OVERCOMING 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 is coordinated by ILCA with
the financial support of the International
Development Research Centre (IDRC), Canada
DECEMBER 1989
AFRICAN RESEARCH NETWORK FOR
AGRICULTURAL BY-PRODUCTS (ARNAB)
ILCA, P.O.BOX 5689, ADDIS ABABA, ETHIOPIA



OVERCOMING 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
Edited by
A.N. Said and B.H. Dzowela
Editorial Sub-Committee
A.A. Adegbola, J. A. Kategile, D.A. Little,
M.A. Naga and S. Sibanda
ARNAB is coordinated by ILCA with
the financial support of the International
Development Research Centre (IDRC), Canada
DECEMBER 1989
AFRICAN RESEARCH NETWORK FOR
AGRICULTURAL BY-PRODUCTS (ARNAB)
ILCA, P.O.BOX 5689 ,ADDIS ABABA, ETHIOPIA
This o 
HLE9-RRJ-CD8D
Correct citation: African Research Network for Agricultural By-products (ARNAB).
1989. Overcoming 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, Addis Ababa, Ethiopia.
PREFACE
The theme of the Fourth Annual Workshop was on "Overcoming constraints to
the efficient utilization of agricultural by-products as animal feed". It was held at
the Institute of Animal Research, Mankon, Bamenda, Republic of Cameroun,
20-27 October 1987. The workshop was sponsored by the International
Development Research Centre (IDRC), Canada, which is the co-funding agency
for the African Research Network for Agricultural By-products (ARNAB). The
logistical support was provided by the International Livestock Centre for Africa
(ILCA). The Steering Committee would like to record their appreciation to
IDRC and to ILCA for the financial and logistical support.
His Excellency Mr Abdoulaye Babale, Minister for Higher Education and
Scientific Research of the Republic of Cameroun, was the Guest of Honour and
opened the workshop. Dr Emmanuel D. Tebong, Director of the Institute of
Animal Research, Cameroun, also officiated at the opening ceremony.
The ARNAB Steering Committee would like to record their appreciation to
His Excellency Mr Abdoulaye Babale for finding time in his busy schedule to open
the workshop and for his encouraging words and for his hospitality in hosting the
workshop dinner. The Steering Committee would also like to express their
appreciation to the workshop hosts, the Institute of Animal Research, Mankon,
Bamenda. In particular we would like to express our gratitude to Dr Emmanuei
D. Tebong, the Director and to Dr Ruby Fomunyam, Mankon Station
Manageress, and to all the staff at the station who spent so much of their valuable
time assisting the Secretariat in the various aspects of the workshop organization
and also in playing host to the workshop participants.
Finally we would like to record our thanks and appreciation to the individual
members of the Editorial Sub-Committee for the initial editing of those papers
allocated to them. We would also like to thank Aster Amde, Azeb Bekele, Fantu
Solomon and Tsedale Layeh for word processing some of the papers. We thank
Shewangezew Lemma for putting in so many hours word-processing and formatting
the final camera-ready copies.
Editors.
m
CONTENTS
Page
Strategies for feeding straw to small ruminants: Upgrading 1
or generous feeding to allow selective feeding
E. Owen, R.A. Wahed, R. Alimon and W. El-Naiem
Smallholder livestock production: Constraints on the 22
adoption of improved technologies
E.N. Tambi
Considerations in the design of on-farm livestock 36
experiments and evaluation of results
G.I. Mlay and N.A. Urio
The economics of peasant cattle feeding in Mali 49
H. Baur, K. Sissoko and S. Debrah
Combinations of agro- industrial by-products for use in 61
dairy diets formulated by on-farm use of least cost
ration system
J.M. Chesworth, D.F. McKillop and D.J. Spriggs
Overcoming the constraints of nitrogen availability to 80
improve crop residue utilisation by ruminants in
Burkina Faso
Kassu Yi I a I a
Strategies to overcome constraints in efficient utilization 105
of agricultural by-products as animal feed
L.P. Nkhonjera
Towards efficient utilization of poultry waste by 114
ruminants
E.K. Odhuba
Tephrosia spp and cottonseed (Gossypium spp) cake 133
supplementation of rice and maize stalks fed to sheep
and goats in the dry season
R.T. Fomunyam and S.E. Mbomi
The potential of crop residues, particularly wheat 142
straw, as livestock feed in Ethiopia
Lulseged Gebrehiwot and Jamal Mohammed
Dolichos Lablab (Lablab purpureus) in by-product-based 155
diets for lactating cows in Botswana
Berhane Kiflewahid and B. Mosimanyana
Cereal straws in the feeding system of ruminants in 173
Senegal
S. Fall, H. Guerin, C. SaIl and ND. Mbaye
Overcoming some constraints in feeding crop by-products for 190
mi Ik production
K.M. Biwi
The feeding value of some agro- industrial by-products for 204
beef cattle at Bambui centre
T. Beramgoto
Maize stover as a feed for ruminants 218
T. Smith, C. Chakanyuka, S. Sibanda and B. Manyuchi
Constraints to cereal crop residue utilization in central 232
Tanzania
M.A. Kabatange and A.J. Kitalyi
Grain yield and nutritive value of crop residues from three 239
varieties of maize (Zea mays L) crop
J.E. Fleischer, A.R. Barnes, B. Awumbila, K. Amaning-
Kwarteng and C.K. Tieku
Studies on the utilization of brewers dry grains and wheat 256
offals by calves
F.I. Ogundola
The effect of maize bran on voluntary intake and 267
digestibility of pigeon pea (Cajanus cajan) pods by
goats
J. A. Ayoade
The optimum level of roughages in the diets of sheep 272
A.M. Nour, A.R. Abou Akkada, A. A. Nour and Awad
Mabrouka
Response of the West African Dwarf sheep to diets based on 282
processed cassava peels and G I i r i c i d i a sepium
A. A. Adegbola, O.B. Smith and V.O. Asaolu
Utilization of G I i r i c i d i a sepium and cassava peels by 290
West African Dwarf (WAD) goats in Nigeria
0. J. Ifut
Evaluation of cassava flour and groundnut cake as 306
concentrate supplements for West African Dwarf goats
R.M. Njwe and F.O. Olubajo
Comparison of feed utilization by West African Dwarf sheep 324
fed sodium hydroxide treated soyabean pods
supplemented with soyabean flour or fresh napier
grass fed alone or with soyabean flour
R.M. Njwe and Godwe
Processed and unprocessed sorghum stover in beef 334
finishing rations
T.A. Mohammed, A.E. El-Tayeb, A.F. Mustafa and H.M.
Khogal i
Hydration as a means of improving utilization of maize 343
stover fed to steers
L. R. Ndlovu and Z. Manyame
Improving the intake and utilization of by-product- 354
based diets
M.A. El-Naga
The degradation of untreated and treated maize cobs and 363
cocoa pod husks in the rumen
A.K. Tuah and E.R. Orskov
Potential of agricultural by-products as sources of 379
mineral nutrients in ruminant diets
E. Kabaija and D.A. Little
The preservation of banana crop residues through 394
ensi I ing process
N.H. Sheikh
Solutions to the practical problems of feeding cocoa- 401
pods to ruminants
O.B. Smith
Cocoa-pod silage and cocoa-pod grass silage in goat 418
and sheep nutrition
F.O. Olubajo, M.M. Asonibare and E.O. Awolumate
The evaluation of brewers dried grains (BDG) in poultry 434
rations. 1. Breeder chicken rations
R. Fombad and J. Mafeni
Effects of incorporating rubber seed meal supplemented with 447
blood meal in broiler rations under traditional
condi t ions
Nouke and H.N. Endeley
The effect of water lettuce ( P i s t i a stratiotes L) as a 460
substitute for wheat middlings in broiler finishing
rations
Y. Manjeli, J. Tchoumboue and J. Djoukam
The use of organic manure in aquaculture. 461
I. Polyculture of tilapia (Oreochromis ni lot icus)
and African catfish (Claries lazera) in earthen ponds
receiving chicken manure without supplemental feeding
D. Nguenga
Goat keeping 462
E. Tendo
Recommendations of the Fourth Annual ARNAB Workshop 465
List of participants 468
STRATEGIES FOR FEEDING STRAW TO SMALL RUMINANTS:
UPGRADING OR GENEROUS FEEDING TO ALLOW SELECTIVE FEEDING
1 2 3
E. Owen, R.A. Wahed , R. Alimon and W. El-Naiem
Department of Agriculture, University of Reading,
Earley Gate, P.O.Box 236, Reading RG6 2AT, UK
ABSTRACT
Population growth will accelerate crop - animal integration,
creating a need for stall-feeding systems for goats and sheep
based on crop residues, especially on small farms. Five
experiments with goats and two with sheep showed that allowing
small ruminants to 'stal I -graze' long barley straw will
increase intake because of selective feeding. Allowing goats
to reject 50% of the straw offered, instead of the conventional
ad I ibi tum refusal-rate of 10 to 20%, increased straw dry-
matter intake by 30 to 47%, and that of the estimated
digestible straw by 41 to 78%. In one experiment, goats fed
rejected straw (50% rate) after treatment with ammonia,
consumed as much digestible straw as when the original straw
was fed generously. Botanical fractionation of offered straw
and rejected straw showed goats to select leaf rather than stem
when the amount offered was large enough to allow selective
feeding. Similar experiments with tropical straws are
requi red.
INTRODUCTION
The case for crop residues, small ruminants and stall-feeding
The future importance of agricultural by-products as feeds for
livestock, particularly fibrous by-products for ruminants, is
acknowledged (Owen, 1985). Identifying ways of overcoming
Permanent address:Uni versi ty of Mosul, Mosul, Iraq.
2
Permanent address:Uni versi ty of Pertanian Malaysia, Serdang,
Selangor, Malaysia.
Permanent address:Gezi ra Board, Barakat, Sudan.
constraints to their greater utilisation as feed is therefore
an appropriate theme for the present workshop.
Sundstol and Owen (1984) pointed to the inevitability of
straw being produced as a by-product of growing cereals for
man. With world population predicted to double by 2025, cereal
production and hence straw production, will obviously increase.
This will be particularly so in the developing tropics where
population is likely to treble by 2025. The change will reduce
the area available for pastoral farming and accelerate the
integration of crop and animal (mainly ruminant) agriculture
(Gartner, 1984).
During the past decade the importance of small ruminants
(especially goats) to the agriculture of developing countries
has at last been recognised (Devendra and Burns, 1983; World
Bank and Winrock International, 1983; Timon and Hanrahan,
1986). Less publicised is the fact that the small ruminants
are mainly associated with small farmers; and it is the small
farmers who will increasingly need to practise crop - animal
integration. A major constraint to the latter is damage to
food crops caused by indiscriminate grazing, especially by
goats. For these reasons, we believe that there is need to
research and develop stall-feeding systems for small ruminants
based on crop by-products.
Background to experiments undertaken - the grazing animal
Methods of upgrading straws as feed are well documented
(Sundstol and Owen, 1984) and guidelines on researching the
subject are published (Preston et al, 1985). There has been
more emphasis on upgrading straws for cattle than sheep
(Greenhalgh, 1984) but goats have received little attention
(Owen, 1981; Owen and Kategile, 1984). The expense of
upgrading techniques and the technical expertise required are
frequently cited as being inappropriate for developing
countries. Greenhalgh (1984) concluded that in many situations
chemical upgrading will be superceded by breeding more
nutritious straws, improved harvesting methods and judicious
supplementation. The research to be reported suggests another
approach, namely to improve animal productivity from crop
residues by using the selective eating behaviour of goats and
sheep.
The literature on feeding straws to sheep and goats
involves experiments where intake and digestibility have been
measured under ad I ibi tum feeding. Ad libitum is defined as
offering sufficient (usually in chopped form) to ensure that 15
to 20% is left (refused) at the end of the feeding period
(Blaxter et al, 1961). This approach is standard and has the
advantage (for the experimenter, but not the animal) of
minimising selective feeding. We would argue that the latter
is a disadvantage. The capacity of sheep (Gibb and Treacher,
1976) and goats (McCammon-Feldman et al, 1981) to graze and
browse selectively is recognised. Indeed experiments (e.g.
Gibb and Treacher, 1976) indicate that maximum intake by
grazing sheep is achieved only if the herbage allowed (g
organic matter per kg liveweight day, g OM/kg w.d) exceeds
intake by 400%. We therefore hypothesised that conventional ad
I ibi tum feeding of straw, allowing excesses of only 15 to 20%,
would restrict intake (by reducing the opportunity to select).
This hypothesis was tested in the experiments to be
reported.
The experiments are also aimed at helping us develop strategies
for stall-feeding straw to goats and sheep.
MATERIALS AND METHODS
Seven experiments conducted at Reading University during the
past five years are presented. All involved measuring straw
intake (as affected by various parameters) and aimed to assess
the degree of selective feeding, by careful sampling and
analysis of feed offered and refused. Except in Experiment 1
(no concentrate fed), all involved feeding a concentrate
supplement (sugar beet pulp, 600 g/kg; soya bean meal, 180
g/kg; fish meal, 180 g/kg; minerals and vitamins, 40 g/kg) at
15 g DM/kg W ' . d. to satisfy nitrogen, mineral and vitamin
requirements (Agricultural Research Council, 1980) for
maintenance and modest growth in sheep. Numbers of animals
used, type and mean weight are shown in Tables 1 to 7. All
experiments involved housed (16 hours light, 8 hours dark)
individually penned castrated animals bedded on sawdust and
provided with water. In Experiment 6 goats were in metabolism
cages and faeces was collected over 9 days following a
preliminary period of 14 days. In all experiments preliminary
periods were of 14 to 21 days and experimental periods (except
Experiment 6) lasted 21 days (42 days in Experiment 4). Feeds
were offered twice daily and straw refusals carefully collected
daily. Representative samples (based on aliquots) of straw
offered and refused were taken daily and subsequently analysed,
after pooling (Wahed and Owen, 1986), for dry-matter, ash and
nitrogen (AOAC, 1975), acid detergent fibre (Goering and Van
Soest, 1970) and in vitro digestibility (Til ley and Terry,
1963).
RESULTS
Treatments applied in given experiments and results obtained
are shown in Tables 1-7.
Experiment 1 (Table 1) was designed to examine whether
any of the claimed superiority of goats over sheep, in regard
to roughage intake and digestion, could be attributed to
differences in food selected in a stall-feeding situation. The
straw used was treated with aqueous ammonia using a stack
method (Sundstol and Coxworth, 1984). The experiment showed
goats to eat more than sheep, but there was no large difference
between the quality of straw refused by the two species. What
was clear, however, was that both species were feeding
selectively. Refused straw was of lower nutritive value than
that offered.
Table 1.
Experiment 1. Intake and selection of NH,-treated barley
straw by sheep and goats.
Suffolk Saanen SED
cross castrate
Mule goats
wethers
Number of animals
Liveweight (kg)
Straw intake
Offered8 (g DM/d)
Intake (g DM/d)
(g DM/kg W.d)
8 8
57.9 50.7 9.0
1299 1477
956 1117 152.4
16.4 21.6 1.5
Chemical composition Straw offered SE Straw refused
Nitrogen (g/kg DM) 17 0.5 11.6 12.2 0.6
Acid-detergent fibre (ADF)
(g/kg DM) 567 5.7 612 600 6.4
In vitro digestibility
(DOMD)b (g OM/kg DM) 607 6.0 544 566
To allow a refusal rate of 20 to 25% of amount offered.
Til ley and Terry (1963).
Source: Wahed and Owen (1986a).
Experiment 2 (Table 2) was the first trial to test the
hypothesis outlined earlier. Allowing goats to refuse 50% of
the straw offered clearly led to greater DM intake (by 31%)
than allowing the more conventional 20% refusal rate. Refusal
quality indicated goats allowed the higher refusal rate were
selecting more nutritious straw. Thus the estimated intake of
straw digestible OM (based on j_n vitro digestibility) was
markedly higher (by 40%). The goats used (18 / treatment)
represented a wide range of liveweight (15 to 65 kg). Small
goats tended to be more selective than large ones.
In Experiment 3 (Table 3) increasing the refusal rate
allowance increased intake of both long and chopped straw. The
trend (non-significant) was for greater intake of long straw.
Straw length interacted significantly with refusal-rate for
refusal digestibility, indicating easier selective feeding with
long rather than chopped straw. All subsequent experiments
were therefore carried out with long straw.
Experiment 4 (Table 4) simulated the 'grazing approach'
(e.g. Gibb and Treacher, 1976) in that the amount of straw
offered was based on goat weight so as to achieve a target rate
of refusal. The results, however, corroborated those of
Experiments 2 and 3. They also showed, as expected, that
intake response increased with increasing allowance rate. This
was particularly so for the estimated digestible OM intake.
Experiment 5 (Table 5) with sheep showed similar results.
Table2.
Experiment2.Eff ctoallowingtworatesrefusalnint ka dsel ctionoba ytygo s.
1
Numberofgoats
Strawin ake2(gEM/ gW.d)
Strawin ake(gEM/ g000'75.d)
Strawrefused(%ofoffered)
Strawrefus lallowance 20X5 %00E
55
11.4 33.1 20.5
18
18.90.70 43.71.60
48.3
Estimatedintakofr wd gestible
OM3(g/kgW.d)
Ehemicalcompos tionfstraw
5.9
8.3
Strawoffe edStrawrefused
Mean00
Nitrogen(g/kgEM)
50F(g/kgEM)
InvitroEOS4(gOM/kgM)
5.10.024 560.13 5527.061554.8
0024.8320E7.7
.0.75
1.Meanliv weight(W)32.6kg.
2.Eoncentratesupplementalsofedt15gEM/kg00.d
3.Ealculatedfromjnvitrodiges ibilityofst awof eredandre use
4.Tilleyanderry(1503).
Source:WanedandOwen(1986b).
c 01 -C
o u 4-* *J
O- c (J o
U) a c iD
0> 3 01 H-
l_ O —1 •4-
3 i
ID —I
O) C
Q—
a
o
C *-•■ 0) c
Kl E 0)
01
•■- el_ 4-*
01 ID
XI a 111
ID X l-
4-> c
O) O
C •-
V 4-1
X — O
a
I L.
iS 01
L. 4-'
«-> cU) •■-
13
a)
a
1
cID
l- • .—
4-> CO
CO E
H- X
a o
CM
c
I/)i/> o
•o •* o
in M
>o 1o o
•o CO o
•- ^ ■*
•* o
r>- oo
in oo
in co
-* eo >o
o
in cm «-
oo N-
m m
u >. a«— ^1 o- • — l_ a
•o • ■ —' ID o«— fO o- <f Kl M a. C ■IT
C0 o> o U
in ro L.
CO
4-1
cID
4-*
V1
in
o
ID
O)^1\ 3
a.
>^\
-O ID ^s ID Kl ro c^> HI I- X ■ •— o ^O o
XJ l_
01
4-*
V>
a
o u ^^
CK —1
3 H- O) 4-* 1 3 s^/ c •
H- 1O _* O c ^y >-
01 *-*
O) o 01 ^ ID o 01 r-.* i/1 X >+- • — 4^ l_ 3 CO^ **- 3 o y) -C t_ 4-» o-
X o H- *^ CM ■— □1 11 01 • «—
1 o «
oi X O) u • .— 1— ^3 OJ x_^
l_ o \0 X HI HI 4-i
V) O) >-^ l_ 3 T> 01 ID T>
4-* ^^ ■4- O) V* rj a 11 C u l_ 01
id 1O o .* *■* Q > ID c 1 -C
o O) 111 ^ X X •• ID ■ — 01 —■ rD
O) -X W) c O) Q o c —• >* l_ ID 3
ID 3 o w Q O) O) HI 01 <n
H- •*- O) c C 13
o c HI *-> c -X O (/) •— ID —■ H- *4- 01■ '- L. • «- 01 ^ L. HI tfl 01 •»— ■•- 01 o
1_ 1/1 o> Ol *-* Q 3 X )— o l_ L.
111 3 3 o o ^^ • — 3
-Q ID ID a i- > O
e i_ l_ E 4-1 ut «— c\1 f) ^J in in
3 4-* *J o •■— a C
z c/i i/> (-> z < ~
Table4.
12xperiment4.2ffectoamounoff redointakandsel ction
ofbarleystrawygoats.
Dtrawoffered£H/kgW.d)
1154908D
Numberofgoats
Initial(day1)liveweightkg)
Final(d y41)liveweightkg)
Dtrawin ake1(gDM/ gW.d)
Dtrawintake(gM/kgU075.d)
Dtrawrefused(Xoff er )
1
12stimatedin akofr wdigestibleOM( /kgW.d)
Chemicalcompositionfstraw
Nitrogen(g/kgDM)
ADF(g/kgDM)
j_nvitroDOMD(gOM/kg)
0.56 0.11
0.18
1.112 0.11
6.9 14.12
30.4 124.0 16.1 61.3 18.3 14.5
refused 6.1
124 403
11
raw
7
120.6 33.1 11.1 54.1 56.6 11.1
Dt
5.
518 1218
11
1.40 115 5
30.1 30.1 15.5 36.0 11.5
1
5111.065 443.5354
11
Dtrawoffered
Mean18
1.Concentratesupplem ntalsof da5gDM/kgW".
1.Calculatedfromjjnvitrodigestibilityofstrawfferndre used.
12.TitleyandTerr(1"3).
Dource:WahedandOw n(1916b).
i
L.
«
L.
O
g
4-*
%
18
18
L.
01
01 I-
Io X
§
3
N »-
O O CM >*«- •- >o •£
o 1* r*- o
- ^ g CM
s
S■O o"-
c « X
a> O) V5 >^
5 ~ ft ■p
5 -* TJ W■ _ 3
•4- *> ^ H-
O C i) 41w 4-' C
jj 3 1 3
; l- *■* L.
3 4-> V) +>
CM
«- ■* CM
3 s
m «- ■-
CO .O
in ro
in
>* o %j>
5 CM
HI
CO CM O CO
o r^ o
31
id| c
L A >f
(At Z <0 CM CM
-* m
in 1»
s
(A ^> (
M 1O I
TJ O L. (
0>
3 X h- ■*-! »»
£§
CJ>
*s _ _
ai a a
c J* oi
o> rt *-»|
o w —I
>- >l
4-* Ik
i S £1
18
S
•4-
l_
12
IC
O
3 3
CD
O) l_-* *-1
~^. (A
z
o •4-
O)
O
X
u-\ +-*
*-*
-GID
18
**- ft
o ■o
(A
5 ci C .
OI L 01 <-•*- ►— W
V
** 19 TJ *a t> c **
l_ *j (D (D
4-' CO CO
c — >~ 2
0» D 01o o —* ••
S-. _ 01CO •■- u
L) (J 1- L.
«- CM fO •* CO
10
Experiment 6 (Table 6) investigated the feasibility of
refeeding 'stall-grazed straw' , as such, or after treatment
with ammonia (stack method-Sundstol and Coxuorth, 1984).
Intake of untreated ' stall-grazed straw' (straw-previously-
refused) was significantly less than that of the original
straw, but after treatment, the intake of digestible OM
(measured j_n vivo) was the same as the original, untreated
straw.
Experiment 7 (Table 7) was only recently completed and
aimed to assess whether intake and selection response to
increasing refusal allowance would be affected by whether or
not the straw was treated with sodium hydroxide (dip method
according to Sundstol et al, 1981). The preliminary results
are somewhat surprising, indicating no apparent increase in
straw DM intake due to increasing the refusal -al lowance rate.
There was a response to NaOH treatment. In this experiment
samples of straw offered and refused were botanical ly
fractionated (Ramazin et al, 1986). Interestingly, the results
(Table 7) indicate that with generous feeding (allowing high
refusals) intake of leaf plus sheath increased and stem
decreased. As expected with barley straw (Ramazin et al,
1986), Table 8 shows leaf plus sheath to be of higher nutritive
value than stem.
DISCUSSION
The results obtained clearly support the hypothesis sta'ed.
Goats and sheep will consume more barley straw if they are
permitted to reject 50% of that offered, rather than the
conventional 10 to 20%. Furthermore, the improvement in
consumption of digestible straw is even greater because
generous feeding allows animals to select the more digestible
fractions (leaf rather than stem).
There is need to corroborate the findings with direct
measurements (j_n vivo) of digestible straw intake and also
animal productivity measurement. The experiments reported
11
(Tables 1-8) are tedious to execute and offer much scope for
arriving at erroneous conclusions. For example, incomplete
collection of straw refusals would exaggerate treatment
response, as unrecorded refusal would be deemed eaten. Grazing
research techniques (e.g. Mayes et al, 1986) might have
application for measuring quantity and quality of straw
consumed.
The extent to which selective feeding of straw occurs
with higher levels of concentrate supplementation, or when
feeding other forages, needs investigating. Similarly the
effect of straw allowance on consumption and selection of
straws other than barley needs researching. The works of
Capper et al (1986), Tuah et al (1986), Ramazin et al (1986)
and Doyle et al (1986) stress the magnitude of differences
between straws of a given type in terms of feeding value.
Difference in leaf:stem ratios probably accounts for much of
this. There are likely to be other factors e.g. content of
soluble phenolics (Reed, 1986) contributing to nutritive value
differences in some crop residues and other tropical forages.
Interactions between straw allowance rate and straw type, as
affecting intake and selectivity, are therefore likely.
Zemmelink (1986) has clearly shown this to be so for tropical
forages.
12
Table6.
Experiment6.Eigestible-strawin akebygo sfedstr wostraw-previously-refus d,withor
withoutammoniatreatment.
Straw
Straw-previously-refusedbygoats00E
Nunberofgoats"
UntreatedNH,treatedUntr ed
NH,-treated
1.98
4.71 0.90 2.11
19.4
E.3
9.7 23.7
15.8
37.5 6.6 15.6
24.5
58.9 12.6 30.4
22.8
53.9 9.7
.d22.9
Strawin ake
gEM/ka00.d
gEM/kgW.d
gdigestible0M4/kg00.d
gdigestibleOM/kgW0'75
1.Barleyst awfedinExperiments2and4;fetoall w50%rat
ofrefusal;strawchopped.
Eoncentratesupplementalsofed,t15gEM/kgW'.d
2.Strawfrom50%refusalra esinExp rim nts2and4;st w
chopped.Eoncentratesupplementalsofedt15gEM/kgW".d
3.Meanliveweight(W)36.0kg
4..Invivodigestibilitymeasured;conc ntrateOSassumedtob55%
Source:WahedandOwen(1987)
Table7.
Experiment7.ffectore usalratandNaOH-treatm ntfba l yst wonin ke
andselectionbygoats.
straw
20.0 11.2 8.8
50 9 1557 451 502 003 485 559
NaOH- 19.8
7.1 9.4
20 9
1001 451
57
197
S5
612
straw 50 9 1398 449
E7
758 009
S3
16.7 10.6 5.3
Untreated
AO 9 87
449 400 166 3E 67
16.5 6.6 7.1
Strawrefusalallowance(Xoff ered)
Leafpluslsheath(g/kgstrawEM)
Stem(g/kgs rawEM)
Leafpluslshe th(g/kgstrawEM)
Stem(g/kgs rawEM) Total(g00M/kgW.d)
Leafpluslsheath(gEM/kgW.d)
Numberofgoats
Amount(gEM/d)
Straw(g/kgstrEM)
Amount(gEM/d)
Strawconsumed
Stem(gEM/kgW.d)
Strawofferea
1.Saanenc strates,melivew ight(W)00 4kg
2.Eoncentratesupplem ntalsof ,a55gM/kgW*.d
Source:Owenetal,ReadingUniv rsity,ing,00,u p bl shedda a.
Table 8.
Experiment 8. Composition of straw offered.
Untreated straw
Leaf + Stem
leaf sheath
NaOH - straw
Leaf + Stem
leaf sheath
Ash (g/kg DM)
NA (g/kg DM)
ADF (g/kg DM)
DOMD in vitro (g OM/kg DM) 515
28.0 22.0 72.0 44.8
1.7 1.2 21.1 14.5
521 668 501 610
262 664 367
1. Til ley and Terry (1963).
Source: Owen et al, Reading University, Reading, UK, unpublished data.
A feeding strategy allowing goats and sheep to
reject 50% of the straw offered is clearly wasteful
(Table 9) and can only be justified if the rejected straw
can be used too. Experiment 6 (Table 6) demonstrated
that rejected straw can be refed to achieve high levels
of digestible straw intake provided it is treated with
ammonia. Feeding untreated straw to allow 50% refusals
and refeeding these after ammonia treatment would result
in little wastage and would also achieve high intakes of
digestible straw (Table 9). The economics of such a
strategy need investigating as labour costs would be
high. A simpler approach would be to graze the straw in
the field. Ungrazed straw would then be collected and
refed after upgrading.
15
201
o
5
ro
1D
crt
3: 3
z o M-
•cW <u
-C l_
£ S «
3 CD o
ID TJ
0) C
3
5 -_ |
ID (A *+-- 3 H-
O H- 01
4-> 01 i_
10 (/)
3
io *j »e
ID o
— 01 IM
-8 5> M-
—> CO
O £ 3 ?*-1 iU !- ■ —
- ?
ra o d>
w •— v
3 *-' 1*-
H- C
»<o
cM a 181
o o o
o o
2 S
O) cn ^^ CO
n -* z K)^ >~. o in
X z
m
o o o> 01
o o o O) O) o
XI
o o o nJ■
C0 CO
o o
o in in (\1
oo
in *->
^*
XI 01 tM
>-
01
XI
01
XI o
E
3
U)
o o
*-*
c
o
o
XI
4-* *-> l/) 0)
3
ID
3
10
10
3
10
4J
1M
m
(D 1d
l_ l_ 3 ID c
o
o 8 oo O VI
H-
01
l_ 12~
o fM CO ro L. « z
01 01 T3
Q
6
3
E
3
a)
01 01 cn
C/> CO
01
♦-» 01
U)
10c c
10
01^■*
$ o o t- u 01x 1 o u 4-» t_
1=1 to u
a> l_ H- H- H- *♦- c
W t_
(A o o o o
i?
o 18 iu >~ >- >. >- «-'
>^\
!o
w *■* *-> *-* c
i_ 2 X
■*- 01
*-' 3 Q z X 4-» E
c/> CO
5j o s XJ XI XI XI (0
H- *-* ^^ CO 4-» O) 01
o (A -* « •5 +■* *-> 4-* *-* i_
>* (/> cn v> cn in 4J
^
t_ OJ 01 01 01 01 01,*-' o
s -8 J3 o x> O) a> a> o>*-* 3 Q. <«- 3t X) X) T3 •o Z 2c 01
£
4-» 01
Q3 0) s iE s en.2 0> O) tji O) o>
O- i_ IS i_ o> *■• ^ c c c c O) c
l_ *-> c $ jtf—' ••- 01 (/) T3 E E E E \ Eto CO
> *-* >. 3in 3in 3 3 o
3
4-* 1D o to (S
in
in m cn
2 *-> *-»
in in cn in
c => O o 10 < < < < a> <►— >— a
ID xi u TJ 01
16
REFERENCES
Agricultural Research Council. 1980. The nutrient
requirements of ruminant livestock. Commonwealth
Agricultural Bureaux, Slough, UK. 351 pp.
AOAC (Association of Official Analytical Chemists). 1975.
Official methods of analysis. 12th edition. AOAC,
Washington, D.C.
Blaxter, K.L.; Wainman, F.W. and Wilson, R.S. 1961. The
regulation of food intake by sheep. Animal Production 3
: 51 - 62.
Capper, B.S.; Thomson, E.F.; Rihawi, S . ; Temanini, A. and
McCrae, R. 1986. The feeding value of straw from
different genotypes of barley when given to Awassi
sheep. Animal Production 42:337-342.
Devendra, C. and Burns, M. 1983. Goat production in the
tropics. Commonwealth Agricultural Bureaux, Slough,
UK. 183 pp.
Doyle, P.T.; Pearce, G.R. and Egan, A.R. 1986. Potential of
cereal straws in tropical and temperate regions. In :
M.N.M. Ibrahim and J.B. Schiere (eds), Rice straw and
related feeds in ruminant rations. Agricultural
University, Wageningen. pp. 63 - 79.
Fomunyam, R.T. and Meffeja, F. 1986. Maize straw in
maintenance diets for sheep and goats in Cameroon. In
: T.R. Preston and M.Y. Nuwanyakpa (eds), Towards
optimal feeding of agricultural by-products to
livestock in Africa. Proceedings of a workshop held at
the University of Alexandria, Egypt, October 1985. ILCA,
Addis Ababa. pp. 135 - 139.
17
Gartner, J. A. 1984. Report of the FAO Expert Consultation on
Improving the Efficiency of Small-Scale Livestock
Production in Asia : A Systems Approach. FAO, Rome.
Gibb, M.J. and Treacher, T.T. 1976. The effect of herbage
allowance on herbage intake and performance of lambs
grazing perennial ryegrass and red clover swards.
Journal of Agricultural Science (Cambridge) 86 : 355 -
365.
Givens, D.I. 1987. The nutritive value of untreated cereal
straw in the UK - a short review. Agricultural
Progress 62 : 26 - 34.
Goering, H.K. and Van Soest, P.J. 1970. Forage fiber analyses
(apparatus, reagents, procedures, and some applications).
Agriculture Handbook, no. 379. US Department of
Agriculture, Washington, D.C.
Greenhalgh, J.F.D. 1984. Upgrading crop and agricultural by
products for animal production. In: F. M. C. Gilchrist
and R.I. Mackie (eds), Herbivore nutrition in the
subtropics and tropics. Science Press, Pretoria. pp. 167
- 181.
Hartley, B.S.; Broda, P.M. A. and Senior, P.J. (eds). 1987.
Technology in the 1990's: Utilisation of lignocel lulosic
wastes. The Royal Society, London. pp. 405-568.
Mayes, R.W.; Lamb, C.S. and Colgrove, P. 1986. The use of
dosed and herbage n-alkanes as markers for the
determination of herbage intake. Journal of Agricultural
Science (Cambridge) 107: 161-170.
McCammon-Feldman, B.; Van Soest, P. J.; Harvatly, P. and
McDowell, R.E. 1981. Feeding strategy of the goat.
Cornell International Agricultural Mimeograph 88.
Cornell University, Ithaca, New York.
18
Naate, N. M. 1986. Effect of the level of offer on selection
and intake of barley straw by sheep. MSc thesis,
University of Reading, Reading, UK.
Owen, E. 1981. Use of alkal i -treated low quality roughages to
sheep and goats. In: J. A. Kategile, A.N. Said and F.
Sundstol (editors), Utilisation of low quality roughages
in Africa. Royal Agricultural University of Norway,
Aas, Norway. pp. 131-150.
Owen, E. and Kategile, J. A. 1984. Straw etc. in practical
rations for sheep and goats. In: F. Sundstol and E.
Owen (editors), Straw and other fibrous by-products as
feed. Elsevier, Amsterdam. pp. 454 - 486.
Owen, E. 1985. Crop residues as animal feeds in developing
countries - use and potential use. In: M. Wanapat and C.
Devendra (editors), Relevance of crop residues in animal
feeds in developing countries. Funny Press, Bangkok.
pp. 25-42.
Powell, J.M. 1986. Crop- I i vestock interactions in the subhumid
zone of Nigeria. In: R. von Kaufmann, S. Chater and R.
Blench (editors), Livestock systems research in
Nigeria's subhumid zone. ILCA, Addis Ababa. pp. 268
- 303.
Preston, T.R.; Kossila, V.L.; Goodwin, J. and Reed, S.B.
(editors). 1985. Better utilisation of crop residues and
by-products in animal feeding: Research guidelines. 1.
State of knowledge. FAO Animal Production and Health
Paper 50, FAO, Rome. 213 pp.
Ramazin, M.; Orskov, E.R. and Tuah, A.K. 1986. Degradation of
straw. 2. Botanical fractions of straw from two barley
cultivars. Animal Production 43: 271-278.
Reed, J.D. 1986. Relationships among soluble phenolics,
insoluble proanthocyanidins and fiber in East African
browse species. Journal of Range Management 39: 5-7.
19
Sundstol, F. 1981. Methods for treatment of low quality
roughages. In: J. A. Kategile; A. N. Said and F.
Sundstol (editors), Utilisation of low quality
roughages in Africa. Royal Agricultural University of
Norway, Aas, Norway. pp. 61-89.
Sundstol, F. and Coxworth, E.M. 1984. Ammonia treatment. In:
F. Sundstol and E. Owen (editors), Straw and other
fibrous by-products as feed. Elsevier, Amsterdam. pp.
196 - 249.
Sundstol, F. and Owen, E. (editors). 1984. Straw and other
fibrous by-products as feed. Elsevier, Amsterdam. 604
pp.
Tilley, J.M.A. and Terry, R.A. 1963. A two-stage technique for
in vitro digestion of forage crops. Journal of British
Grassland Society 18: 104-111.
Timon, V.M. and Hanrahan, J. P. (editors). 1986. Small ruminant
production in the developing countries. FAO Animal
Production and Health Paper 58, FAO, Rome. 234 pp.
Tuah, A.K.; Lufadeju, E.; Orskov, E.R. and Blackett, G.A. 1986.
Rumen degradation of straw. 1. Untreated and ammonia
treated barley, oat and wheat straw varieties and
triticale straw. Animal Production 43: 261-269.
Wahed, R.A. 1987. Stall-feeding barley straw to goats: The
effect of refusal-rate allowance on voluntary intake and
selection. PhD thesis, University of Reading, Reading,
UK.
Wahed, R.A. and Owen, E. 1986a. Comparison of sheep and goats
under stall-feeding conditions: roughage intake and
selection. Animal Production 42: 89-95.
Wahed, R.A. and Owen, E. 1986b. The effect of amount offered
on selection and intake of barley straw by goats.
Animal Production 42: 473 (Abstract).
20
Wahed, R.A. and Owen, E. 1987. Intake and digestibility of
barley straw by goats: effect of ammonia treatment of
straw and straw-previously-refused by goats. Animal
Production 44: 479 (Abstract).
World Bank and Winrock International. 1983. Sheep and goats in
developing countries: Their present and potential role.
World Bank, Washington, D.C. 116 pp.
Zemmelink, G. 1986. Evaluation and utilisation of tropical
forages. In: M.N.M. Ibrahim and J.B. Schiere
(editors), Rice straw and related feeds in ruminant
rations. Agricultural University, Wageningen, The
Netherlands, pp. 285 - 298.
21
SMALLHOLDER LIVESTOCK PRODUCTION: CONSTRAINTS ON THE
ADOPTION OF IMPROVED TECHNOLOGIES
E.N. Tambi
Institute of Animal Research, Bambui
P.O. Box 80, Bamenda, Cameroon
ABSTRACT
This study made use of information collected from a formal
survey of sheep and goat farmers in the North West Province of
Cameroon to test the hypothesis that the ability of a farmer to
adopt a particular technology with which to increase production
depends on the resources of the farmer, his/her socio-economic
characteristics and expectations as well as factors outside
his/her own control.
The framework of analysis was based on a multistage
economic model of the adoption process relating to agricultural
innovations. A general profit function was estimated by the
method of maximum likelihood to derive coefficients and
probabilities of explanatory variables likely to influence
farmer attitudes towards increased sheep and goat production.
Estimated coefficients showed that current herd size,
available pasture land, housing and fencing facilities, current
income from sales, and market price for sheep and goats had
significant effects on the ability to increase sheep and goat
production through adopted technology. The variables - family
and hired labour, age, and expected future returns from sheep
and goat - did not significantly affect the decision to
increase sheep and goat production. From the interviews, over
80 percent of farmers were willing to increase sheep and goat
production if constraints on production and marketing were
lifted. This suggested that a substantial number of farmers
were being prevented by a number of factors from expanding
production. Against this background of constraints, a strategy
for developing the sheep and goat sectors in the North West
Province should aim at not only minimising constraints against
increased productivity, but also exploiting the biological,
22
economic, management and institutional possibilities available
for sheep and goat production.
INTRODUCTION
Small ruminant production in general, and sheep and goat
production in particular, has in recent years gained increasing
popularity in most of the developing countries. Apart from the
social and economic functions small ruminants play in
developing societies, they also provide most of the meat supply
for human consumption. Increased demand for goat meat for
example provides potential economic advantages to farmers of
small ruminants over large ruminants (Cross, 1974; McDowell and
Bove, 1977). Adu and Ngere (1979) and Brinkman and Adu (1977)
have estimated that sheep and goats contribute 11 and 20
percent of the meat supply in Nigeria respectively, while Bayer
(1986) estimated they supply 35 percent.
The most serious constraint, however, on small ruminant
production in Africa in general and Cameroon in particular is
the small size of the average farm. It is estimated that there
are approximately 20,000 and 57,000 sheep and goat farmers in
the North West Province of Cameroon (18.3 and 13.1 percent of
the national total) with sheep and goat population representing
10.9 and 12.6 percent of the national herd size respectively.
The average herd size per farm is 8.8 sheep and 7.8 goats with
births making up 61.7 and 56.6 percent of the increase in herd
size and mortality accounting for 39.5 and 36.5 percent of the
reduction in herd size respectively (Cameroon Agricultural
Census, 1984). Since the herd size is small, one way of
increasing it is by means of intensification; that is,
increasing output in a way that is economically worthwhile to
the farmer.
The key to intensification and increase in output of
sheep and goat production is the application of improved
production and marketing technologies. These include
significant increases in the use of purchased cereal/protein
feeds (concentrates) including crop by-products (Fomunyam and
Meffeja, 1985) and conserved grasses (Tait, 1973), improvement
23
of existing vegetation by upgrading soil fertility, improvement
of seeding (Newbold, 1974), investments in improved stock
breeds and the application of processing and marketing
techniques. These measures of intensification are difficult to
come by because of low income levels, inadequate resources and
managerial skills as well as general socio-economic
characteristics which, together, constitute production and
marketing constraints in sheep and goat production. The
testing of innovations and monitoring of sheep and goats on
smallholder farms outside the station therefore requires an
understanding of existing constraints relating to available
resources, management practices, ownership patterns as well as
marketing conditions.
This study made use of a formal survey with a pre
designed questionnaire to collect information on these
parameters from a sample of 60 sheep and goat farmers in the
North West Province of Cameroon. This was being done as a
follow-up of a diagnostic survey of sheep and goat farmers
carried out as part of the IRZ-IDRC on-farm research project.
Given the several production and marketing constraints
identified in that survey, it was observed that most sheep and
goat farmers were reducing the number of animals they keep and
were shifting towards crop production which seemed to offer a
better alternative to subsistence life.
Based on these findings, it was hypothesised that the
ability of a farmer to adopt a particular technology with which
to increase productivity depends on the resources he/she has
available, his/her socio-economic characteristics as well as
those factors outside the farmers' own control. To the extent
that these constitute constraints to the farmer, they will
affect his ability to adopt the technology and therefore his
ability to expand his farm size. The object of this paper
therefore is to correctly identify those factors which
influence the farmers' decision to increase production through
improved technology.
24
MODEL
A farmers' attitude towards sheep and goat production is
influenced by his resources, his socio-economic characteristics
and expectations, and also the attributes of the present and
alternative job opportunities available. The model used in
analysing these factors is based on previous research
concerning factors influencing the adoption of agricultural
innovations (Kennedy, 1977) generally, and on explanatory
variables identified from research specific to constraints on
sheep and goat production and marketing in Africa (Lebbie and
Mastapha, 1985; Tambi and Fomunyam, 1985).
The procedure used to measure farmer response to
increased sheep and goat production was to utilise binary as
well as non-binary variables to quantify factors likely to
influence the positive/negative attitudes of farmers towards
sheep and goat production. The economic framework rests on a
multistage model of the adoption process relating to
agricultural innovation (Leuthold, 1966; Kennedy, 1977; Hill
and Kau, 1973; McFadden, 1976 and Opare, 1977). In the model,
the farmer is confronted with a choice (to expand his/her sheep
and goat operation or not to do so) to which he/she reacts
positively or negatively depending upon his/her resources,
expectations and socio-economic characteristics. The task is
to quantify factors (Table 1) which influence this decision.
The probit procedure (Hill and Kau, 1973 and Turner et
al, 1983) which specifies a binary dependent variable as a
function of a number of quantitative explanatory variables
(Kmenta, 1971 and Gujarati, 1978) was chosen for use here
because of its ability to generate bounded probability
estimates for each individual farmer. The model can be
specified as :
n
Y. = a + b Xj + E. (1)
i = 1
where the X-s represent vectors of n(n=9) explanatory variables
of the i farmer, and Y- is a binary variable such that
25
Y- = 1 if the i farmer wants to expand production = 0 otherwise.
In the model, the X.s are assumed to be stochastic and
independent of the zero mean random variable E-. Since Y. can
only assume two different values, 0 and 1, the following
expected probability can be obtained:
ECYj) = 1X#|C1) + OXf^0) = f.<1) (2)
where f.(1) is the probability that a farmer with a set of
resources and economic characteristics (X.) would expand his
operation. From (1) and (2),
n
E(Y.) = a + X. (3)
1 = 1
meaning that the probability f-(1) would be different for
farmers with different levels of resources and economic
characteristics. Thus, the expected probability E(Y.) which
can be interpreted to mean the proportion of all farmers with
resources and economic characteristics (X.) likely to expand
operation would be given by:
n
0< a + b X. < 1
i = 1
The larger the proportion the greater the decision to expand
operation and vice versa.
Following Turner et al (1983) the general probit form
for the i farmer is :
INT ■ f(HDS, PLD, HOU, LAB, FNC, PRI, GIN, AGE, EXP)
where the independent variables are defined as in Table 1 and
INT is a hypothetical index signifying the farmers' intention
to expand his sheep and goat farm or not to do so. The maximum
likelihood technique (Kmenta, 1971; Gujarat i, 1978) was used to
estimate coefficients and to test hypotheses about factors
relevant in shaping farmers' attitudes towards expanding sheep
and goat production.
26
Table 1. Variables hypothesised to influence farmer attitudes
towards increased sheep and goat production in the
North West Province, Cameroon.
Variable
name Description Measurement Mean
Expected
impact
HDS Herd size (no. of
animals available on farm)
PLD Land area containing
pastures for grazing
HOU Housing facility for
sheep and goats
LAB Labour resources
(no. of hired and
family labour)
FNC Fencing facility
for confining sheep
and goats.
FRI Current market price
for sheep and goats
GIN Gross income from
sheep and goat sales
AGE Age of farmer
EXP Farmer's expectation
of future farm
income
Actual number of
animals reported 16 .05
No. of hectares
of pasture land
reported 8 .00
1 - housing
avai I able
0 - no housing
avai I able 0..85
Actual number of
persons working
on farm at least
half time 2,.25
1 - Fencing
avai lable
0 - no fencing
avai lable 0..85
Actual market
price observed
per live adult
animal (CFA) 11..975
Actual gross
income reported
from sales of
sheep and goat
(CFA) 44,.800
Actual age of
farmer reported 46..45
1 - r i s i ng
0 - falling
0.55
1US$ = 315.5 CFA
27
RESULTS
Estimated coefficients obtained from the likelihood function
specifying explanatory variables likely to influence farmers'
attitudes towards increased sheep and goat production in the
North West Province of Cameroon are given in Table 2. Current
herd size (HDS) was hypothesised to be inversely related to the
decision to expand production because the probability of a
positive response increased for farmers with smaller herd sizes
and vice versa. At P<0.10 the results in Table 2 supported
this hypothesis. Sample data obtained on farmer response bear
this out since farmers with fewer animals showed a greater
desire to increase herd size to fulfil household cash needs
while farmers with larger herd sizes were not only constrained
by land and pasture shortages (particularly in the dry season),
but also by problems of marketing.
Available pasture land (PLD) was an important positive
factor influencing farmers' attitudes towards increased sheep
and goat production. The results supported the hypothesis that
farmers who have grazing land were more apt to increase herd
size than those with little or no pasture land.
Two other factors that seemed to influence farmers'
attitudes were facilities available for housing (HOU) and
fencing (FNC) sheep and goats. These variables exerted, as
hypothesised, a positive influence on attitudes. Existing
housing and fencing facilities provide positive environments
for improved management of small ruminants. Most farmers
interviewed in this survey provided housing (68 percent) and
fencing (54 percent) for their sheep and goats. This agrees
with the findings of Agyemang et al (1985) who reported 82
percent of farmers housing sheep in the Ethiopian highlands.
28
Table 2. Coefficient estimates, student t's and probability
levels of farmers exhibiting positive attitudes
towards increased sheep and goat production in the
North West Province, Cameroon.
Estimated
Explanatory coefficients Student
variables (standard errors) t's
Probabi li ty of
farmer exhibiting
a positive response
HDS 0.30
(0.021)
PLD 0.015
(0.009)
HOU 0.876
(0.663)
LAB -0.170
(0.234)
FNC 0.210
(0.125)
FRI 0.731
(0.347)
GIN 0.073
(0.038)
AGE 0.37
(0.030)
EXP -0.386
(0.566)
Constant 1.179
degrees of
freedom 8
1.428
1.667
1.320
•0.727
1.680
2.107
1.932
1.224
0.682
0.210
0.204
0.196
0.130
0.220
0.310
0.240
0.141
0.072
Available family and hired labour (LAB) was hypothesised
to be positively related to increased production. Households
with a larger work force are more apt to increase production as
this makes the task for tethering, herding, feeding etc easier.
The results did not support this hypothesis. The variable had
29
the wrong sign and was not significant (P>0.05). This is not
surprising, however, given that family labour, which makes up
the largest chunk of the labour force in subsistence
agriculture often is shared among different alternative farm
activities (see for example Jones, 1983). Assuming from neo
classical theory that household members do not have conflicting
interests over the allocation of labour time for farm work, the
contrary was observed for sheep and goat farmers in the North
West Province. As became apparent through interviews with men
and women and observations, there was frequent and sometimes
pronounced conflicts between men and women over the division of
labour for crop and livestock production. In the North West
Province sheep and goats are tended mostly by men while women
are concerned more with crop production (Tambi and Fomunyam,
1985). Although children assist on the farm, this often is
restricted to vacation periods (June to September). It is
probable therefore, that the combined effects of the division
of labour together with this variable's correlation with other
variables in the equation might have biased the results.
AGE was hypothesised to be inversely related to the
probability of a positive response because older persons tend
to be less vigorous on the farm than younger ones. The results
obtained here did not verify this because AGE was not
significantly (P>0.05) affecting the decision to expand
production. From the interviews, older men seemed to have
preferred having larger herd sizes. The results reported here
did not agree with the findings of Glazner and Sporleder (1979)
who showed AGE to be significantly affecting producer attitudes
towards a computerised feeder cattle marketing nor did they
agree with those of Turner et al (1983) on the effect of AGE on
producer attitudes towards multi commodity electronic marketing.
The variables gross income (GIN) and the expected income
potential (EXP) from sheep and goat production (proxies for
initial capital and future returns) were hypothesised to
directly influence farmers' attitudes. That is the more income
a farmer has and the more optimistic he/she is about future
returns, the more likely will he/she have a positive attitude
towards increased production. Only GIN was statistically
30
significant (P<0.05) indicating that the proxy for initial
capital has a major effect on the decision to increase
production. By implication, any commercially oriented approach
to sheep and goat production will require substantial initial
cash inputs to purchase more animals, for better housing,
improved pastures and the necessary infrastructure (Lebbie and
Mastapha, 1985). The average gross income of 44,800 CFA
reported per farmer is too low to meet these costs. The
variable EXP was not only insignificant (P>0.05) but had the
wrong sign; an indication that higher anticipated returns do
not necessarily influence farmers to invest to increase
production particularly if the investments are associated with
higher levels of risks (Tambi, 1985). Of the farmers
interviewed, only 36 percent indicated that they would increase
production if future income from sheep and goat production
proved good.
Current market price (PRI) was another variable tested
and found statistically significant at P<0.05. It was expected
a priori that the levels of current market prices would exert
either a positive or a negative force on the decision to
increase herd size depending on whether they are relatively
higher or lower than the previous year's price.
The likelihood estimates shown in Table 2 give an
indication of farmers' response to constraints (explanatory
variables) affecting his/her decision to expand production
through improved technologies. The estimates were used to
derive the probability of a farmer reacting positively towards
the expansion of production. To obtain this probability the
mean values of the explanatory variables in the equation were
used to arrive at the value to the dependent variable, which
in turn was used to derive the probability of a positive
reaction towards increased sheep and goat production. These
probabilities are shown in Table 2.
DISCUSSION
The random sample of sheep and goat farmers in the North West
Province, Cameroon revealed that over 80 percent of those
31
interviewed were willing to expand production if constraints on
production and marketing were lifted. This suggested that a
substantial number of farmers were being prevented by several
factors from expanding production. The average herd size of 11
for example, provided limited scope for a commercially oriented
approach to sheep and goat production in the North West
Province. A market-oriented approach, if it is to be of
practical value, must take account not only of the biological
(nutrition and health) possibilities, but also, of a variety of
economic and management constraints. Economic constraints have
a major effect on the extent to which some of the biological
factors can be employed. It is, for example, technically
possible to improve the nutrition and health of animals by
concentrate supplementation and other management factors, but
the relationships between input costs and product prices serve
to limit their use. Dry season supplementation of sheep and
goat diets for example, offers an effective means of increasing
output during periods of scarce pastures but the high
concentrate and labour costs incurred render it uneconomic.
Land and pasture improvement for sheep and goat
production is an expensive operation particularly in regions
where there is dominance of native pastures (Newbold, 1974;
Eadie and Maxwell, 1975). Studies by Maxwell et al (1976)
have shown clearly that beyond a certain point investments in
land improvement for development of improved systems of
production can lead to severe disadvantages to the enterprise
concerned. This is more so when labour and capital costs are
high as a proportion of total cost. In the sheep and goat
production system of the North West Province capital for the
purchase of additional stock is lacking and skilled labour for
management is a scarce commodity so that improved systems must
seek to provide a framework within which capital and labour can
be more efficiently used.
1 US$ * 315.5 CFA
32
Against this background, a strategy for developing the
sheep and goat sector in the North West Province, if it is to
be successful, should aim at fully exploiting the animal, human
and land resources by removing or minimising the current and
future constraints against improved productivity. There is a
need to move away from traditional methods by intensifying
production through the adoption of simple techniques of
improved feeding, more efficient health regime, and improved
marketing services and facilities. Although more research into
the economic viability of feeding concentrates, use of improved
pastures, controlled breeding, health maintenance and marketing
is needed to provide a stronger base for any development
programme, it is important that before the programme is drawn,
the economic consequences of investments in intensive sheep and
goat production be known.
REFERENCES
Adu, I.F. and Ngere, L.O. 1979. Indigenous sheep of Nigeria.
World Review of Animal Production 15 (3): 51-67.
Agyemang, K.; Negussie Akalework, Voorthuizen, K. and Anderson,
F.M. 1985. A rapid survey of sheep production in the
traditional sector of Debre Berhan, Ethiopian highlands.
In: R.T. Wilson and D. Bourzat (eds), Small ruminants in
African agriculture. Proceedings of a Conference held at
ILCA, Addis Ababa, Ethiopia, 30 September - 4 October
1985. ILCA, Addis Ababa. pp. 174-185.
Bayer, W. 1986. Traditional small ruminant production in the
subhumid zone of Nigeria. In: R Von Kaufmann, S Chater
and R Blench (eds), Livestock systems research in
Nigeria's subhumid zone. Proceedings of the Second
ILCA/NAPRI Symposium held in Kaduna, Nigeria, 29 October
- 2 November 1984. ILCA, Addis Ababa, Ethiopia, pp. 141-
166.
Brinkman, W.L. and Adu, I.F. 1977. The problems of goat
production in the savannah region of Nigeria. NAPRI
(manuscript), Zaria. Cameroon, Agricultural Census, 1984.
33
Cross, E.G. 1974. Goat marketing in Rhodesia. Rhodesian
Agricultural Journal 71 : 159-160.
Eadie, J. and Maxwell, T.J. 1975. Systems research in hill
sheep farming. In: G.E. Dalton (ed), Study of
agricultural systems. Applied Science Publishers Ltd,
London, UK. 441 pp.
Fomunyam, R.T. and Meffeja, F. 1986. Maize stover in
maintenance diets for sheep and goats in Cameroon.
In: T.R. Preston and M.Y. Nuwanyakpa (eds), Towards
optimal feeding of agricultural by-products to livestock
in Africa. Proceedings of a workshop held at the
University of Alexandria, Egypt, October 1985. ILCA,
Addis Ababa, Ethiopia, pp. 135-139.
Glazner, G. and Sporleder, T.L. 1979. Potential producer
acceptance of electronic marketing of feeder cattle in
Texas. Agricultural Market Research and Development
Center. Res. Rep. MRC 3-79.
Gujarat i, D. 1978. Basic econometrics. McGraw-Hill Book Co.,
New York, N.Y.
Hill, L. and Kau, P. 1973. Application of multivariate probit
to a threshold model of grain dryer purchasing decisions.
American Journal of Agricultural Economics 55: 19-27.
Jones, C. 1983. The mobilisation of women's labour for cash
crop production: A game theoretic approach. American
Journal of Agricultural Economics 65: 1049-1054.
Kennedy, L. 1977. Evaluation of a model building approach to
the adoption of agricultural innovations. Journal of
Agricultural Economics 28: 55-60.
Kmenta, J. 1971. Elements of econometrics. Macmillan Press.
Lebbie, S.H.B. and Mastapha, P.R. 1985. Goat production in the
Swaziland middleveld. In: R.T. Wilson and 0. Bourzat
(eds), Small ruminants in African agriculture.
Proceedings of a conference held at ILCA, Addis Ababa,
Ethiopia, 30 September - 4 October 1985, ILCA, Addis
Ababa, Ethiopia. pp. 225-234.
Leuthold, F.D. 1966. Communication and diffusion of improved
farm practices in two northern Saskatchewan farm
communities. Canadian Centre for Community Studies,
Saskatoon, Saskatchewan, Canada.
34
Maxwell, T.J.; Eadie, J. and Sibbald, A.R. 1976. Economic
appraisal of investments in hill sheep production.
Rept. 6 H F RO: 24- 42.
McDowell, R.E. and Bove, L. 1977. The goat as a producer of
meat. (Cornell Int'l Agric. Mimeo.) Cornell University
Press, Ithaca, New York.
McFadden, D. 1976. Quantal choice analysis: A survey. Ann.
Economics and Soc. Measure 5: 363-390.
Newbold, P. 1974. The improvement of hill sheep for
agriculture: A review. Journal of British Grassland
Society 29: 241 and 30: 41.
Opare, K.A. 1977. The role of agricultural extension in the
adoption of innovations by cocoa growers in Ghana. Rural
Sociology 42: 72-82.
Tait, R.M. 1973. The utilization of dried grass by early
weaned lambs. Journal of British Grassland Society 27
(4): 217-220.
Tambi, E.N. 1985. Income risk in livestock and poultry
production: The case of dairy and egg production in
the North West Province of Cameroon. Review of Science
and Technology 1 (4): 31-38.
Tambi, E.N. and Fomunyam, R.T. 1985. Survey of sheep and goat
production and marketing systems. By-products Cameroon
Progress Report, 1985-86.
Turner, S.C.; Epperson, J.E. and Fletcher, S.M. 1983. Producer
attitudes toward multicommodi ty electronic marketing.
American Journal of Agricultural Economics 4: 818-822.
35
CONSIDERATIONS IN THE DESIGN OF ON-FARM
LIVESTOCK EXPERIMENTS AND EVALUATION OF RESULTS
G.I. MIay and N.A. Urio
Departments of Rural Economy and Animal Science and
Production, Sokoine University of Agriculture,
P.O.Box 3004, Morogoro, Tanzania
ABSTRACT
The paper identifies major extraneous factors which can have a
significant effect on the variation of response variables in
on- farm livestock research. The implications of such factors
on the design of experiments and evaluation of results are
discussed. Important statistical considerations are presented
and their importance in guiding experimental designs
demonstrated. The paper uses a case study based on a feeding
trial of dairy cattle under small farms to illustrate the
design, management and evaluation problems resulting from the
extraneous factors. A case is put forward to support the use
of farmer-evaluation and economic analysis as additional
approaches to statistical methods in evaluating research
results.
INTRODUCTION
On-farm research can be considered as an intermediate step
between station level research and development. Interest in
on-farm research has arisen out of difficulties encountered in
the large-scale extension of technical innovations developed
under controlled research environment. The rate of adoption of
such technologies has been particularly disappointing in the
case of small farmers (Jouve and Mercoiret, 1987).
The movement of a research process from a controlled
laboratory environment to farm conditions entails additional
considerations in experimental design and the evaluation of
research results. Not only does the process introduce more
extraneous factors whose control may be difficult, but an
additional dimension, the farmer, has to be considered.
36
Arbodela (1987) identifies the researcher, technology, the
farmer and farmer's values as important components in on-farm
research. While the researcher makes his recommendations based
on an objective evaluation of the results arising from the
methodology used in the research, the farmer makes a decision
about the recommendation on the basis of an overall assessment
of the research in the light of his values (Arbodela op. cit.).
Devendra (1987) identifies the following shortcomings
based on experiences from Asian countries: "that methodologies
presently used are haphazard, lack sophistication and control
and are unimaginative; the nature of the work does not allow
for statistical analyses of the results; and ad-hoc innovations
are often imposed in the hope of demonstrating causes and
effects, usually in quantitative terms". These shortcomings
are a reflection of the special problems encountered at farm
level which make a direct transfer of on-station research
approaches difficult or very costly to implement.
This paper highlights the problems of experimental
design of dairy cattle feeding trials and proposes alternative
evaluation criteria where formal designs cannot be implemented.
EXTRANEOUS FACTORS TO BE CONSIDERED IN ON-FARM
LIVESTOCK EXPERIMENTS
Inferences made about population parameter variables measured
in experiments can be seriously affected depending on how
extraneous factors are handled in a design. If a researcher
completely ignores extraneous factors, then the variation that
cannot be accounted for by treatments will be lumped together
as error. Since the error mean square is involved in computing
test statistics, this may lead to wrong inferences. In
addition when significant extraneous factors are ignored, the
usual assumption of homoscedastic error term is no longer valid
and hence variance estimates and test statistics computed from
such data will be biased. Therefore the usual practice is to
attempt to stratify the experimental units on the basis of non-
experimental factors which are thought to show significant
variation across the experimental units. These are
37
subsequently separated from the error sum of squares components
in the analysis.
In on-farm livestock research, where weight gain or milk
yield are the key response variables to be measured, the
extraneous factors which the researcher will have to contend
with may include: location (when the area being covered shows
large climatic variation), breed, time, age, stage of
lactation, lactation number and differences in the level of
management across farmers.
The larger the number of extraneous factors to be
handled in an experiment, the more complex the design becomes
and the requirements in terms of resources also increase. In
addition, interpretation of results become difficult
particularly when interactions of higher orders are involved.
STATISTICAL CONSIDERATIONS
In order to apply statistical methods in data analysis and to
make statistical inferences from the results, the design of
experiments must satisfy the following conditions (Anderson and
Mclean, 1974):
- The inference space must be defined. These are the limits
within which the results will apply. The definition of an
inference space will determine a relevant sample size to use.
- The experimental units must be randomly selected. Random
selection is necessary to protect against bias in the
experiment which could be the result of some unknown factor
having had prior influence on the experimental units in some
systematic fashion. When the experimental units turn out not
to be homogeneous then stratification based on some inherent
characteristic(s) will be necessary.
- Assignment of treatments to experimental units likewise must
be random.
38
With the assistance of a statistician, a mathematical model
evolving as a result of the problem to be studied, factor
levels to be used in the experiment and the conditions listed
above needs to be written down. The mathematical model will
give rise to the ANOVA table which at this stage will consist
of degrees of freedom, and expected mean squares for each of
the specific factors selected. The expected mean squares
will provide information on the various factors which will
have tests available. The researcher can review the ANOVA
table and if some of the assumptions and conclusions implied
by the table are not realistic or practical, the design will
have to be changed.
- Extreme care in data collection is essential. Other factors
given, the success of a scientific investigation depends
upon the validity of all data obtained.
In the light of the farm conditions under which
livestock trials have to be conducted, it is clear that either
some of the conditions listed above will be violated or high
costs will have to be incurred in terms of both financial and
human resources in an attempt to satisfy the stated conditions.
EXPERIENCES WITH DAIRY FEEDING SYSTEMS PROJECT:
HAI DISTRICT - TANZANIA
Smallholder farmers in Hai District keep an average of 4 heads
of cattle per household. These are mainly cross breeds (Zebu
crossed with exotic dairy cattle) and a few pure breeds, mainly
Jersey cattle. In a diagnostic survey conducted in 1984, one
of the factors identified as constraining smallholder dairy
production was the availability of adequate feeds in terms of
quantity and quality. After some assessment of feeds situation
in the district, it was decided to test the impact of
introducing bean haulms/chaff and molasses-urea mixture in
basal rations on milk yield under smallholder farmer
condi t ions.
39
The problems that arose with regard to the design of
experiments were (a) several levels of a factor could not be
implemented within a household; (b) the dairy cattle being kept
varied in breeds/crosses and age, and were at different stages
of lactation. Often the farmers were unable to provide an
accurate history of their cattle; (c) the basic management,
including housing and feeding varied across households; (d) the
fact that the project site is 500 km from the home base meant
that the day-to-day management of experiments and keeping of
records was to be left under the control of farmers. That the
success of the experiments depended on the willingness and the
ability of the farmers to manage the trials meant that
purposive selection of farmers and hence the cattle
(experimental units) was unavoidable.
Ideally the experiments would need to satisfy the
statistical considerations mentioned earlier and the blocking
for the above extraneous factors would be necessary. If these
were satisfied, a linear model of the following form would be
speci f ied:
Y i j k I mno = A + B . +C(.)j+D.+E. +F + G +H
+ (Interactions) + Eijklmno
Where = Yijklmno is milk yield of the jth cow of the k
breed, in 1 lactation, managed by the m farmer in
n location, fed i ration on the o day.
A is the overall mean
Bi is the effect of the i ration on milk yield
C(i) j is the effect of the j cow on the i ration
D. is the effect of the k breed
k th
E. is the effect of the 1 lactation
F is the effect of management by m farmer
m th
G is the effect of n location
n th
H is the effect of the o day
Eijklmno is the error term
The model as presented is still too basic.
Considerations by an animal scientist on important interactions
are essential, and thereafter, practicality of implementing the
40
experiment will need to be considered. Where restrictions are
necessary, these will have to be introduced in the model as
restriction errors since these have an important implication on
the resulting ANOVA table and the tests which will be
subsequently available.
The actual feeding experiments conducted did not satisfy
the criteria mentioned, and therefore subjecting the data to
statistical analysis and drawing inferences from that basis is
not warranted. The design adopted reflected practical
considerations in the project site and resources at the
disposal of the researchers. In addition, researchers were
