidia et
avaient une consommation de 37,7% supérieure à celle du groupe témoin soumis
au régime exclusivement graminéen.
Par ailleurs, l' utilisation de fourrage de Gliricidia issu indifféremment de 14
cultivars n' a donné lieu à aucune différence significative dans les quantités
ingérées. Cette constatation semble en contradiction avec les observations de
Glander (1979, 1981 d' après Nancy, 1987) qui mentionne une influence de la
variabilité génétique de l' espèce végétale sur l' appétibilité.
Enfin l' alimentation à base de Gliricidia n' a eu aucune incidence
pathologique ou dépressive sur les animaux.
Complémentation avec Alchornea cordifolia
Avec un GMQ de 25 g, la complémentation avec Alchornea cordifolia se classait
en deuxième position. La consommation moyenne était de 120 g de MS/
kg P ' /j et augmentait au cours de la phase d' expérimentation (rapport de 1,6).
Alchornea entrait ici pour 48% dans cette consommation contre 64,6% pour
Gliricidia. Une aussi faible différence d' ingestion (15%) entre ces deux espèces
ne peut expliquer des écarts de GMQ aussi importants (62%) entre les deux
régimes. Ces différences semblent donc directement liées à la nature et à la
composition chimique des deux espèces (tableau 4).
Le taux de dégradabilité de la matière azotée totale (tableau 4) à! Alchornea
cordifolia (52,9%) est nettement inférieur à celui de Gliricidia (78,8%). Enfin, la
probable hétérogénéité du fourrage à!Alchornea, du fait qu' il a été récolté à
l' état naturel, est peut-être pour quelque chose dans les faibles GMQ associés à
cette espèce ligneuse.
Un fourrage d' Alchornea à base de rameaux plus jeunes aurait peut-être
permis de meilleures performances. Cela nécessiterait cependant un rabattage en
vue de l' utilisation des repousses.
105
Complémentation avec Flemingia macrophylla
Le GMQ relatif à toute la période de l'expérience était négatif (-9,1 g). Les
GMQ individuels étaient caractérisés par une grande variabilité au sein du lot
(constance, gains et pertes de poids). Les baisses de poids étaient probablement
dues aux qualités nutritionnelles médiocres de cette espèce dont la teneur en
matières azotées totales (MAT) était seulement de 18% (tableau 4), valeur
voisine de celle d'Alchornea cordifolia. Par ailleurs, les tests de dégradabilité
enzymatique (pepsine-cellulase) ont révélé que moins de la moitié (42,2%) de
ces MAT étaient digestibles. La consommation était en moyenne de 140,1 g de
MS/kg P ' /j, valeur très proche de celle relative à la meilleure
complémentation, c' est-à-dire avec Gliricidia sepium.
Sur la base de ces résultats, on peut conclure que bien qu' il s' agisse d' une
légumineuse, Flemingia macrophylla est peu indiqué pour la production
animale. De fait, Asare (1985), à 1 issue d' essais pourtant très satisfaisants
effectués sur diverses caractéristiques agronomiques de cette espèce ligneuse
(production de biomasse foliaire), a insisté sur la nécessité, avant toute tentative
de vulgarisation, de mener des études sur l' appétibilité et l' ingestion de
Flemingia afin de tester l' influence desdites caractéristiques sur les paramètres
zootechniques objectifs (production de viande, de lait).
A défaut de l' utiliser en production animale, on pourrait cependant exploiter
sa forte capacité de production pour produire de la litière qui servirait à limiter le
développement des adventices dans certaines cultures pérermes (plantations de
café, par exemple). Etant donné qu' il s' agit d' une légumineuse, Flemingia
pourrait en outre servir à enrichir les sols en vue de la production végétale.
Complémentation avec Leucaena leucocephala
Le GMQ relatif à toute la durée de l' expérience était négatif (-11,2 g).
La moyenne de consommation était de 107,9 g de MS/kg P0' /j. La
consommation avait considérablement diminué au cours de l' expérience, passant
de 144 à 72 g de MS/kg P ' /j au cours de la dernière semaine, soit une baisse
de 50%.
Les résultats enregistrés ici sont plutôt surprenants, compte tenu du fait que
les feuilles de Leucaena avaient la teneur en MAT la plus élevée des quatre
ligneux étudiés. De plus, leur digestibilité à la pepsine, égale à 71,6% (tableau 4)
était proche de celle de Gliricidia, espèce associée aux meilleures performances
pondérales enregistrées dans le cadre de cet essai.
Ces chiffres peuvent s' expliquer par des perturbations notées chez les
animaux, correspondant probablement à des symptômes d' intoxication par la
mimosine, une toxine présente dans toutes les parties de la plante. La toxicité de
cette substance, par accumulation dans l' organisme, a déjà été soulignée par
plusieurs auteurs chez les monogastriques (Hegarty et ai, 1964; Hamilton et al.,
1968; Shiroma et Takahashi, 1976).
106
Chez les polygastriques cependant, il n' y a danger que lorsque Leucaena
entre pour plus de 50% dans la ration. Divers signes cliniques étaient néanmoins
apparus au cours de cette étude, y compris des émissions intenses de bave,
l' incoordination des mouvements, la perte de la voix, l' alternance de pertes et de
reprises d' appétit et des pertes sensibles de poids. Toutefois, bien qu' on n' ait
observé aucun des phénomènes couramment cités comme signes d' une
intoxication à la mimosine— alopécie (Hegarty et al., 1964; Reis et al, 1975) et
hypertrophie thyroïdienne — il y a cependant tout lieu de soupçonner ce type
d' empoisonnement.
Cette intoxication semble liée au fait que les ovins, très friands des feuilles
de Leucaena, avaient presque complètement délaissé le Pennisetum et ce, malgré
le décalage entre la distribution des fourrages de ces deux espèces. En effet, les
animaux s'étaient semble-t-il très vite adaptés au rythme adopté, préférant jeûner
toute la matinée dans l' attente de la distribution du fourrage de Leucaena.
Si l' on considère que, pour tous les autres régimes, la consommation
d' éléments ligneux avait augmenté avec la durée de l' expérience, on peut penser
que sans les phénomènes d' intoxication constatés, les performances de cette
ration seraient proches de celles du meilleur régime alimentaire, c' est-à-dire
celui complémenté avec du fourrage de Gliricidia.
Ces résultats ne doivent cependant pas conduire à remettre globalement en
cause la valeur du Leucaena leucocephala en production animale, en particulier
dans la production bovine sur laquelle ont porté la majorité des travaux à ce jour.
Ainsi, au Malawi, de jeunes animaux métis Zébu x race frisonne, alimentés avec
des rations composées de Leucaena, de son et de tiges de mais, ont présenté des
gains de poids de 1,17 kg/tête/j (Thomas et Addy, 1977). Pour sa part, Jones
(1979) rapporte qu' en Indonésie et dans l'île de Timor, des bovins engraissés
pendant 6 mois, uniquement avec un mélange de Leucaena et de stipes de
bananiers, avaient enregistré des GMQ satisfaisants pendant les trois premiers
mois, après quoi on assistait à un ralentissement de la croissance pondérale avec
apparition de symptômes graves d' intoxication. Il en conclut que la toxicité est
cumulative quand les animaux consomment du Leucaena pendant une longue
période de temps.
Un certain nombre de recherches sont actuellement en cours sur ce sujet,
notamment en Australie. Celles-ci visent entre autres soit à créer dans le tube
digestif des ruminants les conditions favorables au développement de bactéries
capables de dégrader la mimosine (Reed et Chater, 1986), soit à produire des
souches de Leucaena pauvres en mimosine.
CONCLUSION
Un essai d' alimentation qui, comme celui présenté ici, est caractérisé par le suivi
individuel des animaux semble constituer, par rapport aux estimations
d' ingestion sur parcours, une méthode plus objective de mesure des chiffres de
consommation. Même si cette approche complique sérieusement les expériences,
107
ellc devrait cependant permettre de determiner les especes ligneuses qui, en
combinaison avec les graminees, pourraient aider a ameliorer l' alimentation
animale et partant a promouvoir le développement du sous-secteur de l' elevage.
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(Centre de recherches pour le developpement international), Ottawa (Canada). p. 52 a
77.
110
EFFET DE LA COMPLEMENTATION DEPANICUMMAXIMUM
AVEC DES FOURRAGES LIGNEUX SUR LA CROISSANCE ET
LE RENDEMENT EN CARCASSE D'OVINS
DJALLONKE MALES
T. Yo, BJ. Kouao, N.C. Bodji et G. Toure
Institut des savanes (IDESSA)
Departement Elevage
B.P. 1152, Bouake (Cote d' Ivoirc)
RESUME
Un essai a ete conduit pour determiner la valeur nutritionnelle de fourrages
ligneux dans 1' alimentation d' ovins Djallonke males. Quatre lots de moutons ont
6te soumis pendant 90 jours a quatre rations composees de Panicum maximum
pur (ration 1) ou complements avec Pterocarpus erinaceus (ration 2), Bridelia
ferruginea (ration 3) ou du tourteau de coton (ration 4).
Le GMQ des animaux soumis au Panicum maximum uniquement
s' etablissait a 47 g. La complementation avec Pterocarpus ou Bridelia
n' entratnait aucun accroissement significatif du GMQ, les chiffres enregistres
etant respectivement de 43 et 51 g. En revanche, la complémentation avec du
tourteau de coton se traduisait par une augmentation significative du GMQ
(88 g) et un bilan economique positif. Enfin, les rendements carcasse n'etaient
pas statistiquement differents, avec des moyennes de 51,2%, 49%, 51,9% et
52,1% pour les animaux soumis respectivement aux rations 1, 2, 3 et 4.
ABSTRACT
Effect ofsupplementing Panicum maximum with fodder browses on growth
and carcass yield in male West African Dwarfsheep
A feeding trial was conducted to assess the nutritional value ofbrowse forages
for male West African Dwarfsheep. Four experimental diets consisting of
Panicum maximum alone (diet 1) or supplemented with Pterocarpus erinaceus
(diet 2), Bridelia ferruginea (diet 3) or cottonseed cake (diet 4) were fed to four
groups ofsheep for 90 days.
Anunals receiving Panicum maximum alone achieved an average weight
gain of47 glday. Supplementation with Pterocarpus or Bridelia did not
111
significantly improve daily weight gains, which averaged 43 and 51 g,
respectively. Supplementation with cottonseed cake significantly increased the
average daily weight gain to 88 g and resulted in satisfactory economical
results. Carcass yield was not significantly affected by type ofdiet with means of
51.2, 49, 51.9 and 52.1% for animals on diet 1, 2, 3 and 4, respectively.
112
EFFET DE LACOMPLEMENTATION DUNE RATION DE BASE
DE QUALITE MEDIOCRE PARALBIZIA ZYGIA SUR LE
COMPORTEMENTALIMENTAIRE ET LACROISSANCE
D'OVINS DJALLONKE
D. Bouchel, N.C. Bodji et BJ. Kouao
Institut des savanes (IDESSA)
Département Elevage
B.P. 1152, Bouaké (Côte d'Ivoire)
RESUME
L intérêt de la complémentation d' une ration de base de qualité médiocre par
Albizia zygia pour des ovins Djallonké en croissance a été testé dans un essai
d'alimentation en deux phases de 90 jours chacune. Les animaux avaient été
divisés en quatre lots. Au cours de la phase I, tous avaient reçu du foin de
Brachiaria ruziziensis offert ad libitum et 100 g de mélasse de canne par jour.
Les lots 2, 3 et 4 avaient reçu en complément respectivement 200 et 400 g de
tourteau de coton et 800 g de feuilles d'A. zygia par jour. Au cours de la phase II,
tous les animaux avaient été nourris sur pâturage artificiel avec 400 g de tourteau
de coton par jour. Au cours de la phase I, les gains moyens quotidiens (GMQ)
étaient de 0, 93, 113 et 31 g/j respectivement pour les lots 1, 2, 3 et 4. L' indice de
consommation était de 7,4, 6,9 et 21,3 kg de MS/kg de croît pour les lots 2, 3 et
4. Au cours de la phase II, les GMQ s' établissaient à 54, 40, 45 et 63 g pour les
lots 1, 2, 3 et 4 et n' étaient pas significativement différents. Sur l' ensemble des
deux périodes, les GMQ étaient de 27, 67, 80 et 48 g respectivement. L étude de
carcasse effectuée à l' issue des deux phases fait ressortir un effet de croissance
compensatrice sur le poids de la carcasse et le rendement carcasse. Quant à
l' étude économique, elle montre que la complémentation se justifiait, même dans
l' hypothèse d' un coût maximum pourA. zygia.
ABSTRACT
Effect ofsupplementing a poor quality base diet with Albizia zygia on feeding
behaviour and growth in Djallonké sheep
The effect ofAlbizia zygia as a supplement to a low quality feed was tested on
growing Djallonké lambs during two feeding periods of90 days each. The lambs
113
were divided into four groups. During Phase I, a base ration of Braehiana
ruziziensis hay wasfed ad libitum to all animals with 100 g/day ofcane
molasses. In addition, group 2, 3 and 4 were supplemented with a daily ration of,
respectively, 200 and 400 g ofcottonseed cake and 800 g ofAlbizia zygia.
During Phase II, all animals were put on grown pasture and received 400 g of
cottonseed cake daily. During Phase I, average daily weight gains were 0, 93,
113 and31 gfor groups 1, 2, 3 and 4, respectively, whilefeed intakes were 7.4,
6.9 and 21.3 kg dry matter/kg ofweight increasefor groups 2, 3 and 4,
respectively. There was no significant difference in weight gains during Phase II
with rates of54, 40, 45 and 63 g/dayfor groups 1, 2, 3 and 4, respectively. Over
both periods, the average daily gains were 27, 67, 80 and 48 gfor groups 1, 2, 3
and 4, respectively. Carcass evaluation at the end ofthe two phases showed an
effect ofcompensatory growth on carcass weight and yield. Feeding supplements
to growing Djallonké lambs was shown to be economically justified, even at a
the maximum cost ofAlbizia zygia.
INTRODUCTION
En Côte d' Ivoire, les ligneux interviennent largement dans l' alimentation des
troupeaux en élevage traditionnel et sont même commercialisés sur les marchés i
bétail (ovins, caprins) toute l' année dans les grands centres urbains (Bodji et
NT Guessan, 1989). Parmi ceux-ci, citons Albizia zygia, une légumineuse très
appétée et disponible toute l' année sur une grande partie du territoire. L analyse
bromatologique indique que cette espèce possède une bonne valeur nutritive
(0,50 UF/kg de MS et 136 g de MAD/kg de MS) (Bodji, 1989), raison pour
laquelle elle a éte choisie pour cet essai d' alimentation.
Celui-ci visait à:
• effectuer une étude comparative du comportement alimentaire et pondéral
des ovins Djallonké recevant une ration de base de qualité médiocre (foin
de Brachiaria) complémentée avec du fourrage d'Albizia zygia ou du
tourteau de coton;
• étudier le phénomène de la croissance compensatrice sur les animaux
soumis à différents régimes alimentaires; et
• mesurer les effets de la complémentation et de la croissance compensatrice
sur le rendement carcasse.
MATERffiLS ET METHODES
L' essai s' est déroulé à la station du département Elevage de l' Institut des savanes
(IDESSA) à Bouaké (Côte d' Ivoire) en deux phases de 90 jours chacune.
Il a été réalisé sur un total de 44 sevrons de race Djallonké, provenant d' un
même lot d' agneaux nés à la ferme de l' IDESSA du Foro Foro. Ceux-ci ont été
114
transportés sur la station pour les besoins de l' essai et ont été répartis en quatre
lots. Un animal est mort au cours de la période d' adaptation.
L âge moyen des sevrons au début de l' essai était de 110 jours. Les poids à
la naissance et les GMQ de la naissance au premier jour de l' essai étaient
homogènes.
En début d' essai, divers traitements ont été administrés à titre
prophylactique.
D s' agissait d' un traitement anticoccidien, d' un traitement antibiotique et
d' un traitement anthelminthique. Tous les animaux disposaient d' eau et de
minéraux (pierre à lécher) à volonté.
Phase I
Les ovins sont parqués en permanence dans des loges de 13 m sur 7 sur aire
bétonnée avec abri. La période d' adaptation a duré huit jours. Au cours de cette
phase, chaque lot recevait sa ration expérimentale (tableau 1).
Tableau 1. Composition des rations journalières (g/j/animal) par lot
Loti Lot2 Lot 3 Lot 4
Effectif initial 11 11 11 10
Foin ad libitum ad libitum ad libitum ad libitum
Mélasse (g) 100 100 100 100
Tourteau de coton (g) - 200 400 -
Albizia zygia (feuilles) (g) - - - 800
On trouvera au tableau 2 la composition chimique, les valeurs nutritives
moyennes des composantes de la ration et les résultats des tests de digestibilité
d'Albizia zygia in vivo.
Phase II
Les animaux étaient menés de jour au pâturage, lequel était constitué de cultures
fourragères de Panicum maximum Cl ou T58, ou de Brachiaria ruziziensis,
selon les disponibilités. Ils étaient reconduits au parc le soir, où ils recevaient
400 g de tourteau de coton.
Contrôle et détermination des données zootechniques
Le poids des animaux était contrôlé régulièrement par une triple pesée effectuée
à 24 heures d' intervalle en début et en fin d' essai et tous les 15 jours au cours de
l'essai.
115
Tableau 2. Composition chimique et valeurs nutritives moyennes des composantes des rations
Tourteau de
Foin Mélasse coton Albiziazygia
MS (%) 90 73,6 91,88 35,6
Cendres 8,60 12,77 7,35 4,08
MAT 5,48 4,76 45,16 21,84
CB 37,13 - 13,40 35,45
ENA(%deMS) - 82,20 32,47 37,50
MG - - 1,64 1,53
Ca 0,38 1,22 0£1 0,45
P 0,19 0,07 1,28 0,15
Mg 0,21 - 0,66 0£1
K 1,45 3,94 1,65 0,93
Si (insoluble
chlorhydrique)
- - - 0,03
dMO (%) 53,1' - - 49,5"
MAD (g/kg de MS) 23* 33 370 105'
UFL(kgdeMS) 0,56* 0,95 0,87 0,54*
"D' après Kouao (1988)
Les quantités d' aliments offertes et refusées étaient mesurées
quotidiennement. Le taux de matière sèche était déterminé toutes les deux
semaines pour les aliments offerts.
Les quantités de matière fraîche û'Albizia zygia offertes étaient constantes
tout au long de l' essai, soit 12 kg en bottes, de manière à faire consommer
environ 800 g de feuilles par animal et par jour. Les différences de
consommation étaient dues aux variations du rapport feuilles/branches dans les
bottes, les feuilles ayant toujours été consommées en totalité.
Une étude du rendement vrai des carcasses a été effectuée à la fin de chaque
phase. 3 et 6 animaux ont été abattus par lot respectivement pour les phases I et
II. Pour les deux phases, les animaux n' ont pu être tous abattus le même jour, ce
qui signifie^que la période de jeûne avant l' abattage n' était pas la même pour
tous.
Le coût de la complémentation a été évalué. Pour les fourrages ligneux, 20 à
30 bottes ont été pesées chaque jour pendant 9 jours, sur les marchés à bestiaux
de Bouaké. En tenant compte des prix pratiqués, une approche économique a pu
être élaborée.
Les données rassemblées ont été soumises à une analyse de variance et les
moyennes des traitements comparées à l'aide du test de Newman-Keuls.
116
RESULTATS
Consommation
Phase I
L'adaptation aux régimes alimentaires a été très rapide, sans aucun signe de
pathologie digestive ni diminution d' appétit. Les consommations de foin de
Brachiaria ruziziensis étaient très variables quel que soit le lot considéré
(tableau 3).Albizia zygia était très appété. Les taux de matière sèche (MS) étant
variables, les chiffres de consommation présentés au tableau 3 n' ont qu' une
valeur indicative. L ingestion moyenne à'Albizia zygia au cours de la première
phase était de 2,0 kg de MS/100 kg de PV ou 39,1 g de MS/P0,75.
La mélasse et le tourteau de coton étaient toujours consommés en totalité.
On trouvera au tableau 3 les chiffres de consommation moyenne par animal
et parjour en MS, en UFL (unités fourragères lait) et en MAD (matières azotées
digestibles).
Tableau 3. Consommation (*écart type) deMF (foin et ligneux), MS, UF etMAD par animal et
parjour
Seuil de
Loti Lot 2 Lot 3 Lot 4 signification
MF foin (g/j) 337,18*120,30 461,26*117,52 373,29*135,11 336,71*115,88 1%
MS foin (g/j) 303,47*108,3 415,14*105,77 335,96*121,60 303,04*104,29 1%
MF ligneux (g/j) - - - 802,07*90,09 -
MS totale (g/j) 3793=109 692*107 781*125 661*108 1%
UFL totales 0,24*0,06 0,46*0,06 0,57*0,07 0,40*0,06 1%
MAD totales (g/j) 9,38*2,60 79,95*2,50 146,16*2,85 39,23*3,95 1%
MAD/UF 39 173 256 98 -
Les indices de consommation (IC) en UFL/kg de gain de poids vif et en kilo
de MS par kilo de gain de poids vif sont présentés au tableau 4. L IC du lot 1 n' a
aucune signification zootechnique étant donné que la croissance des animaux de
ce lot était quasiment nulle au cours de cette période.
Phase II
La consommation au pâturage n' a pas été mesurée. Le tourteau de coton
(400 g/tête/j) était consommé en totalité par tous les animaux, y compris ceux
des lots 1 et 4. L adaptation au nouveau régime alimentaire s' est faite au bout de
trois jours sans le moindre accident digestif.
117
Tableau 4. Indices de consommation relatifs à la phase I de l'essai
IC kg de MS/kg
de croît
ICUFL/kg
de croîtUFLAj GMQ(kg)
Loti 0,24 0,00001 37 900 24 000
Lot 2 0,46 0,093 7,44 4,95
Lot 3 0,57 0,113 6,91 5,04
Lot 4 0,40 0,030 21,32 12,90
Evolution du poids
Les chiffres de gains moyens de poids vif (kg), de GMQ (g/j) et de gains moyens
quotidiens par quinzaine sont présentés aux tableaux 5 et 6 pour les deux phases.
Le ralentissement de la croissance entre les 135e et 165e jours correspond à une
période où les pâturages disponibles étaient de qualité médiocre en raison d' un
temps de repos insuffisant. Qui plus est, cette période a été marquée par une
rupture de stock de tourteau de coton de plus de 15 jours.
Tableau 5. Performances pondérales comparées (*écart type) des deux phases
Loti Lot 2 Lot 3 Lot 4
Seuil de
signification
Phase I
Effectifs à la fin
de la phase I
Poids vif initial
(kg)
Poids vif final (kg)
GMQ moyen (g/j)
Gain moyen de
PV(kg)
Phase II
Effectifs à la fin
delà phase II
Poids vif initial
(kg)
Poids vif final (kg)
GMQ moyen (g/j)
Gain moyen de
PV(kfi)
17,11*2,71
54*24
11 11 10
11,87*2,08 12,67*1,95 12,05*1,83 12,75*2,54 n.s.
12,37*2,30 21,03*2,59 22,19*19 15,49*2,90 P<0,001
6*9 93*12 113*16 31*8 P<0,001
0,01*0,77 8,36*1,04 10,14*1,40 2,75*0,75 P<0,001
12,37*2,30 21,03*2,59 22,19*2,92 15,4*2,90
24,57*2,36
40*21
4,82*2,16 3,60*1,90
26,01*3,48 21,27*3,48
45*13 63*18
4,06*1,16 5,70*1,66
P<0,001
P<0,001
n.s.
n.s.
118
Tableau 6. Gain quotidien moyen (g/j) par quinzaine au cours des deux phases
Quinzaine Loti Lot 2 Lot 3 Lot 4
1 -27*25 122*19 138*32 10*19
2 0*28 77*22 125*31 47*14
3 -5*32 177*20 107*25 18*14
4 3*20 75*23 110*43 12*22
5 7*18 67*37 84*45 44*38
6 13*30 98*40 107*36 47*37
7 28*42 16*40 25*11 11*35
« 60*57 49*31 4*54 74*11
y 117*54 71*43 106*22 102*32
10 22*49 32*43 41*47 61*74
h -5*34 -9*90 28*51 20*49
12 75*38 75*58 60*82 101*39
Etude des carcasses
Le rendement par rapport au poids vif n' est donné ici qu' à titre indicatif compte
tenu des conditions d' abattage signalées plus haut. Cela n' affecte en rien les
résultats relatifs au rendement vrai, exprimé par rapport au poids vif vide
(tableau 7).
Après abattage, on a noté la présence d' un liquide clair abondant dans le
péritoine chez deux animaux du lot 1, trois du lot 4 et un dans chacun des lots 2
et 3. Aucune lésion macroscopiquement visible n' a été observée sur les organes
internes. Chez trois animaux des lots 1 et 4 et un animal du lot 3, on a noté la
présence d' un liquide clair peritonéal ou pleural, avec des lésions localisées et
anciennes de pneumonie pour deux animaux du lot 1 et celui du lot 3.
Coût de la complémentation
Prix des compléments
Il ressort d' une enquête effectuée sur le marché des petits ruminants de Bouaké
que les bottes de ligneux étaient vendues à 50 FCFA l' après-midi, et les invendus
conservés jusqu'au lendemain matin où, la demande étant forte, ils étaient
vendus à 100 FCFA. La "fraîcheur" du produit ne semble donc pas essentielle.
Au cours de la saison sèche, les prix restent les mêmes. Certains ligneux (Albizia
zygia, Pterocarpus erinaceus), plus appélés par les ovins et caprins, étaient plus
appréciés par les acheteurs mais cela ne semblait avoir aucune incidence sur les
prix. Quelle que soit l'espèce botanique, le poids moyen des bottes était très
119
Tableau 7. Résultats des deux premiers abattages (*écart type)
Lot 1 Lot 2 Lot 3 Lot 4
Seuil de
signification
1 abattage
Poids vif avant
abattage (kg)
PV vide (kg)
Carcasse chaude (kg)
Rendement carcasse
(%)
Rendement vrai (%)
Gras (g)
Gras en % du poids
décarcasse
2' abattage
Poids vif avant
abattage (kg)
PV vide (kg)
Carcasse chaude (kg)
Rendement carcasse
(%)
Rendement vrai (%)
Gras (g)
Gras en % du poids
de carcasse
11,53*0,91 20,03*1,27 21,43*4,01 14,47*1,50 P<0,001
7,93*0,99 15,4*1,78 17,23*2,57 10,00*1,67 P<0,001
3,93*0,46 8,03*0,81 9,50*1,45 5,03*0,93 P<0,001
34,03*1,50 40,05*1,79 44,56*2,26 34,62*3,32 P<0,001
49,61*0,67 52,22*1,12 55,13*1,33 50,22*1,35 n.s.
82*32 167*58 267*153 133*58 n.s.
2,03*0,61 2,08*0,75 3,01*2,04 2,67*1,03
16,95*3,27 24,63*3,13 25,51*4,07 20,43*3,52 P<0,01
13,34*2,24 19,72*2,50 21,05*3,12 16,68*3,18 P<0,01
6,78*1,19 10,35*1,49 11,05*1,81 8,59*1,94 P<0,01
40,19*1,60 42,00*2,04 43,33*1,82 41,72*2,65 n.s.
50,82*1,32 52,48*0,93 52,39*1,23 51,28*2,76 n.s.
67*28 158*46 245*104 101*45 P<0,001
0,89*0,38 1,53*0,39 2,18*0,83 1,13*0,36 P<0,01
variable, allant de 1,2 à 3,6 kg. Sur la base du coût de 50 FCFApar botte, le coût
de la complémentation quotidienne par animal au cours de cet essai était donc de
18,4 FCFA. Il s' agit de l' hypothèse d' un coût maximum, car en élevage en
milieu paysan, le prix du complément est égal à celui de la main-d' oeuvre. A
raison de 640 FCFAparjour pour un ouvrier journalier, le prix de la
complémentation est inférieur à 18,4 FCFA au delà de 35 animaux, en admettant
qu' un ouvrier soit embauché spécialement pour ce travail.
Avec un prix départ usine du tourteau de coton de 30 FCEA/kg, le coût de la
complémentation pour les lots 2 et 3 était donc de 6,2 FCFA et 12,4 FCFApar
jour respectivement, transport non compris.
Coût de la complementation par kilo de gain de poids vif
Ces résultats ne sont que des indications de l' intérêt de la complémentation par
rapport au prix du kilo de poids vif (PV). Le tableau 8 donne le coût moyen pour
120
Tableau 8. Coût en FCFA de la complementation par kilo de gain de PVpour la phase I
Gain moyen de Coût de la
PV complémenanon Coût par kg de Gain total dû au
Lot (kg) par animal (b) gain de PV croît (a) X = a -
1 - - - - -
2 8,36 558 66,75 6688 6 130
3 10,14 1 116 110,06 8112 6996
4 2,75 1665 605,45 2200 535
chaque type de complément par kilo de poids vif. Le prix moyen de vente des
animaux sur pied étant de 800 FCFA par kilo de PV, la complémentation dans les
conditions de l' essai est toujours intéressante même si les performances sont
médiocres (lot 4), surtout si l' on sait que la croissance était nulle chez des
animaux du lot témoin, qui ne bénéficiaient d' aucune complémentation.
En ce qui concerne la consommation de tourteau, on constate que le lot 3
consommait 200 g de plus, soit une dépense supplémentaire de 6,2 FCFA par
jour, pour un GMQ plus élevé de 20 g soit un gain de 16 FCFA par jour. Les
200 g supplémentaires, bien valorisés par l' animal, sont donc économiquement
justifiés.
Le tableau 9 donne pour chaque lot le coût moyen de l' aliment
complémentaire par kilo de gain de poids vif pour la totalité de l' essai ainsi que
le gain dû au croît, diminué du prix du complément (Y).
Tableau 9. Coût en FCFA de la complementation par kilo de gain de PVpour les deux phases
Gain
moyen de
PV(kg)
Coût de la complémentation
Pour les
phases
Gain total
dû au croîtPour la
phase I
Pour la
phase II (b)
Coût par kg de
gain de PVLot let II Y = a-b
1 4,82 0 1116 1116 231,54 3 859 2 740
2 12,07 558 1 116 1674 138,69 9 656 7 982
3 14,33 1116 1 116 2 232 155,76 11464 9 232
4 8,56 1665 1 116 2 781 324,88 6848 4 067
Le tableau 10 donne le coût supplémentaire de l' aliment complémentaire et
le gain supplémentaire par jour dû à la différence de croît entre les lots sur
I'ensemble de l'essai. En ce qui concerne la phase I, la complémentation était
toujours économiquement justifiée; la complémentation avec 400 g de tourteau
en lieu et place de 200 g était également justifiée.
Une comparaison des tableaux 8 et 9 révèle que le gain dû au croît diminué
du prix de l' aliment complémentaire obtenu grâce à la phase de croissance
121
Tableau 10. Coût de la complementation et bénéfice supplementaire (FCFAIj) dû à la différence de
croît entre les lots sur l'ensemble de l'essai
Gain supplémentaire dû à la
Lot Coût du complément différence de croit
1 - -
2 3,1 32
3 6,12 46,7
_4 9^25 16^8
compensatrice (Y-X) est maximum pour le lot 4, même dans l' hypothèse du
coût maximum de l' aliment complémentaire au cours de la première phase.
DISCUSSIONS
Consommation
Les résultats de l' analyse de variance montrent que la consommation de MS de
Brachiaria ruziziensis variait significativement (P<0,001) en fonction du lot et
de la période.
Les consommations moyennes étaient significativement différentes pour
l' ensemble des lots (P<0,01). Les moyennes des lots 2 et 4 n' étaient pas
significativement différentes. Il n' y avait pas de différence entre les périodes.
Ces consommations étaient plus élevées, excepté pour le lot 1, que les chiffres de
3,12 à 3,73 kg de MS/100 kg de PV obtenus par Richard et al. (1985) au cours
de plusieurs essais d' alimentation avec des ovins Djallonké dont la ration était
complémentée. Berger (1979a) rapporte une consommation moyenne de 5 kg de
MS/100 kg de PV dans un essai d' alimentation où du foin de Brachiaria était
distribué en quantité limitée (350 g) avec un concentré ad libitum à base de
mélasse, de farine de riz et de tourteau de coton. Il a obtenu, avec cette ration, un
GMQ de 87 g après 90 jours d' essai.
Berger (1979a) a noté des indices de consommation (IQ de 12,4 à 23,3 kg
de MS/kg de croît et de 7,4 à 12,7 UF/kg de croît. Quant à Richard et al. (1985),
ils ont rapporté des IC de 9,5 à 11,4 kg de MS/kg de croît.
La transformation de la matière sèche s' opérait bien dans les lots 2 et 3; en
revanche, les performances du lot 4 étaient médiocres, ce qui indique qu'Albizia
zygia ne peut être considéré comme un complément intéressant pour la
production de viande.
Evolution du poids
Les différences entre les taux de croissance obtenus au cours de la phase I étaient
toutes significatives (P<0,001).
122
La croissance était pratiquement nulle chez les animaux du lot témoin, ce
qui montre que cette ration doit être évitée pour les périodes critiques sur le plan
alimentaire.
Les GMQ des lots 2 et 3 étaient acceptables car comparables à ceux
rapportés par certains auteurs chez des moutons Djallonké recevant une
complémentation après sevrage; ces chiffres allaient de 65 à 110 g/j (Charray et
N" Dri, 1981; Charray, 1984; Vallerand et Branckaert, 1975; Rombaut, 1980;
Bassewitz et al., 1988; Richard et al, 1985; Berger, 1979b).
Le GMQ du lot 4 était de 31 g, chiffre médiocre, qui correspondrait
néanmoins à une croissance moyenne en milieu villageois avec une alimentation
non complémentée (Rombaut cité par Vallerand, 1979). La complémentation
avec Albizia zygia avait donc permis d'obtenir une croissance modérée chez des
ovins nourris avec un aliment de qualité médiocre. Sesbania sesban utilisé
comme complément de la paille de tef (Eragrostis tef) a entraîné chez des ovins
un GMQ de 48 g (CIPEA 1986). Ademosun et al. (1985) ont obtenu un GMQ de
35 g pour une ration de base de Gliricidia et de Leucaena. Quant à Smith et van
Houtert (1987), ils ont rapporté un GMQ de 40,2 g avec des animaux qui
recevaient du Gliricidia et au Leucaena.
Au cours de la phase II, les lots 2 et 3 avaient présenté les croissances les
plus faibles tandis que le lot 4 présentait les meilleures performances.
Cependant, il n' y avait pas de différence significative entre les lots (P>0,05). On
remarque également que le lot 1 était le moins homogène avec ses variations
individuelles extrêmement importantes. Il semble qu' il n' y ait pas eu de
croissance compensatrice.
Sur l' ensemble des deux phases, la différence entre les lots était très
significative (P<0,001) (tableau 11). Les performances du lot 1, malgré la
deuxième phase, étaient demeurées très médiocres. Celles du lot 4 étaient
modestes mais le gain total de poids vif était presque double de celui du lot 1.
Tableau 11. Croissance et gain de poids vifpour les phases I et II
Seuil de
significationLoti Lot 2 Lot 3 Lot 4
GMQ (g/j) 27*11
Gain total de PV (kg) 4,82*1,92
67*9
12,07*1,64
80*11
14,33*1,93
48*11 P<0,001
P<0,0018,56*1,94
Etude des carcasses
Les poids vifs vides et les poids de carcasse étaient significativement différents
pour les deux abattages à P<0,001 et P<0,01 respectivement. A l' issue de la
phase II, il y avait une différence significative entre les lots 2 et 4 pour ces
paramètres au premier abattage mais pas au deuxième. L' effet de la croissance
compensatrice se retrouve donc au niveau de la production de viande.
123
Les rendements vrais étaient significativement différents au premier
abattage (P<0,01) et seul le lot 3 avait un bon rendement (55,1%)- Ginisty (1976)
rapporte un rendement vrai moyen de 54% pour un poids vif moyen de 16,75 kg;
Richard et al. (1985) donnent des rendements vrais de 53,75 à 56,6% pour des
ovins de poids vif vide compris entre 25 et 30 kg. Alors que les poids vifs vides
étaient toujours significativement différents (P<0,001), il n" y avait pas de
différence significative entre les lots pour le deuxième abattage: la phase de
croissance compensatrice influençait donc la conformation des carcasses.
Les quantités de gras (en grammes par carcasse ou en % du poids de
carcasse) n' étaient pas significativement différentes au premier abattage. On peut
donc penser que du point de vue nutritionnel, la phase I se caractérisait par des
apports permettant au mieux une bonne croissance, suffisante toutefois pour
permettre un bon engraissement. Pour le deuxième abattage en revanche, la
différence entre les états d' engraissement était significative (P<0,001) (gras en %
du poids de carcasse). On constate que plus le poids moyen au début de la phase
II était élevé, plus la quantité de gras était importante, ce qui correspond à une
augmentation des dépenses énergétiques par kilo de croît. La phase II, qui
correspondait donc uniquement à une croissance compensatrice pour les lots 1 et
4, serait une phase de croissance — engraissement — ou de finition pour les lots
2 et 3.
Le poids de gras augmentait surtout à partir de 18,20 kg de poids vif vide,
ce qui correspondait à un poids vif de 23 à 25 kg. C est donc à partir de ce poids
vif moyen que la transformation devenait moins efficace et que l' augmentation
du poids vif nécessitait une quantité d' énergie de plus en plus importante. Pour
Richard et al. (1985), le poids vif n' est pas lié au rendement vrai (à un poids
moyen de 27,75 à 29,25 kg). Il existait ici une liaison hautement significative
pour les deux abattages (r=0,803 et 0,620, respectivement pour le premier et le
second abattage), ce qui signifie que l' alimentation avait un effet favorable tant
sur le poids vif que sur la conformation. Le gain de poids vif était donc associé à
l' augmentation du rendement de carcasse.
Coût de la complimentation
Berger (1979b) et Ettien (1983), après des essais d' alimentation de 97 et 120
jours respectivement, rapportent pour le coût de divers concentrés pour 1 kg de
gain de poids vif des valeurs très variables, allant de 71 à 84 FCFA/kg pour le
premier et de 69 à 130 FCFApour le second. Alors que le coût de la
complémentation parAlbizia zygia était beaucoup plus élevé dans l' hypothèse du
coût maximum, le tourteau de coton avait permis d' obtenir un coût moyen,
malgré la qualité médiocre de la ration de base.
Justifiée du point de vue zootechnique, la complémentation par Albizia
zygia durant une période critique du point de vue alimentaire l'était également
sur le plan économique car elle se traduisait par une croissance compensatrice.
124
CONCLUSION
La complémentation avec Albizia zygia au cours de la phase I a permis aux
animaux de conserver un état physiologique suffisamment satisfaisant pour
mettre à profit une période plus favorable et enregistrer une bonne croissance
compensatrice. La différence avec le lot témoin est significative sur l' ensemble
des deux phases.
La complémentation avec du tourteau de coton à raison de 200 ou 400 g par
jour permettait d' améliorer nettement les performances.
L étude des carcasses effectuée à la fin de chaque phase de l' essai a fait
ressortir un certain effet de la croissance compensatrice sur les poids des
carcasses et surtout sur les rendements vrais.
Bien qu' Albizia zygia n' ait qu' une valeur nutritive moyenne, ce ligneux
était très bien consommé. Le coût de la complémentation par kilo de croît
montre que la complémentation est justifiée du point de vue économique, même
dans le cas d' un coût maximum avec Albizia zygia. La complémentation avec ce
ligneux a surtout permis d' atteindre le poids minimum de commercialisation de
20 kg de poids vif au cours de la phase II, ce qui n' a pas été possible avec le lot
témoin.
BIBLIOGRAPHIE
Ademosun A.A., Bosman H.E. et Roessen P.L. 1985. Essai d'alimentation sur la chèvre
naine guinéenne dans la zone soudanienne humide du Nigeria. In: Les petits
ruminants dans I'agriculture africaine. Publié sous la direction de R.T. Wilson et
D. Bourzat. Actes de la conférence tenue au CIPEA (Centre international pour
l' élevage en Afrique), Addis-Abeba (Ethiopie), 30 septembre—4 octobre 1985. CIPEA
Addis-Abeba (Ethiopie). p. 82 à 92.
Bassewitz H., Jacob U., Bath R., Disset A., Amidou T., Ouattara A. et Doues S. 1988.
Ranch ovin de Koutiénédougou: Expériences acquises en ranching avec le mouton
Djallonké en savane soudanaise au Nord de la Côte d' Ivoire. SODEPRA-CEIB,
Abidjan (Côte d' Ivoire). 36 p.
Berger Y. 1979a. Note technique: Alimentation à base de mélasse des agneaux sevrés
Djallonké. Document technique, CRZ n° 12 zoot., Centre de recherches zootechniques
de Minank.ro, Bouaké (Côte d' Ivoire). 11p.
Berger Y. 1979b. Bilan de trois années d' étude de la race ovine Djallonké en Côte
d' Ivoire. Document technique, CRZ n° 08 zoot., Centre de recherches zootechniques
de Minankro, Bouaké (Cote d' Ivoire). 14 p.
Bodji N.C. 1989. Les fourrages ligneux utilisés pour l'affouragement des ovins et des
caprins en Cote d' Ivoire: Valeur nutritive. In: Séminaire régional sur les fourrages et
I'alimentation des ruminants, N'Gaoundéré (Cameroun), 16-20 novembre 1987.
Etudes et synthèses de l' IEMVT n° 30. Institut d' élevage et de médecine vétérinaire
des pays tropicaux, Maisons-Alfort (France). p. 777 à 788.
125
Bodji N.C. et N' Guessan A.A. 1989. Les fourrages ligneux utilises pour l' affouragement
des ovins et caprins en Cote d' Ivoire: Inventaire. In: Seminaire regional sur les
fourrages et l' alimentation des ruminants, N'Gaoundere (Cameroun), 16-20
novembre 1987. Etudes et syntheses de l' IEMVT n° 30. Institut d'elevage et de
medecine veterinaire des pays tropicaux, Maisons-Alfort (France), p. 265 a 283.
Charray J. 1984. Le mouton nain d'Afrique de l'Ouest en Cote d' Ivoire. Ses
caracteristiques zootechniques et son interet dans la lutte pour l' autosuffisance
alimentaire. Document technique, CRZ n° 08/84 viande CE/IDESSA, Centre de
recherches zootechniques de Minankro, Bouake (Cote d' Ivoire). 28 p.
Charray J. et N' Dri A. 1981. Selection et amelioration des ovins et caprins de C6te
d' Ivoire. Rapport annuel 1980. CRZ n° 04 zoot., Centre de recherches zootechniques
de Minankro, Bouake (Cote d' Ivoire). 65 p.
CIPEA (Centre international pour l' elevage en Afrique). 1986. Rapport annuel 1985/86.
CIPEA Addis-Abeba (Ethiopie). 100 p.
Ettien AJ.B. 1983. Comparaison de deux rations de base et de deux aliments concentres
pour l' alimentation de jeunes agneaux Djallonke en croissance. Memoire de DAA
Ecole nationale superieure d' agronomic, Rennes (France). 81 p.
Ginisty L. 1976. Rapport d'activite du premier semestre. CRZ n° 12 zoot. Exp. ovins,
Centre de recherches zootechniques de Minankro, Bouake (Cote d' Ivoire). 19 p.
Kouao BJ. 1988. Digestibilite et etude de la valeur nutritive des aliments: Synthese des
resultats acquis de 1981 a 1988. Centre de recherches zootechniques de Minankro,
Bouake (Cote d' Ivoire).
Richard D., Bassinga A., Ickowicz A., Cloe L., Pugliese L., Zungrana M. et Chicoteau P.
1985. Essais d' alimentation de moutons au Burkina Faso. Institut d'elevage et de
medecine veterinaire des pays tropicaux, Maisons-Alfort (France). 106 p.
Rombaut D. 1980. Comportement du mouton Djallonke en elevage rationnel. Revue
d'élevage et de medecine veterinaire des pays tropicaux 33(4):427-431.
Smith O.B. et Van Houtert M.FJ. 1987. La valeur fourragere de Gliricidia septum. Revue
mondiale de zootechnie 62:57-68.
Vallerand F. 1979. Reflexions sur l' utilisation des races locales en elevage africain.
Exemple du mouton Djallonke dans les conditions physiques et sociologiques du
Cameroun. These de doctoral veterinaire, Ecole nationale superieure agronomique de
Toulouse (France). 242 p.
Vallerand F. et Branckaert R. 1975. La race ovine Djallonke au Cameroun: Potentialites
zootechniques, conditions d' elevage, avenir. Revue d'elevage et de medecine
veterinaire despays tropicaux 28(4):523-545.
126
PERFORMANCE OF WEST AFRICAN SHORTHORN CATTLE
GRAZING UNDER SHEANUT TREES IN THE GUINEA
SAVANNA ZONE OF GHANA
1 2 2 2
A K Tuah , K Osei-Amaning , D Adomako andE Boye-Frimpong
Department of Animal Science
University of Science and Technology
Kumasi, Ghana
2 Cocoa Research Institute of Ghana
Tafo, Ghana
ABSTRACT
West African Shorthorn cattle were grazed under sheanut trees on a research
station at Bole in the Guinea Savanna zone of Ghana. Animals were herded
during the day and kraaled at night, according to local practice. Performance
data collected so far indicate a mean calf birth weight of 14.4 kg (range
10-19.5 kg) and a mean calving interval of 429.2 days (range 314-702 days);
these results compare favourably with results from similar studies in the forest
belt. During the six-month rainy season, grasses growing naturally under shea
trees yield about 800 kg dry matter/ha, with a nitrogen content of 1.29% of dry
matter; based on this yield, the carrying capacity of the natural grassland in the
rainy season is one animal per 1.4 ha.
RESUME
Performances des taurins à courtes cornes d'Afrique occidentale élevés sous
l'arbre à beurre ou karité dans la zone de savane guinéenne au Ghana
Des taurins à courtes cornes d'Afrique occidentale ont eté élevés sous I'arbre à
beurre ou karité en station à Bole en zone de savane guinéenne au Ghana. Les
animaux paissaient la journée et etaient rassembles la nuit dans des enclos
conformément à la pratique dans cette région. Les données de performance
obtenues jusqu'ici indiquent que le poids moyen des veaux à la naissance etait
de 14,4 kg (intervalle de variation de 10 à 19,5 kg) et I'intervalle entre vilages
de 429,2 jours (intervalle de variation de 314 à 702 jours). Ces résultats etaient
meilleurs que ceux obtenus dans des etudes analogues effectuées en région de
127
forit. Au cours des six mois d'hivernage, la production de matiere seche de
l'herbe naturelle poussant sous couvert de karite était de 800 kg/ha—chiffre qui,
avec une teneur en proteines de 1,29% de la MS, donnait une capaciti de charge
d'un animalpour 1,4 ha.
128
INTENSIVE FODDER GARDENS FOR INCREASING FORAGE
AVAILABDJTY FOR SMALLHOLDER DAIRY PRODUCTION
IN HAI DISTRICT, TANZANIA
EJ Mtengeti, NA Urio and G IMlay
Department of Animal Science and Production
Faculty of Agriculture
Sokoine University of Agriculture
PO Box 3004, Chuo Kikuu, Morogoro, Tanzania
ABSTRACT
For a long time, scarcity of animal feed has been a major constraint to
smallholder dairy production in Hai District in the Kilimanjaro region of
Tanzania, where land shortage is a serious problem. Feed resources commonly
used are grass (cut and transported from the lowlands), crop residues and
agro-industrial byproducts. But the costs of transporting low quality feed from
the lowlands and of treating crop residues increase the cost of milk production.
Small backyard fodder plots have been used to provide additional feed, but these
plots have not been managed intensively, and their yields have been low.
From September 1989, studies on intensive fodder gardens were started at
four sites in Hai District; three grasses—Pennisetum purpureum (elephant grass),
Tripsacum laxum (Guatemala grass) and Setaria splendida (setaria)—were
planted alone or together with a legume, green leaf Desmodium (Desmodium
intortum), at each site. In the first year, total annual herbage yields (fresh weight)
from sole grass plots ranged from 48 to 254 t/ha; yields from grass-legume plots
were usually slightly higher. These results indicate that intensive fodder gardens
can increase forage quality and availability for smallholder dairy production in
land shortage areas.
RESUME
Accroissement du disponible fourrager grace aux vergers d'embouche en vue
de la petite exploitation laitière dans le district de Hai en Tanzanie
Les penuries d'aliments du betail constituent depuis de nombreuses annees un
obstacle majeur au developpement de la petite production laitiere dans le district
de Hai, dans la r&gion du Kilimandjaro en Tanzanie. Les graminees (en
129
provenance des basses terres), les residus de récolte et les sous-produits
agro-industriels sont les ressources alimentaires les plus utilisées dans cette zone
oil le manque de terre consume un problème extrimement serieux.
Malheureusement, les frais de transport de cefourrage de qualité médiocre et les
pais de conditionnement des residus de récolte grevent lourdement laproduction
laitiere dans cette région. Faute d'un mode de gestion intensif, la production des
petits vergers d'embouche mis en place autour des casespour accroitre la
production d'aliments du bitail demeure faible.
En septembre 1989, des etudes ont dimarré sur des vergers d'embouche sur
quatre sites du district de Hal A cet effet, trois graminees, a savoir Pennisetum
purpureum (herbe a elephant), Tripsacum laxum (herbe du Guatemala) et
Setaria splendida (setaria) ont ete sanées en culturespures ou en association
avec Desmodium intortum—une legumineuse—sur chaque site. Au cours de la
premiere annee, la production totale (poids vert) defourrage des parcelles
semees uniquement de graminees allait de48 a 254 t/ha; quant a celle des
parcelles a association graminées-légumineuses, elle itait généralement
légèrement plus élevée. Ces resultats montrent que les vergers d'embouche
peuventpermettre d'accroitre la qualité et la production defourrage a
I'intention des petits producteurs de lait des régions oil le manque de terre
constitue un sérieux problème.
INTRODUCTION
In recent years smallholder dairy farming in Hai District, Tanzania, has been
gaining momentum, not only as a supplier of a high quality food (milk) but also
as a major source of cash for farmers (Mdoe, 1985). A major constraint to this
flourishing industry is shortage of animal feed; most farmers own only small
farms (about 0.5 ha) around their homesteads, which they use to grow coffee,
bananas and vegetables. The problem will worsen as population pressure
increases and land becomes even scarcer.
Feed resources used by these farmers are grass and crop residues
transported from the lowlands, vegetable residues, weeds from banana/coffee
plots and sometimes agro-industrial byproducts (such as molasses). But the cost
of transporting cut grass and crop residues from the lowlands increases the costs
of smallholder dairy production, and because these feeds have only low nutritive
value, milk yields are low (Urio, 1987). Moreover, feeding weeds from
banana/coffee plots to animals can be dangerous because toxic fungicides and
pesticides are sprayed on the coffee plants.
Small backyard fodder plots have been used to grow additional animal feed,
but lack of intensive management has meant that the yields from these plots have
been low. Urio (1987) noted that increased production from backyard fodder
plots can be increased by improving agronomic practices, by including legume
species in pasture plots and through better supply of pasture seeds. And recently,
small-scale farmers in Hai district have been urged by livestock extension
130
advisers to manage their homestead fodder plots intensively, in the same way as
vegetable gardens, so as to improve fodder yield and quality: fodder plots that
are managed intensively in this way are termed "intensive fodder gardens".
This paper presents the encouraging first-year results from an on-going
study on intensive fodder gardens at four different sites in Hai District, Tanzania.
MATERIALS AND METHODS
Experimental plots were established at four research sites (Sanya juu,
Mowanjamu, Kashashi and Nronga) in September 1989; plot size ranged from
20 to 48 m , depending on the availability of land. Three grasses—Pennisetum
purpureum (elephant grass), Tripsacum laxum (Guatemala grass) and Setaria
splendida (setaria)—were planted from the end of September to mid-October
1989, alone or together with a legume, (Desmodium intortum cv Greenleaf). The
experimental design was a randomised complete block with two replicates. Grass
spacing was 1.0 x 0.5 m; the legume was sown in rows between the grass rows,
at a seed rate of 1.2 kg/ha. Manure was applied at Sanya juu (8 t/ha) and Nronga
(10 t/ha) before planting. Urea was applied at Mowanjamu (70 kg N/ha) one
month after planting. No manure or fertiliser was applied at Kashashi. Plots were
weeded continuously during fodder establishment.
Elephant grass was harvested when it was about 1 m high, Guatemala grass
and setaria at about 0.75 m. Guatemala grass and setaria were cut at 15 cm above
ground level; elephant grass was cut at almost ground level so as to get strong
tillers and maintain the productive lifespan of the grass. Three cuttings were
made between January and June 1990, except at Sanya juu where only two
cuttings were possible due to late onset of the long rains. After cutting, the grass
and legume were separated and weighed to determine the fresh-weight yield.
Routine management of the experimental plots was done by farmers;
planting, cutting and weighing were undertaken jointly by researchers, farmers
and extension staff.
RESULTS AND DISCUSSION
Results for each site are presented in Table 1. Yields of grass or grass-legume
mixture were highest from elephant grass plots and lowest from Guatemala grass
plots. The legume gave the highest yield when mixed with Guatemala grass and
the lowest when mixed with elephant grass. The shading effect of the elephant
grass appears to hinder the growth of the legume.
With the exception of elephant grass at two sites and setaria and Guatemala
grass at one site each, total herbage yield was slightly (but not significantly)
higher from grass-legume mixtures than from sole grass plots. It has been shown
that elephant grass is at a competitive disadvantage with Desmodium intortum
under regular defoliation (Tiley, 1989). However, in this case the decline in yield
131
Table 1. Mean yields ofgrass and grass/legume mixtures atfour sites in Hoi District, Tanzania,
1990
Mean fresh-weight yields (t/ha per year)
% change
Grass/legume mixture in total % legume
in theGrass
alone
herbage
Species Grass Legume Total yield mixture
Kashashi
Pennisetum purpureum 254.05 203.60 12.05 215.65 -15.10 5.59
Tripsacwn latum 85.80 81.90 26.10 108.00 25.87 24.17
Setaria splendida 98.50 140.00 25.40 165.40 67.92 15.36
Mowaryarai
Pennisetum purpureum 132.35 116.25 7.25 123.50 -6.69 5.87
Tripsacum latum 72.50 63.10 21.35 84.45 16.48 25.28
Setaria splendida 93.95 102.30 9.60 111.90 19.11 8.58
Nronga
Pennisetum purpureum 203.45 213.20 1.55 214.75 5.56 0.72
Tripsacum latum 47.80 48.70 18.10 66.80 39.75 27.1
Setaria splendida 96.65 90.45 11.80 102.25 5.79 11.54
Sanyajuu
Pennisetum purpureum 193.60 207.80 0.50 208.25 7.57 0.24
Tripsacum latum 81.10 56.90 9.00 65.90 -18.74 13.66
Setaria splendida 153.90 146.90 0.65 147.50 -4.16 0.44
at the two sites did not appear to be due to competition because the percentage of
legume in the mixture was low, and so the effect must have been caused by other
environmental factors.
Significant yield differences were found across the four sites. Although the
differences observed were partly attributed to site-specific factors, differences in
the level of management might also have contributed to the observed results.
CONCLUSION
These first-year results seemed very encouraging to the farmers who learned the
importance of backyard intensive fodder gardens. With intensive management,
the fodder gardens could produce enough fodder to improve the feed budget and
thus maintain high milk production throughout the year. The farmers also learned
other advantages of grass—legume mixtures, such as conserving labour by
harvesting two separate forages together, suppression of weed growth by legume
132
between grass rows and improving forage quality. An on-going economic
evaluation is looking at how the cost of milk production could be affected by
these fodder gardens. Meanwhile, the technology of grass-legume mixtures,
which was hitherto uncommon in the district, is spreading fast because of the
apparently obvious advantage of better quality feed.
REFERENCES
Mdoe N S Y. 1985 . An economic analysis of alternative dairy feed management systems
in Kilimanjaro highlands, Tanzania. MSc Thesis. University of Guelph, Ontario,
Canada.
Tiley G E D. 1989. Factors affecting the productivity of elephant grass. In: XVI
International Grassland Congress, 4—11 October 1989, Nice, France. Association
francaise pour la production fourragere (The French Grassland Society), Versailles,
France. p. 601.
Urio N A. 1987. Feed resources for dairy farmers in Kilimanjaro, Tanzania. In: Kategile
J A Said AN and Dzowela B H (eds), Animalfeed resources for small-scale livestock
producers. Proceedings of the second PANESA workshop, held in Nairobi, Kenya,
11-15 November 1985. IDRC-MR165e. IDRC (International Development Research
Centre), Nairobi, Kenya. pp. 167-173.
133
134
ANIMAL PRODUCTION SYSTEMS
BASED ON
CROP RESIDUES AND LEGUMES

INTERCROPSTYLOSANTHES EFFECTS ON MILLET YIELDS
AND ANIMALPERFORMANCE IN THE SAHEL
C Kouamé1 *, S Hoefs1, JMPowell1, D Roxas2 and C Renara3
International Livestock Centre for Africa (ILCA)
ICRISAT Sahelian Center
BP 12404, Niamey, Niger
nJniversity of the Philippines at Los Barios
College Laguna, Philippines
^ternational Crops Research Institute for the Semi-Arid Tropics (ICRISAT)
ICRISAT Sahelian Center
BP 12404, Niamey, Niger
*Present address
Institut des savanes
BP 633, Bouak£, C6te d' Ivoire
ABSTRACT
The increasing interest in crop-livestock integration in sub-Saharan Africa has
emphasised the beneficial uses of forage legumes in cereal-based cropping
systems. Forage legume-cereal cropping systems were evaluated in 1989 and
1990 at the ICRISAT (International Crops Research Institute for the Semi-Arid
Tropics) Sahelian Center along with the performance of sheep fed millet residues
as a basal diet and supplemented with forage legume hay.
Intercropping Stylosanthes fruticosa (Retz.) Alston and S. hamata (L.) Taub.
with millet (Pennisetum glaucum [L.] R. Br.) did not significantly affect grain
yields during the legume establishment year. During the second year, when
millet was planted into pre-established stylo, total biomass and crude-protein
yields increased by 45 and 125%, respectively, yet millet grain yield decreased
by more than 30%. Sheep supplemented with 500 g stylo hay per day
consistently gained weight during 60-70 day pen-feeding and grazing trials.
Management strategies are needed to fully exploit the agronomic benefits
and feeding value of forage legumes introduced into Sahelian mixed fanning
systems.
137
RESUME
EJfet de I'introduction de Stylosanthes dans les systèmes agraires du Sahel sur
la production de mil et les performances animales
L'interet croissant que suscite I'intégration de I'agriculture et de I'élevage en
Afrique subsaharienne apermis defaire ressortir les avantages de I'introduction
des legumineuses fourragères dans les systèmes agraires a base de cereales. Des
systèmes agraires associant cultures de legumineuses et de cereales ont été
evalues en 1989 et 1990 au Centre sahélien de I'ICRISAT (Institut international
de recherche sur les cultures des zones tropicales semi-arides). Ces etudes
avaient ete effectuees simultanement avec des travaux visant a examiner les
performances d'ovins soumis a un aliment de base compose de residus de mil et
complementé avec dufoin de legumineuses.
L'introduction de Stylosanthes fruticosa (Retz.) Alston et de S. hamata (L.)
Taub entre les rangees de mil (Pennisetum glaucumj n'avait aucun effet
significatifsur la production de grains au cours de I'année a"etablissement des
legumineuses. Au cours de la seconde annee, lorsque le mil emit seme entre ces
legumineuses, les productions de biomasse totale et de protiines brutes avaient
augments de 45% et de 125% respectivement, alors que le rendement en grains
du mil avait baisse de plus de 30%. Des ovins soumis pendant 60 d70jours a un
regime d! alimentation a I'auge et depâturage lejour complementdpar 500 g de
foin de Stylosanthes enregistraient des gains reguliers depoids.
Des efforts doivent etre deployes pour élaborer des methodes de gestion
permettant de tirer pleinementparti des avantages agronomiques et nutritionnels
de I' introduction des legumineuses fourragères dans les systèmes agraires mixtes
du Sahel.
INTRODUCTION
The introduction of forage legumes in cereal-based cropping systems is a
promising strategy for increasing crop and livestock productivity in sub-Saharan
Africa (Gryseels and Anderson, 1983; Tothill, 1986). Forage legumes can
enhance soil fertility, improve yields and nutritive value of harvested products,
sustain food production and combat erosion (Mohamed-Saleem, 1985;
le Houerou, 1989; Izaurralde et al, 1990; Garba and Renard, 1991). However, the
beneficial effects of legumes vary according to crop species, management and
environmental factors (Waghmare and Singh, 1984; Nnadi and Haque, 1988;
Varvel and Peterson, 1990). Because forage legumes do not contribute directly to
food security, farmers are reluctant to devote land and other resources solely to
forage production. The adoption of forage crops by farmers will, therefore,
depend on the demonstration of their productivity and subsequent positive
impact on cereal and livestock production, The following studies were conducted
to determine the effect of forage legume-cereal intercropping on yields, nutrient
138
uptake and fodder quality, and performance of sheep fed cereal stover as a basal
diet and supplemented with forage legume hay.
MATERIALS AND METHODS
The studies were conducted during 1989 and 1990 at the International Crops
Research Institute for the Semi-Arid Tropic (ICRISAT) Sahelian Center (ISC), at
Sadore (latitude 13° 15' N, longitude 2° 18' E), Niger. The sandy soil (Siliceous
Isohyperthermic Psammentic Paleustalf) of ISC is acidic (pH 5.6 in 1:1
soil:water mixture) and low in native fertility (West et al, 1984). Average annual
rainfall is 560 mm; rainfall was 623 mm in 1989 and 499.5 mm in 1990.
Agronomic trials
Legumes for the intercropping trials were selected based on their previous
superior performance in screening evaluations. Seed of Stylosanthes fruticosa
(Retz.) Alston was collected locally and seed of S. hamata (L.) Taub. cv Verano
was obtained from the International Livestock Centre for Africa (ILCA), Addis
Ababa, Ethiopia. Seed of both species was multiplied at the ISC. The millet
(Pennisetum glaucum [L] R.Br.) cv CIVT, a recommended cultivar in the
region, was used. Experimental treatments consisted of two planting strategies:
millet and stylo sown on the same day
millet sown into year-old pre-established stylo;
and seven cropping patterns:
pure millet
pure S. fruticosa
millet plus S. fruticosa in alternate single rows
pure S. hamata
millet plus S. hamata in alternate single rows
millet plus S. fruticosa in alternate triple rows
millet plus S. hamata in alternate triple rows.
The treatments were replicated four times in a split plot design with
planting date assigned to the main plot and cropping system randomly assigned
to 8 x 12 m subplots. Each plot received an annual application of 13 kg P/ha as
single superphosphate which was broadcast before planting and worked into
ridges with an oxen-drawn plough after the first rains. Nitrogen was applied to
millet at the rate of 15 kg N/ha as calcium ammonium nitrate in a single
application about 30 days after emergence. Planting occurred on 30 June 1989
and 30 May 1990. Millet was sown in pockets at 1.2-m spacing on ridges 0.75 m
apart, and was thinned to three plants per pocket three weeks after sowing. Stylo
was sown in continuous lines and was not thinned.
To determine treatment effects on yields, the total biomass from the
innermost 3 x 4 m of each subplot was hand harvested and weighed. Millet was
139
fractionated into panicles, leaf (blade and sheath) and stem. Subsamples of millet
plant parts were sun-dried to constant weight for dry-matter (DM) determination.
Panicles were threshed to determine grain yield. The legumes were harvested
twice, approximately 60 and 120 days after emergence. Herbage subsamples
were oven-dried (75°C, 48 hours) for DM determination. Seed yields for the
legumes were determined at the second harvest. All plant samples were milled to
pass a 1-mm screen, acid-digested using a modification of the aluminium block
digestion procedure (Gallaher et al, 1975) and nitrogen and phosphorus were
determined by semi-automated colorimetry (Hambleton, 1977).
Analysis of variance using the General Linear Model procedures (SAS,
1982) was used to determine treatment effects on yields of millet grain and
stover, stylo herbage and seed and fodder crude protein. A least significant
difference (LSD) test (Montgomery, 1984) was used to identify possible
differences in treatment means.
Sheep feeding trials
A pen-feeding and a grazing trial were conducted in 1989 and 1990 to determine
liveweight changes of sheep fed millet stover as a basal diet and supplemented
with cowpea (Vigna unguiculata [L.] Walp.) or 5. fruticosa hay.
In the 70-day pen-feeding trial, three groups of eight intact male sheep
(average liveweight 28 kg) were randomly assigned to one of three rations:
1. millet stover only (control)
2. millet stover plus 300 g cowpea hay
3. millet stover plus 500 g stylo hay.
Millet was fed ad libitum and legume levels were determined to provide a
daily nitrogen supplement of 6 g per animal. The hays were offered individually
to animals at the end of the day.
In the 60-day grazing trial, 30 intact male sheep (average liveweight 25 kg)
were divided into three equal groups. All animals grazed a 3.5-ha millet field
during the day and the legume hays were offered individually to animals in the
evening at the same level as in the pen-feeding trial.
RESULTS AND DISCUSSION
Agronomy trials
Planting time and pattern highly influenced millet and stylo yields. During the
stylo seeding year, yields were highly variable and so no significant differences
in grain yields among the cropping systems were detected (Table 1). However,
average millet grain yields from the alternate triple row millet/5, hamata
treatment decreased by 78% in 1989. Millet stover yields were 10-53% less
from intercrops than from sole crops. Reductions were greatest in the millet/5.
140
Table 1. Seeding year yields ofmillet and Stylosanthes (millet and stylo sown on the same date)
as affected by cropping system
Millet Residue*
Cropping system
Grain
(kg/ha)
Stover
(kg/ha)
Stylo herbage
(kg/ha)
Biomass
(kg/ha)
Crude protein
(%)
1989
Pure millet 1080 2706 - 2706 4.3
Pure 5. fruticosa - - 213 213 11.9
Millet/5. fruticosai single rows 805 2405 14 2419 5.6
Pure 5. hamata - - 552 552 12.4
Millet/5. hamata single rows 1020 2428 22 2450 5.5
Millet/5. fruticosai triple rows 613 2400 327 2727 6.2
Millet/5. hamata triple rows 246 1276 353 1629 5.9
LSD (5%) ns 1181 123 948 1.7
1990
Pure millet 591 1960 - 1960 4.8
Pure 5. fruticosa - - 783 783 122
Millet/5. fruticosa: single rows 407 1484 202 1686 5.0
Pure 5. hamata - - 126 126 12.2
Millet/5. hamata single rows 414 1453 51 1504 5.7
Millet/5. fruticosa: triple rows - 539 1349 395 1744 7.5
Millet/5. hamata triple rows 341 939 61 1000 4.1
LSD (5%) ns 433 324 476 1.2
* Residue = millet stover + stylo herbage
hamata association. When millet was grown with S. hamata in alternate triple
rows, total biomass yield decreased by 40% in 1898 and 49% in 1990. Although
stylo intercropping reduced yields in some treatments, crude-protein content of
intercrop total biomass was 4—56% higher than that of sole millet crop in all
treatments, except in 1990 when stylo herbage yields in intercrops were very
low. Yet crude protein concentration of all harvested biomass was below 7%, the
minimum maintenance level for ruminants (Humphreys, 1978). This poor
feeding quality was due to the low stylo yield, probably caused by intermittent
drought and poor germination during the seeding year.
When millet was sown into pre-established stylo, grain yield was reduced
by 26-83% relative to monocrop millet (Table 2). Total biomass, crude-protein
and phosphorus contents of intercrops were, however, higher in both years than
those obtained in sole millet crop. Alternate triple row planting of millet with
either stylo resulted in lower millet grain yield in 1989 than alternate single row
141
Table 2. Yields ofmillet and Stylosanthes (millet sown into pre-established stylo) as affected by
cropping system
Millet Residue*
Grain Stover Stylo herbage Biomass Phosphorus Crude protein
Cropping system (kg/ha) (kg/ha) (kg/ha) (kg/ha) (%) (%)
1989
Pure millet 642 2662 - 2662 3.4 5.7
Pure 5. fruticosa - - 3075 3075 5.1 13.0
Millet/5. fruticosa
single rows
313 1214 2032 3246 4.6 9.3
Pure 5. hamala - - 1265 1265 1.7 122
Millet/5. hamata
single rows
276 1006 4698 5704 8.0 10.9
Millet/5 fruticosa
triple rows
106 618 2508 3126 5.4 11.1
Millet/5. hamata
triple rows
139 814 4122 4936 6.8 11.2
LSD (5%) 183 798 889 931 1.1 1.7
1990
Pure millet 832 3204 - 3204 1.5 2.9
Pure 5. fruticosa - - 2889 2889 4.6 12.2
Millet/5. fruticosa
single rows
429 2234 1518 3752 3.0 7.3
Pure 5. hamata - - 3936 3936 5.3 128
Millet/5. hamata
single rows
217 1286 3064 4350 4.4 9.5
Millet/5. fruticosa
triple rows
610 1845 1154 2999 2.8 6.2
Millet/5. hamata
triple rows
439 1308 2271 3579 3.9 8.5
LSD (5%) 112 787 429 652 1.0 1.0
* Residue = millet stover + stylo herbage
planting. Cropping patterns involving S. hamata reduced millet yields more than
those involving S. fruticosa.