satisfied that the trade-off between design quality and
developmental effects of the research was worthwhile in the
initial stages of the work.
MATERIALS AND METHODS
Participating farmers were purposely chosen from three
villages: 10 from Ng'uni, 5 from Mowo-Njamu and 5 from Wandri.
Discussion was held with the farmers on the objectives of the
experiments and the tasks they were expected to perform.
Information was sought on the history of the cattle they kept.
For practical reasons, the farmers were to continue with their
usual feeding routines, only that supplementation with
molasses-urea mixture sprinkled on bean haulms was introduced.
Molasses-urea mixture and bean haulms were provided at cost.
Daily feeding of the latter two feeds was at the rate of 2 kg
and 8 kg per animal respectively. Farmers were asked to
record, on a daily basis, milk yield, types of basal feeds
being used and types and quantities of other concentrates fed.
The experiment was continued for a period of 6 months.
Analysis and evaluation of results
The design used suffered from the following weaknesses:
(a) The effects on milk yield of other diets whose feeding
varied within and across households were not controlled or
accounted for the design.
41
(b) The design lacked control treatment.
(c) Only one level of the factor was considered.
As a result of the above weaknesses, it was not possible to
assess the treatment effects on milk yield through statistical
methods.
A subsample of the data collected is used here to
illustrate the importance of controlling or accounting for
extraneous factors when designing on-farm trials. The results
were based on one-way analysis of variance by cow, farmer,
breed, village (location) and ration. The results are presented
in Tables 1 to 5. It is shown that with the exception of
location (village), all other factors have significant effects
on the variation of daily milk yield at 0.01 probability level.
Table 1. Average daily milk yield by cow.
Cow no. Mean yield Standard No. of
(litres) deviation records
1 5.6 0.8 35
2 2.2 0.5 35
3 4.0 0.6 30
4 10.3 1.3 30
5 11.4 1.4 28
6 7.2 0.8 21
7 8.9 1.5 21
8 3.1 0.5 23
9 7.2 1.0 35
10 10.2 1.5 33
11 5.2 1.0 18
12 7.8 0.8 20
13 7.5 1.3 27
42
1.8 70
3.5 88
1.5 42
0.5 23
1.0 18
0.8 20
1.3 27
1.0 35
1.5 33
Table 2. Average daily milk yield per cow by 9 farmers.
Farmer Mean yield Standard Samples
(litres) deviation size
1 3.9
2 8.5
3 8.1
4 3.1
5 5.2
6 7.8
7 7.5
8 7.2
9 10.2
Table 3. Daily average milk per cow by breed.
Breed Mean yield Standard Sample
(litres) deviation size
3.2 153
1.0 168
2.2 35
Table 4. Average daily milk yield per cow in two
vi 1 1 ages.
Village Mean yield Standard Sample
(litres) deviation size
Ng'uni 7.0 3.2 291
Mowo-Njamu 6.9 1.5 65
Jersey 8.6
Friesian 7.3
Crosses 5.4
43
2.1 33
3.2 248
2.1 75
Table 5. Average daily milk yield per cow by ration.
Ration Mean yield Standard Sample
(litres) deviation size
Only molasses-urea 5.7
Cottonseed cake plus
molasses-urea 7.4
Wheat pol lard plus
molasses-urea 6.0
PROPOSALS FOR EVALUATING RESULTS WHEN STATISTICAL
METHODS ARE INVALID OR INADEQUATE
From experience in the Dairy Feeding Systems Research Project,
it is proposed that farmer-evaluation of the research, and
economic evaluation of benefits and potentials for development
should always be either in conjunction with statistical
methods, or on their own when statistical methods are invalid.
Farmer-evaluation is important particularly when it is
considered that recommendations from on-farm research are
expected to be a basis for development of technologies for
adoption. As pointed out earlier, farmer-evaluation takes into
account other dimensions which are not handled by statistical
methods. A survey carried out at the end of the experiment
which covered both participating and non-participating farmers,
showed that the research was addressing an important problem
and that there had been a positive impact on milk yield
performance. The results of the survey are summarised in
Tables 6 to 10.
An economic analysis of on-farm research can take
several forms. The simplest analysis is that restricted on
costs and returns. In order to examine input-output
relationships and resource use efficiency of research trials a
44
production function approach can be used. In the cases where a
farmer is involved in several enterprises (crops and livestock)
budgeting and linear programming techniques can be used to
arrive at optimum combination of enterprises and employment of
various resources. Mdoe (1986) using a multiperiod linear
programming model was able to demonstrate the effects of
alternative dairy production technologies on optimum enterprise
combinations and farm incomes in Hai District.
Table 6. Impact of the research project on dairy management,
Management practices Number of farmers
Ng'uni Mowo-Njamu Wandri Total
No change in management
Record keeping
Use of molasses
Measuring milk production
Chopping of maize stover
Increase use of crop residues 1
Pasture management
1 0 0 1
8 3 2 13
7 5 4 16
3 2 2 7
1 0 1 2
0 0 1
0 1 0 1
Table 7. Dairy cattle performance.
Percentage of farmers
Ng'uni Mowo-N jamu Wandri
Performance remained
the same 0
Performance improved 100
Performance declined 0
20
80
0
0
100
0
45
Table 8. Ng'uni vallage: milk yield before and during the
project period (litres).
Farmer Yield before Yield during Change
number project project in yield
1 6.5 8.0 1.5
2 4.0 5.0 1.0
3 4.5 5.0 0.5
4 4.0 5.5 1.5
5 6.0 7.0 1.0
6 4.0 4.5 0.5
7 3.0 4.0 1.0
8 5.0 6.0 1.0
9 4.0 5.0 1.0
Total 41.0 50.0 9.0
Mean 4.5 5.5 1.0
S.D. 1.10 1.3 0.4
Table 9. Mowo-Njamu: Milk yield before and during project
period (litres).
Farmer Yi eld before Yie Id during Ch ange
number th e project the project in yield
1 6.0 7.0 1.0
2 7.0 8.0 1.0
3 5.0 6.5 1.5
4 3.0 4.0 1.0
5 3.0 4.0 1.0
Total 24 29.5 5.5
Mean 4.8" 5.9 1.1
S.D. 1.8 1.8 0.2
46
Table 10. Wandri village milk yield before and during the
project period (in litres).
Farmer
number
Yield before
the project
Yield during
the project
Change
in yield
7.0
5.0
5.5
3.5
8.5 1.5
6.0 1.0
6.5 1.0
4.5 1.0
25.5 4.5
6.4 1.1
1.7 0.3
Total
Mean
S.D.
21.0
5.3
1.4
REFERENCES
Anderson, V.L. and Mclean, R.A. 1974. Designs of experiments:
A realistic approach. Marcel Dekker, Inc., New York. 418
pp.
Arboleda, C.R. 1987. Methodological and institutional
considerations in applying statistical approaches to on-
farm animal research. In: Proceedings of a workshop on
on-farm research/extension and its economic analysis, 19-
23 January 1987. Southeast Asian Regional Centre for
Graduate Study and Research in Agriculture, Los Banos,
Laguna, Philippines. pp. 77-73.
Oevendra, C. 1987. The relevance of on-farm animal production
research in Asia. In: Proceedings of a workshop on on-
farm research/extension and its economic analysis, 19-23
January 1987, Southeast Asian Regional Centre for
Graduate Study and Research in Agriculture, Los Banos,
Laguna, Philippines. pp. 13-18.
47
Jouve, M.P. and Mercoiret, M.R. 1987. Research and
development: A method of putting farming systems at the
service of rural development. Paper presented at the
Agrarian Systems Seminar, 19 May 1987, Montpellier,
France.
Mdoe, N.S. 1986. An economic analysis of alternative dairy
feed management systems in the highlands of Kilimanjaro,
Tanzania. M.Sc. thesis, University of Guelph, Ontario,
Canada.
48
THE ECONOMICS OF PEASANT CATTLE FEEDING IN MALI
1 2
H. Baur , K. Sissoko and S. Debrah
ILCA, BP. 60, Bamako, Mali
Universitat Hohenheim, 7000 Stuttgart 70, West Germany
2
Projet Sectoriel de I'Elevage de Mali, ILCA, BP. 60, Bamako, Mali
ABSTRACT
On-farm cattle feeding activities of selected peasant farmers
in the semi -arid zone of Mali were followed in the dry seasons
of 1984, 1985 and 1986 under the "Embouche paysanne" project,
financed jointly by the Government of Mali and the USAID. The
abattoir-destined cattle were sample-fed for 80 to 90 days
during the dry season and were sold in May when prices were
high. Coarse fodder and cottonseed cake were the main feed
inputs, and producers benefited from loans provided especially
for the project.
The animals gained on average between 0.58 and 0.81 kg/day
during the feeding period. Gross returns of approximately
25320 CFA and 35319 CFA on average were realised in 1984/85
and 1985/86 respectively by the sample taken as a whole.
Disaggregating the gross returns into its price and weight
components, higher sale prices in May during the 3-year
campaign contributed on average about 55% while weight gains
and the interactions between weight gains and price changes
accounted for 37% and 8% respectively. However, after deducting
purchase and production costs, average profit per animal
including the value of unsold animals was substantially
reduced, affecting the ability of participants to repay loans.
In 1985 for example, about 27% of the sample made no profit or
lost money in the cattle-feeding programme.
Since the fattening programme depended largely on
cottonseed cake of limited long-term availability, feed trials
were undertaken to determine the economic viability of the
* 1 US$ = 315.5 CFA
49
project using reduced amounts or partly replacing cottonseed
cake with other farmer-produced supplements. Although cattle
fed reduced amounts of cottonseed cake gained less weight than
those on larger quantities, profitability was increased.
INTRODUCTION
The general absence of good quality feed during the long dry
season is a major constraint faced by livestock producers
particularly in the arid and semi-arid areas of West Africa.
Research efforts to match seasonal fluctuations in feed
supplies with constant requirements include the promotion of
packages which combine various feed resources such as forage
legumes, fodder trees, cottonseed cake and agro- industrial by
products to supplement grazing and to provide adequate feed
supplies throughout the year.
In mixed farming systems where crop production and animal
husbandry are closely integrated, the availability of
cottonseed cake, especially during and after harvest, provide
cheap sources of feed for livestock. In Mali, the use of
cottonseed cake as livestock feed has long been encouraged in
the semi -arid and subhumid zones. In 1975, the ECIBEV
(Etabl issement de Credit et d' Invest issement Betai l-Viande) was
established with financial assistance from USAID (United States
Agency for International Development) to provide credit to
peasant farmers to undertake on-farm cattle feeding in the dry
season.
"Embouche Paysanne", the smallholder cattle-feeding
project in the semi -arid zone of Mali started with 48 peasants
involving 107 animals in 1975 and had grown to 1105 peasants
and some 3600 animals by the end of 1986. Under the programme,
peasants obtained credit for the purchase of mature feeder
cattle and supplementary assistance in the form of concentrates
and veterinary care from ECIBEV. Animals were then fed on-farm
on cottonseed cake and agro- industrial by-products for about
three months in the dry season and sold in May when prices
normally reached their peak. This paper presents the economic
50
aspects of the feeding project based on observations from 1984
to 1986 within a sample, on average, of 31 farmers.
The study area
The cattle feeding activities were monitored in the Banamba
zone of Mali, located west of the Niger river and about 150 km
north of Bamako. The zone lies within isohytes of 600 and 800
mm of annual rainfall but has received less than 600 mm in
recent years. Between 1975 and 1985 for example, it received an
average of about 579 mm, with 1983/84 being particularly dry.
In general, the zone experiences a short rainy season between
June and September during which about 85% of the total annual
rainfall is received. This is followed by a long dry period
from October to May. The zone is characterised by mixed crop-
livestock production systems. The principal crops grown are
millet, sorghum, cowpeas and groundnuts. The average household
keeps cattle, sheep and goats, as well as donkeys and some
poultry. Producers in the study area have access to three major
weekly markets which serve as the main centres of trade for
agricultural and livestock products.
The sample
A general criterion for credit and participation in the feeding
programme is the ownership of work oxen and/or agricultural
equipment. This fulfils the function of a guarantee of credit
worthiness, and in the case of work oxen, an indication that
the farmer has had previous livestock management experience.
Approximately between 29 and 33 participating farmers and
a total of about 125 feeder cattle were observed from 1984 to
1986. Roughly 50% of the farmers fed four or more animals over
the study period. In terms of land ownership, the sample
owned on average 9.8 ha of crop land per household. They also
possessed livestock holdings of 11.5 cattle (including at least
1 ox), 9 sheep and 16 goats, on average, per household. A
participating household comprised, on average, 16 members of
which approximately 10 were active members of the family labour
force.
51
The animals involved in the fattening programme were
generally Peul and Maure Zebu bulls and steers, 7 years of age
or older, of which the majority were castrates. In 1986 for
example, 58% of the animals were Peuls and 39% Maures. Eighty-
one percent were castrates, 11% entire males and 8% females.
The principal components of the daily ration consisted of
millet and sorghum stalks (17%), bush hay (35%), and cottonseed
cake supplements (40-60%). These components together
constituted between 84% and 97% of total daily feed intakes.
The cattle entering the fattening programme were given
routine vaccinations for rinderpest and contagious bovine
pleuropneumonia, anthelmintic treatments and prophylactic
treatments against trypanosomiasis. A mortality rate of less
than 3% was observed during the fattening period.
Purchase of feeder cattle
The procurement of feeder cattle was made possible by a fixed
credit in the amount of 45000 CFA per animal. In the Banamba
area, the farmers had to supplement the credit from their own
resources as average prices usually exceeded the amount of
credit. Prior to purchase, the farmers made several trips to
livestock markets in the area to ascertain price levels and the
general conditions of the animals. Although cattle were not
explicitly sold by weight in the local markets, the study
showed a strong relationship between actual liveweights of the
animals being sold and their total sale prices. Cattle buyers
thus bought by estimated liveweights for a reasonably constant
price per kilogram. Estimated purchase prices for Maure Zebus
averaged 161 CFA and 230 CFA/kg in 1985 and 1986 respectively.
Corresponding figures for the Peul Zebus in 1985 and 1986 were
171 and 219 CFA/kg respectively. The average weights of all
cattle entering the programme were 339 kg in 1985 and 304 kg in
1986.
Sale of fed cattle
The average weights of finished animals were 370 kg and 356 kg
in 1985 and 1986 respectively. They were normally sold by the
52
farmers themselves at home or in nearby local markets. The main
buyers were cattle dealers who generally bought for terminal
markets in the capital, Bamako, and other urban markets such as
Kati. Informal purchase contract arrangements were usually made
between buyers and the farmers prior to the end of the the
feeding period. Animals sold this way were sold on credit of
about 30 days duration. The Maure Zebus were sold at estimated
unit values of 208 CFA and 288 CFA/kg in 1985 and 1986
respectively while the Peuls were sold at 228 and 302 CFA/kg
respectively. Table 1 summarises the purchase and sale weights
and prices for the two types of cattle in 1985 and 1986.
Table 1. Purchase and sales summary of Maure and Peul Zebus in
the feeding programme.
Cattle type Maure Peul
Year 1985 1986 1985 1986
Average purchase weight (kg) 356 308 329 302
Average purchase price (CFA) 57316 70840 56259 66138
Average purchase price per kg (CFA) 161 230 171 219
Average sale weight (kg) 400 360 345 351
Average sale price (CFA) 83200 103680 78660 106002
Average sale price per kg (CFA) 208 288 228 302
ECONOMIC ANALYSIS
The economic analysis of the smallholder cattle feeding
programme reported here involves the examination of overall
profitability, the determinants of profitability and possible
measures for improving the economic performance of
participating farmers.
53
Financial and economic viability
The gross financial margin, defined as the difference between
the final sale price of a fed animal and its initial purchase
price, was 25320 CFA per animal in 1985 and 35319 CFA in 1986.
Because this margin excludes feeding costs as well as other
cash and opportunity costs of labour and farmer-produced feed
during the feeding period, it represents an overestimate of
profitability. However, by subtracting direct cash costs for
feeding and labour from the gross financial margin,
profitability was expressed in terms of the net financial
margin per animal. These were 3391 CFA and 4748 CFA in 1985 and
1986 respectively. The net financial margins were then
expressed as percentages of total financial costs and
multiplied by the fraction of the year animal was fattened to
obtain annual financial rates of return of 63% in 1985 and 687
in 1986. Taking further account of the opportunity costs of
family labour and of farmer-produced feed, the resulting
economic rates of return to fattening were O% and 21% on
average in 1985 and 1986 respectively. Although on average
farmers appeared to get high returns to fattening, as much as
27% of the sample for example in 1985 made no profit or
actually lost money in cattle feeding. Table 2 shows the
distribution of financial and economic returns within the
sample population in 1985 and 1986. In 1985, about 61% of the
sample made net financial returns of over 10000 CFA per animal,
compared with 29% in 1986. Similarly in 1985, 86% of the sample
made economic returns of less than 10000 CFA per animal
compared with 50% in 1986.
Disaggregation of the gross margin
In order to examine the relative contributions of weight gains
and of price changes to the gross margin during the course of
the fattening, period the gross financial margin was
disaggregated as follows: Let C = cost of purchasing cattle, R
■ revenue from selling cattle, P = price per kg of liveweight,
W = liveweight in kg, and d = change in P or W over the
54
fattening period. For the subscripts, let i = initial period
representing the beginning of fattening and f = final period or
the end of fattening. Then,
(1)
(2)
(3)
C = pi * Wi
R = Pf
R
*Wf
- C
By definition,
Pf = Pi + d(P)
and Wf " Wi + d(W)
(4)
<5)
Substituting equations 4 and 5 for R in 2 and expanding, we
have
M * d(P) * W. + d(W) * P. + d(P) * d(W) <6)
Dividing equation 6 by M and multiplying by 100% gives
100% = <%(d(P)*W.) + X(d(W)*P.) + %(d(P)*d(W))>/M (7)
The first term on the right-hand side defines the price
component of the gross margin and is the change in price
multiplied by the original weight, the weight component is the
second term and is equal to the change in weight multiplied by
the original price, and the interaction component is the
change in price multiplied by the change in weight. All the
components are expressed as percentages of the gross financial
margin. In 1985, the weight gain for the sample as a whole
accounted for 27% of the gross margin while price changes and
the interactions accounted for 67% and 6% respectively.
Corresponding figures in 1986 were 45%, 46X and 9%
respectively.
Perspectives for improving performance
In the last two years of the feeding campaign, the price
component averaged 55% of the gross margin as compared with 37%
for weight gains. This suggests that price changes over the
feeding period played a relatively important role in the
determination of profitability. A regression analysis of the
55
determinants of unit sale prices indicated that liveweight,
number of days fed, duration of credit and seller type (i.e.
whether seller is ECIBEV-sanct ioned seller or not),
significantly explained variations in unit sale prices at the
5% level. These factors together accounted for 52% of the total
variation. Liveweight and number of days fattened had negative
coefficients suggesting that the fatter animals were allowed to
get and the longer the feeding period, the lower the unit
prices received. The duration of credit and seller type had
positive influences, indicating that ECIBEV-sanctioned buyers
received higher unit prices, and those who gave longer periods
of credit obtained higher prices.
Table 2. Distribution of financial and economic benefits
within the sample.
Net financia I benefit Economic benefit
1984/85 1985/86 1984/85 1985/86
C FA/ animal n % n X n % n X
0 < = 0 8 26 13 46 12 57 4 22
1 - 10000 4 13 7 25 6 29 5 28
10001 - 20000 18 58 6 22 3 14 5 28
> 20000 1 3 2 7 0 0 4 22
Source: Baur and Sissoko (1986).
Apart from the purchase of feeder cattle which represented
about 70% of total production cost, feeding was the most
expensive item ranging from about 22% to 29%. One way farmers
might increase profitability is by reducing feeding cost per
animal by perhaps reducing the amount of cottonseed cake in the
ration since it represented 41% and 53% of total feed costs in
1985 and 1986 respectively. A number of feeding trials were
conducted in 1986 in order to determine the economic viability
of the programme using reduced amounts of cottonseed cake or
partly replacing it with farmer-produced cottonseed cake. It
involved 6 rations conducted over 36 animals for 77 days. The
rations were:
56
1. Bush hay (ad lib) + 2 kg cottonseed cake <T1)
2. Bush hay (ad lib) + 4 kg cottonseed cake (T2)
3. Bush hay + 40% molasses ♦ urea + 2 kg cottonseed cake (T3)
4. Bush hay + 40% molasses + urea + 4 kg cottonseed cake (T4)
5. Bush hay + 2 kg cowpea haulm + 2 kg cottonseed cake (T5)
6. Bush hay + 4 kg cowpea haulm + 4 kg cottonseed cake (T6)
The effects of these rations on average daily weight
gains are shown in Table 3. In general, animals fed on 4 kg
cottonseed cake gained more weight than those on 2 kg per
day. The addition of molasses and urea to bush hay and
cottonseed cake resulted in higher weight gains than the
addition of cowpea haulms.
Table 3. The effects of diet on average daily gains.
Weight gain (kg/day) when
fed cottonseed cake
Bush hay (ad libitum) 2 kg/day 4 kg/day
Bush hay (T1 , T2) 0.72 1.01
Bush hay + molasses/urea (T3, T4) 1.00 1.12
Bush hay + 2 kg cowpea haulm
(T5, T6) 0.85 1.04
_m
T1 - T6 are rations.
An economic analysis was carried out on the rations using
1985 prices. The results are shown in Table 4. Rations T2 and
T1 were the most profitable followed by T3, T4, T5 and T6 in
that order. Rations T5 and T6 which replaced molasses and urea
in T3 and T4 with farmer-produced cowpea haulms were less
profitable, since the opportunity cost of cowpea haulms appear
to be higher than the market prices of molasses and urea. A 50%
increase in the cost of cottonseed cake was hypothesised and
the profitability of the rations re-examined. Although the
order of profitability did not change much, ration T1 with
lower amounts of cottonseed cake became more profitable than
T2.
57
Table 4. Profitability of alternative rations in the cattle
feeding programme.
T1
Rations
T2 T3 T4 T5 T6
Average initial wt (kg)
Average final wt (kg)
Average weight gain (kg)
Gross returns (CFA)
Total ration cost for 77
days (CFA)
Net returns (CFA)
Effect of a 50% increase
in the cost of cottonseed
cake: Net returns (CFA) 22411
266 266 266 266 266 266
321 344 343 352 331 346
55 78 77 86 65 80
38055 45070 44746 47510 41105 45680
12243 18172 21637 25564 20790 26026
25812 26898 23128 21946 20315 19654
20323 19727 15865 16666 12967
Source: Baur and Sissoko (1986).
CONCLUSION AND IMPLICATIONS
Smallholder beef fattening, especially in the dry season, is a
way by which agropastoral ists can intensify the traditional
system and increase farm income. The majority of the sample
farmers in the feeding project made money during the dry season
to augment their farm income. The gross margin analysis shows
that substantial portions of the margin is made up of gains due
to price speculations. One implication of the importance of
seasonal price fluctuations in the livestock market is that
farmers can strategically raise their animals towards target
markets such as dry season markets and religious festivals to
take advantage of high prices.
The small negative but statistically significant
relationships between unit sale prices and liveweight gains as
well as length of feeding period, implies that since sales are
58
made on weight estimates rather than actual weights, it may not
be advantageous to get the animals too fat or keep them on feed
for too long.
Finally, the results of the feeding trials appear to
indicate that the profitability of a ration depends on the
relative prices of the components and the final products. For
example since the opportunity costs of cowpea haulms at the
time of the trial were higher than the market prices of urea
and molasses, rations that contained cowpea haulms, designed to
replace the industrially produced urea and molasses were less
profitable. In 1985 the price of cowpeas in the market was
exceptionally high as a result of the particularly dry 1984/85
cropping season. In normal years one would expect the
opportunity costs of feeding farmer-produced cowpea haulms to
be lower than the price of industrially produced feeds and
therefore quite profitable to smallholder cattle feeders.
The current feeding performance of cattle in the programme
depends very much on the availability and af fordabi I ity of
cottonseed cake. Even if prices are currently within reach,
the profitability of feeding cottonseed cake will eventually
drive up its demand hence its cost to farmers. The effects of
anticipated increases in its price (a hypothetical 50%
increase), clearly indicates that rations with reduced
quantities, even though they produce smaller daily weight
gains, are more profitable to feeders. The implication is that
if farmers could obtain cottonseed cake at lower prices and
hence use greater quantities, they would be able to turn out
heavier animals over shorter feeding periods. However, since
the unit cost of a commercially produced feed on the farmer's
field includes transportation costs, feeding animals close to
feeds factories where transportation costs are minimal appears
to be a good strategy for increasing profitability.
ACKNOWLEDGEMENTS
The co-operation of the sample members and the help of the
Project Sectoriel team are greatly appreciated.
59
REFERENCES
Baur, H. and Sissoko, K. 1986. Aspects economiques de
I'embouche paysanne de bovins: Synthese des resultats de
rechereche en zone semi-aride du Mali (1984-1986).
Presente aux Commissions Techniques Specialises des
Productions AnimaIes, Session de Juin 1987.
60
Combinations of agro- industrial by-products for use in dairy
diets formulated by on-farm use of a least cost ration system
J.N. Chesworth1, D.F McKillop1 and D.J. Spriggs2
University of Zimbabwe, Department of Animal Science
P.O. Box 167, Mount Pleasant, Harare, Zimbabwe
2National Association of Dairy Farmers
P.O. Box 1241, Harare, Zimbabwe
ABSTRACT
The main limitations to the use of by-products in diets for
farm animals are the uncertainty of the likely response in
terms of animal production and their need for supplemenat ion
with other materials to provide a diet adequate for the needs
of production. These problems are found at all levels of animal
production from subsistence systems to commercial farming. In
industrialised countries and some developing ones agro-
industrial by-products are commonly incorporated into
commercially compounded feeds on a basis of decisions made
using computing methods. A computer package has been written to
offer these same facilities at a relatively low-cost to the
individual or group of farmers. The system has application in
situations in which there exists some element of choice in the
feeding of animals. There are three components to the system
for calculating diets in this way.
This paper describes the development and application of
one such system as a decision-making tool in the optimisation
of utilisation of feeds, including agro- industrial by-products,
on dairy farms in Zimbabwe. Copies of the computer package are
available to organisations in developing countries for the cost
of the media.
INTRODUCTION
Application of feeding systems in small-scale agriculture
At the previous meeting of the African Research Network for
Agricultural by-products held in Egypt, strong criticism was
61
voiced of the application to small-scale farming operations of
feeding standards, developed in industrialised countries
(Preston, 1986). This criticism was based upon the fact that in
some subsistence-type farming environments it has been shown
that animal performance obtained after the feeding of
combinations of poor quality materials was not accurately
predicted from published laboratory assessments of these feeds.
If it is accepted that at very low levels of production it
is inappropriate to use feeding systems but that it is entirely
correct when dealing with animals on large-scale commercial
enterprises then there must be a point of cross-over between
the two. Most of the difficulties with the application of
feeding standards stem from the fact that many of the forages
and by-products that are used in subsistence agriculture are of
relatively poor quality and that book values for their probable
nitrate composition give a poor prediction of their usefulness.
The reason for this is to be found in the so-called associative
effects of feeds. These are often ignored in the formulation of
rations in large-scale farming as, with high quality diets,
they bring very limited changes. As the number of ingredients
in a diet is reduced the chances of large interactive effects
increase.
Given a very large number of dietary components there is a
much greater chance that the range of materials will combine to
i) support optimum rumen fermentation and ii) supply materials
to the rumen hall and to the hind gut in approximately the
right proportions. One of the objectives of feeding systems
such as the combined ME and new protein systems of the ARC
(1980, 1984) has been to give results which will provide good
rumen fermentation leading to the uptake of appropriate
materials from the gut. That it is not possible to transfer
such rationing systems to many small-holder situations is due
to the fact that the small number of materials of very
unbalanced composition which are available do not combine
satisfactorily to provide optimum rumen fermentation.
62
The dairy industry in Zimbabwe
Zimbabwe has a very well developed commercial dairy industry
which is characterised by a relatively small number
(approximately 540) of large-scale producers. The technology
used on many of these farms is comparable to that found in
industrialised countries; in addition cows are of European
breeds and are usually fed on combinations of home-grown
roughages together with factory-compounded concentrate feeds.
Since Independence there has been a move towards the
development of a small-scale dairy sector. The objectives here
are twofold: (i) to provide a higher level of nutrition for the
human population in these areas and (ii) to create some cash
income for small-scale farmers. As a consequence of the large-
scale commercial industry the country already possesses a
sophisticated distribution and marketing network serving a
largely urban market. Much of the infrastructure in terms of
bulk-handling facilities is already in place and in a number of
areas points have been established for the collection of milk
from small-scale producers.
The fact that the infrastructure exists for the farmers to
get their produce to the market also means that they are able
to buy foodstuffs from external suppliers and do not have to
rely solely upon farm-produced materials. The largest schemes
of this nature form part of planned resettlement schemes where
the farmers would have access to land, water and amenities such
as schooling. Many farming decisions are not available to the
farmer; he is only allowed to crop a part of his land, the
remainder must be used for animal production. As a part of the
whole package, they are growing Napier grass, Pennisetum
purpureum (approximately 2.23 ha per producer), and have a
smaller area for cropping. Under Zimbabwean conditions Napier
grass may be expected to yield between 4 and 10 tonnes of dry
matter per hectare per year (Addison, 1952). Under most
conditions this dry matter has a relatively low crude protein
level. Cropping will undoubtedly produce residues which may
also be incorporated into the animal production systems. Again
these materials may be expected to be of low digestibility and
low protein content. In addition to the home-produced feeds
63
they are purchasing compounded feeds from stock-feed companies
and thus are in the same market as their large-scale
colleagues. Farmers on the resettlement schemes have costs to
meet in producing their milk and in transporting it to the
collection points and for this reason they have to work on
similar, but smaller, budgetary considerations.
One of the factors which has underlined government policy
towards the dairy industry over the past few years has been a
notable squeezing of the margins between the permitted prices
of compounded feeds and the producer price for milk. The same
prices are paid to all producers irrespective of size of
enterprise so the difficulties are common to all sizes of
farms. These changes in financial structure have resulted, in
the commercial sector, in a much greater interest in the home-
mixing of feeds and the incorporation into them of cheaper
materials, many of them agro- industrial by-products. The aim is
to balance what materials the farmer has with the minimum
amount of purchased food. On the small-scale resettlement
schemes the aim is just the same. These organised small-scale
schemes do have one advantage over the more scattered
communities which are typical of subsistence farmers: they are
concentrated in one place and can use this opportunity to
purchase larger quantities of feed or feed ingredients.
Availability of agro- industrial by-products in Zimbabwe
A large number of the ingredients available to the feed
formulator are in fact agro- industrial by-products as these are
generally cheaper than products which are available to the
human food market. Within Zimbabwe many of the milling by
products are not accessible in raw form to the farmer as they
are used by the feedstuffs divisions of the milling companies
which produce them. A list of some of the by-products currently
available in Zimbabwe is presented as Table 1.
Availability of computing facilities
Computers are now increasingly available to farmers and
extension workers for a whole variety of tasks. The cost of a
64
machine of sufficient sophistication for the formulation of
livestock diets has fallen dramatically in recent years. In the
early years of the decade one would have cost about the same as
an expensive limousine, now when freely available they are
about the same price as a basic motor cycle.
In addition to the computer hardware the following
components are needed:
1. a system for calculating the likely requirements of farm
animals,
2. a knowledge of the nutritional properties of each material
which is likely to be fed expressed in the same terms as
those in which animal requirements have been described, and
3. some way of choosing, from the information on feeds, the
most advantageous mixture needed to satisfy the needs of
animals.
Animal requirements
In designing a rationing system for farm animals the first
consideration has to be the method used for the expression of
animal requirements. There are a number of competing methods
which have been developed in different countries of the world.
In setting up the original computer program one consideration
was to look for a system which would generate easily the values
for the requirements of each nutrient. It was for this reason
that we chose the British ARC method (ARC, 1980, 1984).
There are some disadvantages to the British scheme, the
first one being the need to establish the quality of the diet
before calculating the animal's needs and thus before the diet
can be formulated. The technique has therefore to be an
iterative one starting from a 'good guess' based on a
knowledge of the materials likely to be available. The second
is in the use of the protein rationing system. The theoretical
basis of the ARC protein system (ARC, 1984) is not in serious
question, it provides a useful conceptual framework which
65
explains many of the apparent anomalies in previous schemes.
Where it breaks down is in its need for an estimate of the
likely fate in the rumen of any one protein source. Basically,
the degradation of proteins will depend on the fermentative
environment of the rumen and on the rate at which materials
pass through. These will in turn depend upon the particular
combination of feeds which enter the rumen, in other words it
is necessary to know the result of the dietary formulation
before starting to devise it.
Table 1. Agro- industrial by-products available directly to
farmers in Zimbabwe.
Grain products Straws and stovers
Maize superdust
Cracked maize
Sorghum bran (red and white)
(Note: wheat products are not
generally available to
the farmer directly)
Animal by-products
Feather meal
Poultry manure
Meat and bone meal
Blood meal
Fish waste
Maize stover
Sorghum stover
Wheat straw
Barley straw
Navy been straw
Soyabean straw
Cotton stalks
Oi I seed and associated products
Cottonseed meal (extracted)
Cottonseed (whole)
Cotton hul Is
Sunflower meal
Sunflower hulls
Soyabean meal
Groundnut hulls
Human food and beverage by
products
Bakery waste
Peanut skins
Brewers grains
Navy (baked) bean waste
Fruit pulp
Grape residues
66
In evolving a practical scheme that could be used some
ways around these had to be found. In relation to the dietary
quality, a first approximation of a metabolisabi lity (q) of 0.5
is taken. This represents an overall ME in the dry-matter of a
little less than 10 and is probably fairly representative of
the overall diets that may be offered to dairy animals in
tropical environments. At the end of the formulation procedure
the metabol isabi I i ty of the diet is estimated by the program
and if this value differs widely from the starting estimate the
operator is warned to start the whole procedure again using the
new value.
Estimates of protein requirements made using the British
system depend upon two completely separate sets of figures.
The first is an estimate of the likely needs of the animal for
amino acids. These figures can be well predicted from
physiological data. The second set of information concerns the
ability of the feed to provide amino acids. Here the precision
of estimates must be much lower. The main problem is that many
of the by-products which we might like to use have not yet been
investigated.
When the ARC protein system was first published it was
suggested that feeds should be divided up into four groups
depending upon their likely degradabi I ities, each being
assigned an assumed value. We have continued this procedure by
ascribing new materials to the most similar group. To give some
sort of latitude to the formulation in terms of protein quality
we calculate independently the protein (UDP) and the rumen
degradable protein (RDP) and sum them to produce the overall
crude protein <CP> figure. A quite arbitrary 'safety margin' of
10% is added to the overall crude protein figure. In setting up
the requirements for linear programming all three, UDP, RDP and
CP are made 'greater-than' constraints. This means that an
oversupply of protein is given but that this can be made up of
either RDP or UDP.
There are two constraints which are set by the program
package which are not derived from the ARC (1980, 1984)
67
recommendations. These are for the minimum value of fibre in
the diet and for the maximum value of fat. Neither of these is
likely to be a significant problem for the small-scale
producer. Given his inputs of poor quality crop residues or of
very fibrous grass then he is unlikely to be short of fibre.
Similarly it is unlikely that he will have access to high fat
materials such as unextracted soyabeans.
It was decided not to formulate in terms of trace
elements; it is notoriously difficult to predict reliably the
trace element composition of feeds particularly when buying
feed ingredients from distant, and possibly unknown, sources.
As a policy we recommend the incorporation of the recommended
amount of a proprietory mineral mixture in what has been
referred to as the "shot-gun" approach. This has the added
advantage of reducing the number of constraints that may be
applied and thus speeds solution of the linear programming
matrix. The constraints applied to formulation are shown in
Table 2.
Table 2. Constraints used in dietary formulation.
Component Unit
Metabolizable energy
Crude protein
Rumen-degradable protein
Undegradable protein
Calcium
Phosphorous
Magnesium
Fibre
Fat+
MJ/kg dry matter
g/kg dry matter
*Set to be 10% higher than the sum of rumen-degradable and
undegradable proteins.
-•-Set as a maximum value.
68
Information of feed composition
To perform the calculation, figures are needed for the
composition of each of the individual ingredients that may be
considered for inclusion in the diet. In a large commercial
organisation there may be several hundred ingredients that are
available to the compounder. It is not possible for the
company to analyse every batch of material as it enters the
factory and indeed this may be a waste of time in terms of the
known variability of sample composition between different parts
of the same bulk delivery of a feed. Not only this, the feed
manufacturer may not physically have some of the ingredients on
his premises at the time at which the initial formulation is
undertaken. Buying of a needed ingredient may actually follow
the decision to incorporate it. The feed manufacturer thus
makes his decisions on the incorporation of ingredients on a
basis of information which he has gleaned from a wide variety
of sources and which experience has shown him to be relatively
reliable. As an example of the consistency of data relating to
feed composition it is worthwhile looking at the detailed
studies of the Rowett Research Institute's Feed Evaluation Unit
(FEU, 1980). For example, 16 samples of maize from all over the
world had ME values with a mean of 13.7 MJ/kg dry weight and
coefficient of variation of only 6.6%; the average crude
protein was 104.5 g/kg dry weight with a coefficient of
variation of 5.0%. It is unlikely that changing the maize from
the best one to the worst would have had any great effect on
the cost of diets which incorporated them, nor upon the
resulting animal production.
In setting up the linear programming system for use on
farms a major difficulty has been in ascribing likely nutrient
composition to many of the materials which have been found to
be available in relatively small amounts. The collection of
data has used a large number of sources and not all of these
are consistent in the ways in which they calculate or even
express their information. In a small country it is not
possible to have analytical data on every single type of
material, much less every batch that is released onto the
69
farming market. Many of the materials which do become available
are common to a number of countries and it ought to be possible
to agree on one or two 'compromise' figures that describe the
properties of each type of feed. Such effort would be more
economically expended at an international level and as such
would tend to reduce the problems associated with the various
schemes of analysis employed in different countries.
The use of analytical figures which may not precisely
reflect the nutrient value of the material under consideration
is open to question. If, however, we look for instance at the
metabol i sable energy of a poor quality feed and consider it for
incorporation into a diet, does it matter significantly if we
assume its ME to be 8.5 rather than 7.5 MJ/Kg, the errors that
we shall experience in arriving at first estimate of intake may
be much greater than this. It must be emphasised that this is a
management tool and only provides a likely first estimate that
the farmer will have to modify in the light of experience.
Linking of the animal requirements and feed composition
The programs have been written to run on two different
machines. The first release (Release 1.0) of the package was
written for the small farm which might have access to a 'BBC
Model B' computer manufactured in Britain by the Acorn
Computers Limited (Cambridge, England).
With the rapid increase in the number of computers
available in the agricultural sector in Zimbabwe it became
obvious that the main type of machine that was and would
continue to be available was the IBM personal computer (IBM/PC)
and its derivatives and copies. With this in mind a second
version of the program was written. The flexibility of the
system was reduced by fixing the number of constraints to 9 and
by limiting it to cattle diets. With the larger amounts of
memory available on the IBM/PC machines it became possible to
increase to a maximum of 30 the number of ingredients
considered each time a diet is formulated.
70
Operation of the package
Animal requirements
The package consists of three elements. The first section
calculates, according to the ARC (1980, 1984) recommendations,
the likely daily nutrient requirements of cattle under
different production systems for ME, crude protein, rumen-
degradable protein, undegradable protein, calcium, phosphorous
and magnesium. The user is then prompted to enter values which
he considers appropriate for the maximum amount of fat and the
minimum amount of fibre in the ration (there are default values
of 50 and 150 g/kg dry matter respectively). The program also
calculates a maximum value for the dry-matter intake of the
animals using relationships that are described elsewhere in
this paper. These relationships are ones which have been
developed for the most part using cattle of European breeds and
maintained under good nutritional conditions. The estimates may
not be appropriate for all conditions so provision is made for
the estimates to be reduced in the light of experience with
local conditions. Once the nutritional conditions have been
set, the display shows the likely nutrient densities (in MJ/Kg
or g/kg dry-matter as appropriate). If any of these figures are
apparently out of line with practical diets the figure is
'starred' and the user asked to consider collecting the dietary
requirements again with more realistic production targets. As
an example, it is unlikely that diets with an ME content of
more than about 13.5 MJ/kg could be formulated under practical
condition. Once the operator is satisfied with the ration in
terms of its composition the details are sorted as a data file
until required for the third segment of the package.
Feed information
The second element of the package is a data handling system for
the feedstuff s which works similarly to a standard spreadsheet.
This program can create and maintain a file in which details
are kept of all the ingredients which are likely to be
encountered in the country in question. The maximum number of
ingredients that may be so maintained at the moment is 98 but
71
there is no reason why this number should not be increased if
users find the current limit too restrictive. The filing system
works rather like a commercial menu-driven spreadsheet. In
addition to the nutritional data on any material the price per
kg of fresh weight must be entered. The individual user in his
own country will have to build up this file for his own
circumstances. There is on the diskette as released a trial
version of the data file but this is included only for
demonstration purposes and no guarantee is given as to the
accuracy or applicability of the data.
Not all of the ingredients which are stored in the main
matrix file will be available to the user at any one time. For
this reason when making practical diets the user chooses a
subset of ingredients that he already has or to which he might
have access. The maximum number that can be chosen for
consideration on entry into the diet is 30. On a farm, a co
operative or in a small feed manufacturing company it is
unlikely that this figure will need to be exceeded.
Restrictions on inclusion
At this stage the user may choose to set limits on the
inclusion of materials into the ration. For instance, in the
case of a roughage of low quality it is often prudent to set a
maximum amount to the proportion of the overall diet that this
can represent due to the fact that it is likely that the animal
will have a very restricted voluntary intake of this material.
On the other hand, if the farmer has a very large stock of some
material, it may be that he has to include at least some of it
in his diets to ensure that it does not go to waste. The
inclusion of this ingredient will have to be limited in the
opposite direction, in other words the user sets a minimum
amount that must be incorporated in the diet. It has to be
admitted that limits of this nature can often prove to be
obstacles to the successful formulation of diets and the tool
must be used with great care. One other way of promoting the
inclusion of an ingredient into a diet is to reduce its price
to a ridiculous value and see if the least cost formulation
includes or excludes it. If the ingredient is excluded even at
72
a very low price it may be that the prudent farmer will
consider throwing it away as its use is likely to cost rather
than save money.
Dry-matter intakes of roughages
It is a fairly clear limitation to the use of roughages of low
digestibility that it is difficult to assess the likely intake
of such materials by ruminants. Intakes of some of the poorer
materials may be as low as 0.5% of body mass whereas intakes as
high as 1.8% of body mass have been achieved by animals given
improved roughages supplemented with sources of high quality
concentrates. Obviously in designing diets for livestock the
likely intake has to be a major consideration.
In assessing dry-matter intakes of dairy animals we have
used models that have been developed and used with great
success in industrialised countries. A selection of such
regressions is presented in Table 3.
Table 3. Equations used for prediction of total dry-matter
intake of cows.
A. TDMI1 = 0.10MY + 0.015LW
B. TDMI2 = 0.2MY + 0.22LW
C. TDMI3 = 0.076 +0.404CDM+0.013LW-0.129WL+4.120log WL+0.KMY
D. TDMI = 3.476 +0.404CDM+0.013LW-0. 129WL+4. 120log WL+0.14MY
E. TDMI4 = 27.8 + 106. 5q x LW°'75/1000
F. TDMI5 = 116.8 - 46. 6x x LW°"75/1000
Where TDMI is total daily dry-matter intake, CDM is concentrate
dry-matter intake/day, MY is daily milk yield in kg/day, WL is
week of lactation, LW is animal liveweight in kg, q = diets of
0.5, 0.6 and 0.7 kg/d of DMI.
Notes :
73
1,2. For cows on Iow and medium quality diets equations A and B
are used, the latter for high yielding cows (defined as a
daily milk yield of over 15 kg/day)
3. For lactation cows receiving high quality diets (defined
as those with an overall metabol isabi I i ty of 0.65 and
above) equation D is used, the quantity of concentrates
being calculated on a sliding scale assuming a
metabol isabi I ity of 0.55 for the roughage component and
0.7 for the concentrates.
4,5. The program selects equations E and F for non- lactating
cows receiving coarse and fine roughages respectively.
For the origins of equations A-D see Caird and Holmes (1986).
Equations E and F are from ARC (1980).
Preliminary results obtained recently in Zimbabwe in a
large scale trial in which a variety of treated roughages were
fed to growing heifers on dairy farms are shown in Table 4. In
each of these trials the animals were fed a high quality
concentrate mixture of maize, cottonseed and soyabean meals and
minerals at the rate of approximately 1% of live body mass. It
can be seen from these figures that dry-matter intakes ranged
from about 1.4 to 1.8% of live body mass. Most of these
materials were of fairly high quality prior to chemical
treatment and thus effects of treatment are not as great as
might be expected. On the basis of these figures and those to
be found in the literature we have made the assumption that
roughage comes in 4 categories: poor, mediocre, good or
excellent. The likely intakes of these materials as dry-matter
have been set at 0.8, 1.0, 1.4 and 1.8% of live body mass. When
setting the restrictions upon the inclusion of materials in the
rations the appropriate figure is entered as a maximum value
for the chosen roughage. This is likely to be subject to
enormous errors but it has to be remembered that the whole
purpose of the package is not to provide a precise prophesy
of the amount of each dietary constituent to be consumed, it is
a management tool to assist in decision making.
74
Linear program
The third segment of the program consists of the linear
programming itself. The program calls for the name of the file
on which details of the ingredients have been stored and the
file on which the diet is specified. The user can then look at
the matrix of data which is to be used to formulate his diet.
It is also possible for data to be edited at this stage, for
instance the user can change the specification of the feed to
see what effect this has on the composition of the diet or even
on its feasibility. After the user has finalised his choice of
values the program continues to calculate the least cost
ration. The results are expressed in terms of dry-matter and
fresh matter.
Experience in the use of the programs
The suite of programs was originally written with the small
farm in mind. It has been tested over a period of two years on
a group of small- to medium-sized dairy farms in the Chequtu-
Kadoma area of Zimbabwe through the co-operation of the
National Association of Dairy Farming in Zimbabwe. Much of this
area has a mean annual rainfall of approximately 650-800 mm and
some is in natural region III. Some of the farms have limited
areas of irrigation but many are involved in dry- land farming.
It was found that most of the dairy farmers in the area were
purchasing their feeds from one of four very large commercial
compounders. The initial part of the study involved taking the
manufacturers' published specification of feeds and formulating
similar products. The saving to the farmer of home-mixing of
feeds as against the cost of purchasing a ready made product
varied from 15 to 45% depending on the feed. In general,
savings were greatest with those feeds which had lower nutrient
densities.
75
Table 4. Intakes of treated roughages by heifers (Holstein and
Friesian breeds) on dairy farms in Zimbabwe.
Site
Ruua
Roughage source
Maize stover
Treatment intake
Chopped 1.6
Chopped, urea added
at feeding 1.6
Urea incubated 1.8
NaOH (4%) 1.8
Nyamandhlovu Chopped 1.8
Chopped, urea added
at feeding 1.8
Urea incubated 1.8
NaOH (4%) 1.8
Norton Wheat straw None 1.3
ii ii n Urea added at
feeding 1.4
it ii ii Urea incubated 1.4
ii ii n NaOH (4%) 1.5
Chegutu Veld hay Chopped 1.6
Chopped, urea added
at feeding 1.5
Urea incubated 1.8
NaOH (4%) 1.8
Dry-matter intakes are expressed as percentage of livemass,
mean values for pen of ten animals per treatment (figures
rounded to one decimal point). Preliminary results of
Chesworth, Smith and Spriggs.
The stover used in this trial was from green maize
production and was exceedingly 'sweet'.
The next stage was to use the programs as a tool in the
determination of the overall policy of the farm. Farmers were
76
encouraged to list the quantities of materials that they
expected to have available on their farms. These materials,
principally low digestibility products such as veld grasses and
crop residues such as maize stover and soyabean hay, were then
forced into formulation both passively by setting their prices
down to exceptionally low levels (typically the direct material
costs of harvesting them) and by setting their levels as
constraints in the formulation. Overall diets formulated in
this way included roughage materials which were not normally
mixed and included in a complete diet. Animals were allowed
access ad libitum to the roughage and the higher quality
materials were fed as a mixed meal in line with the normal
feeding policy on that farm. For this reason the formulation
program has the facility to give the composition of the
required diet after the subtraction of one (release 1.0) or
more (release 2.0) ingredients. The use of the program led to
much more complete utilization of the materials available on
the farm.
Future developments
Linear programming as it is used in most of the feed industry
is a method which has only one clear-cut objective: it chooses
the unique combination of ingredient materials which are the
cheapest way of satisfying a series of fixed criteria. The feed
industry does not have any duty to look further than that. The
objectives of the farmer may be much more complex than those of
the manufacturer. He has a number of criteria which are poorly
defined and about which he has to make decisions. The decisions
are made on the basis of imperfect data and are not all equal
in their importance to him. As a simple example of this,
compare the meeting of criteria for metabolisable energy with
those for calcium. To increase the ME of a feed from 9 to 13
MJ/kg dry-matter would result in a major expense. The latter
diet would probably cost several times the former. On the other
hand an increase in calcium incorporation from 9 to 13 g/kg
dry-matter would probably, on its own, add little to the cost
of a ration. It is one of the weaknesses of linear programming
that it will work just as hard to meet each of these criteria.
Decisions in the real world of farming are not as clear-cut as
77
those in the manufacturing industries and really need
appropriate techniques to reflect this. There is a development
of classical linear programming methods which is called linear
goal programming. In this, the overall criteria are similar to
those set up in linear programs but in goal programming the
problem is expressed as a series of desirable objectives which
can be set in order of priority. For instance the most
important priority might be that a diet is produced with an HE
value of 11 MJ/kg and with crude protein level which differs
little from 160 g/kg. This is in fact the most important part
of the specification of the diet; for the given level of
production the animal needs its food and whatever price is
necessary must be paid. Reducing the price of the diet then is
of less importance. The third objective therefore becomes to
set the overall price of the diet as near as possible to the
cost of the cheapest ingredient. This is much closer to the
decision-making process which is adopted empirically by
farmers.
There are differences in the way in which two systems
arrive at feasible solutions; the older method uses the
technique of adding and subtracting 'slack' values of zero cost
to allow for the over- or under-supply of nutrients. In goal
programming a series of deviations from the goals or objectives
(the right hand side of classical LP) are set. The solution
uses an iterative procedure to reduce the overall deviation
from the desired values in order of priority.
Experiences with the preliminary versions of goal
programming have not shown any great deviations from the
solutions that would be reached using more conventional linear
programs. Advantages are likely to be more apparent when the
?roup of ingredients which is available to the procedure is
deficient in one or more of one of the minor components of the
diet.
CONCLUSION
Linear programming has proved itself to be a useful tool in the
formulation of diets in situations where some choice is
78
available in respect of the ingredients that may be
incorporated into diets for productive livestock. The
technology is available and the facilities are becoming more
common even in developing countries. In order to be able to use
the system there will be an increasing need for the compilation
of feed information, not only on the feeds themselves but also
on their properties after modification.
Future developments will include the adoption of more
appropriate optimisation methods that more closely parallel the
empirical thinking needed to make rational decisions in animal
production.
REFERENCES
Addison, K.B. 1952. The effects of various cultural and
manurial treatments on Napier fodder. Rhod. Agric. J.
53(4): 491.
ARC (Agricultural Research Council). 1980. The nutrient
requirements of ruminant livestock. Agricultural
Research Council, London, England.
ARC (Agricultural Research Council). 1984. The protein
requirements of ruminant livestock. Agricultural
Research Council, London, England.
Caird, L. and Holmes, W. 1986. The prediction of voluntary
intake of grazing cows. J. Agric. Sci., Camb. 107:43.
FEU (Feed Evaluation Unit). 1980. Third Annual Report of the
Feed Evaluation Unit. Rowett Research Institute,
Aberdeen, Scotland.
LP88. 1984. Linear Programming for the IBM Personal Computer.
Eastern Software Products, Inc., Virginia, USA.
Preston, T.R. 1986. Strategies for optimizing the utilization
of crop residues and agro- industrial by-products for
livestock feeding in the tropics. In: T.R. Preston and
M.Y. Nuwanyakpa, (eds), Towards optimal feeding of
agricultural by-products to livestock in Africa.
Proceedings of a workshop held at the University of
Alexandria, Egypt, October 1985. International Livestock
Centre for Africa, Addis Ababa, Ethiopia.
79
OVERCOMING THE CONSTRAINTS OF NITROGEN AVAILABILITY TO
IMPROVE CROP RESIDUE UTILISATION BY RUMINANTS IN BURKINA FASO
Kassu Yi lala
Semi -Arid Food Grain Research and Development
Co-ordination Office, OAU/STRC
B.P. 1783, Ouagadougou
Burkina Faso
ABSTRACT
The improvement in the efficiency with which ruminant animals
transform crop residues into meat, milk and draught power will
have important implications in the integration of animals in the
strongly cereal crop-oriented production system of the Soudanian
zone of Burkina Faso. There is a mismatching of supply of
nutrients and the physiological states of animals in the
production system. The abundant cellulosic energy could not be
utilised effectively mainly due to the constraint of nitrogen (N)
availability. The choice of source of N, non-protein or protein-
N, is crucial to the development of a feeding system that is
sound biologically and economically.
The biological aspects of utilisation of crop residues with
the aid of N supplements at ruminal and tissue levels are
discussed to justify the choice of source of N that could fit
into the objective conditions of the production system. The
production system could be responsive to changes if the
intervention is compatible with the long term productivity of
cereal crop production through improved soil fertility and
structure.
Amongst the sources of N emphasis was put on the use of
forage or dual-purpose legumes for they could serve as the key
link between animal and crop production systems, the latter
through increased soil N and organic matter (OM) status. The
80
patterns of j_n vitro degradation of OM and N of the forage
legumes and sorghum and millet stovers were assessed and briefly
discussed. It was shown that the forage legumes in addition to
correcting the deficiency of rumen degradable nitrogen (RDN), if
supplemented to cereal stovers, can also contribute a substantial
amount of rumen-degradable organic matter (RDOM). However, due
to the rapid degradation of N the available RDOM may not be able
to match to the former. Suggestions are given to increase the
supply of protein to the small intestine.
INTRODUCTION
Mixed crop-animal production occurs virtually throughout the
farming sectors of Burkina Faso. In the Soudanian zone cereal
crop sorghum and millet, production is the foundation of
agriculture and animal production the vital economic unit of the
system.
Declining crop yield/unit area accompanied by
progressively increasing requirement for food is forcing
farmers to cultivate more land at the expense of grazing
pasture and browses. The other aspect of this process is the
increase in the production of cereal crop residues. There is
already a heavy reliance on the use of the by-products as feed
during the long dry season, manifested by the large number of
ruminants concentrated in the zone, while moving from the Sahel
to the Guinean zones, immediately after harvest of cereals.
It is well documented that the utilisation of the energy
components of such materials by ruminant animals is highly
dependent on the efficiency of the fermentative activity of the
microbes in the rumen. For optimum or maximum fermentation on
a given diet a certain level of ammonia (NH,) concentration in
the rumen is required. Otherwise feed intake may be reduced if
NH, concentration is limiting the rate of fermentation (Mehrez
et al, 1977). Animals fed on such materials as their sole diet
show low dry-matter intakes and decline in liveweight. There
is ample evidence that with the inclusion of a source of
nitrogen, NPN or protein-N, positive responses in intake and
liveweight gain can be realised. In the Soudanian zone of
81
Burkina Faso, as in other semi -arid regions, nitrogen is the
most limiting nutrient for ruminant animal production.
Therefore, the incorporation of this nutrient in a feeding
system based on low-nitrogen fibrous diet is of paramount
importance. The attempt in supplementing with nitrogen should
be to maximise the utilisation of the residues through the
fermentative activities in the rumen and to realise as large
responses as possible at the tissue level of the host animal at
a given physiological state.
MISMATCHING OF SUPPLY OF NUTRIENTS AND PHYSIOLOGICAL STATES
OF ANIMALS IN THE SOUDANIAN ZONE OF BURKINA FASO
Improvement in animal, productivity requires improved nutrition
throughout the year with a guarantee for adequate supply,
quantitatively and qualitatively, in the latter part of
pregnancy, lactation and early growth periods. Orskov (1970)
and Kempton et al (1977) have demonstrated animal needs of
amino acids and glucose according to physiological states
(Figure 1). Such concepts could serve as guidelines to the
budgetting of available nutrients according to nutritional
needs of the animal. The demand for amino acids and energy (in
the form of glucose) are high during growth, late pregnancy and
lactation. In Burkina Faso the main calving, lambing or
kidding seasons are just before or during the rains (May/June),
but some births also take place in October/November just after
the rains, when cereal residues become abundant. The high
demand for nutrients during the last stage of pregnancy in the
former case, or during lactation in the latter, cannot be met
adequately from the natural pasture and cereal residues; the
nutritional status of the animals, lactation performance and
growth of the young are reduced, and are reflected by high
rates of pre-and post-weaning mortality of calves and lambs in
the semi -arid regions, depending on the month of the year
(ILCA, 1982).
82
Figure 1 Potential retention of N in relation to
digestible dry-matter intake ( ) and
glucose synthesis rate ( )in various
physiological states.*
N retained
g/IOOg ODM
2.0
Available
from
Microbial protein
it
0.4-
 