Dry-matter yields of both stylos were greatest the second year after
establishment. Stylosanthes hamata produced significantly more herbage
(P<0.01) and assimilated more nutrients (P<0.01) than S. fruticosa. An exception
to this was lower pure S. hamata yields in 1989 due to plants being cut too short
142
the previous year, resulting in poor regeneration. Higher legume yields in the
second year versus the first year of establishment contributed to the increase of
intercrop dry-matter and crude-protein content but caused a decline of millet
yields.
Sheep feeding trials
For sheep grazing millet stover, average daily liveweight gains (ADG) for the
control, stylo and cowpea supplemented sheep were 78, 98 and 115 g,
respectively, during the first 22 days of the trial (Figure la). Unsupplemented
animals maintained their weight up to the 42nd day, after which they consistently
lost weight. Supplemented sheep continued to gain weight up to the end of the
trial. Average daily gains at the end of the trial were 12, 48 and 53 g for the
unsupplemented, stylo and cowpea supplemented sheep, respectively. Weight
gains of unsupplemented sheep during the first three weeks were probably due to
animals grazing selectively the more nutritious portion of the biomass such as
leaves, tillers and weeds. A parallel trial involving sheep grazing millet stover
and browse wind breaks (ILCA unpublished) found that crude-protein (CP)
content of millet residue dropped from 50 g CP/kg DM at the start of grazing to
39 g CP/kg DM after four weeks. The reason why unsupplemented sheep began
to lose weight, and weight gains of supplemented animals decreased after the
first three weeks of grazing, was probably a decrease in the nutritive value of
millet residues.
Pen-fed sheep consumed mostly millet leaves (blades and sheaths) and
refused most stems. Supplemented animals had steady growth rate throughout
the feeding period (Figure lb). Unsupplemented sheep gained weight for a week
and then maintained it up to 49 days, after which they lost weight up to the end
of the 70-day trial. Resulting ADG for the entire trial were -1.8, 78 and 51 g for
the control, stylo and cowpea hay supplemented sheep, respectively. That
supplemented animals consistently sustained growth rate throughout the trial
period was primarily due to constant nutritive value (53.1 g CP/kg DM) of feed
supplied in the basal diet.
CONCLUSIONS
There appear to be distinct tradeoffs in grain and feed output when millet and
stylo are intercropped. When millet was sown into year-old established stylo,
grain yield decreased but total feed biomass and protein yield increased as
compared with sole millet crop. The adoption of such intercropping systems will
depend on the relative emphasis placed by small-scale farmers on grain versus
feed production. The cut-and-carry system seemed to have an advantage over
grazing but this benefit would need to be weighed against other factors such as
labour input, storage, nutrient cycling, etc.
143
Figure 1. Effect of supplementing cowpea or stylo hay on liveweight of sheep grazing millet
stover (a) orfed millet stover in pens (b)
Millet stover (control)
• • Millet stover + 300 g cowpea hay
Liveweight (kg) x x Millet s,over + 500 9 sty,osanthes naY
32,
31 -
30-
28
27
26
25
24
/
-«-*-»-*
^
x—x
y \.
-i 1 1 1 1 1 1 1 1 r
Liveweight (kg)
35-
34-
X—X
33 - D x *
31
30
29
28
27
^~'■X
r
,x
_X
A~
/^x~x^ /
/
0 7 14 21 28 35 42 49 56 63 70
Days of feeding
144
la terms of improved feeding systems, the study showed that as little as 6 g
N in the form of stylo supplemented daily to sheep fed millet residue is enough
to obtain steady animal growth. The average additional 35 kg N/ha produced by
intercropping S. fruticosa with millet could, therefore, in theory provide
sufficient N supplement to 30 animals for 194 feeding days. Corresponding
millet stover yields could, however, be reduced. Appropriate management
strategies are therefore required to maximise the benefits of forage legume
introduction into mixed crop-livestock farming systems of the Sahel.
REFERENCES
Gallaher R N, Weldon C O and Futral J G. 1975. An aluminum block digester for plant
and soil analysis. Soil Science Society ofAmerica Proceedings 39:803-806.
Garba M and Renard C. 1991. Biomass production, yields and water use efficiency in
some pearl millet/legume cropping systems at Sadore, Niger. In: Sivakumar MVK,
Wallace J S, Renard C and Giroux C (eds), Soil water balance in the Sudano-
Sahelian zone: Proceedings ofInternational Workshop, Niamey, February 1991.
IAHS (International Association of Hydrological Science) Publication 199. IAHS
Press, Institute of Hydrology, Wallingford, UK. pp. 431-439.
Gryseels G and Anderson F M. 1983. Research on farm and livestockproductivity in the
central Ethiopian highlands: Initial results 1977-1980. ILCA Research Report 4.
ILCA (International Livestock Centre for Africa), Addis Ababa, Ethiopia. 30 pp.
Hambleton L G. 1977. Semiautomated method for simultaneous determination of
phosphorus, calcium and crude protein in animal feeds. Journal of theAssociation of
Official Analytical Chemists 60:845-852.
Humphreys L R. 1978. Tropicalpastures andfodder crops. Longman, London, UK.
135 pp.
Izaurralde R C, Juma N G and McGill W B. 1990. Plant and nitrogen yield of barley-field
pea intercrop in cryoboreal-subhumid central Alberta. Agronomy Journal 82:291-301.
le Houerou N H. 1989. The grazing land ecosystem ofAfrican Sahel. Ecological Studies
Vol 75. Springer Verlag, Berlin, Heidelberg, New York. 282 pp.
Montgomery D C. 1984. Design and analysis of experiments. 2nd edition. John Wiley and
Sons, New York, USA 418 pp.
Mohamed-Saleem M A 1985. Effect of sowing time on grain and fodder potential of
sorghum undersown with stylo in the subhumid zone of Nigeria. TropicalAgriculture
(Trinidad) 62:151- 153.
Nnadi LAand Haque 1. 1988. Forage legumes in African crop-livestock production
systems. ILCA Bulletin 30: 10-19. ILCA (International Livestock Centre for Africa),
Addis Ababa, Ethiopia.
SAS (Statistical Analysis Ssytems Institute Inc). 1982. SAS user's guide. SAS, Cary,
North Carolina, USA 1028 pp.
145
Tothill J C. 1986. The role of forage legumes in farming systems of sub-Saharan Africa.
In: Haque I, Jutzi S and Neate P J H (eds), Potentials offorage legumes informing
systems ofsub-Saharan Africa. Proceedings of a workshop held at ILCA, Addis
Ababa, Ethiopia, 16-19 September 1985. ILCA (International Livestock Centre for
Africa), Addis Ababa, Ethiopia, pp. 162-185.
Varvel G E and Peterson T A. 1990. Nitrogen fertilizer recovery in monoculture and
rotation systems. AgronomyJournal 82:935-938.
Waghmare AB and Singh S P. 1984. Sorghum-legume intercropping and the effects of
nitrogen fertilization. 1. Yield and nitrogen uptake by crops. ExperimentalAgriculture
20:251-259.
West L T, Wilding L P, Landeck J K and Calhoun F G. 1984. Soil survey ofthe ICRISAT
Sahelian Center, Niger, WestAfrica. Texas A&M University, College Station, Texas,
USA. 66 pp.
146
EFFECTS OF FEEDING HYDRATED TEFF STRAW AND
PROTEIN SOURCES ON TEFF STRAW VOLUNTARY INTAKE
AND GROWTH OF YOUNG HORRO SHEEP GRAZING NATIVE
PASTURE DURING THE DRY SEASON
Lemma Gizachew andAlemu Tadesse
Institute of Agricultural Research
PO Box 2003, Addis Ababa, Ethiopia
ABSTRACT
Two experiments were carried out to investigate the effects of supplementary
feeding on the dry-matter intake and growth rate of young Horro sheep grazing
native pasture during the dry season. In the first experiment, there was no
significant difference between the dry-matter intakes of ad libitum supplements
of dry or wetted teff straw (117 and 139 g/day, respectively). Neither dry nor
wetted teff-straw supplements significantly increased lamb growth rates in
comparison with unsupplemented controls (41, 40 and 37 g/day, respectively).
Lamb growth rates were, however, significantly increased by daily
supplementation with 238 g dry Leucaena per lamb, offered alone or with dry or
wetted teff straw (79, 69 and 78 g/day, respectively). In the second experiment,
feed supplements comprising different proportions of maize grain, noug cake
and dry Leucaena all significantly increased lamb growth rates above the
average of 10 g/day of unsupplemented controls. Growth rates of supplemented
lambs increased approximately linearly from 45 to 64 g/day as Leucaena
gradually replaced noug cake as the source of crude protein in the supplement.
These results demonstrate that home-grown Leucaena supplements can
improve the productivity of small ruminants during dry periods when feed
supplies are limited.
RESUME
Effet dun aliment complémentaire compost de paille de tefhydratee et des
sources de proteines sur Vingestion volontitire de paille de tefet la croissance
d'agneaux Horro élevés sur paturage naturel au cours de la saison sèche
Deux expériences ont && effectuées en vue d'evaluer I'effet d'un aliment
complementaire sur I'ingestion de matière seche et la croissance d'agneaux
147
Horro éleves sur paturage nature I cut cours de la satson sectie. Dans la premiere
experience, aucune difference significative n'a ete enregistrée entre la
consommation de matiere seche d'un complement de tefoffert ad libitum, qu'il
soit sous forme sechee ou hydratee, les chiffres etant delll et 139 g
respectivement. Par ailleurs, lapaille de tef, qu'elle soit sechee ou hydratée,
n'entrainait aucune accéleration significative de la croissance des agneaux,
laquelle s'etablissait à 41 et 40 g/j respectivement contre 37 g/jpour le lot
temoin. En revanche, un complément de 238 g de Leucaena par jour etpar téte
offert seul ou associe adela paille de tefséchee ou hydratee entrainait une
augmentation significative des taux de la croissance, les gains depoids etant
respectivement de 79, 69 et 78 g/j.
Dans la seconde experience, des aliments complementaires composts de
differences combinations de grains de mats, de tourteau de noug et de fourrage
de Leucaena seche entrainaient chez les agneaux des accroissements significatifs
des taux de croissance superieurs à la moyenne delO g/j enregistree chez les
témoins. Les gains depoids des agneaux augmentaient de maniere lineaire de 45
à 64 g/j à mesure que le Leucaena remplacait le tourteau de noug comme source
deproteine dans I'aliment complementaire.
Ces resultats montrent qu'une complementation de Leucaena, legumineuse
poussant sur place, peut permettre d'accrottre la productivity des petits
ruminants au cours de la saison seche, e'est-à-dire en periode de penuries
d' aliments du betail.
148
SUSTAINABLE DRY-SEASON FEEDING OF RUMINANTS IN
GHANA: THE USE OF CROP RESIDUES AND LEGUMINOUS
SHRUBS AS FEEDSTUFFS
KAmaning-Kwarteng
Agricultural Research Station, Legon
University of Ghana
Legon, Ghana
ABSTRACT
Ruminant livestock production in Ghana is based predominantly on native
grassland. The nutritive value of the natural pastures varies drastically according
to season: protein content is between 8 and 12% of DM at the start of the rainy
season but drops to 2-4% in the four- to six-month dry season. Animal
performance fluctuates widely, and there is overwhelming evidence of
undernutrition and malnutrition in the animals.
About 2.3 million tonnes of cereal crop residue are produced in Ghana
annually. If it is used strategically, this feed resource could save up to 186
million kg of livestock weight loss during the 120-day dry season.
Research work is underway on methods of transforming fibrous feeds into
adequate feed resources for ruminants in the dry season. For example, animals
fed urea-ensiled straw either maintained their liveweight or made modest
positive weight gains. When supplemented wilhLeucaena leucocephala (15 to
30% of total DM intake) liveweight gains in goats fed urea-treated rice straw
rose from 33 to 61 g/d over 56 days. It is suggested that feeding urea-treated
low-quality roughages supplemented with leguminous browses is the key to
solving dry-season feeding problems for the smallholder livestock farming
system in Ghana.
RESUME
Alimentation des ruminants pendant la saison sèche au Ghana: utilisation des
residus de récolte etdu fourrage des tegumineuses arbustives dans les rations
L'élevage des ruminants au Ghana repose essentiellement sur la production des
pâturages naturels dont la valeur nutritive varie tres sensiblement enfonction de
la saison. Ainsi la teneur en protéines de I'herbe naturelle varie de8al2%de la
149
mature seche au debut de I'hivernagepour chuter a 2 a 4% au cours des quatre
a six mois de saison seche. Les performances animales flue tuent done tres
largement et la sous-nutrition ainsi que la malnutrition semblent tres répandues
chez les animaux.
Environ 2,3 millions de tonnes de résidus de cereales sontproduites chaque
année au Ghana. Utilisee de maniere rationnelle, cette production peut
permettre d'eviter chez les animaux despertes depoids evaluees a 186 millions
de kilos depoids vifau cours des 120jours de secheresse.
Des travaux sont actuellement en cours sur la transformation des aliments
fibreux en ressources alimentaires utitisables par les ruminants au cours de la
saison seche. Par exemple, on s'est apercu que des ensilages depaille traitee
avec de l'uree permettaient aux animaux de maintenir leurpoids ou méme de
I'augmenter legerement. Par ailleurs, une complémentation de Leucaena
leucocephala (15 à 30% de la quantite totale de matiere seche ingérée)
entrainait un accroissement des gains depoids de33 a 61 g/j pendant 56 jours
chez des caprins nourris avec de lapaille de riz traitee avec de I'urée.
L'utilisation defourrages grossiers de qualite mediocre traites avec de I' uree et
complementers avec dufourrage de legumineuses ligneuses pourrait done
permettre de resoudre leproblème des pénuries alimentaires auquelsont
confrontes au cours de la saison seche les petits ileveurs au Ghana.
150
COLOPHOSPERMUMMOPANE BROWSE PLANTAND
SORGHUM STOVERAS FEED RESOURCES FOR RUMINANTS
DURING THE DRY SEASON IN BOTSWANA
JMacala1, B Sebolai1 andRR Majinda2
Department of Agricultural Research
Animal Production Research Unit
Private Bag 0033, Gaborone, Botswana
department of Chemistry
University of Botswana
Private Bag 0022, Gaborone, Botswana
ABSTRACT
Livestock in Botswana depend on natural rangelands for feed during both wet
and dry seasons. Indigenous browse plants providing feed for livestock include
leguminous types such as Acacia nilotica and nonleguminous types such as
Colophospermum mopane. The mopane tree has long roots which enable it to
extract moisture at great depth: because of this ability the plant breaks dormancy
and produces fresh green leaves before the rainy season. During the dry season
and drought years, mopane trees bear pods with seeds and these, together with
the dry mopane leaves, are consumed by livestock.
Cereal stovers are used to feed livestock during the dry season in certain
areas of Botswana. Because cereal stovers are low in crude protein, digestible
energy and mineral content, livestock farmers grow lablab (Lablab purpureas), a
legume fodder crop, to feed in association with crop residues in the dry season.
A dietary selection study on goats showed that the crude-protein content of
the plant material browsed in May, June and July was about 11.5%, compared
with about 9% in August. The average dry matter of the plant material browsed
in June, July and August was 93% compared with 84% in May. Liveweights of
animals dependent on browse plants during the dry season remained constant.
Differences in the apparent digestibilities of dry matter, crude protein and
organic matter found in a nutrient digestibility study with goats were highly
significant (P<0.001). There was a wide variation in the feed value of the dry
mopane leaves offered to the animals.
Fresh green mopane leaves contain more polyphenolic compounds and
condensed tannins than dry mopane leaves.
151
Average liveweight change and daily gain for steers fed sorghum stover
with lablab hay were higher (P<0.001) than those of steers fed sorghum stover
alone or with dry mopane leaves. The average cold dressed weight for Bonsmara
steers fed stover with lablab hay was higher (P<0.05) than for Bonsmara steers
fed stover alone or stover with mopane leaves. The poor performance of steers
fed stover with dry mopane leaves could be due to poor condition of the plant
material and/or to using steers that were not used to browsing the mopane plant.
RESUME
Utilisation defourrage de Colophospermum mopane etdepaiUe de sorgho
dans I'alimentation des ruminants au cours de la saison seche au Botswana
Que ce sou au cours de I'hivernage ou pendant la saison seche, I'essentiel des
aliments du betail utilises au Botswana proviennent des ressources pastorales
natureUes. Les especes ligneuses locales qui entrent dans I'alimentation du
betail sont, entre autres, des légumineuses (exemple: Acacia albidaj et d'autres
especes vegétales comme Colophospermum mopane. Avec ses longues racines,
ce ligneuxpeut ailer chereher I'eau a des profondeurs insoupconnees, ce qui lui
permet d'éviter lephénomene de dormance et de produire des feuilles vertes
avant le debut de la saison des pluies. Au cours de la saison seche,
Colophospermum mopane pone des gausses avec des graines, lesquelles sont
consommeespar les animaux au mime litre que les feuilles mortes.
Lapaille de céréales entre également dans I'alimentation des animaux
d'elevage dans certaines regions du Botswana. Etant donné que lapaille est
pauvre en proteines brutes, en énergie digestible et en matteres minerales, elle
est complemented en saison sechepar du foin de Lablab purpureas, une
légumineuse cultivée surplace par les éleveurs.
Des analyses ont revéle que le taux de proteines brutes des ligneux broutes
par les caprins etait d'environ 11,5% en mai, juin etjuillet contre 9% en aout.
Quant a leur teneur en matiere seche, elle etait en moyenne de 93% enjuin,
juillet et aout contre 84% en mai Les animaux se nourrissant de ces ligneux au
cours de la saison seche parvenaient a maintenir un poids relativement constant.
Une etude de digestibilite des élements nutritifs effectuée sur des caprins a
permis de mettre en evidence des differences hautement significatives (P<0,001)
entre les taux de digestibilite apparente de la matiere seche, les teneurs en
proteines brutes ou les taux de mattere organique. Par ailleurs, d'importantes
differences ant ete enregistrées dans la valeur nutritive des feuilles seches de
Colophospermum mopane.
De méme, les feuilles vertes contenaientplus de composes polyphénoliques
et de tanins que les feuilles seches.
Les variations et les gains moyens de poids des boeufs soumis a un régime
compose de paille de sorgho complementée avec du foin de Lablab purpureus
étatentplus élevés (P<0,001) que ceux des animaux recevant de lapaille de
152
sorgho associee ou non à dufourrage de Colophospermum mopane. Chez les
boeufs Bonsmara, un régime compose depaille complémentée avec dufoin de
Lablab purpureus se traduisait par unpaids moyen de la carcasse refroidie
superieur (P<0,05) à celui associe a un regime constitue depaille complémentée
ou non avec desfeuilles de Colophospermum mopane. Les performances
médiocres liies a la complementation avec desfeuilles seches de
Colophospermum mopane pourraient s'expliquer par lepietre etat du materiel
végetal utUisé et/ou lefait que les boeufs de cette experience n'avaient gutore
I'habitude dufourrage de Colophospermum mopane.
INTRODUCTION
There are several species of indigenous trees in Botswana which provide feed for
both game and livestock, especially during dry seasons and drought years.
Browse plants provide the bulk of the protein, vitamins and mineral elements
which are normally lacking in grasses during the dry season (le Houérou, 1980).
Colophospermum mopane trees, which have formed a distinctive vegetation
in the mopane veld area, provide feed for livestock during dry seasons and
drought years. Livestock browse mopane leaves when they turn reddish-brown
in colour, at which time their crude-protein content averages about 11%. Fresh
green mopane leaves have higher crude-protein content (almost 13%) but they
are not eaten as readily by livestock as the reddish-brown leaves. Fresh mopane
has low pH (4.83-5.05) and a bitter taste, which might contribute to its low
acceptability by livestock (Ernst and Sekhwela, 1987). Furthermore, during the
time when the mopane leaves are still green, natural grasses are abundant, and
livestock prefer to graze rather than browse. Also, antinutritional factors such as
tannins and polyphenolics may be present in high concentration in fresh mopane
and may reduce its intake by livestock. Polyphenolic compounds and tannins in
browse affect intake, digestibility and animal performance by reducing
degradation of fibre and protein by rumen micro-organisms.
During the dry season C. mopane plants bear pods with seeds which contain
15-16% crude protein and are readily eaten by livestock. The mopane plant has
long roots which enable it to extract moisture at great depths. Because of this
ability, the mopane plant breaks dormancy and produces fresh green leaves
before the rainy season, and therefore provides fodder for ruminants during the
periods of grass shortage.
The importance of goats and cattle to Botswana's economy, and of browse
plants to these animals during the dry season and drought years, justifies
conducting studies to determine the nutritive value and goats' selection patterns
of browse plants. Utilisation of dry mopane leaves and lablab (Lablab
purpureus) hay as dry-season supplementary feeds for beef steers fed sorghum
stover was investigated. The objectives of the studies were to:
• assess antinutritional factors in fresh and dry mopane leaves
• determine the nutritive value of goats' diets
153
evaluate the effect of feeding dry mopane leaves with sorghum stover on
nutrient digestibility by goats
• evaluate the performance of beef steers fed sorghum stover with mopane
dry leaves or lablab hay as supplementary feeds during the dry season.
MATERIALS AND METHODS
The sorghum (Sorghum bicolor) stover used in the goat nutrient digestibility and
steer performance studies was obtained from Sebele Agricultural Research
Station fields: it was chopped through a l0-cm size screen using a forage
harvester, left on the fields for two weeks to dry, and then piled together to
prevent loss of nutrients through leaching. Fresh and dry mopane leaves were
hand picked from Lesego Government Research Ranch in north-east Botswana.
Lablab hay was grown and harvested from Sunnyside Research Station farm.
Experiment 1
A study of goat diet selection patterns was conducted at Lesego Government
Ranch. The ranch covers an area of about 3990 ha, of which two 200-ha
paddocks, each with a similar vegetation cover, were used for the experiment.
There are several varieties of browse plants on Lesego ranch, but its vegetation is
classified as mopane mixed tree and shrubland.
Four castrated male Tswana goats (average initial liveweight 62 kg), fitted
with an oesophageal fistula, were used in the study. One day before sampling,
animals were kraaled at 1 200 hours to starve them so as to increase their intake
of the browse plants during the sampling period. At 0800 hours on the day of
sampling, the fistula plugs were removed and each animal was fitted with a
collection bag around its neck. Sampling was done monthly for four months
during the dry season (May to August). At least two samples for each goat were
collected each month. Sampling time was about 30-40 minutes and this was
preceded by removal of the sampled plant material from the collection bag into
plastic bags kept on dry ice to prevent further changes by plant enzymes. After
sampling the fistula plugs were refitted and the goats were transferred to the
paddock not used for sampling. The browsed samples for each individual goat
were freeze-dried, the ratio of browse plants/pods with seeds of the dried
browsed plants was determined, and the dried plant material was then ground
through a 1-mm screen for chemical analysis.
Experiment 2
A second study with goats was conducted to investigate nutrient digestibility.
Three groups of four Tswana goats (average initial liveweight 55 kg) were
randomly assigned to one of three diets:
154
• 540 g sorghum stover per day (diet 1)
• 407 g sorghum stover + 133 g mopane dry leaves per day (diet 2)
• 280 g sorghum stover + 260 g mopane dry leaves per day (diet 3).
The experimental regimen consisted of an ad libitum intake period of 18
days, followed by a five-day adjustment period to the feeding levels of the three
experimental diets.
Each animal also received (at 0800 hours each day) 260 g of concentrate
supplement containing 50% lablab leaves, 45% sorghum bran and 5% mineral
mix (dicalcium phosphate and salt (1:2)). The chemical composition of the
supplement was:
dry matter: 94.04%
crude protein: 13.35% of dry matter
• organic matter: 79.97% of dry matter
ash: 20.03% of dry matter
• crude fibre: 11.23% of dry matter
ether extract: 11.81% of dry matter
• nitrogen-free extract: 3.58% of dry matter
All animals were kept in metabolic crates during both the voluntary feed
intake and nutrient digestibility periods and were weighed at the start and end of
the experiment.
Weights and samples of feed offered and refused were taken daily during
the last seven days of the voluntary intake and nutrient digestibility period. Urine
and faeces were also collected daily from each animal during the digestibility
study. Samples of feeds offered and refused and of faeces were ground through a
1-mm screen and analysed for dry matter and nitrogen by standard methodology
(AOAC, 1980). Crude fibre was determined using a Fibertec System M (#1020
Hot Extrator). Ether extract was determined using the Soxtec System HT6
(#1043 Extraction Unit). Neutral and acid detergent fibre were determined on the
browsed plant material using the method of Goering and Van Soest (1970).
Lignin was determined using the 72% sulphuric acid procedure (Goering and
Van Soest, 1970). A quantitative analysis for polyphenolic compounds and
condensed tannins was done on both the fresh and dry mopane leaves using the
procedure outlined by Marini-Bettolo (1980).
Experiment 3
The effect of dry mopane leaves and lablab hay as supplementary feeds for beef
steers fed sorghum stover during the dry season is being evaluated in an
on-going study.
Three groups of three Tswana and three Bonsmara steers (average initial
liveweight 385 kg) were randomly assigned to one of three diets:
• 50% sorghum stover + 50% mopane dry leaves (diet 1)
70% sorghum stover + 30% lablab hay (diet 2)
sorghum stover alone (diet 3)
155
All animals were also offered dicalcium phosphate and salt (1:2) ad libitum.
The amount of feed offered to the animals was calculated based on the average
body size of the animals.
Animals were dipped every two weeks to control external parasites and
were weighed monthly. At the end of the experimental period (90 days) animals
were sent to the Botswana Meat Commission (BMC) for slaughter and the
carcasses were graded according to standard procedures.
Samples of feeds offered and refused were taken daily during the first seven
days of each month for a period of 90 days. The feeds were analysed for dry
matter and nitrogen by standard methods (AOAC, 1980). Neutral and acid
detergent fibre were analysed using the method described by Goering and Van
Soest (1970). Lignin was determined using the 72% sulphuric acid procedure
(Goering and Van Soest, 1970). In vitro organic matter digestibility was
measured using the Tilley and Terry (1963) procedure. The rumen fluid used in
the in vitro procedure was collected from two steers fed lablab and grass hay.
RESULTS
Experiment 1
The ratio of browsed plant material and pods with seeds found in the collection
bags of goats during the months of June and July was equal. The pods with seeds
were mainly ofDichrostachys cinera (Moselesele) and small quantities of
Acacia nilotica (Moka). Monthly chemical analyses of the browsed plant
material are presented in Table 1. Average dry-matter content of goats' extrusa
samples was lowest in May, while crude-protein content and in vitro organic
matter digestibility were lowest in August.
Table 1. Monthly chemical analysis ofplant material browsed by goats at Lesego Ranch
Chemical composition (% DM)
May June July August
Dry matter 84.00 93.00 93.00 93.77
Crude protein 12.00 10.98 11.49 9.07
Neutral detergent fibre 38.41 39.96 38.24 38.27
Acid detergent fibre 27.21 29.97 26.58 27.52
Lignin 12.03 12.45 11.09 11.99
Calcium 1.57 1.11 1.62 1.48
Phosphorus 0.18 0.27 0.18 0.20
In vitro organic-matter
digestibility
- - 58.25 45.23
156
Experiment 2
In the digestibility trial, substituting dry mopane leaves for stover increased the
crude-protein content and the total digestible nutrients of diets 2 and 3 over the
control diet (Table 2). The digestibilities of nutrients in goats fed diet 3 were
higher (P<0.001) than those in goats fed diet 1 or 2 (Figure 1).
The concentration of condensed tannins was higher in fresh than in dry
mopane leaves.
Average liveweights of the goats were 68 kg in May, 70 kg in June and July
and 67 kg in August.
Table 2. Chemical composition and total digestible nutrients of diets fed to goats in the nutrient
digestibility trial
Chemical composition (% DM)
Ingredients Diet 1 Diet 2 Diet 3
Dry matter 95.02 95.07 95.07
Crude protein 6.48 8.55 10.62
Organic matter 82.87 85.25 86.78
Ash 17.13 14.75 13.22
Ether extract 9.28 14.25 14.25
Crude fibre 2252 21.78 21.09
Neutral detergent fibre 4459 40.67 40.82
Total digestible nutrients 43.69 66.15 67.41
Experiment 3
The chemical analysis of the diets given to the animals is presented in Table 3.
Average daily dry-matter intakes were 31.17, 49.17 and 43.80 kg for
animals fed stover + mopane, stover + lablab hay and stover alone, respectively.
There were differences (P<0.001) in the liveweight changes and average daily
gains of the animals offered the experimental diets, and in the cold dressed
carcass weights of Bonsmara steers (P<0.05) (Table 4).
Two carcasses of steers that were fed stover alone and one carcass of a steer
fed stover and dry mopane leaves were condemned at BMC because of
cysticercus bovis.
DISCUSSION
The lower crude-protein and higher DM content obtained in browsed plants
sampled in August confirms that plant material deteriorates in quality as the dry
season progresses. Subsequently, the performance of animals dependent on this
157
Figure 1. Nutrient digestibility by diet
Digestibility (%)
100-1
I }i Dry matter Organic matter
iffiM Ether extract
Crude fibre
►,\tv, :::::::::::::
 
Diet 1 Diet 2 Diet 3
Table 3. Ingredients and chemical composition ofthe diets fed to steers
Chemical composition (% DM)
Ingredient Dietl Diet 2 Diet 3
Dry matter 93.76 93.44 93.52
Crude protein 7.86 10.06 5.57
Neutral detergent fibre 52.16 65.54 69.90
Acid detergent fibre 33.31 41.98 41.35
Lignin 6.38 6.00 4.80
In vitro dry-matter digestibility 45.1 59.46 49.15
plant material is affected. In the tropics, animals need a diet of 7% crude protein
and 45% dry matter digestibility to maintain their liveweight. Animals fed a diet
with the 10-11% crude protein and 55% DMD are expected to gain weight
(McDowell, 1972). In this experiment, the average liveweights of the goats
remained constant in May, June and July and dropped slightly in August. The
decrease in liveweight of the goats in August may be attributed to the decrease in
158
Table 4. Liveweight changes, daily gains and cold dressed carcass weights ofbeefsteers fed
sorghum stover + mopane leaves, stover + lablab hay and sorghum stover alone during
the dry season
Parameters Diet 1 Diet 2 Diet 3 SE
Initial mean liveweight (kg) 384 385 385 ns
Final mean liveweight (kg) 404 436 402 2Z0
Change in liveweight (kg) 18 51 17 6.66
Average daily gain (g) 200 566.7 188.2 52.65
Cold dressed weight (kg)
Tswana 166 168 158 ns
Bonsmara 168 191 168
crude protein and increase in DM of the plant material eaten by the goats. The
lignin content of the sampled plants during the dry season was similar and high.
Previous studies comparing the digestive efficiency of goats, sheep and other
ruminants have shown that goats are more efficient in digesting crude fibre
(Devendra, 1986; ILCA, 1988). The greater efficiency for goats to digest fibre is
associated with the intake of poor quality roughages, the feeding behaviour,
concentration of cellulotic bacteria and rate of feed movement along the
alimentary tract (Devendra, 1986).
Even though a significant increase in the digestibility of nutrients was found
in goats fed diet 3, this increase was due mainly to the high proportion of
concentrate supplement fed with the stover. There was a high degree of variation
in the crude-protein, calcium and phosphorus content in the dry mopane leaves
offered to the goats during the nutrient digestibility study (Table 5): this variation
may be due to picking mopane leaves that may be low in feed value even though
still attached to the plant. Mopane and other browse plants selected by the goats
during the dietary selection study had crude-protein contents higher than the 7%
suggested for liveweight maintenance (McDowell, 1972). This therefore
indicates that goats are able to select nutritious plant material. However, the
overall productivity of these animals dependent on browse plant during the dry
season can be improved by providing them with locally available supplementary
Table 5. Percentage crude protein, calcium andphosphorus o/Colophospermum mopane plant
offered to goats at Lesego Government Ranch during the dry season
Content (%DM)
Nutrient May June July August
Crude protein 10.53 9.01 9.23 8.97
Calcium 1.74 1.42 1.45 1.40
Phosphorus 0.19 0.15 0.14 0.14
159
feeds such as sorghum bran, sorghum chaff and a mineral supplement. The
higher concentration of condensed tannins in fresh than in dry mopane leaves
suggests that these antinutritional factors have a contributory effect on the intake
of fresh mopane leaves by animals. Research work on the quantitative and
qualitative analysis of both the fresh and dry mopane leaves is necessary in order
to make any recommendations on the efficient utilisation of the mopane plant for
livestock feeding during the dry season and drought periods.
The average daily gain of 0.566 kg obtained for steers supplemented with
lablab hay was due to the high intake of lablab hay and agrees with the results of
McDowell (1972) that animals given a diet with 10% crude protein and 55%
DMD can gain 03-0.6 kg per day. The high average liveweight change, daily
gain and cold dressed weight obtained with steers supplemented with lablab hay
was mainly due to the better performance of the Bonsmara animals; these
increased their liveweight by 21% compared to 12% for Tswana steers fed the
same diet. The better performance of Bonsmara cattle indicates mat animals with
a high genetic potential can perform better under improved management.
Utilisation of cereal crop stovers with lablab hay for cattle feeding in the dry
season is a new intervention which has been adopted by a number of livestock
farmers in Botswana, especially dairy producers. However, appropriate
technology for harvesting, conservation and utilisation of the lablab crop is
needed if it is to be used efficiently as a livestock feed.
It is generally accepted that tree forage improves livestock performance
when fed in combination with cereal residues (Agishi, 1988). However, in this
experiment, dry mopane leaves were poorly accepted compared with lablab hay.
The poor acceptance of the dry mopane leaves could have been due to poor
condition of the plant material and/or to using steers that were not used to
browsing the mopane plant. More research work is being planned with the
mopane plant and with other browse plants that provide fodder for livestock
during the dry season and drought years when there is no grass available for
livestock feeding.
REFERENCES
Agishi E C. 1988. Appropriate browse and other forage legumes for smallholder
production in West and central Africa. In: Proceedings ofthe workshop on the
improvement ofsmall ruminants in West and CentralAfrica, Ibadan, Nigeria, 21-25
November 1988. OAU (Organization of African Unity), Nairobi, Kenya. pp. 115-128.
AOAC (Association of Official Analytical Chemists). 1980. Official methods ofanalysts.
13th edition, AOAC, Washington, DC, USA. 1018 pp.
Devendra C. 1986. Small ruminant production systems. In: Proceeding ofthe workshop
on small ruminant systems in South and Southeast Asia, Bogor, Indonesia, 6-10
October 1986. IDRC (International Development Research Centre), Ottawa, Canada.
pp. 29-51.
160
Ernst WHO and Sekhwela M B M. 1987. The chemical composition of Lcrps from the
mopane psyllid Arytaina mopane (Homoptera, psyllidae). Insect Biochemistry
17:905-909.
Goering H K and Van Soest P J. 1970. Foragefiber analysis. Agricultural Handbook 379.
US Department of Agriculture, Washington, DC, USA 20 pp.
ILCA (International Livestock Centre for Africa). 1988. Small Ruminant Meat and Milk
Thrust. In: ILCA AnnualReport 1987. ILCA Addis Ababa, Ethiopia. pp. 17-34.
le Houerou H N. 1980. The role of browse in the Sahelian and Sudanian zones. In:
le Houerou H N (ed) Browse in Africa: The current state ofknowledge. ILCA
(International Livestock Centre for Africa), Addis Ababa, Ethiopia. pp. 83-100.
Marini-Bettolo, 1980. Preliminary chemical screening ofmedicinalplants infield
conditions. World Health Organization Report. World Health Organization, Geneva,
Switzerland.
McDowell R E. 1972. Improvement of livestockproduction in warm climates. Freeman
and Company, San Francisco, USA
Tilley J M Aand Terry R A 1963. Atwo-stage technique for in vitro digestion of forage
crops. Journal ofthe British Grassland Society 18:104-111.
161
162
THE USE OFLEUCAENALEUCOCEPHALA
SUPPLEMENTATION TO IMPROVE THE UTILISATION OF
MAIZE STOVER BY SHEEP
A E Kimambo, AMMakiwa andMNShem
Department of Animal Science and Production
Faculty of Agriculture
Sokoine University of Agriculture
PO Box 3004, Chuo Kikuu, Morogoro, Tanzania
ABSTRACT
Experiments were conducted to investigate the effect of Leucaena leucocephala
supplementation on the intake and rumen degradation of maize stover (Staha
variety) by sheep. A feed intake study on four levels of Leucaena
supplementation (0, 3, 6 and 9 g dry matter/kg liveweight per day) in a 4 x 4
Latin square design was undertaken. Dry-matter degradation of maize stover and
rumen ammonia concentration were measured using two Gstulated sheep fed the
four diets.
Total dry-matter intake of the supplemented diets was significantly (P<0.05)
higher than that of the unsupplemented diet. Daily dry-matter intake of maize
stover alone increased from 32.8 g/kg for the unsupplemented diet to 36.2 g/kg
for the diet containing the lowest level ofLeucaena supplementation. Higher
levels of Leucaena supplementation led to a decrease in the amount of maize
stover consumed.
Leucaena supplementation significantly (P<0.05) increased the rumen
degradation of maize stover at 48 hours of incubation compared to
unsupplemented maize stover.
Ammonia concentration in the rumen increased significantly (P<0.05) with
increase in the level ofLeucaena supplementation up to 6 g/kg per day. Higher
levels of Leucaena in the diet did not result in further increase in rumen
ammonia concentration. There was no change in the rumen pH for the different
levels oiLeucaena supplementation.
The results indicate that intake and rumen degradation of maize stover in
sheep could be improved by supplementing the animals with up to 6 g DM/kg
liveweight per day oiLeucaena hay. Higher levels of supplementation appear to
lead to substitution effects.
163
RESUME
Amélioration de I'utilisation de la paille de matspar les ovins grdce d une
complementation de Leucaena leucocephala
Des experiences one ete menees sur des ovins pour determiner l'effet dune
complementation de Leucaena leucocephala sur la consommation et la
degradation de la paille de mats (varieté Staha) dans le rumen. L' ingestion a ete
etudiee avec quatre niveaux de complementation de Leucaena (0, 3, 6et9 gde
matiere seche par kilo depoids vif etparjour) sur le modele d'un carre latin
d'ordre 4. La degradation de la matiere seche de la paille de mats et la
concentration de I'ammoniac dans le rumen ont ete mesures sur deux ovins
fistules alimentes avec les quatre rations.
L' ingestion total; de matiere seche etait significativement plus élevee
(P<0,05) avec la complementation. En ce qui concerne la paille au seulma'is, la
consommation journaliere de matiere seche avait augmenté de 32,8 g/kg/j pour
la ration non complementee a 36,2 g/kg/j pour la ration complementée contenant
le niveau leplusfaible de Leucaena. Des niveaux plus éleves de
complementation entrainaiem une baisse de la consommation de paille de mats.
Par rapport d la ration non complementée, iapport de Leucaena entrainait
un accroissement significatif (P<0,05) de la degradation de la paille dans le
rumen apres 48 heures d' incubation. La concentration d'ammoniac dans le
rumen augmentait significativement (P<0,05) avec I'accroissement au niveau de
Leucaena dans la ration et ce, jusqu'à 6 g/kg/j. Au-delà, I'augmentation du
niveau de complementation n 'entrainait plus aucun accroissemem de la
concentration d'ammoniac dans le rumen. LepH du rumen etait independant du
niveau de complementation de la ration.
Ces resultats montrent que I'on peut accroitre la consommation de paille de
mats et sa degradation dans le rumen des ovins en les soumettant a une ration
complementée avec jusqu'à 6 gde matiere sèche de foin de Leucaena par kilo de
poids vifpar jour. Des niveaux plus éleves entrainent des phenomenes de
substitution.
INTRODUCTION
Intake of straws and stover by ruminants is usually too low to maintain body
weight: tough texture, poor digestibility and nutrient deficiency all contribute to
the low level of consumption (El-Naga, 1989). These roughages are low in
readily available energy, carbohydrates and nitrogen, which reduces the
efficiency with which they are utilised by animals. Chemical treatment of straws
using sodium hydroxide (Urio, 1977; Kategile, 1979) or urea (Kiangi 1981;
Raymond, 1989) can improve both their digestibility and intake, but is not
always practical under farmer conditions. Thus alternative strategies to improve
straw utilisation have been sought.
164
Leguminous forages such as Leucaena leucocephala have been used to
improve dry-matter intake and digestibility of pasture hay by sheep (Bamualim
et al, 1984). Because of the increased interest in the use ofLeucaena spp as
protein supplements for ruminants, the present study investigated the effect of
various levels ofLeucaena leucocephala supplementation on the intake and
rumen degradation of maize stover by sheep.
MATERIALS AND METHODS
Experimental animals and feeds
Six Blackhead Persian sheep were used in the experiment. Four sheep, weighing
about 28 kg, were used for intake studies in a 4 x 4 Latin square. The other two,
weighing 33 kg and 41 kg, were fistulated and used for degradation studies.
Maize stover was obtained from harvested maize fields and chopped into
3-5 cm lengths. Leucaena leucocephala hay was obtained by cutting and wilting
leafy branches of the plant and threshing the branches to separate the leaflets (the
hay) from the twigs.
Intake studies
For the intake studies, the animals were confined in individual metabolic cages
and offered a known quantity of maize stover ad libitum twice a day at 0900 and
1600 hours. Each animal also received 200 g of maize bran and vitamin/mineral
mixture, alone or together with one of three levels of Leucaena hay supplement
(3, 6 and 9 g dry matter/kg liveweight per day), at the morning feeding. Each diet
combination was fed to each animal for 14 days, a seven-day preliminary period
and a seven-day data collection period.
Degradability of maize stover
Degradation of maize stover was investigated for each diet combination using
the nylon-bag technique (0rskov et al, 1980).
Maize stover was ground to pass through a 2.5-mm screen and 2-g samples
were weighed into 20 labelled nylon bags of known weight. For each ration, 10
bags were put into the rumen of each sheep and removed, two at a time, after 6,
12, 24, 48 and 72 hours of incubation. The removed bags were washed under
running tap water until the water was clear and the residues were dried in an
oven at 60°C for 48 hours, cooled in a desiccator and weighed. Dry-matter
degradability was calculated using the formula
weight ofDM incubated - weight ofdry residue
vcDMD = . . - _ _ _ . , . x 1UU
weight ofDM incubated
165
Rumen ammonia and pH
For rumen ammonia and pH determination, rumen liquor was obtained from the
fistulated animals during the data collection period for each level ol Leucaena
supplementation. The liquor was collected at 0600, 1000, 1400 and 1800 hours,
strained through cheese-cloth and centrifuged at 3000 rpm for 15 minutes, and
20-ml samples were taken for immediate pH determination.
For ammonia determination, 25-ml samples of the centrifuged rumen liquor
were treated with two drops of concentrated sulphuric acid and frozen to await
analysis. For the analysis, 5 ml of rumen liquor were mixed with 10 ml of 5%
sodium tetraborate solution. Two drops of mixed indicator were added and the
mixture was distilled using the kjeltec system. The distillate was collected in a
flask containing 25 ml of 20% boric acid, and titrated with 0.1213N HCl.
Ammonia concentration was calculated by
... 14.01 x {titre-blank) x norm ofHCl
%Ammoma-N *—;— *:———'
mis ofsample x 10
%Ammonia =Ammonia-Nx 1.21
% Ammonia was then converted into mg ammonia/litre.
Statistical analysis
Two-way analysis of variance for a Latin square design was used for intake
studies data, and one-way analysis of variance was used for other parameters,
according to Snedecor and Cochran (1980). The significance of the results was
tested using F test and LSD.
RESULTS
Dry-matter intakes (DMT) of the total ration roughage (maize stover plus
Leucaena) and of maize stover alone are shown in Table 1.
Total DM1 was significantly (P<0.05) increased by Leucaena
supplementation. Total DMI of ration B was significantly lower (P<0.05) than
that of ration D, but there was no significant difference between the DMI of
rations B and C or rations C and D.
Dry-matter intake of maize stover alone increased when the diet was
supplemented with 3 g Leucaena DM/kg liveweight per day, but further increase
in the level Leucaena supplementation led to a decline in the amount of maize
stover consumed.
Dry-matter (DM) and organic-matter (OM) degradabilities of maize stover
in the rumen of sheep fed the different rations are shown in Table 2. Leucaena
supplementation increased DM and OM degradability of maize stover at all
incubation times. The greatest increase was observed at the supplementation
level of 3 g Leucaena DM/kg liveweight per day. Statistical analysis of the DM
166
Table 1. Dry-matter intake of total roughage (maize stover and Leucaena supplement) and maize
stover alone for the four rations
Daily intake (g DM/kg liveweight)
Total roughage Maize stover
Ration Mean SE Mean SE
A 32.8 1.29 328 1.29
B 39.2 1.29 36.2 0.29
C 41.4 0.67 35.7 0.83
D 42.8 1.29 33.8 1.29
Ration A = unsupplemented
Ration B = supplemented with 3 g Leucaena DM/kg liveweight per day
Ration C = supplemented with 6 g Leucaena DM/kg liveweight per day
Ration D = supplemented with 9 g Leucaena DM/kg liveweight per day
and OM degradabilities at 48 hours of incubation revealed that ration A had
significantly (P<0.05) lower DM and OM degradability than the supplemented
rations. Ration B had lower (P<0.05) DM and OM degradabilities than ration D,
but the differences between rations B and C or rations C and D were not
significant (P>0.05).
Table 2. Dry-matter and organic-matter degradabdities ofmaize stover at different incubation
times
Degradability (%) at various incubation times
48 hours
Ration 0 hours 6 hours 12 hours 24 hours Mean SE 72 hours
Dry-matter degradability
A 7.25 7.73 9.65 12.99 14.84 0.01 29.94
B 7.25 11.05 15.95 23.68 33.79 1.46 44.44
C 7.25 13.38 19.11 28.62 35.02 0.48 52.59
D 7.25 8.13 16.63 27.20 37.60 0.30 51.59
Organic-matter degradability
A 3.96 4.42 6.40 10.65 12.12 0.89 29.38
B 3.96 7.48 12.59 20.75 31.74 1.26 41.60
C 3.96 9.90 15.73 25.55 32.71 0.37 51.19
D 3.96 6.61 13.10 24.15 35.76 0.40 49.58
Ration A = unsupplemented
Ration B = supplemented with 3 g Leucaena DM/kg liveweight per day
Ration C = supplemented with 6 g Leucaena DM/kg liveweight per day
Ration D = supplemented with 9 g Leucaena DM/kg liveweight per day
167
Rumen ammonia concentrations in sheep fed the four rations are shown in
Table 3. Inclusion olLeucaena in the maize-stover-based diet significantly
(P<0.05) increased the rumen ammonia concentration. The concentration in
sheep fed ration B was significantly (P<0.05) lower than those in sheep fed
rations C and D, which were not different (P>0.05) from each other.
Rumen ammonia concentration increased immediately after feeding, and
then decreased (Figure 1).
Rumen pH was not affected (P>0.05) by ration (Table 3).
DISCUSSION
The high dry-matter intake of rations supplemented with Leucaena indicates that
Leucaena is a good supplement to low quality roughages such as maize stover.
This improvement in intake with Leucaena supplementation is in agreement with
results reported by Bamualim et al (1984). However, Dixon et al (1981)
cautioned that an increase in total dry-matter intake could be due to consumption
of the supplement per se rather than the roughage.
The fact that the highest dry-matter intake of maize stover was obtained at a
supplementation level of 3 g Leucaena DM/kg liveweight per day may indicate
that it is this optimum level of supplementation for poor quality roughages.
Further increase in the level ofLeucaena supplementation led to a substitution
effect whereby the intake of maize stover was reduced. Increase in the intake of
maize stover with Leucaena supplementation could be due to the increase in the
concentration of rumen ammonia and dry-matter degradability of maize stover.
The improvement in the rumen degradation of maize stover dry matter and
organic matter with Leucaena supplementation indicates a possible improvement
in microbial growth. This is supported by the observed increase in rumen
ammonia concentration.
Table 3. Rumen ammonia concentration and rumenpHfor the four rations
Rumen ammonia concentration
(mg/litre) Rumen pH
Ration Mean SE Mean SE
A 32.0 4.83 6.83 0.07
B 74.8 6.21 7.10 0.65
C 91.3 6.71 6.61 0.03
D 90.1 6.16 6.9 0.07
Ration A = unsupplemented
Ration B = supplemented with 3 g Leucaena DM/kg liveweight per day
Ration C = supplemented with 6 g Leucaena DM/kg liveweight per day
Ration D = supplemented with 9 g Leucaena DM/kg liveweight per day
168
Figure 1. Rumen ammonia concentration before and after feeding the four rations
Rumen ammonia
concentration (mg/litre)
140 -.
O Ration A = unsupplemented
• Ration B = supplemented with 3 g Leucaena DM/kg liveweight per day
A Ration C = supplemented with 6 g Leucaena DM/kg liveweight per day
. . □ Ration D = supplemented with 9 g Leucaena DM/kg liveweight per day
120
 
4 6 8 10
Hours after feeding
169
Rumen ammonia concentration is an indicator of nitrogen available for
microbial protein synthesis. In this study, rumen ammonia concentration
increased from 32 mg/litre for the unsupplemented diet to about 90 mg/litre for
higher levels o£ Leucaena supplementation. FAO (1986) reported that, for
efficient rumen function, ammonia concentration in the rumen should be
between 50 and 90 mg/litre. With the unsupplemented maize stover diet, the
rumen ammonia concentration was below the critical level, and this corresponds
with the low dry-matter intake and dry-matter and organic-matter degradabilities
for that ration.
CONCLUSIONS AND RECOMMENDATIONS
Dry-matter intake, rumen degradation and rumen ammonia concentration all
showed improvement when the maize stover diet was supplemented with
Leucaena leucocephala. This means that the efficiency of utilisation of maize
stover is improved by Leucaena inclusion. However, the improvement declined
at higher levels oiLeucaena supplementation. It is therefore recommended to
supplement maize stover with Leucaena at a level not exceeding 6 g DM/kg
liveweight per day.
REFERENCES
Bamualim A Weston R H, Hogan J P and Murray R M. 1984. The contributions of
Leucaena leucocephala to post ruminal digestible protein for sheep fed tropical
pasture hay supplemented with urea and minerals. Animal Production in Australia
15:255-258.
Dixon R M, Priego A Wyllie D and Preston T R. 1981. Intake, rumen liquid flow rates
and fermentation in bulls fed sisal pulp supplemented with Leucaena forage, pasture
or rice polishings. TropicalAnimal Production 6:37-43.
El-Naga M A. 1989. Improving the intake and utilization of by-product-based diets. In:
Said A N and Dzowela B H (eds), Overcoming constraints to the efficient utilization of
agricultural by-products as animalfeed. Proceedings of the Fourth Annual Workshop
held at the Institute of Animal Research, Mankon Station, Bamenda, Cameroun,
20-27 October 1987. ARNAB (African Research Network for Agricultural
By-products). ILCA(International Livestock Centre for Africa), Addis Ababa
Ethiopia. pp. 354—362.
FAO (Food and Agriculture Organization of the United Nations). 1986. Better utilization
ofcrop residues and by-products in animalfeeding: Research guidelines. 2. A
practical manualfor research workers. FAO Animal Production and Health Paper
50/2. FAO, Rome, Italy. 154 pp.
Kategile J A. 1979. Performance of heifers fed on diets based on NaOH treated maize
cobs and the effect of supplementary urea and source of carbohydrates. Animal Feed
Science and Technology 4:97-107.
170
Kiangi EMI. 1981. Ammonia treatment of low quality roughages to improve their
nutritive value. In: Kategile J A Said A N and Sundstol F (eds), Proceedings ofa
workshop on the utilization of low quality roughages in Africa, held atArusha,
Tanzania, 18-22 January 1981. AUN Agricultural Development Report 1. AUN
(Agricultural University of Norway), Aas. Norway. pp. 49-54
0rskov E R, Hovell F D DeB and Mould F. 1980. The use of the nylon bag technique for
the evaluation of feedstuffs. TropicalAnimal Production 5:195-213.
Raymond F M. 1989. Effect of urea treatment on intake of bean straw (Belabela var) by
goats. Special project. Sokoine University of Agriculture, Morogoro, Tanzania.
Snedecor G W and Cochran W G. 1980. Statistical methods. 7th edition. Iowa State
University Press, Ames, Iowa, USA. 507 pp.
Urio N A 1977. Improvement of low quality roughages by alkali treatment under
Tanzanian conditions. MSc Thesis. University of Dar es Salaam, Tanzania.
171
172
BROWSE SPECIES AND SUPPLEMENTS USED FOR FEEDING
SMALLRUMINANTS IN OGUN STATE, NIGERIA
CFIOnwuka1, BBA Taiwo2 andlFAdu1
College of Animal Science and Livestock Production
University of Agriculture
PMB 2240, Abeokuta, Ogun State, Nigeria
2 Department of Animal Production
Ogun State University
Ago-Iwoye, Ogun State, Nigeria
ABSTRACT
A questionnaire survey was conducted to determine the browse species and
supplementary feeds used for sheep and goat production in Ogun State,
south-west Nigeria. Results indicate that farmers sustain their sheep and goats on
browse plants supplemented by farm and household wastes. The predominant
browses are Spondias mombin, Gliricidia sepium, Ficus sp and Marantochloa
leucantha; the main supplements are cassava, cocoyam and yam peels, maize
residues and millet; and grasses include Panicum maximum and Cynodon sp. The
supplements fill the animal feed availability gap during dry months. Farmers
spend variable amounts on supplements and little effort is made to establish
pastures. Alley farming and intensive feed gardens are not common in this area.
Free ranging and cut-and-carry systems are predominantly practised.
RESUME
Les ligneuxfourragers et les aliments complementaires dans ialimentation
despetits ruminants dans I'Etat d'Ogun (Nigeria)
Une etude a eté effectuée a partir d'un questionnaire en vue de determiner les
espices ligneuses fourragères et les complements alimentaires utilises dans
I'élevage des ovins et des caprins dans I'Etat d'Ogun, dans le sud-ouest du
Nigeria. II ressort des resultats enregistres que lespaysans nourrissaient leurs
animaux avec des ligneux, des sous-produits agricoles et des ordures menagères.
Les espèces ligneuses les plus utilisees etaient Spondias mombin, Gliricidia
sepium, Ficus sp et Marantochloa leucantha; les principaux sous-produits
173
agricoles etaient les pelures de manioc, de taro et d'igname ainsi que les residus
des cultures de mats et de mil. Certaines graminees entraient en outre dans
I'alimentation de ces animaux, notamment Panicum maximum et Cynodon sp.
Utilises pour combler les deficits de saison sèche, les aliments complementaires
occasionnaient des depenses variables. Les pâturages artificiels, les cultures en
couloirs et les vergers d'embouche etaient rares dans cette région. En revanche,
la divagation et I'alimentation a I'auge etaient extrimement frequentes.
INTRODUCTION
Browse forms an important part of goat diets in the tropics (Devendra and Burns,
1983), especially in rural areas where goat meat is a major source of protein.
Livestock feeds and feeding have always been production constraints in
sub-Saharan Africa; inadequate feeding can lead to reproductive wastage, low
birth weights, high infant mortality, etc (Sumberg, 1985: Reynolds, 1986).
Rural small ruminants roam around freely and eat a variety of grasses,
legumes and kitchen wastes. However, during the dry season, green forages are
less nutritive, particularly grasses which are ligniQed (le Houcrou, 1983). The
feed problem is further magnified by the handling of small-ruminant production
as a minor enterprise with few or no inputs. With the pressure on land for crop
production, there is need now, more than ever before, to look in depth into the
feeds and feeding of small ruminants.
The nutritive values of browse plants to livestock have been studied (Jones,
1979; Onwuka, et al, 1989). This study was concerned mainly with identifying
browse species and supplements fed to sheep and goats in south-west Nigeria.
MATERIALS AND METHODS
Three hundred questionnaires were administered by trained enumerators to
small-ruminant owners in five Local Government Areas (Remo, Obafemi-
Owode, Egbado North, Ifo and Ijebu-Ode) of Ogun State, south-west Nigeria,
during the wet and dry seasons of 1990. The five areas were randomly selected
to represent the socio-political and ecological zones of the state.
The questionnaires covered such topics as the types of feeds used, sources,
times of feeding, reasons for using specific forages, the commonest browses and
supplements in use, and awareness by the farmers of intensive feed garden/alley
farming technology. To minimise errors, the same trained enumerators were used
in all five Local Government Areas. They could all communicate in the local
language of these areas.
In most cases the interviewee was the household head. Some of the forages
used by the respondents to feed their stock were collected for identification.
174
RESULTS AND DISCUSSION
A total of 290 questionnaires were recovered.
Small-ruminant owners in the study area show a clear preference for goats;
74% of the households surveyed owned goats (average flock size 5.1), but only
13% owned sheep (average flock size 1.9).
Most of the respondents were crop farmers and traders (Table 1) who use
family labour to take care (if any) of their livestock. There are no large
commercial goat and sheep enterprises in the areas surveyed.
Table 1. Predominant occupations ofsurvey respondents in five Local GovernmentAreas in Ogun
State, Nigeria, 1990
Percentage of respondents by occupation
Obafemi-
Owode
Egbado
NorthOccupation Remo Ifo Ijebu-Ode
Fanning 50.0 95.2 76.7 70.4 920
Trading 31.0 4.8 14.0 16.6 1.6
Civil servants 3.4 - 4.7 7.0 4.8
Retired civil servants 5.2 - 2.3 2.8 -
Tradesmen 3.4 - 2.3 3.2 1.6
Unemployed 1.7 - - - -
Others 5.3 - - - -
Small ruminants are generally left to roam freely and fend for themselves
on whatever forage or other feed they can find. However, household wastes
(cassava, yam and cocoyam peels) are given to stock as supplements (Table 2);
they are offered in the mornings, or as they become available. Cut forages are
de-emphasised during the dry season when green material is in short supply.
Table 3 shows the commonest browse species and supplements used in
small-ruminant production in the study area. Some of these browses and
supplements have high nutritive value and can support animal production
(Oyenuga, 1978; Fomunyam and Meffeja, 1987; Onwuka et al, 1989). Their use
could, however, be limited by some antinutritional components (Onwuka, 1991).
The supplements come mainly from the stock owners' farms. Farmers also
buy some supplements (Table 4) from either local markets or neighbours, but
generally small-ruminant owners invest minimally in animal feed (Table 5).
None of the respondents in this study claimed that they used compounded diets.
Most sheep and goat keepers give specific forages to their stock believing
that they induce rapid growth rates; some use them for medicinal purposes and a
few use some forages to prevent their animals being attacked by evil spirits
(Table 6). Table 7 shows that browse are generally fed to ruminants because they
are readily available and palatable.
175
Table 2. Sources ofanimalfeeds by season in five Local Government Areas in Ogun State,
Nigeria, 1990
Sources of feed (%) by season
Remo
Obafemi-
Owode
Egbado
North Ifo Ijebu-Ode
Dry Wet Dry Wet Dry Wet Dry Wet Dry Wet
Animals fending
for self
37.7 39.5 51.6 8.1 25.9 34.5 25.0 50.0 50.8 50.4
Improved pasture 17.8 13.2 1.6 1.6 25.9 29.3
Household waste 35.6 40.7 45.2 38.7 34.5 25.9 75.0
Cut forages 8.9 6.6 1.6 51.6 13.7 10.3
45.8 38.2
50.0 3.4 11.4
Table 3. Commonest browsesIgrasses and supplements in use in five Local GovernmentAreas in
Ogun State, Nigeria, 1990
Obafemi-
Owode
% of total diet
Egbado
NorthFeed Remo Ifo Ijebu-Ode
Browse/grass
Grass/pasture 14.6 29.9 5.9 15.0 36.4
Musa cv paradisciaca 1.2 - - 1.0 -
Cymbopogon cutrilis 3.7 - - - -
GliricuHa sepium - - 3.5 - 1.1
Marantochloa leucantha - 2.0 - - -
Spondias mombin - - 1.2 20 -
Ficus sp - - 2.0 3.0 -
"Ewe akoko" - - 1.2 2O -
Leucaena leucocephala - - 1.2 - -
Supplements
Cassava peels 58.5 53.7 34.5 40.0 34.1
Yam peels 4.9 7.2 9.4 5.0 -
Cocoyam peels 1.2 7.2 - 7.0 12.5
Millet - - 15.3 - -
Maize waste 15.9 - 25.8 25.0 15.9
The forages usually preferred by stockmen are Eupatorium odoratum, giant
star grass, elephant grass, lemon grass, cassava leaves, Guinea grass, bamboo
leaves, Ficus sp, Centrosema pubescens, Spondias mombin, Aegeratum
conizoides, Cida acuta, Talinum triangulaire.
176
Table 4. Types offeedstuffs bought by sheep and goats farmers in five Local Government Areas
in Ogun State, Nigeria, 1990
% of purchased feeds
Obafemi-
Feedstuff Remo Owode Egbado North Ifo Ijebu-Ode
Cassava peels 59.2 64.6 37.5 55.4 11.8
Maize chaff 13.6 26.2 25.0 20.5 35.5
Yam peels - - 6.3 6.0 -
Millet - 1.5 18.7 8.6 -
Dried brewers' grain - - 3.1 - 2.7
Cocoyam peels - 4.6 - 9.5 14.7
Rice waste - - - - 35.3
Lemon grass 13.6 3.1 - - -
Cassava leaves 13.6 - 9.4 - -
Table 5. Attitudes ofsheep aidgoat keepers to the purchase offeeds in five Local Government
Areas in Ogun State, Nigeria, 1990
Percentage of respondents
Remo
Obafemi -
Owode
Egbado
North Ifo Ijebu-Ode
Fanners that buy feed
Farmers that do not buy feed
Fanners indifferent to purchase
of feed
31.0
653
3.5
33.9
59.7
6.4
27.9
65.1
7.0
36.3
57.6
6.1
30.2
68.2
1.6
Table 6. Reasonsfor use ofspecific forages in five Local GovernmentAreas in Ogun State,
Nigeria, 1990
Percentage of farmers giving reason
Obafemi -
Owode
Egbado
NorthReason Remo Ifo Ijebu-Ode
Rapid growth of animals 88.9 81.3 68.9 83.4 95.0
Medicinal 11.1 IIS 28.9 10.0 5.0
Fetish beliefs - 6.2 2.2 6.o -
Although stock owners are willing to feed forage to their stock, they are not
willing to propagate the crops to ensure availability (except in Ijebu-Ode; Table
8). The major constraints are availability of land and capital (Table 9). The land
177
Table 7. Reasons forfeeding forage to sheep and goats in five Local GovernmentAreas in Ogun
State, Nigeria, 1990
Percentage of farmers giving reason
Obafemi-
Owode
Egbado
NorthReason Remo Ifo Ijebu-Ode
Readily available 51.8 - 40.7 50.0 31.2
Palatable 13.8 1.6 50.0 50.0 -
The only species fanners know 10.3 62.9 1.9 - 6.3
Cheap 13.8 12.9 5.5 - 62.5
Recommended by others 10.3 - 1.9 - -
Table 8. Attitude offarmers to growing forage in five Local GovernmentAreas in Ogun State,
Nigeria, 1990
Obafemi-
Owode
Percentage of respondents
Egbado
NorthRemo Ifo Ijebu-Ode
Willing to plant
Not willint to plant
Undecided
34.5 17.7
45.2
37.1
35.7
40.5
23.8
34.8 71.4
51.7
13.8
60.0 27.0
5.2 1.6
Table 9. Majorproblems associated with fodderproduction in five Local GovernmentAreas in
Ogun State, Nigeria, 1990
Percentage of farmers citing problems
Obafemi-
Owode
Egbado
NorthProblem Remo Ifo Ijebu-Ode
Land 64.0 353 25.6 28.4 20.6
Credit 10.3 47.1 41.9 30.4 66.7
Labour 10.3 - 18.6 - -
Seed availability 5.1 17.6 4.6 38.0 11.1
Others 10.3 - 9.3 3.2 1.6
issue is worsened by the land-use policy in the country. These are usually
subsistence farmers who invest minimally in their enterprises and will not
welcome any extra investment in feed/forage propagation, except, of course, for
crops that can also be used as food.
178
The survey found few farmers who were aware of alley farming or intensive
feed gardens (Table 10). However, many farmers indicated an interest in these
technologies when the possibilities of augmenting animal feed supply were
explained to them (Table 11). The interest in alley farming may be partly
explained by the perceived human food benefits of this technology.
Table 10. Awareness of intensive feed garden and alley farming technologies by sheep and goat
farmers in five Local Government Areas in Ogun State, Nigeria, 1990
Percentage of respondents
Obafemi-
Remo Owode
Egbado
North Ifo Ijebu-Ode
Unaware
Aware
98.3 100 86.1 90.0
13.9 10.0
81.7
18.31.7
Table 11. Willingness to establish alley farms/intensive feed gardens in five Local Government
Areas in Ogun State, Nigeria, 1990
Percentage of respondents
Obafemi-
Remo Owode
Egbado
North Ifo Ijebu-Ode
Willing to establish intensive
feed gardens
Willing to establish alley farms
Undecided
50.0
13.8
36.2
6.5
93.5
40
22.2
37.8
40
29.1
30.9
27.0
65.1
7.9
When they were shown a detailed analysis of the benefits of investing in
livestock feed, up to 85% of the small-ruminant farmers interviewed were
willing to invest up to Naira 500 (about US$ 63) a year to purchase feed
supplements. Some, however, were ready to stake up to US$ 380, provided they
could be guaranteed a return from such investments. Granted that nutrition is just
one of the small-ruminant production constraints in sub-Saharan Africa, with a
good nutritional base, other factors could be kept to the barest minimum.
CONCLUSION
Browse plants supplemented with some agricultural byproducts form an essential
component of goat and sheep diets in Ogun State, south-west Nigeria.
Small-ruminants owners invest minimally in livestock production and so have to
resort to cheap green feeds and supplements while allowing the animals to fend
for themselves. Browses are fed to small ruminants when they are readily
available and because farmers believe browses initiate rapid weight gains in their
179
animals. However, most small-ruminant owners do not cultivate forage because
land and planting materials are scarce, and they are reluctant to invest in
non-food-crop production. A lot of extension work still needs to be done to
interest rural farmers in forage-producing technologies; such technologies could
provide important feed resources, especially during the dry period when
available grasses are low in feed quality.
ACKNOWLEDGEMENTS
The National Livestock Projects Department is gratefully acknowledged for
support of this research.
REFERENCES
Devendra C and Burns M. 1983. Goat production in the tropics. Commonwealth
Agricultural Bureaux, Wallingford, UK. 184 pp.
Fomunyam R T and Meffeja F. 1987. Cassava by-products in rabbit and sheep diets. In:
Little D Aand Said AN (eds), Utilization of agricultural by-products as livestock
feeds in Africa. Proceedings of a workshop held at Ryall's Hotel, Blantyre, Malawi,
September 1986. ARNAB (African Research Network for Agricultural By-products).
ILCA (International Livestock Centre for Africa), Addis Ababa, Ethiopia. pp. 103-107.
le Houerou H N. 1983. Chemical composition and nutritive value of browse in tropical
West Africa. In: le Houerou H N (ed), Browse in Africa: The current state of
knowledge. ILCA (International Livestock Centre for Africa), Addis Ababa, Ethiopia.
pp. 261-289.
Jones R J. 1979. The value of Leucaena leucocephala as feed for ruminants in the tropics.
WorldAnimal Review 31:13-23.
Onwuka C F I. 1991. Tannin and saponin contents of some tropical browse species fed to
goats. Tropical Agriculture (Trinidad) (In press).
Onwuka C F I, Akinsoyinu A O and Tewe O 0. 1989. Feed value of some Nigerian
browse plants: Chemical composition and "in vitro" digestibility. EastAfrican
Agricultural and Forestry Journal 54:3.