 
Early Lale
OROWTH
Early
MAINTENANCE PREGNANCY
GiUCOM
jynthsiii rat«
(g/Kga75/day)
r20
 
LACTATION
* Physiological
state Major sources of nutrients
Growth
- Preweaning - Might benefit from improved pasture between
July and September through dam's milk during
early pre-weaning period.
- Postweaning - Exposed to mature natural pasture and crop
residues.
Maintenance - If between October and June all animals are
exposed to standing mature dry pasture and
cereal residues.
Pregnancy - Last 10 to 8 weeks before parturition
exposed to extremely dry mature natural
pasture and cereal residues. Period of
severe deficit of nutrients.
Lactation - First 90 - 120 days lactating animals
exposed to improved grazing conditions to be
followed by cereal residues.
Sources: Orskov (1970); Kempton et al, (1977)
83
The nutrient yield from the natural pasture increases
between July and October, but the short rainy season accompanied
by high evapotranspiration and high temperature results in rapid
decline in the contents of nitrogen (Figure 2) and degradation of
organic matter (OM) in the rumen (Table 1).
When available, farmers use groundnut and cowpea haulms, the
latter grown in association with millet, to supplement cereal
residues to selected animals. However, the quantities produced
on the farm are not adequate to satisfy the requirements during
periods of high nutrient demand.
Table 1. j_n vitro dry-matter digestibility (DMD) and in-sacco
disappearance of DM of fallow natural pasture cut at
different stages of growth, Soudanian zone, Burkina
Faso.
Disappearance of DM
Date In vitro in the rumen
of DMD Incubat ion (h)
cutting (%) 0 48
21-08-85 63.4 26.7 71.4
11-09-85 61.4 22.7 65.5
20-02-85 59.1 19.6 55.6
23-10-85 57.1 15.7 58.7
14-11-85 54.1 13.7 57.9
LSD (P=0.05) 2.3 3.3 4.1
Source: Yilala (1986b).
BASIC PRINCIPLES FOR THE CHOICE OF SOURCE OF NITROGEN
TO UTILISE CEREAL BY-PRODUCTS
The feeding system that needs to be established under a
particular condition should be based on the universal biological
laws of nutrient utilisation by ruminants and also fit into the
economic realities of the production system. Some aspects of the
basic biological principles involved in the digestion in the
84
rumen and utilisation by the host animal of cereal residues
supplemented with NPN or protein-N, and the implications of these
principles on the choice of sources of nitrogen to fit into the
objective conditions of the production system in Burkina Faso
will be discussed briefly.
1. Biological
1.1 Effects of source of nitrogen on microbial digestion and
voluntary intake
Several studies have shown improvements in the intake of low-
nitrogen fibrous diets due to urea supplementation (Egan, 1965;
Egan and Moir, 1965; Kempton and Leng, 1979; Sriskandrajah et al,
1982), attributed to increased rate of digestion of cellulose in
the rumen (Egan, 1965; Egan and Moir, 1965), probably resulting
in increased rate of passage of feed, thereby possibly
alleviating a physical limitation to intake (Blaxter et al,
1961).
The degradation of urea is known to be too rapid (Johnson,
1976), indicating that the efficiency of utilisation could be low
when used with cellulosic diets, which yield energy too slowly
for the efficient capture of NH, by rumen micro-organisms
(Meggison et al, 1979). To realise a more effective utilisation
of urea its N may need to be released slowly (Orskov, 1982). The
synchronisation of rate of degradation of N and carbohydrate
components in the rumen is important for the synthesis of
microbial protein (Meggison et al, 1979; Satter and Roffler,
1981). Microbial protein synthesised in the rumen is the major
source of N to the host animal accounting for 60-85X of the total
amino acids entering the small intestine (Orskov, 1982). The
pattern of degradation, therefore, influences the choice of N
source for efficient utilisation of cereal residues. A rapid
degradation of N not matched to the release of OM from the
carbohydrate could lead to a high absorption of NH, from the
rumen (Meggison et al, 1979). The availability of suitable
carbon skeletons and ATP from plant material is a requirement for
the NH, released from dietary urea to be used for microbial
protein synthesis (Czerkawski, 1986).
85
Figure 2. Pattern of change in the proportion of N and NDF in the DM
of natural pasture on fallow land cut at different
intervals from August 21 to November 14, 1985
(Soudanian zone, Burkina Faso).
NDF content
(% DM)
rlOO
 
'9 '10
Date of cutting
26 59 84 79
Plant height (cm)
Source. Yilala (1986b).
86
The NH, not captured in the rumen is absorbed and converted
into urea, partly to be transferred to the rumen and influence
the digestion rate of cellulose or be lost in the urine depending
on the concentration of NH, in the rumen (Kennedy and Milligan,
1978). The synthesis of urea in the liver requires expenditure
of energy, each mole of urea requiring 4 moles of ATP (Martin and
Blaxter, 1965).
Compared with urea, protein-N sources could provide better
conditions for the digestion of cereal residues by the microbes
in the rumen, for the following reasons:
a. Although NH, is the major source of N for microbial growth,
some species are able to utilise or require the presence of
peptides and/or amino acids for growth (Cotta and Russel,
1982; Czerkawski, 1986; Harrison and McAllan, 1980; Maeng
and Baldwin, 1976; Pisulewski et al, 1981).
b. Due to the variation in degradabi lity, many protein-N sources
release NH, at slower rate than urea-N, more closely
coinciding with release of energy from the cellulosic
component and thus enhancing microbial production (Miller,
1982). This in turn will also stimulate increased rate of
cellulose digestion and voluntary intake.
c. Protein-N can also serve as a good source of sulphur which
usually is lacking in low-protein roughage diets (Miller,
1982). The supplementation of roughage diets with sulphur
showed increases in the digestion of cellulose (Gill et al,
1973; Gulati et al, 1985; Spears et al, 1976) for it is an
essential element for ruminal microbes (ARC, 1980; Spears et
al, 1976).
1.2 Effects of source of nitrogen on the response at the tissue
level
The animal is mainly dependent on volatile fatty acids (VFA) as
its source of energy. However, glucose is the major energy
component required for various metabolic processes in the tissue.
87
Because ruminants are unable to absorb sufficient glucose from
the digestive tract to meet their needs (Lindsay, 1980), the
availability of glycogenic materials such as propionic acid and
amino acids is essential (Kempton et al, 1977). The fermentation
of poor quality roughages such as cereal residues normally leads
to the production of high proportion of acetic acid (Thomas and
Rook, 1981) which is non glycogenic (Hovel I and Greenhalgh,
1978). Thus cereal residues cannot supply adequate energy for
the retention of N at the tissue level.
Under such conditions amino acids of microbial origin or
catabolised from the tissues might through gluconeogenesis supply
glucose for protein synthesis (MaCrae and Reeds, 1980), to
utilise acetate for lipogenesis (Hovel I and Greenhalgh, 1978),
and for urea synthesis in the liver (Martin and Blaxter, 1965),
indicating that the metabolism of absorbed amino acids
contributes also to energy metabolism. The transformation of
amino acids into glucose obviously reduces the efficiency with
which the former are utilised for tissue synthesis (MaCrae and
Reeds, 1980).
With no contribution from the urea to the energy pool the
low N balance values for the urea-N, as compared to protein-N
supplemented diets (Egan, 1965; Krzeminski, 1985) is not
surprising. The large increase in liveweight gain (Saadullah et
al, 1983; Kempton and Leng, 1979) or reduction in plasma urea and
increase in N retention (Krzeminski, 1985) due to the inclusion
of poorly degraded protein-N sources in straw diets containing
urea supplements might, at least partially, be associated with
the supply of glucose contributed by amino acids absorbed from
the small intestine. Besides this, the improvements in N status
of the animals were associated with increases in the intake of
the fibrous diets (Egan, 1965; Kempton and Leng, 1979).
2 Objective conditions of production system
From the above it is clear that the form of N supplementation of
cereal by-products should be considered if effective intervention
is desired at small-scale farm level. Quite often it is urea-N,
assumed to be easily available and cheap per unit of N, that is
88
considered to improve the utilisation of cereal residues, either
for direct supplementation or treatment of the by-product.
Treating residues with urea has been observed to enrich the N
content and result in positive effects on digestibility, intake
(Dolberg et al, 1981) and liveweight changes better than the
direct application prior to feeding (Orskov, 1981).
As a result of these and simplicity in the method of
treatment it is believed to be applicable under small-scale farm
conditions-. However, under the prevailing conditions in Burkina
Faso this does not appear to hold true, at least for the time
being, for two main reasons:
a. Treatment with urea requires large quantity of water (1 litre
of water/kg of straw; Dolberg et al, 1981); the principal
constraint of the production system in the Soudanian zone.
b. NH, loss could be up to 60% when straw is treated with urea
(Sundstol, 1981) and such losses cannot be justified under
conditions of limited N supply.
Protein-N sources such as oilseed cakes and those of animal
origin are produced in limited quantity and seem to be beyond the
economic reach of the farmers. The self-reliance of the farmer
in the source of N, therefore, is a prerequisite to improve the
efficiency of utilisation of the cereal residues and productivity
of animals.
Forage legumes have enormous potential under such
conditions. Since N is also the most limiting nutrient in the
soils of Burkina Faso, the production of forage, or dual-purpose
legumes could be compatible with the long-term productivity of
the production system comprising soil fertility through Np
fixation. The increase in cereal grain yield could be
accompanied with an increase in residue yield. Forage legumes
could, therefore, serve as the key link for effective integration
of animals into the strongly crop-oriented production system.
89
FORAGE OR DUAL-PURPOSE LEGUMES:
RELIABLE SOURCE OF N
Intercropping of cereals with legumes such as cowpea is a common
practice in the Soudanian zone of Burkina Faso. Groundnut is
grown as a sole crop on small plots of land. The residues of
these crops serve as sources of N to supplement the diets of
selected animals. However, the quantity produced on the farm is
low, compared to the DM of cereal residues, and cannot offset the
deficiency of N (Table 2).
Studies with forage and dual-purpose legumes on fallow land
showed the existence of great potential for the replacement of
poor fallow pasture with legumes which could be conserved as hay
for feeding as required. The legumes used were: Pol ichos
lablab. Stylosanthes hamata. Mac r opt i I ium atropurpureum. Vigna
unguiculata (local and improved varieties) and Phaseolus aureus.
In general legumes are known to be less dependent on soil N
for they obtain their N through biological fixation. As a
result, the N content of all the legumes during the period of
observation has always been above the critical level, for animal
use, at all stages of growth compared to the natural pasture
(Figure 3b). The critical level of N below which voluntary
intake of DM is depressed is 1.12% (Whiteman, 1980). As expected
there was a decline in the contents of N and increase in the
contents of the cell wall components (Figure 3a). Differences
were also noted in the solubility of DM due to species
differences and stage of growth (Table 3).
90
Table 2. Estimated yields of dry matter (DM), metabol isable
energy (ME) and rumen-degradable nitrogen (RDN) of
cereal residues, legume haulms and legume hays.
Cereal residue Legume haulms
Cowpea Groundnut Legume hay
Sorghum Millet Sole Intercrop Cowpea Di. lablab
DM yield (kg/ha)1 4209 3125 373 101 1497 3010 3010
ME yield (kg/ha)2 31568 16875 2611 707 11527 26187 34595
RDN yield (kg/ha)3 20 10 4.4 1.0 16.9 115 148
RDN required to match
ME yield (kg/ha) 40 21 3.3 0.9 14.4 33 43
RDN balance (kg/ha)4 -20 -11 1.1 0.1 2.5 82 105
1. Values are averages for different villages in the Soudanian zone,
Burkina Faso.
2. Calculated using the j_n vitro digestible organic matter values.
3. Refers to the 24 h j_n vi tro disappearance.
4. Assuming complete synchronization of release of energy and
nitrogen in the rumen.
91
Table3.Eisappearanceofdrymatt r(X)fo gelegumes,rownon fallowland,romny onbagsitherumenofc ttle
forincubationper dof0and48h.
Ageofcutting(days)
Species
00
49
S
84
Incubation(h)Incubation(h)
48
48
48
48
E^lablab(cvHighworth)
Viunguiculata( v00N-1)
P.aureus S.hamata
M^atropurpureum
52.9 46.5 45.1 37.3
00.9 88.8 82.9 72.3
55.9 00.6 46.2 36.4 36.4
89.648 3 79.943 1 86.348 1 81.134 8 64.53 2
55.148 083 55.800 18 7 86.042 55 E 75.932 54 62.23 358 8
Source:Yilala(1E86a).
Figure 3. Patterns of change in nitrogen (N) and neutral -
detergent fibre (NDF) contents of forage legumes
compared to fallow land natural pasture as growth
advances :□ = D. Lablab.
0 = V. unguiculata (cv KN.1),&= S hamata.
A = M. at ropurpur i um. #= P. aureus, x = natural pasture
NDF
(% DM)
80 n (a)
60
 
N
(% DM)
4J0-i
(b)
 
3.0
2.0-
I.O
Critical level of n
49 63 71
Age of cutting (dayi)
93
Considering the pattern of change with time in DM yield, N,
NDF and lignin contents, digestibility and solubility of DM, the
age of cutting that will fit into the conditions of the
production system for conservation as hay was identified. Under
the conditions of the Soudanian zone harvesting between 75 and 80
days of growth is suggested for all the species tested. This
coincides with the period at which the labour requirement for
cereal crop production is lowest, thus allowing the conservation
of forage legumes at the preferred stage of growth.
1 In vitro degradabi lity characteristics of forage legumes cut
at 75 days of growth
The presence of N in the diet does not always guarantee the
availability to the target microbes in the rumen. As noted
earlier it is influenced by the pattern of degradabi lity of the
protein. The amount of protein that reaches the small intestine,
besides degradabi lity, is also influenced by the outflow rate
from the rumen (Orskov and Robinson, 1981).
The pattern of N and 0M j_n vitro disappearance in this study
might indicate the characteristics of the legumes in their
degradation in the rumen. Such information might allow effective
screening of legumes to identify those whose N might be released
in synchronisation with the release of OM from the cereal
residues in the rumen (Table 4).
The results, however, need to be treated as indicative of
the pattern of degradation and not to be equated with in vivo
conditions. In addition to correcting the deficiency of rumen-
degraded nitrogen (RDN) to utilise the rumen-degraded organic
matter (RDOH) of the cereal crop residues, the forage legumes
94
could also contribute a substantial amount of OM digested in the
rumen. However, the N components of these legumes were rapidly
degraded with a disappearance of not less than 80% within 6 hours
of incubation.
ARC (1980) estimated the ratio of RDM: ROOM required in the
rumen to be 1:33.3. Based on this the ON and N releases of
cowpea and millet stover were assessed for illustration purposes
(Figure 4). In Figure 4 (a) it is noted that the OH released
from the millet stover may not be utilised completely because of
the inadequacy of N contained in it. Figure 4 (b) might
illustrate a situation where cowpea N, is degraded rapidly and
may not get adequate amount of ON released to match it, and the
excess N could be lost in the urine. It is possible that the
combination of the OM from cowpea and millet stover too may not
provide adequate OM to match the N degraded (Figure 4(c)).
In places where conditions permit, forage proteins of high
degradability could be treated with chemicals such as
formaldehyde to increase their passage to the small intestine to
be absorbed as amino acids. Whereas, in places where such
possibilities do not exist, for example in Burkina Faso, other
alternatives that could fit into the system need to be sought.
2 Suggestions to improve the utilisation of forage protein-N
There are reports (Kempton and Leng, 1979; Hacrae and Ulyatt,
1980; Orskov and Robinson, 1981) which indicate protein
deposition in animals to be positively related to the amount of
amino acids absorbed from the small intestine. Such responses
are higher in those animals fed rations with lower rather than
higher concentration of degradable N (Cummins et al, 1980; Yilala
and Bryant, 1985).
95
Figure4:IllustrationofreleaseoOMandNi :( )milletstover(Nli.i ingfoON
released),(bCowpeaONli.itingforNreleased),an(cmilletstover+
cowpea(ONlimitingforNreleasedai lyea lierhoursfinc bation).
 
(b)
OMrequired
-.-—T-'
 