Oyenuga V A. 1978. Nigeria's foods andfeeding-stuffs. 3rd edition. Ibadan University
Press, Ibadan, Nigeria. 99 pp.
Reynolds L. 1986. Small ruminant production: The present situation and possible
nutritional interventions for improvement. ILCA Bulletin 25:13-16. iLCA
(International Livestock Centre for Africa), Addis Ababa, Ethiopia
Sumberg J E. 1985. Small ruminant feed production in a farming systems context. In:
Sumberg J E and Cassaday K (eds), Sheep and goats in humid West Africa.
Proceedings of the workshop on small ruminant production systems in the humid zone
of West Africa, held in Ibadan, Nigeria, 23-26 January 1984. ILCA (International
Livestock Centre for Africa), Addis Ababa, Ethiopia. pp. 41-46.
180
BODY WEIGHTRESPONSE OF WESTAFRICAN DWARF
GOATS FED GURICIDIA SEPIUM, PANICUMMAXIMUMAND
CASSAVA (MANIHOT) PEELS
OJIfut
Department of Animal Science
University of Cross River State, Okuku Campus
PMB 1219 Ogoja, Cross River State, Nigeria
ABSTRACT
Six diets, 100% Gliricidia sepium (Tl), 100% Panicum maximum (T2), 100%
cassava peels (T3), 35% G. sepium plus 35% P. maximum plus 30% cassava
peels (T4), 70% G. sepium plus 30% cassava peels (T5) and 70% P. maximum
plus 30% cassava peels (T6) were fed to 24 intact male West African Dwarf
goats in a completely randomised experiment. Four bucks were randomly
assigned to each dietary treatment for 90 days. Treatment T3 was discontinued
after 28 days and results for this treatment are not presented.
Goats on T4 consumed the most dry matter (DM) and organic matter (OM)
(P<0.05); those on Tl consumed most acid detergent fibre (ADF) and neutral
detergent fibre (NDF); and those on Tl consumed the highest amount of nitrogen
(N). Least N consumption was by goats on T2 and T6. Goats on Tl digested DM
and OM least (P<0.05); those on T2 digested ADF most (P<0.05); N and NDF
were best digested (P<0.05) by goats on T5. Goats on diet T4 achieved the
highest liveweight gains (P<0.05).
Supplementing equal proportions of G. sepium and P. maximum with 30%
(w/w) cassava peels appeared most beneficial to goats.
RESUME
Performances pondérales de chevres naines d'Afrique occidentale soumises a
des rations composées de Gliricidia sepium, de Panicum maximum et de
pelures de manioc (Manihoty
Six rations constitutes de 100% de Gliricidia sepium (Ti); 100% de Panicum
maximum (T2); 100% de pelures de manioc (T3); 35% de G. sepiumplus 35%
de P. maximum plus 30% de pelures de manioc (T4); 70% de G. sepium plus
30% de pelures de manioc (T5); et 70% de P. maximumplus 30% de pelures de
181
manioc <J6) ont ete servies chacune pendant 90jours a quatre boucs entiers de
la race naine d'Afrique occidentale. Cette experience a ete concue sur le modele
des blocs aleatoires complets et les animaux ont ete assignes au hasard a I'un ou
I'autre de ces traitements. Les résultats enregistres pour le traitement T3 n'ont
pas ete presented car celui-ci avail ete interrompu au bout de 28jours d'essai
La consommation de matiere seche (MS) et de matiere organique etait
maximumpour la ration T4. Celle de lignocellulose et de fibres NDF etait laplus
élevee pour la ration T2, tandis que celle d' azote etait maximum pour la ration
Ti. Quant au niveau minimum de consommation d'azote, il avait éti enregistré
pour les rations T2 et T6- Le taux de digestibilite de la matiere seche et celui de
la matiere organique etaient minimums (P<0,05) pour la ration Ti; celui de la
lignocellulose etait maximum (P<0,05) pour la ration T2 tandis que ceux de
I'azote et de la fibreNDF étaient maximum pour la ration T5 (P<0,05). Enfin,
les gains depoids les plus éleves etaient associes a la ration T4 (P<0,05).
La combinaison alliant G. sepium et P. maximum en proportions egales
avec enpoids 30% depelures de manioc semble étre la phis indiquéepour les
caprins.
INTRODUCTION
West African Dwarf goats are among the few important irypanotolerant livestock
species of humid Nigeria. Matthewman (1979) reported an average of four goats
per household in humid Nigeria but larger numbers are kept in the savannah
parts of the country. Nigeria has an estimated 26 million goats.
Inadequate nutrition has been recognised as the major constraint to
livestock, especially goat, production in Nigeria (Olubajo and Oyenuga, 1974).
The use olGliricidia sepium as livestock feed has received attention in
Nigeria only recently (Mba et al, 1982; Onwuka, 1983; Ademosun et al, 1985).
The chemical composition of G. sepium has been variously reported as
7.4-34.5% dry matter (DM) ("as-fed basis"), 81.9-92.3% organic matter (OM),
3.1-4.2% nitrogen (N), 30.8% neutral detergent fibre (NDF), 18.5-44.4% acid
detergent fibre (ADF) and 12.7-32.5% crude fibre (CF) (Chadhokar, 1982; Ifut,
1987).
Panicum maximum is highly palatable to ruminant animals and has
23.5-29.9% DM at harvest (Olubajo, 1977; Aken' ova and Mohamed-Saleem
1982; Ifut, 1987). Nitrogen content in Panicum maximum ranges from 0.8 to
2.0% DM and CF from 29.5 to 42.2% DM (Akinyemi and Onayinka 1982; Ifut,
1987).
In parts of Nigeria where Manihot (cassava) is grown, the average annual
yield of tubers is 21.1 t/ha. Since peels constitute about 20% of the tuber, large
quantities of cassava peels could be available to feed ruminants, especially goats.
Currently, however, cassava peels are largely under-exploited as livestock feed.
Cassava peels have been found to contain 86.5-94.5% DM 89.0-93.9%
OM 10.0-31.8% CF and 0.7-1.0% N (Oyenuga, 1968; Adegbola, 1980; Carew,
182
1982; Onwuka, 1983; Ifut, 1987). Sun-dried cassava peels have been reported to
contain 14.2-116.9 mg HCN/kg, depending on variety. Sun-drying has been
reported to reduce HCN content by 89.4-94.0% rendering the peels innocuous
(Maner and Gomez, 1973; Tewe et al, 1976).
Average G. septum DM intake of goats has been reported as 66.7 g/kg '
per day (Ademosun et al, 1988) and 21.3 g/kg0'75 per day (Carew, 1983;
Onwuka, 1983; Ademosun et al 1985). Mba et al (1982) also noted DM intake
values of G. septum by kids ranging from 54.8 to 71.3 g/kg0'75 per day.
Growing West African Dwarf goats fed Panicum achieved daily DM intakes
ranging from 54.9 g/kg ' for young, well fertilised grass to 43.1 g/kg0' for
standing hay (Ademosun et al, 1988).
Reported liveweight gains by growing West African Dwarf goats on a sole
Gliricidia diet were 173-20.0 g/day (Onwuka, 1983) 27.0 g/day (Mba et al,
1982) and 233 g/day (Ademosun et al, 1988).
This paper reports work on intake and body weight response by goats fed
Gliricidia and cassava peels, Panicum and cassava peels and Gliricidia plus
Panicum plus cassava peels.
MATERIALS AND METHODS
Twenty-four growing, parasite-free, intact West African Dwarf bucks aged six to
nine months and weighing an average of 6 kg (range 5-10 kg), obtained from the
University of Ibadan Teaching and Research Farm, were used for this
experiment. The bucks were housed for 90 days in previously sanitised
individual metabolism cages and offered liberal, but known, quantities of the
experimental diets daily for a 21-day preliminary period to adapt the animals to
the diets and cage environment. Fresh water and salt lick were available ad
libitum in the cages.
Fresh G. sepium branches (about 1.2 m long and 1.5 cm thick) with leaves
and branchlets and fresh P. maximum, chopped to about 2 cm length, were
obtained daily from ILCA Ibadan, during the wet season (April-July). Cassava
peels from low-HCN TMS 30572 and TMS 1425 varieties were obtained fresh
from local cassava grating plants in and around the University of Ibadan campus.
The peels were sun-dried for three to four days.
Diets fed to the goats were:
100% G. sepium (Tl)
100% P. maximum (T2)
100% dried cassava peels (T3)
35% (w/w) each of G. sepium and P. maximum plus 30% cassava peels (T4)
70% G. sepium plus 30% cassava peels (T5)
70% P. maximum plus 30% cassava peels (T6).
Treatment T3 was discontinued after 28 days because the animals were
losing weight and were in danger of dying.
183
The amount of each diet offered to each experimental animal ensured at
least a 5% left-over. Residues were collected after a 24-hour feeding, weighed
and the voluntary intake determined.
Samples of the diets offered and rejected were taken daily during the 90-day
period. Subsamples of each were taken for DM and chemical determination
according to standard methods (AOAC, 1975; Van Soest and Robertson, 1980).
Total faeces and total urine were collected in the mornings before feeding
and watering during days 22-28 and 84-90 of the experiment. The faeces were
weighed fresh and 10% aliquots of each day's collection for each animal were
taken, dried at 60°C for 48 hours in a forced draught air oven and bulked. A
subsample of faeces from each animal was dried in a similar oven at 100-105°C
for 48 hours for DM determination. The two seven-day faecal samples for each
experimental animal were thoroughly mixed and milled to pass through a
0.6-mm sieve and put in sealed polythene bags until analysed.
The urine was collected in a plastic bucket placed under each cage; 75 ml of
25% sulphuric acid was added to the bucket daily to curtail volatilisation of
ammonia from the urine. The total output of urine per animal was measured and
10% aliquots were saved in stoppered, numbered plastic bottles and stored at
-5°C. At the end of each seven-day collection period the sample collections were
bulked for each animal and subsamples were taken for analysis.
The animals were weighed once a week in the morning before feeding and
watering. Liveweight change was estimated as the difference between the initial
and final body weights of the animals during the experiment.
The data obtained were subjected to analysis of variance and correlation
analyses. Differences between treatment means were determined by Duncan's
multiple range test using the Genstat V computer program, release 4.04B (1984,
Lawes Agricultural Trust, Rothamsted Experimental Station, UK).
RESULTS AND DISCUSSION
No results are presented for treatment T3. This treatment was discontinued after
only 28 days, because the animals were losing weight dramatically. HCN
toxicity could not have been implicated in this liveweight loss because sun-dried,
low-HCN varieties of cassava were used, but it is clear that a diet of sole cassava
peels is not a suitable feed for goats.
The chemical compositions of the other five experimental diets are shown
in Table 1. Chemical components of G. septum, P. maximum and cassava peels
compare favourably with values reported in literature (Oyenuga, 1968; Olubajo,
1977; Adegbola, 1980; Aken'ova and Mohamed-Saleem, 1982; Carew, 1983;
Chadhokar and Sivasupiramaniam, 1983; Onwuka, 1983; Ifut, 1987).
Dry-matter and nutrient intakes and digestibilities by West African Dwarf
goats are summarised in Table 2.
The highest DM and OM intakes were from diet T4 probably because this
combination was more palatable than the other diets.
184
Table 1. Chemical composition ofthe diets fed to WestAfrican Dwarfgoats (means ofsix
determinations)
DM (%) %ofDM
Diet As fed Residual OM ADF NDF N
Tl 31.0 87.3 91.3 28.3 41.5 3.8
T2 24.7 88.9 87.7 40.2 65.5 1.7
T4 45.4 87.9 89.4 31.1 47.7 2.2
T5 47.7 87.3 90.7 27.0 39.3 2.9
T6 43.2 88.4 88.1 35.3 56.1 1.5
Diet Tl = 100% Gliricidia septum
Diet T2 = 100% Panicum maximum
Diet T4= 35% G. sepium + 35% P. maximum + 30% cassava peels
Diet T5= 70% G. sepium + 30% cassava peels
Diet T6= 70% P. maximum + 30% cassava peels
Table 2. Dry-matter and nutrient intakes, digestibility coefficients and body weight changes of
West African Dwarfgoats
Parameter Diet Tl DietT2 DietT4 DietT5 DietT6 SE
Intake (g/kg*'75 per day)
Dry matter (DM) 46.3 63.5 86.4 76.0 73.8 8.7
Organic matter (OM) 43.0 55.1 77.3 67.5 64.6 7.8
Acid detergent fibre (ADF) 18.7 27.5 20.8 20.5 26.9 3.9
Neutral detergent fibre (NDF) 27.7 44.4 36.2 36.9 41.1 5.6
Nitrogen (N) 1.8 1.1 1.5 1.5 1.1 0.3
Digestibility coefficients (%)
DM 54.2 58.8 71.9 74.3 65.2 4.1
OM 56.8 61.1 73.1 76.6 67.5 4.0
ADF 42.9 60.1 36.1 46.2 58.4 3.6
NDF 48.2 54.5 57.4 67.7 62.6 4.7
N 56.5 27.1 41.0 57.3 56.7 7.2
Body weight change (g/day) 51.0 25.7 66.3 54.2 41.5 0.3
Diet Tl = 100% Gliricidia sepium
Diet T2 = 100% Panicum maximum
Diet T4 = 35% G. sepium + 35% P. maximum + 30% cassava peels
Diet T5 = 70% G. sepium + 30% cassava peels
Diet T6 = 70% P. maximum + 30% cassava peels
185
The highest intake of NDF and ADF was by goats on T2. ADF intake from
T6 was significantly (P<0.05) the highest among the composite diets. However,
there were no differences (P>0.05) in NDF intake among the composite diets.
Dry matter of T5 was digested best by goats, probably due to a better
balance of nutrients resulting from the simultaneous feeding of N-rich Gliricidia
(70%) and soluble carbohydrate-rich (30%) peels. DM digestibility of T6 was
superior (P<0.05) to that of T2.
The N of T5 was digested most, which suggests that a favourable energy:N
balance resulted from the diet. However, the N digestibility of T5 was not
different (P>0.05) from that Tl or T6.
Supplementating either Gliricidia or Panicum with 30% cassava peels did
not seem to improve (P>0.05) ADF digestibility. However, the composite diets
contained NDF which was distinctly superior (P<0.05) in digestibility to that
contained in Tl. The highest NDFD of T5 might have been due to a better
balance of nutrients, particularly N from Gliricidia and soluble carbohydrates
from the peels.
The highest average daily body weight gain was by goats on T4, probably
because this diet provided the best balance of nutrients for growth. Goats gained
more weight when Gliricidia or Panicum was supplemented with 30% cassava
peels than when each was fed alone.
CONCLUSION
Cassava peel, as a supplement to a leguminous and/or grass feed, is potentially
beneficial to goats as a source of readily available carbohydrates. The most
beneficial diet appeared to be equal proportions of G. sepium and P. maximum
supplemented with 30% (w/w) cassava peels.
ACKNOWLEDGEMENT
I am grateful to the University of Ibadan, ILCA Humid Zone Programme,
Ibadan, and the International Institute of Tropical Agriculture (IITA), Ibadan,
Nigeria, for making available the materials and facilities for this research.
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188
THE FEEDING VALUE OF CROP RESIDUES FROM SORGHUM,
PEARLAND FINGERMILLET CULTIVARS
S Ncube and TSmith
Matopos Research Station
Private Bag K 5137, Bulawayo, Zimbabwe
ABSTRACT
Two experiments were conducted to evaluate the value of sorghum and millet
residues as feeds for indigenous sheep. In the first, wethers received a daily diet
of 100 g cottonseed meal plus hay (control) or one of the following stovers ad
libitum: sorghum (white, SVI; or red, DC75); pearl millet (white, SDMV 89004;
or red NCD2); finger millet (white, SDFM 63; or red, 25C). Nitrogen (N) and
neutral detergent fibre (NDF) concentrations differed between species but not
variety. Finger millet stover contained most N and least NDF, was most readily
eaten (P<0.05) and resulted in the highest N retention and the lowest NDF
digestibility. In the second experiment wethers received one of the following
diets: hay plus 100 g/day cottonseed meal (control); threshed heads of white
(SVI) or red (DC75) sorghum, with or without 100 g/day cottonseed meal; or
threshed heads of red finger millet (25C). Finger millet heads contained most N
and least NDF and were most readily eaten and digested (P<0.05). The addition
of cottonseed meal was beneficial and SVI was more digested than DC75.
RESUME
Valeur nutritive de residus de cultivars de sorgho, de milperle et d'éleusine
Deux experiences ont ete effectuees en vue d'evaluer les residus de sorgho, de
milperle et d'éleusine dans I'alimentation des ovins. Dans la première etude, les
animaux avaient ete soumis a une ration composee de 100 gde tourteau de
coton par jour et defoin (témoin) oudepaille d'une des cereales suivantes
offerte ad libitum: sorgho (blanc, SVI; ou rouge, DC75); milperle (blanc, SDMV
89004; ou rouge NCD2); éleusine (blanche, SDFM 63; ou rouge, 25C). Les
concentrations en azote et en parois cellulaires etaient differentes entre espèces
mais non entre varietes. Avec la teneur en azote la plus élevee et la
concentration en parois cellulaires la plus faible, l' éleusine etait plus volontiers
consommee (P<0,05) et donnait lieu a une retention d' azote maximum et une
189
digestibilite minimum des parois cellulaires. Dans la seconde experience, les
animaux etaient soumis a l'une des rations suivantes: Join plus 100 g de tourteau
de colon par jour (témoin); epis egrenes de sorgho blanc (SVI) ou rouge (DC75)
seuls ou avec 100 g de tourteau de colon par jour; ou epis egrenes d'eleusine
(25C). Les epis d'eleusine avaient la teneur la plus élevee en azote et la plus
faible en parois cellulaires, et etaient plus consommes et phis facilement digeres
(P<0,05). L'addition de tourteau de coton etait benefique pour les animaux et le
cultivar du sorgho SVI etait plus facilement digere que le DC75.
INTRODUCTION
The constraints to livestock production from feeding large quantities of fibrous
byproducts are known (Sundstol and Owen, 1984), as are interventions which
can ameliorate them. However, much of the information has been derived from
temperate crops and in circumstances where inputs, such as chemicals and
protein supplements, are available and affordable. In much of Africa maize,
sorghum and millet are the major cereal crops and there is little scope to
purchase inputs for livestock production. In some areas of Zimbabwe up to 50%
of dry-season feeding can come from crop residues.
In Zimbabwe maize is the preferred staple but because of low rainfall and
short grazing seasons in natural ecological regions IV and V (Johnson, 1987)
sorghums and millets are recommended by researchers and extension staff. Total
crop-residue production in 1989/90 from the three major cereals, based on
preliminary estimated forecasts of grain yield (Kossila, 1988; CSO, 1990),
amounted to more than 5.5 million tonnes. Methods for improving the utilisation
of maize stover have been reported (Manyuchi et al, 1990). Work is now in
progress to evaluate sorghum and millet residues as livestock feeds.
MATERIALS AND METHODS
Two experiments were conducted to measure intake, digestibility and nitrogen
retention (NR) of sorghum and pearl and finger millet residues.
In one experiment, 35 indigenous wethers (average initial liveweight 34 kg;
age about 18 months) were allocated at random to one of seven treatment groups
(five animals each):
• hay (control)
• white sorghum stover (SVI)
• red sorghum stover (DC75)
white pearl millet stover (SDMV 89004)
• red pearl millet stover (NCD2)
• white finger millet stover (SDFM 63)
red finger millet stover (25C).
All animals in this trial also received 100 g cottonseed meal (CSM) per day.
190
The second experiment used 30 of the wethers from the first experiment,
after they had grazed on veld for one month: their average initial liveweight was
31 kg. They were allocated at random to six treatments (five animals each):
hay plus 100 g CSM/day (control)
• threshed heads of white sorghum (SVT) with or without 100 g CSM/day
• threshed heads of red sorghum (DC75) with or without 100 g CSM/day
• threshed heads of red finger millet (25C), alone.
Cereal heads were threshed using a mechanical thresher. Residues were
milled using a 25-mm screen and offered to sheep ad libitum at 0800 and 1400
hours daily. Sheep were individually penned; water was always available. Intake
was measured after 21 days acclimatisation, after which 80% of ad libixum
intake was fed prior to measuring digestibility and nitrogen retention. A seven-
day period was allowed for adjustment to the digestibility crates. Faeces and
urine were weighed daily, subsampled and stored at -20CC to await analysis.
RESULTS
Experiment 1
Neutral detergent fibre (NDF) and nitrogen (N) contents of the stovers were
different between species (Table 1) but not between varieties within species.
Finger millet contained most N and least NDF. The hay used contained less N
and more NDF than the residues. Intake was highest (P<0.05) with finger millet
and lowest with hay and SDMV pearl millet (Table 2): differences between pearl
millet varieties may have been due to traces of mould in SDMV. Dry-matter
(DM) and organic-matter (OM) digestibilities were lowest for hay (P<0.05), and
NDF digestibility was lowest in the finger millets (P<0.05). (The differences in
digestibility between sorghum varieties were probably due to a higher
concentration of phenolics in DC75.) Nitrogen retention was greatest with finger
millet, especially 25C, and least with hay (P<0.05).
Experiment 2
The threshed stover heads contained about 70 g grain/kg DM. Finger millet
heads contained most N and least NDF (Table 1). Heads of red sorghum
contained more N than those of white sorghum. Intake was highest with ringer
millet heads and lowest with hay (P<0.01). CSM increased (P<0.05) intake of
the sorghum heads, especially DC75 (Table 3). DM and OM digestibilities were
greatest with finger millet and DC75 plus CSM and least with hay (P<0.05).
Intake and digestibility of both sorghums were enhanced by CSM; SVI was more
digestible than DC75. Digestibility of NDF was greatest with SVI plus CSM and
hay and least with DC75 alone and ringer millet (P<0.05). Nitrogen retention
was increased by CSM and finger millet (P<0.05).
191
Table 1. Chemical composition ofstovers and threshed heads
Chemical composition (g/kg DM)
Dry matter
(g/kg)
Neutral detergent
fibre
Organic
matterRoughage Nitrogen
Hay 941 6.1 861 940
Sloven
Sorghum
SVI 938 8.6 762 935
DC 75 932 8.8 765 923
Pearl millet
SDMV 89004 935 10.2 784 902
NCD2 938 10.4 777 901
Finger millet
SDFM63 918 15.5 605 901
25C 925 17.0 637 906
Threshed heads
Sorghum
SVI 917 8.5 710 946
DC 75 918 14.2 776 949
Finger millet
25C 888 18.9 434 929
DISCUSSION
The results confirm earlier reports (Smith and Balch, 1984) that low protein and
high fibre reduce the nutritional value of cereal residues. Intakes of the residues
used here were much higher than those reported in lambs receiving maize stover
supplemented with urea (Manyuchi et al, 1990) or CSM (Smith et al, 1990),
probably reflecting the relatively low N content of maize stover.
Quantities of threshed heads available are minimal compared to stover. The
retained grain in the heads (about 70 g/kg DM) would have contributed to their
acceptability as feed. The finger millet heads could probably be effectively used
as a supplement to dry-season grazing or stover diets.
In another study, the grains removed from sorghum (SVI) and pearl millet
(SDMV) stovers were compared as replacements for maize grain in high-energy
finishing diets for steers (Nengomasha et al, in press). The results indicate that
these two varieties can replace maize grain in fattening diets.
The study of sorghums and millets is continuing with emphasis on the
effects of agronomic and handling techniques on stover yield and quality.
192
Table 2. Voluntary intake, digestibility andN retention in sheepfed sorghum andpearl andfinger
millet stovers
Intake Digestibility (g/kg DM)
Neutral
N retention
Dry
matter
Organic
matter
detergent g/kgN
intakeRoughage g/day g/kg°'75 fibre g/day
Hay 690 49.4 456 483 554 1.78 213
Sorghum
SVI 874 61.1 548 559 583 4.03 352
DC 75 900 62.9 502 521 565 3.69 316
Pearl mulct
SDMV 89004 684 48.8 498 504 544 4.70 429
NCD2 957 66.8 510 528 570 3.65 292
Finger millet
SDFM63 1054 75.8 523 539 459 6.76 375
25C 1017 72.1 517 540 482 9.23 482
SE 40.6 3.1 0.66 0.65 0.96 0.46
Table 3. Voluntary intake, digestibility andN retention in sheepfed sorghum andfinger millet
threshed heads
Intake Digestibility (g/kg DM)
Neutral
N retention
Dry
matter
Organic
matter
detergent g/kgN
intakeRoughage g/day g/kg"-75 fibre g/day
Hay 708 57.4 492 521 481 3.54 378
Sorghum
SVI 1090 87.5 493 505 444 Z34 312
SVI + CSM 1262 101.2 563 585 528 5.63 392
DC 75 888 69.8 446 443 403 2.91 282
CD 75 + CSM 1141 89.3 513 531 443 7.20 341
Finger millet
25C 1409 110.3 570 589 413 9.27 428
SE 81.1 5.62 1.39 5.46 0.98 0.47
193
ACKNOWLEDGEMENTS
We thank Dr S C Gupta and SADCC/ICRISAT for supplying the residues. We
also thank Mr N Jele and his staff for care of the animals, and Mr J S Dube and
his staff for chemical analysis.
REFERENCES:
Central Statistical Office (CSO). 1990. Report ofCrop Forecasting Committee, March
1990. Government Printers, Harare, Zimbabwe. 1 p.
Johnson P (ed). 1987. Recommendationsfor cropping in the semi-arid areas ofZimbabwe.
Agritex, Harare, Zimbabwe. 97 pp.
Kossila V. 1988. The availability of crop residues in developing countries in relation to
livestock populations. In: Reed J D, Capper B S and Neate P J H (eds), Plant breeding
and the nutritive value of crop residues. Proceedings of a workshop held at ILCA
Addis Ababa, Ethiopia, 7-10 December 1987. ILCA (International Livestock Centre
for Africa), Addis Ababa, Ethiopia. pp. 29-39.
Manyuchi B, Ncube S and Smith T. 1990. Optimising crop utilization in Zimbabwe.
Animal Production 50:589 (Abstract).
Nengomasha E M, Hatendi P R, Gupta S C and Smith T. Sorghum and pearl millet as
energy substitutes for maize grain in high energy pen-fattening diets. In: Division of
Livestock and PastureAnnualReport. Department of Research and Specialist
Services, Harare, Zimbabwe (in press).
Smith T and Balch C C. 1984. Implications of a more widespread use of straw and other
fibrous by-products as feed. In: Sundstol F and Owen E (eds), Straw and otherfibrous
by-products as feed. Elsevier, Amsterdam, The Netherlands. pp. 575-604.
Smith T, Manyuchi B and Mikayiri S. 1990. Legume supplementation of maize stover. In:
Dzowela B H, Said A N, Asrat Wendem-Agenehu and Kategile J A (eds), Utilization
ofresearch results on forage and agricultural by-product materials as animalfeed
resources in Africa. Proceedings of the first joint workshop, held in Lilongwe,
Malawi, 5-9 December 1988. PANESA/ARNAB (Pasture Network for Eastern and
Southern Africa/African Research Network for Agricultural By-Products). ILCA
(International Livestock Centre for Africa), Addis Ababa, Ethiopia. pp. 302-320.
Sundstol F and Owen E (eds). 1984. Straw and otherfibrous by-products as feed.
Elsevier, Amsterdam, The Netherlands. 604 pp.
194
NON-CONVENTIONALFEED SOURCES AS SUPPLEMENTS TO
BEEF HEIFERS FED LOW QUALITY HAY
1 2 2I E J Iwuanyanwu , NN Umunna andN I Dim
National Agricultural Extension and Research Liaison Services
Ahmadu Bello University
PMB 1067, Zaria, Nigeria
Department of Animal Science
Ahmadu Bello University
PMB 1067, Zaria, Nigeria
ABSTRACT
During the dry season in the savannah region of Nigeria, low quality hay
constitutes an important source of energy for ruminants, especially cattle.
Because of its high fibre and low protein contents, the hay is poorly digested and
intake is consequently limited.
Grazing cattle, especially those managed under nomadic conditions,
commonly lose body weight during this time unless they are provided with some
form of protein supplement. Cottonseed and groundnut cakes are the traditional
supplements but their use is limited by several factors, one of which is that most
of tie oilseed cakes produced find their way into compound feed for
monogastric animals and so are now too expensive for use in cattle feed
supplements. For this reason, other non-conventional sources of protein
supplement need to be explored. Fertiliser grade urea with or without molasses
and bloodmeal with or without bonemeal, used as supplements, improve
digestibility and reduce weight loss in beef heifers fed low quality hay during the
dry season.
RESUME
Utilisation de sources non conventionneU.es a"aliments pour la
complementation des rations de genisses de race de boucherie recevant dufoin
de qualite mediocre
•
Au cows de la saison seche, lefoin de qualité médiocre constitue une importante
source d' énergie pour les ruminants, et notamment les bovins, dans la savane au
195
Nigéria. Etant donné que ce foin est riche en cellulose et pauvre en proteines, sa
digestibilite demeure faible et sa consommation est en conséquence limitee.
Les bovins élevés sur pâturage, et notamment par les éleveurs nomades,
perdent généralement du poids pendant la sécheresse, à moins d'avoir accès à
une complémentation proteique. Les tourteaux de coton et d'arachide constituent
les sources traditionnelles de complementation les plus fréquemment rencontrées
dans cette région. Malheureusement, leur utilisation est limitee par un certain
nombre de facteurs, notamment le fait que la plupart d'entre eux entrent
également dans les aliments composés des monogastriques et sont en
conséquence trop chers pour itre incorporés dans les rations des bovins. Il faut
donc rechercher d'autres sources de complements pour cette categorie
d'animaux. Cette étude a permis d'établir que l'addition ou non de mélasse à
l'urée utilisée dans la production d'engrais et la farine de sang additionnée ou
non de farine d'os permettaient d'accroître la digestibilite et de réduire les
pertes de poids des génisses de race de boucherie recevant du foin de qualite
médiocre au cours de la saison seche.
196
USE OF WHOLE SUNFLOWER SEEDS AND UREAAS
SUPPLEMENTS TO CROP-RESIDUE-BASED DIETS FOR
GOATS
A R Warambwa1 andLR Ndlovu2
Henderson Research Station
Private Bag 2004, Mazowe, Zimbabwe
^Department of Animal Science
University of Zimbabwe
PO Box MP 167, Mount Pleasant, Harare, Zimbabwe
ABSTRACT
The potential use of diets based on maize stover and groundnut hay with either
urea or sunflower seed as a supplement was investigated using indigenous Small
East African goats. Four female goats fitted with permanent rumen cannulae
were randomly assigned to a 2 x 2 change-over design to determine dry-matter
loss using the nylon-bag technique. The sunflower-supplemented diet contained
more readily degradable fraction than the urea-supplemented diet (11.45 vs
4.64%) but had a lower dry-matter degradation (45.08 vs 56.02%). In another
trial, 33 female goats were balanced for weight and assigned to two groups and
given one of the two diets for 16 weeks. Intake and liveweight changes were not
different between the two diets. Both diets were adequate to maintain weight.
RESUME
Utilisation de graines entieres de tournesol etd'uree comme compliments de
rations d base de residua de recolte chez les caprins
Des rations a base de paille de mdis et de fourrage d'arachide complementéd
avec de I'uree ou des graines de tournesol ont ete evaluees sur des petites
chevres d'Afrique de I'Est. Quatre femelles dans le rumen desquelles avaient &é
en permanence fixees des canules ont ete reparties au hasard selon un modele
croise en vue de determiner les penes de matiere sèche par la méthode des
sachets en nylon. II ressort des resultats enregistres que la fraction facilement
degradable etait plus importarue avec les graines de tournesol qu'avec I'uree
(11,45% contre 4,64%). Par ailleurs, le taux de la degradation de la matiere
197
seche etait plus faible avec le premier (45,08%) qu'avec le second type de
complement (56,02%). Dans un autre essat, 33 chevres avaient eté divisees en
deux groupes de poids homogene soumis chacun a I'une ou I'autre de ces deux
rations pendant 16 semaines. Ces deux regimes alimentaires permettaient en
outre aux animaux de maintenir leurpoids et n'etaient différents ni en ce qui
concerne la consommation, ni en ce qui concerne les variations de poids des
animaux.
INTRODUCTION
Nutrition is the main constraint to goat production in Zimbabwe (Manyuchi and
Sibanda, 1989) and stocking rates may be as high as 15 times the recommended
levels. As pressure on land continues to increase with the increasing population
(3.6% per year), especially in the crop-livestock areas, overgrazing in the wet
season does not allow sufficient weight carry-over for the dry season, leading to
weight loss and general low productivity. Results from the University of
Zimbabwe (Nyamangara and Ndlovu, 1991) show that goats lose weight even in
the wet season, especially when continuous rain restricts grazing time.
One possible solution is to provide supplementary feed. The resources
available in communal areas are mainly crop residues (maize and sorghum
stover and groundnut tops). Cereal stovers nave high fibre and low nitrogen
contents and thus low degradabilities in the rumen, and so are generally low in
nutritive value. Groundnut hay has higher nutritive value and has been found to
improve utilisation of stovers (Ndlovu and Hove, 1989). However, low nitrogen
diets supplemented with legume still need a source of readily fermentable
nitrogen to ensure adequate concentration of ammonia in the rumen (Preston,
1986). Urea used as a feed supplement, even in small amounts, can increase
fermentable nitrogen. There may also be a need to supply animals with
"by-pass" energy in the form of lipids. Most farmers in the communal areas
grow some sunflowers. Sunflower seed contains about 20% crude protein and
40% oil and its use in crop-residue-based diets could be beneficial.
The aim of this study was to characterise diets based on crop residues
supplemented with small amounts of urea or sunflower seed.
MATERIALS AND METHODS
Animals and diets
The experimental animals were indigenous female Small East African goats.
Two experimental diets, based on maize stover and groundnut hay, were
investigated; one (diet A) contained urea as a supplement, the other (diet B)
sunflower seed (Table 1).
198
Table 1. As-fed composition and chemical analysis of diets
Diet A Diet B
As-fed composition (%)
Groundnut hay 28.2 25.9
Maize stover 65.9 60.2
Urea 1.9
Sunflower seed - 10.3
Ground limestone 1.2 1.1
Salt 2.6 2.4
Vitamin/mineral mix 0.2 0.2
Chemical analysts (g/kg DM)
Dry matter 95.78 95.89
Crude protein 7. 17 8.45
Neutral detergent fibre 73.05 69.35
Acid detergent fibre 52.72 48.49
Ash 1.09 8.33
Fat L31 3^49
Dry-matter degradability
Dry-matter degradabilities of the diets were determined using four female goats
fitted with rumen cannulae and randomly assigned to a 2 x 2 change-over design.
Feed samples were milled to pass through either a 3-mm or a 1-mm screen to
assess the effect of particle size on degradability. Nylon bags (195 x 90 mm; pore
size, 38 u,m) containing 3 g of feed were incubated in the rumen of each goat.
Bags were withdrawn at 3, 6, 9, 12, 24, 48 and 72 hours, washed under running
tap water and dried at 60°C to constant weight. Dry matter was analysed at each
sampling time. Degradability was described using a derivation of the equation
described by 0rskov and McDonald (1979):
Amount degraded in time t = a + be
where:
a = readily degradable fraction (%)
b = extent of degradation (%)
c = rate of degradation
t = time (hours)
Intake and growth of goats
A total of 33 young indigenous female goats were stratified according to weight
and then randomly assigned to two groups. Goats with a liveweight less than
199
15.5 kg at the start of the trial were classified as light, the others as heavy. The
goats were housed in individual pens with concrete floors and received either
diet A or diet B for 16 weeks. Feed intake was recorded daily. Liveweight
changes were recorded fortnightly.
RESULTS
Dry-matter degradability
Results of the dry-matter degradability studies are shown in Table 2.
Diet B had a significantly (P<0.001) higher readily degradable fraction than
diet A. Screen size had an effect on degradability of diet B, but not of diet A.
There were significant diet and screen interactions (P<0.05). Within the 1-mm
screen size, diet B had higher (P<0.05) readily degradable values than diet A
There were no such differences with between samples milled through the 3-mm
screen.
Diet A had a higher extent of degradation than diet B (P<0.001). Within diet
A samples milled through a 1-mm screen had a higher extent of degradation
(P<0.05) than those milled through a 3-mm screen. Diet B was not affected by
screen size. Within both screens diet A had a higher extent of degradation
(P<0.05) than diet B.
Rate of degradation was similar for both diets and was not affected by
screen size.
Degradability value-.(%)
1-mm screen 3-mm screen
Readily degradable fraction (%)'
Diet A 3.42 5.85
DietB 14.37 8.54
Extent of degradation (%)'
Diet A 58.97 53.08
DietB 46.06 44.10
Rate of degradation'
Diet A 0.041 0.045
DietB 0.044 0.051
Table 2. Dry-matter degradability values ofcrop-residue-based diets supplemented with either
urea (diet A) or sunflower seed (diet B); feed samples milled through 1 -mm or 3-mm
* In the equation (amount degraded in time t = a + be-"), a = readily degradable fraction; b = extent of
degradation; c = rate of degradation; t = time
200
0.70 49.6 0.014
0.66 50.7 0.013
035 1.21 0.007
0.84 483 0.017
052 52.1 0.010
0.35 1.21 0.007
Table 3. Effect of diet and weight category ofgoats on liveweight change, feed intake and
efficiency ofproduction for goats fed crop-residue-based diets supplemented with either
urea (diet A) or sunflower seed (diet B)
Total liveweight Feed efficiency
change Total intake (liveweight gain/feed(kg) (kg) '"take)
Diet A
DietB
SE
Light goats
Heavy goats
SE
Animal responses
Feed intake and growth responses of the animals fed the experimental diets are
shown in Table 3. There were no differences in liveweight changes within diet
groups or weight categories. There were no differences in daily intake between
diets but, as expected, heavier animals consumed more than light animals
(P<0.01). Feed efficiency did not differ within diet or weight groups.
DISCUSSION
Dry matter degradabilities
The inclusion of sunflower seed in diet B was meant to increase both energy and
protein content of the diet. This was, however, not achieved as the diets were
similar in terms of chemical composition. Adding a source of oil to diets based
on maize stover is supposed to alter the glucogenic ratio in volatile fatty acids in
favour of propionate (Preston and Leng, 1987) thus leading to higher gains of
goats on such diets. However, the maximum recommended level of oil inclusion
is 5%, as higher values tend to depress intake and reduce microbial activity
(Jenkins and Palmquist, 1984). Adding 12% unprocessed sunflower seeds
supplied 3.5% oil inclusion. As this was less than the maximum recommended
level, the lack of response by the goats was probably due to poor degradation of
the unprocessed sunflower seed. Sunflower seed has a thick seed coat which
might be resistant to degradation by rumen bacteria. It is also possible that the fat
in the sunflower seed reduced hydrophility of feed particle surfaces and
prevented further microbial adhesion and digestion (Lindberg, 1985).
According to Preston (1986), if extent of degradation of roughage after 48
hours is less than 40-50%, then it is not worth feeding. Degradability of both
201
diets A and B had exceeded 40% by 48 hours; these diets thus appear to be
promising feeds.
Effect of screen size
Milling samples through a 3-mm screen decreased the readily degradable
fraction in diet B and the extent of degradation in diet A compared with the
1-mm screen. Decreasing screen (feed particle) size increases the surface area
exposed to microbial activity and hence results in higher degradation values
(0rskov, 1975). However, in other instances screen size had no effect. Lindberg
(1984) postulated that lack of effect due to particle size could be due to reduced
inflow of rumen liquor and microbes into the nylon bags. Other workers (van
Keuren and Heinemann, 1962) also found no significant effects due to screen
size. Differences in dry-matter disappearance due to screen size may be
noticeable at short incubation times, but prolonged incubation reduces the
magnitude of differences in digestibility (McLeod and Minson, 1969).
Animal responses
Goats on both diet A and B managed to maintain weight throughout the 16-week
experimental period. The results obtained are in contrast to work done by Prasad
and Mandebvu (Makoholi Research Station, Masvingo, Zimbabwe) who
reported weight loses (-14 and -11 g/d) when groundnut and siratro hay,
respectively, were fed with maize stover. However, Banda and Ayoade (1986)
reported that groundnut haulms significantly improved liveweight gains in goats
fed maize bran.
CONCLUSIONS
Although neither diet could support goat production, both were adequate to meet
the maintenance requirements, and this is a positive step in improving goat
productivity in critical periods (hot wet and cold dry seasons) when the goats
lose weight.
REFERENCES
Banda J L L and Ayoade J A. 1986. Leucaena leaf hay (Leucaena leucocephala cv Peru)
as protein supplement for Malawian goats fed chopped maize stover. In: Preston T R
and Nuwanyakpa M Y (eds), Towards optimal feeding of agricultural byproducts to
livestock in Africa. Proceedings of a workshop held at the University of Alexandria,
Egypt, October 1985. ARNAB (African Research Network for Agricultural
By-products). ILCA (International Livestock Centre for Africa), Addis Ababa,
Ethiopia. pp. 124-128.
202
Jenkins T C and Palmquist D L. 1984. Effect of fatty acids or calcium soaps on rumen and
total nutrient digestibility of dairy rations. Journal ofDairy Science 67:978-986.
van Keuren R W and Heinemann W W. 1962. Study of the nylon bag technique for in vivo
estimation of forage digestibility. Journal ofAnimal Science 21:340-345.
Lindberg J E. 1984. Nitrogen metabolism in sheep. A comparison between rumen
degradability of nitrogen and organic matter in sacco and in vivo in sheep fed rations
with hay, barley and various protein supplements. Swedish Journal ofAgricultural
Research 14:37^3.
Lindberg J E. 1985. Estimation of rumen degradability of feed proteins with the in sacco
technique and various in vitro methods. A review. ActaAgriculturae Scandinavica,
Supplementum 25:64-94.
Manyuchi B and Sibanda S. 1989. Research on crop residues and agro-industrial
byproducts as livestock feed in Zimbabwe. A review. ARNAB Newsletter 9(2): 1-11.
ARNAB (African Research Network for Agricultural By-products). ILCA
(International Livestock Centre for Africa), Addis Ababa, Ethiopia.
McLeod M N and Minson D J. 1969. Sources of variation in the in vitro digestibility of
tropical grasses. Journal of the British Grassland Society 24:244-249.
Ndlovu L R and Hove L. 1989. Effects of feeding graded levels of groundnut hay on the
utilization of veld hay by goats in Zimbabwe. In: Wilson R T and Azeb Melaku (eds),
African small ruminant research and development. Proceedings of a conference held
at Bamenda, Cameroon, 18-25 January 1989. African Small Ruminant Research
Network. ILCA(International Livestock Centre for Africa), Addis Ababa, Ethiopia.
pp. 192-203.
Nyamangara M E and Ndlovu L R. 1991. Feeding behaviour, feed intake and
characteristics of the diets of indigenous goats grazed on natural vegetation in a high
rainfall area of Zimbabwe. Zimbabwe Journal ofAgriculturalResearch (accepted, in
0rskov E R. 1975. Manipulation of rumen fermentation for maximum food utilization.
WorldReview ofNutrition and Dietetics 22:152-182.
0rskov E R and McDonald 1. 1979. The estimate of protein degradability in rumen from
incubation measurements weighted according to the rate of passage. Journal of
Agricultural Science, Cambridge 92:499-503.
Preston T R. 1986. Better utilization of crop residues and by-products in animalfeeding:
Research guidelines. 2 A practical manualfor research workers. FAO Animal
Production and Health Paper 50/2. FAO (Food and Agriculture Organization of the
United Nations), Rome, Italy. 154 pp.
Preston T R and Leng R A 1987. Matching ruminantproduction systems with available
resources in the tropics and subtropics. Penambul Books, Armidale, New South
Wales, Australia. 245 pp.
203
204
VELD HAY AS FEED FOR MATEBELE GOATS DURING THE
LAST TRIMESTER OF PREGNANCY
L MSibanda, L R Ndlovu1 andMJBryant2
Department of Animal Science
University of Zimbabwe
PO Box MP 167, Mount Pleasant, Harare, Zimbabwe
Department of Agriculture
University of Reading
Earley Gate, Reading RG6 2AT, UK
ABSTRACT
Under natural husbandry conditions, kid birth weights and growth rates are
lowest in the dry season when feed is scarce and of very low quality. The
experiment investigated the potential of veld hay supplemented with lucerne hay
as feed for pregnant goats. The digestibility and metabolisable energy (ME)
content of the forages were estimated from the dry-matter (DM) disappearance,
which was measured by the rumen-bag technique. Forty-five multiparous
Matebele goats (mean liveweight 35.1 kg) in the 14th week of gestation were fed
at one of three levels: low (L: 0.26 MJ ME/kg LW075), medium (M: 1.5 x L) and
high (H: 2 x L, with veld hay offered ad libitum). Maize grain (13.2 MJ ME/kg
DM), lucerne hay (7.2 MJ ME/kg DM) and veld hay (5.52 MJ ME/kg DM) were
fed at 20, 24 and 56%, respectively, of the total metabolisable energy per
treatment. The goats were weighed and body-condition scored (scale 1-10)
weekly during pregnancy and within eight hours of parturition.
Results for 42 goats that gave birth to single living kids are presented. Mean
ME intakes during pregnancy were 10.23, 5.91 and 4.08 MJ/day (SE=0.261) for
H, M and L groups, respectively. Between week 15 and kidding, changes in net
liveweight were +4.8, +0.9 and -1.5 kg (SE=0.86), and changes in body
condition were -0.4, -1.6 and -1.3 (SE=0.27), for the goats on H, M and L
treatments, respectively. Kid birth weights were 3.18, 2.92 and 2.89 kg
(SE=0.154). These birth weights were higher than normally realised in the dry
season under natural rearing conditions. It is concluded that Matebele goats can
eat sufficient quantities of veld hay to meet energy requirements during
pregnancy.
205
RESUME
Alimentation de chevres Matebele avec dufourrage de veld au cours des trots
derniers mois de gestation
Dans les conditions normales d'elevage, lepoids des chevreaux a la naissance et
leur vitesse de croissance tombent au plus bas au cours de la saison seche, au
moment ou les aliments du bétail sont rares et de tres mauvaise qualite. Cette
expérience examine I'effet de I'alimentation de chevres en gestation avec du
fourrage de veld complémente avec du foin de luzerne. La digestibUite des
fourrages et leur teneur en énergie metabolisable (EM) ont été estimées apartir
du taux de degradation de la matiere seche, mesurépar la technique des sacs en
nylon introduits dans le rumen. Quarante cinq chevres Matebele pesant en
moyenne 35,1 kg et qui se trouvaient dans leur 14* semaine de gestation ont été
divisées en trois groupes. Chaque lot a été soumis a I'un ou I'autre de trois
régimes alimentaires caracterisés par leur teneur en énergie, laquelle était faible
(F: 0,26MJEM/kgPV°'75), moyenne (M: 1,5 xF) ou élevée (E: 2xFavec du
fourrage de veld ad libitum). Le mats grain (13,2 MJ EM/kg MS), lefoin de
luzerne (7,2 MJEM/kg MS) et lefoin de veld (5,52 MJEM/kg MS) constituaient
respectivement 20, 24 et 56% de Vénergie metabolisable contenue dans chaque
ration. Les chevres étaient pesées et leur état d'engraissement enregistré unefois
par semaine au cours de la gestation puis dans les huit heures précédant la
parturition.
Les resultats presentes ici portent sur les 42 chevres qui avaient donné
naissance a un seul chevreau vivant au cours de cette expérience. L'ingestion
moyenne d'EMpendant la gestation était de 10,23; 5,91 et 4,08 MJ/j (erreur
type=0,261) pour les lots soumis respectivement aux niveaux faible, moyen et
élevé d'énergie. DelalS1 semaine de gestation a la parturition, les variations
de poids vifnet étaient respectivement de +4,8; +0,9 et —1,5 kg (erreur
type=0,86) avec des variations correspondantes de I'état d'engraissement égales
a -0,4; -1,6 et-1,3 (erreur type-0,27). Les poids a la naissance des chevreaux
étaient de 3,18; 2,92 et 2,89 kg (erreur type=0,154) respectivement pour les
niveaux faible, moyen et élevé d'énergie. Ces valeurs étaient supérieures aux
chiffres habituellement enregistrés en saison seche dans les conditions normales
d'élevage. Les chevres Matebele en gestation peuventpar consequent
consommer suffisamment defoin de veldpour couvrir leurs besoins en inergie.
INTRODUCTION
Goats play a vital role in the livelihood of smallholder farmers in Zimbabwe.
Over 70% of the national goat population are found on communal lands within
agro-ecological zones IV and V (Vincent and Hack, 1960). As these areas are
generally unsuitable for cropping, livestock rearing on natural vegetation is the
major agricultural enterprise.
206
The natural vegetation of these semi-arid areas of Zimbabwe (commonly
referred to as sweetveld (Rattray, 1957)) consists mostly of palatable annual
grasses which goats willingly graze in the rainy season when they are nutritious
(high protein content) and abundant (Nyamangara, 1990). However, during the
dry season the grasses are very mature and of low palatability. Moreover, the
trees and bushes on which the goats rely for browse shed their leaves. Elliot and
Fokkema (1961) showed that the dry-matter intake of range livestock in
Zimbabwe during the dry season is unlikely to exceed 1.5%, and may be as low
as 1.2%, of body weight. This energy and protein deficiency causes weight loss
in all livestock, but the effects are particularly severe in goats. Seventy per cent
of the indigenous Matebele goats in the communal areas kid in the dry season;
consequently, kid birth weights and growth rates are low (<2 kg and 40 g/day)
and kid survival rates below 65% are not uncommon (Ndlovu and Royer, 1988).
Adequate nutrition of goats during pregnancy and lactation can improve kid
birth weights and survival rates (Sibanda, 1990). Veld hay, harvested during the
rainy season, is a potential low cost feed resource for the dry season, but the
responses of pregnant goats to diets based on veld hay are not known. The study
reported here examined the effects of three levels of feeding on doe liveweight
and body-condition score changes and kid birth weights.
MATERIALS AND METHODS
Location
The experiments were conducted at the former Thuli Breeding Station, Guyu,
situated within agro-ecological zone V in Matebeleland Province, south-west
Zimbabwe. Total rainfall during the study year (1989) was 362 mm. Mean
maximum and minimum temperatures were 28 and 13°C, respectively.
Experimental diet
The experimental diets consisted of maize grain, lucerne hay and veld hay,
providing 20, 24 and 56%, respectively, of the total metabolisable energy. Three
levels of feeding were investigated: the low level treatment (L) allowed 0.26 MJ
ME/kg LW0'75; the medium level treatment (M) was calculated as 1.5 x L; and
the high level treatment (H) was calculated as 2 x L for the purposes of
establishing the allowance of maize grain and lucerne, while veld hay was given
ad libitum at 1.4 times the previous day's intake.
Feedstuffs
Lucerne hay and veld hay were obtained from Aiselby Municipality Farm,
Bulawayo, which is in the same agro-ecological zone as Guyu. The lucerne was
207
Table 1. Chemical composition ofmaize grain, lucerne hay and veld hay
Dry matter
(g/kg)
Chemical composition (g/kg DM)
Neutral detergent
fibreFeed Ash Crude protein
Maize grain
Lucerne bay
Veld hay
90.0
90.1
91.2
1.6 8.2
18.1
128
9.5
10.8
53.8
72.6
harvested at the early flowering stage, left to wilt overnight, baled and then
heat-dried in a barn. The veld hay was made from natural annual grasses
growing on cleared rangelands during the rainy season. The grass was baled and
then dried in the same manner as the lucerne.
The dry-matter, ash, crude-protein and neutral detergent fibre contents of
the feeds tuffs were determined and are shown in Table 1.
The rumen degradabilities of the lucerne hay and the veld hay were
established using the nylon-bag technique (Mehrez and 0rskov, 1977). Four
individually-penned, non-pregnant multiparous indigenous Matebele does fitted
with permanent rumen cannulas (40 mm diameter) were used in a 2 x 2 cross
over design that investigated the degradability of the two feedstuffs when the
does were fed at the low and medium feeding levels. The goats were offered the
diets for three weeks before any measurements were made. Water and a
salt-mineral lick were freely available at all times.
Representative samples of the two hays were ground through a 3-mm screen
using a laboratory hammer mill. Nylon bags containing 4 g of the sample were
suspended in the rumen for 3, 12, 24, 36, 48, 60 and 72 hours. After withdrawal,
the bags were hand washed in cold water for 30 minutes. A further feed sample
was used to determine the amount of soluble material by soaking in water before
washing. All the bags were then dried at 60°C to constant weight.
The rumen degradability of the feeds was calculated from the percentage
dry-matter loss from the incubated samples, as described by the mathematical
model p = a + b(l - e-0') (0rskov and McDonald, 1979), where p is the
percentage dry-matter loss at time t, (a + b) defines the maximum potential
degradability (the asymptote) and c is the rate constant of b.
Feeding trial
Forty-five multiparous Matebele goats that had been synchronised for oestrus
using progesterone-impregnated sponges, mated after oestrus and diagnosed
pregnant by consistently high plasma progesterone concentrations, were
individually penned and randomly allocated to one of the three feeding levels
from week 14 of gestation. Maize grain and lucerne hay were offered at the same
time (0800 hours) and veld hay for the M and L groups was offered in two
208
portions (at approximately 1000 and 1500 hours). Refused forage was collected
and a representative sample analysed for crude-protein and neutral detergent
fibre contents. Water and a salt-mineral lick were always available.
Does were weighed and body-condition scored (Honhold et al, 1989) at
weekly intervals. Kids were weighed within eight hours of birth.
Statistical analysis
Data were analysed by the method of least squares analysis of variance using
general linear model procedures (SAS, 1986). Post-kidding weights and body-
condition scores were adjusted using the initial weights and scores as covariates
RESULTS
Rumen degradation of lucerne hay and veld hay
The degradability characteristics of the forages are shown in Table 2. Feeding
level had no effect on any of the parameters. The lucerne hay contained more
soluble material and was degraded at a more rapid rate than the veld hay.
Table 2. Dry-matter degradability constants of lucerne hay and veld hay at low and high feeding
levels
Degradability constants
Feed Feeding level a b c
Lucerne hay Low 24.43 40.58 0.0926
Lucerne hay High 24.05 40.12 0.0901
Veld hay Low 14.52 56.65 0.0392
Veld hay High 14.90 54.24 0.0423
From the equation p = a + b(l-e )
where:
p = dry-matter loss (%)
a = readily degradable fraction (%)
b = potentially degradable fraction (%)
c = rate of degradation of the b fraction
t = time (hours)
The effective degradability of organic matter (P) was calculated as from the
equation P = a + {bc/(c + ki)}, where ki is the passage rate of digesta from the
rumen. As ki was not determined in this experiment, P was calculated for a
range of it; values, as shown in Table 3. The mean P values were then used to
provide an estimate of the ME values of the two forages, assuming that P is
equivalent to organic matter digested (OMD%). The OMD% was converted to
209
Table 3. Derivation ofmetabolisable energy values for lucerne hay and veld hay from potential
organic matter degraaability parameters
turnover rate
Rumen
ME
(MJ/kg DM)C
Mean ME
(MJ/kg DM)Feed (ki) OMD%"
DOMD%b
Lucerne hay 0.03 56.64 51.26 7.69
0.04 52.31 47.34 7.10 7.20
0.05 50.33 45.55 6.83
Veld hay 0.025 43.86 39.13 5.87
0.03 41.69 37.20 5.58 5.52
0.04 38.17 34.05 5.11
* OMD% is effective OM degradability = a + {bc/(c + ki)}
b DOMD% = OMD% (100 - ash%)/100 (MAFF, 1984: equation 55)
c ME = 0.15 DOMD% (MAFF, 1984: equation 58)
digestible organic matter in the dry matter (DOMD%) using the equation
DOMD% = OMD% (100 - ash%)/100 (MAFF, 1984: equation 55). ME was then
calculated as ME = 0.15 DOMD% (MAFF, 1984: equation 58). The ME values
of lucerne hay and veld hay are shown in Table 3.
Feeding trial
Two does gave birth to twins and a third was pseudo-pregnant. The other 42 does
gave birth to single, living kids; results from these does (14 per treatment) are
shown in Tables 4 and 5.
The mean crude-protein and neutral detergent fibre contents of the refused
veld hay from the H treatment were 125 and 756 g/kg DM, respectively,
compared to 128 and 726 g/kg DM for the offered material. Therefore there was
little evidence of selective feeding. The H treatment does were able to consume
36 g DM/kg liveweight on average over the period of the experiment (Table 4).
Table 5 shows the liveweight changes and body-condition scores of the
does, and the birth weights of the kids. Both M and H treatment does showed a
net gain in liveweight over the course of gestation, while the L treatment does
lost a small amount of weight. Only H treatment does maintained their body
condition. There were no significant treatment effects upon kid birth weight.
Although there was a trend for birth weight to decline with energy intake, the
differences were small compared to the very large differences in energy intake.
DISCUSSION
The ME values estimated for both hays are lower than the values found by Topps
and Oliver (1966). The differences could be attributed to many factors, including
210
Table 4. Least-squares meanfeed intakes ofgoats during late gestation
High
feeding level
Medium
feeding level
Low
feeding level SE
Number Of animals 14 14 14
Daily dry-matter intake
Maize grain (g/head) 180 107 74 3.9
Lucerne hay (g/head) 370 220 150 7.4
Veld hay (g/head) 930 520 360 34.4
Total (g/kg) 36 24 16 0.82
Daily ME intake
MJ/head 10.23 5.91 4.08 0.261
MJ/kgLW075 0.58 0.37 0.26 0.011
Table 5. Least-squares .mean doe liveweights and body condition scores andlad birth weights
High
feeding level
Medium
feeding level
Low
feeding level SE
Number of animals 14 14 14
Liveweight (kg)
Week IS 36.4 33.1 35.6 1.45
Post-kidding 39.8 36.0 33.6 0.92
Net change 4.8 0.9 -15 0.86
Body-condition score*
Week 15 5.6 5.4 5.4 0.27
Post-kidding 5.2 3.9 4.2 0.27
Net change -0.4b -1.6 -13 0.27
Kid birth weight (kg) 3.18 2.92 2.89 0.154
"On a scale of 1 (severely emaciated) to 10 (over-fat)
Not significantly different from zero
the degree of maturity of the forages at cutting and the methods of preservation,
as well as the methodologies of establishing the energy values.
Despite the poor digestibility values of the forages, the goats were able to
achieve high levels of intake. The intakes achieved by the H treatment does were
well in excess of the 3% of liveweight considered by Devendra and Bums (1983)
to be the maximum achievable. These high intakes were achieved without
recourse to selection, a characteristic of goats offered poor quality forages
(Wahed et al, 1990). The lack of selection could be a reflection of the very poor
quality of the veld hay.
211
The net liveweight gains of H and M treatment does indicate the adequacy
of nutrient supply for maintenance and production on these treatments. Does on
the L treatment utilised body tissue to support the demands of the foetus, so this
treatment had little effect on birth weight. The mean birth weights on all three
treatments were greater than those reported by Tawonezvi and Ward (1987) for
single kids from Matebele goats under a semi-intensive system on-station.
CONCLUSIONS
Veld hay, even of poor digestibility, supplied as a major part of the diet, can be
eaten in sufficient quantities to support the energy needs of Matebele goats in
late pregnancy.
ACKNOWLEDGEMENTS
Funding for this work was provided by the International Development Research
Centre (IDRC), Canada, and the University of Zimbabwe Research Board.
REFERENCES
Devendra C and Burns M. 1983. Feeding and nutrition. In: Goat production in the tropics.
Commonwealth Agricultural Bureaux, Farnham Royal, Slough, UK. pp. 90-115.
Elliot R C and Fokkema K. 1961. Herbage consumption studies on beef cattle. Rhodesia
Agricultural Journal 58:124.
Honhold N, Petit H and Halliwell R W. 1989. Body condition scoring system for goats.
TropicalAnimal Health andProduction 21:121-127.
MAFF (Ministry of Agriculture, Fisheries and Food). 1984. Energy allowance and
feeding systems for ruminants. 2nd edition. Chalcombe Publications, Marlow, UK.
85 pp.
Mehrez A Z and 0rskov E R. 1977. A study of the artificial fibre bag technique for
determining the digestibility of feeds in the rumen. Journal ofAgricultural Science,
Cambridge 88:645-650.
Ndlovu L R and Royer V. 1988. A comparative study of goat productivity in three
different regions of Zimbabwe. In: Harrison J (ed), Proceedings of a workshop on
goat development, 11-13 January 1988. French Embassy, Harare, Zimbabwe.
pp. 55-61.
Nyamangara M E. 1990. Feeding behaviour, chemical composition of diet andfeed intake
in indigenous goats raised on natural vegetation. MPhil Thesis. University of
Zimbabwe, Harare, Zimbabwe. 121 pp.
0rskov E R and McDonald I. 1979. The estimation of protein degradability in the rumen
from incubation measurements weighted according to rate of passage. Journal of
Agricultural Science, Cambridge 92:499-503.
212
Rattray J M. 1957. The grasses and grass associations of Southern Rhodesia. Rhodesia
Agricultural Journal 54:197.
SAS (Statistical Analysis Systems Institute Inc). 1986. SAS users' guide. SAS, Cary, North
Carolina, USA.
Sibanda R. 1990. Productivity of indigenous goats under an accelerated kidding
management system. MPhil Thesis. University of Zimbabwe, Harare, Zimbabwe.
93 pp.
Tawonezvi H P R and Ward H K. 1987. Productivity of indigenous sheep and goats. 2.
Environmental influences on performance of goats. Zimbabwe Journal ofAgricultural
Research 25:51-58.
Topps J H and Oliver J. 1966. Animalfoods ofCentral Africa. Rhodesia Agricultural
Journal Technical Handbook 2. Government Printer, Salisbury, Rhodesia [now Harare,
Zimbabwe]. p. 58.
Vincent V and Hack H R. 1960. Land use and recommendedfarming systems for different
land capability classes in different areas ofSouthern Rhodesia. Annual Conference of
the Professional Officers of the Department of Research and Specialist Services.
Government of Southern Rhodesia, Salisbury, Southern Rhodesia [now Harare,
Zimbabwe]. pp. 16-27. [ILCA library accession (microfiche) number 56017]
Wahed R A Owen E, Naate M and Hosking J B. 1990. Feeding straw to small ruminants:
effect of amount offered on intake and selection of barley straw by goats and sheep.
Animal Production 51:283-289.
213
214
FITTING FORAGE LEGUMES INTO THE CROPPING
SYSTEMS OF SEMI-ARID TANZANIA
ML Kusekwa, R S Kyamanywa andMD Ngowi
Livestock Production Research Institute (LPRI)
Ministry of Agriculture
PO Box 202, Mpwapwa, Tanzania
ABSTRACT
Forage legumes were grown as intercrops with maize, sorghum and bullrush
millet, and maize was planted in alleys ofLeucaena, for two growing season
(1988/89 and 1989/90) at Mpwapwa, Tanzania. The objective was to determine
the best entry points of these legumes into the crop-livestock systems of
semi-arid Tanzania.
Cereal grain yields were not significantly depressed by the presence of
forages, pointing to the possibility of introducing forages to the cereal-cropping
systems existing in semi-arid Tanzania, through such methods as intercropping
and alley cropping.
RESUME
Introduction de légumineusesfourragères dans les systèmes agraires de la
zone semi-aride en Tanzanie
Des essais ont eté effectués en vue de determiner la meilleure manière
d'introduire des legumineuses dans les systèmes agraires mixtes de la zone
semi-aride de la Tanzanie. Dans le cadre de ces travaux, des legumineuses
fourragères ont eté intercalées entre des cultures de maïs, de sorgho et de mil
chandelle et du maïs a eté semé entre des haies de Leucaena pendant deux
saisons de croissance (1988/89 et 1989/90) à Mpwapwa (Tanzanie).
Il ressort des résultats enregistrés que la présence de plantes fourragères
n'entraînait aucune baisse significative de la production de céréales, ce qui
signifie que I'on peut introduire ces espèces végetales dans les systèmes à base
de céréales de la zone semi-aride de la Tanzanie en utilisant la technique des
cultures intercalaires ou en couloirs.
215
INTRODUCTION
It is common practice, in semi-arid Tanzania, for grazing lands to be taken for
crop growing and so for livestock production to be pushed out to poorer, less
productive lands, where rainfall is unreliable. In these areas, sound land-use
practices, aimed at economically using the land resources at a sustainable level,
need to be developed and employed. One such practice is to produce more good
quality forage feed within the existing crop-livestock systems.
Forage legumes have played an important role in raising the productivity of
farming in temperate areas, a role which has yet to be clearly demonstrated for
the tropics. The primary role of the legumes is fixation of atmospheric nitrogen;
this leads to improved soil fertility, enhanced forage and mulching quality
(Tothill, 1986), and also to a supply of high quality feed for ruminants. In
Tanzania, semi-arid areas are characterised by small-scale mixed crop-livestock
farming systems. In such systems, forage legumes could be integrated into both
the crop and the livestock components. In the crop phase, legumes can reduce
the rate of decline of soil fertility, or even enhance crop yields, and can also
reduce the length of the fallow period. In the pastoral phase, legumes contribute
to better quality and use of crop residues and of natural forages on fallow land
(Kusekwa, 1990).
This paper discusses the testing of best-bet legumes for semi-arid Tanzania
under two cropping systems with a view to determining their possible entry
points into the crop-livestock farming systems in the area.
MATERIALS AND METHODS
The work was carried out at the Livestock Production Research Institute,
Mpwapwa, Tanzania (6° 20' S; 36° 30' E; altitude 1100 m). Annual rainfall here
is 700 mm, with 90% of the rain falling during December-April. Maximum and
minimum temperatures are 27.5 and 15.5 °C, respectively.
The cereals used in the study were varieties of maize, sorghum and millet
commonly grown in the area. The maize and sorghum varieties used were early
maturing (80 days): the millet (a local variety) took about 100 days to mature.
The legumes used were best-bet forage legumes: Stylosanthes hamata
(Verano stylo): S. scdbra (Seca stylo); Lablab purpureus (Rongai and Red);
Macroptilium atropurpureum (Siratro). Neonotonia wightii (Tinaroo glycine) and
Leucaena leucocephala (Peru).
Intercropping trial
The six forage legumes were grown as intercrops with the three cereal crops
commonly grown in central Tanzania, during the 1988/89 growing season. The
cereals and legumes were planted 30 cm apart, in rows 90 cm apart. The split
216
plot design was used, with the cereals making up the main plots and the legumes
the subplots; the control was cereal with no legume. In anticipation of severe
competition for nutrients by the intercrops, phosphorus and nitrogen fertilisers
were applied as recommended for the area, 40 kg P/ha as triple superphosphate
(46% P2O5) and 42 kg N/ha as calcium ammonium nitrate (26% N). Nitrogen
was split-applied at active vegetative growth and then at the pre-ear-emergence
stages of the cereals.
During the 1989/90 growing season, two legumes were dropped from the
study: Rongai lablab because of severe smothering effects on the cereals; and
Seca stylo because of its poor survival, caused by termite damage. The
established legumes were slashed to ground level before the cereals were
sod-seeded at the usual spacing of 30 x 90 cm.
Alley-cropping trial
For the alley-cropping study, an area was selected from a previously established
5-ha Leucaena field, in which rows oiLeucaena were spaced 3, 4, 5 and 6 m
apart; maize was sown in the alleys at 30 x 90 cm spacing. The rows of
Leucaena were cut back to stubble heights of 25, 50 and 75 cm, making the
study a four alleys x three cutting heights combination of treatments. Maize was
fertilised with phosphorus and nitrogen in the first year of the study (1988/89),
but in the subsequent year (1989/90) fertiliser N was withdrawn as fertility
build-up was anticipated from the effects of mulching. During the 1989/90
growing season, interface competition was also investigated by looking at yields
of grain and stover in relation to distances of the maize rows from the Leucaena
rows.
Statistical analysis
Statistical analysis was performed with Instat (PC version, June 1987: Statistical
Service Centre, University of Reading, UK).
RESULTS AND DISCUSSION
Intercropping trial
In 1988/89, grain and stover yields of the different cereals were significantly
(P<0.05) different (Table 1). However, the type of cereal did not significantly
effect legume dry-matter (DM) production, which was about 3 t/ha in each case.
Millet and sorghum yielded higher (P<0.05) total forage (stover + legume
herbage) than maize. The trends in yield of cereal grain and stover and legume
forage during the 1989/90 growing season were similar to those in the 1988/98
growing season.