.005
Timeofincubation(h)
In order to improve the supply of protein to the small
intestine when forage legumes are to be included in crop residue
basal diets the following suggestions may help:
a. Increase the level of readily fermentable carbohydrate to
capture the degraded N for microbial synthesis to be
absorbed as amino acids of microbial origin. Probably
growing the legumes in association with grass species with
known water soluble carbohydrates and adopted to the
climatic conditions of the semi- arid region might help.
Chopping the straw might increase the overall digestible
organic matter in the rumen.
b. Combine the particular forage legume with other protein-N
sources of less degradabi I ity so that the absorption of amino
acids from the dietary source could be increased at the small
intestine. Since protein-N of animal origin and oilseed
cakes are scarce, legume forages and browses containing
tannins could be introduced. Legumes containing a certain
level of condensed tannins are known to increase the
quantity of amino acids absorbed in the small intestine
(Barry and Manley, 1983; Waghorn et al, 1987), although
condensed tannins can also depress digestion in the rumen
of the carbohydrate components (Barry and Manley, 1983).
In conclusion, the objective realities in the Soudanian zone
of Burkina Faso favour the creation of conditions that will allow
the effective integration of ruminant animals into the crop
production system through recycling of resources. Forage legumes
possess enormous potential as sources of N and could serve as the
key link in the integration of crop and animal production systems
97
(Table 5). So far farmers have not given due importance to the
incorporation of forage crops in the system. Possibilities that
could increase the production of forage proteins do exist:
a. Replacement of poor fallow pasture with forage legume/cereal
rotation.
b. Intercropping cereals with forage or dual-purpose legumes.
c. Production of browses along contour bunds or alley cropped
with cereals.
ACKNOWLEDGEMENTS
The author is grateful to Mr. S. Zoundi and technical assistants
for providing all the necessary help for the trials. The
financial assistance of SAFGRAD (Semi-Arid Food Grain Research
and Development) and the provision of facilities by INERA
(Institut national pour I'etude et la recherche agronomique) are
gratefully acknowledged.
REFERENCES
ARC (Agricultural Research Council). 1980. The nutrient
requirements of ruminant livestock. Commonwealth
Agricultural Bureaux, Farnham Royal, UK.
Barry, T.N. and Manley, T.R. 1983. Quantitative digestion
studies in sheep fed vegetative Lotus pedunculatus with
different contents of condensed tannin. Proc. Nutr.
Soc. New Zealand 8: 140-141.
Blaxter, K.L.; Wainman, F.D. and Wilson, R.S. 1961. The
regulation of food intake by sheep. Anim. Prod. 3: 51-61
98
Cotta, M.A. and Russell, J.B. 1982. Effect of peptides and
amino acids on efficiency of rumen bacterial protein
synthesis in continuous culture. J. Dairy Sci. 65: 226-
234.
Cummins, K.A., Nocek, J.E. and Polan, C.E. 1980. Growth and
nitrogen balance of calves fed rations of varying
degradabi lity and physical form. J. Dairy Sci. 65: 773-783.
Czerkawski, J.W. 1986. An introduction to rumen studies.
Pergamon Press, Oxford.
Dolberg, F.; Saadullah, M. and Haque, R. 1981. Straw treatment
in a village in Noakhali district, Bangladesh. In: M.G.
Jackson, F. Dolberg, C.H. Davis, M. Haque and M. Saadullah
(eds), Maximum livestock production from minimum land.
Proc. Seminar held in Bangladesh, Feb. 1981. Bangadesh
Agricultural University, Mymensingh, Bangladesh. pp. 205-
224.
Egan, A.R. 1965. Nutritional status and intake regulation in
sheep. III. The relationship between improvement in
nitrogen status and increase in voluntary intake of low-
protein roughages by sheep. Aust. J. Agr. Res. 16: 463-
472.
Egan, A.R. and Moir, R.J. 1965. Nutritional status and intake
regulation in sheep. I. Effects of duodenal ly infused
single doses of casein, urea and propionate upon
voluntary intake of a low-protein roughage by sheep.
Aust. J. Agr. Res. 16: 437- 449.
Fall, A.; Diop, M.; Sanford, J.; Wissocq, Y.J.; Durkin, J. and
Trail, J. CM. 1982. Evaluation of the productivities of
Djallonke sheep and N'Dama cattle at the Centre de
Recherches Zootechniques, Kolda, Senegal. ILCA Research
Report, No. 3, ILCA, Addis Ababa, Ethiopia.
99
Gill, L.A.; Shirley, R.L. and Moore, J.E. 1973. Effect of
methionine hydroxy analog on bacterial protein synthesis
from urea and glucose, starch or cellulose by rumen
microbes in vitro. J. Anim. Sci. 37: 159-163.
Gulati, S.K.; Ashes, J.R.; Gordon, G.L.R. and Phillips, M.W.
1985. Possible contribution of rumen fungi to fibre
digestion in sheep. Proc. Nutr. Soc. Austr. 10: 96-106.
Harrison, D.G. and McAllan, A.B. 1980. Factors affecting
microbial growth yields in the reticulo-rumen. In: Y.
Ruckebusch and P. Thivend (eds), Digestive physiology
and metabolism in ruminants. MTP Press Ltd., Lancaster,
pp. 205-226.
Hovell, F.D. and Greenhalgh, J.F.D. 1978. The utilization of
diets containing acetate, propionate orbutyrate salts by
growing lambs. Br. J. Nutr. 40: 171-183.
Johnson, R.R. 1976. Influence of carbohydrate solubility on
non protein nitrogen utilization in the ruminant. J. Anim.
Sci. 43:184-191.
Kempton, T.J. and Leng, R.A. 1979. Protein nutrition of growing
lambs. 2. Effect on nitrogen digestion of supplementing a
low-protein cellulosic diet with either urea, casein or
formaldehyde-treated casein. Br. J. Nutr. 42: 303-315.
Kempton, T.J.; Nolan, J.V. and Leng, R.A. 1977. Principles of
the use of non-protein nitrogen and by-pass proteins in
diets of ruminants. World Animal Review (FAO) 22: 2-10.
Kennedy, P.M. and Milligan, L.P. 1980. The degradation and
utilization of endogenous urea in the gastrointestinal
tract of ruminants: A review. Can. J. Anim. Sci. 60: 205-
221.
100
Krzeminski , J.; Kulasek, G.; Motyl, T.; Jaworska, K.;
Leontouricz, H. and Kozlowski, B. 1985. Protein
supplement resistant against ruminal degradation as a
factor improving utilization of urea in ruminant feeding.
Archiv fur Tierernahrung. 35: 401-409. (Abstract (En): SDI
Service-ILCA).
Lindsay, D.B. 1980. Amino acids as energy sources. Proc. Nutr.
Soc. 39: 53-59.
MacRae, J.C. and Reeds, P.J. 1980. Prediction of protein
deposition in ruminants. In: P.J. Buttery and D.B. Lindsay
(eds), Protein deposition in animals. Butterworths,
London. pp. 225-250.
Maeng, W.J. and Baldwin, R.L. 1976. Factors influencing rumen
microbial growth rates and yields. J. Dairy Sci. 59: 643-
647.
Martin, A.K. and Blaxter, K.L. 1965. The energy cost of urea
synthesis in sheep. European Association for Animal
Production Publication No. 11, Academic Press Inc., London,
UK. pp. 83-97.
Meggison, P. A.; McMeniman, N.P. and Armstrong, D.G. 1979.
Efficiency of utilization of non-protein nitrogen in
cattle. Proc. Nutr. Soc. 38: 147A.
Mehrez, A.Z.; Orskov, E.R. and McDonald, I. 1977. Rates of rumen
fermentation in relation to ammonia concentration. Br. J.
Nutr. 38: 437-443.
Miller, E.L. 1982. The nitrogen needs of ruminants. In: D.J.
Thomson, D.E. Beever and R.G. Gunn (eds), Forage protein in.
ruminant animal production. BSAP Occasional Publication
(UK), No. 6, British Society of Animal Production, Surrey,
UK. pp. 79-87.
101
Orskov, E.R. 1970. Nitrogen utilization by the young ruminant.
In: H. Swan and D. Lewis (eds), Proceedings of the 4th
Nutrition Conference for Feeds Manufacturers, University of
Nottingham, London.
Orskov, E.R. 1981. Nutritional evaluation of poor quality
roughages. In: M.G. Jackson, F. Dolberg, C.H. Davis, M.
Haque and M. Saadullah (eds), Maximum livestock production
from minimum land. Proceedings of a Seminar held in
Bangladesh, Feb. 1981. Bangladesh Agricultural University,
Mymensingh, Bangladesh. pp. 70-87.
Orskov, E.R. 1982. Protein nutrition in ruminants. Academic
Press, London.
Orskov, E.R. and Robinson, J.J. 1981. The application of modern
concepts of ruminant protein nutrition to sheep production
systems. Livestock Prod. Sci. 8: 339-350.
Pisuleuaki, P.M.; Okorie, Q.L.; Buttery, P. J.; Haresign, W. and
Lewis, D. 1981. Ammonia concentration and protein
synthesis in the rumen. J. Sci. Food. Agric. 32: 759-766.
Saadullah, M.; Haque, M.; Thomson, K.V.; Moller, P.O. and
Sorensen, A.N. 1983. Response of calves fed ammonia
treated straw to increasing levels of fishmeal. In:
Maximum livestock production from minimum land. Proc.
4th seminar held in Bangladesh, May 1983. Bangladesh
Agricultural University, Mymensingh, Bangladesh.
Satter, L.D. and Roffler, R.E. 1981. Influence of nitrogen and
carbohydrate inputs on rumen fermentation. In: W. Haresign
and D.J. A. Cola (eds), Recent developments in ruminant
nutrition. Butterworths, London. pp. 115-139.
102
Spears, J.W.; Ely, D.G.; Bush, L.P. and Buckner, R.C. 1976.
Sulphur supplementation and jjn vitro digestion of forage
cellulose by rumen micro-organisms. J. Anim. Sci. 43:
513-517.
Sriskandrajah, M.; Ke 1 1 away, R.C. and Leihbolz, J. 1982.
Utilization of low quality roughages: Effects of
supplementing with casein treated or untreated with
formaldehyde on digests flows, intake and growth rate of
cattle eating wheat straw. Br. J. Nutr. 47: 553-563.
Sundstol, F. 1981. Results of some experiments on ammonia-
treated straw. In: M.G. Jackson, F.Dolberg, C.H. Davis,
M. Haque and M. Saadullah (eds), Maximum livestock
production from minimum land. Proceedings of a Seminar held
in Bangladesh, Feb. 1981. Bangladesh Agricultural
University, Mymensingh, Bangladesh, pp. 97-102.
Thomas, P.C. and Rook, J.A.F. 1981. Manipulation of rumen
fermentation. In: W. Haresign and D.J. A. Cole (eds),
Recent developments in ruminant nutrition. Butterworths,
London.
Waghorn, G.C.; Ulyatt, M.J.; John, A. and Fischer, M.T. 1987.
The effect of condensed tannins on the site of digestion
of amino acids and other nutrients in sheep fed on Lotus
corniculatus: Br. J. Nutr. 57: 115-126.
Whiteman, P.C. 1980. Tropical pasture science. Oxford
University Press, Oxford.
Yilala, K. 1986a. Preliminary investigation on the establishment
of forage legumes on fallow land and assessment of their
nutritive value at different stages of growth. In: Farming
Systems Research Report (SAFGRAD/INERA). Ed. Co-ordination
Office - OAU/STRC/SAFGRAD, Ouagadougou, Burkina Faso.
103
Yilala, K. 1986b. Assessment of the nutritive value of natural
pasture on fallow land at different stages of growth. In:
Farming Systems Research Report (SAFGRAD/INERA). Ed.
Co-ordination Office - OAU/STRC/SAFGRAD, Ouagadougou,
Burkina Faso.
Yilala, K. and Bryant, M.J. 1985. The effects upon the intake
and performance of store lambs of supplementing grass
silage with barley, fishmea' and rapeseed meal. Anim.
Prod. 40: 111-121.
104
STRATEGIES TO OVERCOME CONSTRAINTS IN EFFICIENT UTILIZATION
OF AGRICULTURAL BY-PRODUCTS AS ANIMAL FEED
L.P. Nkhonjera
Department of Animal Health and Industry, Malawi
ABSTRACT
The constraints in the efficient utilisation of agricultural
by-products have been poor quality of the by-products,
financial limitations for the procurement of chemicals and
reagents and inadequate qualified manpower to carry on
analytical work. Associated with this are inadequate
laboratories and other facilities, lack of documented work on
previous research work on the nutritive value of these feed
resources making it impossible to derive suitable feed
combinations for the various nutrient requirements. In general
a strategy to promote the utilisation of by-products has been
lacking and consequently affecting the development of the
livestock industry. Intensive livestock production systems are
currently implemented on a stratified model on a small scale.
However simple formulated rations on a small scale have been
used in beef cattle fattening and daily cattle feeding. The
resulting daily liveweight gain of 1 kg and milk yields of up
to 16 litres respectively have been encouraging. Lambs
fattened on groundnut haulms and maize bran have shown daily
weight gain of 112 g.
INTRODUCTION
The policy of the Government of Malawi is to be self-sufficient
in food and sell the surplus. In the field of livestock
efforts are concentrated on developing and intensifying rural
animal production to provide adequate animal products with the
objectives to improve the diet of the population and raise the
rural income.
105
Malawi is a land-locked country with a total land area
of 119,140 sq.km. Twenty percent of this land is under water.
Of the remainder, 25 percent is steep land with slopes of 12.5
percent and above.
At present there is very little unused land that can be
opened up for cultivation. Whatever little there is, it is
generally confined to parts of the less densely populated
Northern region. The livestock population is 1,010,659 cattle,
165,482 sheep and 789,300 goats. The ratio of man to cattle is
7:1 indicating the likely future shortages of meat if cattle
remain to be its main source. Some attention is given to
improving the productivity of the small stock. Goats and sheep
are being improved under a crossbreeding programme and
evaluations made of their performance. The suitable breeding
stock will in turn be sold to smallholder farmers. A future
programme to be promoted along with sheep farming would be
fattening of lambs on agricultural by-products as the feed
base. A lamb-fattening trial on the same feed base is being
carried out to evaluate the performance. The overall objective
is to promote a strategy whereby breeding is undertaken in
rural grazing areas whereas stock would be finished on
agricultural by-products in arable farming areas.
This paper describes the contributing factors to the
inefficient utilisation of by-products that the country has
experienced and ways of overcoming them.
As already mentioned, the agricultural policy has
emphasised on increased crop production. This has led to an
increase in crop residues and other by-products on smallholder
farms and estates, in milling companies, breweries and other
processing organisations. These by-products are likely to
assist in increasing the carrying capacity of the land.
CONSTRAINTS
The grazing lands in Malawi are at or near their sustainable
carrying capacity. There is therefore an increasing need to
provide supplementary feed to sustain and improve animal
106
protein production. Crop and agro- industrial by-products thus
have a significant contribution to make as a cheap and
renewable source of animal feed.
The following constraints are reckoned the most
important limitations to utilise agricultural by-products with
maximum efficiency. Table 1 shows the quantities of
agricultural by-products Malawi produces.
Table 1. Basic statistics on the production of crop residues
and crop by-products (tonnes).
Area Kernel Crop residue Bran/
Crop planted
(ha)
production production cakes
Mai ze 1,144,850 1,355,200 2,710,400 433,664
Rice 20,807 34,265 34,265 3,426
Wheat 1,126 787 787 197
Groundnuts 135,966 62,240 62,240 31,140
Source: Munthali and Dzowela (1987).
Nutritive values of these feed resources can be improved
by chemical treatments as it is done elsewhere. This approach
has certain limitations and implications:
1. Well-equipped laboratories are required to analyse untreated
and treated feed resources.
2. The result of feeding treated feeds would be animal products
at unaffordable prices. This would further result in a
reduction in protein intake.
3. There is an acute shortage of qualified staff to measure and
categorise the nutritive value of all crops and agricultural
by-products. In addition chemicals and reagents to be used
are also expensive.
107
4. Besides the research work done in the early 1960s on
nutritive value of maize bran, maize stover and groundnut
haulms, there is no documented information on these values
or their combinations to provide the level of or nutrients
required by the respective classes of livestock. The
consequence of this is that livestock have been inadequately
fed and hence delayed to reach slaughter weights.
5. Availability of these by-products is limited to areas
favoured with a climate suited to crop production. In most
cases these areas may not necessarily be blessed with
livestock resources or good market infrastructures.
6. There is in general lack of a clearly defined overall
strategy in the utilisation of agricultural by-products.
As a result emphasis on diversification has lacked and
that livestock programmes have not been well integrated in
crop farming.
STRATEGIES TO IMPROVE THE EFFICIENCY
IN UTILISATION OF AGRICULTURAL BY-PRODUCTS
The by-products of maize stover, maize bran, rice bran, wheat
middlings, cottonseed cake and molasses are becoming more
abundant to be used as ingredients in cheap livestock rations.
The following measures are being taken in order to promote the
utilisation of these by-products:
1. Emphasis is on stratification of livestock production and
integration into the cropping systems so as to minimise
competition for resources, and to promote stable mixed
farming as well as to optimise production of scarce animal
protein.
2. Use of agricultural by-products in animal feeding is
optimised to overcome periods of feed shortage and at the
same time to ensure a constant supply of livestock products
throughout the year.
3. The setting up of livestock feed mixing companies close to
arable cropping areas is encouraged.
108
4. The long existing companies have compounded rations from
ingredients which are products of milling and oil companies
and abattoirs while importing vitamineral premixes. The
supply of these ingredients is not constant. At the same
time imported ingredients are expensive. The larger
proportion of the livestock industry is rural -based. The
economics of marketing do not however encourage the use of
these expensive commercial feeds. In some parts of the
country which are close to sugar companies and cotton-
growing areas, rations are being compounded for use by
smallholder farmers. Table 2 shows an example of a ration
compounded near the source of ingredients.
Table 2. Composition of the smallholder dairy ration.
Kg/100 kg of CP% Kg TON
Ingredient concentrate %
2.7
10.0 18.2
0.4 6.8
5.5 47.6
100.0 18.6 73.6
Source: Cattle Feedlot Company, Malawi, 1986.
The main concentrate in dairy feeding for a long time
has been maize bran with crude protein percentages ranging
from 8-10.7. The ration in Table 2 provides crude protein of
18.6. Average daily milk yields of 7 kg when feeding dairy
cows on maize bran have increased to 16 kg when cows of high
milk yielding breed are fed on the ration.
Urea 1.0
Cottonseed cake 25.0
Molasses 10.0
Maize bran 61.0
Monocalcium phos;ph ate 2.0
Salt 1.0
109
5. The farmers have been organised into groups to ease feed
transport problems associated with distance. An individual
would find it impossible and expensive to hire a vehicle to
collect feeds. It has become possible on a co-operative
basis.
EXAMPLES OF PROGRAMMES TO DEMONSTRATE
IMPROVED UTILISATION OF BY-PRODUCTS
Under range conditions the average daily liveweight gain of
0.23 kg has been recorded (Department of Animal Health and
Industry, Malawi, unpublished). When fed on agricultural
products of maize stover (3.2% CP) and groundnut haulms (11.2%
CP) recorded daily weight gain averaged 0.5 kg (Agyemang and
Nkhonjera, 1984). The daily weight gain of 1 kg which is
commonly recorded at the Cattle Feedlot Company demonstrates
that a possibility still exists to improve the efficiency of
utilisation of agricultural by-products under smallholder
programmes. The ration composed of molasses, bagasse,
cottonseed cake, rice husks, cottonseed husks, wheat offals and
hominy cop is a rich one. This ration could also be available
for use by smallholder feeder farmers.
Dairy farming and cattle fattening have been implemented
for sometime now, though at a small scale. However, as the
country's demand for lamb and mutton has not been satisfied,
sheep and goat farming is being promoted along with lamb
fattening in areas not covered by any of the above systems.
Use is made of by-products that have been lying idle in the
past.
This approach would obviously encourage the expansion of
intensive livestock production systems in areas with abundant
supply of by-products. The performance of lambs of various
breeds is shown in Table 3.
110
62 105 11.9 11.7 41.1
58.0 149 10.7 10.4 36.4
73 111 11.2 11.1 41.4
64 112 11.6 11.4 40.5
Table 3. The results of a lamb-fattening trial under
smallholder conditions.
Issue DWG
wt Final both to DWG
No. of animals (x) wt start of trial HWD CDW Kill-
in breed group (kg) (kg) (g/d) (g/d) (kg) (kg) ing 1/2
Local (18) 17.5 28.8
Dolpe x Local (4) 15.0 29.5
Dorper (6) SD 14.9 26.9
All breeds (28) 16.7 28.5
DWG = daily weight gain.
HDW = hot pressed weight.
CDW = cold dressed weight.
Source: Sill and Munyenyembe (1986).
On a fattening period of 107 days the animals gained on
average 112 g. The killing-out percentage was 41% on average.
All animals were graded choice and some prime (the top most
grades). An expansion of such programmes makes it easier to
utilise the by-products where they are not in use.
The Government in collaboration with the Food and
Agriculture Organization (FAO) has currently conceived a
project to improve the utilisation of crop and agro- industrial
by-products in animal feeding. Some of the activities to be
carried out are:-
1. Conducting a comprehensive and qualitative survey of feed
value present and potential crop and agro- industrial by
products suitable for animal feeding.
2. Assessing the capacity and identifying the needs of the
Department of Animal Health and Industry to enable it to
meet its requirements for the utilisation of animal by
products.
Ill
3. Sending staff overseas for training on the processes
involved in the utilisation of by-products.
4. Formulating by-product utilisation strategies using standard
feed analysis tables and local laboratory analysis including
on-farm testing.
CONCLUSION
The availability of agricultural by-products is justified by
the level of agricultural development in the country. This
provides the greatest opportunity for the development of a
livestock programme that would use these by-products as
livestock feed. The Department and related institutions are
concentrating their attention on defining the most economic and
acceptable ways of utilising these by-products because the
future of the livestock industry is likely to depend on them.
REFERENCES
Agyemang, K. and Nkhonjera, L.P. 1984. Evaluation of
crossbred cattle productivity on the smallholder dairy
farms and on government farms in the Republic of Malawi.
A joint report by the Government of Malawi and the
International Livestock Centre for Africa. ILCA, Addis
Ababa. 81 pp.
Department of Animal Health and Industry, Malawi. 1984.
Evaluation of the Mjinge and utilisation scheme. (A paper
for official use by the department).
Munthali, J.T. and Dzowela, B. 1987. Inventory of livestock
feeds in Malawi. In: J. A. Kategile, A.N. Said and B H
Dzowela (eds), Animal feed resources for small-scale
livestock producers. Proceedings of the Second PANESA
Workshop held in Nairobi, Kenya, 11-15 November 1985.
IDRC-MR 165e. International Development Research Centre,
Ottawa, Ontario.
Musa, F.A.; Nkhonjera, L.P. and Mkandawire, R.C.J. 1986.
Productivity of dairy cows under smallholder farms based
on agro by-products. Working paper presented at the
African Research Network on utilisation of agricultural
by-products.
112
Nkhonjera, L.P.; Agyemang, K. and Butterworth, M. 1987. The
performance of cattle stall fed for beef in Malawi.
Tropical Agriculture (Trinidad) 64 (2): 105-110.
Preston, T.R. and Leng, R.A. 1986. Matching livestock
production systems to available resources. Pretesting
edition. ILCA, Addis Ababa, Ethiopia. 331 pp.
Sill, 0. and Munyenyembe, R.A.D. 1986. Fat lamb production
under smallholder conditions. Unpublished report for
official use by Malawi Government.
113
TOWARDS EFFICIENT UTILIZATION OF POULTRY WASTE BY RUMINANTS
E. K. Odhuba
Animal Production Research Centre, Muguga; Kenya Agricultural
Research Institute, P.O.Box 21, Kikuyu, Kenya
ABSTRACT
Feeding experiments were conducted to evaluate the utilization
of poultry waste-based diets by cattle. Sunflower seed cake
could be replaced completely by broiler litter to constitute
30% of finishing rations for steers without affecting average
daily gain or carcass merit. Cross-bred heifers which were
supplemented with a fermented 60:40 poultry layer waste/ground
sorghum grain were able to attain a breeding weight of around
260 kg by 18 months of age. In both experiments, dry-matter
intake and digestibility coefficients of poultry waste-based
diets were comparable to commercial -type rations. Ensiling
sorghum forage (Sorghum vulgare) with layer waste making up 40%
of the ensiled material improved crude protein (CP) from 6.5%
in untreated silage to 12.2% in the treated silage. Steers
that were supplemented with treated silage gained 0.87 kg/day
and this was raised to approximately 1 kg/day when 1 kg of
ground grain per day was fed in addition to treated silage. A
ration compounded with 30% of the concentrate mixture as
poultry waste could support about 10 litres of milk per day.
Inclusion of the waste did not affect butter fat content of the
milk. It would appear that CP values of around 12% in
concentrate mixtures may be adequate for low producing dairy
cattle.
114
INTRODUCTION
Poultry waste, also referred to as poultry litter or poultry
manure, has been used as a fertilizer mainly to supply
nitrogen to the soil. Chemical analysis shows that crude
protein (CP) in poultry waste varies between 14 and 30% on dry-
matter (DM) basis (Bhattacharya and Taylor, 1975; Smith et al,
1979). The nitrogen can be utilized up to ten times more
efficiently when recycled through ruminants as a feed (Smith
and Wheeler, 1979). Micro-organisms in the rumen have the
unique ability of utilising uric acid and other forms of non
protein nitrogen (NPN) contained in the waste to make their own
body protein which is subsequently digested in the lower gut
for use by the host animal. The rumen microbes also degrade
cellulosic materials used as bedding contained in the waste.
The latter also contains high levels of calcium and phosphorus
and can also be an important source of energy, yielding about
9.1 MJ per kg, which compares favourably with lucerne hay
(Bhattacharya and Fontenot, 1966). The waste often includes
varying proportions of high quality spilled chicken feed which
may contribute significantly to its feeding value. However,
its real feeding value is attributable to the provision of NPN
rather than energy.
PROBLEMS ASSOCIATED WITH THE USE OF POULTRY WASTE AS A FEED
In feeding poultry waste, it is important to note that
depending on the type and standard of management of the birds,
the material may be a potential source of harmful agents
including pathogenic bacteria (e.g. Salmonella), moulds and
yeasts (Alexander et al, 1968). Also there may be problems
associated with nutrient loss mainly through volatilisation of
ammonia (Caswell et al, 1975). Besides, some forms of poultry
waste e.g. caged-layer waste (CLW) have a particularly
115
offensive odour and are rather messy to handle. Lastly, the
high ash content especially in CLW tends to reduce the energy
value of the waste.
PROCESSING AND FEEDING OF POULTRY WASTE
In attempting to obtain a stable and safe material, some form
of processing is desirable. For instance, Fianu et al (1984a)
treated CLW by air-drying, ovenheating and autoclaving but none
of these methods was satisfactory for the simultaneous control
of obnoxious odour, pathogens and nitrogen loss. Besides, the
expenses incurred would be prohibitive to a large section of
the farming community. It is imperative, therefore, that only
the waste from healthy and properly managed birds, preferably
on concrete floors, should be used, the idea being to start
with material with a low bacterial count.
The waste should be thoroughly raked, removing any caked
material and left to dry in situ for at least three days. The
material is subsequently milled through an 8-10 mm sieve to
facilitate mixing with other feed ingredients. Poultry layer
waste from deep litter houses does not, usually, require any
milling. Further processing, if necessary, may be achieved by
composting or deep stacking (Fontenot and Jurubescu, 1980) or
better still and rather more cheaply, by ensiling (Harmon et
al, 1975). Ensiling subjects poultry waste to a chemical
process known as fermentation, in which soluble sugars are
hydrolysed enzymat ical ly by aerobic micro-organisms into acetic
and lactic acids. Any pathogenic bacteria present in the waste
are killed as a result of high temperatures and accumulation of
these acids. In addition, these acids have a deodorising
effect on the waste which acquires a pleasant aroma, thereby
enhancing palatability and voluntary dry-matter intake by the
animal. Johnson et al (1967) quoted work that showed NPN was
116
more efficiently utilised by ruminants when added to plant
material at ensiling time rather than when added to silage at
feeding time. This was attributed to the improved nutrient
composition of the silage arising from the sparing effect that
NPN has on the degradation of protein in the forage. Ensiling,
therefore, provides a technique for using NPN in amounts
greater than can be used effectively by direct feeding.
Besides, the method helps to preserve nutrients which can be
used as and when required in addition to improving storage
characteristics. Good silages have been made with up to 45% of
the total DM contributed from poultry waste (Harmon et al,
1975). Baugarski et a I (1980) obtained quality maize silage in
the laboratory using up to 55% DM as broiler litter.
The amounts of poultry waste that can be fed would
depend on plane of nutrition, production intensity and protein
content of the waste. In general, the waste can supply 30-90%
of the total protein requirements for ruminants (Shah and
Muller, 1983). However, such rations must be fortified with
readily fermentable carbohydrate to supply the energy required
by the rumen micro-organisms to be able to handle the NPN more
efficiently. An optimal inclusion level of 10% of the waste DM
with molasses was suggested by Harmon et al (1972). Addition
of molasses would also improve pal stability and hence voluntary
intake.
FEEDING OF POULTRY WASTE-BASED RATIONS-THE KENYAN EXPERIENCE
1. Utilisation of broiler litter in finishing rations for
steers
Objective-To feed finishing steers with broiler litter-based
diets so as to improve carcass grade and also promote
liveweight gain in a semi - intensive production system.
117
Materials and Methods - Four groups of steers each weighing
from 240-315 kg liveweight (Boran and Boran x Hereford
crossbred) were grazed a predominantly Rhodes grass (Chl or is
gayana) pasture during daylight hours and supplemented during
the night with finishing rations at the rate of 2 kg ground
sorghum grain (Sorghum vulgare) and 1 kg mixture of broiler
litter, sunflower seed cake (SSC), molasses, grass hay and
mineral mix in the rations indicated in Table 1. These rations
were compounded to give average daily gain (ADG) of around 0.8
kg. The fifth group was a negative control and was
supplemented with Rhodes grass hay ad libitum.
Table 1. Composition of supplementary rations for finishing
steers.
Ingredient
Ration kg (dry-matter basis)
Hay
Sunflower seed cake
Broiler litter
Sugarcane molasses
Sorghum meal
Ground grass hay
Unground grass hay
Mineral Mix *,g
*
Obtained from Pfizer Laboratories, Nairobi
0 1.0 0.6 0.3 0
0 0 0.36 0.63 0.9
0 0 0.04 0.07 0.1
0 2.0 2.0 2.0 2.0
0 1.0 1.0 1.0 1.0
Ad lib 0 0 0 0
150 150 150 150 150
118
Digestibility coefficients of the five supplemental
rations were determined using another set of three steers per
diet in conventional metabolism stalls. Animals were
slaughtered after a feeding period of 110 days and carcass
grades were assessed by the Kenya Meat Commission (KMC)
graders. Percentage fat in the carcasses was determined by the
10th rib method as described by Ledger et al (1973).
Results - Tables 2 and 3 summarise the results of DM intake and
digestibility, ADG and percent fat, respectively. Inclusion of
broiler litter in finishing concentrate rations did not affect
intake or digestibility which was consistent with the results
reported by Kayongo and Irungu (1986) using sheep. Liveweight
gains of supplemented animals were similar regardless of
whether broiler litter or SSC was the source of nitrogen.
Steers which were fed on a diet in which broiler litter
replaced all the SSC gained, on average, 0.6 kg/day, slightly
below the expected 0.8 kg/day, probably due to the severe dry
conditions during the experimental period. For the same
reason, carcass fat content fell short of the optimal levels of
22-26% (Ledger et al, 1973). However, all carcasses of animals
supplemented with SSC or broiler litter-based rations were High
Grade and well-fleshed with even fat cover. Details of this
trial have ben reported by Odhuba et al (1986a).
119
Table 2. Mean DM intake and digestibility of rations fed to
steers.
Rations
Parameter Hay 2 3 4 5 LSD
DM intake, kg/day iT? 7.7b 7.8b 7.2b 7.8b 1.6
DM digestibility, percent 51.2
DM digestibility : hay
+ concentrate - 55.3 53.3 52.8 53.3
DM digestibility : concentrates
alone - 62. 3a 56. 9b 55. 5b 57. 3b 4.7
Numbers in a row with different superscripts differ
significantly (P < 0.05).
LSD = Least significant difference.
Table 3. Weight changes and percent fat in the carcasses of
finishing steers fed broiler litter-based rations.
Rations
Parameter Hay 2 3 4 5 LSD
Initial mean weight, kg 339.8 348.0 346.5 344.0 347.5
Final mean weight, kg 372.5 416.8 426.5 414.8 413.3
Average daily gain, g 297a 625b 727b 644b 598b 243
Mean fat percent 12.8 17.3 17.4 17.1 18.1
Numbers in a row with different superscripts differ
significantly (P < 0.05).
LSD = Least significant difference.
120
2. Use of fermented caged- layer waste in rations for bulling
heifers
Objective - To determine the extent to which caged- layer waste
(CLW) fermented with grain can replace conventional concentrate
diets based on sunflower seed cake (SSC) for growing heifers so
as to attain a target breeding weight of 260 kg.
Materials and Methods - CLW was fermented with ground sorghum
grain (Sorghum vulgare) in three percentage compositions on a
DM basis as follows :
Mixture A - 40% CLW and 60% grain
Mixture B - 60% CLW and 40% grain
Mixture C - 80% CLW and 20% grain
Sugarcane molasses was added to mixtures A, B and C to replace
10% of CLW dry-matter. Water was added to make up 40% of total
mixture (Caswell et al, 1974). The mixtures were allowed to
ferment in drums for at least 30 days before feeding to three
groups of animals each consisting of four Boran/East African
Shorthorn Zebu (EASZ) x Hereford crossbred heifers averaging
230 kg. A fourth group received a commercial - type ration
compounded with 68.4% ground sorghum grain and 31.6% SSC. The
fifth group was a negative control and received 1 kg DM of
Chl or is gayana hay.
All the five groups were grazed together. Groups 1 - 4
were supplemented with the four diets, in the evenings, at the
rate of 2.5 kg/animal/day plus a basal ration of 1 kg/day of
grass hay for 84 days. Intake and digestibility of each ration
were determined using three steers in metabolism sta'Is.
121
Results - The fermented mixture containing 60% CLW and 40%
grain had a DM digestibility of 61.6% and gave ADG value of 431
g (Tables 4 & 5). These figures compared favourably with a
digestibility of 62.3% (Table 2) and ADG of 494 g using a
commercial -type diet based on SSC and grain. Dry-matter intake
of the mixture containing 80% CLW was reduced significantly
(P<0.05) resulting in a low ADG (P<0.01). Details of this
trial are given by Odhuba et a I (1986b).
Table 4. Mean DM intake and digestibility of caged-layer
waste fermented with sorghum grain fed to steers.
Rations
Parameter Hay ABC S.E.D.
DM intake, kg/day 6.0 8.8 8.7 8.0 0.3
DM digestibility, percent
DM digestibility - hay +
concentrate - 56.9 57.0 55.4 2.3
DM digest ibi lity-
concentrate alone 61.3 61.6 56.9 4.2
Numbers in a row with different superscripts differ significantly
(P < 0.05).
S.E.D. = Standard error of difference between any two means.
6.0a 8.8b 8.7b 8.0C
55.0
-
.
122
Table 5. Liveweight (kg) and daily gain of growing beef heifers
fed rations containing fermented caged- layer waste
and grain.
Rations
Parameter Hay Commercial ABC S.E.D
Initial mean weight 229.3 234.3 232.3 231.3 230.0
Final mean weight 229.0 275.8 265.0 267.5 242.3
Average daily gain, g -3.6a 494. 0b 386. 9b 431. 0b 146. 4C 48.6
Numbers in row with different superscripts differ significantly
<P < 0.05).
3. Use of layers-deep litter ensiled with sorghum forage for
growing steers
Objective - To improve quality and characterise response of
feeding sorghum forage ensiled with layers-deep litter.
Materials and Methods - Layers-deep litter was ensiled with
sorghum forage (Variety 1291) to contribute 40% of total DM of
the mixture. Sugarcane molasses was added to make up 3% of the
mixture. Fermentation was allowed to continue for three
months. Twenty five Friesian/Ayrshi re x Boran/EASZ yearling
steers were divided into five groups balanced for breed and
initial weight. The animals were grazed on low quality dry
season Chl or is gayana pasture and were supplemented in the
evenings with the following diets:
1. Chopped Chl or is gayana hay ad I ibi tum (negative control)
2. Untreated sorghum silage alone
123
3. Untreated sorghum silage + 1.0 kg DM cottonseed cake (CSC)
and 1.0 kg maize meal (feedlot system, positive control)
4. Treated sorghum silage alone
5. Treated sorghum silage + 1.0 kg DM of maize meal
The total daily DM intake of treated and untreated
silage, with or without concentrate, and including grazing, for
steers weighing from 200 kg to 250 kg ranged from 5.1 kg to 7.6
kg. Grazing was estimated to provide approximately 2 kg
DM/day. The trial lasted for 70 days.
Results - Crude protein improved from 6.5%'in untreated silage
to 12. 2% in the treated silage. Animals that were fed treated
silage plus 1.0 kg maize meal gained 0.98 kg/day which was not
statistically different from AOG of 1.10 kg for the steers on a
commercial- type feedlot diet (Table 6).
Table 6. Liveweight and average gain (kg) of growing steers
supplemented with sorghum forage ensiled with layers
deep litter.
Rations
Parameter 1 2 3 4 5 S.E.D
Initial mean weight
Final mean weight
Average daily gain
231.4
262.0
0.448
224.
283,
.0
.2
.85b
226.4
301.8
1.10C
243.6
304.2
0.87b
231.4
299.8
0.
0.98bc 0.09
abeMeans followed by different superscripts are significantly
different (P<0.05).
S.E.D. = Standard error of difference between two means.
124
It would appear that untreated silage was near adequate
in meeting the nutrient requirements of the animals, hence the
marginal response to additional nitrogen and energy in the
treated silage (Fig. 1). However, there was a noticeable trend
towards improved growth rate when energy was added to treated
silage. It would be of interest to evaluate these diets with
more productive and demanding type of cattle such as lactating
cows.
4. Broiler litter in dairy rations
Materials and Methods - The composition of the rations fed to
milking cows is summarised in Table 7. The animals comprised
Friesian and Ayrshire cows, pure or crossbred. Three animals
were allocated to each of the three supplemental diets in a 3 x
3 latin square design. There were four replications in all.
Each animal received 1 kg DM of the compounded concentrates
(diets R0, R50 or R100) per 2 kg milk produced. Therefore DM
intake of the concentrates ranged from 5-6 kg per cow per day.
The quantities of feed provided (Table 7) were estimated
according to Anon (1975) to provide 12 MJ of metabol isable
energy per kg DM intake, being the amount of energy required by
a 450 kg dairy cow producing 15 kg of milk/day. The trial
lasted 9 weeks.
125
Figure1.Thepatt nofliveweightga nofste rsfedsorghumf r gensilwithpoul rylitte .
X—
-XChoppedgrasshay
_«Untreatedsil ge
-4Untreatedsil ge+e dcakema z
Treatedsilage
.—Treatedsilage+maiz
 
3456
Feedingperiodinw eks
10
Table 7. Composition (%DM) of broiler litter-based dairy
rations.
„ "■■'■ ■■-■'
Diets
Ingredients RO R50 R100
18.1 15.6 12.3 %Crude protein
Maize meal 42.00 42.00 42.00
Barley 15.00 15.00 15.00
Wheat bran 9.00 9.00 9.00
Sunflower seed cake 4.50 2.25 -
Rapeseed 9.20 4.60 -
Cottonseed cake 8.20 4.10 -
Sweet lupins 10.10 5.05 -
Broiler litter - 14.40 28.80
Molasses - 1.60 3.20
Minerals 2.00 2.00 2.00
Total % 100 100 100
R0 - Commercial protein concentrates only.
R50 - ration compounded to replace 50% of commercial protein
source.
R100- ration compounded to replace 100% of commercial protein
sources.
Results - The ration in which broiler litter completely
replaced the conventional protein sources was able to support
10.2 kg of milk/day compared to 11.6 kg/day from cows fed diets
compounded from commercial protein sources (Table 8). Although
this difference was significant (P<0.05), the cost of feeding
127
commercial protein supplements would tip the balance in favour
of the poultry- based diet. DM intake and milk butterfat were
not affected by feeding broiler litter. Similar results have
been reported by Kayongo and Irungu (1986) at Naivasha using
lactating Friesian heifers.
Table 8. Performance of cows fed concentrates containing
different levels of broiler litter.
Diets
Item R0 R50 R100 P
Milk yield, kg/day 11. 6a 10. 7b 10. 2b *
Milk butterfat, percent 4.0a 3.7a 3.9a NS
_Fj
Means on the same row followed by different superscripts are
significantly different at the level shown.
* Significant at P< 0.05.
CONCLUSIONS
1. Dry season supplementation with energy and protein sources
was beneficial to beef cattle grazing predominantly Rhodes
grass planted pasture.
2. Poultry waste used in compounding rations for cattle should
be dried in si tu or ensiled to render it safe for use by the
animals.
3. Sunflower seed cake can be replaced completely by broiler
litter to constitute 30% of finishing rations for steers
on a semi - intensive system as long as the animals are
supplied with some grain and molasses.
128
4. Crossbred heifers could be fed for a period of three months
prior to mating on a fermented 60:40 poultry layer
waste/ground grain ration to attain a breeding weight of
around 260 kg by 18 months of age.
5. Ensiling sorghum forage with poultry waste improved crude
protein content of the silage almost twofold. Ensiling
should be done with poultry waste and molasses making up 40
and 3 percent of total dry-matter of the mixture,
respectively. Such silages should be fed with a grain
supplement for optimal production.
6. Rations constituted with 30% of the concentrate mixture DM
as poultry waste can support about 10 kg of milk/day. Such
rations must be fortified with energy sources. It would
appear that CP levels of 12% in concentrate mixtures may, in
fact, be adequate for low to mediocre producing dairy
cattle.
7. The ubiquitous distribution of poultry farms in Kenya, both
small-scale and large enterprises, make poultry waste a
readily available source for compounding relatively cheap
cattle feeds of high quality.
REFERENCES
Alexander, D.C.; Carrire, J.A.J, and McKay, K.A. 1968.
acteriological studies of poultry litter fed to
livestock. Can. Vet. J. 9: 127-131.
Anon. 1975. Energy allowance and feeding systems for ruminants.
Tech. Bull. 33, Ministry of Agriculture, Fisheries and
Food; Department of Agriculture and Fisheries for
Scotland, Her Majesty's Stationery Office, London.
129
ARC (Agricultural Research Council). 1980. The nutrient
requirements of ruminant livestock. Commonwealth
Agricultural Bureaux, Farnham Royal, U.K.
Bhattacharya, A.N. and Fontenot, J. P. 1966. Protein and energy
value of peanut hull and woodshaving poultry litter. J.
Anim. Sci. 25: 367-371.
Bhattacharya, A.N. and Taylor, J.C. 1975. Recycling of animal
waste as a feedstuff. A review. J. Anim. Sci. 41: 1438-
1457.
Bugarski, D . ; Milanovic, A. Dzinic, M. and Beganovic, A. 1980.
(Nutritive and hygienic characteristics of silages made
by mixing broiler litter and maize plants). Nutr.
Abstr. 4790, p. 546.
Caswell, L.F.; Fontenot, J. P. and Webb, K.E. Jr. 1974.
Fermentation of ensiled broiler litter. Cited by Fontenot
and Webb 1975.
Caswell, L.F.; Fontenot, J. P. and Webb, K.E. Jr. 1975. Effect
of processing method on pasteurization and nitrogen
components of broiler litter and on nitrogen
utilisation by sheep. J. Anim. Sci. 40: 750-759.
Caswell, L.F.; Webb, K.E. Jr. and Fontenot, J. P. 1977.
Fermentation, nitrogen utilisation, digestibility and
palatability of broiler litter ensiled with high moisture
corn grain. J. Anim. Sci. 44: 803-813.
Fianu, F.K.; Assoku, R.K.G. and Palomeras, I.M.I. 1984a.
Poultry manure as feedstuff for ruminants. I. Effect of
air-drying oven-heating and autoclaving on odour,
pathogens and nutrient losses. Bull. Anim. Hlth.
Prod. Afr. 32: 143-148.
Fianu, F.K.; Assoku, R.K.G. and Hinson, F. 1984b. Poultry
manure as a feedstuff for ruminants. II. Effects of
ensilage on pathogens, nutrients and odour of diets based
on caged layer excreta. Bull. Anim. Hlth. Prod. Afr. 32:
350-354.
130
Fontenot, J. P. and Jurubescu, V. 1980. 31. Processing of
animal waste by feeding to ruminants. Proc. Symp.
Metabolism in Ruminants, France. pp. 641-662.
Fontenot, J. P. and Webb, K.E. Jr. 1975. Health apects of
recycling animal wastes by feeding. J. Anim. Sci. 40:
1267-1277.
Harmon, B.W. Fontenot, J. P. and Webb, K.E. Jr., 1972.
Performance studies with rations containing broiler
litter and molasses. Cited by Bhattacharya and Taylor
(1975).
Harmon, B.W.; Fontenot, J. P. and Webb, K.E. Jr. 1975. Ensiled
broiler litter and corn forage. I. Fermentation
characteristics. J. Anim. Sci. 40:- 144-155.
Johnson, R.R.; McClure, K.E.; Klosterman, E.W. and Johnson,
L.J. 1967. Corn plant maturity. III. Distribution of
nitrogen in corn silage treated with limestone, urea and
diammonium phosphate. J. Anim. Sci. 26: 394-399.
Kayongo, S.B. and Irungu, K.R.G. 1986. Evaluation of broiler
waste in formulation of concentrate for lactating
Friesian heifers grazing irrigated pasture. E. Afr.
Agric. For. J. 52: (1):9-15.
Ledger, H.P.; Gi liver, B. and Robb, J.M. 1973. An examination
of sample joint dissection and specific gravity technique
for assessing the carcass composition of steers
slaughtered in commercial abattoirs. J. Agric. Sci.
Camb. 80: 381-392.
Odhuba, E.K.; Magadi, J. P. and Sanda, I. A. 1986a. Poultry
waste in cattle rations. I. Utilisation of broiler
litter as a source of nitrogen in semi - intensive
feedlot rations. E. Afri. Agric. For. J. 52: 16-21.
Odhuba, E.K.; Magadi, J. P. and Sanda, I. A. 1986b. Poultry
waste in cattle rations. II. Use of fermented caged
layer waste in rations for growing heifers. E. Afr.
Agric. For. J. 52: 22-36.
131
Shah, S. I. and Muller, Z.O. 1983. Feeding animal wastes to
ruminants. In: By-product utilization for animal
production. Proceedings of a workshop on applied
research held in Nairobi, Kenya, 26-30 September 1982.
IDRC, Ottawa. pp. 49-57.
Smith, O.B.; Macleod, G.K; Mowat, D.N. and Moran, E.T. 1979.
Effect of feeding organic acid treated hen excreta upon
performance, carcass merit and health of feed- lot cattle.
J. Anim. Sci. 49 (5) : 1 183- 1 189.
Smith, L.W. and Wheeler, W.E. 1979. Nutritional and economic
value of animal excreta. J. Anim. Sci. 48: 144-156.
132
TEPHROSIA SPP AND COTTONSEED (GOSSYPIUM SPP) CAKE SUPPLEMENTATION
OF RICE AND MAIZE STALKS FED TO SHEEP AND GOATS IN THE DRY SEASON
R.T. Fomunyam and S.E. Mbomi
Institute of Animal Research
Mankon, Bamenda
Cameroon
ABSTRACT
Tephrosia spp. . a legume grown locally in Cameroon, and
cottonseed cake, a by-product obtained from processing of
cotton were used to supplement maize and rice stalk diets fed
to sheep and goats in the dry season. There were 6 diets fed
to 12 Dwarf forest sheep and 12 West African Dwarf goats. A
2x6 factorial design was used for the analysis. This
supplementation increased the efficiency of utilization of the
crop residues by the ruminants. There was a higher intake,
weight gain and low mortalities for sheep than goats. There
were high mortalities for goats but those which survived had
intake above maintenance level. Diets supplemented with 50%
Tephrosia and 50% cottonseed cake had the best results in terms
of intake, weight gain and percent mortalities.
Apparent digestibility values for crude protein was
quite high and similar for all the diets. Therefore Tephrosia
can equally be utilized like cottonseed cake for protein
supplementation in adult sheep as no mortalities were observed.
Apparent dry-matter digestibility values were high for
the control checks indicating better palatability and therefore
high intake. More work should be done on this study to find
out the appropriate levels and the combinations needed for
protein supplementation using the above supplements so as to
improve on the intake of agricultural by-products and to
encourage the use of Tephrosia which can also be used for fuel
and maintaining soil fertility.
133
INTRODUCTION
A major constraint facing livestock development in Cameroon is
the lack of adequate supplies of feedstuffs at economic prices.
Feeds represent the greatest proportional cost in livestock
production and its availability is affected by seasonal
variation in feed quantity and quality which causes
fluctuations in animal nutrition and productivity throughout
the year.
There is competition between livestock and humans for
the available protein feedstuffs.
Increasing land pressure and the resultant restriction
of livestock to marginal lands has resulted in the need to
supplement the animals that graze these lands. This problem is
further aggravated by the rampant deforestation that is going
on to divert lands to food crop production.
To increase animal production, recent stress has been on
the utilization of agricultural by-products in animal feeding.
Despite the availability of these by-products in great
quantities and their potentials as substantial feed sources,
they are lowly utilised due to their low protein levels which
makes them less palatable. This can however be overcome by
supplementing the diets with locally produced cheap protein
sources.
This paper considers the feeding of Tephrosia species, a
cheap locally produced legume and cottonseed cake, a by-product
from processing of cotton to overcome the constraint to the
efficient utilization of rice and maize stalks fed to sheep and
goats in the dry season when feed is in short supply.
Tephrosia species can also be used in alley cropping to
improve soil fertility, prevent soil erosion and conserve
moisture thereby increasing the yield of crops. At the end of
the cropping season, Tephrosia leaves can be used for protein
supplementation and the stalks for firewood. Propagation of
134
Tephrosia species is by seeds which are abundant, therefore
planting can easily be done by local farmers. Very little
literature is known to the authors about the feeding of
Tephrosia to small ruminants, although it is known to contain
Rotenone, an insecticide and fish poison (National Academy of
Science, 1979).. In Cameroon, it is a big relish to cattle
feeding; thus the study of its potentials as a protein
supplement to small ruminant nutrition was necessary.
MATERIALS AND METHODS
In the first trial 12 Dwarf forest and 12 West African Dwarf
goats (average age 6 months) with an initial weight of 9.4 kg -
10.2 kg were fed six diets namely :
1) 70% maize stover + 18% Tephrosia + 10% molasses + 2%
bone meal
2) 70% maize stover ♦ 18% cottonseed cake + 10% molasses
+ 2% bone meal
3) 70% rice straw + 18% Tephrosia + 10% molasses + 2%
bone meal
4) 70% rice straw + 18% cottonseed cake + 10% molasses +
2% bone meal
5) 70% maize stover + 9% cottonseed cake + 9% Tephrosia
+ 10% Molasses + 2% bone meal
6) 70% rice straw + 9% cottonseed cake + 9% Tephrosia +
10% molasses + 2% bone meal.
Maize and rice stalks were harvested 3 months post-
harvest and hand-chopped into 3 cm pieces and stored in jute
bags. Tephrosia species was also harvested and dried on black
polythene sheets and also stored in jute bags. Molasses was
added to maize stalks or rice straw and fed separately while
protein supplement was fed twice at 8 am and 2 pm each day.
All animals had free access to water and salt licks.
135
The design was a 6x2 factorial consisting of 6 diets and
two species of animals. The following parameters were
determined, weight gain, feed intake, and percent mortalities.
The study was conducted for 5 months. Data collected was
subjected to statistical analysis (Steel and Torrie, 1980).
In the second trial, 24 adult Dwarf forest sheep
(average age 2 years) with a weight range of 16 kg - 35 kg were
used to test the apparent digestibility of maize stover and
rice straw diets supplemented with Tephrosia species and
cottonseed cake. The plan of feeding was 10 days of
adaptability and seven days of total collections. The animals
were fed the following diets:
1) 70% maize stover + 28% Tephrosia + 2% bone meal
2) 70% maize stover + 28% cottonseed cake + 2% bone
meal
3) 70% rice straw + 28% Tephrosia + 2% bone meal
4) 70% rice straw + 28% cottonseed cake + 2% bone meal
5) 70% Pennisetum purpureum + 28% Tephrosia + bone meal
6) 70% Pennisetum purpureum + 28% cottonseed cake + 2%
bone meal
7) 70% Tripsacum laxum + 28% Tephrosia + 2% bone meal
8) 70% Tripsacum laxum + 28% cottonseed cake + 2% bone
meal
These animals also had access to water and salt licks.
Table 1 shows the chemical composition of feedstuffs
used in these trials. Tripsacum laxum and Pennisetum purpureum
were included as control checks,
136
Table 1. Percent chemical composition of feedstuffs used in
test diets.
Characteristics
Feed items
Dry Crude Crude Ash Ether
matter protein fibre extract
Maize stover 91.1 5.3 33.1 7.1 2.1
Rice straw 94.9 1.6 61.8 17.5 1.6
Tephrosia 91.3 15.4 25.6 5.4 2.6
Cottonseed cake 94.5 45.5 5.9 7.1 6.7
Elephant grass
(Pennisetum
purpureum) 96.0 5.3 3.2
Guatemala grass
(Tripsacum
laxum) 95.8 7.6 3.9
RESULTS
Table 2 shows that there was no significant (P<0.05) difference
intake g/OM/day between animal species and between diets.
However, values for goats averaged 404.3 g and for sheep 465 g.
All animals fed rice straw and Tephrosia died between the
second month and third month of the experiment while goats
feeding maize stover and Tephrosia died during the second month
of the experiment.
137
Table 2. Feed intake, weight gain and percent mortalities of
sheep and goats fed rice and maize stalk/cottonseed
cake and Tephrosia species.
a> ,
L Maizestover+ 1
1
1
1
-1+ o1
Ricestraw
+Cottonseed Maizestover
1 Ol 03
. O 00
1 00 S-
Ricestraw +Tephrosia
Tephrosia+ 3C + J
Parameters Breed!
Sheep
Cottonseed
cake
Cottonseed
cake
<T3 ro OJ,
J-— <d + SEM
4J CO UV ~
CO O El
| HI CL s- ol
cux: +j., N QJ
;i
i
<J QL+->
•r- <u o'
oil- <_>|
Feed intake |379 1 498 1 286 | 570
| 112 | 570
1 1
i 528 1 529 |
g DM/animal Goat
Sheep
| 216 | 507
1
i 501 | 520 | 1.34
J i I I
Dai ly weight i hi 114.3 | 40
I 7.1 | 31
I I
i 43 1
30 |
47 1
gain g/ animal Goat |7.1 1 33 i 35 | 1.95
I .1 i. 1 I
Sheep 1 o 1 oJ. loo x P. i 0 1
50 |
o 1
% mortality Goat 1 100 1 50 | 100 | 0 i o 1
Weight gain values varied between 33-35 g/day for goats
and 40-47 g/day for sheep suggesting the levels fed were
probably only adequate for maintenance.
Table 3 shows values for apparent digestibility. Values
for crude protein were quite similar while those for dry-matter
varied.
DISCUSSION
Feed intake for sheep and goats were in the range 3 - 3.7% of
body weight indicating that the diets were palatable. Intake
of dry-matter for goat meat should not exceed 3% of liveweight
for any extended period of time (Devendra, 1980). However, the
low weight gains showed poor efficiency of utilization which
may be due to the use of stale maize stover ten months after it
was harvested.
138
Table 3. Apparent digestibility (%) of the test diets fed to
sheep.
Parameters
Dry matter
(%)
Crude
protein
(%)
i- -o
0) 0)
MOO)
•t- O -*
51
74.1
o ro
+-> • 1—
l/) to
o
e s-
N -E
•r— Q.90 QJ
s; h-
54
67.0
"O
I* 0)a>
fO </5!*- C"
'-4-> o
1 M +->
.<u o 0)
uu-^|
to >
r + U I
i 63
60 |
3|
■2
•r-
al 1/1
S- O1
4-> s-1
V) .c.
Q.'
O) aj
a;'
aiai a q
Ol— ;P -i-
r- 31 S-
Ql + CLj I— 1—
_
^
59 I 85
56.3 I 63.8
I
85
59.8
M4-> ■**
O fO
QJCJ U
84
72.3
80
72.5
Percent mortality showed that all goats fed maize stover
and Tephrosia and all sheep and goats fed rice straw and
Tephrosia died. The cause was not known. However, Tephrosia
contains an insecticide Rotenone (National Academy of Science,
1979) which is a fish poison. This must have been toxic to the
young growing animals which cannot tolerate the level present
in their diets.
However, there were no mortalities when Tephrosia was
fed to adult animals in the digestibility trials. Diets of
maize stover or rice straw, supplemented with equal amounts of
Tephrosia and cottonseed cake were the best diets with high
intake, high weight gain and low mortalities.
For the apparent digestibility we found out that the
crude protein utilization was quite high and similar for all
the diets. There was a high dry-matter digestibility for
Pennisetum purpureum and Tripsacum laxum than for maize and
rice stalks. This might be due to better palatability and
therefore high intake. Cottonseed cake did as well to
supplement the by-products as Tephrosia. However, more
139
mortalities were observed with young growing animals feeding
Tephrosia.
Postmortem examination of dead animals showed that they
died of either gastro-enteri tis, pneumonia or starvation.
CONCLUSION
From the results, it appears that young growing sheep and goats
can tolerate Tephrosia as a protein supplement only to a
certain level which has to be studied by doing more work.
However, adult sheep can tolerate Tephrosia as a protein
supplement as no mortalities were observed. The most
appropriate protein supplementation was a combination of 50%
Tephrosia + 50% cottonseed cake together with the agricultural
by-product (rice or maize stalks). This was able to maintain
the animals with few mortalities. More work should be done on
Tephrosia species as it has a lot of potential for both
livestock and in the crop farming systems.
Tephrosia species and cottonseed cake can equally be
used for protein supplementation as both have high and similar
crude protein digestibility values. The major limitations to
the use of rice and maize stalks in this study was low intake
due to the diets not being palatable. This constraint can,
however, be overcome by supplementing these diets as was done
in this study using Tephrosia and cottonseed cake.
REFERENCES
Devendra, C. and Marca B. 1970. Goat production in the tropics.
Commonwealth Agricultural Bureaux, Farnham Royal, UK.
182 pp.
Devendra, C. and "Mcleroy, G.B. 1982. Goat and sheep production
in the tropics. Intern. Tropical Agricultural Series,
Longman, London and New York. pp. 55-72.
Le Houerou, H.N. 1980. Chemical composition and nutritive
value of browse in tropical West Africa. Proc.
Intern. Symp. on Browse in Africa, Addis Ababa, 8-12
April. ILCA, Addis Ababa.
140
Little, M.T. and Hills, F.J. 1978. Agricultural
experimentation. Design and analysis. John Wiley and
Sons, New York, Chichester, Brisbane and Toronto. 350 pp.
Mackenzie, D. 1970. Goat husbandry. Faber and Faber, London.
pp. 137-169.
NAS (National Academy of Science). 1980. Tropical legumes.
Resources for the future. National Academy of Science,
Washington, D.C. 332 pp.
Oyenuga, V.A. 1968. Nigerian foods and feeding stuffs. Ibadan
University Press, Ibadan, Nigeria. pp. 60.
Steel, R.G.D. and Torrie, J.H. 1980. Principles and procedures
of statistics. McGraw-Hill Book Company, N.Y.
Zemmelink, G; Tolkamp, B.J.; and Meinderts, J.H. 1985. Feed
intake and weight gain of West African Dwarf goats. In:
J.E. Sumberg and K. Cassaday (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, Addis Ababa, Ethiopia. pp. 29-33.
141
THE POTENTIAL OF CROP RESIDUES, PARTICULARLY WHEAT STRAW, AS
LIVESTOCK FEED IN ETHIOPIA
Lulseged Gebrehiwot and Jamal Mohammed
Institute of Agricultural Research
P.O.Box 2003, Addis Ababa, Ethiopia
ABSTRACT
Crop and livestock production are important activities in the
smallholder mixed farming systems in Ethiopia. Feed resources
for livestock are natural herbage and crop residues. Cereal
straws of teff (Eragrostis tef ) . barley, wheat and pulse crop
residues are very important particularly during the dry season.
Currently crop residues are used as is with no treatment to
improve intake and digestibility. The quality and quantity of
residues produced is also very low in relation to the total
area of cropped land.
Results of experiments clearly indicate that the yield
and quality of crop residues could be tremendously improved
through agronomic practices and varietal selection.
Undersowing of wheat with forage crops did not reduce grain
yield but resulted in reasonable production of straw and
undersown forages which could improve intake and digestibility
of the residue. In the wheat improvement programme,
significant variations were found among the varieties with
respect to grain yield, straw yield and quality. There seems
to be a wide range of possibilities to improve the production
and utilisation of wheat straws, and crop residues in general.
Breeders and agronomists need to consider the residue aspect as
part of the overall crop improvement programme.
INTRODUCTION
Ethiopia is an agricultural country with a diverse climate
varying from cool tropical highlands to arid lowlands. Though
low in productivity it has the highest number of livestock in
sub-Saharan Africa. Among other factors, feed shortage, both
142
in quantity and quality, is a major constraint for the
development of the livestock industry in Ethiopia.
At present two broad categories of livestock production
systems are recognised in the country. In the pastoral areas,
which are characterised by low and erratic rainfall, livestock
are mainly kept for milk and to some extent for meat. They
provide the sole means of subsistence for the nomadic
pastoral ists. It is estimated that some 25% of the total
Ethiopian livestock population is found in this region. These
animals depend entirely on the natural vegetation to satisfy
their nutritional requirements.
The highlands of Ethiopia have more favourable climate;
both for crop and livestock production. Over 70% of the human
as well as the livestock population reside in this region.
Small holder mixed farming is the dominant mode of production
in the Ethiopian highlands. Major food crops grown are teff
(Eragrostis tef ) . barley, wheat and pulses; and in the warmer
regions maize and sorghum. The most important contribution of
livestock to agricultural production in the Ethiopian highlands
is the use of oxen for cultivation. Crops and livestock are
closely integrated throughout the highlands in a complex of
competitive and complementary ways (Gryseels and Anderson,
1983).
Livestock in the highland peasant farming system get
their feed from natural herbage and crop residues. Cereal
straws of teff, barley, wheat and pulse crop residues are
stacked after threshing and fed to selected group of animals
during the dry season. Livestock also have access to crop
stubbles and weedy fallows. It is estimated that crop residues
and aftermath grazing contribute 10% of the annual feed demand
(FAO, 1981).
Crop residues have long been important as a maintenance
feed for ruminants. However, when used alone, they are of very
low feeding value with poor metabol isable energy, negligible
available protein, and seriously deficient in mineral and
vitamins (Staniforth, 1979). On the other hand, crop residues
143
vary greatly in chemical composition and digestibility
depending on varietal differences (Reed et al, 1986) and
agronomic practices (Staniforth, 1979). Their feeding value
and intake can also be greatly improved through treatments and
supplementation with protein and energy-rich feeds (Butterworth
et al, 1986, Olayiwole et al, 1986).
Developing countries like Ethiopia need to seriously
consider improving the quantity and quality of crop residues
produced by the smallholders. Varietal effects on the quantity
and nutritive value of cereal and pulse crop residues have not
received enough attention. Understandably because the major
efforts have been on increasing food production only. These
programmes should consider the residues as part of the overall
improvement programmes.
This paper attempts to review the extent and use of crop
residues in Ethiopia; mainly in the highlands. It places
special emphasis on wheat with respect to varietal differences
and agronomic practices to enhance the utilisation of the
straws.
Extent of crop production and available residue
Estimates of the Ethiopian Central Statistics Office show that
during the period of 1975 to 1978, on the average, annually
about 5 million hectares of land were put under cereals and
pulses. Mean grain yield for the same period was 970 kg and
810 kg/ha for creals and pulses respectively. However, during
the period 1979 to 1982, the total area cultivated for cereals
and pulses increased to 5.6 million hectares (Central
Statistical Office, 1984). Respective grain yields also
increased to 1240 kg 1140 kg/ha (Table 1).
As the area of crop production is increased, the size of
grazing areas dwindles, exacerbating the problem of feed
shortage. In this situation one could only cope with the
problem by improving the quantity and quality of crop residues
produced. FAO estimates indicate that in 1979/80, Ethiopia as
a whole produced about 6.3 million tonnes of cereal straws,
144
stovers and pulse residues (FAO, 1981). The figure seems to be
low when compared with the total acreage under production.
However, there are still wide options to improve total
production.
Table 1. Estimated area and yield of major crops in Ethiopia.
Major Crops 1975/76 to 78/79 1979/80 to 82/83
(4 years mean) (4 years mean)
hectares kq/ha hectares kg/ha
Teff 1,368,500 750 1,401,600 920
Barley 722,800 980 864,800 1220
Wheat 522,300 960 605,400 1140
Maize 791,200 1360 769,600 1700
Sorghum 753,500 1000 1,013,800 1490
Faba bean 277,900 1020 340,600 1490
Field peas 121,900 650 176,300 950
Haricot beans 33,300 780 26,900 910
Cereals total 4,420,300 970 4,848,300 1240
Pulses total 643,000 810 795,300 1140
Source: Central Statistical Office (1975 to 1983).
Variability of crop residues in yield and quality
The quantity and quality of residues produced by various crops
vary greatly depending on crop species. Wheat and barley
usually give high straw yields but of inferior quality. Among
the cereals teff straw is relatively the best and is comparable
to a good natural pasture hay. Pulses residues, though low in
yield, are of high quality (Table 2). The quality and yield of
the various crop residues shown in Table 2 could vary depending
on agronomic practices and environmental conditions. However,
the figures give good indications of the relative importance of
the various crop residues.
145
Table 2. Yield and chemical composition of various crop
residues on dry-matter basis.
Percent
Residue type Yield DM EE Ash CP NDF
kg/ha
Barley straw 10,000 92.6 2.3 8.4 4.7 71.5
Teff straw 5000 92..6 1 .9 8.4 5.2 72.6
Wheat straw 9000 93..1 1 .2 9.0 3.9 79.8
Faba bean residue 3800 91..7 0 .8 10.4 7.2 74.3
Field peas residue 5000 91..9 1 .2 6.1 6.7 73.6
Natural pasture hay 4100 92,.2 1 .5 9.5 6.6 73.8
DM = dry matter; CP = crude protein;
EE = ether extract; NDF = neutral -detergent fiber.
The performance of animals on residue diets is also
known to vary depending on crop species. Table 3 shows the
weight gains of steers fed for 116 days a ration composed of
50% residue, 20% molasses, 25% noug cake (Guizotia abyss inica) .
4% bone meal and 1% salt (IAR, 1976). As shown in Table 3
wheat straw was the poorest roughage and teff straw the best.
Dry-matter intake and daily weight gain were lowest for wheat
straw, 5.0 kg and 352 gm/head respectively.
146
Table 3. Weight gains of steers fed crop residue based diets
at Holetta (1974/75) for 116 days.
Roughage source
Parameters considered Teff
straw
Wheat
straw
Oats
hay
Native
hay
Initial weight (kg)
Final weight (kg)
Daily gain (g)
Daily feed intake (kg)
Feed/kg liveweight gain (kg)
186 185
258.8 225.9
628 352
6.9 5
11 14.2
182 184.3
231.9 239.6
430 477
5.5 5.9
12.8 12.4
* Rations consisted of 50% crop residue, 20% molasses, 25% noug
cake, 4% bone meal and 1% salt.
Source : IAR (1976).
Possibilities for improving the yield, quality and utilisation
of wheat straw
a) Agronomic practices
The grain yield of cereals and pulses is highly influenced by
various agronomic practices. Since high grain yield is usually
a function of active vegetative growth, agronomic practices
which aim at increasing grain yields, do result in higher
yields of residue.
A fertiliser trial was carried out on irrigated wheat in
the Awash Valley, a fertile alluvial soil. Though the various
rates of nitrogen fertilisation had very little effect on grain
production (Table 4), straw yield and quality were
significantly improved. Applying 46 kg N/ha improved leaf-to-
stem ratio, and % N in the leaves and stems by 20, 47 and 21%
respectively over the control. With more N application there
was more influence on leaf-to-stem ratio and N composition of
the plant. In Ethiopia, farmers who harvest good grain crops
usually have more residues to feed their cattle during the dry
season. Nowadays farmers are encouraged to use fertilisers,
147
especially in areas where rainfall is more reliable. This
practice will hopefully result in more crop residues and grain
yields.
b) Undersowing of forage crops to wheat
Studies by the Institute of Agricultural Research in Ethiopia
show that forage crops could be successfully established
under cereals. The effect of the undersown forage crops on
the grain yield of the cereals varied depending on crop
species and the level of weed management. When maize was
undersown after second weeding (about six weeks after
planting) the grain yield was not affected at all. But in the
case of wheat, where the forage crops were sown at the same
time with the wheat the grain yield was reduced by about 20%
(Lulseged et al, 1987).
Table 4. Effect of N fertilization on grain yield and on
quantity and quality of wheat straw in the Awash Valley.
Mean for 1985 and 1986
Fertilizer rate
Grain yield Straw yield Leaf/stem %N %N
ratio leaves stems
N kg/ha ..kg/h
0 3500 7900 0.83 0.38 0.17
46 3800 8600 1.00 0.46 0.25
69 3800 9100 1.02 0.57 0.30
92 4200 9200 1.07 0.63 0.34
115 4300 10400 1.16 0.65 0.34
LSD (0..05) NS 1.0 t/ha
The practice of undersowing cereals with forages has
particular relevance in the highlands of Ethiopia where
fallowing of cropped- land is common and feed shortage is a
148
serious problem. Table 5 shows results of an experiment at
Holetta where wheat was undersown with various forage crops.
The difference in grain yield of the wheat for the various
treatments was non-significant. The yield on the control plot
(sole crop of wheat) should probably have been higher than the
undersown plots. But because of excessive lodging the yield
was even lower than the other treatments.
Table 5. The performance of wheat and undersown forage crops at
Holetta (1982/83).
Undersown forage species
Wheat grain Wheat straw Forage
yield yield yield
(air dry) (dry matter)
kg/ha
Control (wheat only) 2040
Phalaris tuberosa cv Sirocco 2630
L o I i um perenne cv Kangaroo Valley 3410
L o I i um perenne cv Mt. Alma 2330
Lol ium perenne cv Barspectra 2760
Festuca arundinacea 3100
Setaria sphacelata cv Narok 2560
7900
9800 3100
11400 3500
8200 7000
7600 4000
11500 1300
9000 1900
19.8 15
NS 800 kg/ha
cv%
LSD (0.05)
17.8
NS
The most interesting part of this experiment was that on
the average 9400 kg/ha of wheat straw and 3400 kg/ha of
improved forages could be harvested from the same piece of
land. Similar experiments in Ginchi area (Vertisol, 2200 m
elevation) also showed various grasses and legumes could be
successfully established under wheat (Table 6) (IAR, 1982).
ILCA's investigations on farmers' fields at Holetta
indicated that undersowing native clovers namely Trif ol ium
tembense and T^ rueppel I ianum with 30 kg P/ha significantly
improved both wheat grain and straw yields. The increase over
the control (wheat alone) was 22 and 29% for grain and straw
yields respectively (Abate and Jutzi, 1985). Undoubtedly the
149
quality of the straw would be improved tremendously due to the
presence of the forage species, particularly the legumes.
Various investigators have reported that the digestibility and
intake of crop residues alone are very low and weight gains of
animals are minimal (O'Donovan, 1979; Reed et al, 1986).
However, when supplemented with improved forages, particulary
legumes, intake, digestibility and weight gains improved.
Hence, wherever the environmental and farming system conditions
permit, undersowing should be encouraged.
Table 6. Forage crops undersown to wheat, Ginchi, 1980/81.
Wheat Forage Forage
Treatment yield establ is hment yield
(kg/ha) Score 0- 5 (kg/ha)
Sole crop (control) 2930 - -
Alfalfa 2850 2 700
Barrel medic 3090 4 3200
Snail medic 2840 3 2100
Phalaris 3060 2 200
L I o I i um 1960 5 2600
Tall fescue 2900 2 700
Setaria 2790 2 400
CV 19% 0 = poor
LSD (0. 05) NS 5 = Excellent
c) The need to select for better grain and straw yielding
varieties
Classically, the objective of any crop improvement programme is
to raise the level of grain yields, with no consideration to
straw yield and quality. Under small peasant holding, however,
both the grains and straws are important. In Ethiopia over 90%
of the agricultural produce comes from the peasant sector.
Therefore in order to improve overall farm productivity and
income of the smallholders, development of crop varieties with
improved grain as well as straw yields is of paramount
importance.
150
In the wheat improvement programme for irrigated
lowlands, the selected varieties have been examined for grain
yield as well as straw yield and quality. Fourteen varieties
have been tested for three years in the Awash Valley. Of
these, eight gave grain yields of over 4000 kg/ha. Some of the
high-yielding varieties had low straw yields. Considering both
grain and straw yields the varieties PAI 4, Dashen, Gara and
Chenab 70 were the best with straw yields of 6300 to 7500 kg/ha
(Table 7). Though there were other varieties with straw yields
of nearly 8000 kg/ha, their grain yield was very low. The
varieties also showed great variability with respect to leaf-
to-stem ratio and % N in the leaves. Considering all these
factors together, Chenab 70 and Dashen seem to be the best in
terms of both grain and straw yield and quality.
CONCLUSION
In the Ethiopian highlands crop and livestock production are
complementary. Since most of the livestock in the highlands
are mainly kept for draught, the cultivation of more land
results in more crop residues to feed the work oxen and
selected group of animals. However, currently the quantity and
quality of residues produced are very low.
Therefore inorder to compensate for the grazing land, which has
been converted into crop land, agronomic practices and crop
improvement programmes need to consider the improvement of both
grain and straw yields and quality. Since there are strong
crop improvement programmes of the major cereals and pulses in
Ethiopia, there is a great chance of achieving success. The
utilisation of crop residues also needs to be enhanced through
the use of forage legumes and protein/energy-rich industrial
by-products.
151
Table 7. Grain yield, straw yield and quality of wheat
varieties tested in the Awash Valley (1985 to 1987).
Grain yield Straw yield Leaf-to-stem %N %N
(3 yrs mean) (2 yrs mean) ratio leaves stems
kg/ha.
MLKS 11 4300 5700 0.83 0.68 0.29
PAI 4 4200 6300 0.78 0.56 0.22
Dashen 4000 6900 1.08 0.79 0.32
Blue Jay 'S' 4200 5400 0.79 0.54 0.25
CM 5287 -N-2M 3600 5300 0.61 0.74 0.33
CM 30136-3Y-1Y 3500 5300 0.78 0.68 -
Gara 4200 7500 0.91 0.57 0.32
Quimori 3800 6100 0.65 0.65 0.24
Chenab 70 4400 7200 0.77 0.83 0.28
Galld-4R-Resel (B) 4200 5900 0.85 0.64 0.30
Monco x WW x LEE 4100 5600 0.96 0.66 0.29
Gall-YR-Resel (B) 3700 7800 0.95 0.61 0.24
Enkoy 3700 7800 0.68 0.58 0.35
Ani 'S' Cm 26346 3600 5800 0.50 0.59 0.24
CV% 15 20
LSD (0. 05) 0 .7 1.5
ACKNOWLEDGEMENTS
We are very grateful to Ato Addisse Nuramo and Ato Seyoum
Bediye for running the chemical analysis of the feed samples.
REFERENCES
Abate Tedla and Jutzi, S. 1985. Results of a cereal forage
legume intercropping trial on smallholder farms in the
Ethiopian highlands. Highlands Programme Report.
International Livestock Centre for Africa (ILCA),
Addis Ababa.
152
Butterworth, M.H. and Mosi, A.K. 1986. The voluntary intake
and digestibility of combinations of cereal crop
residues and legume hay for sheep. ILCA Bulletin 24:
14-17. International Livestock Centre for Africa,
Addis Ababa.
Central Statistical Office. 1984. Results of agricultural
sample surveys. 1974 to 1978 and 1979 to 1984.
Government of Ethiopia. Addis Ababa, Ethiopia.
FAO. 1981. International scheme for the co-ordination of Dairy
Development and International Meat Development Scheme.
Report of a Mission to Ethiopia, 27 May - 28 June,
1980. FAO, Rome.
Gryseels, G. and Anderson, F.M., 1983. Research on-farm and
livestock productivity in the central Ethiopian
highlands: Initial results, 1977 - 1980. ILCA Research
Report No. 4. International Livestock Centre for
Africa, Addis Ababa.
IAR (Institute of Agricultural Research). 1982. Animal Science
Forage and Range Management Department Progress Report.
April 1980 to March 1981. Addis Ababa, Ethiopia. pp.
73 - 76.
IAR (Institute of Agricultural Research). 1976. Results of
experiments in animal production. 1966/67 to 1975.
Animal Production Report No. 1. Institute of
Agricultural Research, Addis Ababa. p. 42.
Lulseged, G.; Gebremedhin, H. and Taddesse, T. 1987.
Undersowing of forage crops in cereals: Some
achievements. Proceedings of the First National
Livestock Improvement Conference, Addis Ababa, February
11 to 13, 1987. Institute of Agricultural Research, Addis
Ababa, Ethiopia.
O'Donovan, P.B. 1979. Fattening crossbred and Zebu cattle on
local feeds and by-products in Ethiopia. World Animal
Review 30: 23 - 29. (FAO, Rome.)
153
Olayiwole, M.B.; Butterworth, M.H.; Sayers, A.R. and Olorunju,
S.A.S. 1986. The effect of supplementing cereal straws
with urea, Trifolium hay and noug meal on feed intake
and liveweight gain of growing crossbred heifers.
ILCA Bulletin No. 24: 18-20. International Livestock
Centre for Africa, Addis Ababa. pp. 18-20.
Reed, J.D.; Abate Tedla and Jutzi, S. 1986. Large differences
in digestibility of crop residues from sorghum
varieties. ILCA Newsletter vol 5, no. 1.
Staniforth, A.R. 1979. Cereal straw. Clarendon Press, Oxford,
Great Britain.
154
DOLICHOS LABLAB (LABLAB PURPUREUS) IN BY-PRODUCT-
BASED DIETS FOR LACTATING COWS IN BOTSWANA
B. Kiflewahid and B. Mosimanyana
Animal Production Research Unit
P. Bag 0033, Gaborone, Botswana
ABSTRACT
Dairy cattle feeding was based on crop stovers supplemented
with Dolichos lablab (Lablab purpureus) and post-harvest
residues herein after referred to as lablab. Lablab was
introduced to 30 small-scale dairy farms. Average lablab dry-
matter yield from 30 farms farmers (ton/ha) for 0 and 100 kg/ha
single superphosphate (10.5%P) fertilizer rate were 1.23 and
1.44, respectively, but not different (P>.05). Average dry-
matter yield (ton/ha) at 0, 100 and 250 kg/ha rate, on-station,
were 1.41, 1.56 and 1.70, respectively, but not different
(P>.05). Phosphorus fertilization did not show significant
(P>.05) effect in dry-matter yield due to low seasonal rainfall
and distribution patterns in the project areas (262 to 414 mm
rainfall). Total quantities of lablab hay, sorghum/millet
stover and sorghum chaff/husks harvested by 30 farmers was
34.1, 56.4 and 7.2 tons dry-matter, respectively.
Sorghum and millet stover dry-matter yield (ton/ha), on-
farm, ranged from 0.66 to 1.74 and 0.78 to 1.00, respectively.
On-station dry-matter yield (ton/ha) ranged from 1.87 to 3.46
for different sorghum stover varieties. Dry-matter yield
(ton/ha) for millet, maize and cowpea stovers were 2.42, 3.04,
and 1.19, respectively.
The dry-matter and nutrient contribution of leaves, stems
and twines and roots to whole lablab, Tswana cowpea and ER-7
cowpea were assessed. Dry-matter contribution by leaves to
whole Tswana cowpeas (57.8%) were higher than lablab (47.0%)
and ER-7 cowpeas (57.8%) were higher than lablab (47.0%) and
ER-7 cowpeas (48.0%). Overall the total dry-matter and nutrient
contribution of leaves to whole plants was higher than stems
and twines in all three crops.
155
Average daily milk yield/cow/day (excluding milk left for
calf) for Simmental-Tswana crossbred and Tswana cows fed
sorghum stover based diets supplemented with either 15% lablab
(diet A) or 25% sorghum bran (Diet B) were 2.2 and 3.4; 1.4 and
1.6 kg/day, respectively. The results showed significant
differences (P<.05) between breeds but not within breeds fed
the different diets. Average lactation length (days) and milk
yield/cow/lactation (kg) for Simmental-Tswana and Tswana cows
were: 273 and 223; 760 and 338, respectively. Average birth
weight for Simmental-Tswana calves (34 kg) were greater than
for Tswana calves (28 kg).
INTRODUCTION
The major objective of the Small Scale Dairy Production Project
was to increase milk and milk products for both subsistence and
commercial use in the traditional communal farms of the
Gaborone region. The project covers six localities involving 30
farmers who participate fully in dairy production research.
In order to achieve optimal production objectives, a
technical and management package incorporating the approaches
and strategies related to baseline survey, animal feeding,
management inputs, breeding and health, fodder production and
utilization, milk marketing and extension linkages were
developed (APRU, 1985).
The major constraint identified was lack of adequate feed
(quantity and quality) to sustain milk production particularly
during the dry season. The research emphasis has been to
integrate fodder crops into the farming system and establish a
practical feeding programme based on planted fodder and crop
residues.
This paper focuses on the nutritional characteristics and
use of lablab (Lablab purpureus) in crop by-product-based diets
for lactating Simmental-Tswana crossbred and Tswana cows in
small-scale dairy farms in Botswana.
156
METHODOLOGY
Feed production and conservation
The project introduced lablab to 30 participating farmers. Each
farmer was provided with 20 kg of lablab seed and 100 kg of
single superphosphate fertilizer (10.5% P) to plant one hectare
of land. The fertilizer was applied to half of each hectare
allocated for planting lablab. The seed was planted either in
rows using planters or by the traditional method of
broadcasting.
Three hectares of lablab was also planted at Sebele
Agricultural Research Station. Superphosphate was applied at
the rate of 0, 100, 250 kg/ha on each of the three 1 ha plots.
Half of each plot was row planted while traditional
broadcasting was used on the other half. An additional 27 ha of
land were planted for bulk production and to examine the
optimal stage of harvest and appropriate methods for
harvesting, drying and storage.
Lablab and crop stover yields were measured using 2 metre
radius circular subplots from three random locations in each
farmer's plots and at Sebele Station. After measuring yield the
plants were harvested, sun-dried and stored for dry season
feeding. After the harvesting period the total quantities of
lablab, crop stovers and post-harvest residues stored by each
farmer were estimated. Dry-matter yields were also measured for
several sorghum varieties, millet and maize screened on-
station.
Nutritive value
Three replicate samples of fresh whole plants, leaves, stems
and roots were obtained from lablab, Tswana and ER-7 cowpea
plots to determine the dry-matter and nutrient contribution of
each plant part. Three replicate samples of sorghum stover,
millet stover, sorghum chaff, sorghum husks and sorghum bran
were also submitted for laboratory analysis.
157
The fresh whole plants and plant parts were air-dried
(60 C) prior to grinding in a Wiley Mill (1 mm screen). The
dried and ground samples were saved in airtight bottles and
analysed (in duplicate) for organic matter, crude protein,
crude fibre, ash, Ca and P according to methods approved by
AOAC (1975) and j_n vitro dry and organic matter digestibility
according to Til ley and Terry (1963) procedures.
Feeding trial
A dry season feeding trial was carried out to determine the
voluntary feed intake (VFI) and performance of Simmental-
Crossbred and Tswana lactating cows fed sorghum stover
supplemented with either 15% lablab (Diet A) 25% sorghum bran
(Moroko) (Diet B) or 100% sorghum stover (Diet C).
Treatments A, B and C contained 7.40%, 7.01% and 5.56%
crude protein; 55.56%, 63.73% and 53.90% estimated TDN,
respectively. In Treatment A lablab was mixed with the stover
by hand at the time of feeding; in Treatment B the sorghum bran
was fed separately in split used-oil drums. The animals were
also supplemented with ad libitum bonemeal-salt (1:1 w/w ratio)
and vitamins A, D, E. The Treatments A and B were randomly
allocated to six each of twelve farmers. Voluntary feed intake
(VFI) was determined in all treatment groups by measuring the
daily weight of all feed offered and weight-back over a period
of seven days and for a maximum of four 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.
Dairy cattle performance
l>aily milk yields were recorded by each farmer on record forms
provided by the project. 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. All lactating in-calf and non
pregnant cows were weighed, prior to watering in the morning,
during the first week (between days 1 to 5) of each month.
158
Calf performance
The identity of the calf and its breed, sex, dam number,
initial birth weight and birth date were recorded. Initial
birth weight were measured using a heavy-duty spring balance.
Subsequent monthly weights were measured using an electronic
mobile cattle scale with the rest of the herd.
RESULTS AND DISCUSSION
Feed production and conservation
The average dry-matter yield (ton/ha) of lablab hay by farmers
and at the Sebele Research Station is shown in Table 1. Average
dry-matter yield for 0 and 100 kg/ha single superphosphate
fertilizer application were not significantly different (P>.05)
at 1.23 (range 1.00-1.60) and 1.44 (range 1.09-1.94) ton/ha,
respectively. The dry-matter yield at Sebele Station for 0, 100
and 250 kg/ha single superphosphate application were 1.41, 1.56
and 1.70 ton/ha, respectively, but were also not significantly
different (P>.05). The results also showed no significant
differences (P>.05) in dry-matter yield between farmers' fields
and Sebele Station. Phosphorus fertilizer application resulted
in no change in plant constituents.
Random soil samples taken for soil nutrient analysis from
farmers' fields and Sebele Station were generally acidic in all
locations, with pH 4.50-4.90 at Sebele Station. There was a
wide variation in soil content for farmers' fields (3.40-13.85
ppm) and at Sebele Station (4.91-15.82 ppm). Several findings
have shown that phosphorous fertilization increases dry-matter
yield, crude protein content by stimulating nodulation, and
dry-matter digestibility of fodder legumes (Haque et al,
1986). The result from this fertilizer trial could not be
conclusive due to the low seasonal rainfall experienced in the
project area (262 to 414 mm range). The low yields and lack of
response to superphosphate application could largely be
attributed to this. Dry-matter yields of lablab did not appear
to relate closely to variations in rainfall patterns in the
159
project area. For example at Oodi (414 mm, 1.32 ton/ha DM)
yields were lower than Kopong (262 mm, 1.60 ton/ha DM). These
observations may also be attributed to planting time, rainfall
distribution and differences in soil characteristics.
Table 1. Dry matter (ton/ha) of lablab hay (Lablab purpureus)
from project farms and Sebele Research Station as
2
influenced by fertilizer application research rate .
Location and
number of Fertilizer application rate (kg/ha)
farmers 0 100 250
Oodi (4) 1.32 1.37 -
Bokaa (8) 1.00 1.0? -
Kopong (2) 1.60 1.94 -
Mmopane (4) 1.08 1.20 -
Gabane (4) 1.12 1.64 -
Kumakwane (8) 1.24 1.42 -
Mean
1.23a 1.44a
Sebele mean
1.41a 1.56a 1.70a
1. Data from three replicate yield measurements from
each of 30 project farmers' plots.
2. Single superphosphate fertilizer (10.5%P).
Means in the same row and column with same superscript
(a) are not significantly different (P>.05).
The average dry-matter yield of crop stovers on project
farms and at Sebele Station is shown in Table 2. The yields of
sorghum and millet stovers by farmers varied from 0.61 to 1.74
and 0.78 to 1.00 ton/ha of dry matter, respectively. Despite
similar rainfall patterns sorghum and millet stover yields from
the Sebele Station crop screening trial plots were higher than
those from the farmers' fields.
160
Table 2. Dry-matter yield (ton/ha) of crop stovers harvested by
1 2
project farmers and Sebele Research Station .
Location and
number of farmers
Type of feed
Sorghum Mi I let Maize Cowpea Cowpea
stover stover stover (Tswana) (FR7)
Oodi (3) 1.45 1.00
Bokaa (3) 0.61 0.82
Mmopane (2) 0.66 0.78
Gabane (1) 1.35 -
Kumakwane (2) 1.74 -
3.44(a) 2.42
Sebele 1.87(b) -
Station 3.46(c) -
3.46(d) -
1.22
(e) 3.04(f) 1.19 1.32
1. Data from three replicate yield measurements from each
farmer's plot.
2. Sorghum, millet, maize and cowpea stover yields from
Sebele agronomy and Botswana Agricultural College
screening trials.
(a) Segaolane. (d) Marupantsi.
(b) Town. (e) Serere 6A.
(c) 65 D. (f) Kalahari Early Pearl (KEP).
Maize stover yields of 3.04 ton/ha were achieved on-
station but farmers' maize generally failed. The higher on-
station yields are largely attributed to the effects of time of
planting and use of fertilizer. Farmers harvested sorghum and
mi I let stovers only.
Although farmers intercropped cowpeas with either
sorghum or millets the yields were not measured. However, the
dry-matter yields (ton/ha) for pure stands of Tswana cowpeas
and as ER.7 cowpeas at Sebele station were 1.19 and 1.32,
respectively.
161
At the end of the harvest season all farmers stored
lablab hay, crop stovers and sorghum chaff/husks for dry season
feeding. As shown in Table 3, there was a wide range in total
quantities of feed conserved. Whereas all farmers harvested
lablab from their 1-ha plots, harvesting of crop stovers
primarily depended on the family labour available and the size
of their planted field. Average quantities of lablab hay,
sorghum/millet stover and sorghum chaff or husks harvested by
farmers ranged from 1.04 to 1.65, 0.65 to 3.42 and 0.14 to 0.33
ton dry matter, respectively.
The total quantities of lablab hay, sorghum/millet
stover and sorghum chaff /husks harvested by all the thirty
participating farmers was 34.09, 56.44 and 7.17 tons dry
matter, respectively. In addition a few farmers harvested small
quantities of cowpea stover.
Table 3. Quantities of crop residue and lablab hay (ton DM)
conserved by project farmers (1985-86).
Location and Lablab Sorghum/millet Sorghum chaff/
number of farmers hay stover husks (Moko)
Oodi (4) 5.39 13.68 0.96
mean 1.35 3.42 0.24
Bokaa (8) 8.30 19.42 1.59
mean 1.04 2.43 0.20
Kopong (2) 3.29 4.23 0.29
mean 1.65 2.12 0.14
Mmopane (4) 4.55 2.60 0.99
mean 1.14 0.65 0.25
Gabane (4) 4.24 6.56 0.72
mean 1.06 1.64 0.18
Kumakwane (8) 8.32 9.92 2.62
mean 1.04 1.24 0.33
Total (30) 34.09 56.41 7.17
Overal I mean 1.14 1.88 0.24
162
The major constraint observed during harvesting and
conservation of lablab was the duration of time required to dry
the stems. Lablab leaves dry and shatter within three days
while it takes up to six weeks for the stems to dry completely.
In view of this various methods of drying and storage using
tripods, stocking on the ground and combining three rows into
one row were tried at Sebele Station. Methods of drying had no
effect on duration of drying time but the crop was baled more
efficiently from stocks and tripods with minimum dry-matter
loss due to leaf shattering, mouldiness or termite damage.
Nutritive value
Lablab and crop stover samples were submitted for laboratory
nutritive value analysis (Table 4). There was a wide variation
in dry-matter percent within the sorghum and millet stovers
harvested by different farmers. The variation in dry-matter
percent was attributed to the stage of maturity of the crops
when harvested. Conversely there was much less variation in
dry-matter percent of lablab harvested at the flowering stage.
Table 4. Percent dry matter of crop stovers and lablab
conserved by project farmers (1985-86).
Location Sorghum Millet Maize Cowpea Dolichos
stover stover stover stover lablab
Oodi 40.4 39.1
Bokaa 32.4 33.3
Kopong - -
Mmopane 35.7 30.0
Gabane 35.3 -
Kumakwane 40.5 - 53
- 21.6
- 22.3
- 24.7
- 24.9
24.8 27.5
20.4 23.9
The average nutrient compositions and in vitro dry and
organic matter digestibility of lablab, crop stovers and post-
harvest residues are shown in Table 5. The mean crude protein
and crude fibre percentage of lablab, cowpea stover, sorghum
163
stover and millet stover were: 16.44 and 27.67; 15.67 and
21.08; 6.37 and 32.52; 5.75 and 35.94; respectively. On average
the lablab and cowpea stover contained 2.5 times more crude
protein than the sorghum and millet stovers. As shown in Table
5 the dry-matter and organic matter digestibilities of lablab
and cowpea stover were higher than those of sorghum and millet
stover. The higher digestibility coefficients are attributed to
the higher crude protein and lower crude fibre content in
lablab and cowpea stover than in the sorghum and millet
stovers.
In view of these nutritional findings, diets for lactating
and in calf dairy cows in the project areas were based on
combinations of home grown lablab, cowpea, sorghum and millet
stovers and post-harvest residues such as sorghum bran (Moko)
and sorghum husks/chaff.
Table 5. Nutrient composition and j_n vitro dry-matter and
organic matter digestibility of crop stovers and
fodder legumes conserved by project farmers (1985-86)
Per cent composition of dry matter DMD DOM
Feed Organic Crude Crude Ash Ca
matter protein fibre
Lablab 90.8 16.4 27.7 9.2 0.3 0.2 59.9 57.1
Cowpea stover 89.1 15.7 21.1 10.9 0.2 0.2 74.1 70.1
Sorghum stover 91.6 6.4 32.5 8.4 0.4 0.1 54.9 49.8
Millet stover 89.5 5.8 35.9 10.5 0.4 0.1 52.2 45.1
Sorghum chaff 93.6 5.5 36.6 6.4 0.5 0.1 55.5 49.7
Sorghum husks 90.0 7.2 26.8 10.0 0.3 0.2 54.4 47.2
Sorghum bran 97.3 11.5 3.2 2.7 0.4 0.3 56.9 48.3
(1) Mean data from three replicate samples per farmer's field.
164
The fresh and dry-matter contribution of leaves, stems and
twines and roots to whole lablab, Tswana cowpea and ER-7 cowpea
plants is shown in Table 6. The percentage dry-matter
contribution to whole plants by leaves of Tswana cowpeas
(57.8%) were higher than lablab (47.0%) and ER-7 cowpeas
(48.5%). Stems and twines for lablab (46.6%) and ER. 7 cowpeas
(40.5%) were higher than Tswana cowpeas (31.1%). Overall, on
both fresh and dry-matter basis the contribution of leaves to
whole plant was higher than stems and twines in all three
crops. Roots constituted a very small proportion of the total
dry-matter in the plants studied.
Table 6. Fresh and dry-matter percent contribution by plant
parts to whole lablab and cowpea residue .
Dolichos Lablab Cowpea (Tswana) Cowpea (ER-7)
Plant parts Fresh Dry Fresh Dry Fresh Dry
Leaves 53.3 47.0 62.9 57.8 57.4 48.0
Stems and twines 42.8 46.6 30.0 31.1 35.0 40.5
Roots 3.9 6.4 7.1 11.1 7.6 11.5
Whole plant 100.0 100.0 100.0 100.0 100.0 100.0
1. Mean data from three replicate samples of whole plants
divided into plant parts.
The nutrient composition of fresh lablab, Tswana cowpeas
and ER-7 cowpeas is shown in Table 7. There was a marked
difference in crude protein and crude fibre percentages between
leaves, stems and twines and roots in all plants. The crude
protein and crude fibre percentage of fresh leaves of lablab,
Tswana cowpeas and ER-7 cowpea were: 19.37 and 19.32; 21.24 and
13; 22.86 and 11.52, respectively. The average crude protein
content of leaves was not greatly different. Stems and twines
were generally lower in crude protein and higher in crude fibre
than the leaves. However, as shown in Table 7, there was less
difference in the crude protein content of leaves and
stems/twines in the cowpea plants than in the lablab plants.
165
Table 7. Nutritient composition of lablab and cowpea residue
whole plant and parts
Dry Composition of dry matter (%)
matter
(%) Organic Crude Crude
Lablab
matter protein Fibre Ash Ca P
Leaves 21.6 87.8 19.4 19.3 12.2 0.7 0.1
Stems and twines 26.7 92.7 11.5 37.1 7.3 1.1 0.1
Roots 41.1 93.9 6.0 45.4 6.1 1.0 0.1
Whole 25.3 91.5 16.6 30.3 8.5 0.6 0.2
Cowpea (Tswana)
Leaves 16.9 84.9 21.2 13.1 15.1 0.5 0.3
Stems and twines 19.1 90.3 21.0 18.5 9.7 0.3 0.3
Roots 28.8 93.0 12.7 18.5 7.0 0.2 0.2
Whole 21.2 85.4 21.3 16.8 14.6 0.3 0.2
Cowpea (ER7)
Leaves 19.1
Stems and twines 26.5
Roots 34.7
Whole 25.4
85.0 22.9 11.5 15.0 0.5 0.3
92.5 19.4 21.3 7.5 0.2 0.3
94.7 11.1 23.5 5.3 0.3 0.2
88.5 19.2 18.3 11.5 0.4 0.3
1. Data from three replicate samples of whole plants from
Sebele Research Station.
Summaries of the mean dry organic matter j_n vitro
digestibility coefficients of fresh lablab, Tswana cowpea, ER-7
cowpea whole plant and plant parts are given in Table 8.
Digestibilities of the dry matter and organic matter in lablab
leaves were higher (67.85, 62.22) than in stems and twines
(56.97, 50.78), but in the cowpeas the digestibilities of the
stems and twines were higher than in the leaves. Between the
plants the digestibilities of dry matter and organic matter
166
were higher in Tswana and ER-7 cowpeas (73.57% and 73.85%) than
in lablab (67.85%).
Table 8. J_n vitro dry-matter and organic matter digestibility
(DMD and DOM) of lablab and cowpea residue whole plant
and parts
Lablab DMD(%) DOM(%)
Leaves 67.8 62.2
Stems and twines 57.0 50.8
Roots 46.9 43.8
Whole 60.8 55.1
Cowpea (Tswana)
Leaves 73.6 71.5
Stems and twines 84.2 82.7
Roots 74.3 73.3
Whole 72.3 71.7
Cowpea (ER7)
Leaves 73.8 73.1
Stems and twines 77.5 77.0
Roots 76.7 76.2
Whole 71.4 69.8
1. Means represent data from three replicate samples.
Feeding trial (dry season)
The average chemical composition and voluntary feed intake by
farmers' lactating cows fed diets of 85% sorghum stover + 15%
lablab (Treatment A), 75% sorghum stover + 25% sorghum bran
(Treatment B) and 100% sorghum stover (Treatment C) were
presented previously (Mosimanyana and Kiflewahid, 1987).
167
Chemical analysis of the lablab and sorghum bran-
supplemented diets indicated that the crude protein percentages
were 7.40 and 7.01, respectively and higher than the sorghum
stover only diet which contained 5.56% crude protein. The crude
protein content of sorghum stover was lower than the minimum
7. 0% required for maintenance. In Treatments A and B the crude
protein contribution to the diet by lablab and sorghum bran was
37. 7% and 39. 4%, respectively. In terms of the crude protein
contribution to the sorghum stover-based diet 15% lablab was
equivalent to 25% sorghum bran.
Mean daily dry-matter intake (DMI) during the trial period
for the three treatments was lower for the lablab diet (8.27 kg
DM/day) than for the Sorghum bran (10.21 kg DM/day ) and the
sorghum stover only (8.96 kg DM/day) diets.
Dairy cattle performance
The lactation data of the Simmental-Tswana crossbred and Tswana
cows fed diets of sorghum stover supplemented with 15% lablab
or 25% sorghum bran, are summarised in Table 9. Complete
lactation data of the cows fed the sorghum stover only diet
could not be obtained since farmers started to supplement their
cows with either lablab or sorghum bran prior to the end of the
lactation period.
The average lactation length of Simmental-Tswana crossbred
and Tswana cows fed the 15% lablab and 25% sorghum bran diets
were 270 and 240, 276 and 206 days, respectively. Lactations
for Simmental-Tswana cows were longer (P<0.5) than for Tswana
cows. There were no significant differences (P>.05) in
lactation length within breeds fed different diets.
Average daily milk yield/cow for Simmental-Tswana
crossbred and Tswana cows fed the 15% lablab and 25% sorghum
bran diets were 2.2 and 3.4, 1.4 and 1.6 kg/day, respectively.
Within breeds the milk yields were higher for cows fed the
sorghum bran but not significantly (P<0.05). There were wide
variations in daily milk yield within breeds and between
treatments. These observations could be attributed to the
168
variation in genetic potential of the individual Simmental-
Tswana crossbreeds and Tswana cows owned by the different
farmers (APRU, 1986; DPR, 1987).
1 2
Table 9. Milk yield of Simmenta I -Tswana (SX) and Tswana (TS)
cows fed sorghum stover supplemented with lablab or
sorghum bran (1985-86).
15% Dolichos Lablab + 25% sorghum bran
85% sorghum stover 75% sorghum stover
SX TS SX TS
Number of lactating cows 5
Average lactation length (days) 270a
Total milk yield/herd (kg) 2941.3
Average lactation yield/cow (kg) 588. 3a 340
Average milk yield/cow/day (kg) 2.2a
12 5 12
240b 270a 206b
080.6 4655 4040.1
b
931*
336. 6b
1.4b 3.4a 1.6b
1. Excluding milk left over for calf.
2. Milk recording period 1st lactation (Nov. '85-Sept. '86).
3. Plus ad lib bonemeal -salt (1:1 W/W ratio) and vitamin A,D,E.
Means in the same row with different superscripts (a,b) were
significantly different (P<0.05).
The average milk yield/cow/lactation for Simmenta I -Tswana
cows fed the 15% lablab and 25% sorghum bran diets were 583.3
kg and 931.0 kg, respectively. These values were not
significantly different (P>.05) due to the large variation in
milk yield within the Simmental crossbreeds. The milk yields of
the Tswana cows for the two treatments (340 kg, 15% lablab diet
and 336.7 kg for 25% sorghum diet) were also not significantly
different (P>0.05).
At the end of the lactation period total milk produced by
ten Simmental -Tswana and twenty four Tswana cows was 15,717.4
kg of which 7596.7 kg was from the ten crossbred cows and
8,120.7 kg from the 24 Tswana cows. On average under similar
169
feeding and management systems each Simmental-Tswana crossbred
cow produced 2.25 times more milk than Tswana cows. These
observations are comparable to data obtained from similar
trials on-station (APRU, 1986, DPR '86-87).
Average seasonal liveweight change patterns for both
Simmental-Tswana crossbred and Tswana cows were similar.
Despite dry season weight loss average initial liveweight for
Simmental-Tswana (422 kg) and Tswana cows (379 kg) were not
greatly different than weights for the same Simmental-Tswana
(417 kg) and Tswana cows (365 kg) recorded after twelve months.
Calf performance
The average liveweight changes of all calves are summarised in
Table 10. Birth weights of Simmental-Tswana calves (34 kg) were
higher than Tswana calves (28 kg). Growth patterns of both
breeds were similar. In terms of management all calves had
access to their dams until the end of the lactation period and
weaning coincided with the end of the lactation. On-station
trial results have indicated that suckling prior to milking not
only stimulates milk let-down but also prevents premature
drying-off. Average liveweight at 12 months of age for
Simmental-Tswana and Tswana calves were 147 kg and 124 kg,
respectively. Unlike dry season weight losses experienced by
adult cows the calves gained weight throughout the year.
Table 10. Monthly liveweight of Simmental-Tswana (SX) and
Tswana (TS) calves (1985-86).
Breed No. Birth Liveweight for age in months
weight
1 2 3 4 5 6 7 8 9 10 11 12
SX 7 34 43 55 75 86 97 105 111 119 129 133 141 147
TS 25 28 35 43 49 60 72 82 92 102 110 115 119 124
170
CONCLUSION
The feeding system for in-calf and lactating Simmental -Tswana
crossbred and Tswana cows is based on local feed resources. The
dry season feeding strategy using high protein farmer-grown
lablab hay (Lablab purpureus) in association with crop by
products and residues has been a significant intervention in
small-scale dairy farms in Botswana. Despite low seasonal
rainfall 30 dairy farmers participating in the project
harvested and stored 34.1, 56.4 and 7.2 tons dry matter of
lablab hay, sorghum/millet stover and sorghum chaff/husks,
respectively.
The study demonstrated that there was no significant
effect (P>.05) of single superphosphate (10. 5%) application on
dry-matter yield of lablab in both farmers' and on-station
trials. However, wide variations in lablab and crop stover
yields were observed within and between farms and project
localities.
Chemical analysis results showed that on average lablab
hay and cowpea stover contained 2.5 times more crude protein
than sorghum and millet stovers. When lablab and cowpea whole
plants were partitioned into leaves, stems and twines and
roots; the dry-matter and nutrient contribution of leaves was
higher than stems and twines.
A comparative (on- farm) feeding trial based on sorghum
stover supplemented with either lablab or sorghum bran showed
that under farmers' management conditions Simmental -Tswana
crossbred cows produced 2.25 more milk per lactation than
Tswana cows.
REFERENCES
AOAC (Association of Analytical Chemists). 1975. Official
methods of analysis. 12th Ed. AOAC, Washington, D.C.
APRU (Animal Production Research Unit). 1985. Livestock and
range research in Botswana, Annual Report 1984-85.
Government Printer, Gaborone, Botswana.
171
APRU (Animal Production Research Unit). 1986. Livestock and
range research in Botswana, Annual Report 1985-86.
Government Printer, Gaborone, Botswana.
DPR. 1987. Dairy Project Annual Report, 1986-87. Animal
Production Research Unit, Gaborone, Botswana.
Haque, I.; Nnadi, L.A. and Mohamed-Saleem, M.A. 1986.
Phosphorous management with special reference to
forage legumes in sub- Saharan Africa. In: I Haque, S.
Jutzi and P.J.H. Neate (eds), Potentials of forage
legumes in farming systems of sub-Saharan Africa.
Proceedings of a workshop held at ILCA, Addis Ababa,
Ethiopia, 16-19 September 1985. ILCA, Addis Ababa,
Ethiopia. pp. 100-119.
Mosimanyana, B. and Kiflewahid, B. 1987. Feeding of crop
residues to milking cows in small-scale farms in
Botswana. In: D.A. Little and A.N. Said (eds),
Utilization of agricultural by- products as livestock
feeds in Africa. Proceedings of ARNAB workshop held at
Blantyre, Malawi, September 1986. ILCA, Addis Ababa,
Ethiopia. pp. 127-135.
Snedecor, G.W. and Cochran, W.G. 1967. Statistical methods.
6th ed. Iowa State University Press, Ames, Iowa.
Til ley, S.M.A. and Terry, R.A. 1963. A two stage technique for
the j_n vitro digestion of forage crops. I. Brit. Grassl.
Soc. 18:104.
172
CEREAL STRAWS IN THE FEEDING SYSTEM OF RUMINANTS IN SENEGAL
S. Fall, H. Guerin, C. SaIl and ND. Mbaye
Departement de recherches sur les productions et la sante animaIes
Institut senegalais de recherches agricole (ISRA)
Laboratoire national de I'elevage et de recherches veterinaires
(LNERV), BP 205, Dakar-Hann, Senegal
ABSTRACT
Cereal straws represent an important source of energy. However
they contain low concentrations of nitrogen, minerals &
digestible energy which requires a good supplementation.
Preference should be given to agro- industrial by-products
available in the areas of cereal production. In the peanut
basin and in the South, cereal straw can be supplemented by
peanut cake, cottonseed, sorghum, millet & rice brans.
The rice agro- industrial by-products (rice polishing,
rice bran) can be fed together to support high levels of
production. This feeding package is suited to the northern and
southern part of Senegal.
Treatment of straws with urea is the most promising
alternative solution in order to enhance straw utilisation by
ruminants. Urea which is an important source of non-protein
nitrogen is available to farmers at low cost.
On-farm research should be geared towards comparing the
economic feasibility of two alternative solutions: treatment
and supplementation of cereal straw with urea.
INTRODUCTION
The drought which adversely affected the Sahelian countries of
Africa during the past two years has now receded. However, the
173
available biomass remains insufficient. Nutrition is still the
major constraint to the improvement of livestock productivity
in Senegal. The challenge for research workers, livestock
technicians and farmers is to develop efficient feeding systems
using the available feed resources in Senegal. Within the
framework of crop- I i vestock interactions, low quality crop
residues such as feed resources can play an important role in
meeting the dry-matter and energy requirements of ruminants.
In 1986, 887,820 tons of maize, millet, sorghum and rice
grain were harvested. The estimated straw output is 4,800,000
tons. This available quantity is expected to increase soon
with the development of irrigation in Senegal river basin. The
main areas of production are the groundnut basin, Senegal river
basin, Tambacounda and Casamance.
Previous studies carried out in the Laboratoire national
de I'elevage et de recherches veterinaires (LNERV) have
investigated the problems of low concentration in digestible
nutrients, bulkiness and low digestibility of cereal straws
(Calvet et al, 1974).
Offered alone, cereal straws cannot meet the
maintenance requirement of cattle, sheep or goat. They need to
be supplemented with concentrates in order to support
reasonable milk or meat production. Chemical treatment can
also improve digestibility of low quality roughages.
Supplementation and alkali treatment of cereal straw
have been carried out in LNERV and IEMVT. The objectives of
this paper are to describe experimental procedures, discuss
available results in order to set up the best way of
integrating cereal straws in Senegal's ruminant feeding system.
EXPERIMENTAL PROCEDURES
Supplementation of rice straw
The main objectives of rice straw supplementation was to
improve rumen environment and increase straw digestibility.
174
Rations were intended to allow either maintenance or low to
medium levels of meat/milk production. Thus rice straw used
was analysed and the chemical composition is given in Table 2.
Composition of the complete qations and number of trials are
specified in Table 1.
Table 1. Cereal straw supplementation.
I Rations Species Number Level of *
of trials concentrate (%)
|Rice straw + cottonseed Sheep 7 26
|Rice straw + peanut cake ii 7 10
I " ii Cattle 2 6.5
I " H ii 8 10
I " ii ii 3 15
|Rice straw + rice polishi ng ii 12 22
i ii ii Sheep 2 45
|Rice straw + rice broken
| grain ii 6 28.5
|Rice straw + molasses+urea ii 2 21.5
|Rice straw + P Cattle 6 20
P = mixture w/w of rice polishing and maize bran.
Alkali treatment of cereal straws
NaOH and urea treatments of cereal straw have been
comparatively carried out. To avoid unjustifiable excessive
loss of water and nutrients a semi -dry method (Jackson, 1979)
was applied.
Different levels of urea (3.5 and 6 g/100 g of straw) and
sodium hydroxide (3,4,5 and 6 g/100 g of straw) were tested.
The effects of urea treatment in different species of cereal
straw, millet, sorghum, maize and rice has been summarised in
Table 3 and 6.
175
Table2.Ehemicalv luofagro-industriaby-productsuses
supplement.
Eotton (g/kgEM) 1.5 5.1
seed 00 100 S0
554
S6
industrial
extract
by-product
Agro-
ber
Etherextract -free
Phosphorus
Fractions
Protein
Erudefi Nitrogen Ealcium
Ash
Rice
brokeng ain
N=6
(g/kgEM) 153+7 81+0 70+1 16+0 683+10
1.2 -
Rice
polishing
N=11
(g/kgEM) 63+3 119+53 65+30 44+32 508+242 0.8+1 2 10.7+0,0
Mixturew/w
ricepolishing
+maizebran
No=1
(g/kgEM)
100 100 55 76 608
1.1 9.5
|Peanut |cake
|N=13
|(g/kgEM) |52+ |504+ |28+9
I7+0
|488+24
I1-2
|6.2
^i
&
Evaluation of the nutritive value of rations
The nutritive value of supplemented rice straw, and alkali -
treated cereal straws were evaluated by chemical analysis and
in vivo digestibility trials. Chemical analysis involved
organic matter, crude fiber, crude protein, NDF, ADF, lignin,
silica and minerals. J_n vivo digestibilities were carried out
with six cattle or sheep. This protocol was broken down into
phases: 15 days of adjustment and 6 of measurement.
RESULTS AND DISCUSSIONS
1. Rice straw supplementation
1.1 Peanut cake
Peanut cake is available in the whole groundnut basin and in
the south of Senegal. Rations based on rice straw supplemented
with cake were well accepted by cattle and sheep (Table 3).
However, high levels of peanut cake depressed digestibility of
straw, and therefore the level of peanut cake should be
restricted. Previous studies have also shown the depressive
effect of peanut cake on organic-matter digestibility (OMD) of
straw when fed at high levels. Data in Table 4 show a
significant (P<0.05) depression of rice straw OMD at the level
of 500 g peanut cake per day (10 per cent). It is also evident
that rice straw OMD was not significantly improved by feeding
at the rate of 250 g of peanut cake per day.
177
oI
Im
a
-3>
-8
01
3
Urea1treated|
ricestraw ♦molasses
+urea
a.i
cm
co II (2 ■
IM
O II
CM
CM
O II
Urea1treated
ricestraw
+urea
5
CO z ■
z
z
z
| s: 5 N S " r^ II in iiro01 ■ z z z
c/i
Ricestraw
+rice
break f
in <o
+ 1 II
cm <o
+ 1 II
CO 1o
+ 1 II
CM z
CM
o <o
+ 1 II + 1 ii
x: s ■ N. Z CM z s *
Ricestraw
+rice
polishing
+maize
CO m
c
C
CM O 1o <o
+ 1 II
in z
K)
cm 1o
+ 1 ii
~* <o
+ i ii+ 1 II + 1 II
CM z«- z ft ■ m z
Ricestraw
+peanut
cake
2 m om
a
I rO -» ii
CM
CO II
cm
f- II
CM
rC ii
CM
C> II
(M
.c R " z « z z ro z z
a
Ricestraw
+ricepol shing Si 1 ■ 1
O st in >* CM -^ •O •*
01
ro •- CM «- CM
M
+ 1 II + 1 II + 1 H + 1 II + 1 II •- II
*-* 0> z 3 * s * «- z O Zm Za
u a
*
u
Rations
|Analysis
« *
CD
c
M
X
01
c
•
*
y 1
1 L. tDl_
+*
K
01
ft-
p 1
|
iu l.a « Ii.i | 1.L.
O
L.
CJ U
01
.C*-'
U1
Q
z z
178
oi
ID
s
(D>
o
1
18
I
§
u
Urea1treated
ricestraw +molasses
+urea
CM CM
M
a
%
SI
• II • II
IM
Urea1treated
ricestraw
+urea
O1
z z
8- IO in
01 • II
ro
• ii
Ricestraw
+rice
break a o <o
z
o
z
i + 1 II
Ricestraw
+rice
polishing
+maize
.c
to -0 z
c
eg
o <o
+ 1 II
o <o
+ 1 ii
1* z
N
Ricestraw
+peanut
cake
I-- z
a
rM
a
^t II
in
CM
II
CM
in
Si CM II «- ii CM II
-C 2 z z z z
Ricestraw
♦ricepolishing
a
CO
• -J. ■- >o
+ 1 ii
o z
01
iM
O
iM
•O + 1 II
o «-
*-* CM II
z
** II
Z
o z
o
+ 1 II
o z
ID
1Rations
|Analysis
o rvl
*
* ft * 3
1
u.
c IO s L.
E u
to
■s.
U in
o
<
a
to
o
a.CJ
179
oi
■5
g
u
p
s
Urea1treated
ricestraw +molasses
+urea aSi
Vi
Urea1treated
ricestraw
+urea 1JZ
Ricestraw
+rice
break I
VI
Ricestraw
+rice
polishing
+maize c
ca
C_
25
Ricestraw
+peanut
cake
O
• CM
m in 10 cm
CM CM
CM II
* CM . CM 0
i •- II 0 II
r~- N- II
II ~*
0 II
55
t
Z z
z In Z
Ricestraw
♦ricepol shing
el
•o
«- >o CM CM
ai
0 >o
£1 " II II CM
»- z CO II
O M z
CM
+ 1 II
r^ z 0 z 0 1l
a
u
CM Z
a >* § Zin
8
*-> 1 H.
a > K
S
(A § s 18 . i
1
(A
si (A 3 *J 2
£ 0)
J 1 .£
a
1
a
0
en
CD
CO BX a. (_) CI rsi X
180
oI■5
s
1
1ffl
u
1
-8
4-*
c
8
I
01
Urea1treated
ricestraw +molasses
+urea
|
iM
O II O1 II
in
Urea1treated
ricestraw
+urea
in
z
|
•o "~■* ii <o "~
Ricestraw
+rice
break
M
m ii
z
I + 1 M
ro >0
+ 1 ii
o z
in
CO z
Ricestraw
+rice
polishing
+maize
m
c
+ 1 H + 1 N
Ricestraw
+peanut
cake
CO
1
K)
O II
«- z
>* ii
■
in I)
z
1
Ricestraw
+ricepolishing * S- II
CM
m ii
m
z
K) K)
z
II I\i + 1
+ 1 "12
II*-* S. II iio> fJ Z
a
o
c> z
in z
V)
<
18
I
L.
01
+> *-*
+> X
9 ^^
O —'
I
l_
0)
4->
i s
IO >■
i 1z
o —
181
o■g
IS
6
6
Urea-treated
ricestraw +molasses
+urea
|
cM ii «- ii
(A
K)
z
>*
z
Urea1treated
ricestraw
+urea | •o "~ oV O II •* II
JtI/> z
Ricestraw
+rice
break 1 IO >0 ir> o+ 1 ii
o> z
+ 1 II
Ricestraw
+rice
polishing
+maize
O Z
c
■- <o
to + 1 II
C
M z
+ 1 II
Ricestraw
+peanut
cake
Kf r- z
|
Kl
rvi
1
O II
z
m II
z
Ricestraw
+ricepol shing M II
z
m ii
z
is. 2
+ 1 N
CM Z
(\l «-
+ 1 II
■ r\I zo
Rations
Analysis
Digestiblecrude Voluntaryintake
g/kg0.112
•
protein
I 182
Table 4. Digestibility of rice straw in complete diets compared
to rice straw offered alone.
Rations Species Organic-matter
d gestibi lity (%)
| Rice straw N _ 15 Cattle 64+ 4
| Rice straw N = 15 Sheep 58+ 4
1 " + peanut cake 500 g/day N = 8 Cattle 59.6+ 2.7
1 " ■ 1 kg/day N = 3 ii 59.3+ 2.0
i ii " 250 g/day N = 2 ii 68.4+ 0.6
1 " + rice polishing
+ maize bran N = 6 ii 80.9+ 1.5
1 " + rice polishing N = 12 ii 73.8+ 4.4
i ii + rice broken grain N = 6 Sheep 37.1+ 5.7
In conclusion, peanut cake raises the nitrogen, energy
and phosphorus levels of rations based on rice straw, but
should be limited to a maximum of 10 per cent of the diet. The
alternative use of urea to correct nitrogen deficiency is a
possibility (Table 5).
1 .2 Cottonseed
Cottonseed cake and rice straw are both produced in Casamance
and Tambacounda. Experiments have shown that these can be fed
together to support reasonable levels of production (Table 6).
183
However, the data are very limited. Table 6 suggests an
addition of urea to reach the semi - intensive beef production
allowed by the energy level of the ration.
1.3 Agro- industrial by-products of rice
Broken rice, rice polishings and bran total to substantial
quantities. When fed alone or in association (w/w) with maize
bran, rice polishings give an adequate supplementation to rice
straw. Significant (P<0.05) improvements in OMD (Table 4) were
obtained in a number of experiments. The rations with high
levels of energy could support fattening of cattle. Further,
the possibility of incorporating urea as a source of nitrogen
is an added advantage. Broken rice grain is rich in starch,
and can be fed up to 10% in ruminant diets but too high levels
have a depressing effect on straw digestibility. This by
product should be reserved for poultry.
1.4 Urea and molasses
It is well documented that urea is a cheap nitrogen source able
to improve intake and OMD of low quality roughage. In Senegal,
molasses and rice straw are available in the same area (Senegal
rice basin). The combination of rice straw, molasses and urea
gives a mixture which is well consumed by ruminants. The
addition of peanut cake and minerals could allow intensive or
semi -intensive beef fattening.
184
o■s.
8
§ £
o «- «-
«- »*
fM «- «- o f\J
Vl Tl *|
*
+ 1
CM Kl
*-. Ml
2 S
o o o
m >». in
o o o
o
+ 1
o o «- «-
o o o o.
+ 1 +1 +1 +1•O N- m ro
o o
±' +1CO «•
•*. ""*. "•*.
V £' rt'
<6 in in
«*'
IC
«>. N-. •>*■. «-.
3 8 8
+i
«- cm m
o o >0
•• in
+ 1 +1
ro >b
Y
on » m n
o in v<3
in
in in
>o fM in
fM t>
ro R in oin
3 (\i cm «- ro fO in
O CD +i +i +i + 1 + 1 + 1 + 1 +1 + i + 1 + 1 + 1
o r\j ro mK m >*• in 8 in 8 «
•O
cm>0 CO o c> in o*•» co o in 90 in >l- «- CO cm rO o >o vOCO «- (\J (M cm (M CM cm ro ro «~ cm
cm ro cm
(A
0) 4> 0) V
a
|
— a
■ « 2!
a *-> 8 :- - -
<D -C CO JE CO f
CO U (/) u (A u CO
s s
(A (A
oo c» M•- — •
8.
Sft o 00 iB ft « •- •- ft o — ■- fc •-
Q.'v.Q.iJ Q. *v c- (- Q. «- c ca jQ l.
(/) CO (/) (/) 8
+
c L. in L-
9 T3
o E "~ Si_ (O co
-Q 8 co(A
II 8 3 (0u
7 + g_
C i 3
tt in oc i-
185
2 Alkali treatment of cereal straw
2.1 Urea treatment of cereal straw
The treatment of straws with urea improved intake,
digestibility and nitrogen concentration in rice, millet,
sorghum and maize crop residues (Table 6).
Table 6. Urea treatment of cereal straw comparision of rice,
millet, maize, and sorghum straws.
| Cereal straws CP (%) DM0 (p. 100) Intake g/kg (p 0.75) |
Processed 7.9 n=1 54.48+3.76 61.0+9.5 n = 6 |
| Rice straw
Control 4.5 n=1 42. 8+3.6 47.7+2.8 n = 5 |
Processed 14.9 n=1 57.2+4.8 n=6 52.6+10.3 n = 6 |
| Maize straw
Control 3.9 n=1 49.3+2.4 n=6 39.5+4.6 n = 6 |
Processed 14.10 n=1 58.8+5.5 n=4 56.1+3.4 n = 4 |
! Millet straw