217
Table 1. Effects of intercropping forage legumes with cereals on grain-stover and
legume-herbage yields, 1988/89 and 1989/90 growing seasons
Yield (t/ha)
Cereal
Cereal grain
(air dried)
Cereal stover
(DM)
Legume herbage
(DM)
Total forage
(stover + legume) (DM)
1988/89 growing iseason
Maize 5.6 3.9 3.2 7.1
Sorghum 2.0 5.0 3.4 8.4
Millet 3.7 5.7 3.2 8.9
Mean 3.77 4.87 3.27 8.07
LSD (5%) 0.69 0.64 OS 1.33
1989/90 growing season
Maize 4.5 3.4 3.5 6.9
Sorghum 3.1 5.5 2.9 8.4
Millet 3.9 6.0 2.9 8.9
Mean 3.83 4.97 3.10 8.07
LSD (5%) 0.59 0.79 0.46 1.41
The grain yield did not seem to be depressed by the presence of intercrops
as the yields were high compared with the area averages which, according to the
Mpwapwa District Agricultural Officer, are 3.0 t/ha for maize, IS t/ha for
sorghum and 2.5 t/ha for millet. This result points to the possibility of
introducing forages to the cereal cropping systems of the area, especially
dual-purpose legumes such as lablab. Traditionally, agropastoralists in this area
usually intercrop cereals with grain legumes. This could be realised if and when
farmers can be shown that overall productivity of the land is increased when
forage from stover and legume is put to proper use such as maintaining a
productive animal.
Table 2 shows the effects of forage legumes on grain and stover yields and
legume herbage production when intercropped with cereals. Rongai lablab
appeared to depress grain yield of the cereals the most, probably as a result of
smothering effects of the lablab on any companion plants, while Siratro and
Verano and Seca stylo seemed to enhance grain yield, which indicated that there
was some soil fertility build-up in plots under these legumes. In general, the
more DM produced by the legume the more the depressing effect on grain yield.
It is evident that the inclusion of forage legumes in cereal plots led to
increased quantity and quality of the total forage (stover + legume herbage)
produced. Stovers alone had an average crude protein (CP) content of 2.4%
while legumes averaged 13.9% CP. Such an improvement in the quantity and
quality of the feed resource is seen as the key to improved nutrition of the
218
Table 2. Effects offorage legumes on grain, stover and legume-herbage yields when intercropped
with cereals, 1988189 and 1989/90 growing seasons
Yield (t/ha)
Total forage
Cereal grain
(air dried)
Cereal stover
(DM)
Legume herbage
(DM)
(stover + legume)
Cereal (DM)
1988/89 growing season
No legume 3.7 5.1 - 5.1
Verano stylo 4.2 5.8 1.0 6.8
Lablab (red) 3.4 5.1 2.1 7.2
Lablab (Rongai) 28 4.3 9.8 14.1
Siratro 4.2 5.8 4.7 10.5
Tinaroo glycine 3.7 5.2 1.1 6.3
Seca stylo 4.1 5.6 1.0 6.6
Mean 3.73 5.14 3.28 8.09
LSD (5%) 0.25 as 0.93 0.78
1989/90 growing season
No legume 3.6 5.3 - 5.3
Verano stylo 4.2 5.3 1.7 7.0
Lablab (red) 3.4 5.0 3.0 8.0
Siratro 4.3 5.0 4.9 9.9
Tinaroo glycine 3.5 4.8 3.3 8.1
Mean 3.80 5.10 3.10 7.66
LSD (5%) 0.23 as 0.52 0.91
ruminant livestock during the extended dry season of six to seven months in
semi-arid central Tanzania.
Further work is needed on some aspects of soil fertility build-up and animal
feeding in order to determine the extent of improvement in productivity when
forage legumes are introduced into the crop-livestock farming systems of
semi-arid Tanzania.
Alley-cropping trial
Table 3 shows the effects of the width oiLeucaena alleys on maize grain and
stover yields and Leucaena leaf-meal production. Grain yield tended to increase
with increase in alley width, but the increases were not significant. During the
1989/90 growing season grain and stover yields were lower than in the previous
year. The lower yields could be attributed to withdrawal of fertiliser nitrogen.
219
Table 3. Effects of width ofalleys o/ Leucaena on maize grain and stover yields and Leucaena
leaf-mealproduction, 1988189 and 1989190 growing seasons
Yield (t/ha)
Maize grain (i
1988/89
lir dried)
1989/90
Maize stover (DM) Leucaena lea
1988/89
f meal (DM)
Alley width
(m) 1988/89 1989/90 1989/90
Control 4.3 2.71 6.8 4.00 - -
3 2.8 2.53 4.7 3.48 3.0 3.60
4 2.7 2.41 5.0 2.10 2.5 3.20
5 3.0 2.65 5.5 3.28 2.3 3.00
6 4.0 2.52 6.9 2.99 2.1 3.10
SE 0.55 0.30 0.62 0.34 0.37 0.39
Increases in Leucaena stubble height tended to progressively decrease
maize grain and stover yields (Table 4), but the effects were not significant. The
effects of distance of maize rows from Leucaena alleys were not clear (Table 5).
Distance from Leucaena rows Maize grain
(cm) (air dried)
Control 271
90 2.49
180 2.56
SE 0.22
Table 4. Effects ofstubble height of Leucaena rows on maize grain and stover yields, 1989190
Leucaena stubble height
(cm)
Yield (t/ha)
Maize grain
(air dried)
Maize stover
(DM)
Control
25
50
75
SE
2.71
2.66
2.48
2.44
0.26
4.00
3.06
3.10
3.39
0.30
Table 5. Effects ofdistance ofmaize rows from Leucaena on maize grain and stover yields,
1989/90
Yield (t/ha)
Maize stover
(DM)
4.00
3.16
3.21
0.24
220
These results indicate that it is feasible to introduce Leucaena into the
cropping system, using the alley-cropping approach. The additional production
(forage) from the Leucaena rows could serve to supply mulch and supplement
forage feed, particularly during the dry season.
CONCLUSIONS
Results from these two cropping studies, intercropping and alley cropping, show
that including legumes in the cropping systems in semi-arid central Tanzania can
increase the productivity of these systems. Grain as well as fodder for mulch and
livestock feed are produced with negligible or no adverse effects on grain yield.
It would be even more useful if dual-purpose legumes, such as lablab, were used.
Screening for more suitable multipurpose legumes is required to cater for fitting
legumes into the cropping systems. The total produce would then include grain
from both cereals and legumes, forage, stover and nitrogen from N-fixation.
ACKNOWLEDGEMENTS
We acknowledge the support of the International Development Research Centre
and the International Livestock Centre for Africa, through the Pasture Network
for Eastern and Southern Africa, in funding these studies. We are also grateful
for the assistance given by scientific and technical staff of the Livestock
Production Research Unit, notably R N Hero, C R Ulime and Ms T S R Mrema
for data processing and analysis, and R R Chibindu for typing the manuscript.
REFERENCES
Kusekwa M L. 1990. Pastures andforages. National agriculture and livestock research
masterplan. Ministry of Agriculture and Livestock Development, Tanzania. 27 pp.
Tothill J C. 1986. The role of legumes in farming systems of sub-Saharan Africa. In:
Haque I, Jutzi S and Neate P J H (eds), Potentials offorage legumes in farming
systems ofsub-Saharan Africa. Proceedings of a workshop held at ILCA Addis
Ababa, Ethiopia, 16-19 September 1985. ILCA (International Livestock Centre for
Africa), Addis Ababa, Ethiopia. pp. 162-185.
221
222
EFFECT OF GRAZING HOURS AND CONCENTRATE
SUPPLEMENTATION ON MILK YIELD OF CROSSBRED COWS
UNDER HIGHLAND CONDITIONS IN ARSI REGION,
ETHIOPIA
Mohammed YKurtu
Arsi Rural Development Unit (ARDU)
Animal Research Section
PO Box 388, Assela, Ethiopia
ABSTRACT
Acomparative study was undertaken on the effect of grazing time on milk yield
and general performance of lactating dairy cows. Two groups of 20 crossbred
cows were used; they were grazed on natural pasture over one calendar year
(1983-84). Cows in group I were allowed day-round grazing (less milking
hours), with a little supplementation only during the dry season. Cows in group
II were grazed in the traditional way, with about seven hours of grazing a day,
and were fed hay (1.86 kg DM/day per cow) and concentrate (0.5 kg/litre milk
yield).
Average daily herbage intake for cows in group I was 1.2 and 2.6 kg DM/
100 kg liveweight during dry and wet season, respectively. Corresponding
figures for cows in group II were 0.9 and 1.2 kg. Mean milk yield during the
year differed (P<0.05) between the two groups at 1261 and 1762 litres/cow for
groups I and II, respectively. The difference, however, varied with season, being
high in the dry season and falling to zero during wet season when pastures were
lush and green.
RESUME
Effet du temps de pdturage et d'une complementation de concentres sur la
production de lait de vaches metisses dans les hauts plateaux de la région
d'Arsi (Ethiopie)
Une etude comparative a eté effectuée sur I' effet du temps de pdturage sur la
production de lait et les performances de vaches laitieres en lactation. Deux
groupes composes chacun de 20 vaches metisses avaient 4té élevés surprairie
naturelle pendant un an (1983-1984). Les animaux du groupe I avaient accès au
223
pâturage toute la journée (à l'exception des périodes de traite) et recevaient en
outre un peu d'aliment complementaire au cours de la saison seche. Quant à
ceux du groupe II, ils étaient gérés selon la méthode traditionnelle de pâturage,
avec par jour environ sept heures de présence effective sur les parcours, et
recevaient en plus du foin (1,86 kg de matiere seche par tite) et des concentrés
(0,5 kg/litre de lait produit).
La consommation des animaux du groupe I était en moyenne de 1,2 et
2,6 kg de matiere seche par 100 kg de poids vifrespectivement au cours de la
saison seche et de I'hivernage. Les chiffres correspondants étaient de 0,9 et
1,2 kgpour les animaux du groupe U. La production moyenne annuelle de lait
des deux groupes était différente (P<0,05) et s'établissait à 1261 litres par vache
pour le groupe I contre 1762 litres pour le groupe II. Cependant, cette différence
dépendait de la saison; élevée en saison seche, elle diminuait puis s'annulait au
cours de I'hivernage, c'est-à-dire au moment où l'herbe était abondante et verte.
224
USE OF THE NYLON-BAG TECHNIQUE IN DETERMINING
THE COMPLEMENTARITY OF FEEDSTUFFS FOR DAIRY
CATTLE RATIONS
A Abate andB Kiflewahia
Department of Animal Production
University of Nairobi
PO Box 29053, Nairobi, Kenya
^ternational Development Research Centre (IDRC)
PO Box 62084, Nairobi, Kenya
ABSTRACT
Degradation of various feedstuffs (protein sources, energy concentrates and
roughages) eaten by dairy cattle in the high potential areas of Kenya was studied
by incubating samples in nylon bags in the rumens of steers. For each feedstuff,
degradation characteristics were estimated from a hand-drawn degradation curve.
Average dry-matter solubility was about 25.3, 18.0 and 24.8% for protein
feeds, energy concentrates and roughages, respectively. Maize germ flakes had
the highest degradable fraction (65.0%) and fish meal the lowest (38.5%).
Degradation rate constants averaged 0.05% per hour for protein feeds, 0.06% per
hour for energy concentrates and 0.03% per hour for roughages.
The use of degradation characteristics in evaluating livestock feedstuffs and
in formulating ration combinations for dairy cattle is discussed. The nylon-bag
technique is a useful tool for improving tropical animal production systems
because it is reliable, cheap and easy to perform.
RESUME
Etude comparee de la degradabilite de divers aliments du betailpar la
technique d incubation des sacs en nylon dans le rumen
Le rythrne de degradation de differents aliments (sources de prolines, aliments
énergetiques et)"ourrages grossiers) consommes par les bovins de race laitiere
dans les zones a forte potentialité du Kenya a eté etudie par incubation de sacs
en nylon dans le rumen des animaux. Une courbe a ete tracéepour chaque
aliment en vue de determiner ses parametres de degradabilite.
ITS
// ressort des resultant enregistres que la solubiliti moyenne de la matiere
seche etait d' environ 25,3; 18,0; et 24,8% respectivement pour les sources de
prolines, les aliments energétiques et les foutrages grassiers. Les taux de
degradation variaient de la valeur maximum de 65,0% pour la farine de germe
de mats au chiffre minimum de38,5% pour la farine de poisson. Quant a la
constante horaire de degradation, elle s'elevait a 0,05%; 0,06%; et 0,03%
respectivement pour les sources deproteines, les aliments énergétiques et les
/outrages grossiers.
L'evaluation des aliments du betail et la formulation des rations apartir
des etudes de digradabilite ont ét6 discutées. La technique du sac en nylon
constitue un instrument utile d' amélioration des systèmes d'élevage dans les
régions tropicales dans la mesure oil elle estfiable, peu chere et d'utilisation
facile.
INTRODUCTION
As a tool for studying rumen digestion, the artificial-bag technique is not new
(see, for example, Quin et al, 1938; Fina et al, 1958). In recent years the
nylon-bag technique has become more widely used, and it is now being
recommended as a means for evaluating tropical livestock feeds. However, little
work has been done on the practical application of the technique to the
evaluation of feeding systems. This study aimed to use degradation
characteristics as a means of formulating ration combinations for dairy cattle.
MATERIALS AND METHODS
Samples of various feedstuffs, used for feeding dairy cattle on small-scale farms
in different parts of Kenya, were studied. The feedstuffs included byproducts of
the food industry, pasture forage, crop residues and non-conventional feeds.
Samples were degraded in nylon bags in the rumens of three crossbred steers
(average weight 590 kg) fitted with permanent cannulae. The daily diet of the
animals comprised Napier grass and concentrate.
Feedstuffs for analysis were oven-dried at 7(J°C and then ground to pass
through a 2-mm screen. Samples (2-5 g) were measured into nylon bags
(approximately 14 x 8 cm) which were securely tied with a knot at the end of a
24-cm long string. The bag strings were permanently tied in groups of 20 to a
main string about 60 cm long, and the whole assembly was inserted into the
ventral sac of the rumen of one of the steers. All samples were incubated in
duplicate per steer and replicated in the three steers. Withdrawal of the bags was
timed to give incubation times of 1, 6, 12, 18, 24 and 36 hours for protein feeds
and energy concentrates and 1, 12, 24, 36, 48 and 72 hours for forages.
Zero-hour incubation was obtained by extrapolation of the degradation curve to
the y-axis. Retrieved bags were washed under running water until the water was
226
clear. Dry-matter degradation was determined from dry-matter determinations on
original and degraded samples.
For each feedstuff degree of dry-matter degradation was plotted against
incubation time and the curve drawn by hand (Figure 1). The values of a
(% solubility) and b (potentially degradable fraction) were determined from the
graph. The steepest section of the curve (where the change dy/dt was most rapid,
indicating maximum rate of dry-matter degradation) was identified and the
percentage degradation (p) and incubation time (t) corresponding to the mid
point of this section were read off; this enabled the degradation rate constant (c)
to be calculated from the following exponential equation (0rskov et al, 1980):
p = a + b(l-e"ct)
where:
p = dry-matter degradation (%)
a = dry-matter solubility (%)
b = potentially degradable fraction (%)
t = time of maximum rate of dry-matter degradation (hours)
c = degradation rate constant
Figure 1. Hand-dram curve for estimating % degradation (p) at time t
Degree of
degradation(%)
^ A *
1
1
1
p
1
1
/
•' 1
b
r • !
'A
a i J '
Incubatic ntime (hours)
227
The constants estimated from the hand-drawn curve were compared to those
derived using a computer program.
RESULTS AND DISCUSSION
The contents of major nutrients in the feeds (Table 1) were within the published
range (Said, 1971; Abate, 1980; Kamande, 1988) except that the level of
insoluble material in the fish meal was very high, probably because of a high
proportion of scale and contamination in the sample analysed.
The degradation characteristics (Table 2) are generally comparable to those
obtained for similar feeds by other authors (0rskov et al, 1980; Kamande, 1988).
Previous studies used sinkers of sand or water (Kamande, 1988) or nylon tubes,
or weights to position bags in the rumen (0rskov et al, 1980), but the present
study indicates that reliable, accurate, results can be obtained without these aids.
There is, however, some variation in estimates of solubility. For example,
compared with the values found in this study, Kamande (1988) reported a higher
solubility value for wheat bran and a lower solubility for lucerne. This may
suggest that solubility is unreliable as an indicator of feeding value.
Content (%DM)
DM Crude Crude Neutral
Feed (%) Ash protein fibre detergent fibre
Protein sources
Fish meal 96.4 15.6 35.0 nd nd
Soybeans 90.9 4.9 40.8 9.1 nd
Cottonseed cake 97.3 5.9 31.1 20.7 nd
Sunflowerseed cake 96.5 5.7 33.6 28.8 nd
Lucerne, flowering 91.8 10.4 22.7 nd 77.8
Energy concentrates
Maize germ flakes 87.8 6.0 16.5 11.4 nd
Wheat bran 91.2 7.9 17.2 13.4 nd
Cornflakes waste 91.4 2.7 8.1 9.3 nd
Green banana fruit 92.5 6.1 5.0 6.4 nd
Roughages
Bean stalks and pods 90.7 8.7 6.3 nd 70.8
Coffee pulp 89.9 10.7 13.6 nd 51.5
Hay (mixed species) 92.0 8.7 8.8 nd 76.6
Kikuyu grass 93.5 126 19.0 nd 64.8
Table 1. Dry-matter, ash, crude-protein andfibre contents offeedstuffs
nd = value not determined
228
Table 2. Degradation characteristics offeedstuffs obtainedfrom a hand-drawn curve and by
computer
a b c
Feed Hand Computer Hand Computer Hand Computer
Protein sources
Fish meal 15.3 13.9 38.5 43.1 0.054 0.066
Soybeans 34.9 34.8 626 66.5 0.053 0.078
Cottonseed cake 21.8 14.6 45.6 47.8 0.057 0.220
Sunflowerseed cake 22.5 21.7 41.4 46.3 0.054 0.069
Lucerne, flowering 32.1 30.3 47.6 48.0 0.050 0.074
Energy concentrates
Maize germ flakes 10.2 11.9 65.0 61.8 0.047 0.086
Wheat bran 14.4 12.7 55.2 56.6 0.072 0.128
Cornflakes waste 28.8 30.3 51.4 56.5 0.063 0.067
Green banana fruit 18.4 17.5 53.6 169.4 0.044 0.012
Roughages
Bean stalks and pods 15.0 12.6 45.9 52.7 0.033 0.041
Coffee pulp 42.8 41.3 48.4 54.9 0.035 0.037
Hay (mixed species) 16.4 15.3 41.8 48.2 0.029 0.033
Kikuyu grass 25.2 229 55.3 62.2 0.037 0.043
p = a + rXl-e"**)
where:
p = dry-matter degradation (%)
a = dry-matter solubility (%)
b = potentially degradable fraction (%)
t = time of maximum rate of dry-matter degradation (hours)
c = degradation rate constant
Degradation characteristics derived by computer are also given in Table 2.
There was a high correlation (r = 0.97) between the solubility estimates obtained
by the two methods, indicating that both methods are equally applicable for
determining this parameter. However, there was little or poor agreement between
the methods in the estimation of b (r = 0.32) and c (r = 0.60); on average the b
and c values were higher than those obtained from the hand-drawn curve. It is
therefore difficult to judge the reliability of either method, but comparison of
results from this study with those reported in the literature suggests that the
estimates made from the hand-drawn curve are more accurate.
All the protein sources showed similar rates of degradation. However, this
similarity can be misleading. The relatively low total degradability (potentially
degradable fraction) of the fish meal implies that this feed could be a source of
undegradable protein and therefore would be useful for cows that are high
producers of milk. In contrast soybean was so highly degraded that more of its
229
protein would be exposed to hydrolysis, and so diets based on this feedstuff
would need to be supplemented by a source of rumen degradable energy, such as
cornflakes waste or possibly wheat bran (but not coffee pulp which, despite a
high total degradability, has a low degradation rate).
The low solubility of the bean stalks and pods and hay is in agreement with
similar values demonstrated for Kenyan pasture grasses and fodder legumes
(Kamande 1988) and low quality range forage (Rutagwenda, 1989). More
recently Abate (1990) has shown that maize forage harvested and ensiled at
different stages of growth differed in solubility and degradability. Fibrous
materials are less soluble because of the dominance of structural over soluble
carbohydrates in the cell wall. Also, Van Soest (1982) has demonstrated that
degree of lignification has a negative effect on cell wall digestion in forages. The
low solubility of fish meal, compared with cottonseed and sunQowerseed cakes,
may be a result of the composition of the meal or of contamination with
indigestible matter. Low and slow degradability, as found in the hay, can limit
voluntary intake of feed. It is hence desirable that roughages such as hay or crop
residues be combined with highly soluble feedstuffs; such a combination would
stimulate a more active rumen microbial population which would degrade the
fibre faster and hence increase digesta passage rate and DM intake.
CONCLUSIONS
Knowledge of dry-matter degradation characteristics of feedstuffs can be used as
a basis for formulating ration combinations for dairy cattle in tropical animal
production systems. The nylon-bag technique offers a cheap, reliable and easy to
perform method of obtaining this information; analysis can be done by hand
without the need for expensive computer equipment and software. However,
assessment of protein degradability of feedstuffs is also desirable, to ensure that
protein requirements are met.
ACKNOWLEDGEMENTS
We are grateful to the Head and staff of the Animal Production Research
Programme at the Kenya Agricultural Research Institute (KARI), Muguga,
where this study was carried out.
REFERENCES
Abate A 1980. In vitro estimation of the energy content of some feeds commonly fed to
livestock in Kenya. EastAfrican Agricultural and Forestry Journal 45:255-260.
Abate AN. 1990. Nutritive value ofmaizeforage silage fed to dairy cowsfor an
integrated system ofgrain and milkproduction in Kenya. PhD Thesis. University of
Aberdeen, Aberdeen, UK 199 pp.
230
Fina L R, Teresa G W and Bartley E E. 1958. An artificial rumen technique for studying
rumen digestion in vivo. Journal ofAnimal Science 17:667.
Kamande G M. 1988. Forage and concentrate protein utilization by dairy cattle. MSc
Thesis. University of British Columbia, Vancouver, BC, Canada. 113 pp.
0rskov E R, Hovell F D DeB and Mould F. 1980. The use of the nylon bag technique for
the evaluation of feedstuffs. TropicalAnimal Production 5:195-213.
Quin J I, Van Der Wath J G and Hyburth S. 1938. Studies on the alimentary canal of
Merino sheep in South Africa. 4. Description of experimental technique.
Onderstepoort Journal of Veterinary Science andAnimal Industry 11 :341.
Rutagwenda T. 1989. Adaptation ofsheep and goats to seasonal changes offorage on a
semi-arid thombush savannah pasture in northern Kenya. PhD Dissertation.
Tierarztliche Hochschukle, Hanover, FR Germany. 131 pp.
Said AN. 1971. In vivo digestibility and nutritive value of Kikuyu grass (P. clandestinum)
with a tentative assessment of its yield of nutrients. Exist African Agricultural and
ForestryJournal 37:15.
Van Soest P J. 1982. Nutritional ecology ofthe ruminant. O&B Books, Corvallis, Oregon,
USA. 374 pp.
231
232
CROP RESIDUES AND AGRO-INDUSTRIALBYPRODUCTS IN
ZAMBIA: AVADLABILITY, UTILISATIONAND POTENTIAL
VALUE IN RUMINANT NUTRITION
EMAregheore andAM Chimwano
Department of Animal Science
School of Agricultural Sciences
University of Zambia
PO Box 32379, Lusaka, Zambia
Permanent address:
College of Education
PMB 1251, Warn, Bendel State, Nigeria
ABSTRACT
Large quantities of crop residues and agro-industrial byproducts are produced
each year in Zambia. The potential value of these materials in animal nutrition is
well known, but little information has been published on their actual utilisation
as livestock feed or on their availability to smallholder farmers in the country.
Where they are available, most of them are used haphazardly because farmers
lack storage facilities and knowledge of how to use them effectively in animal
diets. Efforts currently being made to help smallholders solve their animal feed
problems are focusing on improving methods of harvesting, handling and
processing crop residues and byproducts, and on incorporating them into
year-round feed budgets. Improved feeding methods could lead to substantial
increases in Zambia's livestock population.
RESUME
Les re~sidus de ricolte et les sous-produits agro-industriels en Zambie:
production, utilisation et valeur potentielle pour I'alimentation des ruminants
De grandes quantités de residus de recolte et de sous-produits agro-industriels
sontproduits chaque année en Zambie. Alors que leur valeurpotentielle en tant
qu'aliment du betail est bien documentée, on nepeat en revanchepas en dire
autant de leur utilisation reelle et de leur relative disponibilité au niveau des
233
petits paysans. Ceux-ci les utilisent au petit bonheur, faute de materiel de
conservation ex d'une methode rationnelle a" introduction de cesproduits dans
I'alimentation du betail. Aussi les efforts deployes actuellement en Zambie pour
aider les petits éleveurs a mieux nourrir leurs animaux visent-us en priority non
seulement a améliorer leurs methodes de récolte et de traitement des residus de
recolte et des sous-produits agro-industriels, mais egalement a les amener a
prévoir dans leurs budgets les dipenses annuelles d' achat de ces produits.
L amelioration des methodes d'alimentation du betail devrait permettre
d'accroitre de maniere substantiale les effectifs des animaux d'élevage dans le
pays.
INTRODUCTION
Zambia's ruminant livestock population currently comprises about 2.4 million
cattle, more than 600 000 goats and more than 50 000 sheep. Malnutrition is the
major constraint on animal production, especially during the seven-month dry
period when grazing ruminants lose weight dramatically. However, Zambia
produces sufficient feed resources, in the form of crop residues and agro-
industrial byproducts, to make it potentially capable of supporting a much larger
animal population. The problem is that these resources may not be readily
available to smallholder farmers, or are not being used as effectively as they
could be. This paper discusses the availability, utilisation and potential value in
ruminant nutrition of agro-industrial byproducts and crop residues in Zambia.
CROP RESIDUES ANDAGRO-INDUSTRIALBYPRODUCTS IN
ZAMBIA
Production
Zambia produces a wide variety of cereals and other food crops (Table 1). After
these crops have been harvested and processed, various residues and byproducts
remain—for example, stovers, straws, husks, cobs and brans from cereal crops;
and shells, heads, pulp, peels and tops from other crops.
No accurate data have been published on the quantities of crop residues and
agro-industrial byproducts produced in Zambia. However, based on government
crop production statistics, and using appropriate crop:residue ratios (Munthali
and Dzowela, 1987), it is estimated that more than 3.25 million tonnes of crop
residues and byproducts could be available each year (Tables 2 and 3).
Value in livestock nutrition
Basic chemical composition and nutritive value data available for most of the
crop residues and agro-industrial byproducts produced in Zambia (Chimwano,
234
Table 1. Provincial distribution ofcrops in Zambia
Province Crops
Central
Copperbelt
Eastern
Luapula
Lusaka
Northern
Northwestern
Southern
Western
Maize, sweet potato, soybean, groundnut, cotton, watermelon, sunflower,
wheat, tobacco
Maize, sunflower, soybean, beans, groundnut, wheat, oilseeds
Maize, soybean, sunflower, orange, sweet potato, cassava, cotton, groundnut,
pigeon pea, sorghum
Cassava, rice, maize, sunflower, sweet potato, millet, beans, banana, groundnut,
oilseeds
Maize, soybean, sunflower, sorghum, tobacco, sweet potato, pigeon pea, rice,
cotton, wheat, watermelon, orange
Rice, maize, cassava, sunflower, millet, sweet potatoe, banana, cotton, beans,
soybean, coffee
Maize, pineapple, sweet potato, soybean, sunflower, millet, orange, cassava,
faba bean, sorghum, coffee, groundnut, rice
Maize, soybean, sunflower, tobacco, sugarcane, cotton, banana, millet, oranges
Maize, sorghum, rice, millet, groundnut, faba bean, cassava
Table 2. Annualproduction ofcrop residues
Annual production (thousands of tonnes)
Province
Soy/
Maize Sorghum Millet Rice Wheat Groundnut sweetbean Sunflower
stover stover stover straw straw straw straw heads
Central 586.7 11 1.4 - 1.8 1.4 2.4 8.1
Copperbelt 72.7 18 - 0.1 1.5 0.7 0.8 0.1
Eastern 641.5 9 0.5 1.4 - 9.1 1.0 7.5
Luapula 2Z9 0.5 0.1 0.7 - 0.4 0.4 0.1
Lusaka 119.5 6 - - 5.9 0.4 5.2 1.6
Northern 182.5 0.5 8 5.2 - 1.6 4.6 0.1
Northwestern 20.5 7.2 1.2 0.8 - 0.3 4.7 0.1
Southern 536.0 20.1 0.5 - 1.8 3.8 3.7 7.6
Western 40.8 17.1 11.7 3 - 0.4 - -
Total 2223.1 90.0 23.4 11.2 11.0 18.1 22.8 25.2
Based on government crop production statistics and stover to grain ratios of 2: 1 for maize, sorghum and
millet; and straw to grain ratios of 1:1 for rice, wheat, groundnut and soybean (Munthali and Dzowela,
1987)
1990) show clearly that they could satisfy the nutritional requirements of
ruminant livestock.
235
Table 3. Annual production of agro-industrial byproducts
Annua1 production (thousands of tonnes)
Soybean Cottonseed Sunflower
Province Maize bran Rice bran Wheat bran cake cake cake
Central 94.6 - 0.3 1.2 77.4 2.5
Copperbelt 11.7 0.1 0.4 0.3 0.8 -
Eastern 103.5 0.1 - 0.2 50.7 2.3
Luapula 3.7 0.7 - - 0.2 -
Lusaka 193 - 1.4 2.4 29.1 0.5
Northern 29.4 0.5 - 0.2 0.4 -
Northwestern 3.3 0.1 - 0.1 0.1 -
Southern 86.5 - 0.5 1.8 233.3 2.3
Western 6.6 0.3 - - 2.1 -
Total 358.6 1.8 25 6.2 484.1 7.6
Based on government crop production statistics and grain to bran/cake ratios of 3. 1 : 1 for maize; 10: 1 for
rice; 4:1 for wheat; 2:1 for groundnut; and 3.3:1 for cottonseed (Munthali and Dzowela, 1987)
Many of these materials have been studied in detail. For example, orange
pulp and peels, byproducts of the citrus industry, are known to be good sources
of energy for cattle, small ruminants and even monogastrics (Ammerman et al,
1963; Devendra, 1973). Peels, hulls and pulp of other crops, such as cassava,
groundnut, sunflower, soybean, potato, pineapple, banana and watermelon, have
also been shown to be of value in livestock nutrition (Ting and Deszyck, 1961;
Bhattacharya and Harb, 1973; Devendra, 1973; Cantner, 1987; Balock et al,
1988). Malt screening, brewers' grains and Chibuku (local brew) wastes, tonnes
of which are produced annually by Zambia's two breweries (at Lusaka and
Ndola), are high in protein and of medium energy, and their value in livestock
nutrition is well documented (Adebowale and Ademosun, 1981; Ugye et al,
1988; Aregheore et al, 1990). The use of molasses as a carbohydrate and an
energy source has been extensively studied (Reyley, 1961; Shindende, 1990).
And milling byproducts such as bran, wheatlings and screenings are important
byproducts which, along with oilseed cakes from soybean, groundnut, cotton and
sunflower, could form important raw materials in the production of livestock
feed in Zambia.
UTILISATION OF CROP RESIDUES AND AGRO-EVDUSTRIAL
BYPRODUCTS
Little information is available on the extent to which smallholder farmers in
Zambia use crop residues and agro-industrial byproducts as livestock feed. It is
236
very likely, however, that these resources are under-utilised. Even when they are
utilised, farmers may not be able to incorporate them effectively into their
year-round livestock feeding programmes because they lack suitable storage
facilities and technical knowhow on treatment and processing methods and on
formulating feed rations.
The few crop residues known to be used for livestock nutrition in Zambia
are brans, stovers and straws of wheat, maize, sorghum and millet. But these are
not used in the most efficient manner; smallholder farmers usually feed them to
their stock in situ during harvest seasons.
Most of the valuable agro-industrial byproducts produced in Zambia are not
used for livestock production at all, and are simply wasted. The problem is
mainly one of availability; food manufacturing and processing industries are
generally located in urban centres along the railway lines, and so their
byproducts are not readily available to smallholder farmers in the rural areas of
the country.
IMPROVING LIVESTOCK PRODUCTION IN ZAMBIA
Ruminant livestock production in Zambia could be increased substantially if
more efficient feeding methods could be introduced. Adequate feed resources are
potentially available, and so the challenge before animal nutritionists is how to
improve their utilisation and hence help smallholder farmers solve their feed
problems. Current research is focusing on:
• improving methods of harvesting, handling and storing crop residues so as
to reduce wastage
developing treatment methods that could increase the availability of
nutrients
• introducing supplementation techniques to correct nutrient deficiencies
• determining seasonal availability and nutritional values of residues and
byproducts with a view to formulating adequate year- round feeding systems
REFERENCES
AdebowaleEAand Ademosun AA 1981 . The carcass characteristics and chemical
composition of organs and muscles of sheep and goats fed brewers' dried grains-based
ration. TropicalAnimalProduction 6:133-137.
Ammerman C B, Arrington L R, McCall J T, Wing J E and Davis G K. 1963. Nutritive
value of dried citrus pulp for steers. Journal ofAnimal Science 20:398 (Abstract).
Balock G M, Soomro F M, Isani G B and Carpenter J R. 1988. Utilization of banana plant
silage as a source of roughage for dairy cows. Journal ofDairy Science 71 (suppl 1):
132 (Abstract).
Bhattacharya AN and Harb M. 1973. Dried citrus pulp as a grain replacement for Awasi
lambs. Journal ofAnimal Science 36: 1175-1180.
237
Cantner E W. 1987. The utilization of agricultural waste products in animal nutrition.
AnimalResearch and Development 26:56-70.
Cbimwano AM. 1990. Zambia'sfarm livestockfeedstuffs: Their nutrient content and
nutritive value. University of Zambia, Lusaka, Zambia. 12 pp.
Devendra C. 1973. Effect of level of inclusion of citrus meal on the digestibility of
concentrate diet for sheep in Trinidad. TropicalAgriculture (Trinidad) 50:221-224.
Munthali J T and Dzowela B H. 1987. Inventory of livestock feeds in Malawi. In:
Kategile J A, Said AN and Dzowela B H (eds), Animalfeed resourcesfor small-scale
livestockproducers. Proceedings of the second PANESAworkshop, held in Nairobi,
Kenya, 11-15 November 1985. IDRC-MR165e. IDRC (International Development
Research Centre), Nairobi, Kenya, pp. 61-69.
Reyley H B. 1961. Urea-molasses supplementation in dairy cattle. Journal ofAnimal
Nutrition 6:71-52.
Shindende D. 1990. Intake and response ofgrazing goats to supplements ofurea-
molasses blocks containing varying amount of cement. Special project report,
Department of Animal Science, University of Zambia, Lusaka, Zambia. 19 pp.
Ting S V and Deszyck E J. 1961. The carbohydrates in the peel of oranges and
grapefruits. Journal ofFood Science 26:146-152.
Ugye B H, Anugwa F I O and Nwosu C C. 1988. Effects of varying levels of dietary dried
brewers' grains on performance and carcass characteristics of growing pigs. Bulletin
ofAnimalHealth andProduction in Africa 36:3137.
238
EFFECT OF LEGUME CROP RESIDUES AND CONCENTRATE
SUPPLEMENTATION ON VOLUNTARY INTAKEAND
PERFORMANCE OF KIRDI SHEEP FED ABASALDIET OF
RICE STRAW
A TNgwa andCL Tawah
•Institute of Animal Research (IRZ)
PO Box 12, Yagoua, Cameroon
Institute of Animal Research (IRZ)
PO Box 65, Ngaoundere, Cameroon
ABSTRACT
Twenty young Kirdi rams of the West African Dwarf sheep, averaging 22 kg
liveweight and 15 months of age, were randomly assigned to four feeding groups
and subjected to an eight-week feeding trial, to determine the effect of different
protein supplements on voluntary intake of rice straw and on performance.
Control group animals were fed a daily basal diet of ad libitum rice straw and
250 g of rice bran. Other groups were fed the basal diet supplemented with 300 g
of groundnut haulms, 45 g of cottonseed cake or 210 g of chopped cowpea vines.
Liveweight changes of the supplemented groups did not differ significantly but
there was a difference (P<0.05) in liveweight gain between the supplemented
groups and the control group. There were highly significant (P<0.01) differences
between the groups in the intake of rice straw; cottonseed cake increased intake
while the crop residues reduced intake. Variations in height at withers, heart girth
and scapulo-ischial length showed no significant differences between treatments.
Cottonseed cake was the most effective supplement, in terms of both liveweight
gain and intake of rice straw. However, because crop residues are readily
available to farmers, it is worthwhile paying some attention to them.
RESUME
Effet de la complementation de la paille de riz avec des résidus de culture de
légumineuse et des concelitris sur I 'ingestion volontaire d 'ovins Kirdi
Un essai d'alimentation d'une durée de huit semaines a ete effectuépour
determiner I' effet de divers compléments protéiques sur les performances et
239
I'ingestion volontaire depaille de riz chez des ovins. 20 jeunes beliers Kirdi de
race Djallonke, pesant en moyenne 22 kg et ages d'environ 15 mois ont ete
divises au hasard en quatre groupes soumis chacun a un régime alimentaire
donne. Tous les animaux recevaient de la paille de riz ad libitum comme aliment
de base; ceux du lot temoin recevaient en outre 250 g de son de riz par jour et
par tite, alors que ceux des trois autres lots recevaient soit 300 g de fanes
d'arachiae, soit 45 gde tourteau de coton, soit 210 g de fourrage de niibé
broyé. Les variations depoids des animaux recevant une complémentation
n'étaientpas significativement differentes de celles du lot témoin mais leurs
gains depoids vifétaient significativement (P<0,05) différents. L' ingestion de
paille de riz variait significativement (P<0,01) selon la ration: elle etait élevee
avec le tourteau de coton et faible avec les résidus de recolte. En revanche, les
variations des mensurations lineaires (hauteur au garrot, perimetre thoracique
et longueur scapulo-ischiale) n'étaientpas significativement différentes. Bien
que le tourteau de coton donne les meilleurs résultats en ce qui concerne les
gains depoids et I' ingestion depaille, on ne saurait cependant déconseiller
I'utilisation des résidus de recolte, étant donne que les paysans peuvent se les
procurer facilement.
INTRODUCTION
Thousands of tonnes of rice straw are destroyed every year in the Far North
Province of Cameroon. This is a waste of resources: even with a crude-protein
content of only 4% (Nour, 1986; Udo and El-Harith, 1985) and an organic-matter
digestibility of between 40 and 50% (Pearce, 1984; Zainur et al, 1984), rice
straw could be a major feed for ruminants if properly supplemented. Intake of
rice straw is limited to less than 2% of body weight (Jackson, 1978) because of
the slow rate at which it is fermented in the rumen, but it can still be a major
source of energy for ruminants in an area like the Far North Province where
pasture and grain production is hampered by a long (eight-month) dry season.
Chemical, physical or microbial methods of treating straws to improve their
low energy and protein content (Hartley, 1981; Kiangi et al, 1981; Saadullah et
at, 1981; Wongsrikeao and Wanapat, 1984; Mason and Owen, 1986) are of little
economic relevance to small-scale farmers. However, it is at this level that the
problem of weight loss by animals during the dry season is most critical. There is
thus a great need to prevent weight loss by the use of simple techniques
applicable to farmers and involving readily available agro-industrial byproducts
and crop residues. Supplementation of poor quality roughages, including cereal
crop residues, with legumes has been shown to increase their digestibility
(Devendra, 1982) or intake (Mosi and Butterworth, 1985) or both (Minson and
Milford, 1967; Lane, 1982; Moran et al, 1983; McMeniman et al, 1988).
This study investigated the effects of different protein supplements on the
intake of rice (Oryza sativa) straw, on the efficiency of nutrient utilisation and on
the performance of Kirdi rams.
240
MATERIALS AND METHODS
Animals
Twenty Kirdi yearling male lambs (average age 15 months; average liveweight
22 kg) were randomly assigned to four treatment groups of five animals each.
The animals were kept in a roofed half-walled shed with a concrete floor. They
were treated against worms and ectoparasites and fed polyvitamins dissolved in
water.
Feeds and feeding
A two-week adaptation period on a daily diet of ad libitum rice straw and 250 g
rice bran per animal was followed by an eight-week experimental period, during
which the groups were allocated to one of four diets:
• basal diet (control): rice straw (ad libitum, 125% of daily intake) plus 250 g
rice bran per animal per day
• diet 1: basal diet plus 300 g groundnut haulms per animal per day
• diet 2: basal diet plus 45 g cottonseed cake per animal per day
• diet 3: basal diet plus 210 g chopped cowpea vines per animal per day
The experimental period was divided into four periods of two weeks each to
examine the effect of time of feeding on voluntary intake and performance.
Table 1 shows the nutrient composition of the ration ingredients. The rations
were formulated to be approximately isonitrogenous. Diets 1 and 3, unlike diet 2,
were isocaloric. The protein supplements were offered each morning before the
basal diet. Water and a 50:50 common salt/bonemeal mineral supplement were
offered ad libitum. The feed ingredients and refusals were weighed each morning.
Dry matter
(%)
Energy*
(UF/kgDM)
Digestible
crude protein Calcium
(%DM)
Phosphorus
Ingredients (%DM) (%DM)
Rice straw 95 0.42 0 0.19 0.08
Rice bran 94 0.85 0.9 0.16 1.74
Cottonseed
cake (Alibet)
95 0.84 383 0.24 1.24
Groundnut
haulms
94 0.43 5.8 1.41 0.21
Cowpea vines 94 0.60 9.2 0.64 0.29
Table 1. Nutrient composition ofration ingredients
' UF = unite fourragere = 1883 calories
Dry-matter content was determined on-station. Other analyses were carried out by the nutrition
laboratory of the Institut cf elevage et de medecine veterinaire des pays tropicaux (IEMVT) in France
241
Animals were weighed every two weeks during the experimental period.
Height at withers, heart girth and scapulo-ischial length were measured at the
beginning, middle and end of the experiment.
Statistical analysis
Liveweight changes, average daily gains and feed intake were subjected to
analysis of variance (Steel and Torrie, 1980). The treatment means were
compared using Duncan's new multiple range and Student's test (Ott, 1977).
RESULTS
All animals remained in good health throughout the experimental period.
The voluntary intake of rice straw varied highly significantly between
feeding groups and with time of measurement (Table 2). Rice straw intake
increased highly significantly (P<0.01) in animals supplemented with cottonseed
cake but decreased highly significantly in animals supplemented with the legume
crop residues (Table 3).
The liveweight changes of the supplemented animals did not differ
significantly from each other (Table 2) although they were highly significantly
affected by the time of measurement. Average daily gain tended to be affected by
the type of protein supplementation (Table 2). This tendency may reflect the
Table 2. Least-squares analysis ofvariance ofmean squares office straw intake, liveweight
change and average daily gain
Source of variation df Mean square Significance level
Rice straw intake
Treatments (T) 3 7.123 P<0.01
Supplementation period (P) 3 0.432 P<0.01
TxP 9 0.206 P<0.05
Residual 192 0.060
Liveweight change
Treatments (T) 3 0.897 M
Supplementation period (P) 3 9.162 P<0.01
TxP 9 0.410 ns
Residual 64 0.449
Average daily gain
Treatments 3 1144.58 P<0.1
Residual 16 467.60
242
502 380 552 446
736 896 829 877
77.1 93.8 86.8 86.2
0.41 0.48 0.47 0.51
20.8 37.2 37.2 39.0
50.7 77.5 79.2 76.5
36.8 18.3 15.9 17.8
13.4 19.2 15.6 17.8
670.0 392.6 291.5 361.1
Table 3. Efficiency offeed utilisation and cost ofration for Kirdi sheep by treatment group
Parameters Basal diet Diet 1 Diet 2 Diet 3
Dry matter intake
Rice straw (g/animal per day)
Total (g/animal per day)
Total (g/kg liveweight0'75)
Energy intake (UF/animal per day)'
Digestible crude protein intake (g/animal
per day)
Protein:energy ratio (g/UF)*
Feed utilisation efficiency (kg DM
consumed/kg liveweight gain)
Cost of daily ration/animal (FCFA)
Cost per kg liveweight gain/day (FCFA)
* UF = unite fourragere = 1883 calories
Basal diet = ad libitum rice straw plus rice bran (250 g/animal per day)
Diet 1 = basal diet plus groundnut haulms (300 g/animal per day)
Diet 2 = basal diet plus cottonseed cake (45 g/animal per day)
Diet 3 = basal diet plus chopped cowpea vines (210 g/animal per day)
short duration (eight weeks) of the experiment. However, the objective of the
study was to maintain the weight of the animals during the period of scarcity
which, evidently, was achieved. The average daily gain of the supplemented
groups exceeded (P<0.05) that of the control group.
Cottonseed cake was the most effective protein supplement in terms of both
intake and weight gain (Tables 3 and 4). In the supplemented groups, the
quantity of protein offered was similar, suggesting that the intake of rice straw
was influenced by the source of protein supplement. The high proteimenergy
ratios (Table 3) are explained by the poor quality of rice straw which was the
major source of energy in the diets. Height at withers, heart girth and scapulo-
ischial length did not differ significantly with the treatments (Table 4) although
there was a general increase in the supplemented groups. Within the same
treatment group, variations in heart girth and scapulo-ischial length were greater
than the variation in height at withers.
DISCUSSION
The dry-matter intakes of rice straw observed for sheep fed the different diets
were comparable to the values of 0.3-0.5 kg/animal per day reported by other
authors (Zainur et al, 1984; Boonloom and Poukanond, 1984) under similar
experimental conditions. They were, however, lower than values reported for
chemically treated straws: chemical treatment of straws increases their
243
Table 4. Weight gain and linear measurements o/Kirdi sheep by treatment group
Zootechnical parameters Basal diet Diet 1 Diet 2 Diet 3 SD
Number of animals 5 5 5 5
Average initial weight (kg) 22.26 2258 22.54 24.04
Average final weight (kg) 23.38 25.32 25.46 26.80
Average daily weight gain
(g/day)
20.00 48.93 5214 49.29 9.67
Average change in height at
withers (cm)
1.33 1.00 1.80 1.70 0.30
Average change in heart girth
(cm)
2.30 3.10 3.50 200 0.40
Average change in
2.60 3.10 3.00 250 0.50
scapulo-ischial length (cm)
Basal diet = ad libitum rice straw plus rice bran (250 g/animal per day)
Diet 1 = basal diet plus groundnut haulms (300 g/animal per day)
Diet 2 = basal diet plus cottonseed cake (45 g/animal per day)
Diet 3 = basal diet plus chopped cowpea vines (210 g/animal per day)
digestibility and intake (Ibrahim, 1984). Rice straw, like any other crop residue,
has a high crude-fibre content of 40% (Suriyajantratong and Wilaipon, 1984) and
low levels of protein, soluble carbohydrates and minerals. It has also been
reported that the ash fraction of rice straw contains mostly silica which not only
has no nutritional value for animals but also depresses the digestibility of other
nutrients (Clawson and Garett, 1970). It is thus likely that the high fibre and ash
contents of rice straw are the major factors limiting its utilisation by ruminants.
Intake and digestibility of rice straw are consequently too low to sustain animal
maintenance, let alone support animal production. Supplementation with energy
and/or protein should thus increase the efficiency of utilisation of rice straw.
Supplementation with groundnut haulms, cowpea vines and cottonseed cake
produced positive effects on growth rate. However, intake of the basal diet
decreased when supplemented with legume crop residues. An ideal supplement
should maintain or increase the intake of the basal diet rather than substitute for
it, a phenomenon often seen with animals fed legumes (Moran et al, 1983) or
legume crop residues (Mosi and Butterworth, 1983). Supplementation with
legume crop residues contributes fermentable energy to the rumen in the form of
available cellulose and hemicellulose which stimulate fibre digestion (Silva and
0rskov, 1985). It is possible that offering such material prior to the daily feeding
of rice straw may induce a greater degree of colonisation of rice straw by rumen
bacteria and by rumen fungi, which have been implicated in the breakdown of
fibre (Bauchop, 1981). 0rskov and Dolberg (1984) stated that if animals feeding
on untreated straws or poor quality roughages are supplemented with substrates
which increase the fermentation rate of cellulose, the rumen environment
becomes similar to that of animals receiving ammonia-treated straws. This may
244
explain why Nolan and Stachiw (1979) found an increase in the intake of wheat
straw by sheep when 50 g of lucerne chaff was added to their ration.
The improvement of the rumen environment when animals are fed untreated
straws or poor quality roughages with certain supplements is very important in
areas where chemical treatment of these poor roughages is not possible. The
supplement should be an easily digestible byproduct containing cellulose and/or
hemicellulose (0rskov and Dolberg, 1984), such as green grass, azolla, water
hyazinth, legumes or citrus pulps. The higher intake of rice straw by sheep
supplemented with cottonseed cake is explained by the fact that cottonseed cake
not only provided the essential nutrients to maintain optimal rumen activity but
was also more rapidly degraded in the rumen. Groundnut haulms and cowpea
vines, although contributing the essential nutrients, took much longer to break
down, hence the lower intakes of the basal diet. Ingested fibre material must be
broken down by rumination, microbial fermentation or both to produce particles
which are small enough to pass through the reticulo-omasal orifice (Blaxter et al,
1956; Crampton, 1957; Campling and Balch, 1961; Campling et al, 1962).
Cottonseed cake turned out to be the most efficient supplement, probably
because animals fed this supplement had more than twice the quantity of energy
received by the other treatment groups. This is attributed to the higher intake of
rice straw by this group (Table 3). The cottonseed cake supplemented diet was
the cheapest (Table 4). However, as groundnut haulms and cowpea vines are
more readily available to farmers, it is worth paying particular attention to them.
CONCLUSIONS
The use of low quality roughages in ruminant diets is limited, at least in part, by
the insufficient intakes of these roughages to ensure satisfactory animal
performance. It has been suggested that the intake of these roughages is limited
mainly by their low digestibilities. This study shows that giving small quantities
(up to 30% of total DM intake) of a legume crop residue will substantially
increase the total DM intake and improve the digestibility of rice straw above
that which can be obtained by use of non-protein-nitrogen supplements.
Judicious amounts of legume crop residues, which are generally available in
abundance during the harvest season, could be fed in combination with rice
straw and rice bran to small ruminants in the hot dry season to ensure minimal
weight loss, mortality and weakness due to malnutrition.
ACKNOWLEDGEMENTS
We wish to thank the Institute of Animal Research, Yagoua Station, for providing
the facilities for this work; Mr E L Bengolo, who helped in the planning and
execution of this experiment; Messrs S Patcha and D Dimati for their care and
feeding of the experimental animals; and Mrs I Mairama for typing this paper.
245
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248
THE POTENTIALOF RUSSIAN COMFREY (SYMPHYTUM
OFFICINALE) ASANANIMALFEEDSTUFF IN UGANDA
FB Bareeba, WO Odwongo andJ S Mugerwa
Department of Animal Science
Faculty of Agriculture and Forestry
Makerere University
PO Box 7062, Kampala, Uganda
ABSTRACT
Atrial was established at the Makerere University farm, Kabanyolo, Uganda, to
study the growth characteristics, dry-matter yield and nutrient composition of
Russian comfrey (Symphytum officinale) to assess its potential for livestock
feeding in Uganda.
Dry-matter (DM) yields increased from about 2 t/ha at eight weeks of
growth to 3 t/ha at 12 weeks of growth. Yields of 2-3 t DM/ha were sustained
during four, five and six weeks of regrowth. Crude-protein (CP) production
increased steadily from 344 kg/ha at eight weeks to 517 kg/ha at 12 weeks of
growth. However, CP content remained constant at about 16% at all cuttings.
This is comparable to CP values of good to medium quality forage legumes, but
is higher than observed in most pasture grasses. Both macro- and micro-mineral
contents of the plants were higher at all cuttings than normally observed in most
Ugandan fodder plants. Amino acid analyses indicated that the protein quality of
comfrey is comparable to that of good quality alfalfa leaf meal, but higher than
that oiAmaranthus leaf meal.
Russian comfrey thus has potential as a complement to forage legumes,
grasses and crop residues for sustainable animal production in Uganda.
RESUME
Evaluation de la consoude voyageuse (Symphytum officinale) en vue de
I'alimentation du be"tail en OUganda
Un essai a eté realisé a laferme expérimentale de I' UniversityMakerere a
Kabanyolo (Ouganda) pour etudier la croissance, la production de matiere
seche et la teneur en Elements nutritifs de la consoude voyageuse (Symphytum
officinale) en vue de son introduction dans I'alimentation du betail en Ouganda,
249
Laproduction de matiere seche, qui etait d'environ 2 t/ha a 8 semaines,
passait a 3 t/ha a 12 semaines puis allait del a 3 t/ha apres 4,5et6 semaines
de repousse. Quant a la production de proteines brutes, elle augmentait
regulierement de 344 kg/ha a 8 semaines a 517 kg/ha a 12 semaines. Toutefois,
la teneur enproteines brutes demeurait constante, s'etablissant toujours autour
de 16%. Ce taux est comparable a ceux enregistrés pour les légumineuses
fourrageres de bonne qualite ou de qualite moyenne, mais supérieur a ceux
rapportés pour laplupart desparcours de graminées. En ce qui concerne les
analyses minerales macroscopiques et microscopiques, les chiffres enregistrés
étaientplus éleves que les valeurs correspondantes rapportées sur la plupart des
plantesfourrageres rencontrees en OUganda Enfin, une analyse des acides
amines a montré que du point de vue qualitatif, les proteines de la consoude
voyageuse etaient comparables a celles desfeuilles de la luzerne mais
superieures a celles desfeuilles de I'amarante.
La consoude voyageuse pent done itre utilisee comme complement des
légumineuses fourrageres, des graminees et des residus de récolte en vue d'une
production soutenue des animaux d'élevage en Ouganda.
INTRODUCTION
The majority of ruminant animals in Uganda depend wholly on grazing
unimproved natural pastures. These pastures are dominated by coarse and
stemmy grasses with low dry-matter yield and nutritive value. Hence animal
production is limited from such pastures. Very little attention has been given to
the development of suitable forage species and/or establishment of pastures
capable of sustaining high levels of animal productivity.
Cultivated comfrey {Symphytum officinale), often referred to as Russian or
Quaker comfrey, was introduced in Uganda in the 1950s. It is a perennial herb
with the arrangement of stems and leaves similar to that of the tobacco plant.
The root system of a well-established comfrey plant is fleshy and extensive. The
plant is semi-sterile and is propagated vegetauvely mainly through root cuttings
and root offsets.
Once comfrey plants are well established, plenty of vegetative material can
be harvested by cutting several times during the year; the plants regenerate
quickly because of the large food reserves in the roots. Comfrey could become a
major source of fresh herbage for most of the year in Uganda where there is
plenty of sunshine and rainfall. Comfrey is also the only known land plant that
extracts vitamin B12 from the soil (Odwongo et al, 1987). It also contains
alantoin which is used by herbalists for treating digestive disorders. However,
comfrey contains at least eight pyrrolizidine alkaloids which cause acute
necrosis of liver and lungs in cattle and horses (Culvenor et al, 1980).
Administration of comfrey pyrrolizidine alkaloids to rats resulted in mortality
and liver damage (Culvenor et al, 1980).
250
Because little is known in Uganda about the agronomy and nutritive value
of comfrey, a study was carried out to study its growth characteristics and
nutrient composition.
MATERIALS AND METHODS
The study was conducted at Makerere University Research Institute, Kabanyolo,
19 km north of Kampala (0° 28' N, 32° 37' E; altitude 1200 m). The upland soils
of Kabanyolo are classified as ferralitic soils. The area has a moist tropical
climate with mean maximum temperatures varying from 28.5°C in January to
26.0^ in July and minimum temperatures ranging from 17.4°C in April to
15.9^ in July. Mean annual rainfall is about 1300 mm, with peaks in April and
November and two periods of low rainfall in January and July when the monthly
mean drops to 60 mm.
Russian comfrey was planted as offsets with 8 cm of cut root buried into the
ground at a spacing of 1 x 1 m in a 0.2-ha plot. Weeding was carried out every
three weeks after planting.
Comfrey was harvested at weekly intervals from eight to 12 weeks after
planting. (Harvesting was stopped at 12 weeks of growth because the plants had
become very coarse. They were also heavily infested with blight caused by
Cladosporium sp, indicating that bacterial blight is potentially a major disease of
comfrey in Uganda.) Regrowth materials were harvested after four, five and six
weeks of regrowth. For each harvest, 12 plants were randomly selected from
each quarter of the field, cut about 2.5 cm above ground, weighed and
subsampled. The subsamples were dried to constant weight in an air-draught
oven at 65 °C and then ground through a 1-mm sieve for chemical analysis
(AOAC, 1980). Amino acid profiles were determined by high performance
liquid chromatography (Waters/Millipore). Minerals were assayed by atomic
absorption spectrophotometry.
RESULTS AND DISCUSSION
Dry-matter (DM) and crude-protein (CP) yields of the comfrey plants are shown
in Table 1. These DM yields are lower than that obtained from a comfrey field
planted at a spacing of 0.9 x 0.9 m in Kenya—a total of about 40 t/ha from 12
monthly harvests, equivalent to a monthly yield of 3.4 t/ha (Anon, 1960). The
differences in the yields may be due to variations in spacing, soil fertility, stage
of plant establishment and plant variety. Most of these factors remain to be
defined for comfrey production in Uganda.
There was a steady increase in CP yield during both growth and regrowth
(Table 1), but CP content stayed constant at about 16%. This is comparable to CP
values of good to medium quality forage legumes but higher than for most
pasture grasses (Soneji et al, 1971; Sabiiti and Mugerwa, 1990).
251
Table 1. Russian comfrey dry-matter and crude-protein yields and contents during cutting trials
Dry matter Crude protein
Cutting time Yield (t/ha) Content (%) Yield (kg/ha) Content (%DM)
Weeks of growth
8 2.11 13.74 343.93 16.30
9 248 13.27 409.94 16.53
10 260 1289 440.70 16.95
11 3.64 14.96 591.86 16.26
12 3.34 14.44 516.70 15.47
Weeks of regrowth
4 206 1287 339.49 16.48
5 288 1238 419.04 14.55
6 258 1248 408.67 15.84
During all harvests, the comfrey plants had higher contents of both macro-
and micro-minerals (Table 2) than are usually observed in many fodder crops
(Kabaija and Smith, 1988). Similar results have been reported from studies in
Britain and New Zealand (Anon, 1960). The potassium content is very high,
which may indicate that comfrey plants have a high requirement for potash
fertiliser. However, Hart (1972) attributed the high potassium content of comfrey
plants to soil clinging to the hairy leaves during harvest. It was not possible to
estimate the contribution of such contamination to the values observed in the
present study.
Table 2 Mineral content ofRussian comfrey during cutting trials
Content (%DM)
Cutting time Calcium Phosphorus Potassium Magnesium Iron Copper Sulphur
Weeks of growth
8 1.94 0.51 8.07 0.41 0.27 0.0019 0.26
9 1.90 0.44 7.11 0.45 0.45 0.0021 0.23
10 1.95 0.45 6.47 0.42 0.42 0.0017 0.23
11 1.86 0.45 7.03 0.45 0.45 0.0016 0.22
12 1.56 0.41 6.11 0.38 0.38 0.0016 0.21
Weeks of regrowth
4 1.80 0.48 7.00 0.39 0.39 0.0018 0.22
5 1.90 0.43 7.40 0.40 0.39 0.0018 0.22
6 2.24 0.45 6.90 0.55 0.55 0.0012 0.22
252
Table 3. Amino acidprofiles ofRussian comfrey during cutting trials'
Content (%DM)
Weeks of growth Weeks of regrowth
Amino acid 8 9 10 12 4 5 6 Mean
Alanine 1.30 1.22 1.44 1.21 1.16 0.85 0.84 1.15
Arginine 1.13 0.99 0.95 0.90 0.94 0.64 0.57 0.87
Asparagine 1.95 1.95 - 1.85 1.94 1.59 1.74 1.84
Glutamine 2.09 1.86 1.92 217 238 1.95 2.26 209
Glycine 1.17 1.13 1.15 1.03 1.10 0.84 0.50 0.99
Histidine - - - 0.30 0.28 0.23 0.23 0.26
Isoleucine - - - - 0.86 0.88 0.60 0.78
Leucine - - - 0.86 1.38 1.12 0.98 1.09
Lysine - - - - 0.63 - 0.54 0.59
Proline 0.99 0.95 1.00 0.90 1.01 0.87 0.89 0.94
Phenylalanine - - - - 0.96 0.74 0.65 0.79
Serine 0.85 0.80 0.82 0.75 0.79 0.65 0.59 0.75
Threonine 0.95 0.92 0.90 0.75 0.84 0.65 0.57 0.80
Tyrosine - - - 0.58 0.66 0.63 0.50 0.59
Valine 1.33 1.23 1.26 1.07 1.10 0.83 0.79 1.09
* Assays for methionine and tryptophane are not available
Amino acid profiles of comfrey are shown in Table 3. Amino acid content
tends to decrease as the plants mature. A comparison of essential amino acid
profiles (Table 4) indicates that the protein quality of comfrey is comparable to
that of good quality alfalfa but higher than that oiAmaranthus leaf meal. These
observations need to be confirmed through direct animal studies.
CONCLUSIONS
The results of this study suggest that comfrey could provide average monthly
yields of 2 t DM/ha, containing over 300 kg high quality crude protein and high
levels of minerals. It would therefore be worthwhile investing in comfrey
production for livestock feeding because these yields are higher than those of
most forage legumes and grasses available in Uganda.
REFERENCES
Anon. 1960. Comfrey report. The story of the world's fastestprotein builder. Ministry of
Agriculture, Nairobi, Kenya. 15 pp.
253
Table 4. Comparison ofessential amino acidprofile ofeggprotein (standardprotein) with those
ofleafmeals ofRussian comfrey, Amaranthus hybridus and alfalfa"
Amino acids as % crude protein
% deficiency
Amaranthus
compared
protein
with egg
ComfreyAmino acid
Egg
protein
Amaranthus
(29% CP)
Alfalfa
(23%
CP)
Comfrey
(16%
CP) Alfalfa
Arginine 6.60 5.86 5.65 5.44 11.2 14.4 17.6
Histidine 2.40 1.45 1.74 1.63 39.6 27.5 32.1
Isoleucine 6.60 2.79 4.35 4.88 57.7 34.1 26.1
Leucine 8.80 5.45 6.52 6.81 38.1 25.9 22.6
Lysine 6.60 4.03 4.78 3.69 38.9 27.6 44.1
Phenylalanine 5.80 3.69 4.35 4.94 36.4 25.0 14.8
Threonine 5.00 3.82 3.48 5.00 23.6 30.4 0.0
Valine 7.40 3.52 4.78 6.81 52.4 35.4 8.0
* Assays for methionine and tryptophane of comfrey are not available
Sources: Amino acid profiles: egg protein and alfalfa leaf meal, NRC (1982); Amaranthus leaf meal,
01aboro(1975)
AOAC (Association of Official Analytical Chemists). 1980. Official methods ofanalysis.
13th edition. AOAC , Washington, DC, USA 1018 pp.
Culvenor C C J, Clarke M, Edgar J A Frahn J L, Jago M V, Peterson J E and Smith L W.
1980. Structure and toxicity of the alkaloids of Russian comfrey, a medicinal herb and
item of the human diet. Experientia 36:377.
Hart R H. 1972. Comfrey yields andforage value. United States Department of
Agriculture, Plant Physiology Institute, Beltsville, Maryland, USA 21 pp.
Kabaija E and Smith O B. 1988. Effect of season, fertilizer application and age of
regrowth on mineral content of guinea grass (Panicum maximum Schum) and giant
star grass (Cynodon nlemfuensis Chedda). In: Dzowela B H (ed), African forageplant
genetic resources, evaluation offorage germplasm and extensive livestockproduction
systems. Proceedings of the third workshop held at the International Conference
Centre, Arusha, Tanzania, 27-30 April 1987. PANESA (Pasture Network for Eastern
and Southern Africa). LLCA (International Livestock Centre for Africa), Addis Ababa,
Ethiopia. pp. 458-467.
NRC (National Research Council). 1982. United States-Canadian tables offeed
composition. National Academy Press, Washington, DC, USA ISO pp.
Odwongo W O, Bareeba F B and Mugerwa J S. 1987. The potential of Russian comfrey
as a feedstuff in Uganda. In: Sabiiti E N and Henderlong P (eds), Proceedings of the
first Uganda Pasture Network workshop. Makerere University, Uganda. pp. 30-40.
254
Olaboro G. 1975. Amaranthus leafmeed as a protein source in dietsfor broiler chick. MSc
Thesis. Makercre University, Kampala, Uganda. 71 pp.
Sabiiti E N and Mugerwa J S. 1990. Forage research and development for livestock
production in Uganda. In: Dzowela B H, Said AN, Asrat Wendem-Agenehu and
Kategile J A(eds), Utilization of research results on forage and agricultural
by-product materials as animalfeed resources in Africa. Proceedings of the first joint
workshop held in Lilongwe, Malawi, 5-9 December 1988. PANESA/ARNAB
(Pasture Network for Eastern and Southern Africa/African Research Network for
Agricultural By-products). ILCA (International Livestock Centre for Africa), Addis
Ababa, Ethiopia. pp. 186-206.
Soneji S V, Musangi R S and Olsen F J. 1971. Digestibility and feed intake investigations
at different stages of growth oiBracharia ruziziensis, Chloris gayana and Setaria
sphacelata. East African Agricultural and Forestry Journal 37: 125
255
256
COMPLEMENTATION DE LALIMENTATION DES
RUMINANTS DOMESTIQUES AVEC DE LA PAILLE ENRICHIE
AVEC DE L'UREEA4%
M. Doumbia et K. Cissoko
Centre de recherches zootechniques de Sotuba
B.P. 262, Bamako (Mali)
RESUME
Deux experiences ont ete menees au Mali en vue d' evaluer 1' eflet de la paille
enrichie avec de 1' uree sur la proaaction des ruminants.
Dans la première experience, 30 boeufs de labour de race Zébu maure, peul
et Mére ont eté divises en trois lots 6\e\6s pendant 63 jours sur paturage (lot
témoin), avec complement de paille enrichie (lot 2) ou de paille additionnee
d' aliment betail Huicoma (ABH) (lot 3). La consommation de complement du
lot 2 (2,28±0,28 kg/tSte/j) etait supdrieure a celle du lot 3 (1,86±0,45 kg/tete/j). II
n' y avait pas de difference significative entre les gains moyens quotidiens des
lots 2 (38,3 g) et 3 (53,9 g). Quant au lot témoin, il perdait en moyenne 148 g/j.
Dans la deuxieme experience, des ovins de race Djallonke métis et Bali Bali
et des caprins de race Djallonke ages de 24 a 48 mois ont eté elev6s sur paturage
avec divers complements alimentaires. Les variations de poids ont éte
enregistrees chez ces deux especes animales tandis que la production de lait a eté
analysée chez les seuls caprins. Une étude economique a montré que la
technique de production de paille enrichie utilisee etait a la portée des petits
eieveurs.
ABSTRACT
Supplementation ofruminant diets with 4% urea-enriched straw
Two experiments were carried out to evaluate the effect ofurea-enriched straw
on ruminant production.
In the first experiment, 30 Maure, Fulani andMeri Zebu work oxen were
divided into three groups and kept for 63 days on pasture (control) with two
types ofsupplements—enriched straw (Group 2) or straw with HuicomaAnimal
Feed (ABH) (Group 3). Group 2 consumed more supplement (2.28±0.28
kg/animalper day) than Group 3 (1.86±0.45 kg/animal per day). There was no
257
significant difference between the average daily weight gains ofanimals in
Group 2 (38.3 g) and Group 3 (53.9 g). The control animals lost weight.
In the second trial, West African Dwarfcross and Bali Bali sheep and West
African Dwarfgoats aged between 24 and 48 months were kept on pasture with
differentfeed supplements. Weight changes were recorded in both species while
milk production data were recorded only for goats. An economic analysis
showed that the enriched strawproduction technique used was within the reach
ofsmallholders.