Control 8.4 n=1 39.2+6.4 n=5 31.5+6.8 n = 4 |
Processed 14.60 n=1 65.1+2.7 n=6 68.4+ 3.4 n = 6 |
Sorghum straw
Control 4.2 n=1 47.2+4.7 n=2 49.8+ 6.2 n = 5 |
186
Compared to maize and sorghum, millet residues gave a
superior improvement of intake and digestibility while the
first had a higher capacity of nitrogen fixation. The results
in Table 8 describe the effect of urea concentration on cereal
straw improvement. The optimal level of application was found
to be 5 g of urea per 100 g DM of straw.
2.2 NaOH treatment of millet straw
Available results show a positive influence of NaOH treatment
levels on millet straw digestibility (Table 7) but chemical
composition of the straw did not undergo any changes (Table 8).
The incubation time had no major influence on the improvement
of the nutritive value of straw. The minimal incubation time
was found to be 24 hours.
Table 7. Dry-matter digestibility of millet straw treated with
NaOH.
Incubation time
24 hours
48 hours
96 hours
NaOH concentration (g/kg)
30
52.6
52.4
52.2
40
56.1
57.6
56.4
50
58.6
57.2
57.9
60
62.5
62.6
62.8
Control = 36 p 100.
Source: ISRA-LNERV (1977).
187
!
M
%
1
"8
U-
89 KSR>»Ki?sR3jR™S*o
—j
s ^OwSiriiiSiriNjWin^R
c
I « S8&!8F2«&!e$&l£$
_l
u.
39
Nitrogen extract
3 S§!S§3§5§§§33free
8
Ri 5RjSK)Kl?5?32cQRfeR3
a
m 5«^«3K5f«SRSU
a.
Erude protein
s SSS&SS&SSSSS
3 Nx^fOFnroKimFOsT>Tf'i
II fM ^tt)^SO^OOCO^^OOK
1 s wfcfcfcaasKtfssfc
Analysis g/kgEM
§ 0s Q< (^ o^ Qk o^ o1* c^ ^ (^ <^> (^
Millet straw 8
1 1 1 1 1 1 1 1 1 1 1 1
X X X X X X X X X X X X1
O) t_
c o ^
O JC N-
— r>>-
*-> <u o
<0 E «-
c >
0» C CK
o o ujc ■- z
O *-> _l
u <o 1
-Q <
x 3 ec
O O </)
(0 c —
«- oj o
v w to
188
ACKNOWLEDGEMENTS
The authors are grateful to Mahawa Mbodj, Adama Faye and Didier
Richard for making a critical review of this paper. They are
also indebted to Abdou Fall for his help in translating the
text.
REFERENCES
Calvet, H.; Valenza, J.; Boudergues, R.; Diallo, S.; Friot, D.
and Chambron, J. 1974. La pa i lie de riz dans
I' alimentation animaIe au Senegal. I. Analyses
bromatologiques. Digest ibi I i te in vivo et in vitro.
Bilans azotes et mineraux. Rev. Elev. Med. Vet. Pays
Trop. 27(2): 207-220.
ISRA - LNERV. 1977 - Rapport sur le f onctionnement de I'annee
1977. ISRA-LNERV, Dakar, Senegal.
Jackson, M.G. 1979. Le traitement des pailles pour
I 'al imentat ion des animaux. Evaluation de la
rentabilite technique et economique. FAO, Rome. 68 pp.
189
OVERCOMING SOME CONSTRAINTS IN FEEDING CROP BY-PRODUCTS
FOR MILK PRODUCTION
K. M. Biwi
Ministry of Agriculture
Department of Livestock Development
P.O.Box 159, Zanzibar, Tanzania
ABSTRACT
Supplementation of concentrate and leucaena to dairy cattle fed
on sodium hydroxide "dip"-treated and untreated maize stover
was compared with an elephant grass-based diet in a latin
square 3x3 change over design using 18 lactating dairy cows.
Dry-matter intake, energy intake and milk production were
studied.
The dry-matter intake of the test roughages and the ME
intake from the total dry-matter intake of treated maize
stover-based diet, untreated maize stover-based diet and
elephant grass-based diet were 3.37, 3.11 and 4.92 kg
DM/cow/day respectively, and 86.50, 75.40 and 81.34 kg
MJME/cow/day, respectively. The dry-matter intake of the test
roughages and ME intake were significantly different (P<0.01)
between the treatments.
Actual milk yield and 4 percent FCM for TMS-based diet,
MS-based diet and EG-based diet were 7.7, 7.6 and 7.7
kg/cow/day, respectively and 9.5, 8.8 and 9.3 kg/cow/day,
respectively. The MS-based diet produced significantly low FCM
yield (P<0.01); but yield of actual milk was not significantly
different (P<0.05) between the treatments. Higher concentrate
allowance in MS-based diet improved actual milk yield but not
FCM.
190
INTRODUCTION
Inadequate feeding during the dry season is a serious problem
in Tanzania because in many areas grazing is the main form of
cattle feeding. Judicious use of alternative feeds from crop
residues can alleviate the problem of feed availability since
straws and stovers are abundantly produced in the country
(Kategile, 1982). However, the utilization of these crop
residues is beset with inherent constraints of low protein,
energy and mineral content which often cause inefficient use of
the materials due to unacceptabi lity by animals. Manipulation
of feeding practices of these crop residues by moderate
supplementation of protein, energy and minerals as well as
chemical treatment can overcome these constraints and thus
improve intake when fed to ruminants.
In this experiment, home-made concentrate and dried
leucaena leaves were used to supplement treated and untreated
maize stover fed to lactating dairy cattle for milk production,
with elephant grass as a control roughage. Dry-matter intake,
ME intake and milk production were measured.
MATERIALS AND METHODS
Study area
This work was carried out at Sokoine University of Agriculture.
Roughages used
The roughages used were maize stover, elephant grass
(Pennisetum purpureum) and leucaena (Leucaena leucocephala) .
The choice of maize stover was influenced by its abundance
after the grain harvest and its potential as a dry season feed.
The elephant grass was chosen because it is drought-resistant
and grows naturally throughout the year in many areas along
water courses. It is also a potential green forage for stall-
feeding during the dry period. Leucaena flourishes well in
coastal areas and grows naturally in many areas.
191
Procurement and preparation of the feeding materials
Maize stover was collected from the University Farm after the
grain harvest and stored undershed before chopping in small
pieces using a large hand knife. The sizes were in the range
of 4-6 cm to facilitate easy mixing of leaves and stems. The
chopped stover was divided into two portions, one for alkali
treatment and other portion to be used untreated.
The alkali treatment method employed was the "dip"
method developed and described by Sundstol (1981). The chopped
maize stover was dipped in 1 per cent sodium hydroxide (NaOH)
solution. The ratio of maize stover to solution was 1.15
(W/V). The untreated maize stover was soaked in plain water
using the same ratio.
Elephant grass was collected from natural stands mostly
along the river courses at the university premises. Vegetative
parts were cut everyday and chopped into 4-8 cm to facilitate
easy feeding.
Leucaena forage was collected and dried on concrete
floor, and packed in bags.
The concentrate was made up of cassava flour, maize bran,
cottonseed cake, urea, salt, Macklik supper and Vitamins A and
D. The mixture was formulated to have approximately 17 percent
crude protein.
Experimental design
The experiment was carried out in a 3x3 latin square change
over design, with a set of six (3x3) latin squares (multiple
classification including partition into within and between
square variances). Eighteen mature cows of medium milk
production were selected from the University farm. Three
breeds Jersey, Ayrshire and Friesian were used.
There were three experimental periods denoted as P1, P2
and P3. Each period lasted for three weeks and was proceeded
192
by a transitional period of two weeks. At the beginning of the
experiment a longer period was required to adjust the animals
to reasonable intake of the test roughages, particularly the
untreated maize stover.
Feeding of the cows
The basal roughages of supplementary leucaena dried leaves was
fed with concentrate at the stalls. Cows on sodium hydroxide-
treated maize stover (TMS) and elephant grass (EG) received 0.6
kg concentrate for every 1 kg FCM after the first 4 kg of FCM,
while those on untreated maize stover (MS) received 0.75 kg
concentrate for each 1 kg FCM after the first 4 kg FCM.
The first feeding for the test roughages TMS, MS and EG
commenced immediately after the feeding of concentrate and
basal roughages in the morning, and the second feeding was
after the evening milking. All the feeds were offered
individually to each cow and the weights offered recorded.
Refusal of test roughages were weighed the next morning for
each individual cow, and daily intake was also recorded.
Measurements
The effects of the diets fed to the cows were measured in the
following variables:-
1. Dry-matter and energy intake
2. Milk yield and composition
3. 4% fat corrected milk
Data collection
The dry-matter intake of the test roughages were obtained by
the difference between the dry-matter offered and that refused.
Total dry-matter intake of the whole diet was recorded.
Morning and evening milk were recorded in kilogrammes
and summed to make a total for a day's milk yield for each cow.
A sample of milk in the morning and evening for two consecutive
193
days per week was taken and a subsample taken for chemical
test. Milk fat content was analysed by the Gerber method
(British Standard Institution B.S., 696, 1955). The 4 percent
fat-corrected milk was calculated according to Gaines formula
as described by Maynard et al (1979). Crude protein content
was analysed by Kjeldahl method as outlined by A.O.A.C. (1965)
(CP = %N x 6.38).
Statistical analysis
The analysis of variance for latin square design was carried
out as described by Snedecor and Cochran 1967; with multiple
classification including partition into within (w'n) and
between (b'n) squares variance i.e. treatments b'n squares,
columns w'n squares and rows w'n squares.
The new Duncan Multiple Range Test was used to compare
the treatment means for the variables.
RESULTS AND DISCUSSION
Feed intake
The mean dry-matter intake of the test roughages, total dry-
matter intake and metabol isable energy intake by the lactating
cows are presented in Table 1.
194
Table1.Intakofdietarycomponents,to lry-matterintak
andMEintake.
Treatments
0.11 0.11 2.44
4.92C
8.62aCNS
81.34C
3.11b 8.10b 75.49b
EietarycomponentsNaOH"dip"-treatedUntrea dEleph n00E
maizestoververgrass
Testroughage(kg/cowday)Z.&r
►_Totaldry-m tterintake(kg/cow/day)8.44
wTotalMEintake(e)( JME/cow/day)86.50
(e)=MEEx0.81MAFF,19750n rgydig.
Eoefficientfromshe pexperim .
Meanswithinrowthdifferentlet ersarsignifica tly
different(P<0.01).
NS=notsignificant(P<0.55).
Mean dry-matter intake of the test roughages
The mean dry-matter intake of the elephant grass, sodium
hydroxide "dip"- treated and untreated maize stovers and their
levels of significance are shown in Table 1 and illustrated in
Figure 1. The dry-matter intake of elephant grass was
significantly higher (P<0.01) than that of treated and
untreated maize stovers. The intake between the maize stovers
also differed by 0.76 kg DM/cow/day, representing an increase
of 24.44 per cent in favour of the sodium hydroxide "dip"-
treated maize stover. This difference was also significant
(P<0.01) and falls within the range reported elsewhere
(Greenhalgh et al, 1976; Kristensen, 1981). The intake of
sodium hydroxide "dip" treated maize stover in this study was
found to be higher than the level reported by Sundstol (1981).
However, it was difficult to raise the intake above 4.5 kg
DM/cow/day and the maximum arrived at was 4.23 kg DM/cow/day
during the pre-experimental period. This confirms the
suggestion by Owen (1981) that sodium hydroxide "dip"-treated
maize stover can only play a role of supplement, replacer or
partial replacer of the other roughages for lactating dairy
cows.
Mean total dry-matter intake by lactating dairy cows
Cows had a higher total dry-matter intake of elephant grass-
based diets (8.62 kg DM/cow/day) than the sodium hydroxide
"dip"-treated maize stover (8.44 kg DM/cow/day) and untreated
maize stover (8.10 kg DM/cow/day) based diets. The difference
in total dry-matter intake between elephant grass and NaOH
"dip"- treated maize stover based diets was not significant
(P<0.05), but the differences between these diets and the
untreated maize stover-based diet were significant (P<0.01).
196
The mean total dry-matter intake of elephant grass-based
diet in this study was similar to the total dry-matter intake
reported by Combellas and Martinez (1982). These authors used
elephant grass roughage with supplementation of 3 kg
concentrate.
Metabolisable energy (ME) intake
Table 1 shows metabolisable energy (ME) intake of 86.50, 75.49
and 81.34 MJME/cow/day for treated maize stover, untreated
maize stover and elephant grass-based diets, respectively. The
ME intake of the sodium hydroxide "dip"- treated maize stover-
based diet was significantly higher (P<0.01) than that of the
untreated maize stover-based diet. Similarly the ME intake of
the elephant grass-based diet was higher (P<0.05) than the
untreated maize stover-based diet. Difference in ME intake
between sodium hydroxide "dip"- treated maize stover and
elephant grass-based diets were also significant (P<0.05).
This study indicated that the sodium hydroxide "dip"-
treated maize stover-based diet could supply ME better than
fresh elephant grass-based diet.
Treatment effects of milk yield and 4% FCM
The mean daily actual milk yield and 4% FCM are presented in
Table 2.
197
18
o
O
If
■a v
—• a
a> t>
•— l_
>. «
a &
E n
ii
it c
C X
ID u
01 u-
■6.
in
0) io
l_
Uj CTI
l_
0>>18 O
V U)
1D
(1) 91
l_ N
C 1
en
z
CO«~ *~
d d
T.
o
n! CK
-S
a. o
ID
2 E
•- o
E o
U K
S
l_
•5
^ 01
S IS
d 5
v
0. £
s ?
2 &
198
Actual mi Ik yield
The actual milk yields were 7.7, 7.6, 7.7 kg/cow/day for
treated maize stover, untreated maize stover and elephant
grass-based diets respectively, and the differences were non
significant (P<0.05).
There was a general decline in actual milk yield with
advancing lactation, particularly with the sodium hydroxide
"dip"-treated maize stover and untreated maize stover-based
diets. The decline was however small from the first to second
period than from the second to third period as illustrated in
Figure 2. The fall in actual milk yield for the elephant
grass-based diet was inconsistent. There was a decline in the
second period and a sharp rise in the third period.
This trend was also reflected in the ME intake. The actual
milk yield recorded in this study from the elephant grass-based
diet was similar to the yield reported by Combellas and
Martinez (1982).
4% fat-corrected milk (FCM)
The 4 percent fat-corrected milk yield was highest (9.5
kg/cow/day) with sodium hydroxide "dip"-treated maize stover-
based diet than untreated maize stover (8.8 kg/cow/day) and
elephant grass (9.3 kg/cow/day) -based diets. There was no
significant difference in 4 percent fat-corrected milk yield
between treated maize stover and elephant grass-based diets
(P<0.05). However each of these two treatments produced
significantly more 4 percent fat-corrected milk (P<0.1) than
the untreated maize stover-based diet.
199
In this study it shows that sodium hydroxide "dip"-
treated maize stover was more efficiently utilized for milk
production than elephant grass as less dry-matter consumed
resulted in more FCM. Improved performance with alkal i -treated
roughages has also been reported in other studies (Greenhalgh
et al, 1976).
Fat and protein content in milk
Table 3 shows fat and protein content as influenced by
treatments.
Table 3. Fat and protein content in milk.
Treatments
Milk chemical NaOH "dip"-treated Untreated Elephant
composition maize stover maize stover grass SED
(g/100g)
Fat
Crude protein
5.60c
3.44£
5.311
3.35£
5.43abNS
3.43a
0.10
0.65NS
NS = not significant (P<0.05).
Means within a row with different letters are significantly
different (P<0.05).
Fat content
The mean fat content (g/100g) in milk ranged between 5.60-
5.43g/100g. The sodium hydroxide "dip"-treated maize stover-
based diet produced a higher milk fat content (P<0.05) than
u-treated maize stover. Similar findings were reported
200
elsewhere (Greenhalgh et aI, 1976; Kristensen, 1981). The
higher fat content produced by the sodium hydroxide "dip"-
treated maize stover-based diet was a reflection of an improved
crude fibre digestibility and hence the production of more
acetic acid in the rumen.
Protein content
The mean protein contents were 3.44, 3.33, 3.34 g/100g for
sodium hydroxide "dip" -treated maize stover, untreated maize
stover and elephant grass-based diets, respectively. No
significant differences were found between the treatments
(P<0.05). The values obtained in this study are within the
range of documented information (Campbell and Marshall, 1975).
CONCLUSION
Inherent constraints of low protein, energy and mineral
availability in crop residues like maize stover cause
inefficient use of these materials. Alkali treatment as well
as supplementation of different nutrient could be useful in
utilizing these crop residues as alternative feed during dry
seasons for milk production. This study emphasises the
usefulness of these materials.
REFERENCES
AOAC (Association of Official Analytical Chemists). 1965.
Official methods of analysis. (10th ed.). AOAC,
Washington, D.C.
British Standard Institution. 1965. The Gerber method of fat
analysis in milk and milk products. BS 696 1955. Part 2
revised. British Standard Institution, London.
201
Campbell, J.R. and Marshall, R.T. 1975. The science of
providing milk for man. McGraw-Hill Book Company, New
York, London. 801 pp.
Combellas, J. and Martinez, N. 1982. Intake and milk
production in cows fed chopped elephant grass (Pennisetum
purpureum) and concentrate. Tropical Animal Production
7: 57-60.
Greenhalgh, J.F.D.; Pirie, R. and Reid, G.W. 1976. Alkali
treated barley straw in complete diets for lambs and
dairy cows. Animal Production 22 : 159 (Abstr).
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 Technology 4:97-107.
Kategile, J. A 1982. Utilization of low quality roughages
with or without NaOH treatment. In: B. Kiflewahid, G.R.
Potts and R.M. Drysdale (eds.), By-production
utilization for animal production. Proceedings of
Workshop on Applied Research held in Nairobi, Kenya,
26-30 September 1982. pp. 37-48.
Kristensen, V.F. 1981. Use of alkali treated straw in rations
for dairy cows, beef cattle and buffaloes. In: J. A.
Kategile, A.N. Said and F. Sundstol (eds.),
Utilization of low quality roughages in Africa. A
workshop held at Arusha, Tanzania, 18-22 January 1981.
Lamport Gilbert Printers Ltd, Reading, England. pp. 91-
106.
MAAF. 1975. Energy allowances and feeding for ruminants.
Technical Bulletin 33. Her Majesty's Stationery Office,
London.
Maynard, L.A.; Loosli, J.K.; Hintz, H.F. and Warner, R.G. 1979.
Animal nutrition. 7th edition. Tata MacGraw-Hill
Publishing Company Limited, New Delhi, pp. 602.
202
Owen, E. 1981. Use of alkali treated low quality roughage to
sheep and goats. In: J.A. Kategile, A.N. Said and F.
Sundstol (eds.), Utilization of low quality roughages in
Africa. A workshop held in Arusha, Tanzania, 18-22
January 1981. Lamport Gilbert Printers Ltd., Reading,
England. pp. 131-150.
Snedecor, G.W. and Cochran, W.G. 1967. Statistical methods.
6th edition. The Iowa State University Press, Ames,
Iowa, U.S.A. 593 pp.
Sundstol, F. 1981. Methods for treatments of low quality
roughages. In: J. A. Kategile, A.N. Said and F. Sundstol
(eds.). Utilization of low quality roughages in Africa.
A workshop held at Arusha, Tanzania, 18-22 January 1981.
Lamport Gilbert Printers Ltd., Reading, England. pp. 61-
80.
Urio, N.A. 1981. Alkali treatment of roughages and energy
utilization of treated roughages fed to sheep and goats.
Ph.D. thesis, University of Dar-es-Salaam, Tanzania.
203
THE FEEDING VALUE OF SOME AGRO- I NDUSTRI AL BY-PRODUCTS FOR
BEEF CATTLE AT BAMBUI CENTRE
T. Beramgoto
Institute of Animal Research
Bambui Experimental Station
P.O.Box 80, Bamenda, Cameroon
ABSTRACT
An investigation of the use of agricultural by-products as
cattle feed was conducted at Bambui Experimental Station.
Banana forage fed ad I ibi tum with mineral supplementation
supported maintenance in beef cattle and daily of 9 g for 3
months. Intensive fattening rations with various levels of
maize stover, palm kernel cake, cottonseed cake and rice
polishing also give promising results. The ration with 34%
palm kernel cake was associated with the highest net revenue of
49,735 CFA per head while that with the highest proportion of
cottonseed cake corresponded to the lowest but substantial
profit of 27,997 CFA per animal. Banana forage and maize
stover cannot be used by local smallholders due to the cost of
collection, transport and processing. Integrated crop and
livestock farming is recommended as a solution.
Importing cottonseed cake from the North for use as
cattle feed in the North West Province was uneconomical. The
introduction of a commercial feed lot in Douala to take
advantage of low transport cost by train may be profitable.
Further studies to determine economical location of feedlot and
for better ration formulation based on agricultural by-products
available in the North West Province are to be considered.
Grass (Brachiaria ruzi ziensis) hay and legume (Stylosanthes
guyanensis) hay produced locally are to be evaluated as dry
season cattle feeds in the North West Province.
INTRODUCTION
The use of agro- industrial by-products as animal feed has been
a common practice for decades in industrialised nations where
204
millions of tons are produced each year. This development has
been the result of intensified research activities designed to
find efficient methods of recycling agricultural waste.
Chemical (soaking in NaOH) and mechanical, pelleting and
grinding processing techniques were devised for improving
nutritional values of the poorest by-products such as cereal
straws (El Hag and Kurdi, 1986).
With the ever-growing world population pressure, making
competition between grazing land and crop land a preoccupying
reality for political leaders, developing country such as
Cameroon have been attempting to adopt this relatively old
technology for better management of their agricultural
resources. The unavailability of grass during the dry season
in areas of the country gives even more importance to
agricultural by-products as sources of nutrients for livestock
in this period.
In Cameroon, the relative abundance of farm residues
(rice bran, rice straw, maize stover, maize cobs etc) in
Northern as well as Western provinces of the country (MESRES-
IRZ Bambui Centre 1985/86; Fomunyam and Meffeja, 1986), offers
a unique opportunity for fast improvement of animal production.
According to Fomunyam (1984), the Northwest and Western
provinces of Cameroon alone produce about 3080 tons of maize
stover, maize cobs, rice straws and rice bran annually.
The Cameroon Institute of Animal Research (IRZ), the
main public institution with the mission to develop animal
resources in the country, has been trying to take advantage of
this situation. It has been making serious research efforts to
determine the feeding value of locally available agricultural
by-products. The Bambui Animal Research Centre, responsible
for the improvement of beef and dairy cattle production in the
Western Highlands of the country, one of two main zones of IRZ
operations, has been particularly active in this area with some
success.
The main objective of this paper is to discuss the
constraints to the practical application of positive results
205
obtained by research workers of the Bambui Centre. The
specific goals of this study are the following:
- to review research activities on agricultural by
products;
- to study physical constraints to practical use of
these by-products by local farmers; and
- to propose alternative strategies to overcome the
identified obstacles.
MATERIALS AND METHODS
The feeding value of agricultural by-products was evaluated
primarily in an attempt to design a dry season feeding package
based on the use of farm residues. Since the management of
animal production is location-specific, it is important to give
a brief geographic description of the study area to
substantiate the underlying concerns.
Location of the study area
The Bambui Experimental Station is located on the high lava
plateau of the North West Province of Cameroon about 23 km N.E.
of Bamenda. It is situated at latitude 6 N and longitude 10
15'E. This area experiences the dry and rainy seasons as any
other tropical region, but with very peculiar lengths. The dry
season lasts from mid-November to mid-March i.e. 4 months. The
rainy season starts in mid-March and ends in mid-November (8
months), bringing 2310 mm. The abundant rainfall, combined with
a rich volcanic soil, makes the Western Highlands of Cameroon
most favourable for agriculture. Most African countries will
envy the cool temperatures of Bambui (minimum of 0-15 C,
maximum of 24.6 C and monthly average of 20.2°C) and its
elevation of 1600-1980 m above sea level coupled with rich
natural savannah vegetation.
206
Review of investigations on nutritional value of major
agricultural by-products of Cameroon
Several feeding trials were conducted at Bambui Centre to
evaluate the nutritional value of locally available farm
residues. Two trials were retained because of their
interesting results and also because they made use of major
agro- industrial by-products of Cameroon.
The first trial involved the supplementation of banana
forage with cottonseed cake and/or dried leaves of Leucaena
leucocephala as protein sources. The composition of the four
diets formulated for the study is shown in Table 1.
Table 1. Diets of banana forage supplemented with cottonseed
cake and/or dried leaves of Leucaena leucocephala.
Diet
Ingredient
Banana forage ad lib. ad lib. ad lib. ad lib.
Cottonseed cake
(g/head/day) 0 750 0 500
Leucaena dried
leaves (g/head/day) 0 0 1500 500
2
Mineral mixture
(g/head/day) 10 10 10 10
1. Banana forage contains 70% pseudo-stem and 30% leaves.
2. Mineral mixture contains 50% table salt and 50% bone meal
207
A dozen young bulls of Ngaoundere and Ngaoundere crosses
averaging 300 kg of liveweight and 2 years and 6 months of age
were used. The animals were randomly divided to 4 groups which
were also randomly assigned to the four dietary treatments in a
4x4 latin square design.
Banana forage (mixture of dried pseudo-stem and leaves)
was chopped and mixed with various levels of protein supplement
as indicated in Table 1. Banana forage and water were given ad
I ibi tum. A known amount of forage was offered to each group
daily at 8:00 a.m. and the leftover was weighed the next
morning before feeding. Daily feed consumption was recorded.
The trial lasted 107 days including an adaptation period
of one week. Animals were weighed fortnightly. Data on daily
gain and feed intake were collected and analysed statistically
for diet effect. Results presented in Table 2 show that diet 3
with levels of protein and energy far above maintenance
requirements was associated with the highest daily gain. Diet
1 with protein content barely enough to meet maintenance need
of a 300 kg bull resulted in a daily gain of 8.9 g. These
results suggest that banana forage can be a good dry season
feed for cattle even unsupplemented. The fact that
supplementation with cottonseed cake alone was related to a
lower daily gain compared to using Leucaena as protein source
can be explained by the difference in energy availability
(Table 2). Using higher levels of Leucaena to supplement
banana may be recommended for intensive fattening of beef
cattle. Increasing the level of cottonseed cake might not be
economical .
208
Table 2. Effect of supplementing banana forage with cottonseed
cake and/or Leucaena on intake and growth
Diet
Parameter
Number of bulls 3 3 3 3
Initial liveweight (kg) 306.0** 298. 8a 296. 8a 302. 5a
Final liveweight (kg) 306. 6b 302. 8b 307. 8b 357. 1b
Ave. daily gain (g) 8.9C 142. 8bc 417. 42a 357. 1ab
Ave. daily feed intake
(kg DM/bull) 3.08a 3.30a 3.39a 3.55a
Ave. daily CP intake
(g/bull) 240.0 573.8 615.9 590.53
Ave. dai ly ME intake
(Meal/bull) na 2.07 3.84 2.66
Adapted from Wegad (unpublished data).
**
Means of the same row with the same superscript are not
significantly different (P > 0.05).
na = not available.
The second nutritional trial considered after reviewing
research activities on agricultural by-products at Bambui
Centre concerned intensive fattening of beef animals. The
three diets used are presented on Table 3. This experiment is
interesting because it makes use of most of the agro- industrial
by-products of Cameroon. The diets were formulated so as to
contain approximately the same level of protein (12.92%).
Twenty-seven bulls with liveweight varying between 270 and 284
kg were divided into 3 groups of 9 animals each.
209
Table 3. Intensive fattening rations with various levels of
corn stover and major agro- industrial by-products of
Cameroon.
Feedstuff
Ration
1 2 3
Corn stover (%) 20 40 80
Rice polishing (%) 40 23.5 10
Palm kernel cake (%) 34 22.5 0.0
Cottonseed cake (%) 3..5 11.5 5.5
Urea (%) 0..0 0.0 2.0
Mineral mixture (%) 2..5 2.5 2.5
CP (%) 12..92 12.9 12.96
ME (meal/kg DM) 2..887 2.57 2.41
Cost (CFA/kg)* 38..87 34.49 23.39
1US$ = 295 CFA in 1987.
The three groups were randomly assigned to the three dietary
treatments. The results shown on Table 4 indicate that corn
stover supplemented with energy feeds (rice polishing and palm
kernel cake) and a protein source (cottonseed cake) can be
profitable when used to fatten beef animals. The diet with the
highest level of palm kernel cake had the highest net return.
210
Table 4. Profitability of intensive fattening of steers using
corn stover, rice polishing, palm kernel cake and
cottonseed cake as major feed ingredients.
Ration
1 2 3
9 9 9
268.94 277.28 282.8
365.16 360.50 308.80
859 742 214
6.25 7.44 7.04
87.392..5 90.122.5 92.560..0
29.880..0 27.450.0 17.502,.0
164.340,.0 162.225.0 138.960..0
49.735 43.344 27.997
Parameter
Number of bulls
Initial weight (kg)
Final weight (kg)
Dai ly gain (g)
Daily intake (kg DM/head/day)
Purchase price
(CFA/bull)
Feed cost (CFA/f inished bull)
Sale price
(CFA/f inished bull)
Profit CFA/f inished bull
Bulls are purchased at the price of 325 CFA per kg of
liveweight. 1US$=295 CFA in 1987.
Finished bulls are sold at the price of 450 CFA per kg of
I ive- weight.
Investigating physical constraints to the efficient use of corn
stover, banana forage and agro- industrial by-products found in
Cameroon
The methodology used in this study consisted of uninformal
questioning of workers of the Centre involved in collecting,
transporting and processing of banana forage and corn stover.
Financial reports of the Centre were also reviewed to determine
the sources of supply and price of rice polishings, palm kernel
cake and cottonseed cake. Local suppliers were also
interviewed. Questions usually asked were related to sources
of supply and difficulty of acquiring, transporting and storing
the by-products. Following the interviews, the answers were
written out and studied to identify common constraints. Three
211
local suppliers of cottonseed cake, palm kernel cake and
groundnut cake were contacted.
RESULTS AND DISCUSSION
Physical constraints of using banana forage and corn stover as
beef cattle feed at Bambui Centre
Banana forage and corn stover were proven valuable as cattle
feed by researchers at Bambui Centre. However their practical
use by local cattlemen remains a problem. Generally these are
not crop growers and they do not have proper means of
collecting and transporting agricultural residues. For
instance, purchasing corn stover from Bali, 45 km away, to feed
to animals in Bambui, cost 28 CFA/kg if the farmer provides
labour for collection and if one uses his own 2-ton vehicle and
buys 40 litres of fuel at 150 CFA/litre (Table 5). Even if the
cattleman can afford to acquire the corn stover, he still has
to chop it which is very tedious. The mechanical chopper as
used at the Centre is not at the reach of smallholders.
Table 5. Cost of acquiring corn stover and banana forage at
Bambui Centre.
Parameter Corn stover Banana forage
Supply point Bali Bambui -Bambi I i
Price 15 CFA/kg* 30 CFA/plant
Labour for collection 10 CFA/kg
** —
Transport cost 3 CFA/kg _
Total 28 CFA/kg 30 CFA/plant
1US$ = 295 CFA in 1987.
**
Transport cost is 3 CFA/kg if one uses his own 2-ton vehicle
and buys 40 litres of fuel at 150 CFA/litre.
212
Banana forage is even more expensive because a plant
which contains only 10% dry matter is sold at 30 CFA excluding
labour for collection and transport cost. Chopping banana
forage is as difficult as corn stover.
A major constraint of adopting banana forage and corn
stover is the conflict between their use as manure and their
use as cattle feed. These two by-products are very important
for improving soil fertility by local farmers who are reluctant
to sell them.
There are three alternatives for solving the above
conflict and permit the use of banana forage and corn stover as
cattle feed in the Bambui area. The first alternative requires
an agreement between the crop farmers and cattlemen who will
then exchange cattle manure and farm residues. In this case,
the problems of transport and processing remain unsolved.
The second alternative calls for a good co-operation
between the two communities. Farmers will let cattle into
their farms after harvesting their crops. This solution
eliminates processing and transport constraints.
The third alternative which requires important social
changes, is in favour of integrated crop and livestock farming.
Cattlemen have to learn cropping techniques and vice versa.
Obstacles and possibilities of using cottonseed cake as cattle
feed in Western Province of Cameroon
The value of cottonseed cake as animal feed has been recognised
for decades by many researchers (IEMVT, 1974; MESRES-IRZ, 1983-
1984; Church, 1984; MESRES- IRZ-Bambui Centre, 1985-1986). As
illustrated earlier results of research conducted under Bambui
conditions confirmed this reality. Nevertheless, many
obstacles must be overcome by local small cattlemen before they
can practically take advantage of the nutritive value of
cottonseed cake.
In Cameroon, cottonseed cake is produced in the Northern
213
cities of Maroua, Kaele and Garoua. Bambui Centre is located
at 730 km, 655 km and 540 km from Maroua, Kaele and Garoua,
respectively. One has to face many problems to transport
cottonseed cake from one of these locations to Bambui Centre.
The average cost of buying and transporting 24 tons of
cottonseed cake from Kaele to Bambui Centre by road is 95.25
CFA/kg. This includes the purchase price (3,500 CFA/bag of 60
kg), truck lease (35,000 CFA/ton), loading charge (35 CFA/bag)
and unloading charge (20 CFA/bag). Major problems related to
transport by road are the following:
- truck availability; truck lease depends on truck
availability and relationship with the truck owner;
poor road conditions between Kaele and Bambui Centre
in the rainy season;
competition between domestic and European markets where
prices are higher; and
unsteady supply due to seasonal production of cotton.
Transporting cottonseed cake by train between the two
points is even more expensive. The average cost for both
purchase and transport in this case is 100.09/CFA/kg which
includes the following components:
- purchase of cottonseed cake;
- loading in Kaele;
- truck lease from Kaele to Ngaoundere;
- unloading charge in Ngaoundere;
- train transport charge from Ngaoundere to Nkongsamba;
- loading charge in Nkongsamba;
- truck lease from Nkongsamba to Bambui Centre;
- unloading charge in Bambui.
In view of all these difficulties, using cottonseed cake
as protein supplement for beef cattle in the North West
Province is uneconomical even for a large commercial livestock
enterprise. Using it to supplement dry season feed is the most
expensive way to keep animals alive in this part of the
country.
214
CONCLUSION AND RECOMMENDATIONS
The North West Province of Cameroon has a great potential for
cattle production. However, local cattlemen have difficulties
to feed their animals through the four months of the dry season
due to lack of forage in this period. Feeding trials at Bambui
Experimental Station showed that banana forage offered ad
libitum with a mineral supplement could help animals maintain
weight in the dry season and even contribute to average daily
weight gain of 9 g. Supplementing banana forage with 1500 g of
dried leaves of Leucaena leucocephala per head daily resulted
in average daily gain of 616 g and could be recommended for
intensive fattening. Daily cottonseed cake supplement of 750 g
per head was associated with a substantial weight gain of 574
g/day which did not seem economical.
An intensive fattening trial using various levels of
corn stover, rice polishings, palm kernel cake and cottonseed
cake gave promising results. The diet with the highest level
of palm kernel cake (34%) corresponded to the highest net
revenue (49,734.6 CFA per head) while the ration with the
largest proportion of corn stover led to the smallest but still
substantial profit of 27,996.7 CFA per animal.
Collecting, transporting and processing banana forage
and corn stover remain the biggest obstacles to the practical
application of these results by small cattlemen. Purchasing,
collecting and transporting 2 tons of corn stover on 45 km
could lead to a total average cost of 28 CFA/kg while one
banana plant with 10% dry matter cost 30 CFA. The best method
of eliminating these constraints is integrated crop and
livestock farming which will require some social changes since
cattlemen have to learn crop growing techniques and vice versa.
Importing cottonseed cake from Northern Cameroon for use
in fattening diets or as supplement of dry season rations in
the North West Province of the country seemed uneconomical due
to its unsteady supply and high transport cost. One plausible
solution to this situation is to build a commercial feedlot in
Douala and use rail road only to transport cottonseed cake from
215
the North. This arrangement is expected to cut down transport
cost substantially. In fact it would be interesting to study
the economical location of commercial feedlots in the future
considering the points of cattle supply and markets and also
the sources of major inputs. A further feeding trial with the
application of linear programming for better ration formulation
using agro- industrial by-products directly available in the
North West Province is being planned. The last alternative
being considered for study is the use of hay from grass
(Brachiar ia ruzi ziensis) and legume (Stylosanthes guyanensis)
produced locally.
ACKNOWEDGEMENT
I must thank Miss Eugenie Bomobiobo, secretary at Bambui Centre
for typing this article.
REFERENCES
Church, D.C. 1984. Livestock feeds and feeding. 0 and B Books,
Corvallis, Oregon, USA.
El Hag, M.G. and Omer, I. K. 1986. Prospects for efficient
utilisation of agro- industrial by-products and crop
residues for ruminant feeding in the Sudan, with emphasis
on quantification, nutritional composition, constraints
and research results. In: T.R. Preston and M.Y.
Nuwanyakpa (eds), Towards optimal feeding of agricultural
by-products to livestock in Africa. Proceedings of a
workshop held at the University of Alexandria, Egypt,
October 1985. ILCA, Addis Ababa, Ethiopia. pp. 22-32.
Fomunyam, R.T. 1984. Report on the workshop on: Consultative
guidelines for research on crop residues and agro-
industrial by-products. ILCA, Addis Ababa.
Fomunyam, R.T. and Meffeja, F. 1986. Maize stover in
maintenance diets for sheep and goats in Cameroon.
In: T.R. Preston and M.Y. Nuwanyakpa (eds), Towards
optimal feeding of agricultural by-products to livestock
in Africa. Proceedings of a workshop held at the
University of Alexandria, Egypt, October 1985. ILCA,
Addis Ababa, Ethiopia. pp. 135-139.
216
I.E.M.V.T. 1974. Studies on the Intensive Fattening of
Cameroonian Zebu Cattle in High Lava Plateau of
Bamenda.
Mbah, D.A.; Mbanya, J. and Messine, 0. 1987. Performance of
Holsteins, Jerseys and their Zebu crosses in Cameroon:
Preliminary results, (in press.)
MESRES - IRZ. 1983-1984. Annual Report. Ministere de
I 'enseignement superieur et de la recherche
scientif ique, direction generaIe, Yaounde, Cameroon.
MESRES-IRZ. Bambui Centre. 1985-1986 Annual Report. Ministere
de I 'enseignement superieur et de la recherche
scientif ique, direction generaIe, Yaounde, Cameroon.
217
MAIZE STOVER AS A FEED FOR RUMINANTS
1 2
T. Smith, C. Chakanyuka , S. Sibanda and B. Manyuchi
Department of Research and Specialist Services
Grasslands Research Station
P. Bag 3701, Marondera, Zimbabwe
ABSTRACT
Maize stover, the major crop residue in Zimbabwe, is
characterised by a low protein and high fibre content. Little
attempt has been made to improve its nutritive value. Two
experiments have been completed, the first of which considered
the effect of amount of plain untreated stover offered on
intake in both cattle and lambs. Stover offered increased from
1.5 - 3.0% of body weight with increased intake at the higher
level (P<0.05). There was little evidence of selectivity. A
supplement of protein increased intake at all ratec of offer in
lambs.
In the second experiment untreated stover was compared
with stover treated with 3, 5 or 7% urea for 5 weeks. In
cattle and lambs intakes were greatest with less than 7% urea
(P<0.05) although digestibility in lambs was greatest with
7% urea (P<0.05). These results were supported by measurements
of dry matter degradabi I i ty in cattle, using the nylon bag
technique, and j_n vi tro digestibility. The j_n vi tro study
confirmed 5 weeks as being the optimum treatment period in the
prevailing experimental conditions. Between experiments intake
was improved by coarse grinding and it is concluded that
physical aspects of collecting and feeding residues should be
considered together with alkali treatment and supplementation
in order to reduce wastage.
ARDA, Box Bw 41, Harare, Zimbabwe.
2
Dept . of Animal Science, University of Zimbabwe, Mt,
Pleasant, Harare, Zimbabwe.
218
INTRODUCTION
Crop residues are characterised by low protein and high fibre
content and this limits their nutritive value for ruminants.
Nitrogen (N) supplementation increases digestibility and
intake. (Campling, Freer and 8alch, 1962). Maximum intake of
cereal straws occurs when crude protein concentration is 66-85
g/kg dry matter (DM) (Elliott and Topps, 1963; Smith et al,
1980).
Chemical treatment of residues also increases intake and
digestibility. The benefits to be gained from alkali treatment
of residues have been reviewed by Jackson (1977) and Sundstol
(1981). Although Sundstol (1981) and Smith et al (1984) found
sodium hydroxide more effective than ammonia, the use of alkali
containing N reduces the need for protein supplementation
(Smith and Balch, 1984). Treatment with urea has been
effective in warm (Saadullah et al, 1981) but not temperate
climates (Mason and Owen, 1986; Sherwood and
Owen, 1987).
Physical treatment usually implies a reduction of
particle size. Greenhalgh and Wainman (1972) demonstrated that
although intake was improved, a reduction in digestibility was
often associated with physical treatment. Walker (1984)
concluded that a combination of chemical and physical
treatments would be most effective in upgrading crop residues.
The role of crop residues in ruminant nutrition in
Zimbabwe was summarised by Sibanda (1986). Maize stover is the
principal residue and is either grazed ui situ or removed from
the land prior to feeding. There has been no attempt to
upgrade residues although dry season feed is in short supply.
In this study the effects of amount of stover on offer, protein
supplement and level and period of urea treatment on nutritive
value of maize stover in cattle and sheep were investigated.
219
Experimental procedure and results
Two experiments were conducted. In the first the effects of
varying the amount of maize stover on dry-matter intake (DMI)
in cattle and sheep were measured. In the second maize stover
was treated with urea and changes in digestibility and intake
were assessed by j_n vivo and j_n vitro techniques.
The stover (Var SR 52) came from a single batch produced
on the station. After harvesting the grain and cob the residue
was rotor slashed and baled. In Experiment 1, it was fed
direct from the bale to cattle and coarse ground (14 mm screen)
when fed to sheep. For Experiment 2, the stover was subdivided
into four stacks. One stack was left untreated, the remaining
stacks being treated with 3,5 or 7% urea (w/w) and kept wrapped
in clear plastic sheeting for 5 weeks. The- urea was added as a
solution so that regardless of urea concentration 20X of water
was added to the stover (w/w). The untreated stover was kept
dry to avoid the risk of mould. Small amounts of the stover
were treated as above and sealed in plastic bags for 1, 3 or 5
weeks. Treatment dates were staggered so that the stacks and
bags were all opened on the same day. Composition of the
stover and the climatic conditions during the treatment period
are given in Table 1.
Experiment 1
Twenty steers (initial liveweight 224 kg) and 20 lambs (initial
liveweight 37 kg) were each ranked according to liveweight and
then randomised to give five replicates of four treatments.
The treatments were defined as amount of stover offered (1.5;
2.0; 2.5; 3.0% stover DM per day of initial body weight). No
other feeds were given except where stated. All animals were
individually penned with refusals being taken and fresh feed
offered dai ly.
220
Table 1. Composition of maize stover fed to cattle and sheep
during Experiments 1 and 2 and ambient temperature
(°C) and relative humidity (%) di
period of stover for Experiment 2,
uring the treatment
DM DM basis g/kg DM
g/kg Nitrogen Acid-detergent fibre Ash
Expt. 1. Cattle 936 58 431 45
Sheep 933
Expt. 2. 0% urea 926 58 431 45
3% urea 913 180 465 49
5% urea 905 218 443 45
7% urea 907 324 458 47
Maximum Mini mum
Temperature (°C) September 25.5 10.1
(range 19.6 - 29.6) (range 4.0 -14.6)
October 25.6 12.0
(range 18.5 - 31.0) (range 8 -15.7)
* +
Humidity (%) September 79.3 28.1
(range 59 - 100) (range 13 -62)
October 86.6 39.9*
(range 61 - 100) (range 20 -85)
Measured at 6.00 h
Measured at 14.00 h
221
The steers were grazed on stover for 10 days and were
then penned for 50 days. Intake was recorded over the last 30
days. Both total intake (kg DM/d) and g DM/kg W ' /d were in
the order 1.5% = 2.0 and 2.5% = 3.0% (P<0.05> (Table 2).
Chemical composition of refusals was similar to that of the
fresh stover.
*
Table 2. Dry-matter intake of stover , in cattle and lambs, as
affected by the amount offered (Stover DM kg/d as %
I i veweight ) .
Stover allocation : 1.5 2.0 2.5 3.0 SE
Cattle :
Total intake (kg DM/d) 2.17 2.17 2.56 2.58 0.07
Intake g DM/kg W0.73 41.5 42.9 49.9 49.0 1.56
Refusals as % of
amount offered 31.8 48.5 51.2 59.5
Sheep : a) No protein
Total intake g DM/d 325 294 313 400 29.1
Intake, g DM/kg °-73 23.2 21.4 22.3 29.1 1.91
Refusals as % of
amount offered 41.9 60.6 66.5 64.3
b) With protein
Total intake, g DM/d 376 400 354 493 37.4
Intake, g DM/kg W °-73 26.6 29.4 25.3 36.1 2.52
Refusals as % of
amount offered 32.8 46.4 62.1 56.0
Values shown refer to stover intake alone.
The protein supplement (270 g DM/d) was eaten by all sheep.
222
Sheep were fed the stover for 28 days with intakes being
measured over the last 7 days. Following this all lambs
received 270 g DM/d of a protein (15. 0% CP) concentrate and the
same stover allocation. After a further 14 days, intake was
again measured for 7 days.
At the start of the second period one lamb died from a
condition unrelated to the experiment and a missing plot value
for intake was calculated (Snedecor, 1956). Intake in both
measurement periods was greatest at the 3% rate of offer (Table
2). When the periods were combined total DMI of stover and DMI
g/kg W * were significantly increased at the 3% rate of offer
(P<0.05). Between the first and second measurement periods
mean intake increased by 71+16.1 g DM/d (P<0.01). This last
difference is probably attributable to the supplement of
protein fed in the second period. Changes in the composition
of the refusals were small, acid-detergent fibre being lowest
at the 3% level of offer (1.5%, 3.0% = 59.9%, 58.1%) and in
vitro DM digestibility highest at the 2.5% level (1.5%, 2.5% =
0.18, 0.24%).
Experiment 2
In this experiment estimates of the nutritive value of urea
treated maize stover were made using steers, lambs and j_n vi tro
digestibility (Til ley and Terry, 1963).
In order to estimate the pattern of degradabi I i ty (dg)
of the stover and measure DMI in steers, 12 animals were
individually fed (8 kg fresh stover/d) to appetite on milled
stover which had been treated with either 0,3,5 or 7% urea. No
other feeds were offered. After a 20-day adaptation period 10
nylon bags, each containing 5 g of the appropriate dietary
stover, were inserted into the rumen of each steer. Two of the
bags were withdrawn after 12, 24, 48, 72 and 96 h respectively
in order to measure DM loss. Estimates of the dg of stover DM
were made using a modification of the non- linear model (P = a ♦
b (1 - e )) proposed by Orskov and McDonald (1979). The
223
degradabi I i ty of dry matter increased with the level of urea
treatment and nitrogen in the treated stover was highly and
rapidly degraded (Table 3).
Table 3. Dry-matter (DM) and nitrogen (N) loss (%) from maize
stover treated with 0, 3, 5 and 7 percent urea
incubated in nylon bags in the rumen of steers.
% Urea levels Fitted constants for DM and N degradation (%)
- ct
model P= a+b (1-e ) Incubation time (h)
12 24 48 72 96
DM 10.4 59.8 -0.02 25.3 37.1 50.9 61.5 64.9
N 41.9 58.1 -0.006 44.0 52.9 55.7 65.5 66.2
DM 17.1 58.5 -0.02 29.4 41.2 53.2 62.1 68.3
N 81.3 5.8 -0.03 83.2 84.8 85.7 86.8 86.9
DM 14.4 66.8 -0.02 28.4 37.8 55.6 62.8 70.2
N 83.0 7.2 -0.08 87.5 89.2 90.0 89.7 90.6
DM 14.2 60.3 -0.03 31.5 43.1 58.4 65.6 72.8
N 90.0 4.8 -0.04 91.6 93.1 93.9 94.0 95.0
Daily dry-matter intake, measured over the last 10 days
of the trial, for the 0, 3, 5 and 7% urea treatments was
respectively: 3.99, 5.72, 4.97, 4.27+0.245 kg/d; 51.6, 66.9,
55.5+1.96 kg kg W0,73.
Digestibility and intake of the stovers was also
measured using 16 lambs, ranked according to initial liveweight
(mean 44 kg) and then randomised to the four treatments.
Twenty-one days of adaptation to the diet was followed by 7
days measurement of intake and then a further 7 days of intake
and digestibility measurements.
224
Intake was similar during the two measurement periods
and the data presented are for the 14 days. All the treated
stovers were eaten more readily than the control (P<0.05), the
greatest intake following treatment with 5X urea (Table 4).
Digestibilities of dry matter (DM), organic matter (OM) and
acid-detergent fibre (ADF) are given in Table 4 with the
differences between OX and 7% significant at P<0.05 (Table 4).
Table 4. Intake and digestibility of maize stover, either
untreated or treated with 3, 5 or 7X urea, offered to
lambs.
XUrea
0 3 5 7 SE
Intake : g DM/d 437 658 698 583 27.4
g DM/kg W01 73/d 28.3 40.9 44.8 37.4 2.01
OM g/d 418 626 667 556 26.0
D igest ibi l i ty : DM 0.458 0.478 0.535 0.584 0.0240
OM 0.476 0.491 0.552 0.597 0.0230
ADF 0.549 0.524 0.604 0.646 0.0202
In vi tro digestibility of DM was greatest after 5X
treatment with urea and 5 weeks sealed in plastic. An
incubation time of 72 h gave higher values than 48 h.
Digestibility of acid-detergent fibre was not improved by
Lengthening the period sealed from one to five weeks but was by
the inclusion of urea. Incubation time was 48 h (Table 5).
225
►_
Table 5. In vi tro digestibility of maize stover before and
after treatment with urea.
DM
ADF
Time of Time of
X urea treatment
treatment incubation 3 5 7
7d 48 h 0.46 0.47 0.47
72 h 0.52 0.51 0.52
21d 48 h 0.51 0.53 0.47
72 h 0.55 0.57 0.53
35d 48 h 0.53 0.52 0.50
72 h 0.56
OX urea
0.58
■ 0.46
0.57
7d 48 h 0.49 0.50 0.44
21d 48 h 0.52 0.50 0.50
35d 48 h 0.51 0.46 0.46
0 urea = 0.444
DISCUSSION
Treatment of roughage is undertaken to increase intake and
digestibility. In the two experiments reported intake was
increased by varying the amount of stover offered, feeding
protein as a supplement, treatment with urea and by altering
the physical form.
Increased intake through increasing the amount of stover
offered supports the findings of Wahed and Owen (1986). They
found increasing the refusal level of barley straw from 20 to
50X increased
intake in goats by 33X. In Experiment 1 increasing the refusal
rate from 31 to 59X increased intake by 19X in cattle. With
lambs the refusal rate increased from 42 to 64X of that offered
226
i
and intake increased 24%. With the high protein concentrate,
fed at 21 g DM/kg W ' , refusal rate increased from 32 - 56%
of that offered (the amount of stover offered was constant in
both periods of the trial with lambs) and intake rose 31%. The
overall effect of the protein supplement was to increase stover
intake by 23%. The apparent lack of selective feeding, as
measured by changes in refusals, probably reflects to some
extent the difficulty of sub-sampling a stover with widely
divergent components.
It is probable that the higher rates of stover offered
were less than those confronting cattle grazing fresh stover.
For maximum utilisation maize stover should be collected,
rather than grazed in situ. and consideration given to
chemically treating refusals (Wahed and Owen, 1987). To
minimise wastage troughs permitting little or no spillage
should be provided. Trampled or excreta-contaminated stover is
of no further use as a feed.
There were differences in DMI between steers receiving
the lowest rate of feeding in Experiment 1 and those on control
in Experiment 2 (41.5 vs 51.6 g DMI/d/kg W * respectively).
The amount offered in Experiment 2 (92.5 g/kgW " ) was within
the range offered in Experiment 1 (60.7-122.9 g/kgW " ). In
the first experiment stover was fed from the bale and in the
second it was coarse-milled. Reduction of particle size is
known to increase intake of roughages (Nicholson, 1984). The
effects of coarse chopping (probably by a hand-operated machine
such as a chaff-cutter) should be investigated.
Urea treatment of stover was also beneficial to intake
in both cattle and sheep, confirming the responses reported by
Saadullah et al (1981). Sheep ate less than steers but urea
treatment stimulated intake to a greater extent. With both
species peak intake was achieved with less than 7% urea.
Digestibility of DM and OM measured in lambs increased
with increasing levels of urea treatment. This response would
have been a combination of the effect of alkali on the cell
wall of the stover and the effect of N on fibre digestion and
227
microbial protein synthesis in the rumen (Preston and Leng,
1984). The improvement in the digestibility of DM in the rumen
(Table 3) following urea treatment confirms this pattern of
response since it is envisaged that over 80% of digested OM is
apparently digested in the rumen (Grigera-Naon, 1985). Urea
treatment boosted the N content of the stovers (Table 1), the
high digestibility of urea being reflected in the rapid and
large loss of N in the treated stovers.
Increases in digestibility measured |n vitro were not as
great as those measured in lambs. Rumen liquor was collected
from sheep fed hay and the intention to repeat the test using
sheep fed stover as donors had to be dropped. However the
results indicate that 5% urea left sealed for 5 weeks was the
optimum in the prevailing conditions (Table 1).
The relative importance of intake and digestibility can
be shown by considering the control and 5% urea treatments in
Experiment 2 (Table 3). The intake of digestible OM (DOMI)
were 201 and 361 g/d respectively. If intake had increased
without a change in digestibility the DOMI would have been
raised from 201 to 303 g/d. Therefore, 70% of the total
increase came from raised intake and 30% from an improvement in
digestibility. This represents a change in metabol isable
energy intake from 50% of maintenance to maintenance (MAFF,
1975).
Factors affecting the economics of treating residues
include : the availability and or cost of alternative feeds;
the nutritive value of the untreated material and the degree of
improvement obtained (Smith & Baleh, 1984). Where feed is
limited the slaughter value before and after the feeding period
should be considered. Plastic sheeting is expensive and cheap
methods of ensiling should be sought. Urea is not always
available. This study confirms that the physical aspects of
handling and presenting the stover to the animal should be
considered together with supplementation and alkali treatment.
228
ACKNOWLEDGEMENTS
Ue are grateful to E. Rusike, S. Mikayiri, R. Chiwara and L.
Svisvah and their staff for care of the animals and chemical
analysis.
REFERENCES
Campling, R.C.; Freer, M. and Balch, C.C. 1962. Factors
affecting the voluntary intake of food by cows. 3.
The effect of urea on the voluntary intake of oat
straw. British Journal of Nutrition 16: 115 - 124.
Elliott, R.C. and Topps, J.C. 1963. Voluntary intake for low
protein diets by sheep. Animal Production 5: 269 - 276.
Greenhalgh, J.F.D. and Wainman, F.W. 1972. The nutritive value
of processed roughages for fattening cattle and sheep.
Proceedings of the British Society of Animal Production.
pp. 61-72.
Grigera-Naon, J.J. 1985. The influence of digestion of alkali
treated winter barley straw on its utilization by growing
cattle. PhD thesis, University of Reading, Reading, UK.
Jackson, M.G. 1977. Review article: The alkali treatment of
straws. Animal Feed Science and Technology 2: 105 - 130.
MAFF (Ministry of Agriculture, Fisheries and Food). 1975.
Technical Bulletin No. 33. HMSO, London.
Mason, V.C. and Owen, E. 1986. Urea versus ammonia for
upgrading graminaceous materials. In: T.R. Preston
and M.Y. Nuwanyakpa (editors), Towards optimal feeding
of agricultural by-products to livestock in Africa.
Proceedings of a workshop held at the University of
Alexandria, Egypt, October 1985. ILCA, Addis Ababa. pp.
50 - 54.
Nicholson, J.W.G. 1984. Digestibility, nutritive value and
feed intake. In: F. Sundstol and E. Owen (editors),
Straw and other fibrous by-products as feed.
Elsevier, Amsterdam. pp. 340 - 372.
Orskov, E.R. and McDonald, I. 1979. The estimation of protein
degradabi I ity in the rumen from incubation measurements
weighted according to rate of passage. Journal of
Agricultural Science, Cambridge 92: 499 - 503.
229
Preston, T.R. and Leng, R.A. 1984. Supplementation of diets
based on fibrous residues and by-products. In: F.
Sundstol and E. Owen (editors), Straw and other
fibrous by-products as feed. Elsevier, Amsterdam. pp.
373 - 413.
Saadullah, M.; Hague, A.M. and Dolberg, F. 1981. Practical
methods for chemical treatment of rice straw for
ruminant feeding in Bangladesh. In: J. A. Kategile,
A.N. Said and F. Sundstol (editors), Utilization of
low quality roughages in Africa. AUN-Agricultural
Development Report 1, Aas, Norway. pp. 85-89.
Sherwood, R.P. and Owen, E. 1986. The comparative
effectiveness of urea and ammonia for improvement of
nutritive value of straw. Animal Production 42: 436
Abstr.
Sibanda, S. 1986. The use of crop residues in livestock
production systems in the communal areas of Zimbabwe.
In: T.R. Preston and M.Y. Nuwanyakpa (editors),
Towards optimal feeding of agricultural by-products to
livestock in Africa. Proceedings of a workshop held at
the University of Alexandria, Egypt, October 1985. ILCA,
Addis Ababa. pp. 140 - 144.
Smith, T. and Balch, C.C. 1984. Implications of a more
widespread use of straw and other fibrous by-products
as feed. In : F. Sundstol and E. Owen (editors),
Straw and other fibrous by-products as feed. Elsevier,
Amsterdam. pp. 575 - 604.
Smith, T.; Broster, V.J. and Hill, R.E. 1980. A comparison of
sources of supplementary nitrogen for young cattle
receiving fibre-rich diets. Journal of Agricultural
Science, Cambridge 95: 687-695.
Smith, T.; Grigera-Naon, J.J.; Broster, W.H. and Siviter, J.W.
1984. Ammonia versus sodium hydroxide treatment
of straw for growing cattle. Animal Feed Science and
Technology 10: 189-197.
Snedecor, G.W. 1956. Statistical methods applied to
experiments in agriculture and biology. 5th edition.
Iowa State University Press, Iowa.
230
Sundstol, F. 1981. Methods for treatment of low quality
roughages. In: J. A. Kategile, A.N. Said and F.
Sundstol (editors). Utilization of low quality
roughages in Africa. AUN- Agricultural Development
Report 1, Aas, Norway. pp. 61 - 80.
Til ley, J.M.A. and Terry, R.A. 1963. A two stage technique for
the j_n vitro digestion of forage crops. Journal of
the British Grassland Society 18: 104 - 111.
Wahed, R.A. and Owen, E. 1986. The effect of amount offered on
selection and intake of barley straw by goats. Animal
Production 42: 473 Abstr.
Walker, H.G. 1984. Physical treatment. In: F. Sundstol and E.
Owen (editors), Straw and other fibrous by-products as
feed. Elsevier, Amsterdam. pp. 79-101.
231
CONSTRAINTS TO CEREAL CROP RESIDUE UTILISATION IN CENTRAL TANZANIA
M.A. Kabatange and A.J. Kitalyi
Livestock Production Research Institute
P/Bag Mpwapwa, Tanzania
ABSTRACT
The importance of crop residues in ruminant nutrition in the
long dry seasons of semi -arid areas need not be overemphasised.
In this paper the existing practices of cereal crop residue
feeding of livestock in Central Tanzania is discussed. The
physical limitations to its use are highlighted. Production
characteristics and nutritive values of three most common
cereals in the area are presented.
Stover dry matter (DM) yields of bulrush millet, sorghum
and maize were 9661+1343.0, 8244+1491.5 and 7222+479.8 kg/ha
respectively. Crude protein (CP) ranged from 3.7 to 5.4 per
cent for the different stover fractions at harvesting and from
3.1 to 4.4 per cent at mid-dry season. J_n vitro organic-matter
digestibility (IOMD) was 52.6 to 68.3 per cent at harvesting
and 46.5 to 63.5 at mid-dry season. Between harvesting and
mid-dry season, DM, CP and IOMD of the crop residues declined
by 63%, 0.6% and 4.8 per cent respectively. These figures
show that both yield and nutritive value are reduced if the
residue is left standing in the field after grain harvest.
Possible improvement strategies on crop residue utilisation are
suggested.
INTRODUCTION
Central Tanzania lies between latitude 4 and 7 S and longitude
33 and 37 E. It covers an area of about 140,000 km in the
central semi -arid plateau at an elevation of 750-1500 m above
sea level. The mean annual rainfall ranges from 400-800 mm
with high variation in amount and distribution. The
inhabitants are mainly agro-pastoral ists cultivating millets,
sorghum, maize and groundnuts as principal crops. Livestock
species kept are cattle, sheep, goats and donkeys.
232
Utilisation of cereal crop residues for livestock
feeding, though of major importance in the agropastoral system,
has not been fully exploited. The ruminant population depends
on natural grasslands for feed, particularly in the wet season.
Crop residues form an important feed component in the dry
season. In a project "Improvement of Animal Production Systems
in Central Tanzania" a study to evaluate the potential value
and constraints to utilisation of crop residues for livestock
feeding was initiated.
METHODOLOGY
Following the Farming Systems Research (FSR) approach, a
diagnostic survey was carried out from June 1985 to May 1986
(Annual Report 1985/86). In the various stages of the
diagnostic survey carried out, guidelines followed and
questions set in the formal survey aimed at understanding the
existing use and management of crop residues. In the following
cropping season (1986/87), crop residue production and
utilisation was monitored.
Crop residues of the most commonly grown cereals,
bulrush millet, sorghum and maize were harvested from selected
farmer fields in Berege and Majeseni villages. Two samplings
were carried out, the first one at grain harvest, in early June
and the second one at mid-dry season, in early September.
2
Plant density and grain yield were estimated from 100 m plots,
whereas stover yield, stalk and leaf fractions were estimated
2
from 4 m quadrats. Dry matter (DM), crude protein (CP) and in
vitro organic-matter digestibility (IOMD) were determined on
the stover fractions.
RESULTS AND DISCUSSION
Table 1 shows farmer responses on use of crop residues for
livestock feeding. Use of legume haulms for livestock feeding
was negligible. The haulms, mainly groundnut, are produced in
the wet season when pasture availability is not critical, and
there are practical limitations to their conservation for dry
233
season feeding. Grazing in the crop fields after grain harvest
was the most common method of availing the crop residues to
livestock (61%, n = 152), though some farmers indicated not to
allow animals to graze in the crop fields after harvest, k
higher proportion of farmers in the maize zone gave the latter
response, alleging that the practice led to reduced grain
yields in subsequent crops. None of the respondents indicated
that they collect or conserve the residues for later use.
Efficient utilisation of the crop residues is limited by the
following factors; big herd sizes, long distances from crop
fields to kraals/homesteads (4.6 km), lack of transport and low
level of technology.
Table 1. Use of crop residues for livestock feeding
in the study area (per cent of responses).
Vi 1 1 age Cereal stovers Legume haulms
Banyibanyi 17 59
Majeseni 12 25
Lenjulu 20 55
Mlembule 15 40
Berege 20 40
Nghambi 17 59
Kinusi 16 31
K i s i ma 17 12
Chamtumi le 18 50
20
0
0
0
47
47
0
0
11
Study area 152 41
Source : Annual Report (1985/86).
There were wide variations in plant height and density
which may be attributed to differences in soil fertility, seed
quality, variety and husbandry practices followed. Farmers in
the same area were not following uniform recommended crop
husbandry practices as exemplified in observations whereby
234
farmers put 7-30 sorghum seeds per planting. This usually
resulted in more vegetative growth and low grain yields (Table
2).
Table 2. Grain and stover yields and harvesting indices of
bulrush millet, sorghum and maize (kg/ha).
Type of cereal Sorghum Bulrush millet Maize
Grain yield 578 + 174.5 690 + 339.2 3633 + 437.9
Stover yield at
grain harvest 8244 ♦ 1491.5 9661 ♦ 1343.0 7222 + 479.8
Harvesting index (%) 7 7 50
Stover quantity at
mid-dry season 3206 + 895.5 1579 + 527.3 4029 + 766.7
Utilisation (%) 61 84 44
Variations in grain and stover component yields were
high for all the crops studied. The quantities of millet and
sorghum crop residues were high compared to other reported
values and the corresponding harvesting indices were relatively
low (Annual Report, 1983/84; Powell, 1986). This may be due to
the practice of planting many seeds resulting into more
vegetative growth. High variations in stover yields are common
in traditional farms due to differences in management
practices. Values ranging from 0.6 to 10 tons/ha have been
reported (Annual Report, 1983/84). Loss in stover during the
mid-dry season was high, particularly with millet and sorghum
stover. The higher loss in these crops could be due to
exposure to grazing on these fields than in the maize fields.
It had been noted earlier that some farmers, particularly those
in the maize growing zone, did not allow livestock into their
fields. However, figures on utilisation are to be taken with
caution because not all crop residue loss was due to grazing.
Losses due to wind shatter and by termites might have been
substantial but were not measured. Further investigation to
quantify such losses is needed.
235
Crude protein and digestibility of crop residues are
important indicators of their nutritive value and these are
summarised in Table 3.
The cereal crop residues investigated showed that CP
values ranged from 3.7 to 5.4 per cent at harvesting and from
3.1 to 4.4 per cent at mid-dry season. In both periods the
protein content was marginal -to-deficient and not adequate for
ruminal microbial breakdown of ingested forage. Values
obtained for CP are lower compared to a study carried out in
Botswana (Annual Report, 1983/84) probably because there was no
fertiliser use in this area. The IOMD values were high for the
leaf fractions compared to the stalk or whole stover. Similar
trends have been observed by other workers (Powell, 1986;
Annual Report, 1983/84). Maize stovers had the highest IOMD
followed by sorghum and millet in decreasing order. A decline
in crude protein content and digestibility of the stover
fractions as the dry season advanced was noted. In general
there was a decline of 0.6 and 4.8 per cent in CP and IOMD,
respectively.
Table 3. Crude protein and IOMD of bulrush millet, sorghum and
maize stover fractions.
At h
CP%
arvest ing
I0MD%
At mid-dry season
Crop residue CP% I0MD%
Sorghum whole stover 5.0 60.3 3.8 52.7
Sorghum stalk 3.7 56.6 4.2 54.1
Sorghum leaf 5.4 62.8 4.4 58.5
Bulrush millet whole stover 4.4 56.0 4.0 48.3
Bulrush millet stalk 4.4 52.6 3.6 46.5
Bulrush millet leaf 4.5 63.2 4.3 54.1
Maize whole stover 3.9 63.2 3.1 60.4
Maize stalk 4.3 60.0 3.9 58.9
Maize leaf 5.0 68.3 3.6 63.5
236
CONCLUSION
The information gathered from the diagnostic survey and the
study clearly shows that there is underut i I ization and
inefficient use of the crop residues. Further, there is need
for development of technological packages on proper use of
this feed resource. Harvesting and transporting crop residues
to homesteads/kraals would be very difficult because the
materials are bulky. There is therefore a need for introducing
economical harvesting, collection, handling, transportation and
storage methods.
On improvement of the quality of crop residues,
introduction of forage legumes in the feeding system would be
the most practical. Under stall-feeding practices value of
various forage legumes such as Leucaena. Stylosanthes, and
Trifol ium species in improving the nutritive value of crop
residues have been tested (Mohamed-Saleem, 1985; Butterworth,
1986). Inclusion of a grain legume such as Dolichos lablab and
pigeon pea in the cereal fields for grazing with crop residues
after grain harvest is another possibility.
ACKNOWLEDGEMENTS
The authors wish to acknowledge the International Development
Research Centre, Canada for sponsoring them to this workshop.
Permission to attend the workshop granted by the Director
General TALIRO (Tanzanian Livestock Research Organization) is
highly appreciated. Finally we wish to express our sincere
thanks to Mr. J. Sanga for the assistance in field work, Mr.
R.A. Mwassa for the laboratory work, Mr. R. Chibindu for typing
the manuscript and colleagues at LPRI, Mpwapwa for assistance
rendered in the course of preparing this paper.
237
REFERENCES
Annual Report, 1983/84. Livestock and Range Research in
Botswana, Animal Production Research Unit; Gaborone,
Botswana.
Annual Report, 1985/86. Livestock Production Systems
(Tanzania) Project No. 3-P-84-0076 IDRC/TALIRO.
Butterworth, M.H. and Mosi, A.K. 1986. The voluntary intake
and digestibility of cereal crop residues and legume hay
for sheep. ILCA Bulletin No. 24-March 1986. ILCA,
Addis Ababa.
Mohamed-Saleem, M.A. 1985. Effect of sowing time on the grain
yield and fodder potential of sorghum undersown with
Stylo in the subhumid zone of Nigeria. Tropical
Agriculture 62 (2): 151.
Powell, J.M. 1986. Crop- I ivestock interactions in the subhumid
zone of Nigeria. In: R. Von Kaufmann, S Chater and R.
Blench (eds), Livestock systems research in Nigeria's
subhumid zone. Proceedings of the Second ILCA/NAPRI
Symposium held in Kaduna, Nigeria, 29 October - 2
November 1984. ILCA, Addis Ababa, Ethiopia.
238
GRAIN YIELD AND NUTRITIVE VALUE OF CROP RESIDUES
FROM THREE VARIETIES OF MAIZE (ZEA MAYS L) CROP
J.E. Fleischer, A.R. Barnes, B. Awumbila,
K. Amaning-Kwarteng and C.K. Tieku
Department of Animal Science
University of Ghana
Legon, Accra, Ghana
ABSTRACT
An experiment was carried out to find the grain and crop
residue yields, the nutritive value of the crop residues, the
harvest and potential utility indices of three varieties of
maize.
The maize varieties used were "Ex-Volta", Pol. -16 and
"Legon Composite 4". The maize seeds were sown after ploughing
and harrowing and fertilised with a compound fertiliser (20%N
20% Pp°5 anc* ^° K2°) and also sulphate of ammonia. All three
varieties were harvested at 65, 95 and 125 days after planting.
After harvesting, the grains were reserved. Both the grains
and crop residue were dried and weighed. The crop residue was
then analysed for crude protein content, cell wall constituents
and j_n vitro dry-matter digestibility. The harvest index of
the grain and the potential utility of the whole crop was then
calculated.
Grain yield of the three varieties, Ex-Volta, Pol. 18 and
-1
Legon Composite 4 increased from 1.04, 0.56 and 0.03 t ha at
the initial harvest to 4.87, 5.67 and 4.07 t ha at the final
harvest. On the contrary there was a significant (P< 0.01)
decline in the crop residue yield of all three varieties with
advancing growth. The crop residue:grain ratio ranged between
1.1 and 1.8:1 for the three varieties at different stages of
growth.
The various botanical fractions showed a mixed trend of
development. Whereas the leaves continuously declined with
239
advancing growth period, other parts increased or decreased
initially and later showed an opposite trend of development.
Crude protein content declined considerably with advancing
age in all three varieties and all were below 8%. Cell wall
constituent on the contrary increased with advancing age and
only the difference in ADL between Ex-Volta and Composite 4 was
significant.
In vitro dry-matter digestibility significantly (P<0.01)
declined from 80% to 64% with advancing age. No varietal
differences were observed. Harvest index of grain increased
with advancing age. Ex-Volta and Pol. -16 had a significantly
higher harvest index than Composite 4. Potential utility index
was very high (78-82%) and remained constant throughout the
growth period. No varietal differences were however observed.
INTRODUCTION
The natural grasslands constitute the main feed resources for
ruminants in many countries. However, whereas land area under
grazing has remained constant over the years, communal grazing
areas have been subjected to increasing livestock population
pressure and fluctuating rainfall (Qureshi, 1986). Thus
fluctuating feed resources continues to hamper animal
production. This means that alternative feed resources
unsuitable for human consumption but which can be valuable for
animal feeding purposes must be given more attention (L en I en
and El-Harith, 1985; Fleischer, 1986). One such feed resource
is the maize crop residue.
Maize (Zea mays L) is one of the crops widely grown by
most peasant farmers in the West African subregion. It is
estimated that grain yields range between 0.2 and 2.7 mt ha
(FAO, 1983, 1986). Powell (1985) estimated that the straw:grain
ratio of maize was 2:1. This means that twice as much crop
residue as grain which could be a very important feed for the
ruminants is produced.
240
The maize crop residue consists of various plant fractions
which have different nutrient contents and digestibilities
(Hacker and Minson, 1981; Fleischer et al, 1987). However,
not much work has been carried out on crop residue variation
between different maize varieties.
The objectives of this study therefore were to find the
grain yield, crop residue yield, nutritive value of the crop
residue, the harvest index of the crop and the potential
utility index of whole crops from different maize varieties.
MATERIALS AND METHODS
The experiment was carried out at the Department of Animal
Science, University of Ghana at Legon. The area has a subhumid
climate. The annual rainfall is 934.2 mm p. a. bimodally
distributed. The major season begins in March/April and ends
in July while the minor season is from September to November.
Temperatures are fairly uniform with a maximum and minimum of
32.5 + 1.7 and 27.7 + 1.1°C respectively. Relative humidities
are high during the rainy season, being 90-100%, but may drop
to about 40% or below during the dry season. Potential
evapotranspi ration is about 1800 mm p. a.
The soil is part of the Nyibenya-Hacho complex which is
light-textured clay and free-draining (Brammer, 1960; Hall and
Jenik, 1979).
Planting material
Three varieties of maize were used. These were "Ex-Volta",
"Pol. -16" and "Legon Composite 4" which mature at 65, 95 and
125 days, respectively, after planting. Germination tests
performed prior to sowing indicated 95% germination for all
three varieties.
Cultivation and harvesting
The experiment was laid out in a completely randomised design.
After ploughing and harrowing the field was divided into plots
241
each of 4.50 m x 3.50 m. Each plot was assigned to each
variety. Seeds of the three varieties (obtained from the Crop
Science Department,
University of Ghana, Legon) were sown at the rate of three
seeds per hill in rows. Planting distances were 0.75 m between
rows and 0.25 m within rows. Two weeks after planting, the
plants were thinned to one plant per hill, and a compound
fertilizer (20% N, 20% N P205 and 20% K20) applied at the rate
of 100 kg ha . Six weeks after planting, the field was top-
dressed with sulphate of ammonia (21% N) at the rate of 50 kg
ha . The field was hand- irrigated at regular intervals, and
weed clearing was done manually using the hoe and cutlass.
Harvesting of plants was done at 65, 95 and 125 days post-
planting. At harvest, the plants were separated into grain and
crop residues. Some of the crop residues were further
separated into leaves, leaf sheaths, stems, husk, cobs and
tassel. These plant fractions were then dried in the oven at
70 C for more than 48 hours and weighed. After weighing
samples were bulked and ground with a Wiley Mill to pass
through 1 mm sieve and stored until analyses.
The ground crop residues were analysed for crude protein
by the Kjeldhal method, for cell wall constituents by the
method of Goering and Van Soest (1970) and j_n vitro dry-matter
digestibility (IVDMD) by the method of Minson and McLeod
(1972).
The harvest and potential utility indices of the crop were
calculated as follows:
Harvest Index (HI, x = Grain yield (kg ha" ) x 100
(g)
Total above ground plant
- i
dry-matter yield (kg ha )
242
Grain yield (kg ha )+ Digestible dry-matter yield
- 1
Potential utility of crop residue (kg ha )x100
index (UI) =
-T
Total above ground plant dry-matter yield (kg ha )
RESULTS
Yield
Grain and crop residue yield of the three maize varieties at
different harvests are shown in Figure 1. Total dry-matter
yield increased with increasing growth period (P=0.01) but did
not significantly differ (P> 0.05) among varieties.
Grain yield increased significantly (P< 0.01) with
increasing growth period. At the initial harvest, the grain
yield of the three varieties Ex-Volta, Pol. -16 and Legon
Composite 4 was 1.04, 0.56 and 0.03 and increased to 4.87, 5.67
and 4.07 t ha respectively at the final harvest. Except for
the difference between Legon Composite 4 and the others which
was statistically significant (P<0.05), none of the varietal
differences in grain yield was statistically significant (P<
0.05).
Crop residue yield significantly decreased (P< 0.01) with
increasing growth period. The magnitude of the decreases was
21.2%, 11.8% and 14.7% for Ex-Volta, Pol. -16 and Legon
Composite 4 respectively. Significant differences (P< 0.01)
were also observed among varieties. Legon Composite 4 gave the
highest yield of crop residue. This was followed by Pol. -16.
At the second and third harvests when the maize fairly matured,
the ratio of crop residue to grain was 1.3 and 1.1, 1.6 and
1.1, 1.8 and 1.7 to 1 for Ex-Volta, Pol. -16 and Composite 4,
respectively.
243
Figure I. Whole crop, grnin ynd crop residue yield of Uircc varielies of maize
fit different growth pcriotls.
12
10
Ex -Volro Po1 - 16
 