258
EFFECT OF ADDITION OF CONCENTRATES TO SUDAN
GRASS (SORGHUMSUDANENSE) IN THE PRE-CALVING
PERIOD ON PERFORMANCE OF HOLSTEIN-FRIESIAN
HEIFERS IN SUDAN
A E El-Tayeb andA G Takla
Department of Animal Nutrition
Institute of Animal Production
University of Khartoum
PO Box 32, Khartoum North, Sudan
ABSTRACT
Holstein-Friesian heifers were used to study the effect of nutrition in late
pregnancy on early lactation performance. Before calving heifers were fed 10 kg
Sudan grass (Sorghum sudanense) per head per day, supplemented with 6 kg
concentrate supplement for 43 days (treatment 1); 6 kg concentrate for 60 days
(treatment 2); or 8 kg concentrate for 60 days (treatment 3). During the early
lactation period all the animals were fed 10 kg Sudan grass per day plus
concentrate ad libitum.
Average daily liveweight gains during the steaming-up period were not
different (P>0.05) among treatments. The level of concentrate feeding affected
(P<0.05) calf birth weight; calves born to heifers on treatments 2 and 3 were 7
and 8% heavier, respectively, than those born to heifers on treatment 1. No
differences (P>0.05) were observed among the treatment groups in average daily
gain after calving or in milk fat percentage. However, heifers on treatment 3
produced more milk than those on treatment 1.
RESUME
Performances post-partum de genisses croisees Holstein x race frisonne
alimenUes avant le velage avec du fourrage de sorghofourrager (Sorghum
sudanense; complement avec des concentres
L'effet du régime alimentaire vers lafinde la parturition a eté etudie sur les
performances de lactation post-partum de genisses metisses Holstein x race
frisonne. Avant le vilage, le regime alimentaire des animaux etaix compose de 10
259
kg de fourrage parjour complemente soit avec 6 kg de concentrésparjour et
par animalpendant 43 jours (traitement 1) ou 60jours (traitement 2) soit avec 8
kg de concentrés pendant 60jours (traitement 3). Au debut de la lactation, le
régime alimentaire était constitui de 10 kg de sorgho fourragerparjour
complemente avec des concentrés ad libitum.
Les traitements n'avaient aucun effet significatif (P>0,05) sur les gains
moyens quotidiens enregistrés avant la parturition. En revanche, ils avaient une
influence significative (P<0,05) sur lepoids des veaux à la naissance: ceux nés
de femelles préalablement soumises aux traitements 2 et 3 pesaient
respectivement 7 et 8% de plus que ceux dont la mere avait éte soumise au
traitement 1. Par ailleurs, le type de ration n'avait d'effet ni sur les gains
moyens quotidiens post-partum, ni sur le taux butyreux du lait produit. Toutefois,
la production de lait des animaux préalablement soumis au traitement 3 était
supérieure à celle des autres génisses.
INTRODUCTION
Many tropical and subtropical countries are importing exotic breeds of dairy
cattle or up-grading local types in an attempt to meet the local demand for milk
and milk products. However, imported animals rarely achieve the levels of
production that they show in their original habitats. Nutrition seems to be the
major factor limiting the productive and reproductive performance of such
animals.
Management practices in the tropics normally emphasise nutrition of
milking cows and neglect, to some extent, nutrition of heifers and dry cows.
Therefore, the aim of this work was to study the effects of feeding period and
level of concentrate supplements in late pregnancy on post-calving performance
of Holstein-Friesian heifers.
MATERIALS AND METHODS
The study used 18 in-calf heifers (liveweight 320-420 kg: average 359 kg) born
in Sudan to Holstein-Friesian cows imported as in-calf heifers in October 1984.
Because the experimental animals were selected randomly from a large herd
which was housed and managed as one group, they were given one week to
adapt to the experimental handling. They were then blocked, according to
liveweight, into three groups, of six animals each. All animals were fed a daily
ration of 10 kg Sudan grass (Sorghum sudanense) and, in addition, the groups
were randomly assigned to three dietary treatments:
• Group 1: 6 kg concentrates/head per day for 43 days pre-calving
• Group 2: 6 kg concentrates/head per day for 60 days pre-calving
• Group 3: 8 kg concentrates/head per day for 60 days pre-calving
All the animals were housed and fed individually.
260
The forage was offered in one meal at 1300 hours and concentrates were
offered in two meals at 0800 and 1700 hours; the compositions of the feed
ingredients are shown in Table 1.
After calving all animals were group fed 10 kg Sudan grass per head per
day plus concentrates ad libitum.
Animals were machine-milked every 12 hours, at 0400 and 1600 hours;
milk yield was recorded at each milking. Milk samples were collected once a
week and tested for butter-fat content by the Gerber method.
Liveweight changes during the pre- and post-calving periods were assessed
by weighing each animal once a week at 0700 hours, before the morning meal.
Calves were weighed immediately after calving. After calving, mastitis was
kept at a minimum level by strict sanitary control (including good hygiene and
teat dipping), and all calvers were tested for mastitis by rapid mastitis test at
monthly intervals. Ticks were controlled by spraying with Gamatox.
Data were subjected to analysis of variance applicable to a randomised
complete-block design (Steel and Torrie, 1980).
RESULTS
Animals in group 3 achieved higher liveweight gains than animals in the other
two groups (Table 2), but the differences were not significant (P>0.05).
Calves born to heifers on treatment 2 (mean weight 34.6 kg) and 3 (34.8 kg)
were heavier (P<0.05) than those born to heifers on treatment 1 (32.3 kg).
Composition (%)
Pre-calving Post-calving
Ingredient concentrate concentrate Sudan grass
Sorghum grain (dura) 40 35
Cottonseed cake 30 35
Wheat bran 28 28
Salt (NaCl) 1 1
Limestone 1 1
Chemical composition*
Dry matter 93.6 94.1 45.0
Ash 5.8 5.9 123
Crude protein 13.7 15.8 6.7
Crude fibre 12.8 115 50.5
Ether extract 3.8 5.1 1.2
Nitrogen-free extract 57.5 55.8 29.3
Table 1. Composition and analysis offeed ingredients used in the feeding trial
* Determined according to AOAC (1980)
261
Iiveweight at calving did not differ (P>0.05) among the treatment groups
(Table 3). There were also no significant differences in average daily gain and
final body weight at the end of the early lactation period.
Milk yields and fat percentage in early lactation are shown in Table 4.
Heifers in group 1 clearly produced more milk than those in group 1, but
butter-fat percentage did not differ (P>0.05) among treatments.
DISCUSSION
Heifers on treatments 2 and 3 appeared to be superior to heifers on treatment 1 in
final body weight and Iiveweight gain before calving, but the differences were
not significant. The apparent comparative rapid increase in the rate of weight
Table 2. Effect ofpre-calving nutrition on performance ofheifers in the pre-calving period
Treatment Steaming-up period
Average body weight (kg)
. Average daily gain
group (days) Initial Final (kg)
1 43 358.0 411.2 1.2
2 60 359.0 438.6 1.3
3 60 359.0 4513 1.5
SE 14.1 15.4 0.3
Table 3. Effect ofpre-calving nutrition on performance ofheifers in the early lactation period
Iiveweight
Treatment Early lactation at calving Final body weight Average daily gain
group (days) (kg) (kg) (kg)
1 98 355.3 455.0 1.0
2 98 388.3 4645 0.8
3 98 396.0 473.7 0.8
SE 14.1 16.1 0.1
Table 4. Effect ofpre-calving nutrition on milk yield andfat content in the early lactation period
Treatment Milking period
Milk yield (kg)
Fat content
group (days) Total Daily average (%)
1 91 980.2 10.7 3.9
2 91 1030.1 11.3 4.1
3 91 1329.2 14.6 3.9
SE 127.6 1.4 0.2
262
gain as calving approached, for heifers on treatments 2 and 3 compared with
those on treatment 1, was probably due to availability of nutrients which catered
for both dam and foetus growth. This agrees with previous work (Greenhalgh
and Gardner, 1958) which showed that the increased weight of heifers in the
later stages of pregnancy, as a result of an increase in concentrate feeding, was
related to the increase in weight of mother and foetus and its membranes at this
time.
The observed improvement in milk yield of heifers on treatment 3
compared with that of those on treatments 1 and 2 indicates that supplementation
with high levels of concentrates before calving tends to cause heifers to exhibit
their potentials in milk production. This is in line with previous studies (Keys et
al, 1984; Nocek et al, 1986) which showed that feeding cows and heifers at high
levels before calving resulted in better body condition at calving and better
production performance after calving. This may be attributed mainly to
availability of enough nutrients during the later stages of gestation, which would
enable the dam to meet the increased nutrient requirements of lactation.
Milk fat contents were not significantly different (P>0.05) among
treatments. Gardner (1969) also showed that milk fat percentages were not
influenced by preparfum plane of nutrition.
REFERENCES
AOAC (Association of Official Analytical Chemists). 1980. Official methods ofanalysis.
13th edition. AOAC, Washington, DC, USA 1018 pp.
Gardner R W. 1969. Interactions of energy levels offered to Holstein cows prepartum and
postpartum. Production responses and blood composition changes. Journal ofDairy
Science 52:1973-1984.
Greenhalgh J F D and Gardner K E. 1958. Effect of heavy concentrate feeding before
calving upon lactation and mammary gland oedema. Journal ofDairy Science
41:822-829.
Keys J E, Pearson R E and Miller R H. 1984. Effect of ratio of corn silage and
grass-legume silage with high concentrate during dry period on milk production and
health of dairy cows. Journal ofDairy Science 67:307-312.
Nocek J F, Steel R L and Braud D G. 1986. Prepartum grain feeding and subsequent
lactation forage program effects on performance of dairy cows in early lactation.
Journal ofDairy Science 69:734—744.
Steel R G D and Torrie J H. 1980. Principles andprocedures ofstatisticsA biometrical
approach. 2nd edition. McGraw Hill, New York, USA633 pp.
263
264
CAGED-LAYER WASTEAS A NITROGEN SOURCE IN
CROP-RESIDUE UTILISATION
S B Kayongo, MM Wanyoike, PNNyagah, TE Maitho andPN Mbugua
Department of Animal Production
Faculty of Veterinary Medicine
University of Nairobi
PO Box 29053, Nairobi, Kenya
ABSTRACT
Poultry litter has a crude-protein content of about 22-25% and has been
successfully used as a component of ruminant feeds. However, poultry waste is a
potential carrier of pathogenic microorganisms and must be treated to reduce the
risk of transmitting diseases. This study assessed the effect of sun-drying,
ensiling, deep-stacking and fumigating with formaldehyde gas on the nutritional
value of caged-layer waste (CLW). Deep-stacking resulted in a higher (P<0.01)
ash content and undesirable odour, but also in a higher (P<0.01) dry-matter
degradability (DMD) than the other treatment methods. Duration of sun-drying
or deep-stacking or the number of times the CLW was fumigated did not affect
(P>0.05) DMD in the rumen. However, ensiling CLW for 42 days resulted in a
higher (P<0.01) DMD than ensiling for 21 days and also reduced odour.
In another study, CLW was ensiled in 21-litre plastic silos for 21 or 42 days,
at 0, 20 or 40% (DM basis) rate of inclusion with crop residues having low
crude-protein levels (maize stover, maize cobs or wheat straw). Fermentation (as
indicated by pH) approached optimum (P<0.01) at 40% rate of CLW inclusion
and 42 days of ensiling. Crude-protein, ash and in vitro dry-matter digestibility
increased with level of CLW in the silage mixtures but NDF decreased (P<0.01).
Ensiling fibrous crop residues with caged-layer waste could provide a means of
more efficiently utilising caged-layer wastes and crop residues as livestock feed.
RESUME
Utilisation des dejections de pondeuses elevees en batteries comme source de
complement proteique des residus de recolte
Avec une teneur enprotéines brutes d'environ 22 a. 25%, la litiere de volatile est
incorporée avec succes dans I'alimentation des ruminants. Cependant, etant
265
donne qu'elles peuvent transmettre des microbes, les déjections des volailles
doivent itre traitees pour reduire les risques de maladies. Une etude a été
effectuee en vue d'evaluer I'effet du séchage solaire, de I'ensilage, de I'empilage
etdela fumigation au formol sur la valeur nutritive des dejections de volailles.
Par rapport aux autres méthodes, I'empilage, qui s'accompagnait d'odeurs
désagréables, se traduisait par une plus forte teneur en matieres minerales et un
taux de degradation de la matiere seche plus éleve (P<0,01). Ni la durée du
séchage a I'air et de I'empilage, ni le nombre defumigations n'avaient d'effet
(P>0,05) sur la digestibilite de la matiere seche dans le rumen. Cependant, un
ensilage de 42 jourspermettait de réduire les mauvaises odeurs et se traduisait
en outre par une digestibilite de la matiere seche plus élevée (P<0,01) qu'un
ensilage de 21 jours.
Dans une autre etude effectuee immédiatement apres, des dejections de
pondeuses en batteries ont été ensilees pendant 21 ou 42 jours dans des silos en
plastique (environ 21 litres). Elles avaient été incorporées a 0, 20 ou 40% (sur la
base de la matiere seche) dans des residus de recolte pauvres en proteines brutes
(paille de mats, epis égrenés de mats ou paille de ble). La fermentation (mesurée
par lepH) était maximum (P<0,01) au taux de 40% et avec I'ensilage de 42
jours. Enfin, la teneur en proteines brutes, le taux de matieres minerales et la
digestibilite in vitro de la matiere seche augmentaient alors que la teneur en
parois cellulaires diminuaient (P<0,01) avec la proportion de dejections.
L'ensilage des residus de recolte riches en cellulose avec des dejections de
pondeuses en batteries pent done permettre d'utiliser I'un et I'autreproduits de
maniereplus rationnelle.
INTRODUCTION
In Kenya, crop farming produces a wide range of crop residues, mainly maize
cobs, maize, sorghum and millet stovers and wheat, barley and rice straws. Other
important crop residues are produced by the sugar industry and from
horticultural crops. An estimated 7.2 million tonnes of highly lignified arable
farm products are produced annually (Said and Wanyoike, 1987). However, it is
difficult to assess the amounts of crop residues fed to livestock as there are great
variations with season and individual farm requirements.
Most available crop residues have low protein and high fibre contents,
factors that lead to their poor utilisation by livestock (Said and Wanyoike, 1987).
Utilisation of the energy component of such materials by ruminants is highly
dependent on the efficiency of fermentative activity in the rumen (Mehrez et al,
1977) which depends, in turn, on adequate supplies of nitrogen in the rumen.
Positive responses on intake and liveweight gain have been recorded when a
nitrogen source has been included in a diet based on crop residues (Alayu, 1987).
In Kenya, most studies on crop residues have been on evaluating chemical
treatment methods such as the use of alkali and/or urea to improve utilisation
(Kevelenge et al, 1983; Alayu, 1987; Said and Wanyoike, 1987). However, the
266
applicability of results from such work has been limited by the high cost of
chemicals and by farmers' lack of knowledge. The need has thus arisen to find
alternative, more practical, ways to improve the nutritive value of crop residues.
Caged-layer waste (CLW) is reported to contain between 22.3 and 25%
crude protein (Kayongo and Muinga, 1985; Nambi, 1987). Between 40 and 50%
is true protein and the rest non-protein nitrogen (Nambi, 1987). However,
feeding unprocessed CLW can pose potential health hazards, both to the
livestock consuming the feed and to people eating products (meat and milk)
from such animals (Shah and Muller, 1983). Ensiling is an inexpensive
biological method of processing poultry litter for incorporation into rations
(Caswell et al, 1977; Shah and Muller, 1983). It has also been reported that
ensiling broiler litter with corn forage or wheat straw improved the nutritional
value of the crop residues compared to ensiling the crop residues by themselves
(Caswell et al, 1977; Daniels et al, 1983). This study therefore examined the
effect of processing methods on the composition and degradability of CLW. The
effect of ensiling CLW (as a nitrogen source) with crop residues on the chemical
composition and degradability of the silage was also investigated.
MATERIALS AND METHODS
Experiment 1. Processing methods
Caged-layer waste was collected from laying Shavers chickens, aged 50 weeks
and housed in battery cages. Apolythene sheet was spread below the cages and
the droppings, which included excreta, feathers, broken eggs and spilled feed,
were collected after three days. The waste was processed by one of four
methods, all applicable at farm level in Kenya:
Sun-drying. Caged-layer waste was spread on polythene sheets in 1-2-cm
thick layers and raked thoroughly twice a day. Drying lasted four or eight days at
an average temperature of 25.74°C and radiation intensity of 20.37 MJ.
Ensiling. Caged-layer waste was packed into plastic silos with a capacity of
0.021 m (21 litres) and left for either 21 or 42 days. Samples were taken at
ensiling and after opening the silos.
Deep-stacking. Deep-stacking was achieved by heaping approximately
1000 kg of caged-layer waste on a concrete floor under direct sunshine. The
stack was then covered with a polythene sheet and sampled after 21 or 42 days
by taking composite samples from the entire stack.
Fumigation. Caged-layer waste was spread on perforated trays in layers
0.5-1 cm thick and sun-dried for two days. The trays were then placed in an
air-tight metal chamber with a capacity of 0.81 m . The chamber was fumigated
using a 1:2 mixture of potassium permanganate and 40% formalin in a glass jar:
the amount of formalin used was 1.85 ml per chamber. Fumigation was carried
out four or eight times: the CLW was turned by hand after each fumigation
267
All samples were dried in an oven at 60°C for 48 hours, ground in a Wiley
mill fitted with a 2-mm screen and stored in air-tight bottles.
In sacco dry-matter degradability studies were carried out using five
fistulated Somali Blackhead wether sheep (15-18 months old; average weight
32.4 kg.) The sheep were fed Rhodes grass (Chloris gayana) hay and
supplemented with a commercial concentrate at a rate of 0.3 kg/animal per day.
The animals were dewormed with Valbazen 10% (Kenya Swizz Chemical
Company, Nairobi, Kenya) at a rate of 1 ml per 10 kg body weight one week
before the start of the study.
Samples (5 g) of each feed were weighed into nylon bags (15 x 7 cm: pore
size of 35 um). The bags were attached to nylon cords and incubated inside the
rumens of the sheep for 6, 12, 24, 48 or 72 hours. After incubation the bags were
removed, washed thoroughly with tap water, dried at 70°C in an oven for 24
hours and weighed to calculate dry-matter losses (0rskov and McDonald, 1979).
The experimental layout was a 4 x 2 x 5 factorial arrangement in a completely
randomised design, with four treatment methods at two levels each and five
durations of incubation in the rumen. Unprocessed CLW was used as the control
giving a total of nine test feeds.
Experiment 2. Effect of ensiling crop residues with graded levels of
caged-layer waste
Maize stover and cobs and wheat straw were cut into 2.5-5-cm lengths; water
was added at a ratio of 1:1 to increase moisture content. Freshly collected caged-
layer waste was mixed with the crop residues at a rate of 20 or 40% (dry-matter
basis): no CLW was added to the control materials. Molasses was added to all
ensilages at a rate of 5%. The ensilage materials were thoroughly mixed by hand
and packed in 21-litre plastic silos in triplicate. The silos were opened after 21 or
42 days. The top 2.5 cm of the silage from each silo was discarded. The silages
were observed for colour, odour and any mould growth.
Proximate composition of crop residues, molasses, CLW and silages before
and after fermentation was determined using standard AOAC (1984) procedures.
Detergent fibres were analysed by the methods of Van Soest (1963) and Van
Soest and Wine (1967). In vitro dry-matter and organic-matter digestibilities of
the crop residues, CLW and silages were determined by the methods of Tilley
and Terry (1963). Water extracts of the silages were prepared by homogenising
25 g of wet silage with 100 ml distilled water in a blender for two minutes. The
homogenate was filtered through four layers of cheese cloth and its pH measured.
The rest of the silages were dried at 60°C for 48 hours, milled through a
2-mm sieve and stored in air-tight jars. Samples (5 g) of each milled silage were
weighed into nylon bags and incubated for 12, 24, 36, 48 or 72 hours in the
rumens of the same sheep used in Experiment 1. A completely randomised
design with a factorial arrangement of 3x3x3x5 (three crop residues, at three
levels of CLW, three durations of ensiling and five incubation times) was used.
268
Calculations
In both experiments, degradability was estimated using the model developed by
0rskov and McDonald (1979):
p = a + b(l-e~ct)
where:
p = actual degradation after time t
a = readily degradable fraction (%)
b = potential degradable fraction (%)
c = rate constant for the degradation of b
t = incubation time (hours).
The constants a, b, and c were derived using EUREKA an iterative
computer programme (Borland International Inc). The data obtained were
subjected to analysis of variance using Harvey's Least-Squares analysis. The
differences between treatment means were tested with orthogonal contrasts.
RESULTS AND DISCUSSION
Experiment 1
Chemical composition ofunprocessed andprocessed CLW
The proximate compositions of unprocessed, sun-dried, ensiled, deep-stacked
and fumigated CLW are shown in Table 1. Dry-matter (DM) content increased
with increasing duration of sun-drying and deep-stacking as has also been
reported by Fiano et al (1984) when CLW was sun-dried for 30 days. Fumigated
CLW also had a higher DM content than fresh CLW. However, ensiling did not
change the DM content of CLW. Crude-protein (CP) content had declined
sharply after sun-drying for four days, but thereafter the decrease was negligible;
this result is also in agreement with the study by Fiano et al (1984). The loss in
CP was attributed to the breakdown of uric acid (Caswell et al, 1975) which
constitutes 40 to 50% of total nitrogen in CLW (Nambi, 1987). Direct sunlight
could have caused volatisation of the uric acid (Fiano et al, 1984); Caswell et al
(1975) showed that dry-heat processing of broiler Utter lowered the uric acid
nitrogen as well as ammonia nitrogen. Other treatment methods did not affect the
CP values significantly.
Deep-stacking increased the ash content of CLW suggesting that CLW
underwent a composting process in which the organic matter might have been
converted into soluble materials (Miiller, 1982). This increase in ash content
might reduce the digestible energy of CLW and hence its nutritional value
(Muller, 1982). The other methods had no effect on ash content of CLW; this
result is in agreement with observations by Fiano et al (1984) from air-drying,
autoclaving and oven-drying of CLW.
269
Table 1. Chemical composition ofunprocessed andprocessed caged-layer waste
Proximate component (%)
Processing method Dry matter Ash Crude protein
Unprocessed 31.02 20.50 21.80
Sun-drying
4 days 81.44 21.57 13.13
8 days 90.12 20.22 12.76
Ensiling
21 days 28.88 23.92 17.29
42 days 29.41 23.80 18.72
Deep-stacking
21 days 54.17 33.56 16.38
42 days 78.10 35.45 17.20
Fumigation
4 times 77.32 21.04 17.97
8 times 76.52 20.98 16.55
Degradation characteristics ofunprocessed andprocessed CLW
Dry-matter degradabilities (DMD) of unprocessed and processed CLW are
shown in Tables 2 and 3. Deep-stacked CLW had a higher DMD (P<0.01) than
CLW processed by the other methods, whose DMD were similar (P>0.05).
However, the deep-stacked CLW had an offensive odour. DMD increased
(P<0.01) with incubation time for all methods of processing, as has also been
reported by Alayu (1987).
Sun-drying for four or eight days, deep-stacking for 21 or 42 days or
fumigation four or eight times did not affect DMD of CLW within method
(P>0.05). However, ensiling for 42 days gave superior (P<0.01) DMD than
ensiling for 21 days. This result agrees the finding of Daniels et al (1983) who
reported that ensiling broiler litter for 42 days gave better quality silage.
Experiment 2
Chemical composition ofcrop residues ensiled with CLW
Table 4 shows the chemical composition of the crop residues and molasses used
for ensiling with CLW. All the three crop residues had low crude-protein and
high crude-fibre and detergent fibre contents, in total agreement with reports by
Kevelenge et al (1983), Alayu (1987) and Tuah and 0rskov (1989). After
270
Table 2. Least-squares means ofthe effect ofmethod, level within method and time on dry-matter
degradability ofunprocessed or processed caged-layer waste
Independent variable Dry-matter digestibility (%)
Processing methods
Unprocessed 41.99
Sun-drying 41.67
EnsUing 43.85
Deep-stacking 53.42
Fumigation 43.63
SE 0.60
Level within method
Sun-drying
4 days 41.22
8 days 42.13
Ensiling
21 days 40.85
42 days 46.86
Deep-stacking
21 days 53.46
42 days 53.37
Fumigation
4 times 44.41
8 times 42.85
SE 0.85
Duration of incubation
6 hours 27.69
12 hours 33.67
24 hours 45.27
48 hours 54.98
72 hours 62.96
SE 0.64
ensiling, all silages that had CLW as an additive had a pleasant aroma, a
gold-brown colour and no mould growth. However, the control silages only had
a weak characteristic silage smell. Similar observations have been made on
poultry litter ensiled alone or with barley straw, a mixture of weeds and
grapefruit peels (Hadjipanayotou, 1982).
271
Table 3. Fitted dry-matter degradation constants for unprocessed andprocessed caged-layer
waste incubated in nylon bags in the rumen ofsheep
Degradation constants*
Method of processing a b c
Unprocessed 20.4 49.9 0.021
Sun-drying
4 days 20.9 51.9 0.019
8 days 13.6 51.3 0.034
Ensiling
21 days 15.6 43.8 0.036
42 days 22.1 66.5 0.017
Deep-stacking
21 days 24.5 53.0 0.026
42 days 29.4 45.3 0.030
Fumigation
4 times 18.9 57.6 0.022
8 times 19.2 39.3 0.040
"From the model p = a + b(l - e"0)
p = actual degradation after time t
a = readily degradable fraction (%)
b = potential degradable fraction (%)
c = rate constant for the degradation of b
t = incubation time (hours)
The pH values were not affected (P>0.05) by type of crop residue (Table 5).
However, maize stover and wheat straw silages had higher CP and ash and lower
neutral detergent fibre (NDF) (P<0.01) than silage based on maize cobs. These
changes could be attributed to the inclusion of CLW in the mixtures. As the level
of CLW was increased from 0 to 40% there was a significant increase in pH, CP,
ash and in vitro dry-matter digestibility (IVDMD) of the resultant silage whereas
NDF values decreased. Similar findings have been reported by Daniels et al
(1983) and Hadjipanayotou (1984). Ensiling for either 21 or 42 days had no
effect on ash and NDF content of the silages (P>0.05) but significantly decreased
pH (P<0.01) suggesting that desirable fermentation had taken place (Daniels et
al, 1983).
Degradability of crop residues silages
Wheat straw silage had a higher degradability (P<0.01) value than maize stover
and maize cob silages (Table 6), probably because of higher readily soluble cell
contents (Tuah and 0rskov, 1989). Tables 6 and 7 show that increasing the level
272
Table 4. Chemical composition ofmaize stover, maize cobs, wheat straw,
molasses used in Experiment 2
(%)
caged-layer waste and
Component
Maize
stover
Wheat
straw
Maize Caged-layer
cobs waste Molasses
Dry matter 94.30 94.30 91.76 30.65 67.74
Crude protein 4.60 3.64 4.20 22.5 3.40
Ash 3.20 2.32 4.68 20.36 8.32
Crude fibre 45.70 47.86 48.61 6.69 0
Neutral detergent fibre 85.25 84.28 91.84 57.65 -
Acid detergent fibre 58.0 58.79 44.84 22.80 -
Lignin 8.40 733 14.96 6.12 -
Cellulose 49.60 51.46 29.88 16.68 -
Hemicellulose 26.75 25.49 47.0 34.85 -
Cell content 14.75 15.72 8.16 42.35 -
In vitro digestibility
Dry matter 30.32 29.84 43.58 7431 •
Organic matter 29.32 32.19 42.70 74.40 •
* Not assessed
Table 5. Least-squares means for chemical
ensiled with caged-layer waste
' composition and in vitro digestibility ofcrop residues
Crude
protein
In vitro dry-matter Neutral
digestibility detergent fibre
(%) (%)
Independent
variable
Ash
Crop residues
PH (%) (%)
Maize stover 4.36 931 10.89 6079 69.67
Wheat straw 4.09 9.11 10.09 57.41 67.12
Maize cobs 439 7.62 6.76 59.89 77.08
Level of caged-layer waste
0% 439 539 634 53.57 80.07
20% 4.72 9.03 9.51 60.93 70.40
40% 4.93 11.63 1271 63.60 63.40
Duration of ensiling
Odays 532 7.67 9.40 60.37 72.10
21 days 4.57 939 9.55 58.65 70.67
42 days 4.16 8.99 9.61 59.09 71.11
SE 0.03 0.13 0.24 0.33 0.43
273
Table 6. Least-squares means for dry-matter degradablity ofcrop residues ensiled with
caged-layer waste
Independent variable Dry-matter degradability (%)
Crop residue
Maize stover 39.16
Maize cobs 37.75
Wheat straw 41.03
SE 0.42
Level of caged-layer waste
0% 32.08
20% 39.83
40% 45.99
SE 0,12
Duration of ensiling
0 days 38.16
21 days 39.05
42 days 40.69
SE 0.42
Incubation time in the rumen
12 hours 22.09
24 hours 26.72
36 hours 35.65
48 hours 50.03
72 hours 5759
SE 0.60
of CLW in the ensilage significantly (P<0.01) increased the degradability,
probably because of increased nitrogen content (Alayu, 1987). There was an
increase (P<0.01) in degradability when the duration of ensiling was increased
from 21 to 42 days suggesting that a longer period was desirable to facilitate
microbial activity on the ensiled crop residues (Daniels et al, 1983). Alayu
(1987) reported that extending treatment time for wheat straw from 14 to 28 days
improved the DM degradability. The increase in degradability of the silages with
longer duration of ensiling could be attributed to the increased degradability of
CLW observed in Experiment 1 when CLW was ensiled for up to 42 days. The
longer the silages were incubated in the rumen the higher was the degradability,
in agreement with earlier studies on wheat straw treated with urea (Alayu, 1987).
274
Table 7. Fitted dry-matter degradation constants for crop residues ensiled with caged-layer waste
Duration of ensiling Level of CLW
Degradation constants'
Crop residue (days) (%) a b c
Maize stover 0 0 7.9 55.7 0.011
20 13.1 78.3 0.011
40 19.8 78.8 0.014
21 0 13.9 62.8 0.010
20 16.3 64.1 0.014
40 19.4 67.1 0.017
42 0 10.9 86.1 0.010
20 15.6 72.9 0.023
40 21.3 66.4 0.030
Maize cobs 0 0 11.1 45.9 0.009
20 16.0 59.5 0.011
40 18.5 62.8 0.013
21 0 12.2 48.5 0.011
20 125 58.5 0.017
40 19.3 64.9 0.021
42 0 13.5 53.9 0.011
20 13.4 52.4 0.018
40 14.5 69.6 0.024
Wheat straw 0 0 125 52.9 0.013
20 15.6 67.2 0.013
40 15.9 76.2 0.020
21 0 13.3 55.9 0.013
20 14.1 52.7 0.018
40 16.4 75.2 0.019
42 0 10.2 64.0 0.013
20 17.5 71.3 0.019
40 17.9 72.0 0.023
'From the model p = a + b(l - e-01)
p = actual degradation after time t
a = readily degradable fraction (%)
b - potential degradable fraction (%)
c = rate constant for the degradation of b
t = incubation time (hours)
275
CONCLUSIONS
The study showed that processing CLW by deep-stacking gave best results with
respect to DM degradability. However, the steep increase in the ash content was
indicative of composting, which might reduce the nutrient utilisation of deep-
stacked CLW. Therefore, ensiling for 42 days would be preferred for odour
control of the processed product. Ensiling crop residues with CLW as the
additive at an inclusion rate of 40% and ensiling for 42 days was considered to
be beneficial in improving the nutritional value of the crop residues.
Investigations into the performance of growing sheep fed such silage are
underway at the University of Nairobi.
ACKNOWLEDGEMENT
This study was funded by the Norwegian Agency for International Development
(NORAD, Project KEN 046) to which the authors are grateful.
REFERENCES
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supplemented wheat straw. MSc Thesis. University of Nairobi, Nairobi, Kenya.
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from incubation measurement weighted according to rate of passage. Journal of
Agricultural Science, Cambridge 92:499-503.
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277
278
EFFECTS OF UREATREATMENT OF MAIZE STOVERAND
SUPPLEMENTATION WITH MAIZE BRAN OR
UREA-MOLASSES BLOCK ON THE PERFORMANCE OF
GROWING STEERS AND HEIFERS
J TKMunthali, CNJayasuriya andA NBhattachrya
Chitedze Agricultural Research Station
PO Box 158
Lilongwe, Malawi
ABSTRACT
Maize stover is an important feed resource in Malawi, but it is poorly utilised.
Simple methods of processing and/or treating the stover to optimise its utilisation
by stall-fed cattle are being sought. An experiment was conducted at the
Chitedze Agricultural Research Station during October to mid-December 1990 to
assess the effects of water or urea treatment of maize stover and supplementation
with urea-molasses blocks or different levels of maize bran on the growth of
yearling steers and heifers.
Animals fed water-treated stover without supplementation lost weight and
had the lowest crude-protein intake, indicating that this diet was deficient in
nitrogen. Urea treatment increased the crude-protein content of maize stover
four-fold compared with untreated stover. Water or urea treatment of maize
stover did not affect stover dry-matter or total dry-matter intake. Supplementing
urea-treated stover with high levels of maize bran significantly (P<0.01)
increased liveweight gains.
RESUME
Performances de bouvillons et de génisses en croissance alimentes avec de la
paille de mats traitie avec de I'urée et complémentée avec du son de mats ou
un concentri de melasse-uree
Men qu'elle constitue I'une des principales sources d'aliments du betail
rencontrées au Malawi, la paille de mats estpeu utilisée dans cepays. Les
efforts deployés actuellement visent entre autres, a mettre au point des methodes
simples de transformation et/ou de traitement de ces residus de recolte afin d'en
optimiser I'utilisation dans I'alimentation des bovins a I'etable. A cet effet, un
279
essai a ete effectue d'octobre a la mi-decembre 1990 a la station de recherche de
Chitedze en vue de determiner I'effet, sur la croissance de bouvillons et de
genisses ages de 1 an, d'un regine alimentaire compose de paille de mats traitée
avec de I'eau ou de I'uree et complementée avec un concentre mélasse-uree ou
differents niveaux de son mais.
Les animaux recevant uniquement de la paille traitee avec de I'eau
perdaient depoids et consommaient moins deprotéines brutes que ceus soumis
aux autres regines alimentaires, ce qui signifie que cette ration présentait une
carence en azote. Le traiiement avec de I'uree permettait de quadrupler la
teneur enproteines brutes de la paille. Par ailleurs, le traitement avec de I'eau
ou de I'uree n'avait aucun effet sur I' ingestion de paille brute ou de matiere
seche totale. Enfin, la paille traitee avec de I'uree et complementée avec des
niveaux éleves de son de mais entrainait un accroissement significatif (P<0,01)
des gains de poids vif.
INTRODUCTION
Maize stover is the largest animal feed resource in Malawi following crop
harvests. Although it is widely acknowledged to be a useful feed, it is not utilised
efficiently; it is grazed in situ and so is subjected to trampling, soiling, termite
damage and fires. As a result, less than 50% of the available stover is actually
consumed by livestock.
Acute cattle feed shortages occur at the peak of the dry season (September
through November). The animals hardest hit are the stall-fed dairy cows and
their followers or fattening steers which, by regulation, are not supposed to graze
freely in order to avoid diseases and indiscriminate mating. For this group of
animals, improvements in the utilisation of maize stover and other crop residues
are essential in order to maintain productivity. In addition to proper storage of
maize stover, attempts are being made to integrate forage legumes in maize crops
and to find simple methods of processing and/or treating the stover to optimise
its utilisation by stall-fed cattle. Urea was chosen for treating maize stover
because, apart from its ability to increase the nitrogen content of the treated
stover, it is being vigorously promoted as a fertiliser, and hence is readily
available in the country, and farmers can handle it safely.
An experiment was conducted at the Chitedze Agricultural Research
Station, Malawi, during October to mid-December 1990 to assess the effects of
water or urea treatment of maize stover and supplementation with maize bran or
urea-molasses block on the growth of yearling steers and heifers. Specifically,
the objectives were to compare water-treated maize stover with urea-treated
maize stover, water-treated maize stover with and without urea-molasses block
supplementation, and urea-treated maize stover supplemented with three levels
of maize bran.
280
MATERIALS AND METHODS
Animals
The experimental animals were 40 yearling crossbred (Friesian x Malawi zebu)
cattle (22 steers and 18 heifers) that had been previously grazed as a group on
Rhodes grass (Chloris gayana) standing hay, maize stover and unimproved
dambo grasses. All animals were dewormed with Thibenzole at the start of the
experiment. They were then randomly allocated to five feeding treatment groups
(eight animals each), taking into account sex and initial liveweight differences.
Feeds
The animals were fed maize stover (treated with water or urea), groundnut tops,
Rhodes grass hay, maize bran, urea-molasses blocks and a mineral mixture.
Maize stover from the station was collected and chopped, using a forage
harvester, into pieces up to 14 cm long. The stover was ensiled in circular pits,
1.5 m in diameter and 2.0 m deep, with a seepage pit at the bottom. Weighed
batches of chopped stover were placed in the pit and sprayed (using a garden
watering can) with either plain water or a urea solution at the rate of 1.5 litres of
water/solution to 1 kg of stover. (Previous work (Munthali et al, 1990) had
shown that spraying at the rate of 1 litre of water to 1 kg of stover DM resulted
in inadequate wetting of the stover and hence poor chemical reaction.) The
amount of urea used was calculated to give a treatment of 4 g urea to 100 g
stover (ie, 4% urea-treated stover). The stover was mixed and trampled by two to
three people to compress it. More batches of stover were then added and treated
until the pit was filled. Finally, the pit was covered with polythene sheets and a
thick (about 45 cm) layer of soil.
Groundnut tops were also collected at the station and either baled or kept
loose in stooks under a barn. Hay was made from fully mature Rhodes grass,
baled and kept in a barn. Maize bran was purchased either from families in and
around the station or from Grain and Milling Company as a hominy chop (maize
germ meal).
Urea-molasses blocks were manufactured using fertiliser grade urea (45%
nitrogen) and type C cane molasses. The characteristics of the molasses and the
compositions of the urea-molasses block and of the mineral mixture (also
included in the urea-molasses blocks), are given in Table 1.
Feeding
Animals were fed in pairs at 0800 and 1400 hours.
During the first 10 days, animals were fed hay ad libitum and maize bran
(1.0 kg/animal per day). Thereafter, all animals were fed the experimental
281
Table 1. Characteristics of type C cane molasses and compositions ofurea-molasses-mineral
block and mineral mixture
Molasses*
Value
Molasses—urea-mineral block
Content
Mineral mixture
Content
(%DM) Component (g/kg) Component (g/kg)
Dry solids 78.8 Molasses 370 Meat and bone meal 600
Brix 77.4 Urea 100 Common salt 350
Sucrose 32.8 Maize bran 300 Magnesium sulphate 35
Polarisation 30.0 Salt 50 Copper sulphate 6
Total invert 50-56 Cement 130 Zinc oxide 8.5
Ash 13.7 Mineral mixture 50 Cobalt sulphate 0.2
Purity 38.8 Potassium iodide 0.3
'Source: Sugar Corporation of Malawi (SUCOMA), Personal communication, 1991
diet—a daily allowance of 1 kg groundnut tops, 0.5 kg hay and 0.05 kg mineral
mixture plus one of the following treatment diets:
• Diet 1: ad libitum water-treated maize stover plus 1.0 kg maize bran
Diet 2: ad libitum water-treated maize stover plus 1.0 kg maize bran plus
urea-molasses block for three hours
• Diet 3: ad libitum 4% urea-treated maize stover plus 1.0 kg maize bran
• Diet 4: ad libitum 4% urea-treated maize stover plus 2.0 kg maize bran
• Diet 5: ad libitum 4% urea-treated maize stover plus 3.0 kg maize bran
The experimental diets were first fed for a 22-day acclimatisation period,
during which time the animals on diet 2 were exposed to the urea-molasses
block for only one hour daily. The experimental period was 56 days, ending at
the onset of the rainy season.
Data collection
Quantities of feed offered and refused were recorded daily. Feed intake was
calculated from daily intakes on four consecutive days weekly. Urea-molasses
block intake per animal was calculated from the total number of blocks
consumed by each treatment group during the 56-day experimental period.
Initial and final liveweights were calculated as a mean of three consecutive
daily weights taken after depriving animals of water for approximately 16 hours.
RESULTS AND DISCUSSION
The chemical compositions of the feeds are shown in Table 2.
282
Table 2. Chemical compositions offeeds
Feed material Dry matter (%) Crude protein (% DM)
Maize stover
Untreated 91.7 2.8
Water-treated 43.3 3.5
4% urea-treated 35.9 14.4
Maize bran (madeya) 90.1 9.6
Groundnut tops 90.6 7.8
Rhodes grass nay 91.8 5^
The chemical compositions of groundnut tops, hay and maize bran were
similar to those commonly found in samples collected on the station. However,
crude-protein (CP) content of untreated stover was lower than that previously
reported by Munthali (1987). The stover used in the present experiment was
collected late in the dry season and exposure to varying climatic conditions may
have led to nitrogen degradation (Berger et al, 1979).
Urea treatment increased the CP of the maize stover more than four-fold.
Similar increases in CP content of forages following urea treatment have been
reported elsewhere (Jackson, 1978; Klopfenstein, 1978; Sundstol et al, 1978;
Kiangi, 1981). Therefore, urea treatment is a practical method of increasing the
nitrogen content of low quality roughages.
The observed differences in dry-matter (DM) content of the water- and
urea-treated maize stover may be attributed to sampling errors.
The performance of growing steers and heifers is shown in Table 3.
Crude-protein intake increased when animals were fed 4% urea-treated
maize stover. It declined as the amount of maize bran fed increased from 1.0 to
3.0 kg/animal per day because stover intake declined with increased feeding of
maize bran. The decline in CP consumption was due to the substitution of high N
urea-treated maize stover by maize bran. The intake of the urea-molasses block
was calculated to be 200.8 g/animal per day, giving a nitrogen consumption from
the block of approximately 90 g/animal per day. The anticipated intake of the
block was 300 g/animal per day, so the limited exposure time (three hours) of the
animals to the block probably lowered its intake.
Total DM intake did not vary greatly, and all animals appeared to have
satisfactory DM intakes of 3% or more of their body weights. Urea treatment of
maize stover did not increase DM intake compared with water treatment of the
stover. However, Smith et al (1989) reported significant increases in DM intake
of urea-treated maize stover compared with dry fresh maize stover, indicating
that water treatment followed by ensiling has a similar effect in increasing DM
intake to urea treatment followed by ensiling.
283
Table 3. Performance ofgrowing steers fed maize stover diets
Dietl Diet 2 Diet 3 Diet 4 Diet 5
Crude-protein content in diet
(% dry matter)b 5.7 5.7° 13.2 12.3 11.7
Stover dry-matter intake
kg/animal per day 3.56 3.71 4.46 3.46 2.99
% of body weight 1.86 1.98 229 1.76 1.55
Total dry-matter intake
kg/animal per day 5.80 5.95 6.70 6.58 6.99
% of body weight 3.02 3.17 3.44 3.36 3.63
Mean liveweight at start of
experimental period (kg)
187.1 197.1 201.0 2227 229.2
Daily gain during 56-day
experimental period (g)
Mean -83.0 170.6 116.1 483.0 649.8
SE 70.0 65.3 96.3 51.9 85.8
* Diets were:
Diet 1 : ad libitum water-treated maize stover + 1 kg maize bran + 1 kg groundnut tops + 500 g hay
+ 50 g mineral mixture
Diet 2: ad libitum water-treated maize stover + 1 kg maize bran + 1 kg groundnut tops + 500 g hay
+ 50 g mineral mixture + urea-molasses block
Diet 3: ad libitum 4% urea-treated maize stover + 1 kg maize bran + 1 kg groundnut tops + 500 g
hay + 50 g mineral mixture
Diet 4: ad libitum 4% urea-treated maize stover + 2 kg maize bran + 1 kg groundnut tops + 500 g
hay + 50 g mineral mixture
Diet 5: ad libitum 4% urea-treated maize stover + 3 kg maize bran + 1 kg groundnut tops + 500 g
hay + 50 g mineral mixture
Crude-protein content in maize stover was determined using fresh samples
c Urea N from urea-molasses block not included, but intake of nitrogen was 90 g/animal per day
The highest liveweight gain (P<0.01) was achieved by animals on diet 5,
the treatment with the highest level of maize bran supplementation. Animals fed
unsupplemented water-treated stover (diet 1) lost weight; these animals showed
the lowest crude-protein intake, indicating that diet 1 was deficient in nitrogen.
Supplementation of the water-treated stover with urea-molasses block (diet 2) or
treatment of the stover with urea (diet 3) was enough to support maintenance and
slight liveweight gains of the animals, further showing that nitrogen could have
been the limiting nutrient in diet 1. The improvement in liveweight gain by
animals on diets 4 and 5 could be attributed to the increased intake of energy and
an accompanying improvement in the utilisation of non-protein nitrogen in the
4% urea-treated maize stover. Early work by Pearson and Smith (1943), Arias et
al (1951) and Belasco (1956) showed that starch induced better utilisation of
non-protein nitrogen than any other carbohydrate source, and the maize bran
used in the present study is rich in starch.
284
CONCLUSIONS
Treatment of maize stover with water followed by ensiling gave comparable DM
intakes to that obtained when the stover was treated with 4% urea and ensiled,
although animals fed unsupplemented water-treated stover lost weight.
Supplementing water-treated stover with urea-molasses block, or treating the
stover with urea, was sufficient to support maintenance plus small liveweight
gains in cattle. Supplementing urea-treated stover with a suitable source of
energy (such as starch, as in maize bran) promoted high liveweight gains.
The experiment has demonstrated that an adequate supply of nitrogen is
essential to maintain cattle fed basal diets of maize stover, and that farmers could
supplement their animals with energy to promote faster liveweight gains, even
when the sole diet is treated maize stover.
ACKNOWLEDGEMENTS
We are grateful to Mr H K Chikhawo and Mrs C H Jere and their staff for the
daily management of the experiment, and to the nutrition laboratory staff at the
Central Veterinary Laboratory for analysing the feed samples and for
manufacturing the urea-molasses blocks. We are also very grateful to Ms D
Fatch for typing the manuscript.
REFERENCES
Arias C, Burroughs W, Gerlaugh P and Bethke R M. 1951. The influence of difference
amounts sources of energy upon in vitro urea utilization by rumen microorganisms.
Journal ofAnimal Science 10:683.
Belasco I J. 1956. The role of carbohydrates in urea utilization, cellulose digestion and
fatty acid formation. Journal ofAnimal Science 15:496.
Berger L L, Paterson AJ, Klopfenstein T J and Britton R A. 1979. Effect of harvest date
and chemical treatment on the feeding value of corn stalklage. Journal ofAnimal
Science 49:1312.
Jackson M G. 1978. Treating strawfor animal feeding. FAO Animal Production and
Health Paper 10. FAO (Food and Agriculture Organization of the United Nations),
Rome, Italy.
Kiangi EMI. 1981. Ammonia treatment of low quality roughages to improve their
nutritive value. In: Kategile J A, Said AN and Sundstol F (eds), Utilization of low
quality roughages in Africa. Proceedings of a workshop held at Arusha, Tanzania,
18-22 January 1981. AUN Agricultural Development Report 1. AUN (Agricultural
University of Norway), Aas, Norway. pp. 49—54
Klopfenstein T J. 1978. Chemical treatment of crop residues. Journal ofAnimal Science
46:841.
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Munthali J T. 1987. Cattle fattening on basal diets of maize stover and groundnut tops in
Malawi. In: Little D Aand Said AN (eds), Utilization of agricultural by-products as
livestockfeeds in Africa. Proceedings of a workshop held at Ryall's Hotel, Blantyre,
Malawi, September 1986. ARNAB (African Research Network for Agricultural
By-products). ILCA(International Livestock Centre for Africa), Addis Ababa,
Ethiopia. pp. 45-52.
Munthali J T, Zimba AW C and Kamwanja L A. 1990. Effects of urea treated maize
stover on the performance of lactating crossbred dairy cows. In: Annual Technical
Report, Dairy/BeefProduction Systems (Malawi). University of Malawi and Ministry
of Agriculture, Lilongwe, Malawi.
Pearson R M and Smith JAB. 1943. The utilization of urea in the bovine rumen. e. The
synthesis and breakdown of protein in the rumen ingesta. Biochemical Journal 37:153.
Smith T, Chakanyuka C, Sibanda S and Manyuchi B. 1989. Maize stover as feed for
ruminants. In: Said AN and Dzowela B H (eds), Overcoming constraints to the
efficient utilization ofagricultural by-products as animalfeed. Proceedings of the
Fourth Annual Workshop held at the Institute of Animal Research, Mankon Station,
Bamenda, Cameroon, 20-27 October 1987. ARNAB (African Research Network for
Agricultural By-products). ILCA (International Livestock Centre for Africa), Addis
Ababa, Ethiopia. pp. 218-231.
Sundstol F, Coxworth E and Mowat D N. 1978. Improving the nutritive value of straw
and other low quality roughages by treatment with ammonia. WorldAnimal Review
26:13-21.
286
EFFECTS OF UNDEGRADABLE PROTEIN SUPPLEMENTS ON
THE PERFORMANCE OF WEANER STEERS FED VELD HAY
SPRAYED WITH UREA
S Sibanda1'2, L R Ndlovu2 and TSmith1
Grasslands Research Station
P Bag 3701, Marondera, Zimbabwe
Department of Animal Science
University of Zimbabwe
PO Box MP 167, Mount Pleasant, Harare, Zimbabwe
ABSTRACT
The effects of different sources of undegradable protein supplements
(cottonseed, soybean, meat and bone and blood meals) on the performance of
Hereford x Africander weaner steers (205 kg liveweight) offered veld hay
sprayed with 1% urea were investigated. Supplementation with undegradable
protein increased dry-matter intake of veld hay offered ad libitum by 18%
(P<0.05) and reduced loss of live- and carcass weight in steers offered sub-
maintenance quantities of veld hay, but had little effect on rumen pH and
ammonia concentration, or degradation of veld hay in the rumen. The results
confirm the beneficial effects of supplementing low quality roughages with a
supply of undegradable protein, but suggest that the undegradable protein from
the four supplements studied was of equal value.
RESUME
Effet des sources de proteines non degradables sur les performances de veaux
sevres recevant du Join traite par pulverisation avec de I'uree
L'effet de diverses sources de protéines non degradables (graines de coton, de
soja, farine de viande et d'os etfarine de sang) sur les performances de veaux
sevres de race croisee Hereford x Africander pesant en moyenne 205 kg depoids
vif et recevant du foin de veld traite par pulverisation avec de I' urée al% aete
etudie. La complementation entrainait une augmentation de 18% (P<0,05) de
I' ingestion de matiere seche de veld offerte ad libitum. Ellefreinait en outre la
baisse du poids vifet du poids de la carcasse mime lorsque les quantités de veld
287
offertes etaient inférieures aux niveaux necessaires a I'entretien. Cependant, la
complémentation riavait qu'un ejfet limiie sur lepH et la concentration en
ammoniac du rumen ainsi que sur la degradation du foin de veld dans le rumen,
Ces résultats confirment les avantages de la complémentation defourrages de
qualité mediocre avec des sources de proteines non degradables. lb permettent
de conclure par ailleurs que les quatre sources de proteines evaluées ici sont de
valeur comparable.
INTRODUCTION
The poor performance of ruminants fed low quality roughages is mainly due to a
deficiency of nitrogen which results in low intake and digestibility of dry matter
(Topps, 1972). Protein and non-protein nitrogen supplements may be used to
correct this deficiency (Topps, 1972; Siebert and Hunter, 1982).
One of the problems of supplementing low quality roughages with a single
daily meal of urea is that the urea is rapidly degraded into ammonia in the rumen
(Falvey, 1982). This results in non-synchronised release of ammonia and energy,
leading to poor utilisation of urea for microbial protein synthesis and substrate
fermentation (Satter and Slyter, 1974). This problem may be overcome by using
slow-release forms of non-protein nitrogen (Ferero et al, 1980) but these
alternatives are generally more expensive than urea.
Spraying urea onto poor quality roughages just before feeding has been
suggested as a way of ensuring uniform release of ammonia to rumen microbes
(Hennessy, 1984). Urea supplementation at the rate of 1% seems adequate for
roughages containing 3-4% crude protein (Verma and Jackson, 1984). However,
the optimum level of urea is likely to vary with the type of roughage.
Further improvements in animal performance may be expected when
roughages fed with urea are supplemented with a source of dietary undegradable
protein (UDP) (Kempton et al, 1979; Smith et al, 1980; Mullins et al, 1984). The
magnitude of the response at equal levels of UDP may depend on the quality of
the protein (Petersen and Clanton, 1981).
A study was carried out to determine the effects of different UDP
supplements on the performance of weaner steers fed veld hay sprayed with 1%
urea. A combined supplement containing iso-nitrogenous levels of cottonseed,
soybean and meat and bone meals was also tested in order to determine if these
proteins were complementary.
MATERIALS AND METHODS
Animals and housing
Twelve rumen-cannulated Hereford x Africander steers (average weight 535 kg)
were used to measure the degradation patterns of veld hay. The cannulae (Pigot
288
Maskew (Pvt) Ltd, Bulawayo, Zimbabwe) were made of rubber with an internal
diameter of 8 cm. In addition, 84 Hereford x Africander weaner steers (average
weight 205 kg) were used to measure intake of veld hay and growth response to
protein supplementation.
The steers were housed in individual pens with concrete floors, asbestos
roofing and sides made of wooden rails. Each pen had a permanent food trough
at one end and a water trough at the other. No bedding was provided.
Experimental design, protein supplements and basal diet
The 84 weaner steers were stratified by weight and randomly allocated to two
groups of six animals and six groups of 12 animals. One group of six animals
was used to determine the initial carcass weight, to provide the baseline for the
growth performance assessment. The animals were fasted for 24 hours and
weighed. They were then slaughtered and their carcasses were weighed. Initial
carcass weight was estimated from the regression equation
ICW = 10.36 + 0.452ISLW (RSD = 3.266; R2 = 0.906)
where:
ICW = initial carcass weight (kg)
ISLW = initial starved liveweight (kg)
The other group of six animals, and five of the groups of 12 animals, were
used in the feeding trial. The treatments were:
1. Basal diet of milled veld hay sprayed and mixed with 1% urea just before
feeding (control, six animals)
2. Basal diet plus cottonseed meal supplement (12 animals)
3. Basal diet plus soybean meal supplement (12 animals)
4. Basal diet plus meat and bone meal supplement (12 animals)
5. Basal diet plus bood meal supplement (12 animals)
6. Basal diet plus a combined supplement of cottonseed, soybean and meat
and bone meals (12 animals)
The remaining group of 12 animals was used to measure intake of veld hay
for the six treatments.
The basal diet was prepared by dissolving urea in warm water and spraying
it onto milled (25-mm screen) veld hay just before feeding. Five litres of a 20%
urea solution were sprayed onto 100 kg of hay to give a 1% level of application.
A mechanical mixer fitted with a horizontal auger was used to prepare the feed,
to ensure that the hay and urea were well mixed. Half of the urea solution was
sprayed onto the hay in the mixer, using a watering can fitted with a rose on the
spout, and the mixer was run for 10 minutes. The remainder of the solution was
then added and the mixing repeated.
The composition of the protein supplements (Table 1) was based on
effective degradabilities determined in an earlier experiment (Sibanda, 1989).
289
Table 1. Composition ofprotein supplements offered to weaner steers fed 1%-urea-treated veld
hay
Composition of treatment diets supplemented with
Cottonseed Soybean Meat and Blood Combined
Ingredient meal meal bone meal meal supplements*
As-fed composition of supplements (g/kg)
White maize grain 780 783 815 815 815
Cottonseed meal 143 - - - 29
Soybean meal - 207 - - 120
Meat and bone meal - - KM - 14
Blood meal - - - 30 -
Urea 14.7 - 16 26 7.6
Gypsum (calcium sulphate) 12 - 12 12 11.7
Salt (sodium chloride) 25.1 5 26.5 58.5 1.4
Monocalcium phosphate 25.2 5 26.5 58.5 1.3
Calculated chemical composition
Dry matter (g/kg) 900 905 900 900 935
Rumen degradable protein
(g/kg DM)
131 125 126 131 124
Undegradable protein
(g/kg DM)
49 53 56 51 50
Total crude protein
(g/kg DM)
180 178 182 182 174
Metabolisable energy
12.8 12.8 12.8 12.8 12.8
(MJ/kg)
* Cottonseed, soybean and meat and bone meals
Determination of degradation patterns of veld hay
The 12 rumen-cannulated steers were used in an incomplete (6 x 2) Latin Square
design with two periods of 24 days each and two animals per treatment; the
treatments were the six diets used in the feeding trial. The steers were offered
0 75veld hay sprayed with 1% urea once daily at 'he rate of 36 g DM/kg ' .Animals
on treatments 2 to 6 were also fed 300 g/day of the protein supplement split into
two equal parts and fed at 0800 and 1400 hours. Water was freely available.
After 21 days on each feeding regime the degradation patterns of veld hay were
measured using the nylon-bag technique (Mehrez and 0rskov, 1977; 0rskov and
McDonald, 1979). Six bags containing veld hay samples (2.5-mm screen) were
incubated in the rumen and one bag at a time was withdrawn after 12, 24, 36, 48,
60 and 72 hours. The constants of the degradation curve (p = a + b(l -e-0')) were
determined according to Mehrez and 0rskov (1977).
290
Rumen liquor samples were taken after all the bags had been withdrawn,
two hours after offering the morning supplement. The contents of the rumen
were mixed by hand before a 200 ml sample was taken with a beaker. The rumen
liquor was strained through four layers of cheesecloth.
Measurement of intake of veld hay
The 12 steers allocated to the intake measurement group were paired in such a
way that animals with weights as similar as possible were placed in one cell.
Intake of veld hay was measured for each of the treatments in an incomplete
(6 x 3) Latin Square design with three four-week periods.
The animals were. fed individually for a preliminary period of three weeks,
followed by a period of seven days when intake was measured. Veld hay sprayed
with 1% urea was offered ad libitum (15% more hay than the previous day's
intake) on a daily basis, with the previous day's refusals being weighed, recorded
and removed before fresh hay was offered. The protein supplements were offered
in two equal meals of 150 g at 0800 and 1400 hours. Water was freely available.
Performance of weaner steers fed veld hay and protein supplements
The feeding trial lasted 90 days. The animals were housed in individual pens and
fed the basal diet (veld hay (sprayed with 1% urea) at the rate of 36 g DM/kg0'75)
once a day in the morning. The protein supplements were offered in two equal
meals at 0800 and 1400 hours at the rate of 300 g/head per day. The animals
were weighed weekly and the allowance of veld hay adjusted if necessary. Water
was freely available. After 90 days the animals were fasted for 24 hours and
weighed. They were then slaughtered and their carcasses were weighed.
Laboratory analyses
The dry-matter content of veld hay and protein supplements was determined by
drying in a forced draught oven at 100°C for 24 hours. Nitrogen was determined
by a macro-Kjeldahl technique.
The pH of the rumen liquor was measured within 10 minutes of sampling.
For rumen ammonia determination, a mixture of 50 ml rumen liquor, 200 ml
water and 100 ml 50% NaOH was distilled and the distillate collected over 2%
boric acid. Released ammonium ion was titrated against 0.1 M HQ using
screened methyl red indicator.
Statistical analysis
Analyses of variance for the degradation curve constants of veld hay and the
protein meals and intake of veld hay were done with the MTNTTAB statistical
291
package. Analyses of variance of live- and carcass weights, with initial starved
liveweight as a covariate, were carried out using the GENSTAT programme. In
all cases differences between treatments were determined by Student's t-test.
RESULTS
Degradation of veld hay
The crude-protein content of the veld hay before and after spraying with 1% urea
was 49 and 73 g/kg DM, respectively. Veld hay degradation constants, rumen pH
and ammonia concentrations did not differ (P>0.05) between any of the
treatment groups (Table 2).
Hay dry-matter intake
Intake of veld hay dry matter by steers fed the basal diet ad libitum is shown in
Table 3. Steers fed the protein supplements ate 18% (P<0.05) more hay than the
steers fed no supplement. However, differences among the supplemented groups
were not significant (P>0.05).
Degradation constants for
veld hay*
Rumen ammonia
Treatment a b c
Rumen pHb (mg/litre)b
1. Basal diet (C): milled veld hay
treated with 1% urea
103 75.4 0.016 7.2 309
2. (C) + cottonseed meal 11.1 71.8 0.011 7.1 339
3. (C) + soybean meal 7.0 72.7 0.025 7.4 301
4. (C) + meat and bone meal 10.3 76.4 0.010 7.1 336
5. (C) -I- bood meal 7.0 63.7 0.015 7.1 293
6. (C) + combined supplementc 8.4 60.2 0.012 7.2 306
SE Z65 15.80 0.0083 0.16 62.0
Table 2. Degradation constants for veld hay dry matter and rumen pH and ammonia
concentration in steersfed lib-urea-treated veld hay (36 g DMIkg ' per day) with or
withoutprotein supplements
* From the equation p = a + t^l-e"*)
where:
p = dry-matter loss (%)
a = readily degradable fraction (%)
b = potentially degradable fraction (%)
c = rate of degradation of the b fraction
t = time (hours)
Rumen liquor samples were taken 2 hours after offering the morning supplement
c Cottonseed, soybean and meat and bone meals
292
Table 3. Intake ofveld hay dry matter by weaner steers fed 1%-urea-treated veld hay id libitum
with or without protein supplements
Treatment
Intake of veld hay dry matter
(g/kg°-75perciay)
1. Basal diet (C): milled veld hay treated with 1% urea
2. (C) + cottonseed meal
3. (C) + soybean meal
4. (C) + meat and bone meal
5. (C) + bood meal
6. (C) + combined supplement'
SE
52.1
(OS
61.1
65.4
61.5
66.1
2.87
* Cottonseed, soybean and meat and bone meals
Live- and carcass weight changes of steers on restricted hay intake
The live- and carcass weight changes of steers fed restricted amounts of veld hay
sprayed with urea (36
are shown in Table 4.
g DM/kg ' j and offered different protein supplements
All steers lost live- and carcass weight. Steers fed the combined supplement
lost 8.8 kg more (P<0.05) liveweight than the steers offered other supplements,
but this was not significantly different to the performance of the control steers.
The steers in the other supplemented groups lost similar amounts of liveweight
but only the steers fed cottonseed meal performed better (P<0.05) than the
control steers.
2. (C) + cottonseed meal 196.2 1627 -33.5 98.9 79.9 -19.0
3. (C) + soybean meal 195.8 161.7 -34.1 98.9 80.6 -18.3
4. (C) + meat and bone meal 195.4 160.0 -35.4 98.9 80.8 -18.1
5. (C) + bood meal 195.4 160.4 -35.0 98.9 78.9 -20.0
6. (C) + combined supplement* 199.2 155.9 -43.3 98.9 77.4 -21.4
SE 6.60 2.53 2.53 0.01 1.41 1.40
Table 4. Live- and carcass weight changes ofweaner steers fed 1%-urea-treated veld hay (36 g
DMIkg ' per day) with or withoutprotein supplements
Starved liveweight (kg) Carcass weight (kg)
Treatment Initial Final Change Initial Final Change
1. Basal diet (C): milled veld hay
treated with 1% urea
190.8 151.5 ^39.3 98.9 72.5 -26.4
* Cottonseed, soybean and meat and bone meals
293
The steers in the control group lost 7 kg more (P<0.05) carcass weight than
the steers fed supplements. Among the supplemented steers the only significant
(P<0.05) difference was between the steers fed the combined supplement and
those fed soybean and meat and bone meal supplements.
DISCUSSION
Protein source had no significant effect (P>0.05) on the extent and rate of
degradation of veld hay in the rumen of steers on the different treatments. This
indicates that the rumen environments in the steers on the different treatments
were similar. The rumen pH and ammonia concentrations confirm this view.
Preston and Leng (1987) have recommended rumen ammonia concentrations of
at least 150 mg/litre for roughages of similar quality to the hay used in this
experiment. The concentrations recorded in this experiment were more than
double this recommended figure. However, only one sample was taken, and
sampling could have coincided with peak concentrations.
The absence of a significant effect of protein supplementation on the
degradation of veld hay suggests that the basal diet supplied adequate nutrients
for the rumen microbes and that the supply of pre-formed amino acids, peptides
and carbon chains from protein nitrogen sources provided no added advantage.
Other studies (Kellaway and Leibholz, 1983; Sriskandarajah and Kellaway,
1984; Ndlovu, 1985) have found that when rumen ammonia concentrations are
adequate the response to rumen degradable protein from protein nitrogen sources
is negligible. Thus, while acknowledging diurnal variation and the fact that spot
samples were used, it may be inferred that the ammonia concentrations found in
this experiment were adequate for both maximum microbial protein production
and optimum degradation of veld hay.
Although there was no increase in the rate or extent of degradation of veld
hay with protein supplements, there was a significant (P<0.05) increase in intake
of veld hay dry matter. Kempton et al (1979) obtained similar results. Since the
degradation of veld hay was similar in all treatments, it may be inferred that the
increase in veld hay intake was not due to an improvement in the rumen
environment of the supplemented animals compared to the control ones.
Supplementation with protein, in addition to urea sprayed on the veld hay,
resulted in a significant (P<0.05) reduction in live- and carcass weight losses in
weaner steers offered sub-maintenance amounts of veld hay. This suggests that
the effects of protein supplementation were achieved not only through an
increase in roughage intake, but also through an improvement in nutrient supply.
This agrees with the findings of Smith et al (1978) and Ortigues (1987) who
offered fish meal to growing dairy heifers and steers fed restricted amounts of
fibre-rich diets, although their animals were fed in excess of maintenance
requirements.
However, the reduction in live- and carcass weight losses with protein
supplemented treatments compared to the control may be partly explained by an
294
increase in energy intake. Assuming a metabolisable energy (ME) content of
6.72 MJ/kg DM for veld hay (Topps and Oliver, 1978), an intake of 36 g of veld
nay DM/kg0-75 would be equivalent to about 0.242 MJ ME/kg0.75. Taking a steer
of about 178 kg liveweight (mean of the initial and final weights), the 300 g/day
of supplement translates to 6.2 g/kg0.75, equivalent to 0.079 MJ ME/kg075. This
level of supplementation is equivalent to an increase of about 33% in ME intake.
The average improvement in carcass weight change with supplementation was
about 27%.
While the contribution of ME intake in reducing live- and carcass weight
losses of the supplemented steers is acknowledged, it is possible that part of the
response was due to UDP (undegradable protein) supply. Several studies (Smith,
1978; Lindsay and Loxton, 1981; Fattet et al, 1984; Ortigues, 1987) have shown
the beneficial effects of UDP supplementation compared to energy at equal ME
intakes. Smith (1978) used multiple regression analysis to show that for diets
with high roughage and low protein content (85 g CP/kg DM), as used in this
experiment, ME and UDP intake accounted for about 10 and 25%, respectively,
of the total variation in liveweight gains of growing dairy heifers and steers.
The metabolisability (ME/GE) of the diet used in the current experiment
was estimated to be about 0.42. This would give a km value of 65% (ARC,
1980). Therefore the contribution of increased energy intake to the reduction in
carcass weight loss in this experiment would be about 79% of the total response
to supplementation. The remainder would be due to UDP supply.
The reason for including the combined protein supplement was to determine
if the individual protein sources would complement each other and result in
improved performance. There was no evidence of this for either veld hay intake
or live- or carcass weight changes of steers. In fact, there was a slight negative
response to the combined supplement compared to the individual protein sources.
The lack of difference in the degradation and intake of veld hay and,
possibly, in the performance of weaner steers fed restricted quantities of veld hay
and offered different protein supplements, supports the observations by Oldham
(1981) and 0rskov (1982) that there is little likelihood of improving animal
performance by manipulating the quality of protein supply to the animal. This is
because the amino acid composition of digesta passing into the duodenum was
found to vary little under different feeding conditions (Oldham, 1981).
CONCLUSIONS
This study confirms the positive effects of UDP supplementation, in addition to
adequate rumen degradable protein, on the performance of growing steers
offered restricted quantities of low-protein roughages. The feeding of protein
supplements led to an increase in intake of low-protein veld hay irrespective of
protein source. However, the source of UDP had no effect on either intake or the
performance of steers, suggesting that the UDP from the four proteins was of
equal value.
295
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ARC (Agricultural Research Council). 1980. The nutrient requirements ofruminant
livestock. Commonwealth Agricultural Bureaux, Slough, UK. 351 pp.
Fattet I, Hovell F D DeB, 0rskov E R, Kyle D J, Pennie K and Smart R 1. 1984.