Composite 4.
 
//-
 
125 65 95 125 65
Ooys from sowing to horvesI
 
x it Whole crop o o Crop residue o———a Groin
244
Changes in the percentage composition of the various
morphological fractions of the crop residues are shown in
Figure 2. The trend of developmental changes was mixed for the
various botanical fractions. The proportion of leaves
continuously declined in all varieties with advancing growth
period. On the contrary, the other fractions either increased
initially and later declined or declined initially and later
increased.
Proportional yields of the various botanical fractions of
the residues are shown in Figure 3. Except for a few such as
tassel, cobs and husks, the amounts of the various plant
fractions decreased (P>0.05) with advancing growth period.
Slight varietal differences were also observed but these were
not statistically significant (P> 0.05).
Chemical analyses
Chemical composition of the crop residues are shown in Table 1.
Crude protein content declined considerably (P<0.01) with
increasing growth period. On the contrary, only slight and
non-significant (P>0.05) varietal differences were observed.
The cell wall constituents i.e. NDF, ADF, cellulose and
ADL contents significantly increased (P< 0.01) with increasing
growth period. Ex-Volta had the highest amount of cell wall
constituents at the initial harvest but a mixed trend was
observed at the later harvests. These varietal differences in
neutral-detergent fibre, acid-detergent fibre and cellulose
were however, not statistically significant (P>0.05). Ex-Volta
had a significantly higher ADL content (P<0.05) than Composite
4. The differences between the other two were however, not
significant.
In vi tro dry-matter digestibility (IVDMD) of the crop
residues is shown in Table 2. IVDMD decreased significantly
(P< 0.01) with increasing growth period. Ex-Volta had similar
IVDMD as Composite 4 and these were about 1-4% higher than that
of Pol. -16 at the second or third harvest. These differences
were however, not statistically significant (P> 0.05).
245
Fiptiro ?.. Percent «ko of lx>t»minil fractions of three vnriotios of mnizo at
different frrnwlh periods.
Ex- Voire Pol - 16
35r
30
25
Id
y-
2
UJ
g IS
UJ
a
 
 
OlVA
 
65 95 125
L//-J-
Composlte 4.
 
65 95 125 65 95 12
Days from sowing to harvest
■* Leaves
-• Leaf sheath
-o Stems
-■ Cob
■a Husk
■* Tassel
246
•i- CX3t m .. 25c p_ «+-2 gU t 0)■M Ot •o§ o
10
U
•r"
9
•r"
0> (A O
H- s ro 4J > I 3O S 3 •s 5 ■P
 