Undernutrition in sheep. The effect of supplementation with protein on protein
accretion. British Journal ofNutrition 52:561-574.
Falvey J L. 1982. The effect of infrequent administration of urea on rumen ammonia and
serum level of cattle consuming rice straw. TropicalAnimalProduction 7:209-212.
Ferero O, Owens F N and Lusby K S. 1980. Evaluation of slow-release urea for winter
supplementation of lactating range cows. Journal ofAnimal Science 50:532-538.
Hennessy D W. 1984. Response of cattle on low quality pasture to increments of urea or
to a supplement of protein. Proceedings oftheAustralian Society ofAnimal
Production 15:388-391.
Kellaway R C and Leibhclz J. 1983. Effects of nitrogen supplements on intake and
utilization of low quality roughages. WorldAnimalReview 48:33-37.
Kempton T J, Nolan J V and Leng R A. 1979. Protein nutrition of growing lambs. 1.
Responses in growth and rumen function to supplementation of a low-protein-
cellulosic diet with either urea, casein or formaldehyde treated casein. British Journal
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Lindsay J A and Loxton I D. 1981 . Supplementation of tropical forage diets with protected
proteins. In: Farrell D J (ed), Recent advances in animal nutrition. University of New
England, Armidale, New South Wales, Australia. p. 1A.
Mehrez AZ and 0rskov E R. 1977. A study of the artificial fibre bag technique for
determining the digestibility of feeds in the rumen. Journal ofAgricultural Science,
Cambridge 88:645-650.
Mullins T J, Lindsay J A Kempton T J and Toleman M A. 1984. The effects of three
different nitrogen based supplements on the utilization of tropical forage diets by zebu
crossbred steers. Proceedings of the Australian Society ofAnimalProduction
15:487-489.
Ndlovu L R. 1985. Alfalfa supplementation ofpoor quality roughagesfed to sheep. PhD
Thesis. University of Guelph, Ontario, Canada. 153 pp.
Oldham J D. 1981. Amino acid requirements for lactation in high-yielding dairy cows. In:
Haresign W and Cole D J A(eds), Recent developments in ruminant nutrition.
Butterworths, London, UK. pp. 49-81.
Orskov E R. 1982. Protein nutrition in ruminants. Academic Press, London, UK and
New York, USA. 160 pp.
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from incubation measurements weighted according to rate of passage. Journal of
Agricultural Science, Cambridge 92:499-503.
Ortigues I. 1987. Nutrient supply, growth and calorimetric efficiency in heifers offered
straw rich diets. PhD Thesis. University of Reading, Reading, UK. 208 pp.
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Petersen M K and Clanton D C. 1981. Bypass protein (blood meal) in winter range
supplements for the grazing beef cow and weaned calf. Proceedings ofAmerican
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Preston T R and Leng R A. 1987. Matching ruminant production systems with available
resources in the tropics and subtropics. Penambul Books, Armidale, New South
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protein production in vitro. British Journal ofNutrition 32:194-208.
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University of Reading, Reading, UK. 198 pp.
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pp. 414-^30.
297
298
EFFECTS OF SUPPLEMENTING ALOW QUALITY FORAGE
WITH CONCENTRATES ON PERFORMANCEAND SEXUAL
DEVELOPMENT OF DAIRY HEIFERS
A E El-Tayeb, TA Mohammed, AMHomeida andA A Mohammed
Department of Animal Nutrition
Institute of Animal Production
University of Khartoum
PO Box 32, Khartoum North, Sudan
ABSTRACT
Afeeding trial was conducted with crossbred dairy heifers to examine the effects
on animal performance and sexual development of supplementing green
Sorghum bicolor with low or high levels of concentrate. Supplementation had
highly significant (P<0.01) effects on average daily gain, feed conversion
efficiency and heart girth of experimental animals. Animals supplemented with
the high level of concentrate reached puberty significantly (P<0.05) younger and
at heavier liveweight than those on the low level of concentrate. Heifers fed
forage only did not reach puberty during the experimental period.
RESUME
Performances et développement sexuel de génisses de race laitiere alimentées
avec unfourrage de qualité médiocre compléments avec des concentrés
Un essai d'alimentation a eté effectué sur des génisses metisses de race laitiere
pour examiner I'effet, sur leurs performances et leur developpement sexuel, de la
complementation de fourrage vert de Sorghum bicolor avec deux niveaux de
concentrés. La complementation avait un effet hautement significatif(P<0,01)
sur les gains moyens quotidiens, le taux de conversion des aliments et le
périmètre thoracique des animaux. Les génisses recevant le niveau élevé de
concentrés avaient atteint la puberté à un âge significativement (P<0,05)
inférieur et à un poids vifsupérieur à celui des sujets soumis au faible niveau de
concentré. Enfin, aucune des génisses recevant uniquement du fourrage n'avait
atteint la puberté au cours de la période expérimentale.
299
INTRODUCTION
Sorghum bicolor is a popular ruminant feed in Sudan. However, because its
digestible crude-protein content is low, animals fed only this forage do not
perform well. Supplementing forage-based diets with concentrates can improve
rumen fermentation, fibre digestibility and forage intake (Church and Santos,
1981; Lee et al, 1985; McCollum and Galyean, 1985). El-Tayeb and Gaber
(1987) demonstrated that supplementing a combination of forages with
concentrates improves performance and reproductive traits of Sudanese
crossbred dairy heifers. However, during much of the year only one forage may
be available. Therefore, the objective of this research was to examine the
performance and sexual development of dairy heifers fed a low-quality forage
(Sorghum bicolor) supplemented with a concentrate mixture.
MATERIALAND METHODS
Eighteen crossbred (Butana x Friesian) dairy heifers (average liveweight
approximately 100 kg) were used in this trial; they were selected at random from
a large herd which was housed and treated as one group. The animals were
allowed a seven-day adaptation period after which they were stratified according
to liveweights into three similar groups, of six animals each, which were then
randomly assigned to one to the following treatments:
• forage only (diet A)
forage plus 1 kg concentrate mixture (diet B)
• forage plus 2 kg concentrate mixture (diet C).
Heifers were penned and fed in pairs.
The concentrate mixture comprised 35% sorghum grain, 35% sunflower
cake, 27% wheat bran, 2% limestone flour and 1% common salt.
For the first 130 days of the trial Sorghum bicolor was the only forage
offered to the experimental animals. For the next 45 days sorghum was in short
supply and the heifers were fed a mixture of groundnut hulls, alfalfa and
sorghum. Sorghum then became freely available again and was offered to the
heifers until they reached puberty.
The chemical analysis of the feed ingredients is shown in Table 1.
The concentrate was offered to the heifers once a day at 0800 hours
throughout the experimental period. The heifers ate all the concentrate offered.
Clean water was available throughout the experimental period in all pens.
The daily allowance of the forage was offered in one meal at 1000 hours,
the amount offered being adjusted daily until the refusals were about 10% of the
amount offered. Forage refusals were collected the following morning and the
weight recorded. The daily feed intake was then calculated by subtracting the
refusals from the amounts offered.
The heifers were weighed, and their heart girths measured, every two weeks
at 0700 hours before the morning meal. Average daily gain of the heifers was
300
Table 1. Chemical composition ofingredients oftreatment diets
Compositioni (% DM)
Concentrate Sorghum Groundnut
mixture bicolor hulls Alfalfa
Dry matter (DM) 98.4 94.3 97.0 93.6
Ash 6.2 8.2 6.5 10.6
Crude protein (CP) 20.8 4.1 5.8 16.8
Crude fibre (CF) 33.4 39.3 66.5 28.0
Ether extract (EE) 6.3 1.8 2.7 21
Nitrogen-free extract (NFE) 31.5 45.0 18.4 36.1
ME, Ml/kg DM 10.52 9.31 7.43 9.12
Chemical compositions were determined by methods described by AOAC (1980)
Metabolisable energy (ME) values were obtained using the following equation (Ellis, 1980):
ME (MJ/kg DM) = 0.012CP + 0.031EE + 0.005CF + 0.014NFE
calculated by dividing the average biweekly liveweight gain by 14. Feed
conversion ratio (kg feed/kg weight gain) was also computed.
Sexual maturity was detected by the first presence of progesterone in the
peripheral blood of the heifers. Jugular venous blood (5 ml) was obtained from
each heifer once a week during the experimental period, by direct venipuncture
using 22G needles. Serum progesterone was assayed by direct solid-phase
radioimmunoassay.
Data were subjected to analysis of variance applicable to the randomised
complete-block design (Steel and Torrie, 1980). Differences among treatment
means were determined by least significant differences (Steel and Torrie, 1980).
RESULTS AND DISCUSSION
There were no significant differences (P>0.05) in dry-matter intake across
treatments (Table 2). This finding agrees with that of Tayler and Wilkison
(1972), but contradicts other studies which indicated that roughage intakes were
depressed by increasing the level of concentrate supplementation (McCullough,
1970; Leaver, 1973).
As expected, metabolisable energy and crude-protein intakes increased
(P<0.01) as the level of concentrate supplement was increased (Table 2).
There were highly significant (P<0.01) differences in the final liveweights,
average daily gains and feed conversion ratios of heifers in the three treatment
groups (Table 3). The weight improvement in heifers fed concentrates was
expected, as the concentrate would provide nutrients which may be lacking or
deficient in the forage. Previous studies (Tayler and Wilkison, 1972; Leaver,
1973; El-Tayeb and Gaber, 1987) also found that liveweight gain increased as
301
Table 2. Effect ofconcentrate supplements on feed intake ofdairy heifers over 130 days
Dry-matter intake (kg)
Diet A DietB DietC
Sorghum bicolor 3.33 3.17 3.02
Concentrate - 0.98 1.96
Total 3.33 4.15 4.98
Daily dry-matter intake
(% of liveweight)
252 2.59 2.55
Daily ME intake (MI) 31.00a 39.83b 48.73c
Daily crude-protein intake M) 0.14a 0.33b 0.52c
Means in the same row followed by a different letter differ significantly (P<0.01)
Table 3. Effect ofconcentrate supplements on liveweight gain andfeed efficiency ofdairy heifers
over 130 days
DietA DietB DietC
Initial liveweight (kg) 100.0 99.8 100.2
Final liveweight (kg) 119.8a 160.8b 195.7c
Average daily gain (kg) 0.15a 0.47b 0.74c
Feed conversion ratio
(kg feed/kg weight gain)
19.8a 8.9b 6.8c
Means in the same row followed by a different letter differ significantly (P<0.01)
the rate of concentrate supplementation increased. The feed conversion ratios
found in the present study were higher than those observed by El-Tayeb and
Gaber (1987); this discrepancy may be due to the roughage used, which directly
affects the dry-matter intake and hence feed conversion ratio.
The relationship between liveweight and heart girth is shown in Table 4.
The greater (P<0.01) increase in heart girth was achieved by animals on the high
level of supplementation. Shioya et al (1975) and Takla (1988) also found that
concentrate supplementation had a highly significant effect on heart girth.
Serum progesterone was not detected in heifers in group A (the
unsupplemented heifers), or in two heifers in group B. Serum progesterone
concentrations of the remaining heifers are shown in Table 5. These data are in
line with those reported by Donaldson el al (1970) who found that the plasma
progesterone concentrations of heifers ranged from 0.3 to 3.9 ng/ml when the
first sample was obtained.
Ovary surface examination by rectal palpation showed that high
concentrations of progesterone were accompanied by the presence of corpus
luteum. This agrees with previous work by Rakha et al (1970).
302
Table 4. Effect ofconcentrate supplements on body conformation ofdairy heifers
Diet A DietB DietC
Initial
Liveweight (kg)
Heart girth (cm)
Correlation coefficient
Final
Liveweight (kg)
Heart girth (cm)
Correlation coefficient
100.0 99.8 100.2
112 112 111
0.99 0.99 0.97
119.8a 160.8b 195.7c
136a 187b 219c
0.98 0.98 0.97
Means in the same row followed by a different letter differ significantly (P<0.01)
Table 5. Serum progesterone concentration ofdairy heifers
Serum progesterone concentration (ng/ml) for individual heifers
DietB DietC
IstDs 0.77 278 0.94 221 0.89 221 3.35 1.08 0.87 0.94
2ndDs 1.89 0.40 3.92 0.48 1.75 0.48 0.54 1.98 1.53 3.40
3rdDs 3.21 0.98 0.44 0.64 3.45 0.64 ND 3.47 2.20 ND
4th Ds 0.42 3.12 0.82 1.74 ND 1.74 ND 0.67 0.60 0.91
5th Ds 0.69 ND 1.68 3.27 0.98 3.27 0.69 1.20 0.93 1.63
* All heifers in group A, and two heifers in group B, did not reach puberty
Ds = Detectable sample
ND = Non-detectable
Some heifers showed visible signs of oestrus before progesterone was
detected in their peripheral blood.
Heifers fed the high level of concentrate reached puberty (first onset of
oestrus) at a significantly (P<0.05) younger age (20.5 months) and heavier
liveweight (248 kg) than heifers fed the low level of concentrate (23.9 months
and 231 kg, respectively). Generally, these findings agree with those of previous
studies (Rakha et al, 1970; Short and Bellows, 1971; Little and Kay, 1979;
Stewart et al, 1980; El-Tayeb and Gaber, 1987) which showed that the improved
nutrition affected the onset of puberty in cattle.
The relationship between age and liveweight at puberty (r=0.33) was
positive, but not significant (P>0.05), indicating that animals reached puberty at
a given liveweight rather than at a given age.
303
CONCLUSIONS
This work demonstrates that supplementing poor quality forage improves the
performance and reproductive traits of crossbred dairy heifers. More research is
needed to examine the influence of different types of supplement and
combinations of forages, and to determine the optimum level of supplementation.
REFERENCES
AOAC (Association of Official Analytical Chemists). 1980. Official method of analysis.
13th edition. AOAC, Washington, DC, USA 1018 pp.
Church D C and Santos A 1981. Effect of graded levels of soybean meal and of a
nonprotein nitrogen-molasses supplement on consumption and digestibility of wheat
straw. Journal ofAnimal Science 53:1609-1615.
Donaldson L E, Basset J M and Thorburn G D. 1970. Peripheral plasma progesterone
concentration of cows during puberty, oestrous cycle, pregnancy and lactation and the
effect of undernutrition or exogenous oxytocin on progesterone concentration Journal
ofEndocrinology 48:599.
Ellis N. 1980. The nutrient composition ofSudanese animalfeeds. Bui I. Northern and
Central Sudan. Animal Nutrition Research Laboratory, Kuku, Khartoum North.
Appendix 1, p. 19.
El-Tayeb A E and Gaber S S. 1987. Effects of concentrate supplements to forages on some
production traits of dairy heifers. Sudan Journal of Veterinary Science andAnimal
Husbandry 27:70-77.
Leaver J D. 1973. Rearing of dairy cattle. 4. Effect of concentrate supplementation on the
live weight gain and food intake of calves offered roughages ad libitum. Animal
Production 17:43-52.
Lee G L, Hennessy D W, Williamson P J, Nolan J V, Kempton R J and Leng R A. 1985.
Responses to protein meal supplements by lactating beef cattle given a low quality
pasture hay. Australian Journal ofAgricultural Research 36:729.
Little W and Kay R M. 1979. The effect of rapid rearing and early calving on the
subsequent performance of heifers. Animal Production 29:131-142.
McCollum F T and Galyean M L. 1985. Influence of cottonseed meal supplementation on
voluntary intake, rumen fermentation and rate of passage. Journal ofAnimal Science
60:570-577.
McCullough TA 1970. A study of the effect of supplementing a concentrate diet with
roughages of different quality on performance of Friesian steers. Journal of
Agricultural Science, Cambridge 75:327-335.
Rakha A M, Hale D and Igboeli G. 1970. The age at puberty in local breeds of cattle in
Central Africa. Journal ofReproduction and Fertility 22:369.
304
Shioya Y, Obata T and Fukuhara R. 1975. Growth and growth patterns of Japanese cattle
on pasture. 3. Relationship of body measurements with body-weight in growing
female calves. Animal Breeding Abstracts 43:448.
Short R E and Bellows R A. 1971. Relationships among weight gains, age at puberty and
reproductive performance in heifers. Journal ofAnimal Science 32: 127-131.
Steel R G D and Torrie J H. 1980. Principles andprocedures ofstatistics. A biometrical
approach. 2nd edition. McGraw-Hill, New York, USA. 633 pp.
Stewart T S, Long C R and Cartwright T C. 1980. Characterization of cattle of a
five-breed diallel. 3 Puberty in bulls and heifers. Journal ofAnimal Science 50:808.
Takla A G. 1988. Effect of level offeeding Holstein-Friesian heifers in late pregnancy on
first lactation performance. MSc Thesis. University of Khartoum, Khartoum, Sudan.
pp. 35^6.
Tayler J C and Wilkison J M. 1972. The influence of level of concentrate feeding on the
voluntary intake of grass and on live weight gain by cattle. AnimalProduction
14:85-96.
305
306
INTEGRATED FEED RESOURCE USE ON FARM

PROSPECTS FOR INTEGRATING FOOD AND FEED
PRODUCTION IN WELAYITA SODO, ETHIOPIA
Adugna Tolera andA N Saicr
1Awassa College of Agriculture
Addis Ababa University
PO Box 5, Awassa, Ethiopia
International Livestock Centre for Africa (ILCA)
PO Box 5689, Addis Ababa, Ethiopia
ABSTRACT
Welayita Sodo is a densely populated and intensively cultivated mid-altitude area
of Ethiopia. Smallholder mixed farming is the dominant mode of production.
The crop and livestock subsystems are closely interdependent: livestock
contribute to the cropping system in the form of draught power, manure and
sources of cash for purchase of crop production inputs, while crop residues
provide livestock feed, especially during the dry season.
Because of the high population density, land holdings per household are
small. Inadequate feed supply is the main constraint to livestock production. In
order to optimise overall productivity there is a need to integrate food and feed
production. Introducing forage legumes seems an acceptable approach: forage
legumes will improve soil fertility, crop yields and herbage quality, and make the
system more sustainable. Hedgerows of multipurpose fodder trees, productive
backyard forages and undersowing or interplanting improved forages with food
or plantation crops will probably be the most successful forage development
strategies in this area. Research should look at temporal interactions between
forage supply and form of feeding and nutrient demand by animals to exploit
opportunities for marketing animals and their products.
RESUME
Perspectives de I integration des cultures vivrieres et de la production des
aliments du betail a Wolayita Sodo (Ethiopie)
Wolayita Sodo est une région d' altitude moyenne, densément peuplée, oil
I'agriculture constitue une activité extremement répandue dominéepar le
309
systime de la petite exploitation mixte. L'élevage y est étroitement associé à
I'agriculture: d'une part, le betail fournit I'énergie de traction et le fumier et
assure des revenus monétaires servant à I'achat des intrants agricoles; de
I'autre, les résidus de récolte entrent dans l'alimentation des animaux,
notamment au cours de la saison seche.
Compte tenu de la forte densité depopulation de cette région, les ménages
doivent se contenter de petits lopins de terres. Par ailleurs, les pénuries
d'aliments du betail constituent ici le principal obstacle au développement de
I'élevage. Pour optimiser la productivite de I'ensemble du système, il convient de
promouvoir I'intigration de la production des cultures vivrières et des aliments
du betail. L'introduction de legumineuses fourrageres dans ces systèmes de la
petite exploitation mixte semble constituer une stratigie viable. En effet, celles-ci
permettront, non seulement d'améliorer la fertilité des sols, les rendements des
cultures et la qualite du couvert herbacé, mais également depromouvoir la
durabilite du système. La mise en place de haies de ligneuxfourragers à usages
multiples et de vergers d'embouche ainsi que l'introduction d'especes
fourrageres améliorées sous culture ou entre les rangées déplantes vivrieres ou
pérennes constituent sans doute certaines des meilleures strategies possibles
dans cette région. Enfin, il convient, pourpromouvoir la commercialisation du
bétail et des productions animales, d'effectuer une étude approfondie des
interactions à long terme, entre d'une part les disponibilites fourrageres et de
I'autre, le mode d'alimentation et les besoins en élements nutritifs des animaux.
INTRODUCTION
Adiagnostic survey was carried out in 1988 to assess the feed resources and the
animal production situation in Welayita Sodo, Ethiopia. Data were collected by
interviewing 102 heads of households in the study area. In addition to the formal
survey, supplementary information was collected from the Ministry of
Agriculture. The information reported in this paper is partly based on this survey.
Welayita Sodo is located at 6° 49' N latitude and 39° 47' E longitude, about
400 km south-west of Addis Ababa at an altitude of about 1900 m. The area has
moderately drained, acidic red soils (nitosols). The average monthly temperature
in the area ranges between 11.9°C (August) and 26.2°C (January) with a mean
annual temperature of 18.9°C. Rainfall averages 1100 mm a year and is bimodal,
with the short rains from February or March until April and the long rains from
June until September or October. The area is representative of medium altitude,
medium rainfall, acid soil areas of western Ethiopia, Kenya, Tanzania, Uganda,
Rwanda, Burundi and Cameroon.
The population density at Welayita Sodo is 250 inhabitants per km2, similar
to that of other densely populated areas in Ethiopia. Land holdings are very
small, the average per household being 0.96 ha. More than 65% of the total
holding is cultivated, of which 68% is under food crops. Cash crops occupy 32%
while cultivated forages occupy only 0.04% of the cultivated land.
310
The cropping system of the area is very intensive. Major food crops include,
in order of importance, maize, sweet potato, enset (false banana), teff (Eragrostis
tef), haricot bean, taro, sorghum, Irish potato, yam and cassava. Coffee is the
major cash crop. Intercropping is a common practice. Some farmers use
chemical fertiliser, mainly diammonium phosphate, on food crops such as teff
and maize.
About 93% of the farmers are engaged in livestock production in addition to
cropping. The average livestock holding per household is 3.60 cattle, 0.74 sheep,
0.25 goats, 0.13 donkeys, 0.02 mules, 0.02 horses and 2.09 poultry. The
predominant breed of cattle is the local zebu.
Animal manure is applied on garden crops; livestock also provide draught
power for important farm operations. Crop residues are mainly used as
dry-season feed for livestock. It seems that there is a strong positive interaction
between crop and livestock production. This paper, therefore, attempts to assess
this complementarity and the prospects for further integration of food and feed
production in Welayita Sodo.
PREVAILING FEED RESOURCES IN WELAYITA SODO
Type and nutritional quality of available feed resources
Natural pasture is the main source of feed for most of the year, but because of
population pressure grazing land is limited to about 0.23 ha/household. Some
65% of the respondents do not have access to common grazing land and so have
to depend on their small individual holdings. About 50% of the farmers buy-in
additional grass from outside their farm.
Quantitatively, therefore, stubble grazing and crop residues also serve as
important sources of feed. Cereal crop residues (straws and stovers) are mostly
stacked and fed to livestock during the dry season when the quantity and quality
of available fodder from natural pasture declines drastically.
The use of concentrate feeds is very minimal or nonexistent. However,
malted barley and boiled maize are occasionally fed to lactating cows to
stimulate milk production. Agro-industrial byproducts such as meat and bone
meal, oilseed cakes and flour mill byproducts are not available in the area.
Two mineral-rich soils, locally known as Bole and Megadua are used as
mineral supplements for ruminants and equines, respectively.
Farmers also lop the leaves and branches of various trees and shrubs and
feed them to their animals during the dry season. They also collect herbaceous
wild plants, mostly legumes, as feed for lactating cows. Specimens of these
plants were collected and identified at ILCA They include Acacia spp, Albizia
spp, Buddleja polystachya, Clausena anisata, Combretum spp, Cordia
abyssinica, Dodonaea viscosa, Dracaena steudneri, Ehretia cymosa, Erythrina
brucei, Flacovirtia indica, Grewia spp, Ipomoea spp, Neonotonia wightii, Olea
311
africana, Rubia cordifoliu, Schrebera alata, Triumfetta rhomboidea, Vernonia
amygdalina, Zornia glochidiata and Zornia setosa. Enset and cassava leaves and
sweet potato vines are also fed to animals during the dry season.
The chemical composition and in vitro dry-matter (DM) digestibility of
some of these feeds were determined. Crude-protein (CP) content ranged from
3.38% (sweet potato tuber) to 24.19% (cassava tops). Neutral detergent fibre
(NDF) content ranged from 31.28% (Dracaena steudneri) to 62.20% (sorghum
leaves). Acid detergent fibre (ADF) content varied between 6.73% (sweet potato
tuber) and 56.85% (Cordia abyssinica). Lignin content ranged from 1.35%
(sweet potato tuber) to 27.86% (Cordia abyssinica). The ADF-ash content,
which is indicative of the silica content, ranged from 0% in some of the feeds to
17.13% in Combretum sp. In vitro DM digestibility varied between 32.90 and
82.17% and was negatively correlated with ADF (r=-0.71) and lignin (r=-0.60)
contents. About 74% of the feeds commonly used had in vitro DM digestibility
values greater than 50%.
All the feeds analysed, with the exceptions of sweet potato tuber, Schrebera
alata and sorghum leaves, had relatively high CP content—above the 7.5%
considered necessary for optimum rumen function. Thus, most of them could be
useful supplements to diets based on crop residues and poor quality natural
pastures, which have low protein content.
Most of the feeds analysed contained adequate amounts of all the required
minerals, with the exception of phosphorus and sodium. Bole and Megadua soils
are rich in sodium, and could be used as sources of the mineral, but are low in
phosphorus. Moreover, the high calcium content in the various feeds and mineral
soils could aggravate the wide Ca:P ratio and precipitate the problem of
phosphorus deficiency. Attempts should be made to correct the phosphorus
levels of these feeds when they are used as dry-season supplements to diets
based on crop residues and dry pastures.
Availability of feed resources in Welayita district
Estimated quantities offeed resources
The total quantities of feed obtainable from crop residues in 1982/83 and
1983/84 are shown in Table 1; there was drought in in Welayita Sodo in 1983/84.
Assuming 10% wastage, the quantity potentially available for actual animal
consumption was estimated as almost 166 000 and 107 000 t of DM in 1982/83
and 1983/84, respectively. Among the many types of crop residue, maize stover
and enset are quantitatively the most important, followed by teff, sorghum,
haricot bean and sweet potato.
In addition, natural sources provide more than 475 000 t of feed dry matter
per year, about 73% of which is obtained from grazing and browsing of natural
pasture (Table 2).
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Table 1. Estimated quantities offeed dry matter obtainable from different crop residues in
Welayita district in 1982/83 and 1983/84 production years
Crop prodi
(0
action Crop residue production
(tDM)
Conversion .
Crop 1982/83 1983/84 factor 1982/83 1983/84
Teff 10810 9 934 1.5 16215 14901
Barley 804 343 1.5 1206 515
Wheat 241 331 1.5 362 497
Maize 37 973 31122 2.0 75 946 62244
Sorghum 3 699 1628 2.5 9248 4 070
Horse bean 1025 306 1.2 1230 367
Chickpea 66 122 1.2 79 146
Haricot bean 4156 2791 1.2 4 987 3 349
Field pea 135 66 1.2 162 79
Potato 512 391 0.3 154 117
Sweet potato 8027 9366 0.3 2408 2 810
Yam 458 592 0.3 137 178
Cassava 1025 365 1.0 1025 365
Coffee 2302 1931 0.4 921 772
Lentil 17 - 1.2 20 -
Enset' na na na 65 200 22872
Banana oa na na 4880 5 272
Total 184180 118 554
' Crop production data not available. Crop residue production based on area planted (8150 and
2859 ha of enset, and 610 and 659 ha of banana, in 1982/83 and 1983/84, respectively: MOA 1984)
and crop residue yields of 8.0 t/ha per year for both crops (FAO, 1987)
Sources: Crop production data from MOA (1984). Conversion factors from FAO (1987)
Availability offeed dry matter relative to livestock population ofthe district
The livestock population of Welayita district is estimated at 468 288 tropical
livestock units (TLU) (MOA 1984; Jahnke, 1982). The availability of feed DM
was calculated to be 1.37 and 1.24 t DM/TLU per year (equivalent to 3.75 and
3.41 kg DM/TLU per day for the 1982/83 and 1983/84 production years,
respectively. The maintenance requirement is estimated at 4.6 kg DM/TLU per
day (Kearl, 1982), so the available feed supply satisfied only about 78% of the
livestock feed requirement of the area. However, the animals are reared
intensively; they are kept in the yards within the household and younger animals
or smallstock are kept inside the family's house. Hence, the animals have very
313
Table 2. Feed dry matter obtainable from different land use types in Welayita district
Land use type
Area
(ha)
DM yield
(t/ha per year)
Annual DM production
(0
Natural pasture 172602 2.0 345 204
Aftermath 53 410 0.5 26 705
Fallow land 9 261 1.8 16 670
Forest 12 771 0.7 8940
Woodland, bushland and
shrubland
65 016 1.2 78 019
Total 475 538
Source: FAO (1987)
limited exposure to inclement weather and this minimises their maintenance
requirement. The animals also have constant access to household wastes, which
gives them a decided advantage with reduced movement resulting in minimum
energy loss. This, among other factors, is reflected in near acceptable animal
performance in spite of the estimated inadequate feed supply. On the other hand,
the methods used in estimating the quantities of feeds available may not have
been accurate and therefore there is a need to re-examine them.
LIVESTOCK PRODUCTIVITY IN WELAYITASODO
The productivity of the ruminant livestock in the area is summarised in Table 3.
In general, livestock productivity is low for all classes of animals. The relatively
late age at maturity and the extended parturition intervals reflect an environment
in which animals are subjected to long periods of nutritional stress. However, the
estimated milk yield of cattle (about 500 kg/lactation, excluding milk consumed
by the calf) can be considered acceptable for unimproved local zebu cows and
this could be attributed to the practice of hand-feeding with various herbaceous
and tree plants collected from the surroundings as well as with household wastes.
Mortality rates could not be calculated from the data collected. However,
farmers reporting mortality of young animals cited drought and nutritional stress
as the main causes of death.
MAJOR CONSTRAINTS TO LIVESTOCK PRODUCTION
Shortage of grazing land and inadequate feed supply are the major problems
facing livestock producers in the area. Most of the crop residues are used as
livestock feed, but their supply is seasonal and they are used in the traditional
way, without any pretreatment and/or strategic supplementation. The cultivation
of fodder crops is limited due, among other reasons, to shortage of land. The
314
Table 3. Productivity data for ruminant livestock in Welayita Sodo, based on interview data from
102 households
Cattle Sheep Goats
Performance parameters Mean SD Mean SD Mean SD
Weaning age (months) 9.8 2.9 4.8 1.8 5.3 1.0
Age at sexual maturity (months) 52.3 10.2 11.4 4.6 11.0 6.6
Age at first parturition (months) 65.0 10.2 18.4 7.1 16.9 6.7
Parturition interval (months) 26.2 6.6 12.9 4.3 11.1 2.3
Daily milk yield (litres/head)
Maximum 2.4 0.9 - -
Minimum 1.0 0.5 - -
Mean 1.6 0.6 - -
Lactation length (months) 10.3 2.8 - -
integration of food and fodder crops in Welayita Sodo is nil to minimal due to
inadequate research data and extension services and the lack of economic
incentives to the farmers. Generally, available feed resources are not sufficient
for optimum animal production. Lack of adequate financial resources and the
absence of institutionalised credit services for investment in livestock production
are other constraints identified in the survey.
PROSPECTS FOR INTEGRATING FOOD AND FEED PRODUCTION
The traditional complementarity of food and feeds in Welayita Sodo
Acute shortage of land and inadequate feed supply constrain animal output in
Welayita Sodo but the farmers in the area are amenable to supplementary feeding
of their animals. Where cash availability limits investment in livestock
enterprises, as is the case in Welayita Sodo, the incorporation of forage legume
production with the crop subsystem may be an acceptable approach.
Leguminous forages can contribute to better utilisation of cereal crop
residues. Legumes are rich in protein and other nutrients such as minerals and
vitamins. Some forage legumes such as Desmodium intortum, Macrotyloma
axillare and Stylosanthes guianensis were shown in initial agronomic screening
trials to be suitable and productive; the trials were conducted by the International
Livestock Centre for Africa (TLCA), in collaboration with the Ministry of
Agriculture, in mid-altitude areas of Welayita Sodo and in the Rift Valley region
of Ethiopia. Some of the forage legumes were further evaluated in feeding and
digestibility trials and were found to be useful supplements to crop-residue-based
diets (Table 4).
315
Table 4. Voluntary feed intake, nitrogen retention and body weight gain of lambs fed a basal diet
ofmaize stover supplemented with different levels oflegume hays
Dry matter intake (g/kg ' per day) Nitrogen
retention
(g/day)
Supplement Liveweight gain
(g/day)g/head per day m^ stover Legume hay Total
Desmodium intortum
250 28.9a 26.8c 55.7b -0.19 7.3b
350 26.9b 35.0b 61.9a 1.51 24.9a
450 17.0c 44.7a 61.7a 1.41 30.9a
Stylosanthes guianensis
250 33.4a 26.0c 59.4b 0.82 15.0b
350 22.2b 36.6b 58.8b 1.61 13.9b
450 20.3c 44.4a 64.7a 1.37 30.3a
Within legume species, values in the same column followed by the same or no letter do not differ
significantly (P>0.05)
Leguminous fodders also make a very important contribution to the crop
subsystem. In systems with minimum fertiliser inputs legumes enhance crop
yields by reducing the rate of decline of soil fertility. Nitrogen fixed by the
legumes will be available to food or plantation crops grown by the smallholders
during concurrent and/or subsequent seasons. For example, the planting of
Desmodium intortum cv Greenleaf under coffee increased coffee berry yields by
up to 19% on peasant holdings in Welayita Sodo (Lazier, 1987). Similarly,
Haque (1990) found that intercropping maize with Macrotyloma axillare
produced significantly more total dry matter than sole maize plots, although the
intercropped plots yielded less than half as much grain as maize in pure stand.
From this finding, it was concluded that the production of large amounts of high
quality feed during the dry season by Macrotyloma axillare may be sufficient to
offset the loss in maize grain yield for farmers with mixed crop-livestock farms
and encourage them to adopt cereal-legume intercropping (Haque, 1990). But
this tentative assumption needs to be tested in the field against farmers'
responses/reactions to low grain yields vis-a-vis potential animal productivity
and marketing in Welayita Sodo. Alley cropping with leguminous multipurpose
trees such as Sesbania sesban, Leucaena leucocephala and Gliricidia spp offers
alternatives to intercropped forage legumes.
Stratification of livestock production
The adoption of forage legume technologies would also assist in stratification of
livestock production. During the dry season there is an acute shortage of feed in
the lower altitude rangelands (mainly inhabited by pastoralists), resulting in
316
substantial body weight loss and/or, during severe droughts, even death of the
animals. These losses could be partially averted by selling some meat animals
(steers and small ruminants) to highland farmers for fattening, but this exercise
would only be feasible if adequate feed can be made available in the highlands,
through improved forage production and if there are suitable marketing facilities.
In general, stratification of animal production is an advantageous strategy
for both the lowland pastoralists and the mixed crop—livestock farmers of the
highlands. Studies on animal health and on marketing are needed to assess the
sustainability of this intervention. For the pastoralists, this strategy will:
reduce feed problems for animals domiciled in the rangelands
protect the rangelands from the likely slow land degradation by adjusting
stocking rates through increased offtake
generate some cash income
And the highland mixed farmers will benefit from:
increases in income, general welfare and cash input for crop production
enhanced soil fertility in the cropping areas from animal manure and from
the forage legumes
Temporal interaction between forage supply and demand
If farmers are to adopt a sustainable integrated crop-livestock production system
there is a need to develop packages that will fit forage production and
conservation with the nutrient demand curves by the animals to exploit market
opportunities for livestock and livestock products. Researchers need to work in a
more problem-oriented and integrated approach to overcome the isolation of
disciplines like nutrition, forage agronomy and socio-economics. Research
should be extension-oriented, addressing the needs of the smallholder in
Welayita Sodo.
The four "I"s
Irrespective of the locality or the scale of operation, successful integration of
food and feed production subsystems will depend on:
institutional factors resulting from government agricultural policy
infrastructure that is conducive to agriculture production and marketing,
nationally, regionally or internationally
• inputs to the production systems—credit and financial facilities
• incentives, interrelated to agricultural policy, infrastructure and ease with
which inputs are available.
In most cases farmers' incentives to increasing agricultural productivity are
spontaneous and self-triggered. Lamentably the natural wisdom of the peasantry
in rationalising the practicabilities of these issues, as they affect their well-being,
is often assumed not to exist, underplayed or neglected by policy makers,
317
research workers and even by extension services. We might be excused,
sometimes, for assuming that, as researchers, we have better tools to evaluate
sustainability issues and other long-term interests of the farmers we are supposed
to help. That should not blind us to the fact that they, the farmers, also know
what are their priorities, in the short and medium term.
CONCLUSIONS
Our success in increasing agricultural production within the multiplicity of
existing subsystems in sub-Saharan Africa depends upon our ability to recognise
and appreciate the interrelationships of the four "I"s outlined. There is a need to
develop these infrastructures at the rural level and especially, in these days of
gender issues, to lessen the load of women in feeding their families. For Welayita
Sodo, forage production technology will be more acceptable if it fits into the
existing production system, based on the available marketing infrastructure and
financial inputs. Forages should be integrated with cropping systems rather than
displace crops. Other forages could be produced from fence lines and hedges or
in a backyard forage bank. We advocate that research should be devoted to the
temporal interaction between forage supply and nutrient demand curves as they
relate to a possible exploitation of market opportunities of animals and their
products in Welayita Sodo.
REFERENCES
FAO (Food and Agriculture Organization of the United Nations). 1987. Master land use
plan, Ethiopia range/livestock consultancy. Report prepared for the Government of
the Peoples' Democratic Republic of Ethiopia. Technical Report. AG/ETH/82/010.
FAO, Rome, Italy.
Haque 1. 1990. Effect of intercropping maize with Macrotyloma axillare on feed output
and grain yield. In: ILCA Annual Report 1989. II .CA (International Livestock Centre
for Africa), Addis Ababa, Ethiopia, pp. 86-87.
Jahnke H E. 1982. Livestockproduction systems and livestock development in tropical
Africa. Kieler Wissenshaftsverlag Vauk, Kiel, FR Germany. 253 pp.
Kearl L C. 1982. Nutrient requirements ofruminants in developing countries.
International Feedstuffs Institute, Utah Agricultural Experiment Station, Utah State
University, Logan, Utah, USA. 381 pp.
Lazier J R. 1987. The effect ofD. intortum undersown in coffee on coffee yields. FNE
Newsletter 17:16-18. FNE (Forage Network in Ethiopia). II.CA (International
Livestock Centre for Africa), Addis Ababa, Ethiopia.
MOA(Ministry of Agriculture of Ethiopia). 1984. General agricultural survey.
Preliminary Report 1983/84 (1976 Ethiopian Calendar). Vol. II. Sidamo. Planning and
Programming Department, MOA Addis Ababa, Ethiopia. 232 pp.
318
ANUTRITIONALAND ECONOMIC EVALUATION OF ANIMAL
FEED SELF-SUFFICIENCY IN CAMEROON THROUGH
INTEGRATION OF FORAGE/CROPAND LIVESTOCK
PRODUCTION
R TFomunyam andEN Tambi
Institute of Animal Research
PO Box 125, Bamenda, Cameroon
ABSTRACT
Inadequate feeding of livestock is a major problem in tropical Africa. Although
much is known about the nutritional and economic value of crop byproducts as
animal feed, little information is available on the regional distribution of these
byproducts, on their extraction rates or on levels of self-sufficiency. In
Cameroon, large quantities of cereal, tuber and root crops are produced annually
and byproducts from these crops could be used as animal feed.
This paper provides a quantitative analysis of crop byproducts available in
Cameroon. Various extraction rates are estimated and related to the numbers of
livestock and their nutritional requirements to determine the level of
self-sufficiency in crop byproducts as animal feed. Results indicate that nutrients
from crop byproducts are currently in short supply and that the byproducts are
underexploited for feeding animals. Integration of crop and animal production
would be a way of alleviating animal feed problems.
RESUME
Etude nutritionnelle et economique sur iautosuffisance en aliments du betail
au Cameroun grace a une production fourragère/vegetale et animale intégrée
Les penuries d'aliments du betail constituent un problème sérieux en Afrique
tropicale. Alors que I'on connait relativement bien la valeur nutritionnelle et
économique des sous-produits agricoles utilises dans I'alimentation des animaux
d'élevage, on nepeut en revanche en dire autant de leur répartition
geographique, des taux d'exploitation desplantes ou de la part des besoins
qu'ils permettent effectivement de couvrir. Au Cameroun, onproduit chaque
annee d'importantes quantites de cereales, de racines et de tubercules, cultures
319
dont les sous-produits pourraient entrer dans l'alimentation des animaux
d'élevage.
Cette étude présente des données chiffrées sur ces sous-produits agricoles.
Les taux d'exploitation des diverses cultures ont éte estimés puis utilisés, compte
tenu des effectifs animaux et de leurs besoins nutritionnels, pour determiner la
part des besoins en aliments du betail que ces sous-produits pourraient
permettre de couvrir. Les résultats révèlent que ces sous-produits nefournissent
pas suffisamment d'élements nutritifs aux animaux et sont en outre sous-utilisés
dans I'alimentation animale. Uneproduction végétale et animale intigrée
pourraitpermettre d'améliorer l'alimentation des animaux d'élevage au
Cameroun.
320
FEED PRODUCTION AND UTILISATION BY DUAL-PURPOSE
GOATS IN SMALLHOLDER PRODUCTION SYSTEMS OF
WESTERN KENYA
K Otieno1, JFM Onim2 andPP Semenye2
1Small Ruminant Collaborative Research Support Program (SR-CRSP)/Kenya
Agricultural Research Institute (KARI)
PO Box 252, Maseno, Kenya
^Vinrock International Institute for Agricultural Development/SR-CRSP
PO Box 252, Maseno, Kenya
ABSTRACT
The yields and quality of pastures, fodder grasses and food-crop-related sources
of feeds in western Kenya are reviewed.
Yields of up to 5.8, 40, 1 and 14.1 t DM/ha for pastures and fodder grasses
(per year) and maize thinnings and sweet potato vines (per season), respectively,
are reported. Deficiencies in phosphorus and sodium in pastures in the region are
reported. The potentials and limitations of the feed resources in the region with
respect to the feed needs of dual-purpose goats are discussed.
RESUME
Production et utilisation des aliments du bétailpar la chèvre à doubleJin en
petit élevage dans l'ouest du Kenya
La production et la qualité des herbages des parcours, des graminées
fourragères et des sous-produits des cultures vivrieres rencontrés dans I'ouest du
Kenya ont eté analysées dans cette etude.
Des rendements pouvant allerjusqu'à 5,8; 40; 1; et 14,1 t/ha ont eté
enregistrés respectivement pour les herbages des parcours et les graminées
fourragères (par an), les produits du demariage du maïs et les tiges de patate
douce (par saison). Les carences des parcours de cette région en phosphore et en
sodium ont eté decrites et les potentialités ainsi que les limites des ressources
alimentaires disponibles surplace ont eté examinées.
321
INTRODUCTION
Over the past 10 years the Small Ruminant Collaborative Research Support
Program (SR-CRSP) has been undertaking multidisciplinary farming systems
research in the intensive farming regions of western Kenya, with a view to
developing an entire production technology package for dual-purpose (meat and
milk) goats. The research has been concentrated mainly in selected sites
(clusters) within Kakamega and Siaya districts.
Kakamega district, at an altitude of 1400-1850 m, is considered to be a
zone of high agricultural potential (Pratt et al, 1966); it has high annual average
rainfall of 1200-2100 mm, distributed bimodally, and lush vegetation. According
to Jaetzold and Schmidt (1982), however, 85% of the district is covered with
infertile Acrisols except for a small fertile area of Nitosols around Kakamega
town.
Siaya district, on the other hand, is considered to be a zone of medium
agricultural potential (Pratt et al, 1966). Rainfall is bimodal but lower than in
Kakamega district and second season rains are less reliable. Annual average
rainfall is about 1140 mm, ranging from 800 mm at the shores of Lake Victoria
to 2000 mm near the border with Kakamega. The altitude ranges from 1140 to
1500 m. Soils here are generally of low fertility; they range from black cotton
soils along the lake shores to red friable loams in the north-east of the district.
According to Jaetzold and Schmidt (1982) the dominant soils in the district are
mainly soils developed on basic igneous rocks and occur on lower level uplands.
They include Luvisols, Nitosols and Ferralsols, the later being limited in fertility
and water-holding capacity.
One of the major concerns of the SR-CRSP has been to study the crop and
forage production systems currently used by smallholders in the region and to
develop and test interventions to improve feed production without adversely
affecting food-crop production. This paper highlights some of the research
findings. It also examines the practical implications of these results with respect
to the utilisation of these feeds by the dual-purpose goats being introduced in the
region by SR-CRSP.
MATERIALS AND METHODS
Study sites (clusters) were chosen in Kakamega and Siaya districts to represent
two agro-ecological zones. The sample sites used were drawn from a much
larger national sample frame which had been designed earlier by Kenya's
Central Bureau of Statistics of the then Ministry of Finance and Economic
Planning for use in the first phase of its Integrated Rural Surveys.
After the selection of the study sites and identification of households within
each site, a baseline survey was undertaken to provide information on such
aspects as household composition, land-use patterns, livestock numbers and
types and other capital resources. Monitoring surveys then followed routinely at
322
28-day intervals to assess the seasonal changes in farming activities, quantity and
quality of feeds, and condition of the animals (Sands, 1983). Samples of the
major feeds consumed by livestock were taken at intervals over a year and their
quality determined by laboratory analyses. After the surveys, several
experiments were carried out, both on-station and on-farm, to develop feed
production technologies which can be integrated into the existing cropping
systems of the region (SR-CRSP, 1981-90a, b). Technology packages
(Techpaks) have been developed and are being tested on the farms. The adoption
patterns of the individual components of the Techpaks are being monitored.
RESULTS AND DISCUSSION
The major sources of feed for livestock in the smallholder farming systems of
the two districts in western Kenya are mainly unimproved, uncultivated
communal grazing areas, roadsides, homesteads, school compounds, planted
fodder grasses and food-crop-related sources.
Natural grazing
The natural pastures in the region consist mostly of grasses of the genera
Cynodon, Hyparrhenia, Digitaria, Pennisetum, Loudetia, Sporobolus and
Cymbopogon.
There are scanty data on the potential productivity of these pastures.
Goldson (1977), however, reported a mean annual yield for 18 pastures in six
small farms in the region to be 4747 kg DM/ha. Basing their estimates on
Goldson' s results for botanical composition and annual rainfall, Sands et al
(1982), working in the same region, gave specific DM yield figures for
Kakamega and Siaya farms as 5757 and 3752 kg/ha per year, respectively. Of
these annual totals, the long rains contribute 3838 and 2502 kg/ha per season for
Kakamega and Siaya while the short rains contribute 1919 and 1250 kg/ha per
season, respectively. Table 1 shows some estimates of on-farm grazing DM
yields by farm size classes based on the seasonally available grazing areas. It can
be seen from the foregoing that the greatest problem is lack of precise
information on the productivity of the available grazing areas which still
contribute over 50% of the feed resources of livestock in the region. This
information would be useful in designing feeding programmes for the livestock
in a situation where the opportunity cost of growing feeds would be too high and
labour is constraining.
The species composition of the pastures varies with district, microclimate
and season. Table 2 gives a summary of the quality parameters for some of the
dominant species across the two districts. The crude-protein (CP) values for C.
dactylon, P. purpureum and roadside mix compare favourably with values
reported for grasses by other workers, especially for early stages of growth
323
Table 1 . Annual production offodder and digestible energy from grazing areas
Short rains (1980) Long rains (1981)
Farm size
(ha)
Dry-matter
yield (kg/farm)
Digestible-energy yield Dry-matter Digestible-energy yield
(MCal/farm)(MCal/farm) yield (kg/farm)
<05 295 761 516 1338
0.5-1.0 576 1489 716 1828
1.0-1.5 1257 3245 1202 3002
1.5-2.0 1336 3501 1786 4610
>2.0 2384 6150 1989 5043
Source: Sands et al (1982)
(French, 1943; Thairu and Tessema, 1987). The CP value for C. afronardus is,
however, more characteristic of late stage of growth or dry season. Most of the
areas in Siaya district are, unfortunately, dominated by this grass which is also
deficient in calcium, phosphorus, magnesium and zinc. It is also low in
digestibility and digestible-energy content as well as in dry-matter intake, and
these conditions persist throughout the year (Sands et al, 1982).
The macro- and microelement levels of pastures are equally important and
their importance in livestock production has been adequately documented by
Underwood (1966) for temperate regions. The mineral levels in pastures in
western Kenya have been reported by Sands et al (1982), Musalia et al (1989)
and Mbwiria et al (1984). Table 3 gives a summary of the results. It is apparent
from the data reported by Sands et al (1982) and Musalia et al (1989) that the
sampling method used has a real effect on the results obtained in mineral
analysis for samples taken from the same study area. Whereas Sands et al (1982)
collected samples of individual grass species at intervals over a year and pooled
these per species for analysis, Musalia et al (1989) collected representative
samples of forage materials consumed by goats on a monthly basis for a period
of five months covering both the wet and dry seasons. The latter workers
reported generally higher levels of minerals. For example, for the
macroelements, it is only phosphorus and potassium (in C. dactylon and C.
afronardus) levels which were higher in the data of Sands et al (1982) than in
those of Musalia et al (1989). For the microelements, it is only copper levels in
the data of Sands et al (1982) that were close to those of Musalia et al (1989), the
rest being very low. Again Musalia et al (1989) indicated higher mineral levels
for lower altitudes than for higher altitudes. Since Musalia et al (1989) were
mimicking grazing goats when taking their samples their results are probably
closer to the practical situation. This is because a grazing animal is usually able
to select a diet of higher quality than that of the average pasture.
It is, nevertheless, clear from both studies that Mg is adequate in the area
irrespective of sampling method. The same is true of Fe which is exceptionally
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Table 2. Mean quality parameters for some ofthe dominant grass species in western Kenya
C. dactylon C. afronardus
Mean SD
P. purpureum
Mean SD
Roadside mix
Quality parameters Mean SD Mean SD
Crude protein 21.25 1.00 6.56 2.17 10.06 2.96 18.73 5.52
Neutral detergent
fibre (NDF)
64.56 4.03 74.36 1.35 65.92 3.72 69.39 6.86
Acid detergent fibre
(ADF)
31.55 1.24 44.90 2.34 38.25 3.54 33.59 4.08
Hemicellulose 33.21 2.87 29.46 1.50 27.67 1.68 35.80 3.72
Cellulose 27.33 1.38 38.13 1.70 34.28 2.84 29.25 3.35
Lignin(L) 4.02 0.38 6.78 0.86 3.97 1.09 4.34 0.89
IVADF 0.13 0.01 0.15 0.01 0.10 0.02 0.13 0.02
Silica 2.32 0.56 3.31 0.45 4.40 0.61 2.67 0.52
In vitro cell -wall
digestibility
69.79 4.42 45.46 11.48 64.81 5.47 69.42 5.36
In vitro organic-
matter digestibility
79.02 2.80 55.87 9.57 72.66 4.85 76.23 5.17
Predicted cell -wall
digestibility
59.97 3.83 54.49 2.83 67.94 5.49 60.02 4.18
Predicted organic-
matter digestibility
78.69 3.00 69.26 2.61 86.05 6.30 75.89 5.88
Predicted digestible
energy 3.14 0.11 2.12 0.39 2.90 0.19 3.06 0.21
(MCalAg DM)
Predicted dry-matter
intake
(8/kgBW0-75)
61.43 5.92 43.30 3.57 59.50 5.73 52.35 11.20
Predictions based on summative equations of Goering and Van Soest (1970)
Source: Sands et al (1982)
high and Na which is low. It is apparent from this that it is difficult to rely on
experimental data for establishing mineral supplementation regimes for grazing
livestock and more so for those that browse as well.
It is known that concentrations of mineral elements in forages are generally
dependent upon the interactions of edaphic, biotic and climatic factors
(McDowell, 1976). Specific regional differences in soil characteristics such as
differences in geological formations, drainage and pH, account for most of the
naturally occurring mineral deficiencies in livestock (Hartmans, 1970; Mitchell
et al, 1957; Latteur, 1962; Pfander, 1971;). Some differences are species-specific,
some plants being able to accumulate higher levels of particular mineral
elements than others growing on the same soil (Beeson, 1961). Stage of maturity
325
Table 3. Macro- and microelement levels in pastures in western Kenya
g/kgDM mg/kg DM
Sample analysed Ca P Mg K Na Fe Zn Cu Mn
C. afronardus 1.56 2.2 0.9 16.3 0.012 75 19 2 12
P. purpureum 2.12 3.5 1.4 54.8 0.038 51 18 5 80
Roadside mix* 4.72 3.3 1.9 3.8 0.122 202 49 9 77
Tethering sites
Grass 3.60 1.6 1.8 5.1 0.20 222 28 7 118
Browse 6.30 1.3 2.1 3.4 0.19 317 33 13 111
28 genera of grasses 3.70 2.8 3.1 28.0 0.60 480 34.9 29.4 165
Expected range 0.40 0.2 0.3 - 0.01 - 1.0 1.1 9
to to to to to to to
60 7.1 10 21.2 120 100 2400
Critical level (goats) 3.60 2.7 0.9 - 0.9 15 45 7 45
* Roadside mix is mainly Digitaria scalarum and Cynodon dactylon
Data for tethering sites are means of four study sites (Maseno. Masumbi, Hamisi and Kaimosi)
Sources: Sands et al (1982); Musalia et al (1989); Kayongo-Male and Thomas (1975); Minson (1977;
of pastures also affects levels of mineral contents with elements such as P, K,
Mg, Na, CI, Cu, Co, Zn and Mo declining as the plant matures (Underwood,
1966). Pasture management and yield also affect plant mineral composition
through, for instance, grazing pressures which will determine the predominant
species of forage in an area and consequently affect mineral composition.
Mineral requirements, on the other hand, are highly dependent on the level
of productivity (ARC, 1965; NRC, 1970) and breeds (Phillips, 1956; Correa,
1957; Wiener and Field, 1969). For example, under improved management
practices where levels of milk production and growth rates are highly improved,
mineral nutrition becomes a crucial part of the management strategy. It is,
however, difficult to pinpoint specific mineral requirements since exact needs
depend on the chemical form in which the mineral is available and
interrelationships which exist between them, such as occur with Ca and P.
Although estimates of requirements are useful, they can only provide guidelines
and cannot be a replacement for the critical diagnostic test—a positive response
to correction of a suspected deficiency.
In summary, pastures in western Kenya are generally low in P and Na and
these deficiencies are more elaborate in some grass species than in others.
Phosphorus levels in Cymbopogon, for example, are inadequate to support milk
production and acceptable fertility levels. The grass species is also low in Mg,
Zn, and Na. The excessive levels of Fe can have adverse effects by increasing
326
the likelihood of Cu deficiency developing. It has been shown that a relatively
minor increase in dietary iron to almost 1 g/kg for cattle rapidly reduced liver
plasma copper to concentrations indicative of deficiency (Humphries et al, 1981).
Fodder grasses
Fodder grasses are mainly important as cut-and-carry sources of feed. The most
widely grown fodder grass in Kenya is Napier grass (Pennisetum purpureum)
and its derivatives such as bana grass (P. purpureum x P. typhoides) which is the
one mostly recommended for dairy enterprises. Productivity of bana grass varies
from one area to another and depends on whether or not fertiliser or manure is
applied. Yields of up to 10 t DM/ha after eight months of growth have been
reported (KARI, 1985). This represents on average a daily growth rate of about
180 kg/ha.
In western Kenya, Mathuva et al (1985) reported a DM yield of 3.4 t/ha for
a first cutting height of 1.3 m with a crude-protein level of 13.3% when fertiliser
(NPK 20-20-60) was applied at the rate of 100 kg N/ha. The cumulative yield
for a year (three cuts) was 40 t DM/ha.
The quality of Napier grass at utilisation stage is often high. Sidahmed et al
(1984) reported an average in vitro apparent dry-matter digestibility of 76.2% for
western Kenya. Research on the use of the Napiers in small ruminant production
systems is still scarce. However, studies by van Eys et al (1986) have shown that
goats fed only Napier grass of 6-8 weeks regrowth with a 12% CP content had
an average daily weight loss of 1 g/day compared to a weight gain of 21 g/day
for goats fed Napier supplemented with Gliricidia maculata, Leucaena
leucocephala or Sesbania grandiflora. Thus, although CP requirements of
ruminants for moderate levels of production are met at dietary DM
concentrations of 11-12% (ARC, 1980), this study showed that productivity of
goats fed Napier grass containing otherwise adequate levels of CP may still be
limited by the inefficient utilisation of nitrogen. This is again demonstrated in a
study by Yates and Panggabean (1988), in which goats were offered either a
basal diet of Napier grass ad libitum with no supplement or Napier grass
supplemented with either an energy- and protein-containing concentrate or fresh
chopped Leucaena leaves and small twigs, both supplements being offered at
levels of 25, 50 or 75% or ad libitum. The objective of this study was to look at
the effects of increasing amounts of supplements on feed intake and
performance. Those animals which were on 100% Napier grass lost weight at the
rate of 19 g/day whereas there were positive responses in liveweight change with
increased intakes of concentrates and Leucaena, with maximum liveweight gains
of 76 and 43 g/day for ad libitum concentrate and Leucaena, respectively. It was
shown that to maintain liveweights, approximately 180 and 220 g/day of
concentrate and Leucaena, respectively, were required in addition to the basal
diet. The efficiency of protein utilisation can thus be increased by
supplementation with tree legumes.
327
Food-crop-related sources
Fresh feeds
The major food crops in western Kenya include maize (Zea mays), beans
(Phaseolus vulgaris), sweet potatoes (Ipomoea batatas), sorghum (Sorghum
vulgare) and cassava (Manihot utillisima). The distribution of these crops in the
region follows the agro-ecological zones, with cassava and sorghum being
mostly predominant in the lower altitude zones of Siaya district.
The interactions between the food crops and animal production systems are
stronger in Kakamega than in Siaya district. This is so because, with a population
density estimated at over 800 persons/km , Kakamega district has very little land
left for grazing. Maize, which is the major cereal crop in the district, is also a
major source of feed for livestock. It can generate feeds through thinning and
leaf-stripping just before the crop is ready for harvesting of ears. Usually a
farmer would plant more than one seed per hill as a security against germination
losses. The extra seedlings are eventually thinned out at weeding and are a useful
source of feed, particularly for smallstock. Depending on the original plant
population, between 350 and 1000 kg DM/ha can be generated with a mean
crude-protein content and in vitro dry-matter digestibility of 21 and 59%,
respectively. Additional feed can be generated in this way just after silking stage
from those plants that will have arborted.
Leaf-stripping can begin 90 days after planting with the removal of one leaf
per plant per week, starting with the bottom leaves. Four leaves, including the
flag leaf and the leaves subtending the cobs, should be left on each plant. This
procedure can give about 800 kg DM/ha if done for up to nine weeks. Table 4
shows some estimates of quality reported for fresh and dry (hay) leaf-shippings.
It has been shown that fresh maize leaves contain sufficient protein, macro
elements and energy to support lamb gains at about 100 g/day with an intake of
770 g/day and food conversion efficiency of 8-10 (Kayongo-Male and Abate,
1982).
Sorghum can also provide thinnings and strippings, although early stripping
should be avoided as it can have a negative effect on grain yield. The advantage
with sorghum is that after harvesting the heads the crop can be ratooned and the
regrowth used as feed. However, all sorghums (grain or forage types) contain at
least trace amounts of cyanogenic glucoside. When an animal feeds on the plant
the glucoside is broken down by a glucosidase enzyme and hydrogen cyanide is
released; the enzyme is present both in the plant tissue and in the rumen liquor.
The hydrogen cyanide released is rapidly absorbed into the bloodstream where it
combines with haemoglobin to form cyanohaemoglobin which does not take up
oxygen. The poisoned animal then dies from respiratory paralysis. To reduce the
chances of poisoning, it is better to avoid grazing wilted or very young plants,
and grazing very hungry animals.
328
Content (%DM)
Fresh leaves Dry hay
128 9.5
41.8 47.5
6.5 6.3
55.7 50.5
0.60 -
0.25 _
Table 4. Quality estimates offresh and dry (hay) maize leafshippings
Quality parameters
Crude protein
Acid detergent fibre
Lignin
In vitro dry-matter digestibility
Calcium
Phosphorus
Source: Adapted from Kayongo-Male and Abate (1982)
The other major food crop in the region with potential for feed is the sweet
potato which is traditionally grown to provide tubers for human consumption.
Several cultivars occur in the region, often planted together in mixtures, and they
differ in their potential for tuber and vine production. Karachi (1982) evaluated
31 local cultivars for their tuber yields and protein contents of both tubers and
vines after nine months of growth. He observed significant differences in tuber
protein content, mean tuber numbers per square metre, mean tuber weight and
tuber yields. There were also significant differences in dry-matter content of the
vines. On the basis of these observed differences he classified the cultivars into
vine, tuber, and multipurpose types (Table 5). Similar studies have been done at
Maseno using cultivars collected within a 15 km radius around the Maseno
research station (Onim et al, 1985). Large differences in tuber and vine yields
were again observed, the best tuber-yielding cultivar giving 20.9 t/ha of fresh
tuber (equivalent to 6.81 t DM/ha) with a crude-protein content of 8% after three
months of growth. The poorest tuber yielder gave the highest vine yield of 14.1 t
DM/ha in eight months, indicating a negative relationship (r=-0.36) between
vine DM yield and tuber fresh-weight yield. The mean vine yield of 8.5 t DM/ha
in eight months is much higher than the range of 4.0-5.6 t DM/ha per harvest
reported by Ruiz et al (1980). The performance of sweet potatoes in western
Kenya is thus very good and the observed large and significant variations
(P<0.01) among the forage parameters and tuber yields indicate a potential for
improvement through selection. In terms of forage production a high vine:tuber
ratio would be the ideal choice. However, under smallholder conditions where
tubers are equally in high demand, a compromise between tuber and vine yield is
a better option and this is where the multipurpose types become most appropriate.
Nutritional studies at Maseno using crosses of Toggenburg on East African
goats have shown differences in dry-matter intakes of sweet potato vines
according to the physiological status of the animals, with the lowest intakes
being recorded in dry does (2.5-2.8% body weight) followed by kids of six
months of age (3.9-4.8% body weight) and then lactating does (6.1-6.8% body
329
Table 5. Classification ofsweet potatoes on the basis oftuber and vine yield
Tubenvine Vine:tuber Total dry-matter yield
Purpose Cultivar ratio ratio (t/ha)
Tuber Muibei 0.5 1.9 17.7
3011 0.5 2.0 17.4
3009 0.8 20 21.3
Giganda (E) 1.0 1.0 16.2
Multipurpose Nyaliech 0.3 3.5 28.6
Opiemo 0.4 2.5 29.6
Nyakonde 0.6 1.7 28.9
Mania 0.6 1.7 21.0
Vines Namunjuna 0.2 6.4 21.0
Calorine lea 0.2 4.6 21.9
Musinyamu 0.3 3.7 24.0
Toilo 0.3 3.5 20.8
Source: Karachi (1982)
weight) (Brown and Nderito, 1982). These differences would be expected,
although the high value recorded for the lactating does is more characteristic of
temperate dairy breeds. Values of up to 5-7% of body weight nave been cited as
suitable for dairy goats in a temperate environment (Mackenzie, 1967).
Devendra (1967) reported a value of 1.6% as the maintenance level for Kambing
Katjang goats (meat) in Malaysia. When the same goats were placed on three
different planes of nutrition above maintenance, the value rose to 2.2, 2.6 and
2.7% for each level, respectively.
Dry-matter intake (DMT) as a percentage of body weight thus rises from
that of meat goats through the dual-purpose types to the highest levels being
achieved in the dairy types. Indeed, for meat and fibre production, goats seldom
exceed DMI above 3% of body weight. Again, although the DMI for dairy
breeds are higher they vary depending on breed-environment interaction.
Typical values are about 3.3% for indigenous goats in the tropics, 3.6% for
exotic breeds introduced in the tropics and 5.0% for goats in temperate regions.
The relatively lower intakes for tropical dairy breeds and also for exotic breeds
imported into the topics are attributable to a combination of body size and high
ambient temperatures which tend to depress appetite.
The very high DMI values for lactating does reported under experimental
conditions in Maseno are surprising for a feed with high water content (86%)
given that a high level of water in feed has been reported to be one of the main
causes of low DMI in the region (Semenye et al, 1989). Indeed in all the intake
studies undertaken in Maseno so far the DMI for vines have been the highest
330
(Brown and Nderito, 1982; Said et al, 1985). The one advantage with the high
levels of water in vines is that a goat on the diet does not require free water
unless it is a lactating doe producing over 2.5 kg of milk per day (Brown et al,
1983). However, when offered to a lactating doe as a sole diet it can only support
suboptimal levels of production. It is more appropriate for growing goat kids that
can be weaned on it much earlier (three weeks postparturm) after achieving
almost three times their birth weight. Early weaning has the advantage of
releasing milk for the farm family.
The quality of the vines is high with a CP of over 20% and a digestibility of
about 70%, which compares well with dry-matter digestibility values reported by
other workers (Ffoulkes et al, 1978; Ruiz et al, 1980).
Crop residues
Maize stover is by far the most abundant cereal crop residue in Kenya with an
estimated annual availability of up to 5 million tonnes, accounting for over 70%
of the total annual production of the lignified arable farm byproducts (Said et al,
1982). Its use in livestock feeding is, however, mostly limited to small-scale
farms. In western Kenya, Sands et al (1982) reported that stover yields were
about 150% of the grain yield; this estimate was based on field measurements in
which grain accounted for 37-49% of maize plant DM at harvest. Table 6 shows
estimates of these yields according to farm classes. In more recent studies, Onim
et al (1986) estimated stover yields for different maize cultivars, both local and
commercial, under experimental conditions in Maseno. Under these conditions,
in which the local cultivars had been selected specifically for double cobs and all
trial plots received fertiliser, stover and grain yields were much higher than those
obtained from farmers' fields and in this case the ratio of crop residue to grain of
2:1 proposed by Owen (1976) would not be applicable (Table 7).
Table 6. Estimated stover yield in western Kenya according tofarm size classes
Maize stover yield (kg/farm)
Farm size
(M Short rains (1980) Long rains (1981)
<05 99 348
0.5-1.0 168 736
1.0-15 149 1043
1.5-2.0 273 1648
>2.0 279 1893
Siaya 162 584
Kakamega 192 1221
Source: Sands et al (1982)
331
Kaimosi Double Cobber 6 494
Hamisi Double Cobber 7 136
Nyahera Double Cobber 5 691
Masumbi Double Cobber 5 803
H614 7 395
H511 4 926
H622 5 901
Mean 5 861
Mean grain to stover ratio
Table 7. Long-rains grain and stover yields ofdifferent maize culdvarsplanted under
experimental conditions at Maseno
Grain yield Stover DM yield
Maize cultivar (kg/ha) (kg/na)
7 269
6 778
7177
5 765
10 233
6224
6 603
7150
1:1.2
The value of maize stovers as livestock feed is, as with other crop residues,
limited by their low digestibilities and crude-protein and mineral contents. Their
nutritive value can be improved either by treatment methods that increase the
availability of nutrients by breaking down the lignocellulose constituents, or
through supplementation methods that add deficient nutrients or correct nutrient
imbalances. It has been shown that treatment of roughages with anhydrous or
aqueous ammonia or with urea can increase digestibility, intake and liveweight
gain in ruminants (Jackson, 1978; Sundstol et al, 1978).
However, the effect of ammoniation is influenced to a certain extent by type
of roughage and quality before treatment (Sundstol et al, 1978). Generally,
materials of lower digestibili ty respond better to treatment than those of higher
initial value. In some cases ammoniation has been reported to decrease N
digestibility of roughages (for example, Oji et al, 1977). Recent work in Kenya,
Tanzania and Bangladesh has shown that Magadi soda (a natural alkali salt
deposit) is effective in improving digestibility and intake of straws (Musimba,
1980; Kategile et al, 1981; Saadullah et al, 1981).
In studies with male castrated sheep, Butterworth and Mosi (1986) reported
that estimated intakes of metabolisable energy (ME) for crop residues fed alone
were not sufficient for maintenance of a 20 kg male castrated sheep. However,
when levels of Trifolium tembense hay supplement were increased successively,
there was an increase in average ME intake sufficient to support modest levels of
production. There were also significant increases in nitrogen retention,
particularly for maize stover, oat straw and wheat straw diets.
Thus legumes appear to be a viable option and one that would be more cost
effective under smallholder conditions. Moreover, the conventional energy and
protein feeds such as grains and oilseed cakes are neither readily available nor
affordable to the small-scale farmer.
332
Multipurpose tree legumes
Tree legumes are currently gaining prominence in sub-Saharan Africa due to
their many uses and the fact that they can easily be integrated into existing
cropping systems. With the increasing demand for agricultural land in western
Kenya, many of the indigenous tree legumes are being phased out as more land
is cleared for cropping. Some of the introduced legume species such as Leucaena
are slow to establish and vulnerable to wild ruminant browsers at the seedling
stage. There are therefore just a few trees scattered within the homesteads and
these play a negligible role as sources of feed. One of the indigenous species
which grows readily in the area is Sesbania sesban. It is seen in many farms left
standing between crops; farmers believe, and rightly so, that it improves the
yield of the companion crops. This is understandable taking into consideration
the fact that it is a profusely nodulating legume. However, little information is
currently available on the response of Sesbania to cutting management for forage
generation and work is currently being undertaken in SR-CRSP to establish this.
Major limitations to the utilisation of available feeds by dual-purpose goats
The areas available for natural grazing are rapidly diminishing due to the
increasing human population and the attendant increase in demand for cropping
land. Even in Siaya district, where communal grazing areas have been relatively
abundant, the effect of population increase is beginning to show. Moreover, the
land demarcation policy has meant that those areas that were initially used
communally are now under strict individual ownership. The few areas that are
still left available are dominated by poor grasses of the genus Cymbopogon.
These grasses cannot maintain adequate levels of fertility and productivity. The
levels of dry-matter intake recorded in the district with grazing goats is very low
(1.6% of body weight) with consequent deficits in energy intakes and thus poor
growth (Karimi et al, 1985). In Kakamega district the available grazing areas are
seriously overgrazed with the consequence that the actual amount of herbage on
offer at any particular time is lower than the estimated potential productivity.
This has a severe effect on dry-matter intake.
The Napier grasses, particularly bana grass, form an important source of
cut-and-carry forage in the region. However, the plots under these are often very
small and most of them are on embankments of erosion-control cut-off drains
and terraces. Moreover, they are rarely given manure or fertiliser and being very
demanding crops they cannot do well under poor soil conditions. The small plots
are often over-harvested and in many cases they are established under eucalyptus
trees where the shade affects productivity. It is difficult to convince farmers to
clear the trees since these are important sources of income. Introduction of
shade-tolerant grasses may be a solution. There is also an inefficient utilisation
of the Napier grass due to wastage at feeding time. Many farmers simply throw
the harvested grass on the ground and goats, being fastidious feeders, will not eat
333
any contaminated forage. SR-CRSP scientists are making a concerted effort to
encourage farmers to hang the feeds, and this is currently picking up well.
Food crops still remain a very important source of feeds in mixed farming
systems in the region. However, these can only provide maintenance diets in the
form of leaf strippings, thinnings, stovers and sweet potato vines. It is therefore
necessary to integrate tree legumes into the cropping systems to provide a source
of supplement to the crop-related feeds. There is an urgent need to develop
cropping systems that would incorporate both food crops and tree legumes in a
self-sustaining manner and with optimal productivity under smallholder
conditions. The SR-CRSP is already experimenting with a model of such a farm.
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338
ECONOMIC IMPLICATIONS OF FORAGE INNOVATIONS ON
SMALLHOLDER FARMS IN WESTERN KENYA
FB Nyaribo1, JFMOnim1 andD L Young1
1 Winrock International Institute for Agricultural Development
Small Ruminant Collaborative Research Support Program (SR-CRSP)
PO Box 252, Maseno, Kenya
Department of Agricultural Economics
Washington State University
Pullman, WA 99164, USA
ABSTRACT
In response to a declining forage base, the Small Ruminant Collaborative
Research Support Program (SR-CRSP) has developed a number of low cost
forages and forage preservation techniques for the dual-purpose goat technology
currently on trial on smallholder farms in western Kenya. Representative whole
farm linear programming models incorporating a number of the new forages
were constructed for three farm sizes in Hamisi Division. Food and cash crops,
existing forages and zebu cattle were also included in the models. Results
showed a high degree of complementarity between crop and liverstock
production. Livestock stocking rates increased considerably with the smallest
farm realising the largest net income gains from the new technologies.
RESUME
Incidences economiques des innovations en matiere de technologies
fourragires introduites dans lespetites exploitations de I'ouest du Kenya
Face à la degradation de la base de ressources fourragères, le Programme
d'appui a la recherche concertée sur lespetits ruminants (SR-CRSP) a mis au
point un certain nombre d'espèces fourragères et de techniques de conservation
des fourrages bon marche destinées a I'élevage des caprins a double fin.
Celles-ci sont actuellement évaluees dans depetites exploitations de la région
d'Hamisi dans I'ouest du Kenya. A cet effet, des modèles de programmation
liniaire tenant compte de toutes les activites agricoles, des caractéristiques de
certaines nouvelles varietés fourragères et de la taille des exploitations ont ete
339
élabores. Les autres parametres pris en compte dans ces modeles sont les
caractéristiques des cultures vivrieres et des cultures marchandes ainsi que
celles des espècesfourragères traditionnelles et de I'élevage bovin. Les analyses
effectuées font ressortir une forte complementarité entre la production veg&ale
et I'élevage. Ces innovations technologiques permettaient d'augmenter
considirablement les taux de charge despetites exploitations etpartant, de
maximiser les benéfices nets des petits exploitants.
INTRODUCTION
Much of African development research has focused on crop farming to the
neglect of the livestock sector (Senga, 1976). However, small ruminants (sheep
and goats) play a significant support role in small farming systems of the world
(Winrock International, 1983). In Kenya, for example, about 43% (6.5 million)
of the country's small ruminants are reared on small farms. Between 1969 and
1978, the goat population increased by 4.8% annually, and the offtake rate rose
from 17 to 31% (Schulter, 1984). With increasing prices of other meat sources,
such as beef, sheep and poultry, demand for goats will probably continue to rise.
The agricultural sector is expected to continue to play a key role in the
Kenyan economy, especially in employment creation. According to World Bank
(1989) statistics the growth rate of the agricultural sector has steadily declined
from 4.9% in 1965-80 to 2.8% in 1980-86. Several solutions are being explored
to revitalise Kenya's agricultural development and growth. Currently research
resources are being channelled to the lower strata of livestock farmers who in
many cases still employ traditional production practices.
For the past 10 years the Kenya Small Ruminant Collaborative Research
Support Program (SR-CRSP) has been working on development of the
dual-purpose (milk and meat) goat and supporting technologies in smallholder
farms of western Kenya, using a farming systems research approach. With
increasing populations and the resultant pressure on land, the dual-purpose goat
is an appropriate livestock technology alternative to the zebu cattle which are
usually reared on these farms. The dual-purpose goat is low risk and requires
fewer capital inputs and smaller land area per unit, and yet under good
management conditions produces higher milk yields per unit of required inputs.
The overall objective of this study is to assess the economic impact of the
dual-purpose goat and new forage technologies as a means of improving
smallholder family incomes, and human nutrition, in Hamisi Division of western
Kenya. The specific objectives are to:
• determine the magnitude of economic returns from the dual-purpose goat
and forage technologies developed by the SR-CRSP in western Kenya
• determine the level of integration of the new forage technologies in these
smallholdings
• determine economic and nutrition constraints to adoption of the
dual-purpose goat.
340
MATERIALS AND METHODS
Study area
The study is being carried out in Hamisi Division, in the western highlands of
Kenya in Kakamega District. The area is classified as a high potential
agricultural zone. Annual rainfall is 1200-2100 mm, with a bimodal
distribution—the long rains season runs from March to June, and the short rains
fall between September and November. The soils are humic nitrosols with
moderate to high fertility (Hart et al, 1984). Hamisi Division is one of the most
densely populated regions of Kenya with about 615 persons/km .
The farming system in Hamisi is a sedentary mixed crop-livestock system,
with two cropping seasons. The primary food crops are maize intercropped with
beans. Secondary food crops include sweet potato, cassava, banana and a variety
of green vegetables. Tea and coffee are the major cash crops. All household keep
some livestock. SR-CRSP (1986-87) surveys indicate mean livestock numbers
per farm of 2.10, 0.20 and 0.20 Tropical Livestock Units (TLU: 1 TLU = 250 kg
liveweight) for zebu cattle, sheep and indigenous goats. But because more than
40% of participant farmers own 1 ha of land or less, these stocking rates are
considered high (Semenye, 1990; Jaetzold and Schmidt, 1982); given existing
natural unimproved grazing pastures, Jaetzold and Schmidt (1982) recommend a
stocking rate of 0.6 ha/TLU. It is clear that available land is being overgrazed.
Sources of livestock feed
Livestock feeds are derived from off-farm grazing and crop residues such as
maize stover, maize thinnings, banana peelings and sweet potato vines. The
importance and availability of any specific feed varies by season and off-farm
grazing is perhaps the most important source, followed by crop residues. Heavy
reliance on off-farm grazing is supported by the long grazing hours reported by
Conelly et al (1987).
Table 1 shows the mean cultivable and grazing land, labour and capital
endowments for small, medium and large farms in the study area. Project data
indicate no significant difference in labour availability per household so the
same figure was used for all farms. There is a negligible variability in mean own
capital per household. The small area of on-farm fallow land available for
grazing on the small and medium farms is the land around the homestead which
is not in direct competition with food crop production. On large farms a greater
area can be left fallow for grazing. Livestock nutrition budgets constructed by
Hart et al (1984) estimate an average of 0.40 ha of off-farm grazing per
household for the sample of farmers in Hamisi. Detailed descriptions of the
farming system and resource endowments for the study area have been reported
elsewhere (Sands, 1983; Nyaribo, 1989; Nyaribo and Young, 1991).
341
Table 1. Resource constraints by farm size, Hamisi Division, western Kenya
Land (ha) Labour adult
equivalent Own capital
Farm size Cultivable Grazing* (days) (KSh)
Small 0.59
1.19
201
0.50
0.60
1.39
1461
1461
1461
3051
3151
3737
Medium
Large
* Refers to the sum of on- and off-farm grazing land available. On-farm fallow grazing land is 0.10 ha
for the small and medium farms and 0.89 ha for the large farm
KSh 23 = $US 1.00 in 1990
Baseline surveys in the early phase of the SR-CRSP project identified lack
of adequate quality feeds as one of the constraints to dual-purpose goat
production (Sands, 1983). Seasonal fluctuations in the forage supply are such
that in certain months there is excess feed which is wasted if it is not stored. In
response to the shortage of livestock feed, SR-CRSP has introduced several
forage interventions and forage storage technologies (Hart et al, 1984; Onim et
al, 1985).
Study methodology
Linear programming was used to test the economic feasibility of dual-purpose
goat and forage production and storage technologies. Representative farm linear
programming models were constructed for three farm sizes for the Hamisi study
site. The linear programming model maximises gross margin, net of human
consumption, from the farm's production activities subject to fixed resource
constraints. Gross margin is defined as total revenue minus total variable costs.
The model solves for the following decision variables:
1. How many hectares to plant to food, cash and forage crops
2. The desired inventory of cattle and dual-purpose goats
3. How many animals to sell during the year
4. How much food to produce, how much to sell and how much to keep for
home consumption
5. How much cash to borrow to augment cash balances.
The main constraints are:
1. Maximum cultivable and grazing land available
2. Maximum family labour available
3. Maximum hired labour available
4. Minimum family subsistence requirements
5. Minimum livestock nutrient requirements
6. Maximum available working capital for input and food purchases.
342
The time unit is one calendar year. The year is divided into four time
periods to allow for the transfer of products and resources. The seasonal
disaggregation of the livestock component is crucial because of the seasonal
changes in the quality and quantity of forages. Also, most farming activities are
performed at specific times during the year which leads to distinct seasonal
patterns in resource use and supply (Hazel and Norton, 1986).
The livestock component generates demand for feed on a quarterly basis
which in turn determines the optimal stocking rate. This permits isolating
livestock nutrient needs that may be at risk in certain periods of the year. Dry
matter and crude protein supplied by the different sources are balanced with the
demands for livestock feeding. The requirements are specified by livestock
category and by period.
Livestock production activities
There are two dual-purpose goat breeding activities. The unit of measure is a
doe-kid unit. Nutrient requirements for the doe-kid units are the sum of those
for the lactating doe, the kid and a yearling replacement doe. The first doe kids in
April and the second in November. Weaner kids from the dual-purpose goat
production activities are available at five months of age. Nutritional
requirements are withdrawn each period the animal remains on the farm. Kid
rearing activities produce animals which are transferred to kid sale activities.
Weaner kid nutrient requirements are drawn only up to 14 months. To allow for
flexibility in sale of kids within the year, sale dates are not predetermined.
Accordingly four kid sale activities, one corresponding to each quarter, are
specified in the model. The breeding stock replacement activity allows for
yearling females to be kept for breeding stock replacement. The labour and
nutrient requirements are included in the doe breeding activity.
One cattle production activity is specified. Zebu cattle produce milk for
home consumption as well as for sale. They also produce calves and culls for
sale. The milk sale activities allow for sales of milk from both dual-purpose
goats and cows in all periods.
The model includes three livestock feeding categories; April kidding
dual-purpose goat feeding, November kidding dual-purpose goat feeding, and
cattie feeding. Livestock derive their feed from eight sources: maize stover, fresh
pigeon peas, Sudan grass, off-farm and on-farm fallow grazing, fence row
forage, pigeon pea hay, Sudan grass hay and mixed grass hay. In the model this
results in 78 seasonal feeding activities. The model determines the optimal mix
of feed consumed subject to dry-matter and crude-protein requirements. It also
determines quantities of feed to be transferred to feed-deficit months.
Other production activities of the model include intercropped maize and
beans, sorghum, vegetables and bananas. Along with maize stover, grass hay and
on- and off-farm grazing, the new forages intercropped with food crops are
Sudan grass and pigeon peas. Cash crops considered are tea and coffee.
343
Data sources
The data used in this study came from surveys conducted by SR-CRSP scientists
(SR-CRSP, 1986-87, 1987; Hart et al, 1984). SR-CRSP work covers
smallholder farmers in two agro-ecological zones and conducts on-farm trials in
six villages with a total of 150 participating farmers. In this study modelling
results from the Hamisi village with 23 farmers are reported.
MODELLING RESULTS
The different model runs are classified by type of technology and farm size. The
technologies were introduced sequentially to the traditional (base) farm. Thus:
• TI denotes traditional technology, referred to as the base model
• TH denotes the base model with the dual-purpose goat and no new forages
• Till denotes the addition to Til of new forages without forage storage
technology
• TTV denotes the full technology package which includes forage storage.
Up to 42% of the SR-CRSP participant farmers own 1 ha of land or less. It
was thus important to evaluate the impact of these technologies on various farm
sizes. Accordingly the sample was stratified into three farm sizes and the means
of the land, labour, and capital endowments for each farm size category (see
Table 1) were used in the linear programming models.
Table 2 summarises the impact of the new technologies on stocking rates
and on farm income by farm size. As anticipated, the new technologies have had
the greatest impact on the smallest farms, where the full technology package
(TTV) increased stocking rates by 767% and farm income by 497%, compared
with the base model. Results for the medium and large farms showed similar
trends, but at much lower levels; for example, farm income increased by only
22% on medium farms, and by a mere 8% on large farms, with the full package.
Small farm
(0.69 ha)
Medium- size farm
(139 ha)
Large farm
(3 ha)
Stocking
rate(TLU)*
Income
(KSh)
Stocking
rate (TLU)*
Income
(KSh)
Stocking Income
rate (TLU)* (KSh)Technology
TI 0.49 1509 0.49 9738 1.22 13792
Tn 0.73 1600 0.70 9813 1.22 13792
Tin 3.87 6946 2.73 11554 2.41 14773
TTV 4.25 9003 3.35 11906 2.95 14949
Table 2. Impact ofdual-purpose goats and newforages on stocking rates andfarm income by
farm size
* TLU = Tropical Livestock Unit (1 TLU = 250 kg)
KSh 23 = $US 1.00 in 1990
344
Figure 1 shows the shares of sales from livestock products (milk and meat)
and crop sales on small and size farms. (Relative magnitudes for the large farm
follow the trend of the medium farm. Thus conclusions regarding the medium
farm are also relevant to the large farm.) As each element of the dual-purpose
goat and forage technology package was added to the base model the share of
crop sales declined while that of livestock product sales increased. This reversal
of the contribution of livestock and crop sales to total farm sales can be
explained by the fact that farm-gate prices for meat and milk are higher than that
for maize grain, the major competing commodity. The results indicate that while
crop-livestock associations are biologically complementary, economically they
can be competitive because of the relative crop/livestock output price ratios.
Complementarity of crop-livestock production
The complementarity of crop-livestock production systems on smallholder farms
is determined by the degree of dependence of each enterprise on the other. In
western Kenya crop residues play an important role in providing forages for
livestock on the farms. This is clearly illustrated in Figure 2, which shows the
share of each forage type in total feed consumed on the small and medium farms
under the full technology package (TIV). On the large farm the new forage and
hay storage technologies contributed 37 and 15%, respectively, or 52% of the
total feed consumed, while maize stover and grazing each contributed 24% of
total. These results demonstrate that maize, which is the most important food
crop, is highly complementary with production of dual-purpose goats.
Constraints to livestock production
Four major constraints to livestock production were identified (Table 3).
Digestible energy was constraining for all farm sizes under all technology
alternatives. This finding is consistent with the study by Blackburn et al (1986)
in the same area. Grazing land and cultivable land were also constraining for all
farm sizes with the small farm realising the largest shadow price on cultivable
land. Capital was constraining for the medium and large farms. This points to the
need for credit support for smallholder farms.
CONCLUSIONS
Adoption of the new forage and forage storage technologies significantly
increased stocking rates and farm incomes on smallholder farms in western
Kenya. While all farm sizes benefited from the new technologies the smallest
farm size realised the largest net income benefits from adoption of the new
technologies. For all farm sizes maximum benefits were realised by adopting the
new forages plus the forage storage technology, that is, the full technology
345
Figure 1. Shares oflivestockproducts and crops inform sales
% share
10(h
80
60
40
20
0.69-ha farm
Livestock products
 
100
80
60 \
40
20 -I
1 .39-ha farm
 
Tl Til Till
Technology combination
TIV
package specified as TIV. Due to limited land endowment for the smallest farm,
economic competitiveness between livestock and crop production occurred at
lower farm incomes, and lower technology levels (between Til and Till) than it
did on the medium and large farms. Digestible energy, cultivable land and
grazing land were identified as constraining resources for all farm sizes. Capital,
on the other hand, was constraining for the medium and large farms. For the
346
Figure 2. Share ofvarious forages in total forage consumption
Maize stover
34%
Maize stover
32%
0.69-ha farm
 
Pigeon peas and
SEbv Sudan grass 34%
Hay 16%
Grazing 16%
1 .39-ha farm
 
Pigeon peas and
Sudan grass 33%
HfcS? Hay11%
Grazing 24%
347
Table 3. Economic results ofselected variables by technology combination andfarm size,
Hamisi Division, western Kenya
Total live Quantity DM
(kg)
Dual values
stock Farm Grazing Cultivated Operating
Farm units income Nutrientb land land capital
size (TLU)* Fresh Stored (KSh) (KSh/kg) (KSh/ha) (KSh/ha) (KSh/KSh)
I
Small 0.49 1690 na 1509 0.77 1358 7 475 0.00
Medium 0.49 1705 na 9 738 0.77 1358 7 519 0.00
Large 1.22 4220 na 13 792 0.30 294 2 045 3.90
II
Small 0.73 2049 na 1600 0.85 1509 7 475 0.00
Medium 0.70 1660 na 9 813 0.65 1153 6 169 0.96
Large 1.22 4220 na 13 792 0.30 294 2 045 3.90
III
Small 3.87 9952 na 6946 0.85 6349 11946 0.00
Medium 2.73 8367 na 11554 0.16 877 857 4.75
Large 2.41 7111 na 14 773 0.09 183 117 5.28
IV
Small 4.25 6161 1918 9 003 0.32 2346 14 816 0.00
Medium 3.35 9051 1164 11906 0.07/0.67 217 469 5.11
Large 2.95 7730 1391 14 949 0.08 161 3 5.36
' TLU = Tropical Livestock Unit (1 TLU = 250 kg)
Digestible energy was the constraining nutrient for all farm sizes under all technology alternatives.
Crude protein was also constraining for the medium farm under TIV
KSh 23 = $US 1.00 in 1990
smallest farms, land constraints imply the need for further research in output-
increasing technologies per unit of land. This will require the use of improved
management and husbandry practices and the use of high yielding maize
varieties as well as high milk and meat yielding dual-purpose-goat genotypes.
Considering the significant share of maize stover and grazing in total feed
consumption, these traditional sources of feed will continue to play a key role in
the diets of dual-purpose goats and other livestock. Livestock and crop
production were shown to be highly integrated and technically complementary.
This no doubt contributes to the sustainability of smallholder farms. However,
complementarity of livestock-crop production is tempered by economic
competitiveness due to farm-gate livestock/crop price ratios. Given the price
responsiveness of farmers the balance of farm activities will continue to shift to
livestock production the higher the output price ratios.
348
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Schulter M. 1984. Constraints on Kenya's food and beverage exports. EFPRI Research
Report 44. IFPRI (International Food Policy Research Institute), Washington, DC,
USA. 56 pp.
Semenye P P. 1990. Nutrition and managementfor dual-purpose goats: Research
highlights. Winrock International Institute for Agricultural Development, Morrilton,
Arkansas, USA; Kisumu. Lake Printers Ltd, Kisumu, Kenya. 53 pp.
349
Senga W M. 1976. Kenya's agricultural sector. In: Meyer J, Maitha J K and Senga W M
(eds), Agricultural development in Kenya. Oxford University Press, Nairobi, Kenya.
SR-CRSP (Small Ruminant Collaborative Research Support Program). 1986-87. Rapid
rural appraisal survey. Maseno Research Station, Maseno, Kenya. SR-CRSP, Nairobi
and Maseno, Kenya.
SR-CRSP (Small Ruminant Collaborative Research Support Program). 1987. Economics
project survey. Maseno Research Station, Maseno, Kenya. SR-CRSP, Nairobi and
Maseno, Kenya.
Winrock International Institute for Agricultural Development. 1983. Sheep and goats in
developing countries: Theirpresent andpotential role. World Bank Technical Paper.
Washington DC, USA. 116 pp.
World Bank. 1989. Development Report. World Bank, Washington DC, USA. 305 pp.
350
EFFET DE LA COMPLEMENTATION ALIMENTAIRE SUR LA
PRODUCTION LAITIERE ET LA CROISSANCE DES BOVINS A
MADAGASCAR
J.H. Rasambainarivo
Département de recherches zootechniques et vétérinaires (DRZV)
B.P. 4, Antananarivo 101 (Madagascar)
RESUME
Après avoir passé en revue les ressources alimentaires disponibles pour l' élevage
à Madagascar, cette étude présente quatre expériences menées pour évaluer
Y effet de diverses complémentations sur la production laitière et la croissance de
diverses races de bovins.
Dans la première expérience, des vaches laitières issues de croisements race
Frisonne x Zébu, réparties en lots et élevées sur pâturage artificiel de saison
sèche de Stylosanthes guianensis, ont bénéficié de trois niveaux différents d' une
complémentation de concentrés. Il ressort des résultats enregistrés que celle-ci
n' avait aucun effet significatif sur la production laitière.
Dans la deuxième expérience, des vaches métisses race Frisonne x Zébu
élevées sur pâturage naturel de saison sèche recevaient une complémentation de
tourteau de coton et de paille traitée ou non avec de l' urée. La paille traitée à
l' urée entraînait une augmentation significative de la production laitière et un
gain moyen quotidien pouvant aller jusqu'à 119 g. Quant à la paille brute, elle
entraînait des pertes de poids pouvant aller jusqu' à 286 g/j.
Dans la troisième expérience, des génisses croisées Renitelo x Zébu ont été
élevées pendant 42 jours sur pâturage de saison sèche, avec une
complémentation de divers niveaux de feuilles de Leucaena leucocephala et de
paille de riz traitée ou non. Le gain de poids des animaux soumis à la ration
complémentée était significativement supérieur à celui des témoins. Le niveau de
complémentation et la nature de la paille n' avaient pas d' effet significatif sur le
gain moyen de poids.
Dans la quatrième expérience, des zébus adultes ont été élevés sur pâturage
naturel de saison sèche avec ou sans une complémentation de graines de coton. Il
ressort des résultats enregistrés que les gains de poids augmentaient linéairement
en fonction de la quantité de graines de coton consommée. Les animaux élevés
uniquement sur pâturage naturel perdaient du poids.
351
ABSTRACT
Effect offeed supplementation on cattle milk production and growth in
Madagascar
After an overview offeed resources available for livestock production in
Madagascar, this study reports on four trials carried out to assess the effect of
various supplements on milkproduction and growth in various cattle breeds.
In the first trial, Friesian x zebu dairy cows divided into groups and kept on
sown dry-season Stylosanthes guianensis pasture were fed three levels ofa
concentrate supplement. Supplementation had no significant effect on milk
production.
In the second trial, Friesian x zebu cows kept on a natural dry-season
pasture were fed a concentrate ofcottonseed cake and straw with or without
urea enrichment. The enriched straw significantly increased milkproduction and
resulted in an average weight gain ofup to 119 g/day. Straw alone resulted in
weight losses ofup to 286 g/day.
In the third experiment, Renitelo x zebu heifers were kept for 42 days on a
dry-season pasture with a supplement of various levels o/Leucaena leucocephala
leaves and rice straw with or without urea treatment. Supplemented animals
gained significantly more weight than unsupplemented ones. Supplementation
level and type ofstraw had no significant effect on average weight gain.
In thefourth trial, adult zebu cattle were kept on a natural dry-season
pasture with or without a cottonseed cake supplement. There was a linear
increase in weight gains as cottonseed cake consumption increased.
Unsupplemented animals lost weight.
352
IMPROVING MILK PRODUCTION IN SMALL-SCALE DAIRY
FARMS IN BOTSWANA: INCORPORATING LEGUME FODDER
IN THE FARMING SYSTEMS
WSBoitumelo and WMahabile
Department of Agricultural Research
Private Bag 0033, Gaborone, Botswana
ABSTRACT
A research project was established to investigate the problems of milk
production by small-scale cattle owners in Botswana. The major constraint
identified was lack of adequate feed (quantity and quality), particularly during
the dry season. The research emphasis was therefore to integrate fodder crops
such as lablab (Lablab purpureus) into the farming systems and establish a
practical feeding programme based on planted fodders and harvested crop
byproducts. Participating farmers planted 1 ha with lablab, with or without single
superphosphate fertiliser. On-station trials were established to study the effects of
fertiliser application, the optimal stage of harvest and appropriate methods for
harvesting, drying and storage.
Feeding packages developed by the project were tested on-farm. A
comparative feeding trial was conducted involving Simmental-Tswana
crossbreds and Tswana milking cows fed sorghum stover supplemented with
different levels of lablab and sorghum bran as protein supplements.
During the four years of the trial (1985-1989), average lablab dry-matter
yields from farmers' fields were 1.14, 0.70, 2.82 and 0.87 t/ha. Fertiliser
application did not affect (P>0.05) lablab yields on either farmers' or research
plots, and there were no differences (P>0.05) in yields between farmers' fields
and the research plots. Lablab contained more crude protein than sorghum stover
(16.4 vs 6.4%). The lactation yield of the crossbred cows was more than twice
that of Tswana cows (3.8 vs 1.5 kg/day).
Although the major traditional crops in the project area are sorghum and
millet intercropped with cowpea and watermelon, the project has succeeded in
convincing farmers to allocate one 1 ha of land for lablab production and fodder
production has become a component of the cropping system.
353
RESUME
Amélioration de la production despetites exploitations laitieres au Botswana:
introduction des légumineusesfourragères dans les systèmes agraires
Unprojet de recherche a éte lancé pour étudier les problèmes rencontrés dans le
domaine de la production laitiere par les petits éleveurs de bovins au Botswana.
D'après les résultats de ces travaux, les pénuries et la qualite médiocre des
aliments, notamment au cours de la saison seche, constituent certains des
obstacles lesplus sérieux au developpement de la petite exploitation laitiere
dans le pays. Fort de ces conclusions, il a éte decidé de mettre l'accent sur des
travaux destinés, non seulement à intigrer des plantes fourrageres comme la
luzerne (Lablab purpureusj dans les systèmes agraires en place mais également
à élaborer un système adapte d'alimentation basé sur la culture de plantes
fourrageres et les sous-produits agricoles. Les paysans participant à ces travaux
ont semé 1 hade luzerne avec ou sans application de superphosphate simple.
Des essais en station ont en outre éte conduits en vue d'étudier l'effet de
I'engrais et de determiner le stade optimal de récolte ainsi que les meilleures
méthodes de coupe, de séchage et de conservation.
Des paquets alimentaires élaborés dans le cadre de ce projet ont éte
expérimentis en milieu réel. Un essai d'alimentation comparatifa éte réalisé sur
des vaches métisses Simmentalx Tswana et des Tswana, avec une ration
composée de paille de sorgho complementee avec différents niveaux de luzerne
et de son de sorgho comme sources de complements proteiques.
Pour les quatre ans qu'a duré cette étude (1985-1989), la production
moyenne de matiere seche de la luzerne au niveau des paysans s'établissait à
1,14; 0, 70; 2,82; et 0,87 t/ha. L'application d'engrais n'avait aucun effet
(P>0,05) sur la production de la luzerne, ni au niveau des paysans ou du projet
ni entre les parcelles des paysans et celles au projet. La teneur de la luzerne en
proteines brutes (16,4%) était supérieure à celle de la paille de sorgho (6,4%).
Enfin, les vaches métisses produisaientplus de deuxfois plus de lait (3,8 kg/j)
que les Tswana (1,5 kg/j).
Bien que les principales cultures traditionnelles de la zone d'étude soient le
sorgho et le mil, entre lesquelles étaient généralement intercales le niébe et la
pastèque, le projet a réussi à convaincre les paysans de réserver 1 hade terre à
la culture de luzerne, faisant desormais de la production fourragere une
composante àpart entiere au système agraire.
INTRODUCTION
Increasing milk production by peri-urban small-scale farmers in Botswana has
been the major objective of the Ministry of Agriculture during the current
six-year National Development Plan (1985-91). The Animal Production
Research Unit (APRU), Department of Agricultural Research, established a
354
project to investigate the problems of milk production by small-scale cattle
owners. This project is jointly funded by the Government of Botswana and the
International Development Research Centre (DDRC), Canada.
The major constraint identified was lack of adequate feed (quantity and
quality) to sustain milk production, particularly during the dry season. Large
quantities of crop residues are produced and can be harvested for dry-season
feeding of lactating and in-calf cows (Mosienyane, 1983; Mosimanyana and
Kiflewahid, 1987). However, crop residues are of low quality and cannot satisfy
the nutritional requirements of these cows. Therefore, the research emphasis has
been to incorporate fodder crops into the farming system and establish a practical
feeding programme based on planted fodder and crop residues.
Agronomic trials to examine various varieties of fodder legumes and
pasture grasses were conducted at a number of locations between 1977 and 1980
(APRU, 1980). The results indicated that from among several annual legumes
screened for drought resistance, ease of management, grazing potential and
dry-matter yield, lablab (Lablab purpureas) was the most productive and the
most easily established in the communal areas of Botswana (APRU, 1979). It has
soil requirements similar to those of cowpea, and better disease and insect
resistance, and can be grazed, ensiled or conserved as hay (Humphreys, 1978). In
addition to these qualities and its high nutrient content, it is useful in terms of
improving soil fertility in crop rotation in small-scale farm conditions (APRU,
1979).
The specific of objectives of the work described here were to determine:
• productivity and nutritive value of lablab
optimal methods for conservation
• the potential for including a fodder legume such as lablab into the
small-scale mixed farming systems.
MATERIALS AND METHODS
Fodder legume production and conservation
Beginning in 1985, the project introduced lablab to the participating farmers.
Each farmer was given 20 kg of lablab seed and 100 kg of single superphosphate
fertiliser (10.5% P) to plant 1 ha of land; the fertiliser was applied to half of each
hectare. Three 1-ha plots were also planted at Sebele Agricultural Research
Station. Superphosphate was applied at the rate of 0, 100 or 250 kg/ha on each
plot. An additional 27 ha of land were planted to study the optimal stage of
harvest and appropriate methods for harvesting, drying and storage, and for
on-station feeding trials
Lablab yield was measured using 2-m radius circular subplots from three
random locations in each of the farmers' plots and the research plots. After
measuring yield, the plants were harvested, sun-dried and stored for dry-season
355
feeding. After harvest the total quantities of lablab, crop stovers and post-harvest
residues stored by each farmer were estimated.
Feeding trial
A dry-season on-farm feeding trial was carried out to determine the voluntary
feed intake and performance of Simmental-Tswana crossbred and Tswana
lactating cows fed sorghum stover supplemented with various levels of lablab
hay and sorghum bran. The objective was to formulate a nutritionally optimal
diet for lactating cows based on low quality but widely available sorghum stover
and farm-produced lablab hay or sorghum bran. The four treatment diets (see
Table 1) were formulated to satisfy the daily nutrient requirements for
maintenance and milk production of lactating dairy cows such as those used in
this trial (NRC, 1978; Crampton and Harris, 1969).
Table 1. Experimental diets
Composition (%, dry-matter basis) Nutrient content (%)
Treatment
Sorghum Lablab
stover hay
Sorghum
bran
Crude
protein
Total digestble
nutrients
Diet 1 60 40 - 10.5 56.3
Diet 2 60 30 10 10.0 58.8
Diet 3 60 20 20 9.5 61.0
Diet 4 60 10 30 9.3 64.1
In diet 1 lablab was mixed with the stover by hand at the time of feeding; in
the other three diets, the sorghum bran was fed separately in split oil-drums. The
animals were provided with ad libitum bonemeal-salt (1:1 w/w ratio) and
vitamins A D and E. The treatments were randomly allocated to each of 40
farmers. Voluntary feed intake was determined in all treatment groups by
measuring the daily refusals over a period of seven days and for a maximum of
six lactating cows per farm. Statistical analysis using the t-test (Snedecor and
Cochran, 1967) was conducted on the performance data obtained from the
lactating cows that completed the trial.
Nutritive value
Three replicate samples of lablab, sorghum stover and sorghum bran were
submitted for laboratory chemical analysis.
Samples of fresh whole plants and plant parts were air-dried (60°C) and
then ground in a Wiley mill (1-mm screen). The dried and ground samples were
stored in air-tight bottles and later analysed for organic matter, crude protein,
356
crude fibre, ash and mineral components according to methods approved by
AOAC (1975) and in vitro dry and organic matter digestibility according to
Tilley and Terry (1963) procedures.
Dairy cattle performance
Each farmer was provided with two calibrated 10-litre plastic milk buckets for
recording milk yield. Milk records were collected and summarised by project
staff at the end of each month.
RESULTS AND DISCUSSION
Fodder legume production and conservation
Average dry-matter yields (t/ha) of lablab by farmers and on the research plots in
1985/86 and 1986/87 are shown on Table 2. Fertiliser application had no effect
(P>0.05) on average dry-matter yields on farmers' plots or on research plots, and
there were no significant differences (P>0.05) in dry-matter yield between
farmers' fields and the research plots. The results from the two seasons were not
greatly different. Low dry-matter yields and lack of fertiliser response could be
due to lower than average rainfall in both seasons.
Table 3 shows the total quantities of lablab dry matter harvested and
conserved by the project farmers during the four years of the project. The higher
lablab dry-matter yields in 1987/88 than in the other three years were attributed
to higher rainfall in the project area (651 mm) in that year. The decrease in the
total quantity of lablab hay harvested by farmers in 1988/89 season, even though
the rainfall was higher than normal, was due to the improved grazing conditions
caused by reasonable rainfall.
Table 2. Average dry-matter yield oflablab hay from project farms and research plots as
influenced by fertiliser application rate
Dry-matter ;yield (t/ha) at fertiliser application rate of
Year Rainfall (mm) 0 kg/ha 100 kg/ha 250 kg/ha
Farmers' plots
1985/86 328 1.23 1.44 -
1986/87 380 1.37 1.49 -
Research plots
1985/86 1.41 1.56 1.70
1986/87 1.47 1.54 1.79
357
Table 3. Lablab dry-matter yields from farmers'fields
Average
-matter yield
0)
Total dry-matter
Mean rainfall
(mm)
dry yield
Year No of farmers CO
1965/86 328 12 1.14 13.1
1986/87 380 30 0.70 21.0
1987/88 651 40 2.82 11Z8
1988/89 565 40 0.87 34.8
The major constraint observed during harvesting and conservation was the
time required to dry the stems. Lablab leaves dry and shatter within three days
but it takes up to six weeks for the stems to dry completely. Various methods of
drying and storage using tripods, stooking on the ground and combing three rows
into one row were tried at Sebele Research Station. Method of drying had no
effect on drying time but the crop was baled more efficiently from stooks and
tripods with minimum dry-matter loss due to leaf shattering, mould or termite
damage. In 1987/88 lablab was dried in rows and baled six weeks after harvest.
Feeding trial (dry season)
There were no differences (P>0.05) in the average daily dry-matter, crude-
protein and energy (TDN) intakes by lactating cows fed the four diets (Table 4).
Table 4. Average voluntary intake ofnutrients by lactating cows
Voluntary intake (kg/day)
DM/100 kg CP/lOOkg
liveweight
TDN/lOOkg
liveweightDiet DM liveweight CP TDN
Dietl 9.43 2.46 0.99 0.26 533 1.39
Diet 2 8.77 2.43 0.88 0.24 5.16 1.42
Diet 3 8.93 2.50 0.85 0.24 5.45 1.52
Diet 4 8.22 2.24 0.76 0.21 5.27 1.48
Diet 1: 60% sorghum stover and 40% lablab hay
Diet 2: 60% sorghum stover, 30% lablab hay and 10% sorghum bran
Diet 3: 60% sorghum stover, 20% lablab hay and 20% sorghum bran
Diet 4: 60% sorghum stover, 10% lablab hay and 30% sorghum bran
Nutritive value
The nutrient composition and in vitro digestibility valves for lablab, sorghum
stover and sorghum bran are shown in Table 5. Lablab contained more crude
358
Table 5. Average nutrient composition of diet components
Composition (% of dry matter)
digestbilities (%)
In vitro
Organic Crude
matter protein Crude fibre AshFeed Ca P DM OM
Lablabhay 90.8 16.4 27.7 9.2 1.68 0.13 59.9 57.1
91.6 6.4 32.5 8.4 0.38 0.10 54.8 49.8
Sorghum
stover
Sorghum grj3 u$ %^ £?
bran
protein and had higher dry-matter and organic-matter digestibilities and calcium
to phosphorus ratios than sorghum stover. The higher digestibility coefficients
are attributed to the higher crude-protein and lower crude-fibre content in lablab
than in sorghum stover. The calcium to phosphorus ratios were within acceptable
limits reported for cattle (NRC 1978). Due to high crude-protein and mineral
contents observed in lablab plants, dry-season diets for lactaung and in-calf cows
were based on sorghum stover supplemented with lablab hay.
Dairy cattle performance
Comparative basic data on dairy cattle performance on-farm are given in Table 6.
Average lactation lengths for Simmental-Tswana cows were longer (P<0.05)
than for Tswana cows in 1985/86, 1986/87 and 1988/89 but similar in 1987/88.
Average daily milk yields per cow were similar within breed but different
between breeds. On average, milk yield per day per cow for both breeds tended
to increase with increasing seasonal rainfall; however, the reason for the low
yield in the high rainfall year 1987/88 is not clear.
On average under similar feeding and management systems, Simmental x
Tswana cows produced twice as much milk as Tswana cows. These results are
comparable with those obtained in on-station trials (APRU 1988).
CONCLUSIONS
The predominant crops in the traditional cropping system of the project area are
sorghum, maize and millet intercropped with cowpea and watermelon. The dairy
project has succeeded in convincing participating farmers to allocate one hectare
of land for lablab fodder production. Fodder production has become a
component of the cropping system.
The dry-season feeding strategy using high protein Lablab purpureus
legume fodder, planted and harvested by farmers and fed in association with crop
byproducts and post-harvest residues, has been a significant intervention in the
small dairy farms.
359
Table 6. Milk production ofSimmental x Tswana and Tswana cows
Item 1985/86 1986/87 1987/88 1988/89
No of fanners 12 30 40 40
No of cows per fanner
Simmental z Tswana 10 15 24 20
Tswana 24 74 140 l11
Lactation length (days)
Simmental z Tswana 273 285 303 262
Tswana 223 202 296 181
Milk yield/cow (kg)
Per lactation
Simmental z Tswana 760 890 818 988
Tswana 338 319 474 420
Per day
Simmental z Tswana 2.8 3.1 2.7 3.8
Tswana 1.5 1.6 1.6 2.3
Rainfall (mm) 328 380 651 565
Fertiliser applications on farm plots as well as on station plots did not show
any significant effect (P>0.05) on lablab dry-matter yield. Lack of response may
be attributed to low seasonal rainfall and distribution.
Chemical analysis showed that lablab contained 2.5 times more crude
protein than sorghum stover (16.4 vs 6.4%). The use of lablab as a protein
supplement in crop stover based diets is the practical approach for the dry-season
feeding of lactating and in-calf cows.
REFERENCES
APRU (Animal Production Research Unit, Department of Agricultural Research). 1979.
Livestock and range research in Botswana. AnnualReport 1979. Government Printer,
Gaborone, Botswana, pp 46-49.
APRU (Animal Production Research Unit, Department of Agricultural Research). 1980.
Ten years ofanimalproduction and range research in Botswana. Government Printer,
Gaborone, Botswana, p. 56.
APRU (Animal Production Research Unit, Department of Agricultural Research). 1988.
Livestock and range research in Botswana. Annual Report 1988. Government Printer,
Gaborone, Botswana, pp. 15-45.
AOAC (Association of Official Analytical Chemists). 1975. Official methods ofanalysis.
12th edition. AOAC, Washington DC, USA.
360
Crampton D W and Harris L E. 1969. Applied animal nutrition. 2nd edition.
W H Freeman, San Francisco, California, USA.
Humphreys LR. 1978. Tropical pastures andfodder crops. Longman, London, UK.
135 pp.
Mosienyane B P. 1983. Crop residues for animal feeding. The Bulletin ofAgricultural
Research in Botswana. 1:3.
Mosimanyana B and Kiflewahid B. 1987. Feeding of crop residues to milking cows in
small-scale farms in Botswana. In: Little D A and Said AN (eds), Utilization of
agricultural by-products as livestockfeeds in Africa. Proceedings of a workshop held
at Ryall's Hotel, Blantyre, Malawi, September 1986. ARNAB (African Research
Network for Agricultural By-products). ILCA (International Livestock Centre for
Africa), Addis Ababa, Ethiopia. pp. 127-135.
NRC (National Research Council). 1978. Nutrient requirements ofdomestic animals,
No 5. Nutrient requirements of dairy cattle. 5th edition. NRC, Washington, DC, USA.
Snedecor G W and Cochran W G. 1967. Statistical methods. 6th edition. Iowa State
University Press, Ames, Iowa, USA. pp. 54—56.
Tilley S M A and Terry R A. 1963. A two stage technique for the in vitro digestion of
forage crops. Journal of the British Grassland Society. 18:104—111.
361
362
SMALL-RUMINANT FEEDING SYSTEMS FOR SMALL-SCALE
FARMERS IN HUMID WESTAFRICA
OB Smith
International Development Research Centre (IDRC)
Regional Office for West and Central Africa
BP 11007, CD Annexe, Dakar, Senegal
ABSTRACT
Although not fully integrated into the crop-farming systems which constitute the
major agricultural activity in humid West Africa, small ruminants play important
economic, cultural and social roles. Of particular interest is their use as a means
of storing wealth in times of agricultural plenty, to provide cash reserves for
emergencies and to guarantee a degree of food security in times of crop failure.
If small ruminants are to continue to play these roles, in addition to improving
the protein nutrition of the population, constraints on productivity must be
alleviated. One of the major constraints is inadequate and fluctuating feed
supply. It is suggested that this results from poor feed management and
utilisation, rather than from absolute shortages.
The major feed resources available are natural pastures, browses and crop
residues and byproducts. The availability and quality of these resources vary, but
evidence is presented to show that when they are properly selected and
combined according to their nutritional characteristics, adequate and productive
diets could be provided all year round, for sustainable small-ruminant production
and productivity. A number of proven feed combinations targeted towards
particular seasons and ecosystems are suggested. Future research activities
required to identify additional feeding systems are highlighted.
RESUME
Systemes d alimentation destines aux petits producteurs d'ovins et de caprins
dans la zone humide d'Afrique de I'Ouest
Bien qu'ils ne soientpas encore pleinement intégres dans la production vegetale,
laprincipale activite agricole de I'Afrique de I'Ouest, les petits ruminants
occupent une place economique et socio-culturelle importante dans cette région.
Plus particulierement, ils constituent en periode d! abondance, une forme
363
d'accumulation des richesses. Celles-ciprocurent des recettes monétaires
permettant de faire face aux situations d'urgence et d'éviter le pire en cas de
mauvaises récoltes. Cela dit, seul un accroissement durable de la productivite de
ces animaux leur permettra de continuer à remplir ces fonctions tout en
contribuant à améliorer I'alimentation proteique des populations. Les
principaux obstacles à I'amélioration de cette productivite sont l'insuffisance et
les fluctuations des ressources alimentaires du betail. Cesproblèmes semblent
dus, non pas à des pénuries réelles, mais à une mauvaise gestion alliie à une
mauvaise utilisation des ressources alimentaires disponibles.
Celles-ci sont constituées defoin de pâturages naturels, de fourrages
ligneux, de résidus de récoltes et de sous-produits agricoles de diverses qualites
produits en quantites variables. Cette étude montre que des choix rationnels et
des combinaisons tenant dûment compte des caracteristiques nutritionnelles de
ces divers aliments pourraient permettre d'offrir aux petits ruminants, d'un bout
à I'autre de I'année, des rations propres à assurer chez ces animaux une
productivite et une production soutenues. Un certain nombre de combinaisons
satisfaisantes ont éteproposées selon les saisons et les écosystèmes. Enfin, des
axes de recherches futures ont éte suggérés en vue de I'identification d'autres
systèmes d'alimentation appropriés.
INTRODUCTION
Humid West Africa is made up of two distinct belts—the lowland, coastal rain
forest and, to the north, the derived savannah belt. Together, they cover a total
land area of 707 000 km , stretching from the lower third of Nigeria to Guinea.
According to Jahnke (1982), annual rainfall in this zone is well over 1500 mm,
and the crop growing season could be 270 days or more. The coastal lowland
forest area contains cultivated farm land and bush fallow which, together with
natural clearings, are often invaded by coarse grasses (Pennisetum spp). These
grasses are sparse or absent under the forest trees that are abundant in this belt
but sparse in the savannah belt, where regular fires have reduced tree cover to
low trees, shrubs and bushes. Fallow areas in the savannah are also covered by
coarse grasses, predominantly Hyparrhenia spp (Atta-Krah and Reynolds, 1989).
Small ruminants are the dominant livestock species in the zone, with an
estimated population of about 14 million (Table 1). The dominant breed of both
sheep and goats is the West African Dwarf. These animals are raised exclusively
for meat, serve as cash reserves for emergencies and guarantee a degree of food
security in times of crop failure. They therefore play an important social and
cultural role for the households and communities that keep them. Small-ruminant
flock sizes in these communities are small, about two to six animals per
household, with goats out-numbering sheep. But large numbers of households
keep small ruminants: figures reported in the literature range from a low of 23 to
a high of 70% of rural households. A large proportion of these animals are owned
and managed by women.
364
Table 1 . Small ruminant and human agriculturalpopulations in humid West Africa
Populations (thousands) Ratios
Small ruminants
Total small
ruminants
Agricultural
humans
per agricultural
Country Goats Sheep Goats:sheep human
C6te d' Ivoire 816 874 1690 1555 0.93 1.08
Ghana 1200 990 2190 4 347 1.21 0.50
Guinea 79 86 165 1104 0.92 0.15
Liberia 190 190 380 1268 1.00 0.30
Nigeria 5621 3476 9097 11955 1.62 0.76
Sierra Leone 59 20 79 1601 2.95 0.05
Togo 45 33 78 233 1.36 0.33
Total 8010 5669 13 679 22 063 1.41* 0.62'
'Means
Source: Jahnke (1982)
PRODUCTION SYSTEMS
Small-ruminant production is just one of several farm activities undertaken in
humid West Africa. Household food needs are met from cereals (maize,
sorghum), root crops (cassava, yam, sweet potato) and food legumes (cowpeas)
which are grown in a bush fallow rotation. Cash needs are met by income from
cultivation of tree crops (cocoa, oil palm, rubber) and fruits (pawpaw, orange,
plantain and banana). Small ruminants and other livestock are rarely integrated
with crop production, and account for a small portion of household expenditures,
but nevertheless make an important contribution to the total economy. This lack
of crop-livestock integration means that crop residues and byproducts are not
systematically and strategically used for livestock feeding, and the potential of
animal waste to improve soil fertility and conservation is not fully exploited.
Perhaps the most common small-scale small-ruminant production system is
that described as the traditional system—a low-input extensive or subsistence
system, based on free grazing of roadside and bush forages complemented with
kitchen wastes (peels of tubers and fruits, cereal brans) and crop residues (cereal
stovers). Another common system of production is the intensive cut-and-carry
feeding of tethered or confined animals, found in densely populated areas where
almost all available land is devoted to cultivation, such as Eastern Nigeria and
Benin Republic. In such densely populated areas, small ruminants are tethered or
confined to protect crops and are therefore hand-fed, albeit with the same feed
resources as in the free-roaming system.
Although the two systems are reasonably efficient in terms of the objectives
and resources of the small-scale farmer (von Kaufman and Francis, 1989), there
365
is room for improvement if major constraints facing the producers can be
alleviated. Identified constraints include a high incidence of disease and pests,
inadequate and fluctuating feed supply, poor husbandry and a lack of effective
extension services (Ademosun, 1988; Atta-Krah and Reynolds, 1989; von
Kaufman and Francis, 1989). This paper mainly addresses the problem of
inadequate and fluctuating feed supply, particularly highlighting ways of
alleviating this constraint through a judicious exploitation of the potential
complementarity of the available feed resources.
AVAILABLE FEED RESOURCES
Feed resources available to smallholder production systems are natural pastures,
browses, crop residues and kitchen wastes.
Natural pastures
Natural pastures grow on uncultivated land to which animals have access for
grazing. They are found along roadsides and on fallow lands in the coastal forest
belt of humid West Africa. They assume more important proportions in the open
derived savannah. According to Atta-Krah and Reynolds (1989), natural pastures
consist of a mixture of grasses such as Imperata cylindrica, Andropogon
gayanus, Pennisetum spp and Hyparrhenia spp. These grasses grow rapidly
during the wet season, becoming fibrous and coarse, and are undergrazed
because of the large amounts that become rapidly available. Their quality
declines further during the dry season when they become standing hay and are
subject to overgrazing.
A review of published nutrient contents of these grasses shows that during
the period of rapid growth (wet season) they contain, on average, about 25% dry
matter, made up of 10% crude protein, 6% ash and a fibre content of 32% crude
fibre or 43% acid detergent fibre (ADF). As the dry season advances and
conditions become harsh, their nutritional quality declines to the extent that
crude protein could fall to as low as 2%. Ash values decline to about 3-4% as a
result of translocation to the root system, while fibre content increases in
response to the process of lignification, sometimes to up to 50% crude fibre or
60% ADF.
In other words, these grasses cannot meet the nutrient requirements of small
ruminants for most the year. Even during the rains they can only satisfy
maintenance requirements. In vitro and in vivo studies carried out to evaluate
these grasses have confirmed this conclusion.
In a recent study in which rumen degradability in sheep, goats and cattle
was used as a screening technique to evaluate the potential nutritive value of
various feed resources, Smith et al (1989) concluded, on the basis of 48-hour
dry-matter degradability in sheep and goats, that because of high cell wall
366
Table 2. Intake and utilisation oftropical grasses by goats
Dry matter
Offered
W-75) Digestible dry-matter
intakeDigestibility
Feed Consumed (%) (g/kg°-75)"
Panicum maximum
(well fertilised,
6 weeks old)
75 54.9 75.8 41.6
P. maximum (hay) 77 43 45 19.4
Cynodon nlemfuensis
(hay)
87.5 40.6 43.2 17.5
C. nlemfuensis (hay) 131.5 39.9 46.6 18.6
* NRC (1981) maintenance requirement for goats is 27 g digestible organic matter intake/kg per
day, ie, about 30 g digestible dry matter intake/kg ' per day, assuming 10% ash
Source: Ademosun et al (1988)
contents during the dry season, the quality of grass forages such as Pennisetum
and Andropogon spp may be too low to sustain the animals. Supplementation
with browse or crop residues was recommended.
Data from Ademosun et al (1988), summarised in Table 2, confirm the
suggestion that unless well fertilised, and harvested young, tropical grasses alone
cannot supply small ruminants with the nutrients required for a reasonable
production level. The production of high quality forages requires inputs and
management know-how not yet available to the small-ruminant producers within
the farming system described above. Other readily available feed resources must
therefore be used to complement the forages. Fodder trees and shrubs (browses)
can apparently fulfil this role.
Browses
Browses, in the form of fodder trees and shrubs, form an integral part of farming
systems in humid West Africa (Atta-Krah et al, 1986). As their establishment and
management require little effort, labour, time, technical know-how or resources,
it should be easy to promote and intensify their use as animal feed. The multi
purpose nature of browses as fuel wood, shade, food (fruits), poles, etc, as well
as their potential to improve soil fertility and conservation, are added incentives.
In terms of utilisation as animal feed, browses currently play an important,
albeit non-strategic, role, as animals under confinement often receive one type or
another of browse, from fallow lands or around homesteads. Efficient utilisation
in a complementary way with grass forages and crop residues is what needs to be
worked out through research, in order to exploit their potential nutritive value.
Data in the literature demonstrate the potential complementarity between
browses and grass forages. The nutrient contents of some common browses,
367
shown in Table 3, indicate that, on average, browses contain more crude protein
and organic matter, but less fibre, than tropical grasses, and should, therefore,
increase nutrient supply to the animal when combined with the poorer quality
forage. Rumen degradability studies by Smith et al (1989) and others (Minor and
Hovell, 1979; Kabaija, 1985) show that many browses degrade fairly well and
rapidly (Table 3), supplying much needed soluble carbohydrates and fermentable
nitrogen to the rumen, thus enhancing forage breakdown. Many of these browses
contain high levels of essential elements such as calcium, sodium and sulphur, as
well as critical microelements such as iron and zinc (Kabaija and Smith, 1989;
Devendra, 1990), which have been shown to be deficient or borderline for
productive purposes in many tropical grasses (Olubajo, 1974; Kabaija and Smith,
1987). Moreover, most of the browses remain green all year round and, if
properly managed, continue to provide substantial amounts of foliage even
during the dry season. Browses, therefore, complement grasses both
quantitatively and qualitatively. Several feeding and growth trials have
confirmed the potential of browses to enhance forage utilisation and improve
performance.
In long-term studies designed to evaluate the effects of browse
supplementation on the productivity of sheep (Reynolds and Adediran, 1987)
and goats (Reynolds, 1989), pregnant ewes and does maintained on a basal diet
oiPanicum maximum were supplemented with graded levels of a 1:1 (w/w)
mixture of Gliricidia sepium and Leucaena leucocephala over two reproductive
cycles. Browse supplementation increased growth rate to weaning of both kids
and lambs by 45%. When the effect of direct supplementation to the kids and
lambs was examined, browse supplementation doubled growth rate from birth to
six months in both species. It was also observed that browse supplementation
increased overall daily dry-matter intake by the dams during the final two
Table 3. Nutrient contents and rumen degradabilities ofsome common browses
% Dry matter
Dry
matter
Acid Dry-matter
digestibility
Half life
Dry matter
(hours)
Nitrogen
Crude
protein
detergent Crude
fibreBrowse (%) fibre Ash (%)
Bamboo
leaves
27.3 21.0 47.9 28.2 11.0 36.6 - -
Cassava
leaves
23.8 23.0 29.8 17.4 3.5 84.3 13.1 20.5
Gliricidia
leaves
23.5 28.4 29.4 20.7 9.7 75.7 12.0 7.9
Leucaena
leaves
24.0 30.0 33.8 31.7 8.8 70.0 23.2 21.2
Sources: Minor and Hovell (1979); Kabaija (1985); Ademosun et al (1988); Smith et al (1989)
368
months of pregnancy and four months of lactation. Aproductivity index
calculated as weight of offspring weaned/dam per year increased by 0.64 kg in
goats, and 1.41 kg in sheep.
Recently, Ademosun et al (1988) reported that in a series of feeding trials
with goats, results from preliminary experiments suggested that tropical grasses
alone could not provide stall-fed goats with the nutrients required for reasonable
production levels. Therefore, in subsequent trials they evaluated the effect of
supplementing these grasses with two common browses, Gliricidia and
Leucaena. The results, summarised in Table 4, demonstrate the potentials of
these browses to improve the utilisation of poor quality forages. Follow-up
studies were designed to investigate the potential of these browses as sole feeds,
a feeding system that could be particularly valuable during the dry season when
there is an acute shortage of conventional forages. Table 5 summarises some of
the results obtained.
All of these studies suggest that the use of browses, such as Gliricidia and
Leucaena, either as supplements to tropical forages or as sole feeds, is a viable
feeding system in humid West Africa. The spectre of dihydroxypyridone (DHP)
toxicity in the case ofLeucaena should not be a deterrent, as evidence exists that
rations containing up to 50% by weight oiLeucaena constitute no hazards to
sheep and goats (Ademosun, et al 1988).
Crops residues and kitchen wastes
As indicated above, an important component of the farming system in humid
West Africa is the cultivation of various crops—food crops (maize, sorghum,
Dry matter Digestible dry matter
43.1 19.4
51.1 233
58.7 30.0
69.1 37.9
48.3 22.9
50.8 20.2
66.1 34.4
68.4 326
Table 4. Complementarity oftropicalforages and browses
Intake (g/kg0.75 per day)
Feed combination
Panicum maximum hay ad libitum
Panicum maximum hay ad libitum plus
10 g GUnddia/kg"15
20 gGIiriddia/kgaj5
30 gGtiricidiaJkg0-75
Panicum maximum hay ad libitum
Panicum maximum hay ad libitum plus
10 g Leucaena/kg '
20 g Leucaena/kg '
30 R Leucaena/kg '
Source: Adapted from Ademosun et al (1988)
369
TableS. Leucaena and Gliricidia as sole feed for goats
Proportion
Intake (g/kg ' per day)
consumed Total Digestible
(%, dry-matter dry dry
Feed combination basis) matter matter
Panicum maximum (hay) 100 43.1 19.5
Gliricidia sepium 100 66.7 37.9
Gliricidia sepium 65
plus 70.9 42.3
Leucaena leucocephala 35
Gliricidia sepium 36
31
33
plus
Leucaena leucocephala 70.1 49.6
plus
Cassava
Panicum maximum 20
plus
Concentrate 80
77 55
%of
Growth rate optimum
(g/day) growth rate
23.3
36.0
43.5
60
39
60
73
100
Source: Adapted from Ademosun et al (1988)
cassava, plantain) or tree crops (cocoa, oil palm, rubber). Many of these crops
undergo primary processing, either at the homesteads or farmsteads, thus
producing a substantial amount of crop residues. Unlike browses, which tend to
have medium to high nutritional values and hence complement poor quality
forages, the nutritional value of crop residues could vary from high to low levels,
similar to those of poor quality forages.
Many crop residues are low in protein, are highly fibrous and, therefore,
low in fermentable carbohydrates. Such feeds fail to maintain an efficient rumen
ecosystem for their own degradation and/or that of equally poor forages.
Theoretically, but also from practical observations, it has been suggested that the
characteristics of a maintenance diet for adult ruminants are a crude-protein level
of 6-7%, a dry-matter intake of about 1.7% of body weight and a dry-matter
digestibility of 50-55% (Devendra, 1985). Table 6 shows that many crop
residues rarely meet these requirements. Such residues may require upgrading by
chemical, physical or biological treatments to improve their value and
usefulness. Such treatments may, however, not be economically suitable for
small-scale small-ruminant production systems in humid West Africa.
Whereas crop residues (cereal straws, stovers) may not be suitable as
supplements to poor quality forages, they could be used as basal feeds,
supplemented with better quality feed materials such as browses. Evidence exists
370
Table 6. Voluntary dry matter intake and digestibility ofselected crop residues
Crude
Intake as % of body
weight
Dry-matter digestibility
(%)
protein
Crop residue (%) Sheep Goats Sheep Goats Sources
Maize stover 4.0 - 0.7 - 53 1
Sorghum stover 4.0 - 20 - 57 1
Rice straw 4.2 1.4 1.9 47 48 2
Cocoa pods 5.0 - - 20 - 3
Dry-matter intake
(gteg0.75 per day)
Growth rate
(g/day)
78.5 56.3
74.8 55.0
67.3 50.0
Sources: 1. Alhassan et al (1984); 2. McManus et al (1972); 3. Smith and Adegbola (1982)
Table 7. Performance ofgoats fed on crop residues supplemented with browses
Basal diet*
Corn stover
Sorghum stover
Sugar-cane tops
* All three diets supplemented with groundnut haulms, cassava tops andLeucaena leaves
Source: Soedomo-Reksohadiprodjo (1985)
in the literature (Table 7) that a feeding system consisting of fibrous crop
residues supplemented with browses is a viable one.
Other crop residues could, nevertheless, be used as supplements in feeding
systems based on poor quality forages, because of their fairly high nutritive
values. Such residues as roots and tuber peels, cereal brans and grain legume
brans supply a fairly high amount of much needed soluble carbohydrate and
fermentable nitrogen to the rumen. The potential feeding value of this category
of crop residues is demonstrated in Table 8.
Table 8. The value ofsun-driedpeels as supplements to poor quality tropical forage for sheep
Dry-matter intake Weight gains Dry-matter digestibility
Diet' (kg/day) (g/day) (%)
70% Pennisetum purpureum
35% Pennisetum purpureum
plus 35% Cassava peels
70% Cassava peels
* All diets supplemented with cottonseed cake
Source: Fomunyam and Meffeja (1987)
0.87 45.2 50.7
1.36 106.7 79.0
1.06 227.1 88.1
371
In other words, in order to maximise the feed value of crop residues in
humid West Africa, researchers need to investigate this nutritive-value-based
dichotomy, and classify these materials into potential supplements to forages or
browses, and potential basal feeds that require supplementation with browses.
Table 9 shows such a classification for some crop residues available in the forest
belt of humid West Africa. The classification based on crude-protein and fibre
(ADF or NDF) contents and in-situ degradability will facilitate the formulation
of feeding systems that maximise the use of available feed resources.
Table 9. Nutritional role of common crop residues in humid WestAfrica
Crop residue Acid detergent
%DM
degradability
In situ
classification Crude fibre fibre Crude protein (%DM)
Basal feeds
Rice straw 20-45 45-55 2-9 30-34
Cocoa pods 20-45 55-59 2-8 38-40
Sugar-cane tops 28-34 43 5-8 10-20
Sorghum stovers 31-35 45-50 3-6 25-30
Corn stovers 28-46 46-50 2-8 50-65
Supplements
Cassava peels 10-22 15-18 3-7 70-75
Yam peels 5-8 10-12 5-8 75-S0
Sweet potato peels - 15-18 6-10 80-90
Cowpea husk 40-45 38-40 6-10 70-75
Maize bran - 8-10 15-20 75-80
RECOMMENDATIONS
From the foregoing, it is clear, that a number of feasible feeding strategies exist.
In order to exploit available resources, the choice must be guided by season,
number of animals to be fed, available resources and ecological zone. The
suggested systems shown in Table 10 have been guided by these factors as well
as by research results discussed above.
The list of suggested feeding systems in Table 10 is by no means
exhaustive, and many more could be added as a result of current and future
research results. Some of the pressing future research needs which have high
potential pay-offs include:
• characterisation through nutritional studies of the role of various crop
residues and kitchen wastes as supplements or basal feeds within particular
feeding systems
372
Table 10. Suggestedfeeding systems for small ruminants in humid West Africa
Feeding system Target belt Target season
Forage based
Forage plus browse Forest, Savannah Wet
Forage plus browse plus crop residues Forest, Savannah Wet
Forage plus highly fermentable crop residues Forest, Savannah Wet
Browse based
Browse alone Forest, Savannah Dry
Browse plus fermentable crop residues Forest, Savannah Dry
Crop-residue based
Fibrous crop residues plus browse Forest, Savannah Dry
Fibrous plus fermentable crop residues Forest, Savannah Dry
Novel systems
Under-tree crop grazing plus supplement Forest Wet
Alley farm foliage plus crop residue Forest Dry
Fodder banks Savannah Dry
• nutritional evaluation of local browse species. The advantages of promising
local species over introduced species such as Leucaena, in terms of farmer
adoption, are obvious
integration of small ruminants into the alley farming concept, particularly
working out the proportion of foliage to be recycled directly as mulch, or
indirectly through animal faeces, in order to ensure sustainability
• development of small-scale producer-targeted technology for making forage
silages. Such technology would involve no more machinery than a hand-run
chopper and no additives other than forages, crop residues or browses rich
in fermentable carbohydrates and nitrogen
integration of small ruminants into tree-crop production
• adaptation of the fodder bank concept to small-ruminant production.
CONCLUSIONS
Efforts to alleviate current constraints of inadequate and fluctuating feed supply
to small ruminants in humid West Africa should be directed primarily toward a
proper knowledge of the nutritional characteristics of various feed resources
available in order to fully exploit the natural complementarity that exists
between them. Current feed management and utilisation practices also need to be
examined critically, in order to identify those that maximally exploit the
nutritional potential of the feed resources.
373
For example, farmers keeping small ruminants in the forest belt of humid
West Africa feed crop residues and kitchen wastes such as cassava peels, maize
bran and cowpea husks to their animals first thing in the morning, before turning
the them out to graze fibrous grasses all day. Results of rumen degradability
studies suggest that this system should be the other way round, with the rapidly
degraded peels, brans and husks fed late in the afternoon and at night, to better
synchronise the release of the energy and nitrogen they contain with those of the
less rapidly degraded grasses. This thesis needs to be verified on-farm.
The abundant, lush and nutritive roadside and fallow land grasses during the
rains are currently underutilised. This resource needs to be preserved as silage
for dry-season feeding. The challenge to researchers is to develop an ensiling
technology harmonious with the resources of the small-scale producers.
Feed constraints currently limiting small ruminant production and
productivity in humid West Africa are, to a large extent, due to a non-strategic
utilisation and combination of available feed resources, to develop production
feeding systems, rather than absolute quantitative and qualitative shortages.
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376
SOCIO-ECONOMIC AND POLICY ASPECTS OF USING CROP
RESIDUES AND AGRO-INDUSTRIALBYPRODUCTS AS
ALTERNATIVE LIVESTOCK FEED RESOURCES IN NIGERIA
G BAyoola andJA Ayoade
University of Agriculture
PMB 2373, Makurdi, Nigeria
ABSTRACT
Nigeria has an immense capability to produce many different types of crop
residues and agro-industrial byproducts which could be used to improve
livestock nutrition. However, for various socio-cultural and policy reasons,
farmers are not making use of these resources at present.
A model feeding trial demonstrates the profitability of the use of
non-conventional feed resources, and suggestions are made for policy
interventions in areas of preservation and treatment, transportation, extension
and research.
RESUME
Aspects socio-économiques et stratégiques de l'utilisation des résidus de
récolte et des sous-produits agro-industriels dans I'alimentation des animaux
d'élevage au Nigéria
Compte tenu de ses énormes potentialités en la matiere, le Nigéria pourrait
produire un grand nombre de résidus de récolte et de sous-produits
agro-industriels propres à servir d'aliments du betail. Malheureusement, les
paysans ne s' intéressent guère aujourd'hui à ces ressources et ce, pour diverses
raisons y compris des raisons d'ordre socio-économique et stratégique.
Un régime alimentaire modèle expérimenté dans le cadre de cette etude a
cependant permis de mettre en évidence les avantages économiques de
I'utilisation de ces ressources alimentaires non conventionnelles. Enfin, des
interventions stratégiques appropriees ont eté recommandées en vue de
promouvoir la conservation, le traitement, le transport et la vulgarisation des
résidus de récolte et des sous-produits agro-industriels ainsi que la recherche
dans ce domaine.
377
INTRODUCTION
Large quantities of crop residues, produced on private and government farms in
Nigeria, are wasted year after year. Some are left to rot in the fields, which may
improve soil fertility, but most are burned. Similarly, most agro-industrial
concerns in the country dispose of their valuable byproducts in non-beneficial
ways. Although there is much evidence that livestock fed crop residues and
agro-industrial byproducts can achieve substantial weight gains (eg, Ward, 1978;
O' Donovan, 1979), a recent survey in Benue State, Nigeria, (Ayoade and Ayoola,
1991) shows that, on average, more than 60% of livestock farmers are not aware
of the value of crop residues in animal nutrition.
Recently there has been a growing policy recognition of the role of non-
conventional feed resources in livestock development. Following the acute
shortage of foreign exchange for importing concentrates in the structural
adjustment period, the government has set up a task force to investigate and
advise on the prospects and possibilities of using the alternative livestock feed
resources available in the country. This paper examines some aspects of the use
of crop residues and agro-industrial byproducts in livestock production.
AVAILABILITYAND UTnJSATION
A general knowledge of the availability and utilisation of crop residues and
agro-industrial byproducts in the various agro-ecological zones of Nigeria is
important for assessing the potential of these resources.
The agricultural economy of the southern part of Nigeria is largely based on
tree crops; ruminant production is a secondary activity, mainly because of the
tsetse fly menace. The forest is principally exploited for wood, rubber and palm
oil; secondary crops include cocoa, coffee, citrus, banana and plantain. Towards
the north, more land is available for arable farming. Swampy rice thrives in the
delta areas, particularly in River and southern Bendel States, while yam, cassava,
cereals and legumes are abundant in the rest of the southern zone, including
Anambra, Imo, Ondo and the southern part of Oyo State. Thus the crop residues
available in this zone are immense quantities of cocoa pods and cassava and yam
peels as well as enough cereal straws and legume haulms to sustain the local
livestock population during the dry season.
The savannah middle belt (covering northern Oyo, Kwara, Benue, Niger,
Plateau, and the southern fringes of Kaduna and Gongola States) operates an
active grains economy. Arable farming thrives with crops like soybean, maize,
upland and fadama rice, sugarcane, sorghum, yam and millet. These are usually
cultivated in homesteads together with livestock—mainly goats and poultry,
although sheep and cattle are also kept. Cattle rearing generally involves Fulani
agropastoralists who move progressively southwards into this zone in the dry
season. Sedentary and semi-settled Fulanis can also be found interspersed in the
zone with small farms around their houses, integrated with cattle, sheep, goats
378
and poultry (Nuru, 1989). Thus the savannah middle belt produces large amounts
of rice straw, maize stover, millet/sorghum stover, soybean straw and yam peels
as the main residues from cropping activities.
The ecology of the far north, in Kano, Sokoto, Kaduna, Katsina and Borno
States, supports valuable crops such as cotton, wheat, groundnut, millet, sorghum
and cowpea. The area is somewhat arid, but there is a vast expanse of land for
arable cropping without the need to fell trees. This zone has great potential to
supply large quantities of groundnut haulms, wheat stover, cowpea haulms and
millet/sorghum stover. It also sustains a large population of ruminant animals;
transhumance of cattle Fulanis is prominent in addition to homestead rearing of
ruminants and poultry.
Nigeria has numerous small-, medium- and large-scale agro-industrial
concerns, and hence an immense capability to supply agro-industrial waste
materials to agriculture. For example, the brewing industry serves as an
important source of brewers' wastes for feeding livestock.
Although crop residues are widely available throughout the country, their
use as livestock feeds is limited to the northern zone. On the other hand, the use
of industrial byproducts is only popular in the south, among pig owners who
obtain brewers' waste direct from nearby breweries. Treatment of these products
to enhance nutrient intake and availability is not common in the country as a
whole, although recently some attempts to introduce this technology have been
made by the National Livestock Development Project and Agricultural
Development Projects.
SOCIO-CULTURALDIMENSIONS
Table 1 shows a profile of livestock farmers in Benue State (Ayoade and Ayoola,
1991). Most livestock owners are of an age when their physical and mental
abilities limit their involvement in business activities; older people cannot invest
in crop residue sourcing, preservation and treatment on their own, without the
help of their children, but children are often away in urban centres, at school or
working. So most crop residues are left in the fields after the harvest. In addition,
the level of literacy is too low to facilitate efforts of extension agents to
introduce crop residues and byproducts into the farmers' animal nutrition
practices; most farmers have had no schooling. Also, many small farmers keep
livestock for reasons other than cash income, for example, for ceremonies or
simply as a hobby. Such farmers may be unwilling to spend money on acquiring,
preserving and treating crop residues or byproducts.
Ayoade and Ayoola (1991) also found that livestock production at the
household level is mainly the work of women. But according to other surveys in
Benue State (Akpaiyo, 1991; Unaji, 1991), women's production capabilities are
greatly limited by socio-cultural factors. For example: sheep and pig rearing is
believed to reduce women's fertility and cause human infant mortality;
ownership of cattle by women is forbidden by the gods, who could punish
379
Table 1. Selectedfeatures oflivestock producers in Benue State, Nigeria, 1989
Frequency (%)
Age (n=72) <20 0.3
21-40 36
41-60 52
>60 12
Literacy level (n=740) No schooling 78
Adult education 2
Primary school 14
Secondary school 5
Post-secondary school 1
Objectives (n=81) Money 51
Money and ceremonies 37
Ceremonies 5
Hobby 8
Source: Ayoade and Ayoola (1991)
defaulters; and certain animals are associated with witchcraft. As a result,
livestock production is generally low, and so there is only limited demand for
crop residues and agro-industrial byproducts in farm activities.
The last socio-cultural factor to be considered is the transhumance of Fulani
agropastoralists. At the onset of the dry season these people move south in search
of greener vegetation, and thus use grasses and harvested cereal straws in situ to
feed their animals. Preservation of crop residues is not a priority for them
because they move north again when the rains start.
Extension efforts to develop the use of crop residues and agro-industrial
byproducts in livestock production need to take into account these socio-cultural
factors. For example, taboos associated livestock keeping need to be overcome;
agropastoralists could be encouraged to settle; the profitability of crop-residue
use in animal production could be demonstrated, especially to farmers who keep
animals only for ceremonial or hobby reasons. Such efforts may increase the
numbers of ruminants kept by household which, in turn, may enhance the use of
crop residues and industrial byproducts for their nutrition.
ECONOMIC AND POLICY CONSIDERATIONS
Profitability assessment
In order to demonstrate the profitability of enhanced livestock nutrition, a
feeding trial was conducted at Makurdi. Two-year old Bunaji and Gudali feeder
380
cattle, weighing 200 kg, were fed crop residues supplemented with
agro-industrial byproducts (cottonseed cake (CSC), brewers' dried grains (BDG)
and molasses) for 120 days. Health precautions taken during the fattening period
included deworming, tick bathing and vaccinations according to standard
recommendations.
During the first two weeks in the stall, each animal was given 3 kg crop
residue, 1 kg BDG, 1 kg CSC and 1 kg molasses daily. After two weeks, each
animal was given 5 kg crop residue, 2 kg BDG, 1.5 kg CSC and 2 kg molasses
daily. The animals were fed twice a day, half the daily allowance being given at
each meal. The supplements were well mixed before administration, and clean
water and salt licks were available ad libitum.
Adaily weight gain of 0.67 kg was achieved. Details of costs and returns on
live and slaughtered animal bases are summarised below.
Liveweight basis
Naira
Income from sale of two finished feeders at
Naira 10/kg liveweight (finished weight = 280 kg) 5600
Less variable costs:
2 feeder cattle at Naira 1000 each 2000
480 kg BDG at Naira 0.75/kg 360
360 kg CSC at Naira 0.80/kg 288
240 kg molasses at Naira 1.5/kg 360
1200 kg crop residue at Naira 0.20/kg 240
5 Salt licks at Naira 30 each 150
Medication at Naira 50/animal 100 3498
Gross margin 2102
Slaughtered basis
Naira
Income from slaughtering and processing
of two finished feeders:
Lean meat (2 x 100 kg) at Naira 20/kg 4000
Bone meat (2 x 15 kg) at Naira 15/kg 450
Offals (2 x 10 kg) at Naira 15/kg 300
Tails (2) at Naira 60 each 120
Skins (2) at Naira 150 each 300
Heads (2) at Naira 100 each 200
Shanks (2 x 4) at Naira 30 each 240 5610
Less variable costs 3498
Less processing/slaughter cost (Naira 50/animal) 100
Gross margin 2012
381
The cattle fattening enterprise is profitable on both liveweight and
slaughtered bases and so farmers adopting the use of residues and byproducts
would be assured of substantial returns to labour and management. Proper
management practices such as cooperative sourcing of animals, crop residues,
byproducts and medication, would lead to even higher gross margins.
It appears that economic reasons alone cannot explain the observed limited
uses of these feed materials in the livestock industry. The possibility exists,
therefore, for livestock extension services to make an impact in this regard
among the livestock farming population.
Inhibitory policy environment
The national agricultural policy has provisions for encouraging livestock farmers
to "practise various forms of fodder conservation techniques" and to "ensure the
proper utilisation of all agro-industrial byproducts and crop residues which are
found to be suitable for livestock feeding". However, few practical efforts have
been made to apply these policy intentions (FMAWRRD 1988).
There are three observable features of the livestock policy environment that
inhibit the use of crop residues and industrial byproducts in Nigeria. First,
agro-industries are generally not located in the same areas as the main livestock
population. Therefore byproducts which accumulate in the industrial areas
cannot be distributed to livestock owners at the time, and in the form and
quantities, desired, without incurring excessive transport costs. For example, the
Savannah Sugar Company at Numan and the Nigeria Sugar Company at Bacita
are located far from areas of livestock concentration such as Kaduna, Kano and
Sokoto States, and there are no railway links for easy haulage. Furthermore, the
distribution of breweries is skewed toward the south of the country whereas the
greatest population of ruminant livestock is located in the north. This constraint
could be overcome by the development and use of suitable means of treatment,
preservation and transport of the byproducts.
Second, little or no effort has been made to demonstrate to farmers the
advantages of using crop residues and agro-industrial byproducts in livestock
production. This is a part of the observed laxity of livestock extension in general.
The Nigerian agricultural extension system is largely biased towards crop
production, and so what is needed is a complementary extension effort in the
area of livestock production to enhance understanding of sourcing, handling and
utilising crop residues in animal nutrition, particularly under the prevalent mixed
farming systems in the country. The current proposal for unifying agricultural
extension systems should pay attention to this area. This new effort should
incorporate the use of proven extension methods, such as demonstrations,
training, visits and adaptive research activities.
Third, the tempo of research on crop residues and byproducts appears low
in the country. Research needs to be conducted on such issues as nutrient quality
of available residues and byproducts, treatment methods and feeding trials. The
382
economics of crop residue and byproduct utilisation also requires intensive
analytical investigations to formulate least-cost rations for animal nutrition.
There are plenty of opportunities for a concerted research effort to raise and
utilise the potential of these materials.
REFERENCES
Akpaiyo N. 1991. Factors affecting women's performance in livestock production among
Tiv people: A case ofTsambe district. Department of Animal Production, University of
Agriculture, Makurdi, Nigeria. 36 pp.
Ayoade J A and Ayoola G B. 1991. A survey ofsmallholder livestock production in Benue
State, Nigeria. Department of Animal Production, University of Agriculture, Makurdi,
Nigeria.
FMAWRRD (Federal Ministry of Agriculture, Water Resources and Rural Development).
1988. Agriculturalpolicy for Nigeria. Government Press, Lagos, Nigeria. 65 pp.
Nuru S. 1989. Research and development in pastoral production in Nigeria. In: Gefu J 0,
Adu I F, Lufadeju E A Kalian M S and Awogbade M 0 (eds), Pastoralism in Nigeria:
Past, present andfuture. Proceedings of a national conference on pastoralism in
Nigeria, held at NAPRI, Shika-Zaria, Nigeria, 26-29 June 1988. NAPRI (National
Animal Production Research Institute), Ahmadu Bello University, Zaria, Nigeria. pp.
52-69.
O' Donovan P B. 1979. Fattening crossbred and zebu cattle on local feed and by-products
in Ethiopia. WorldAnimal Review 30:23-29.
Unaji G. 1991. Role of women in livestockproduction and marketing in Benue State of
Nigeria: A case study ofOkpokwu Local Government Area. Department of Animal
Production, University of Agriculture, Makurdi, Nigeria. 58 pp.
Ward J K. 1978. Utilization of corn and grain sorghum residues in beef cow forage
systems. Journal ofAnimal Science 46:839.
383
384
COMPARING COSTS ASSOCIATED WITH THE UTILISATION
OF CROP RESIDUES AND PLANTED PASTURES IN
SMALLHOLDER PRODUCTION SYSTEMS IN THE
HIGHLANDS OF HAI DISTRICT, TANZANIA
NS YMdoe, GIMlay andNA Urio
Sokoine University of Agriculture
PO Box 3007, Morogoro, Tanzania
ABSTRACT
This paper discusses the costs associated with the utilisation of crop residues and
planted pastures as major animal feed resources in smallholder production
systems in the highlands of Hai District, Tanzania. The quantitative effects of
changes in transportation costs and prices of concentrate supplements on the
profitability of using crop residues and planted pastures are illustrated using
linear programming models. The costs associated with the use of planted
pastures are lower than those associated with the use of crop residues obtained
from maize and bean farms in the lowland zone, especially in the long term. And
the difference becomes greater as transportation costs and prices of concentrate
supplements increase.
RESUME
Comparaison des coûts associés à l'utilisation des résidus de récolte et des
culturesfourragères dans les systèmes de la petite exploitation dans le district
de Hai en Tanzanie
Cet article est consacré à une analyse des coûts associes à I'utilisation ans
sous-produits agricoles et des cultures fourragères en tant que principales
sources d'aliments du betail dans les systèmes du petit élevage des hauts
plateaux du district de Hai en Tanzanie. Des modèles de programmation linéaire
ont servi à illustrer les effets quantitatifs des variations des frais de transport et
des coûts des concentrés sur la rentabilité des résidus de récolte et des cultures
fourragères. Dans les plaines, les coûts associes aux cultures fourragères sont
inférieurs à ceux relatifs aux résidus des cultures de mais et de haricot
notamment à long terme. Cette différence se creusait avec I'accroissement des
frais de transport et du prix des concentrés utilisés comme complements.
385
INTRODUCTION
Smallholder production systems based on crop growing combined with stall-fed
crossbred dairy cows have been successfully developed in the highlands of Hai
District, Tanzania. Increased population pressure has resulted in progressively
smaller agricultural holdings and grazing land has been taken for perennial
crops, especially coffee and banana. Lack of grazing land has induced most
smallholder farmers to resort to using crop residues from the lowland zone and
established pastures from the highlands as major animal feeds. The most
common crop residues are maize stover and bean straw. Planted pastures include
elephant grass (Pennisetum purpureum), setaria (Setaria anceps), Guatemala
grass (Tripsacum laxum) and Desmodium spp.
Various projects have been initiated to improve feed resources for small
farmers in Hai District. For example, the Integrated Dairy Development
Programme, financed by FAO (Food and Agriculture Organization of the United
Nations), was started in 1985. One of its objectives was to improve feeding of
dairy cattle by helping smallholder farmers to grow improved pastures on their
own land, and by improving the nutritional value of crop residues. Another
project, the Dairy Feeding Systems project, financed by the International
Development Research Centre of Canada, was started in 1984. Phase I of this
project, carried out between 1984 and 1987, concerned developing feeding
packages based on maize stover, bean straw and molasses-urea, and these
feeding packages have been adopted by many smallholder farmers in the
highlands (Mdoe and Mlay, 1990). While continuing with the activities of phase
I, phase II of the project has put more emphasis on developing planted pastures
in smallholder farmers' plots in the highlands.
There are problems associated with both categories of feed resources that
the above projects are attempting to improve. Crop residues must be transported
from maize and bean farms in the lowland zone to the homesteads in the
highland zone. Furthermore, crop residues have low nutritive value, and so must
be supplemented with high levels of concentrates. Establishment of pastures, on
the other hand, is constrained by scarcity of land; most of the land is already
under coffee/banana. However, if the costs of establishing pastures are compared
with those of using crop residues from the lowland zone, it might be less costly,
in the long term, for the farmer to use some land for pasture establishment rather
than depend on crop residues.
Feed accounts for a large proportion of the total cost of dairy production, so
the profitability of smallholder milk production can be increased if farmers could
use low-cost feed resources that provide the required nutrients.
This paper discusses the costs associated with utilising crop residues from
the lowlands and planted pastures in the highlands in Hai District. It then
assesses the impact of changes in transport costs and prices of concentrate
supplements on the profitability of using these feed resources, based on results of
linear programming models developed by Mdoe (1985).
386
COSTS CONSIDERED
Beinerlein (1986) categorises costs into explicit and implicit costs. Explicit costs
are cash costs incurred when inputs are purchased for production and these costs
are directly determined as the money outlay required to obtain inputs. Implicit
costs are costs which do not involve direct payment; they include unpaid family
labour, depreciation and opportunity cost of resources.
Implicit costs are difficult to quantify (Osbura and Kenneth, 1982). Even
so, they must be considered in estimating costs of production; if they are not,
such estimates tend to be understated. Implicit costs considered in this paper are
the opportunity costs of resources; opportunity cost is expressed as the return a
resource can earn when put to its best alternative use.
COSTS ASSOCIATED WITH UTUJSATION OF CROP RESIDUES
Major costs incurred by smallholders in using crop residues as animal feed in the
highlands of Hai District include transport costs, upgrading costs and the
opportunity cost of removing crop residues from farms in the lowlands.
Transport costs
Crop residues have to be transported from maize and bean farms in the lowlands
to the highlands where animals are stall-fed. The bulkiness of the crop residues
and lack of transport constrain the utilisation of crop residues. Modes of
transporting the crop residues include carrying them on the head, bicycles and
vehicles, especially pick-ups. Because hiring pick-ups is a common practice in
the area, rising fuel prices and/or shortages of vehicles and spare parts will lead
to increasingly high costs of transporting crop residues.
Baling crop residues to reduce their bulk and hence increase the quantity
that can be transported could be a way of reducing transport costs. Baling is
expensive for individual smallholder farmers, because of the equipment required
and the need to bale large quantities to achieve economies of scale. Baling could,
however, be carried out on a cooperative basis. Several large-scale farms in
Kilimanjaro and Arusha already bale maize stover and bean straw and sell the
bales to smallholder farmers.
Costs of upgrading crop residues
Crop residues are characteristically low in protein and high in fibre and lignin.
As a result, digestibility is slow, rate of passage is low and voluntary intake is
limited. Intake and digestibility of the crop residues could be improved by
chopping, chemical treatment or supplementation with concentrates or molasses/
urea (Kategile et al, 1981; Kiflewahid et al, 1983; Wanapat and Devendra, 1985).
387
There has been great variation in the extent to which these methods have been
practised by smallholder farmers in the highlands of Hai District. The major
limiting factor to the adoption of a particular method is the cost involved.
Chopping
Many smallholder farmers in the highlands of Hai District chop stover in order
to reduce bulk, increase consumption and reduce wastage. The major drawback
is availability and cost of choppers to individual smallholder farmers.
Chemical treatment
FAO started trials on chemical treatment of maize stover in Hai District in 1987.
These trials were followed by a small-scale residue treatment campaign in 1988.
However, this practice has not been adopted by smallholder farmers, mainly
because of lack of availability and high cost of chemicals.
Supplementation with concentrates
The commonest concentrate supplements used in Hai District are cottonseed
cake, wheat bran/pollard and maize bran. Smallholder farmers usually buy
concentrates from cooperative societies in their villages. The cooperative
societies procure and transport the concentrates from the Tanzania Farmers
Association, the Kilimanjaro Native Cooperative Union and/or private traders in
Moshi and Arusha. This arrangement is very beneficial and popular with
smallholder farmers, but it sometimes fails, especially when concentrates are in
short supply and the farmers have to buy them from other sources.
Shortage of concentrate supplements is a serious problem, not only in Hai
District but throughout Tanzania. And shortages lead to frequent price rises. For
example, the price of cottonseed cake increased by more than 400% between
1984 and 1990. For this reason concentrates are mainly used as a stimulant for
milk let-down rather than as supplements to increase intake of crop residues.
Supplementation with molasses/urea
A simple plant for mixing molasses and urea has been constructed, with FAO
assistance, at a sugar factory 20 km south of Moshi municipality and about
45-60 km from villages in the highlands of Hai District. The molasses/urea
mixture is normally transported to storage tanks built at various cooperative
societies which are supply centres to the smallholder farmers. Because of high
transport costs, the cost of using molasses/urea as a supplement to enhance
intake of crop residues is also high, and is likely to increase even more with the
frequent rises in the price of fuel.
388
Opportunity cost of crop residues
There is competition between the utilisation of crop residues as a dairy cattle
feed and their utilisation to maintain soil fertility in the lowland zone. Most of
the crop residues are taken away from farms in the lowland zone and fed to dairy
cattle in the highland zone. The cow dung is never recycled back to the farms in
the lowland zone; instead it is used for coffee/banana production in the highland
zone. Therefore farmers in the lowland zone have to use commercial fertilisers to
maintain soil fertility in their farms.
The opportunity cost of using crop residues as feed for dairy cows is the
value foregone by not using them to maintain soil fertility.
COSTS ASSOCIATED WITH PLANTED PASTURES
Explicit costs associated with planted pasture are seed, labour and fertiliser or
manure costs.
Seed costs
Most smallholder farmers in the highland zone have Guatemala grass, setaria
and elephant grass near their homesteads and so can obtain planting materials for
these grasses from their own plots or from neighbours at no cost. Forage legumes
are not widespread but Desmodium cuttings are available free of charge in most
villages in the highlands. Desmodium seeds are, however, difficult to obtain. The
Dairy Feeding Systems project has established seed production plots at two sites
in Hai District but the Desmodium seed output from these plots is not yet enough
to satisfy demand. The small amount of seed that is produced is currently
distributed to small farmers free of charge, but it might be necessary in future to
charge a small fee in order to sustain the seed production and distribution.
Labour costs
Labour for cultivation, planting, weeding, fertilisation, irrigation and cutting and
carrying harvested pasture to cattle sheds is normally provided from within the
family, but hired labour is also used to supplement family labour. Labour charges
for pasture production depend on the type of work performed, and are higher for
cultivation and weeding operations. In general, however, hired labour is
available at relatively low cost.
Fertiliser/manure costs
Manure produced by dairy cows and other types of livestock is widely used in
the highland zone, not only for pasture production but also for coffee/banana
389
production. Use of commercial fertilisers is recommended where soil nutrient
deficiencies cannot be corrected by manure application (Msumali, 1990).
Smallholder farmers obtain manure from their own farms or from neighbours,
mainly free of charge.
The costs involved in using manure for pasture production are the costs of
collecting manure from cattle sheds, carrying it to pasture plots and spreading it
on the plots. If family labour is used the farmer does not incur any explicit costs
for these operations; explicit costs are incurred only if the farmer hires labour.
Opportunity cost of pasture land
Because land is a very scarce resource in the highlands of Hai District, planted
pastures compete for land with coffee and banana production. The opportunity
cost involved in using the scarce land for pasture production rather than
producing coffee/bananas is therefore the value of the coffee and bananas given
up by using the land for establishing pasture.
QUANTITATIVE ANALYSIS OF COSTS ASSOCIATED WITH THE
FEED RESOURCES
Multiperiod linear programming results from a study conducted by Mdoe (1985)
illustrate the impact of changes in transport costs and prices of concentrate
supplements on the profitability of using crop residues and planted pastures as
major feed resources.
Mdoe (1985) developed two 20-year period linear programming models—
one representing a crop-residue feed-management system and the other a pasture
feed-management system—to compare the profitability of using these resources
as major feeds for dairy cattle in the Kilimanjaro highlands. The general
mathematical form of the model is:
p »
Maximise Z-J J Cjk (1 + r)~' Xjk
Subject to:
p m n
and
Xik * 0, Xzk * 0, . . . Xjk * 0
390
where:
Z = present value of the net returns
n = number of activities in the kth period of the model
t = time in years
p = number of periods in the model
r = discount rate
m = number of resources used
b = level of resource constraints
Cjk = revenue or cost per unit of the jth activity in the kth period
(1+r)-1 = present value discount factor at r discount rate for year t
The basic model for each feed management system represented a farmer
keeping crossbred cows. Improved or exotic breeds were modelled by altering
productivity coefficients in the basic models.
The profits determined in each model were defined as the cumulative net
present value (NPV) of net returns over a 20-year planning horizon. The results
of the basic models indicate that the use of planted pastures was more profitable
than the use of crop residues as major feeds for dairy cows (Table 1). When
transport costs were increased by 40% above the 1984 average prices, NPV fell
by 12.3% in the crop-residue system but by only 4.7% in the pasture system
(Table 1).
The extent to which NPV for each system was affected by increases in
prices of concentrate feeds was also assessed. When the price of concentrate feed
was increased by 30% above the 1984 average prices, NPV declined by 5% for
the pasture system and by 28% for the crop-residue system.
Table 1. Netpresent value forpasture and crop residue systems with and without increase in
transport costs
Net present value (TSh)
Pasture system Crop system
Without increase in transport cost 76 655 74 704
With 40% increase in transport cost 73 075 65 527
Source: Mdoe (1985)
CONCLUSIONS
The costs associated with the use of crop residues are higher than those
associated with the use of planted pastures as major dairy feeds in the highlands
of Hai District. They are also affected more by increasing transport costs and
prices of concentrate supplements, because crop residues must be transported
from the lowland zone to the highland zone whereas pastures are established
near the homesteads, and because crop residues require relatively large amounts
391
of concentrate supplements to improve their nutritive value as compared to
planted pastures. In the short term, initial pasture establishment costs may make
pasture production more costly than the utilisation of crop residues. In the long
term, however, utilisation of planted pastures becomes less costly than utilisation
of crop residues, especially with the ever-increasing fuel prices. Smallholder
farmers with limited land to establish adequate pastures should feed crop
residues supplemented with forage legumes to increase their returns through
higher intake and more efficient digestion.
REFERENCES
Beinerlein J G. 1986. Principles ofagribusiness management. Reston Prentice-Hall,
Englewood, New Jersey, USA.
Kategile J A, Said AN and Sundstol F (eds). 1981. Utilization oflow quality roughages in
Africa. Proceedings of a workshop held at Arusha, Tanzania, 18-22 January 1981.
AUN Agricultural Development Report 1. AUN (Agricultural University of Norway),
Aas, Norway. 220 pp.
Kiflewahid B, Potts G R and Drysdale R M (eds). 1983. By-product utilization for animal
production. Proceedings of a workshop held at Nairobi, 26-30 September 1982.
IDRC-206e. IDRC (International Development Research Centre), Ottawa, Canada.
Mdoe N Y S. 1985. An economic analysis ofalternative dairyfeed management systems
in the highlands ofKilimanjaro, Tanzania. MSc Thesis. University of Guelph,
Ontario, Canada.
Mdoe N S Y and Mlay G 1. 1990. The Kilimanjaro dairy feeding systems: An attempt at
evaluating the impact of on-farm livestock research. In: Dzowela B H, Said AN, Asrat
Wendem-Agenehu and Kategile J A(eds), Utilization of research results on forage
and agricultural by-product materials as animalfeed resources in Africa. Proceedings
of the first joint workshop held in Lilongwe, Malawi, 5-9 December 1988.
PANESA/ARNAB (Pasture Network for Eastern and Southern Africa/African
Research Network for Agricultural By-products). ILCA (International Livestock
Centre for Africa), Addis Ababa, Ethiopia, pp. 208-221.
Msumali G P. 1990. Interpretation of soil analysis results: Soil samples from the SUA/
IDRC Dairy Feeding Systems Project in Hai district. In: Project progress report for
the periodJan to June 1990. SUA/IDRC (Sokoine University of Agriculture/
International Development Research Centre) Project File 3-P-87-0023. Sokoine
University of Agriculture, Morogoro, Tanzania.
Osburn D D and Kenneth C S. 1982. Modern agricultural management. Reston
Publishing Company, Virginia, USA.
Wanapat M and Devendra C (eds). 1985. Relevance of crop residues as animalfeeds in
developing countries. Proceedings of an international workshop held at Khon Koen,
Thailand, 29 November-2 December 1984. Funny Press, Bangkok, Thailand.
392
MANAGEMENT OF THE WESTAFRICAN DWARF GOAT IN
THE HUMID TROPICS: A SOCIO-ECONOMIC APPRAISALOF
FEEDING REGIMES
Olufemi Oludimu
Department of Agricultural Economics
Obafemi Awolowo University
Ile-Ife, Nigeria
ABSTRACT
A management package for dwarf goat production developed on-station at
Ile-Ife, Nigeria, is now being tested on-farm at the village level. Among other
issues, the project is investigating the zootechnical and socio-economic
implications of changing from a traditional feeding regime based on roadside
grass and household kitchen byproducts (cassava, yam and banana peelings,
maize bran) to a diet of good quality browse (Gliricidia sepium and Leucaena
leucocephala) and grass (Panicum maximum). While highlighting the favourable
effects of a browse-based diet on animal performance, this paper draws attention
to some socio-economic implications of adopting such a feeding regime. It is
argued that factors to consider include the prevailing farming systems in each
locality and the investments required, in terms of land and labour, for goat
production in relation to competing enterprises.
RESUME
Gestion de la chèvre naine d'Afrique occidentale en region tropicale humide:
evaluation socio-economique des regimes alimenlaires
Un paquet technolgique élabore en station a lie Ife sur la gestion de la chèvre
naine d'Afrique occidentale est actuellement en cours d'experimentation en
milieu reel. Entre autres questions, les travaux effectues etudient les
consequences zootechniques et socio- economiques du passage du mode
d'alimentation traditionnel base sur la divagation et les ordures menagères
(pelures de manioc et d'igname, son de mats) a un regime alimentaire consume
defourrages ligneux de qualité (Gliricidia sepium et Leucaena leucocephala) et
de graminees (Panicum maximum). Apres avoir souligne les avantages d'un
régime a base de ligneux quant aux performances des animaux, cette etude
393
souligne certaines des consequences socio-economiques de I' adoption d'un tel
système. II est propose, avant d'introduire un tel systeme, non seulement
d'examiner depres un certain nombre de parametres, y compris le type de
système en place, mats egalement de comparer les investissements en terre et en
main-d'oeuvre necessaires pour I'élevage caprin aux autres exigences
eventuelles d'autres activites coneurrentielies.
INTRODUCTION
Goats are an important and preferred source of meat in the humid tropics and
particularly in southern Nigeria. To individual owners, goat rearing is also an
important source of income. In a 1977 study of two villages in the humid tropical
zone of southern Nigeria, Matthewman (1977) indicated that 91% of farmers
interviewed gave cash income as the main reason for keeping animals. Okali and
Sumberg (1985) also indicated that small ruminants are one of a limited number
of sources of income large enough to be used for capital investment.
Given the importance of the goat to the socio-economic milieu of the rural
population, a study of goat production management and feeding patterns in the
humid tropics deserves attention. This paper examines some socio-economic
considerations with respect to feed provision to West African Dwarf goats
maintained under the extensive (traditional) and intensive (modern) management
systems. The paper draws largely on the experience gathered from the West
African Dwarf Goat (WADG) Research Project at Ile-Ife, Nigeria.
BACKGROUND INFORMATION ON THE WADG PROJECT
The joint Nigerian/Dutch research project "Management of the West African
Dwarf Goat in the Humid Tropics" began in August 1981 with on-station
research at Obafemi Awolowo University, Nigeria. Adopting an interdisciplinary
approach (animal science, plant science, agricultural economics and extension),
the project came up with a management package for dwarf goat production. The
package has elements in common with alley farming developed by the
International Institute for Tropical Agriculture (IITA) and with the goat
improvement programme of the International Livestock Centre for Africa
(ILCA), but differs from both by incorporating health and disease control with
nutrition and management of the goats. The elements of the Ile-Ife package are:
Health: Animal vaccination against Peste de Petits Ruminants and quarterly
dipping or washing with lindane solution against ectoparasites (mites, lice).
Nutrition: Based on roadside grass (Panicum maximum), browse products
(Gliricidia sepium and Leucaena leucocephald) and industrial byproducts
(brewers' dried grains) for critical periods.
Management: Housing in bamboo huts with slatted floors. Twice daily
feeding of adults and growers on a group basis, with suckling kids supplemented
394
in a creep feed area. Semi-controlled breeding, with bucks being rotated daily
between pens with breedable females.
At present, the components of this package are being tested on-farm (Moll,
1989). The on-farm programme focuses on three broad topics:
• the actual performance of the various goat-keeping subsystems under
village conditions
the possibilities various types of households have for the potential
incorporation of any of the goat-keeping subsystems
• the actual acceptance of the various goat-keeping subsystems in the villages
One subsystem relates to goat feeding regimes (nutrition subsystem) which
is the issue that is of particular interest to the present paper. In the next section,
two feeding regimes are identified and their essential characteristics discussed.
FEEDING REGIMES
Traditionally, goats in south-west Nigeria are free-roaming in an extensive
management system. In this system, forage crops are not grown to support the
animals and the animals' manure is not returned for cultivation of food crop
plots. Thus, the animals appear to be poorly integrated in the prevailing farming
system. Moll (1989) laments the non-use of manure from goats and argues that if
manure from goats is used properly, it can complement the production of
valuable crops like vegetables and fruits.
Under the extensive management system, goats scavenge all day to feed
themselves; at best, they are offered feed supplements such as kitchen refuse,
dried cassava, cassava/yam/banana peelings, bean husks and maize chaff. The
only major investment is in acquiring new stock, and returns from this system
are low.
Drawing on a study undertaken by ILCA in 1983 (Mack, 1983) and on-
station data obtained from the Obafemi Awolowo University, Huijsman (1987)
remarks that there is a substantial increase in reproductive performance of dwarf
goats when the animals are kept under the high intensity model. The productivity
(liveweight production per doe) more than doubles from 10.9 kg liveweight/doe
per year in the low intensity (extensive) model to 24.2 kg in the high intensity
(intensive) model.
Huijsman (1987) indicates that "this increase is due to a higher average
litter size at birth, higher survival rates of weaners and growers and a substantial
increase in liveweight of growers at 12 months" (see Table 1).
The other feeding regimes that have been advocated, therefore, are the
intensive types which include the cut-and-carry method. In this procedure,
leguminous trees planted in alley farms or intensive feed gardens provide a high-
protein diet to small ruminants. Devised by IITA, alley farming involves growing
arable crops in alleys between cultivated hedgerows of leguminous shrubs such
as Leucaena leucocephala or GliricUUa sepiwn in a system that allows hedgerow
foliage to be removed and fed to livestock without adverse effects on crop yields.
395
1.50 1.74
259 267
2.1 2.4
67 75
77 95
1.09 1.69
10.0 14.3
10.9 24.3
Table 1. Reproductive performance data ofdwarfgoats in humid south-west Nigeria
Performance indices Low intensity model High intensity model
Average litter size (kids/litter)
Parturition interval (days)
Annual reproductive rate (kids/doe
per year)
Survival rate to weaning (%)
Survival rate 3-12 months (%)
Effective kidding rate (kids surviving
to 12 months)
Liveweight at 12 months (kg)
Productivity (liveweight production
per doe per year) (kg)
Source: Huijsman (1987)
The grazed fallow system, on the other hand, was conceived by ILCAand
consists of a rotation of blocks of alleys with three to five years of alley cropping
followed by two to three years of grazing, representing a high degree of
integration of crop and livestock production. Both of these devices demand
considerable management skills to ensure success.
At Ile-Ife, a modified form (probably requiring less managerial capabilities)
involves the establishment of intensive feed gardens consisting solely of a
mixture oiLeucaena leucocephala and Gliricidia sepium close to the homestead.
Planting close to the homestead reduces the time needed to carry the browse to
the animals, but requires considerable labour, not only to tend the gardens but
also to ensure that adequate quantities of browse are continually supplied
(physically carried) to the goats in confinement. Given this requirement, the
system has to be viewed within the context of the resource base and resource
utilisation in particular farming systems.
GOAT-KEEPING IN THE IFE/EDE FARMING SYSTEMS
FRAMEWORK
A farming systems approach should be followed when appraising the
acceptability potentials of an intensive goat feeding regime. The approach should
centre on the role of animal husbandry with regard to the availability and use of
resources, while paying special attention to those components of the farming
system that are either competing with or complementary to rearing the animals.
This section examines the availability and utilisation of land and labour required
for goat-keeping in the Ife/Ede zone of south-west Nigeria.
The case study is the group of six WADG on-farm research villages, three
each in Ife South and Ede Local Government Areas. In five of the villages (Awo,
396
Ikotun and Ojo in Ede and Toro and Akeredolu in Ife South), goats are allowed
to roam freely. In a sixth (newly selected) village, Ogbagba in Ife South, the
movement of goats is restricted under a local regulation because of the damage
done to standing crops and other agricultural products. Farmers who have to
confine their goats now contend with the issues of land and labour availability
and use.
Availability and use of land
At present, availability of land does not seem to be a constraint to farming.
During interviews conducted in 1989, farmers in all villages except Toro and Ojo
said they had surplus land (see Alofe et al, 1989). In fact, at Akeredolu, the
government was able to acquire vast areas of land to start a big project, the
school-leavers farming scheme under the National Directorate of Employment.
But although land is generally available, its acquisition, especially in the Ede
area, still follows the traditional rules whereby land transactions require approval
from the village chief.
In terms of use, the traditional shifting cultivation practice, involving
essentially the growing of food crops, is gradually being replaced by a more
permanent system of cultivation involving kola, cocoa and oil palm trees. Such a
change is being facilitated with the adoption of the government-sponsored
Structural Adjustment Programme (since 1986) with its export crop orientations.
With the development of favourable prices for export crop products, the
tendency is for farmers to devote more cultivable land to cocoa and other export
crops, with feed gardens being a poor competitor.
The location of a feed garden also matters. Usually, it is advantageous that
the feed garden be located as close as possible to the goat paddock near the
homestead. Field investigations reveal that plots close to the homestead are
planted to food crops by farmers whose ability to travel far into the fields is now
limited due to old age. Thus feed gardens may have to compete with food crops.
Availability and use of labour
Availability of labour is diminishing in the villages as able-bodied youths leave
to seek city employment and are only partly replaced by migrant labourers and
settlers from the Middle-Belt. To produce food for family living, village women
now spend more and more time on the farm in addition to their traditional tasks
of processing and trading in food products. The question then arises: Can the
women who traditionally keep goats under the extensive system still cope with
the higher labour requirements of an intensive goat-keeping system?
In the study areas, hired labour is used at peak periods of land preparation,
weeding and harvesting. Furthermore, exchange labour (farmers assisting each
other in turn) is used in particular places. Hired/exchange labour is used
397
extensively on food crop and export crop farm operations especially during the
months of April to July.
Respondents mentioned that during the slack months they engage in other
occupations; for men these include palm-wine tapping, bricklaying and
blacksmithing, and for women, processing of oil palm, rice and beans into
various products. For all villages, except Akeredolu, many families also have
members working off the farm, outside their villages. Thus, feeding the goats
from feed gardens has to compete for labour with food crop production in peak
periods and with secondary occupations all the year round.
CONCLUSIONS
Under conditions of scarce family labour resources, the incremental return to an
additional labour investment provides an important indicator of the economic
attractiveness of such an investment. The incremental returns per labour hour for
moving from the extensive feeding regime must be higher than the average wage
rate prevailing in the locality. Alternatively, intermediate regimes of feeding the
goats must be found which involve minimal land and labour investments.
REFERENCES
Alofe C O, Oludimu O L, Oyeyemi D O and Platteuw W L. 1989. An exploratory survey
ofsix villages in Ede and Oranmiyan Central. Technical Report No 3. West African
Dwarf Goat Research Project, Department of Animal Science, Obafemi Awolowo
University, Ile-Ife, Nigeria.
Huijsman A. 1987. Prospects of intensive goat rearing in the humid zone ofNigeria.
WADG [West African Dwarf Goat] Project Report. Royal Tropical Institute,
Amsterdam, The Netherlands.
Mack S D. 1983. Evaluation of the productivities of West African DwarfGoats and Sheep.
Humid Zone Programme Document No 7. ILCA (International Livestock Centre for
Africa), Addis Ababa, Ethiopia.
Matthewman R W. 1977. .A survey ofsmall livestockproduction at the village level in the
derived savanna and lowlandforest zones of south-west Nigeria. Study No 24,
Department of Agriculture and Horticulture, University of Reading, Reading, UK.
Moll H AJ. 1989. On farm research programme of the West African DwarfGoat Project:
Socio-economic activities, November 1989. Discussion Paper on the West African
Dwarf Goat Project, Department of Animal Science, Obafemi Awolowo University,
Ile-Ife, Nigeria.
Okali C and Sumberg J E. 1985. Sheep and goats, men and women: Household relations
and small ruminant development in south-west Nigeria. Agricultural Systems
18:39-59.
398
RESEARCH PRIORITIES FOR THE DEVELOPMENT OF
APPROPRIATE FEEDING SYSTEMS FOR DAffiY
PRODUCTION IN SUB-SAHARAN AFRICA
EA Olaloku andS Debre
International Livestock Centre for Africa (ILCA)
BP 60, Bamako, Mali
ABSTRACT
Inadequate feed supplies remain a major constraint to sustainable cattle
production in general, and milk production in particular, in smallholder
production systems throughout sub-Saharan Africa. In the emerging peri-urban
dairy production systems in West and central Africa, for example, poor
development of feed resources has invariably resulted in milk production being
sustained at comparatively high feed costs, thus reducing the competitiveness of
locally produced milk.
Given the opportunities for generating increased quantities of crop residues
from many of the crop production projects assisted by international agencies (eg,
World Bank, Global 2000), there is an urgent need to identify research priorities
in the development of feeding systems appropriate to the different smallholder
production systems. Such feeding systems will have to incorporate a new
approach to cattle management, involving cultivation of specialised fodder crops
and harvesting and conservation of crop residues for milk production.
RESUME
Priorités en matiere de recherche sur I Elaboration de systemes a"alimentation
adaptes a la production laitière enAfiique subsaharienne
L'insuffisance des ressources alimentaires demeure un obstacle majeur au
aeveloppement de la production bovine en général et laitiere en particulier dans
les systèmes du petit élevage en Afrique subsaharienne. Dans les systemes
peri-urbains de production laitiere apparus récemment en Afrique occidentale et
centralepar exemple, les penuries alimentaires rencherissent invariablement le
cout des aliments du betail, diminuant ainsi la competitivité du sous-secteur de
la production laitiere locale. Etant donne qu'un bon nombre deprojets de
production végetale soutenuspar des institutions Internationales (ex.: Banque
399
mondiale, Global 2000, etc.) peuventpermettre a I'heure actuelle d'accroitre la
production de résidus de récolte, il importe de definir sans délai lespriorites de
recherche en ce qui conceme I' elaboration de methodes d alimentation adaptees
aux differents systèmes de la petite exploitation laitiere. Cela suppose une
approche nouvelle duproblème de la gestion du cheptel bovin, la culture de
plantesfourrageres appropriées ainsi que la collecte et la conservation de
residus de récolte en vue de la production laitiere.
INTRODUCTION
Dairy supplies in most countries of sub-Saharan Africa are based on both
domestic production and imports, since domestic production has always been
inadequate in relation to demand (von Massow, 1989; Senait Seyoum, 1988).
Given the large ruminant population of sub-Saharan Africa and the fact that
the region covers an estimated 129 million hectares of arable land and 70.24%
(556.9 million hectares) of Africa's permanent pastures (Table 1), there should
be no cause for deficits in milk supplies. However, the estimated 164.2 million
cattle, 147.8 million goats and 127.2 million sheep in the region produced only
an estimated 11.98 million tons milk, providing an average 25.1 kg milk/person
per year for the region's 477.7 million people (FAO, 1989).
Table 1. Human and livestockpopulations, land-use patterns and milkproduction in sub-Saharan
Africa
Population (thousands)
In sub-Saharan Africa % of total Africa
Humans 477 661 75.99
Cattle 164169 88.36
Sheep 127 241 63.39
Goats 147 757 87.18
Land area (thousands of hectares)
Total 2034141 68.63
Arable land 129054 76.84
Permanent crops 14140 75.55
Permanent pastures 556 963 70.24
Milk production (thousands of tonnes)
Cow milk 9079 65.85
Goat milk 1718 83.76
Sheep milk 1188 78.62
Source: FAO (1989)
400
The economic depression in many sub-Saharan African countries, brought
about by the external debt burden, has severely curtailed the availability of
foreign exchange to sustain dairy imports. The overall effect has been a
worsening of the dairy supply situation at a time when the need for more food to
feed the region's ever-growing population has become very acute. Indeed, the
inadequacy of dairy supplies has been aggravated by a combination of drought
and other adverse climatic factors and an unstable political situation in some
countries. When viewed against the possible outcome of the on-going "Uruguay
Round of Talks" on world trade and the rationalisation of agricultural subsidies
in Europe and North America, the prospects for cheap dairy imports to
supplement domestic production in sub-Saharan Africa look increasingly gloomy.
These developments present challenging opportunities for increasing
domestic dairy production through a more efficient use of the resources in the
existing production systems. Research support from the commodity and strategic
collaborative research networks would be required to generate producer-
implementable technology packages for sustainable increases in domestic dairy
production throughout the region.
EXISTING PRODUCTION SYSTEMS
Domestic dairy production in sub-Saharan African countries is based largely on
cattle. In 1989, for example, cattle milk accounted for 75.8% of the estimated
11.98 million tons of milk produced in the region (Table 1).
Dairy production is carried out under a variety of production systems which
can be classified into two broad groups, traditional systems and improved
systems, the major characteristics of which have been summarised by Olaloku et
al (1990).
The traditional systems include the pastoralist, subsistence and
agropastoralist systems, all of which together account for well over 90% of the
dairy ruminant population in sub-Saharan Africa. Dairy production from each
system reflects varying degrees of adaptation to the major constraints to
sustainable production in their environment, such as seasonal variations in feed
and water resources, animal health and social interactions within the overall
farming system (ILCA, 1979; Synge, 1981; Jahnke, 1982; Waters-Bayer, 1988).
Jahnke (1982) described production in mixed farming areas with the tradition of
communal tenure of the grazing resources. Where cropping is the mainstay of
subsistence and income, stubbles become important as a grazing resource.
Dairy production under the improved systems represents adaptations of the
intensive, high input/output market-oriented production systems of the
developed dairy industries in Europe and North America. The improved
production systems include:
• intensive crop-livestock smallholder systems
• semi-intensive medium and large scale systems
• peri-urban dairying.
401
In general, production is low under the traditional systems and much higher
under the improved systems. These differences in productivity have generally
been ascribed to:
• use of improved genotypes (crossbreds, grade and pure bred exotic dairy
breeds)
• investments in forage and other feed resources to ensure adequate nutrition
year-round
• animal health care, with conscious efforts to reduce reproductive wastage,
calf mortality and morbidity.
FEED RESOURCES
Apart from differences in productivity arising from the quality of the animal
genotypes under the different production systems, the most important constraint
to sustainable dairy production in sub-Sahran Africa is feed and nutrition.
The availability of feed, both in quantity and quality, varies greatly in the
different production systems. Although feed availability depends to some extent
on climatic conditions, particularly rainfall and the length of the growing season,
in most cases the feed situation becomes critical during the dry season. At this
time, the low quality of natural pastures and the inefficient use of crop residues
result in inadequate feeding of stock with adverse implications on reproductive
efficiency and milk production, especially among crossbred and grade cattle as
feed nutrients become inadequate to support their potential yield levels.
Feed resource inventory
A wide variety of feed resources abound from sub-Saharan Africa' s estimated
129 million hectares of arable land and 556.9 million hecrares of permanent
pastures. These include:
Crop residues, especially cereal straws and stover from sorghum, maize,
millet, rice, wheat, oats and barley, accruing from arable crop farming both in the
smallholder units and in the large-scale accelerated food production projects
sponsored by various international development agencies in recent years. These
products are usable to various degrees to support production, depending on the
crop variety, tannin content, stage of harvest, length of storage, leafstem ratio,
soil fertility and fertiliser application, as well as the effects of agronomic
practices such as irrigation. For example, Kernan et al (1979) reported that straw
from irrigated wheat had a 41% in vitro digestibility compared to 34% for
non-irrigated wheat straw. Most cereal straws are, however, low in nitrogen
content and require considerable strategic utilisation to be effective feeds.
Agro-industrial byproducts, ranging from products with high-nutrient
content such as wheat offals and middlings, brewers' grains, etc, to low nutrient
and fibrous products such as sugarcane bagasse, rice hulls and cocoa husks.
402
Pasture forage and herbaceous legumes, consisting of the more popular
planted grasses such as Napier grass (Pennisetum purpureum), Rhodes grass
(Chloris gayana), legume forages such as Stylosanthes and different varieties of
alfalfa (Medicago sativa). Recently multipurpose trees such as Sesbania and
Leucaena species have been developed as useful sources of nitrogen in the diet.
Utilising feed resources for milk production
Fibrous crop residues can, at best, only support low levels of milk production
because of their low and slow rate of digestibility, low propionate fermentation
in the rumen, and almost negligible content of fermentable nitrogen. However,
these feeds represent a significant proportion of the feed resources available to
the majority of smallholder producers in sub-Saharan Africa. Therefore, greater
attention would have to be given to their improved and more efficient utilisation
for dairy production.
Improvements can be achieved through treatment with ammonia, such as
ensiling with urea. Khan and Davis (1981) and Perdok et al (1982) have
demonstrated the value of ammoniated rice straw, with average increases of 53%
in milk production from zebu and buffalo cows. The increased intake of the
treated straw is brought about a reduction from 14 to 9% in the average
proportion of the total diet represented by concentrates. There will, however, be
a need to establish acceptable regimes for feeding lactating ruminants.
Green forage can be used as a supplement for milk production. Perdok et al
(1982) showed that supplementing a diet of untreated straw with Gliricidia
sepium at approximately 15% of the dietary dry-matter intake increased milk
yield by 22%.
EXAMPLES FROM EXISTING PRODUCTION SITUATIONS
Although there is potential for increasing domestic milk production in
sub-Saharan Africa, poor feed resource development and utilisation could lead to
lower competitiveness of locally produced milk. This is the trend emerging from
the peri-urban dairy production systems operating in some countries of the
region, particularly in the subhumid zones of West and central Africa.
Peri-urban dairy production
The depressed economic situation, coupled with the increasing costs of dairy
imports against the background of inadequate foreign exchange and the
availability of a good market in urban areas, has led to the development of dairy
production in urban and peri-urban areas of many countries in sub-Saharan
Africa. This system of dairy production has assumed increasing importance in
the past decade, as more and more milking herds are established within a 50-km
403
radius of major cities and towns. Indeed, national and international development
agencies now see peri-urban dairy production as an important mechanism for
catalysing organised dairy production and providing employment opportunities.
Factors in favour of intensifying dairy production in urban and peri-urban
areas include the proximity of production sites to centres of high fresh milk
demand, which leads to reductions in costs associated with collection,
refrigeration and transport of fresh milk from production sites to points of final
sale. On the input side, urban and peri-urban producers have ready access to feed
supplements, agro-industrial byproducts, veterinary supplies and, sometimes,
factory-gate prices. However, arguments against peri-urban dairy production
include:
• unavailability or restricted availability of low-cost feed sources such as
natural pastures and crop residues
• inadequate land for forage cultivation
high costs of purchased feed inputs
• high labour costs for herding and feeding.
Feeding for peri-urban dairy production in Mali
Preliminary results of a recent ILCA study on three dairy production systems in
peri-urban Bamako, in the subhumid zone of Mali, showed that purchased feeds
represented between 34 and 73% of the total variable costs of milk production.
In the traditional production system in which purchased feed supplements were
fed exclusively in the dry season, supplements represented the major source of
expenditure. The preliminary economic analysis also showed that the high costs
of purchased feeds resulted in milk production being sustained at comparatively
higher costs than the reconstituted imported dairy products (Table 2).
Prospects for increasing peri-urban dairy production
There is a high demand for fresh milk in and around Bamako, so opportunities
exist for increasing production to meet this demand as well as to generate more
producer income. But these aspirations can only be achieved if cheaper sources
of feed can be developed. The cottonseed-cake-based supplement, containing
about 27% crude protein, costs FCFA80/kg at farm level. Research into the
development of feeding packages for milk production, incorporating forage
legumes, crop residues and agro-industrial byproducts, may identify cheaper
alternative feeds for peri-urban dairy production in the Bamako area.
The research support required for sustainable dairy production in
sub-Saharan Africa would therefore require an analysis of the existing
production systems, followed by the design, evaluation and implementation of
appropriate interventions, to increase productivity and generate additional
income for the producer.
404
Table 2. Production, cost structure andprofits from milk production per cow in three different
production systems in the Bamako area, Mali, July to October 1989
Per cow
Peri-urban
Item Traditional system Communal system Private system
Physical data
Milk production (litres/day) 1.02 2.24 2.28
Concentrate (kg/day) 0.80 1.55 3.00
Milk yield/kg concentrate fed
(litres/day)
1.30 1.44 0.95
Profit (loss) (FCFA)
Revenue from milk 129 476 602
Variable costs
Cost of supplementation 68 124 240
Veterinary costs 8 17 175
Hired labour costs 5 30 300
Total 81 171 715
Profit (loss) 48 305 (113)
This scenario has been amply demonstrated in some of the dairy production
projects supported by the International Development Research Centre (EDRC) in
Botswana, Burundi and Malawi (Olaloku et al, 1990). In each case, the research
priority focused on the development of feeding strategies based on the available
feed resources (cereal crop residues) supplemented with a forage legume, Lablab
purpureus, as the protein source.
In designing research to solve the feed problems of producers, the farming
systems research approach should not be ignored. The first step must be to
characterise existing production systems in order to identify the calving calendar,
calf mortality, milk offtake and reproductive activity in relation to available feed
resources. Such knowledge then becomes useful in the development of
appropriate feeding strategies for increased milk offtake and producer incomes
according to requirements at different seasons of the year.
Given a good knowledge of the foregoing, research can then be designed to
address such issues as:
quantification and nutritional evaluation of available feed resources,
especially the seasonally available forages, to provide information for their
optimal exploitation for increased milk production
development of feeding and management packages for milking cows,
calves and replacement stock, based on existing feed resources, to ensure
reductions in mortality and to achieve good growth rates, early maturity and
calving at an earlier age
405
• development of management systems for range and pasture improvement,
as well as methods for the production and conservation of herbage for
dry-season feeding
• development of simple diets from available feed resources for maximising
production under particular local conditions.
Finally, in the design of research for feed production and utilisation for
sustainable dairy production, provision must be made for the on-farm packages
for year-round milk production levels with existing stock and available feeds and
feed combinations.
REFERENCES
FAO (Food and Agriculture Organization of the United Nations). 1989. FAO production
year book, Volume 43. FAO, Rome, Italy. 346 pp.
ILCA (International Livestock Centre for Africa). 1979. Livestockproduction in the
subhumidzone of WestAfrica. ILCASystems Study 2. ILCA Addis Ababa, Ethiopia.
pp. 19-77.
Jahnke H E. 1982. Livestockproduction systems and livestock development in tropical
Africa. Kieler Wissenchaftsverlag Vauk, Kiel, FR Germany. 253 pp.
Keman J A Crowle W L, Spurr D T and Coxworth E C. 1979. Straw quality of cereal
cultivars before and after treatment with anhydrous ammonia. Canadian Journal of
Animal Science 59:511-517.
Khan AKMN and Davis C H. 1981. Effect of treating paddy straw with ammonia
(generated from urea) on the performance of local and crossbred lactating cows. In:
Jackson M G, Dolbeig F, Davis C H, Haque M and Saadullah M (eds), Maximum
livestockproductionfrom minimum land. Proceedings of a seminar held in
Bangladesh. Bangladesh Agricultural University, Mymensingh, Bangladesh. pp.
168-180.
von Massow V H. 1989. Dairy imports into sub-Saharan Africa: Problems, policies and
prospects. ILCA Research Report 17. ILCA (International Livestock Centre for
Africa), Addis Ababa, Ethiopia. 46 pp.
Olaloku EA Smith O B and Kiflewahid B. 1990. Bio-economical characteristics of
existing dairy production systems in Africa and suggestions for improvement. In:
Proceedings, IDRC symposium, XXIII International Dairy Congress, Montreal,
Canada (in press).
Perdok H B, Thamotharam M, Blom J J, van den Bom H and van Veluw C. 1982.
Practical experiences with urea ensiled-straw in Sri Lanka. In: Preston T R, Davis C,
Dolberg F, Haque M and Saadullah M (eds), Maximum livestockproductionfrom
minimum land. Proceedings of the third seminar held in Bangladesh, 13-18 February
1982. Bangladesh Agricultural University, Mymensingh, Bangladesh. pp. 123-134.
Senait Seyoum. 1988. Patterns of consumption ofdairy products in WestAfrica.
Livestock Economics Division Working Document 11. ILCA (International Livestock
Centre for Africa), Addis Ababa, Ethiopia. 52 pp.
406
Synge B A. 1981. Milk production under extensive systems. In: Huhn J H (ed),
Proceedings of the conference on impact ofanimal disease research and control on
livestockproduction in Africa. German Foundation for International Development,
Feldafing, FR Germany. pp. 18-24.
Waters-Bayer A. 1988. Dairying by settled Fulani agro-pastoralists in central Nigeria.
Kieler Wissenchaftsverlag Vauk, Kiel, FR Germany. 328 pp.
407
408
APPENDIX

LIST OF PARTICIPANTS
Botswana
AAAganga
Botswana Agricultural College
Private Bag 0027
Gaborone
W S Boitumelo
Department of Agricultural Research
Private Bag 0033
Gaborone
LPGakale
Department of Agricultural Research
Private Bag 0033
Gaborone
J Macala
Department of Agricultural Research
Private Bag 0033
Gaborone
W Mahabile
Department of Agricultural Research
Private Bag 0033
Gaborone
H B Makobo
Ministry of Agriculture
Private Bag 003
Gaborone
B Kgamanyane
Ministry of Agriculture
Private Bag 003
Gaborone
R Kwerepe
Ministry of Agriculture
Private Bag 003
Gaborone
M L Kyomo
Southern African Centre for
Cooperation in Agricultural
Research (SACCAR)
PO Box 00108
Gaborone
M G Lebani
Ministry of Agriculture
Private Bag 003
Gaborone
B Masilo
Department of Agricultural Research
Private Bag 0033
Gaborone
N Masunga
Ministry of Agriculture
Private Bag 003
Gaborone
K Mokgotle
Department of Agricultural Research
Private Bag 0033
Gaborone
A B Moyo
Department of Agricultural Research
Private Bag 0033
Gaborone
411
P Mutshewa
Ministry of Agriculture
Private Bag 003
Gaborone
B Sebolai
Department of Agricultural Research
Private Bag 0033
Gaborone
Cameroon
R T Fomunyam
Institute of Animal Research
PO Box 125
Bamenda
J Kouonmenioc
Station de recherches zootechniques de
Nkolbisson
BP 1457
Yaound6
ATNgwa
Institute of Animal Research
PO Box 12
Yagoua
R M Njwe
Department of Animal Science
Institut national de développement
rural (INADER)
University Centre of Dschang
BP222
Dschang
Columbia
RVera
Centro Internacional de Agricultura
Tropical
Apartado 6713
Cali
Coted'Ivoire
N C Bodji
Institut des savanes (IDESSA)
Departement elevage
BP 1152
Bouake
TYo
Institut des savanes (IDESSA)
Departement elevage
BP 1152
Bouake
Ethiopia
Alemu Tadesse
Institute of Agricultural Research
PO Box 2003
Addis Ababa
R Griffiths
International Livestock Centre for
Africa (ILCA)
PO Box 5689
Addis Ababa
J Hanson
International Livestock Centre for
Africa (ILCA)
PO Box 5689
Addis Ababa
H Heering
International Livestock Centre for
Africa (ILCA)
PO Box 5689
Addis Ababa
Lemma Gizachew
Institute of Agricultural Research
PO Box 2003
Addis Ababa
412
M Mohamed-Saleem
International Livestock Centre for
Africa (ILCA)
PO Box 5689
Addis Ababa
Mohammed Y Kurtu
Arsi Rural Development Unit (ARDU)
Animal Research Section
PO Box 388
Assela
France
P de Fabregues
Recherches sur les aliments du betail
en Afrique occidental et centrale
(RABAOC)
Institut d' élevage et de médicine
vétérinaire des pays tropicaux
(ffiMVT)
10 rue Pierre Curie
94704 Maisons-Alfort
AN Said
International Livestock Centre for
Africa (ILCA)
PO Box 5689
Addis Ababa
MSall
International Livestock Centre for
Africa (ILCA)
PO Box 5689
Addis Ababa
J E S Stares
International Livestock Centre for
Africa (ILCA)
PO Box 5689
Addis Ababa
D Thomas
International Livestock Centre for
Africa (ILCA)
PO Box 5689
Addis Ababa
J Walsh
Director General
International Livestock Centre for
Africa (ILCA)
PO Box 5689
Addis Ababa
Germany
R C W Konig
Institute of Animal Production in the
Tropics and Sub-Tropics
University of Hohenheim
D-7000 Stuttgart 70
Ghana
AAddo-Kwafo
Agriculture Research Institute (ART)
PO Box 20
Achimota
KAmaning-Kwarteng
Agricultural Research Station, Legon
University of Ghana
Legon
AKTuah
Department of Animal Science
University of Science and Technology
Kumasi
Italy
Pierre-Luc Pugliese
Food and Agriculture Organization of
the United Nations (FAO)
Via delle Terme di Caracalla
00153 Rome
413
Kenya
AAbate
Department of Animal Production
University of Nairobi
PO Box 29053
Nairobi
B H Dzowela
International Centre for Research in
Agroforestry (ICRAF)
PO Box 30677
Nairobi
PNKamau
Department of Natural Resources
Faculty ofAgriculture
Egerton University
PO Box 536
Njoro
J G Mureithi
Kenya Agricultural Research Institute
(KARI)
PO Box 80147
Mombasa
M N Nderito
Kenya Agicultural Research Institute
(KARI)
National Dryland Farming Research
Station
PO Box 340
Machakos
F Nyaribo
Winrock International Institute for
Agricultural Development
Small Ruminant Collaborative
Research Support Program
(SR-CRSP)
PO Box 252
Maseno
S B Kayongo
Department of Animal Production
Faculty of Veterinary Medicine
University of Nairobi
PO Box 29053
Nairobi
B Kiflewahid
International Development Research
Centre (IDRQ
Regional Office for Eastern and
Southern Africa
PO Box 62084
Nairobi
W Migongo-Bake
International Centre for Research in
Agroforestry (ICRAF)
PO Box 30677
Nairobi
ABOrodho
Kenya Agricultural Research Institute
(KARI)
Western Agricultural Research Station
PO Box 169
Kakamega
K Otieno
Small Ruminant Collaborative
Research Support Program
(SR-CRSP)/Kenya Agricultural
Research Institute (KARI)
PO Box 252
Maseno
T Rutagwenda
Department of Animal Production
Faculty of Veterinary Medicine
University of Nairobi
PO Box 29053
Nairobi
414
Madagascar Mozambique
J J Rasambainarivo
Departement de recherches
zootechniques et vetérinaires
(DRZV)
BP4
Antananarivo 101
Malawi
G Kanyama-Phiri
Bunda College of Agriculture
PO Box 219
Lilongwe
J T K Munthali
Chitedze Agricultural Research Station
PO Box 158
Lilongwe
H D C Msiska
Chitedze Agricultural Research Station
PO Box 158
Lilongwe
Mali
KDiallo
International Livestock Centre for
Africa (ILCA)
BP60
Bamako
M Doumbia
Centre de recherches zootechniques de
Sotuba
BP262
Bamako
E Olaloku
International Livestock Centre for
Africa (ILCA)
BP60
Bamako
O Faftine
Instituto de Producao Animal
PO Box 1410
Maputo
Niger
C Kouame
International Livestock Centre for
Africa (ILCA)
ICRISAT Sahelian Centre
BP 12404
Niamey
Nigeria
AAAgishi
International Livestock Centre for
Africa (ILCA)
PMB2248
Kaduna
KAtta-Krah
Alley Farming Network
International Institute of Tropical
Agriculture
PMB 5320
lbadan
G B Ayoola
University ofAgriculture
PMB 2373
Makurdi
O J Ifut
Department of Animal Science
University of Cross River State
Okuku Campus
PMB 1219
Ogoja
Cross River State
415
I E J Iwuanyanwu
National Agricultural Extension and
Research Liaison Services
Ahmadu Bello University
PMB 1067
Zaria
O S Onifade
National Animal Production Research
Institute
Ahmadu Bello University
PMB 1096
Zaria
C P I Onwuka
College of Animal Science and
Livestock Production
University of Agriculture
PMB 2240
Abeokuta
Ogun State
O Oludimu
Department of Agricultural Economics
Obafemi Awolowo University
De-Ife
E N Sabiiti
International Livestock Centre for
Africa (ILCA)
PMB 5320
Ibadan
Senegal
OB Smith
International Development Research
Centre (IDRQ
Regional Office for West and Central
Africa
BP 11007
CD Annexe
Dakar
Sudan
TAMohammed
Department of Animal Nutrition
Institute of Animal Production
University of Khartoum
PO Box 32
Khartoum North
AEEl-Tayeb
Department of Animal Nutrition
Institute of Animal Production
University of Khartoum
PO Box 32
Khartoum North
Swaziland
B H Ogwang
University of Swaziland
PO Luyengo
S Lebbie
University of Swaziland
PO Luyengo
Tanzania
KBiwi
Department of Livestock Development
Ministry of Agriculture
PO Box 159
Zanzibar
A E Kimambo
Department of Animal Science and
Production
Faculty ofAgriculture
Sokoine University of Agriculture
PO Box 3004
Chuo Kikuu
Morogoro
416
M L Kusekwa
Livestock Production Research
Institute
Ministry of Agriculture
PO Box 202
Mpwapwa
C E Lyimo
Dairy Practical Training Centre
Buhuri
PO Box 1483
Tanga
NSYMdoe
Department of Rural Economy
Sokoine University of Agriculture
PO Box 3007
Morogoro
N J Mukurasi
Uyole Agricultural Centre
PO Box 400
Mbeya
NAUrio
Department of Animal Science and
Production
Faculty ofAgriculture
Sokoine University of Agriculture
PO Box 3004
Chuo Kikuu
Morogoro
Togo
DAtisso
Centre regional d' étude appliquées sur
les trypanosomiases (CREAT)
BP 7518
Lome
ATsomafo
BP 1515
Lome
Uganda
FBBareeba
Department of Animal Science
Faculty of Agriculture and Forestry
Makerere University
PO Box 7062
Kampala
P Lusembo
Namulonge Research Station
PO Box 7084
Kampala
United Kingdom
J Bennison
Livestock Section
Overseas Development National
Resources Institute (ODNRI)
Chatham Maritime
Chatham
Kent ME4 4TB
Uruguay
Hector Hugo Li Pun
Associate Director
Centro Internacional de
Investigaciones Para EC Desarrolo
(CUD)
Plaza Cagancha 1335 (Piso 9)
1100 Montevideo
Zambia
E M Aregheore
Department of Animal Science
School of Agricultural Sciences
University of Zambia
PO Box 32379
Lusaka
417
AM Chimwano
Department of Animal Science
School of Agricultural Sciences
University of Zambia
PO Box 32379
Lusaka
JKulich
SialofA/B
Ministry of Agriculture
Lusaka
Zimbabwe
JAKategile
International Livestock Centre for
Africa (ILCA)
PO Box 3211
Harare
LRNdlovu
Department of Animal Science
University of Zimbabwe
PO Box MP 167
Mount Pleasant
Harare
P Nyatbi
Department of Research and Special
Services
PO Box 8108
Causeway
Harare
H M Sibanda
GTZ/ADA-PPU (German Agency for
Technical Cooperation/Agricultural
Development Authority-Provincial
Planning Unit
PO Box 357
Masvingo
L M Sibanda
Department of Animal Science
University of Zimbabwe
PO Box MP 167
Mount Pleasant
Harare
S Sibanda
Grasslands Research Station
P Bag 3701
Marondera
T Smith
Matopos Research Station
Private Bag K 5137
Bulawayo
418


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 ISBN 91-9053-199-1
Printed al ILCA, Addis Ababa, Ethiopia