D
(,-0q|)suouoojj|ooi iog
Csl
Table 1. Chemical composition of three varieties of maize crop
residues at different harvests (in % dry-matter basis),
Days from Varieties
Chemical sowing to Ex-Volta Pol. -16 Legon
constituent harvest Composite 4
Crude 65 5.66
protein 95 2.75
125 2.68
Neutral- 65 63.78
detergent 95 79.92
fibre 125 49.58
Acid- 65 33.73
detergent 95 45.63
fibre 125 49.58
Cellulose 65 27.28
95 36.63
125 38.48
Acid- 65 6.45
detergent 95 9.00
lignin 125 11.10
Table 2. J_n vitro dry-matter digestibility of three varieties
of maize crop residues at different harvests (in %
dry-matter basis).
Days from sowing Varieties
to harvest Ex-Volta Pol. -16 Composite 4
. 65
95
125
7.00 7.61
3.47 3.09
2.74 2.60
59.07 59.00
79.32 77.26
47.12 49.49
31.82 31.62
45.61 42.85
47.12 49.49
25.86 26.60
36.58 34.64
37.65 40.02
5.96 5.02
9.03 8.21
9.47 9.41
80.1 80.0 80.2
67.9 63.6 67.0
64.5 63.5 65.6
248
Harvest index of grains (HI) and potential utility index
(UI) of the whole crop are shown in Table 3. Harvest indices
significantly increased (P<0.01) with increasing growth period
particularly between the first and harvest. There were no
significant differences between the harvest indices of Ex-Volta
and Pol. -16 but these two were significantly higher (P<0.05)
than those of Composite 4.
Table 3. Harvest index of grain (HI(G>) and potential utility
index (UI) of whole crop of three varieties of maize.
Days from Harvest index (%)
growing to Potential utility index (X)
harvest Ex-Volta Pol. -16 Composite 4 Ex-Volta Pol. -16 Composite 4
65 8.2 13.1 0.4 81.7 82.6 80.3
95 43.3 38.4 35.7 81.8 77.6 78.8
125 48.7 48.3 37.2 81.7 81.1 78.4
No significant differences (P> 0.05) were observed in the
potential utility index of the maize crop residue between
varieties and advancing maturity. The potential utility
however, remained fairly constant and far higher than the
harvest indices.
DISCUSSION
The increase in dry-matter yields with increasing growth period
is consistent with other published results (Raymond, 1969; Lutz
et al, 1971). The particularly low grain yield of Composite 4
at the first harvest could be attributed to the fact that it
was harvested too early relative to its maturity stage (125
days). Ex-Volta had relatively low grain yield considering
that its postulated maturity period was 65 days post-planting.
The results obtained suggested that the best time of harvesting
this variety of maize might be at least 95 days and not 65 days
post-planting.
249
- 1
The final grain yields of 4.87, 5.87 and 4.07 t ha for
Ex-Volta, Pol. -16 and Legon Composite 4 varieties,
respectively, are higher than the range of reported grain
yields of between 0.20 and 2.7 t ha"1 (FAO, 1983, 1986). They
are however, still lower than the potential maximum yield of
6.25 t ha indicated by Dadson (1975). These differences
could be due to a number of factors including genotype,
environment, cultural and economic constraints which may
determine the adoption of a particular cropping system and also
for minimising the influence of the limiting factors (Loomis
and Gerakis, 1975).
With advancing growth there was a decrease in the yield of
crop residue. While this may partly have been due to old
leaves falling off and some losses of plant tops (Westselaar
and Farquhaar, 1980), it may also partly be due to a change in
the physiological state of the plant resulting in a shift in
the source-sink relations in the distribution of photosynthates
(Wareing and Patrick, 1975).
The observation that no significant differences were found
among varieties means that the grain yields were the same and
therefore, at least within a similar ecological zone, any of
the varieties may be used. This observation was however,
contrary to those of Giesbrecht (1969) and Lutz et al (1971)
who noted that late varieties of maize do better than early
varieties when water and nutrients are not limiting.
The changes in the botanical fractions of the crop residue
were similar to that observed with Green Panic and Rhodes grass
(Fleischer, 1986) which are also in the grass family. The
slight varietal differences observed were however, due to the
different time lag in the occurrence of physiological changes
in the different varieties.
Changes in the crude protein content followed trends
similar to published results (Gonske and Keeney, 1969;
Fleischer, 1986, 1987). These were mainly due to the fact that
with advancing maturity plant fractions with structural roles
increase while at the same time soluble components of the
250
protein are transferred to more actively growing points.
Unfortunately, the crude protein contents of the crop residues
at both the 95th and 125th day harvests were lower than the
threshold value of 8.0% indicated by Milford and Minson (1966).
Consequently, it can be expected that intake and utilization of
the crop residues would be low unless supplemented with a
nitrogen-rich source.
Changes in the cell wall constituents also followed a
trend similar to other published results (Fleischer, 1986,
1987). The low values of cell wall constituents at day 65 was
because the plants had just moved from the vegetative to the
reproductive phase. Also beyond that period the bulk of the
crop residues was made up of stems, leaf sheaths, cobs and
husks all of which either offer structural support and/or
protection either to the plant or the grain (Esau, 1965).
Thus, they contain mainly structural carbohydrates which give
them strength to fulfil their roles.
IVDMD declined with advancing growth period. This is
consistent with many published reports (Raymond, 1969) and it
is because with increasing maturity the crop residue is largely
composed of plant fractions with structural roles and therefore
lower digestibility (Hacker and Minson, 1981; Fleischer, 1987).
Even though Ex-Volta was about 1.6% units higher in ADL at
the third harvest compared to either Pol. -16 or Composite 4 it
had slightly more soluble cell wall constituent than the
others. A similar observation has been made by others (McLeod
and Minson, 1974; Fleischer, 1987). The non-significant
difference in digestibility among varieties is contrary to the
observations made by Reed et al, (1986) who, working with
twenty-four varieties of sorghum, observed that the high grain-
yielding varieties can also give a reasonable amount of crop
residues with high nutritive value. In the present experiment,
even though Pol. -16 gave the highest grain yield, Composite 4
gave the highest crop residue yield with the highest
digest ibi lity.
251
CONCLUSION
The present work has shown that grain yield of the three
varieties of maize increased with increasing growth period.
Consequently, harvest index also increased with advancing
growth period. On the contrary, significant decline with
advancing growth period as well as varietal differences were
observed in the crop residue yield. Nevertheless, the ratio of
crop residue to grain was 1.1 - 1.8:1.
Except for a few morphological fractions which differed in
their contribution to the total crop residues, small but non
significant varietal differences were observed.
Crude protein content decreased with advancing growth
period but the varietal differences were not significant.
Nevertheless, the crude protein contents were below the
critical levels necessary to influence intake. Again, all the
cell wall constituents increased with advancing growth period.
However, except for the ADL content of Ex-Volta which was
significantly higher (P< 0.05) than that of Composite 4, no
significant varietal differences were observed.
In vitro dry-matter digestibility declined with advancing
growth period but there were no significant varietal
di f f erences.
Potential utility indices were the same for the three
varieties of maize and did not vary with advancing growth
period. The values were also higher than those of the harvest
indices suggesting that farmers could increase their income if
the crop residues was also used as animal feed.
ACKNOWLEDGEMENT
The authors are grateful to Mr. Abubakari Yakubu for helping
with the chemical analyses and J_n vi tro dry-matter
determination. They are also grateful to the University of
Ghana Research and Conferences Committee for making funds
available for the work.
252
REFERENCES
Arkel, Van H. 1978. The forage and grain yield of sorghum and
maize as affected by soil moisture conservation,
lodging and harvesting losses. Neth. J. Agric. Sci.
26: 181-190.
Brammer, H. 1960. A brief account of agricultural conditions
and factors affecting agricultural development on the
South-Eastern Coastal Plains-Cyclost Report. Ghana
Ministry of Food and Agriculture, Kumasi.
Capper, B.S.; Thompson, E.; Mekui, M. and Anderson, W. 1984.
Cereal straw evaluation. ICARDA Ann. Rep. pp. 295-303.
Dadson, R.B. 1975. Crop production: The desire to achieve
national self-sufficiency. Universitat 4: 162-174.
Esau, K. 1965. Plant anatomy. John Wiley and Sons,
London, N.Y. 767 pp.
Fleischer, J.E. 1986. Harnessing Ghana's renewal energy
resources for increased protein production. In:
Proc. Ghana National Conference on Population and
National Reconstruction, Legon, 7-10 April 1986.
Fleischer, J.E. 1987. A study of the growth and nutritive
value of Green panicum ( Pan i cum maximum var trichoglume
cv Petrie) and Rhodes grass (Chl or is gayana Kunth).
OAU/STRC Bull. Anim. Hlth. and Prod. 35(3): 229-237.
Food and Agriculture Organization. 1983. Integrating crops and
livestock in West Africa. FAO Animal Production Paper
No. 41, FAO, Rome. 112 pp.
Food and Agriculture Organization. 1986. Production Year Book
Vol. 40. FAO, Rome.
Giesbrecht, J. 1969. Effect of population and row spacing on
the performance of four corn (Zea mays L) hybrids.
Agron. J. 61: 439-441.
Gonske, R.G. and Keeney, D.R. 1969. Effect of fertilization
nitrogen variety and maturity on dry-matter yield of corn
grown for silage. Agron. J. 61: 72-75.
Goering, H.K. and Van Soest, P.J. 1970. Forage fibre analysis
(apparatus, reagents, procedures and some applications).
Agriculture Handbook No. 379. US Dept. of Agriculture,
Washington, D.C. 20 pp.
253
Hacker, J.B. and Minson, D.J. 1981. The digestibility of plant
parts. CAB Herb. Abstr. 51 (9): 459-482.
Jenik, Jan and NaIl, J.B. 1976. Plant communities of the Accra
plains, Ghana. Folia Geobot. Phytotax., Praha 11: 163-
212.
Loomis, R.S. and Gerakis, P. A. 1975. Productivity in
agricultural ecosystems. In: J. P. Cooper (ed.),
Photosynthesis and productivity in different
environments. IBP-3, Camb. Univ. Press, Cambridge, pp.
145-172.
Lutz, J. A.; Camper, H.M. and Jones, G.D. 1971. Row spacing and
population effects on corn yields. Agron. J. 63: 12-14.
McLeod, M.N. and Minson, D.J. 1974. Differences in
carbohydrate fractions between Lol ium perenne and two
tropical grasses of similar dry-matter digestibility.
J. Agric. Sci. (Camb.) 82: 449-454.
Menken, U. ter and El-Harith, E.A. 1985. Feeding farm animals
on unused resources in the tropics and sub-tropics. Anim.
Res. and Dev. 22: 116-127.
Minson, D.J. and McLeod, M.N. 1972. The in vitro technique:
Its modifications for estimating digestibility of large
numbers of tropical pasture samples. C.S.I.R.O., Div.
of Trop. Past. Tech. Pap. No. 8. CSIRO, Melbourne,
Australia. 15 pp.
Perry, L.J. 1974. Crop residues grazed by cattle. Farm Ranch
and Home Quarterly 21(3):21-22. Inst. Agric. and
Resources, Univ. Nebraska, Lincoln.
Powell, M. 1985. Contribution of fractionated crop residues
grazed by cattle. Farm Ranch and Home Quarterly
21 (3) :21 -22. Institute of Agriculture and National
Resources, University of Nebraska, Lincoln.
Qureshi, A.W. 1986. Recent trends in livestock development in
Africa and the Middle East. In: Nuclear and related
techniques for animals in harsh environment. IAEA
Proceedings ( IAEA-SR-1 15/1 ) . pp. 17-37.
Raymond, W.F. 1969. Nutritive value of forage crops. Adv. in
Agron. 21: 1-108.
254
Reed, J.D.; TedIa, A. and Jutzi, S. 1986. Large differences
in digestibility of crop residues from sorghum
varieties. ILCA Newsletter 5(1): 5-6. ILCA, Addis
Ababa, Ethiopia.
Wareing, P. and Patrick, J. 1975. Source-sink relationship and
partition of assimilates in the plant. In: J. P. Cooper
(ed), Photosynthesis and productivity in different
environments. IBP-3, Camb. Univ. Press, Cambridge. pp.
481-499.
Weber, D.W.; Vetter, R.L. and Gray, N. 1970. Grazing corn
harvest refuse by beef cows. J. Anim. Sci. 31: 1030
Abst. No. 80.
Westselaar, R. and Farquhaar, A.D. 1980. Nitrogen losses from
tops of plants. Adv. in Agron. 33: 263-302.
255
STUDIES ON THE UTILIZATION OF BREWERS DRY GRAINS
AND WHEAT OFFALS BY CALVES
F.I. Ogundola
Institute of Agricultural Research and Training
P.M.B. 5029, Moor Plantation, Ibadan, Nigeria
ABSTRACT
Digestibility, metabolism and rumen studies were conducted to
study the growth performance of 24 calves fed concentrates
consisting of 20, 40 and 60% levels of both brewers' dry grains
(BOG) and wheat offals (WO) to replace maize in a 16-week trial
period.
There were no trends established between dry matter, total
digestible nutrient and energy intakes and levels of BDG and WO
except the digestible crude protein intake which increased 8.6-
9.5 g/W kg ' with increasing levels of BDG & WO in the ration.
The growth rates of 0.26, 0.27, 0.24 and 0.31 kg/day of
calves on diets A, B, C and D respectively were positively but
not significantly (P>0.05) correlated (r = 0.99).
The N intake (av. 49.7 g/day) and N retention (av. 52.5%)
were high and increased as the level of BDG and WO increased in
the ration.
The rumen pH ranged between 6.4 and 6.8 and was not
different among the diets. The NH,-N levels were high in all
the diets (av. 14.0 mg/100 ml) showing that N was not limiting
and enough to support the growth of the calves. The total VFA
showed no particular trend but moderate accumulation and
averaged 9.8 m-equi v/l i tre. However, the acetic acid level (av.
73%) was high enough to furnish energy for the N utilisation.
For the individual acids, no definite pattern was established
in relation to the supplemental levels of BDG and WO.
The growth made by the calves indicated that both N and
energy were not limiting even at 60% substitution level.
256
INTRODUCTION
In view of the rapidly growing population and declining grain
production in Nigeria there is an increased need to utilise
agro- industrial by-products and crop wastes to feed livestock.
Furthermore, it is becoming increasingly difficult to supply
cereal grains to the livestock industry.
Recently a large number of breweries and flour mills have
been established in almost all the states of Nigeria from which
large quantities of brewers' dried grains (BDG) and wheat
offals (WO) become available as sources of energy and protein
for livestock feeding. Adebowale (1985) reported that about
100,000 and 320,000 tons of wet brewers' grains and wheat
offals were available from the brewery and flour milling
industries. Some of the breweries have facilities for drying
the grains while others have none. The dried grains are made
available free to livestock farmers to avoid environmental
pollution while the cost of a tonne of wheat offals is about
25% of the cost of a tonne of maize.
Adebowale and Ademosun (1981) and Ogundola (1987) analysed
some samples of the BDG and WO and found that generally they
contain about 20% and 15% crude protein as well as 21 KJ/g and
17 KJ/g gross energy respectively. These values are higher than
those of maize and guinea corn which are commonly used as
energy sources in rations for livestock.
This paper reports on the metabolism and rumen studies
using different levels of BDG and WO as maize replacement in
rations for young growing calves.
MATERIALS AND METHODS
Twenty-four white Fulani (Zebu) calves aged between 14 and 16
months were selected from the flock of the Institute's Research
Farm for the experiment. The average weight of each animal was
81 kg.
257
Before the digestibility experiment, the animals were kept
on concrete floor pens and zero-fed 3 kg of grass (Cynodon
nlemf uensis) and a daily allowance of 1.5 kg of the test diets
(concentrates) A, B, C and D in groups of six, for 16 weeks to
evaluate their feed intakes and growth rates. After the trial,
12 calves were selected for the metabolism and rumen studies.
All the calves were housed in specially constructed metabolic
cages to facilitate separate collection of faeces and urine.
The animals were fed at the same rate with three on each test
diet. A preliminary period of 14 days was allowed before faeces
and urine collection which lasted 7 days was started. Fresh
clean water was available ad I ib in plastic buckets placed at
the corner of each metabolic cage.
Faecal collection
Faecal collection was done by means of collection bags fitted
with harness and the total weight of faeces voided weighed and
recorded. A sample of the faeces voided daily was taken, dried
in the oven at 80 C for 24 hours. The daily dried faeces for
each animal over the 7- day collection period were bulked. The
samples were then milled and stored in airtight bottles until
required for analysis. Urine was collected over 5 ml of 10%
mercuric chloride solution in a plastic container. The daily
volume was measured every morning and 10% aliquot taken for
nitrogen and energy determinations. Samples not ready for
immediate analysis were kept in a deep freezer at -5 C. The
methods for the collection of feed refusals and faeces were as
described by Oyenuga (1961).
Fresh faeces, herbage fed and residues meant for proximate
analysis were dried at 80 C in a forced-draught electric oven
for 3 days and later milled in a Chri sty-Norris hammer mill
fitted with 2 mm sieve. The milled samples were later analysed
for their proximate analysis.
258
Sampling of the rumen liquor
Rumen samples were collected during the last 3 days of the
collection period by putting the collection tube through the
mouth into the rumen using the method of Alexander (1964) as
modified by Mba and Olatunji (1971). The sampling lasted 5
minutes during which about 200 ml of rumen liquor was obtained.
The samples were taken one hour before and one hour after
feeding. They were then stored in a deep freezer at -5 C until
required for analysis.
Analytical procedure
The AOAC (1970) procedures were used for the proximate
constituents in feed and faeces, nitrogen in urine and volatile
fatty acids (VFAS). Individual fatty acid was determined on the
Beckman's Gas- liquid Chromatography model 65. The pH was
measured on pH Meter E520 using glass reference electrodes. The
gross energy of faeces and feed was determined in a Gallenkamp
ballistic bomb calorimeter while gross energy in urine was
determined by drying a known volume soaked in a pre-weighed
ashless filter paper over P?0c in a desiccator reweighed after
drying followed by bombing.
All data were subjected to analysis of variance (Steel and
Torrie, 1960). Regression analysis was thereafter used to
measure the trend of association (r-value) between BDG and
wheat offals level in diet (X) and nutrient (Y).
RESULTS
The brewers' dried grain and wheat offals used in the
metabolism and rumen studies had crude protein of 18.3% and
12.1%, 17.4 and 14.8% crude fibre; 4.5 and 4.2% ether extract;
6.4 and 7.1% ash; and 19.4 and 17.9 KJ/g respectively (Table
1).
Generally values for voluntary dry matter (DM),
digestible crude protein (DCP), total digestible nutrient (TDN)
259
and energy intakes are high in all the four diets (Table 2).
However, there are not significant negative correlation between
DM intake (r -0.65), and energy intake (r = -0.088) but
significant negative correlation existed between TDN (r = 0.94)
and level of supplementation of BDG and WO in the diets. But
there is a positive correlation between DCP intake and level of
supplementation (r = 0.99). There was no established trend in
the intake of nutrients between the four diets. The weight
gained by the calves were moderately high (0.24-0.31 kg/day) on
all the diets while a non-significant correlation (r = 0.03)
was obtained between these gains and level of supplementation
of BDG and WO.
Table 1. Composition of experimental diets.
Ingredients (%)* A B C D
Maize 77.5 57.5 37..5 17.5
Groundnut cake 15.0 15.0 15..0 15.0
Palm kernel meal 5.0 5.0 5,.0 5.0
Dry brewers' grain 0.0 10.0 20..0 30.0
Wheat offals 0.0 10.0 20..0 30.0
Chemical composition (%) on DM basis
Crude protein 13.96 15.03 16.13 17.21
Crude fibre 3.20 5.71 8.21 10.71
Ash 2.40 3.23 4.06 4.89
Ni trogen-f ree
extratives 71.45 64.80 58.20 51.6
Gross energy (MJ/Kg) 15.49 15.97 16.53 17.09
* All diets contain 1% bone meal, 0.5% salt, 1.0%
mineral/vi tam in mixture. Cynodon nlemf uensis had a
chemical composition of 6.4% crude protein, 27%
crude fibre, and 17.9 MJ/Kg gross energy.
Composition of min/vit mixture as quoted by Ogundola
(1984).
260
Table 2. Intake and growth rate of calves.
DM intake DCP TDN Energy Growth Cost/kg
Diet 0.75 0.75 0.75 intake rate ration
g/ kg 9/ kg g/ kg ME/Kg DM kg/day (N)
A 92.8 8.6 81.3 67.8 0.26 1.31
B 90.2 8.9 74.0 60.1 0.27 1.22
C 93.4 9.3 72.8 67.8 0.24 1.14
D 86.5 9.5 69.5 64.4 0.31 1.05
Mean+SE 91.7+2.7 9.1+0.4 74.4+4.3 65.0+3.2 0.27+0.03 1.18+0.1
r-value 0.84ns 0.99 -0.95 -0.08ns 0.53nS -0.99
ns = not significant.
* = significant at 5%.
*** = significant at 0.1%.
H = unit of local currency.
There was no definite trend in the digestibilities of the
various components as the level of BDG and WO increased in the
diet (Table 3). However, non-significant negative correlations
were obtained between dry-matter, crude protein and crude fibre
digestibilities and level of supplementation. Energy
digestibility however correlated positively (r = 0.30) but not
significantly with levels of BDG and WO in the diet.
261
Table 3. Mean coefficient of apparent digestibilities.
(%) of diets
Diets DM CP CF Energy
A 68.8 73.4 70.2 76.8
B 66.3 70.7 68.4 73.2
C 69.7 72.0 65.7 74.6
D 61.9 70.9 69.6 78.0
Mean+SE 66.7+3.0 71.8+1.1 68.5+1.7 75.7+1.9
-0.29nS 0.30ns
ns = not significant.
At the end of the trial, all the animals were in positive
nitrogen balance (Table 4). Intake of N increased with the
level of supplementation (43.6-54. 7g/day) . Also faecal-N and
urinary-N excretion increased with the levels of BDG and WO
levels in the diet as shown by the (r) values. However, though
N retention positively correlated (r =0.85) with level of BDG
and WO in the diet, it was not significant (P>0.05).
Table 4. Nitrogen utilisation by calves.
Diets A B C D Mean+SE r value
Nitrogen intake (g/day) 43.6 47.9 52.4 54.7 49.7+4.3 0.99
Faecal-N(g/day) 9.8 10.4 10.9 11.2 10.6+0.53 0.99*
11.4 13.0 13.3
22.4 24.5 28.2
51.4 51.1 53.8
Urinary-N (g/day) 14.1 13.0+0.98 0.96
N-retention (g/day) 29.4 26.1+2.8 0.98*
N-retention(% of intake) 51.4 51.1 53.8 53.7 52.5+1.3 0.86ns
ns = not significant.
* = significant at 5%.
262
There were non-significant (P>0.05) positive
correlations between the various contents and levels of BDG and
WO in the diet as shown by their r values (Table 5). Rumen pH
varied between 6.4 and 6.8, ruminal-NH3-N 11.7-15.4 mg/100 ml.
Total VFA 9.6-10.1 m-equi v/l i tre, acetic acid 69-76%, propionic
Acid 14.8-20% and butyric acid 5.2-12.1% in all the diets.
However, only ruminal NH,-N content exhibited a gradual
increase with the level of supplement in the diet.
Table 5. Mean rumen pH, NH^-N, total and individual VFAs of the
calves.
Diets Rumen Ruminal Total Acetic Propionic Butyric
pH NH3-N VFA acid (%) acid (%) acid (%)
A 6.8 11.7 9.9 69.4 19.2 11.4
B 6.5 14.8 9.7 74.8 20.0 5.2
C 6.4 14.2 10.1 76.0 17.2 6.8
D 6.5 15.4 9.6 73.1 14.8 12.1
Mean+SE 6.6 14.0 9.8 73.0 17.8 8.9
■♦ 0.15 + 1.4 +0.19 + 2.5 +2.0 +2.9
r value -0.75ns 0.83ns -0.29ns 0.55ns -0.89ns 0.14nS
ns = not significant.
DISCUSSION
Consumption of feed by the calves was generally high in the
four experimental diets A,B,C and D and even compared with
NRCC1966) recommendation for calves of similar weight. This
showed that the feeds were well accepted by the calves.
However, DM consumption of calves on diet D with 30% each of
BDG and WO recorded the lowest value. This appeared to agree
with Adebowale's (1985) report that supplementation of BDG
above 25% tended to depress DM consumption, and that the BDG
should be in wet form because calves generally consumed the wet
BDG than the dry one at this level of supplementation.
263
The high digestibility coefficient obtained for the DM,
CP, CF and energy reflected the high CP in the diet which
ranged between 14 and 17% and is known to affect particularly
the digestibilities of DM and CF. The daily weight gains of the
calves (0.24-0.31 kg) on the different diets were high compared
to earlier report by this author. The observations of Fehr et
al (1976) and Naude and Hofmeyer (1981) that high feed intake
and high growth rate positively affect feed utilisation
efficiency is adequately supported by the present findings. The
growth made by calves on rations B, C and D indicated that both
CP and energy were adequate in the diets and the highest rate
of (0.31 kg/day) was recorded on ration D.
In all the diets, there was a positive correlation between
N intake and N retention. The latter seemed to increase with
the level of BDG and WO substitution. All the animals were
therefore in positive N balance, indicating that the N contents
of BDG and WO were well utilised by the calves.
The results of the rumen studies showed a generally high
ruminal NHj-N (11.7-15.4 mg/100ml) & fairly low acetic acid
levels of 69-76%. These high NH,-N levels would support high
microbial growth which in turn will lead to efficient
utilisation of N in the diet. These findings agree with the
explanation of Mba and Olatunji (1972) that acetic acid
depression enhance N retention and reduces absorption of NH,-N.
The relatively low acetic acid level and the high growth rate
recorded in this trial agreed with Mba et al (1971)
observation.
CONCLUSION
The experiment has shown that both BDG and WO which are
abundant in Nigeria could be incorporated in the diet of
growing calves up to 60% of the ration without adverse effect
on nutrient digestibility and utilisation. However, inclusion
of BDG above 30% may have to be in wet form. The greatest hope
for the utilisation of these by-products lies in the fact that
they need no further processing before they could be used as
feed. However, most of the flour mills and breweries are
264
located in the coastline of the country, and government should
now force new flour mills and breweries to be established in
the hinterland to reduce transportation costs to large
livestock population areas. In addition, breweries with no
drying facilities should be compelled to install drying plants
to make more BDG available for livestock. From experience, the
more frequently one calls at the source of any agro- industrial
by-product centre, the more likely one is asked to pay some
money for whatever quantity one collects even though the owners
may have no particular use for such products. Government should
enforce price control to keep the price of BDG and WO very low
to encourage their use as a livestock feed.
REFERENCES
Adebowale, E.A. and Ademosun, A. A. 1981. Studies on the
utilisation of brewers dried grains by sheep and
goats. 1. Growth studies. Bull. Anim. Health Prod.
Afr. 29: 365.
Adebowale, E.A. 1985. Non-conventional feed resources in
Nigeria. NIFOJ 1, 2 and 3. p. 181.
Alexander, R.H. 1969. The establishment of a laboratory
procedure for the j_n vi tro determination of
digestibility. Research Bull. No. 42. West of Scotland
Agric. Coll.
AOAC (Association of Official Analytical Chemists). 1970.
Official methods of analysis. 12th ed. Association of
Official Analytical Chemists, Washington, D.C.
Fehr, P.M. 1976. Effect of feeding methods and age at
slaughter on growth performance and carcass
characteristics of entire male goats. Livestock Prod.
Sci. 3. 183.
FAO (Food and Agriculture Organization). 1981. FAO Production
Year book. Vol. 35. FAO, Rome.
Mba, A.U. and Olatunji, 0. 1971. Studies on VFA production in
Zebu cattle and African dwarf goat. W.A.J. Biol. Appl.
Chem. 14: 13.
Naude, R.T. and Hofmeyer, H.S. 1981. Meat production. In: C.
Gall (ed.), Goat production. Academy Press, London.
265
NRC (National Research Council). 1966. Nutrient requirements
of domestic animals. No. 3. National Research Council,
Washington, D.C.
Ogundola, F.I. 1977. Energy and protein utilisation of milk-
fed calves. Ph.D. thesis, University of Ibadan, Nigeria.
Ogundola, F.I. 1984. Ruminal ammonia and plasma urea
relationship in calves. E. Afr agr For J 46(2): 23.
Steel, R.G.D. and Torrie, J.H. 1960. Principles and procedures
of statistics. McGraw-Hill Book Co., New York.
266
THE EFFECT OF MAIZE BRAN ON VOLUNTARY INTAKE
AND DIGESTIBILITY OF PIGEON PEA
(CAJANUS CAJAN) PODS BY GOATS
J. A. Ayoade
Department of Animal Science
University of Malawi
P.O. Box 219
Lilongwe, Malawi
ABSTRACT
Three male Malawi local goats (about 19 kg) were used in a 3 x
3 Latin Square design experiment to investigate the effect of
maize bran supplementation on the voluntary intake and
digestibility of pigeon pea pods by goats. The treatments
were: (a) ad libitum pods; (b) treatment a (i.e. ad I ibitum
pods) plus 100 g maize bran/goat/day; and (c) treatment a plus
200 g maize bran/goat/day. The voluntary dry-matter intake and
digestibility of pigeon pea pods by goats were improved with
maize bran supplementation, but not statistically significant
(P>0.05). It is concluded that pigeon pea pods supplemented
with maize bran could be used as a dry-season ration for goats
in the villages when good quality forages are scarce.
INTRODUCTION
A study with sheep (Bell, 1978) suggested that pigeon pea pods
as a sole diet are of low nutritive value and that the
inclusion of small amounts of high quality pangola grass
(Digi taria decumbens) considerably improved the nutritive
value. Utilization of maize bran to supplement pigeon pea pods
would be particularly appropriate for small-scale as well as
large farms in Malawi. Large amounts of maize bran are
produced in the villages resulting from the use of maize as
staple crop. The objective of this study was to investigate
the effect of maize bran supplementation on voluntary intake
and digestibility of pigeon pea pods by goats.
267
MATERIALS AND METHODS
Three male Malawi local goats (about 19 kg) were used in a 3 x
3 Latin Square experiment to investigate the effect of maize
bran on voluntary intake and digestibility of dried pigeon pea
pods by goats. The treatments were (a) ad I ibi tum dried pods;
(b) treatment a (i.e. ad I ibi tum pods) plus 100 g maize
bran/goat/day; and (c) treatment a plus 200 g maize
bran/goat/day. At the beginning of the experiment, the animals
were treated for parasites and were confined in individual
metabolism crates throughout the experiment. The experiment
was divided into three 14-day periods consisting of a 9-day
preliminary period followed by a 5-day collection period.
Maize bran was fed at 0800 hours daily and the pigeon pea pods
were given three hours later. No mineral supplements were
given. Clean drinking water was made avai lable* dai ly. Feeds
(offered and refusals) samples were analysed for dry matter,
ash and crude protein while faecal samples were analysed for
dry matter and ash using the AOAC (1970) procedures. Data were
subjected to analysis of variance.
RESULTS AND DISCUSSION
The chemical composition of the pigeon pea pods and maize bran
used in the study (Table 1) is similar to that used by Bell
(1978). The dry-matter, organic matter and crude protein
contents of the maize bran are also within the range reported
for maize bran from some Central Malawi villages (Ayoade,
unpubl i shed) .
Table 1. Proximal chemical composition of pigeon peas and
maize bran (as fed basis)
Dry Crude Gross
matter protein Ash energy
(%) (%) (%) (MJ/kg)
Pigeori pea pods 91,.7 7..0 4..7 14 .8
Maize bran 88..9 9..6 2 .4 1..9
268
The voluntary dry-matter intake (DMI) and digestibility of
pigeon pea pods by goats are presented in Table 2.
Table 2. Voluntary intake and digestibility of pigeon peas
(Ca janus ca ian) pods as affected by maize bran
supplementation.
Level of maize bran supplementation
(g/goat/day)
100 200 SEx
385.7 356.8 329.8 24.0
2460.3 2179.5 2054.8 147.8
48.8 43.7 40.8 3.0
385.7 445.4 491.7 30.0
2460.3 2770.5 3075.4 82.8
48.8 55.3 60.9 2.3
Daily dry-matter intake
(pods) g
g/100 kg body weight
9/ kg W
Daily total dry-matter
intake g
g/100 kg body weight
g/ kg W
Dai ly free water
intake (litres) 0.53 0.66 0.50 0.05
Digestibility (%):
Dry-matter
Organic matter
w
Significant at P>0.05.
The voluntary DMI of pigeon pea pods by goats was reduced
while the total DMI by the goats was increased with maize bran
supplementation (Table 2). However, these differences were not
statistically significant. All animals lost weight while on
pigeon pea pods alone and maintained their body weight or
gained weight slightly while on the supplemented treatments.
This indicates that pigeon pea pods alone did not meet the
maintenance requirements of the goats. Similar observations
were obtained by Bell (1978) when pigeon pea pods alone were
46.0 51.7 55.0 1.1
49.7 54.9 55.9 2.6
269
fed to sheep. The maintenance of body weight and slight body
weight gain by goats while on the supplemented treatment
indicate the importance of supplementation of pigeon pea pods
if maintenance of growth is to be realised in the animals
(Bell, 1978).
There were no significant differences among the treatments
in the mean daily free water intake of the goats (Table 2).
However, there was tendency for a greater free water intake for
animals fed pigeon pea pods plus maize bran compared to those
fed pigeon pea pods alone.
Supplementation with maize bran improved digestibilities
of dry matter and organic matter of pigeon pea pods by goats
(P>0.05). This agrees with the findings o.f Bell (1978), Ayoade
and Tambala (1984), Devendra (1982) and Mosi and Butterworth
(1985) who reported improved digestibility of low quality
roughages through concentrate/high quality forage
supplemental ion.
The results of the study indicate improved utilization of
pigeon pea pods by goats with maize bran supplementation. When
compared with the results of Bell (1978), the goats utilized
pigeon pea pods alone better than the sheep. It is concluded
that pigeon pea pods supplemented with maize bran could be used
as a dry season ration for goats by the small-scale farmers
when good quality forages are scarce.
ACKNOWLEDGEMENTS
This study was funded by University of Malawi Research and
Publications. The author thanks Professor O.T. Edje for
supplying the dried pigeon pea pods and Mr. M.M. Kayange for
analysing the samples.
REFERENCES
AOAC (Association of Official Analytical Chemists). 1970.
Official methods of analyses. 11th edition. AOAC,
Washington, D.C.
270
Ayoade, J. A. and Tambala, P.A.J. 1984. The effect of
concentrate supplementation on voluntary intake and
digestibility of chopped groundnut haulms by goats.
African Research Network for Agricultural By-products
Newsletter 3(4):5. ILCA, Addis Ababa, Ethiopia.
Bell, G.D. 1978. The nutritive value of pigeon pea (Cajanus
cajan) hulls and cassava (Manihot esculenta) leaf for
sheep. University of Queensland, Agriculture
Department, Research Project Report, St. Lucia,
Queensland, Australia.
Devendra, C. 1982. Perspectives in the utilization of
untreated straw by ruminants in Asia. In: P.T. Doyle
(ed), The utilization of fibrous agricultural residues as
animal feed. pp. 7-26.
Mosi, A.K. and Butterworth, M.H. 1985. The voluntary intake
and digestibility of diets containing different
proportions of tef (Eragostis tef) straw and Tri folium
tembense hay when fed to sheep. Tropical Animal
Production 10(1):19-23.
271
THE OPTIMUM LEVEL OF ROUGHAGES IN THE
DIETS OF SHEEP
A.M. Nour, A.R. Abou Akkada, A. A. Nour and Awad Mabrouka
Department of Animal Production, Faculty of Agriculture
University of Alexandria, Alexandria, Egypt
ABSTRACT
Five groups of male lambs each of nine head Rahmany Barki were
used to investigate the effect of different levels of corn
stover (10, 30, 50, 70 and 90%) in pelleted diets on the growth
performance and feed utilisation by lambs.
The results showed that voluntary feed intake, average
daily gain and feed utilisation were significantly decreased by
increasing the level of corn stover in the diet from 10 to 90%.
The digestibilities of DM, OM and CP were decreased by
increasing the level of corn stover in the diet (with the
exception of the diet containing 70% corn stover), however,
crude fibre digestibility increased by increasing the level of
corn stover.
The results recommended a pelleted diet containing 70%
corn stover for growing lambs to achieve a good growth with
lower cost of meat production. The cost of feed per one kg gain
was 1.25, 1.12, 1.08, 0.91 and 5.88 LE for diets containing 10,
30, 50, 70 and 90% corn stover respectively.
INTRODUCTION
There is a shortage of about 5-6 million tons of TDN which are
required to secure better nutritional status of farm animals in
Egypt.
On the other hand, the utilisation of the agro- industrial
by-products (13-14 million tons DM/annum) can easily fulfil the
present shortage in the amount of TDN needed to cover in animal
feed requirements.
272
Corn (Zea mays L.) is grown (about 2 million feedans) in
Egypt mainly for grain and it is the general farm practice to
leave the ears on the stovers in the field until the grains are
almost completely dry. The dry corn stover (about 4.3 million
tons/annum), therefore is not suitable for animal feeding and
is only used as fuel. It has been shown that corn stover can be
successfully ensiled without any significant change in its
nutritive value (Soli man et al, 1975 and 1977).
Shehata and Nour (1985) found that pelleting of rice straw
with concentrates, molasses, urea and minerals can provide a
suitable complete diet for use on large farms in Egypt. The
main objective of this work was to study the effect of
different levels of corn stover in pelleted diets on the
digestibility of nutrients. Feed intake, growth performance and
cost of meat production from sheep.
MATERIALS AND METHODS
Corn stover constituted 10, 30, 50, 70 and 90% of complete
pelleted diets, the compositions of which are shown in Table 1.
Forty five Barki lambs of about 26 kg each were allotted
randomly to five groups each of nine head. Each group was fed
on one of the five experimental diets ad lib. plus one kg fresh
berseem per head daily/(213 g DM) at 9 a.m.; water was offered.
Feed refusals were collected daily and weighed. The experiment
lasted for 75 days, and the animals were weighted every two
weeks before being fed or watered.
273
Table 1. Composition % of pelleted diets containing corn stover.
Diet
1 2 3 4 5
Per cent
Corn stover 10 30 50 70 90
Urea - 0.25 0.5 1 1.5
Soyabean by-products 20 20 20 20 -
Wheat bran 30 20 10 - -
Milling by-products 30 20 10 - -
Molasses 8 8 8 8 8
Calcium carbonate 1. 4 1.4 1.4 1. 4 1.4
Salt 0. 5 0.5 0.5 0. 5 0.5
Mineral mixture 0. 1 0.1 0.1 0. 1 0.1
Digestibility and N- balance trials were conducted during
the last two weeks of the experiment on three animals from each
group chosen randomly. Animals were fitted with nylon bags and
harnesses for complete collection of faeces, and urine was
collected daily in jars containing 5 ml concentrated HCl.
Faeces were collected daily, mixed thoroughly, weighed and 10%
of each day's collection was used for dry-matter determination.
The samples collected over the period (7 days) were combined,
ground, and kept for chemical analysis.
The volume of urine was measured daily & a 10% portion of each
urine collection was kept for determination of urinary nitrogen.
Analysis of diets, faeces and urine were carried out
according to the methods of AOAC (1970).
The cost (LE/ton) of feed ingredients in the experimental
diets is shown in Table 2.
Statistical analyses were conducted according to Snedecor
and Cochran (1967).
274
Table 2. Cost (LE/ton) of feed ingredients in the experimental
diets.
Diet
1 2 3 4 5
Corn stover 3 9 15 21 27
Urea - 0.55 1.1 2.2 3.3
Soybean meal 50 50 50 50 -
Wheat bran 36 24 12 - -
Milling by-products 36 24 12 - -
Molasses 6. 4 6.4 6.4 6.4 6.4
Calcium carbonate 0. 56 0.56 0.56 0.56 0.56
Salt 0. 25 0.25 0.25 0.25 0.25
Mineral mixture 0..50 0.50 0.50 0.25 0.25
Total cost (LE/ton) 132.70 115.26 97.81 80.66 37.76
1 LE=0.44 US$
RESULTS AND DISCUSSION
Chemical analysis of the corn stover and the 5 diets are shown
in Table 3.
Digestibility determinations (Table 4) showed that the
digestibilities of dry-matter (DMD), organic matter (OMD),
crude protein (CPD) and nitrogen-free extract (NFED) were
significant (P<.05); however, crude fiber digestibility (CFD)
was significantly (P<0.01) increased by increasing the level
(%) of corn stover in the diet. The digestibility coefficient
of corn stover alone was CP, 36%; EE, 59%; CF, 67% increased
and NFE, 60% and its nutritive value was: TDN 48.78% and DP,
1.8%, as reported by Badr (1960). Thus corn stover is a low
quality feed, principally because of its high percentage of
lignocel lulose, low percentage of protein and the deficiency of
readily available carbohydrates which limit microbial activity
in the rumen.
275
Table 3. Chemical analyses (%) of corn stover and the tested diets.
Corn
Diet no.
stover 1 2 3 4 5
Dry-matter 85.2 91.13 89.34 90.57 91.02 91.02
Organic matter 91.49 88.88 90.08 90.41 90.09 89.33
Crude protein 5.4 11.33 11.18 11.03 11.59 9.27
Crude fiber 33.2 15.45 17.90 18.05 25.87 28.31
Ether extract 1.45 2.84 1.82 1.42 1.28 1.05
Ash 8.51 11.12 9.92 9.59 9.19 10.67
Nitrogen-free extract 51.7 59.26 59.28 59.91 51.35 50.73
The nutritive value of the tested diets (Table 4) was
decreased by increasing the level of corn stover.
Dry-matter intake and liveweight changes of the lambs
during the 75-day growth period are shown in Table 5. All lambs
gained weight during the feeding experiment. Statistical
analysis showed that the average total and daily gains were
significantly influenced by increasing the level of corn stover
in the diet. The body weight gains from diets containing 70 and
90% corn stover were significantly decreased (P<0.01). However,
the differences between the diets containing 50 and 70% or 30
and 50 or 10 and 30% corn stover attained significance at 5%
level (Table 5). The weight gain was very low with the diet
containing 90% corn stover (Diet 5), providing nutrients
sufficient virtually only for maintenance. The feed utilisation
(feed/gain ratio) was greatly improved by increasing
concentrates in the pelleted feed from 10 to 30%. These
differences were highly significant (P<0.01), but that between
the diets containing 30 and 50% was not significant.
276
Chemical analysis X of be r seem
DM OM CP CF EE NFE
88.04 87.31 17.49 26.92 2.46 40.43
Table 4. Feed intake (g/head/day), digestibility (%) and
nutritive value (%) of different pelleted diets.
Diet
1 2 3 4 5
Feed intake g/head/day
Digestibi litv %
1443
+297
1331
+ 107
1326
+ 76
1257
+ 52
1223
+ 26
Dry-matter 64.01 60.47 54.49 63.07 50.25
+3.12 +3.78 +3.02 +3.86 +5.6
Organic matter 65.22 62.00 55.72 64.65 51.81
+2.98 +3.19 +5.96 +3.58 +2.04
Crude protein 55.66 54.94 53.27 55.51 47.83
+1.42 +2.58 +4.03 +2.41 +11.8
Crude fiber 53.58 49.36 47.68 63.34 57.64
+10.26 +8.22 +4.76 +3.32 +4.43
Ether extract 55.92 59.76 44.79 59.61 54.49
+8.1 +1.86 +6.65 +1.77 +4.34
Nitrogen-free extract 72.03 67.00 64.98 63.34 50.69
+0.62 +1.6 +1.03 +3.32 +4.41
Nutritive value %
DCP 6.81 6.72 6.43 6.98 5.1
+0.17 +0.33 +0.5 +0.27 +0.87
TDN 60.59 60.43 54.22 54.2 48.32
+0.81 +3.98 +2.19 +1.52 +4.29
277
Table 5. Growth performance of the growing lambs fed on
different diets containing corn stover.
Diet no.
1
No. of animals 9 9 9 9 9
Initial weight (kg/head) 26.44 26.83 25.89 26.61 27.11
+6.07 +6.27 +5.13 +5.10 +4.45
Final weight (kg/head) 37.5 36.39 33.56 32.83 27.61
+7.13 +9.02 +8.73 +6.75 +4.06
Feeding period (days) 75 75 75 75 75
Gain (kg) 11.06 9.56 7.70 6.89 0.5
+2.22 +3.87 +4.56 +3.47
Average daily gain 147 127 102 92 6.0
(g/head/day) +30 +50 +60 +46 +13
*
Average feed intake
(g/head/day) 1387 1231 1123 1041 935
Feed gain ratio 9.44 9.69 11.01 11.31 155.83
Cost of one kg gain
from feed (LE/kg) 1.25 1.12 1.08 0.91 5.88
*
Feed intake from the pelleted diets plus 212 gm dry matter
from
berseem in fresh form daily.
It is relevant to note in this context that for the
maintenance of adult ruminant, the characteristics desirable in
the feed are:-
(1) crude protein level which is above 6-7%.
(2) dry-matter digestibility of about 50-55% and DMI of
the order of 1.7% of the body weight.
278
Preston and Leng (1984) showed the following nutritional
factors merit attention in order of priority:-
(1) fermentable energy
(2) fermentable nitrogen
(3) micronutrients (especially S, P and B vitamins)
(4) roughages (for adequate rumen function)
(5) by-pass protein, and
(6) by-pass energy.
To overcome the nutritional constraints of corn stover,
supplementation with concentrates (energy, protein minerals
etc) and green fodder were tried in order to find suitable
combinations that are both acceptable and beneficial to the
growth of lambs.
The foregoing data indicate that increasing the level of
concentrate from 10 to 30% in the diet was sufficient to
provide enough nutrients to increase the weight gain of the
animals from just above maintenance (6 g/head/day) when fed on
Diet 5 to a moderate level of growth (96 g/head/day) when fed
on Diet 4. More increase in the average daily gain was achieved
by increasing the level of concentrates. However, the rates of
increase in weight gain were lower than that obtained by adding
30% concentrates.
El Shinnawy and Abou Raya (1983) reported that pelleting
mixtures including maize stalks seemed to increase the feeding
value of the mixture to an extent greater than would be
calculated from the individual ingredients. Pelleting mixtures
results in a satisfactory intake when directly fed to lambs,
and the increased feed density and more efficient packing
capacity reduces transporting expenses.
Table 2 shows that the diet containing 90% corn stover was
cheap (37.76 LE/ton), and that containing 10% corn stover was
the most expensive (132.7 LE/ton). However, the cost of
production of 1 kg gain from the tested feeds (Table 5) showed
that the most economical mixture was that containing 70% corn
stover (0.91 LE/kg).
279
Thus the present results indicate that the pelleted diet
containing 70% corn stover is a suitable diet for feeding
growing lambs in Egypt.
REFERENCES
AOAC (Association of Official Analytical Chemists). 1970.
Official methods of analysis. AOAC, Washington, D.C.
Badr, M.F. 1960. Corn stover. Its chemical composition and
nutritive value in livestock ration. Alex. J. Agric.
Res. 7(1): 15-24.
Devendra, C. 1985. Forage supplements: Potential value in
feeding systems based on crop residues and agro-
industrial by-products in south east Asia. Proceedings
of the International Workshop held in Khon Kaen,
Thailand, November 29 - December 2, 1984. pp. 221-248.
El-Shinnawy, M.M. and Abou Raya, A.K. 1983. Unconventional
feeds. Min. of Agr. Cen. Admin. for Anim. Prod, Arab
Republic of Egypt.
Preston, T.R. and Leng, R.A. 1984. Supplementation of diets
based on fibrous residues and by-products. In: F.
Sundstol and E. Owen (eds), Straw and other fibrous by
products as feed. Elsevier Press, Amsterdam. pp. 373-
913.
Shehata, M.N. and Nour, A.M. 1986. Rice straw in complete
pelleted diets for sheep. In: T.R. Preston and M.Y.
Nuwanyakapa (eds), Towards optimal feeding of
agricultural byproducts to livestock in Africa.
Proceedings of a workshop held at the University of
Alexandria, Egypt, October 1985. ILCA, Addis
Ababa, Ethiopia. pp. 79-86.
Snedecor, G.W. and Cochran, W.H. 1967. Statistical methods.
6th edition. Iowa State Univ. Press, Ames, Iowa, U.S.A.
<
280
Soliman, S.M.; Abou Akkada, A.R. and Naga, Habib, M.M. 1975.
The use of corn fodder, its silage and corn stover as
an animal feed. III. A composition between the
digestibility and protein biological value of the three
products. Alex. J. Agric. Res. 23(1) :21.
Soliman, S.M.; El-Shazly, K. and Abou Akkada, A.R. 1977. Some
aspects of the use of corn stover silage in animal
feeding. Alex. J. Agric. Res. 25(3): 423-428.
281
RESPONSE OF THE WEST AFRICAN DWARF SHEEP TO DIETS BASED ON
PROCESSED CASSAVA PEELS AND GLIRICIDIA SEPIUM
A. A. Adegbola, O.B. Smith and V.O. Asaolu
Department of Animal Science
Obafemi Awolowo University
Ile-Ife, Nigeria
ABSTRACT
Three experimental diets consisting of 100% G I i r i c i d i a sepium:
80% ensiled cassava peel plus 20% G I i r i c i d i a . and 80% dried
cassava peel plus 20% G I i r i c i d i a were fed to 12 West African
Dwarf (WAD) sheep on an ad I ibitum basis for 12 weeks.
Animals fed on G I i r i c i d i a alone consumed 1044 g DM per day
to produce 106 g weight gain per day over the 12 weeks, while
those fed on the ensiled cassava peels with G I i r i c i d i a consumed
716 g DM per day to achieve a weight gain of 81 g/day. Animals
fed on the dried cassava peel based diet performed poorest
consuming 642 g DM per day and gaining 59 g/day.
The higher dry-matter intake and better growth rate of the
animals fed on the ensiled cassava peel based diet over those
of animals on dried cassava peel-based diet were attributed to
lower prussic acid content as well as the sweet and pleasant
odour of the ensiled cassava peels.
INTRODUCTION
In towns and villages where sheep and goats are kept in the
backyard production system, it is usual to give them whole
cassava chips in the mornings or evenings. These animals obtain
their protein supplements from browsing and scavenging around
the village. One of such browses available to sheep is
G I i r i c i d i a sepium. This plant is mostly used as stakes in yam
production or in the construction of sheds which provide shade
during the dry season. The rapidly growing stems are
occasionally cut and laid on the ground for sheep and goats.
282
As pointed out in an earlier report (Adegbola and Asaolu,
1986), cassava peel is rapidly becoming an important by-product
for small ruminant feed. It is available from the local
processing of cassava root for "gari", a local fermented meal
product. It has also been observed that villages with
substantial numbers of small ruminants have experienced a boom
in sheep production especially where adequate browse is
available. Cassava peel is higher in crude protein than the
cassava root meal (Oyenuga, 1968).
Recently, a number of studies evaluating cassava peels in
comparison to maize-based diets have been reported in the
literature for poultry (Adeyanju and Pido, 1978), sheep
(Adebowale, 1981) and pigs (Obioha and Anikwe, 1982). However,
in none of these studies was cassava peel used as the main
energy source. The main objective here therefore was to study
the response of sheep to the use of cassava peel as the main
energy source using G I i r i c i d i a sepium as a supplement.
MATERIALS AND METHODS
In a 12-week feeding trial, twelve 5 to 7-month old animals,
consisting of six rams and six ewes, were randomly allotted to
three treatments of four replicates each. The animals were
dewormed and sprayed against ectoparasites before being
allotted to the treatments. The first diet was 100% G I i r i c i d i a
(leaves with dark and soft stems); the second diet was 80%
ensiled cassava peels plus 20% G I i r i c i d i a ; while the third diet
was 80% dried cassava peels plus 20% G I i r i c i d i a . Water and
mineral-salt licks were always provided for the animals. The
animals were adapted for 14 days to the experimental diets
prior to the commencement of the trial.
The cassava peels were obtained periodically from gari
processing plants in Oyo, and were derived from a bitter
variety of Manihot esculenta Crantz.
Fresh cassava peels were air-dried for 0, 2, and 4 days
before ensiling. It was shown that the most desirable odour and
the lowest pH was produced from peels dried for two days before
283
ensiling for 14 days (Table 1). This method was adopted for the
production of the silage used in the feeding experiment.
Subsequently, the peels were air-dried to about 60%
moisture content (Table 1) and ensiled in 200- litre drums which
had earlier been perforated at the bottom to permit adequate
drainage. The internal sides of the drums were lined with black
polythene sheets before filling with the wilted peels. The
peels were then compacted, covered with black polythene sheets
and weighted down with heavy stones. The silages were opened at
the end of 12 weeks.
Table 1. Optimum level of moisture in cassava peel to be
ensiled based on odour and pH.
Diets
a
Odour
(Score given) pH
1. 33.53% DM (fresh peel)
2. 60.28% DM (cassava peel after
2 days air-drying)
3. 85.47% DM (cassava peel after
4 days air-drying)
18 4.66
27 3.90
16 5.79
Key (a) ODOUR (30 points) Possible score
1. DESIRABLE: Clean, pleasant with no
indication of putrefaction 26-30
2. ACCEPTABLE: Somewhat strong, yeasty,
fruity or musty, slight burnt odour, sweet 16-25
3. UNDESIRABLE: Strong burnt or caramelised odour
indicating excessive heating.
Sliminess and a putrid odour indicate
improper fermentation. Very musty or mouldy
odour with excessive mould visible 5-15
284
Dried cassava peels were obtained after sun-drying fresh
peels for between 6-10 days depending on weather conditions,
without any problem of deterioration from fungal infection
(Table 2). The content of hydrocyanic acid (HCN ) in the fresh
peels, as well as dried and ensiled peels were determined using
the method of Grace (1977).
G I i r i c i d i a sepium was harvested daily from the University
Teaching and Research Farm.
Feed samples were collected for analysis at the start,
middle and end of the experiment, stored at -5 C, and pooled
for analysis.
All data were statistically tested using the Analysis of
Variance Method (Steel and Torrie, 1960), and significant
differences were subjected to Duncan's new Multiple Range Test.
RESULTS
Animals fed on G I i r i c i d i a alone consumed an average of
1044 g DM per day while those fed on the ensiled cassava peel
plus G I i r i c i d i a consumed 713 g DM per day and those fed on the
dried cassava peel plus G I i r i c i d i a consumed 642 g DM per day
(Table 3).
285
Table 2. Effect of sun-drying on the proximate composition of cassava
peels.
Proximate Drying period (days)
contents Standard
(%DH) 0 2 4 6 8 10 12 14 deviation
Dry-matter 33.53 60.28 85.47 84.73 85.18 87.34 86.59 87.0 +4.37
Crude fibre 20.50 21.65 22.00 21.90 21.65 21.80 22.0 21.50 +0.68
Ether extract 1.63 1.25 1.15 0.98 0.99 0.99 0.88 0.90+0.48
Ash 3.50 4.32 4.38 3.95 3.50 4.0 3.50 4.18 +0.59
Crude protein 2.80 2.10 2.67 2.59 2.18 2.43 2.75 2.34 +0.49
Nitrogen-free
extractive 71.57 70.68 69.45 70.58 71.68 70.78 70.87 71.08 +0.80
Energy
(kcal/g) 4.76 4.67 4.67 4.65 4.67 4.68 4.66 4.67 +0.18
286
Table 3. Dry-matter intake-an rate of gain of sheep after 12
weeks.
Average rate of gain Average dry-matter
Diet (gm/animal/day) intake (gm/animal/day)
Gliricidia 106.41a( 3.87) 1044. 24d( 28.70)
80% dried
cassava peel
+ 20% Gliricidia 59.20b(5.78) 642. 14e(47.07)
80% ensi led
cassava peel
+ 20% Gliricidia 80.89C(4.03) 713. 97f (47.75)
Different low case superscripts in the same column, indicate
significant differences (P< 0.05).
The daily rate of gain was 106 g/day for animals fed on
Gliricidia alone while those on the Gliricidia fodder plus
ensiled cassava peel gained 81 g/day, about 37% more than their
counterparts fed on the dried cassava peels with Gliricidia
which gained 59 g/day.
It was also observed that animals fed on the dried cassava
peel plus Gliricidia diet consumed the diet in the proportion
of 64:36, and not in the ratio of 80:20 offered. On the other
hand, animals fed on the ensiled cassava peel plus Gliricidia
consumed the diet in the proportion of 73:27, which is close to
the ratio in which the feed was offered.
DISCUSSION
The observed higher intake recorded for animals on the ensiled
cassava peel diet may be due to a lower content of prussic acid
in the ensiled cassava peel compared with the dried peel.
Analysis showed that while the fresh peel contained 956 mg
287
HCN/kg DM, the dried peel contained 378 mg HCN/kg DM. The
ensiled peel contained only 162 mg HCN/kg DM (Table 4). Thus,
while drying reduced the HCN content of cassava peel by 60%,
ensiling reduced it by 83%. The observed higher intake may also
be due to the sweet and pleasant acid (lactic acid) smell of
the cassava peel silage. Morrison (1959) had pointed out that
silages, even from plants with coarse stalks such as corn and
the sorghums, are eaten practically without waste. On the other
hand, a considerable part of the dry corn or sorghum fodder is
usually wasted, even if it is of good quality.
Table 4. HCN content of fresh cassava peels, dried
cassava peels and ensiled cassava peels.
Cassava peels HCN content
(mg HCN/kg DM)
1. Fresh 956
2. Ensiled 162
3. Dried 378
The high level of intake of G I i r i c i d i a sepium as well as
its high nutritive value (Carew, 1982; Mba et al, 1982) were
responsible for the faster growth rates of the animals fed on
G I j r i c i d i a alone.
The growth rates recorded for animals on the cassava peel-
based diets were significantly lower (P< 0.05) than those for
animals on G I i r i c i d i a .
CONCLUSION
From the results so far obtained, it is suggested that ensiled
cassava peel supplemented with G I i r i c i d i a sepium can be fed in
a production diet to West African Dwarf sheep with no adverse
effects on animal performance.
288
REFERENCES
Adebowale, E.A. 1981. The maize replacement value of fermented
cassava peels (Manhihot ut i I i ssima Pohl) in rations for
sheep. Tropical Animal Production 6: 54-69.
Adegbola, A. A. and Asaolu, V.O. 1986. Preparation of cassava
peels for use in small ruminant production in western
Nigeria. In: T.R. Preston and M.Y. Nuwanyakapa (eds),
Towards optimal feeding of agricultural by-products to
livestock in Africa. Proceedings of a workshop held at
the University of Alexandria, Egypt, October 1985. ILCA,
Addis Ababa, Ethiopia. pp. 109-115.
Carew, B.A.R. 1982. Uses of G I i r i c i d i a sepium as a forage feed
in small ruminant production - A progress report. ILCA,
Ibadan.
Grace, M.R. 1977. Prussic (hydrocyanic) acid analysis.
Quantitative determination by alkaline hydrolysis method.
In: Cassava processing. Plant Production and
Protection Series No. 3. Post Harvest Institute
Information Centre, Rome.
Mba, A.U.; Mangui, S.A. and Awah, A. A. 1982. Influence of
concentrate supplementation with browse plant ( G I i r i c i d i a
sepium) on nutrient utilization and growth of the West
African Dwarf (Fouta Djallon) kid. Nigerian Journal
Animal Production 9 (2): 63-73.
Morrison, F.B. 1959. Feeds and feeding. Morrison Publishing
Company, New York.
Obioha, F.C. and Anikwe, P.C.N. 1982. Utilization of ensiled
and sun-dried cassava peels by growing swine. Nutrition
and Reproduction International 26(6): 961-972.
Oyenuga, V.A. 1968. Nigeria's foods and feeding stuffs. Ibadan
University Press, Ibadan, Nigeria.
Steel, R.G.D. and Torrie, J.H. 1960. Principles and procedures
of statistics-a biometrical approach. McGraw-Hill Book
Co. New York.
289
UTILIZATION OF GLIRICIDIA SEPIUM AND CASSAVA PEELS
BY WEST AFRICAN DWARF (WAD) GOATS IN NIGERIA
0. J. Ifut
Department of Animal Science
University of Ibadan
Ibadan, Nigeria
ABSTRACT
Three diets - 100% Gliricidia sepium (T-1), 100% cassava peels
(T-2) and 70% Gliricidia sepium plus 30% cassava peels (T-3) -
were fed to 12 intact bucks of the West African Dwarf (WAD)
breed in a completely randomised experiment. Four bucks were
randomly assigned to each diet treatment. The experiment
lasted 90 days.
Treatment effect on dry-matter intake (DMI) was
significant (P<0.05). Goats on T-3 consumed the highest dry
matter (DM), organic matter (OM), nitrogen (N), acid-detergent
fibre (ADF) and neutral -detergent fibre (NDF), digestible DM
(DDM), digestible OM (DOM), digestible ADF (DADF) and
digestible NDF (DNDF) while those on T-2 consumed the least.
Goats on T-1 had the highest digestible N intake (DNI).
Goats on T-3 digested DM, N, ADF and NDF most (P<0.05);
those on T-2 digested OM most; they also had negative N
digestibility and digested ADF and NDF least (P<0.05). Goats
on T-1 digested DM and OM least (P<0.05).
The highest (P<0.05) body weight gain was by goats on T-
3 while those on T-2 were losing weight daily.
Gliricidia sepium was the most and cassava peels the
least (P<0.05) efficiently utilized as sole diets by goats.
Estimated meat yield per treatment was highest for
animals on T-3.
290
The intake, digestibility and utilization for weight
gain of G I i r i c i d i a sepium by goats were increased by
supplementation with cassava peels.
INTRODUCTION
Goats are one of the few important trypanotolerant livestock
species in the humid zone of Nigeria. Many households in the
humid parts of Nigeria keep an average of 4 to 5 goats while
larger numbers are kept in the savanna parts of the country.
The estimated goat population in Nigeria is 26.0 million (FAO,
1985).
One major constraint to goat production in Nigeria is the
low level of available nutrients. The extent to which feed is
available is a limitation to livestock production industry in
Nigeria (Adegbola, 1982; Olubajo and Oyenuga, 1974).
Gliricidia sepium is a fast-growing, perennial, leguminous
browse plant whose other desirable characteristics have been
documented by Thomas (1961), Chadhokar (1982), Falvey (1982)
and Sumberg (1984). Its utilization as livestock feed started
receiving attention in Nigeria only fairly recently, for
example by the International Livestock Centre for Africa (ILCA,
1983), Ademosun et al (1985), Mba et al (1982) and Onwuka
(1983). It has 17.4 - 34.5% DM on 'as fed' on fresh basis;
other contents on DM basis are OM (81.9 - 92.3%), crude protein
(CP) (19.4 - 26.1%), NDF (30.8%), ADF (18.5 - 44.4%), crude
fibre (CF) (12.7 - 32.5%) and lignin (7.3 - 29.6%) as reported
by King (1986), Ngone (1985), Mani (1984), Onwuka (1983),
Chadhokar and Sivasupi ramaniam (1983), Carew (1983), Gbankoto
(1982) and Oakes and Skov (1962).
Cassava peels are a major by-product of the cassava tuber
processing industry. In parts of Nigeria where cassava is
grown and the tubers processed, the peels are largely un - or
under-exploited as livestock feed. Cassava peels have been
reported to have the following composition: residual DM, 86.5
to 94.5%; OM, 89.0 to 93.9%; CP, 4.2 to 6.5%; and CF 10.0 to
291
31.8% (Onwuka, 1983; Carew, 1982; Adegbola, 1980; and Oyenuga,
1968).
The average intake of G I i r i c i d i a by goats has been
reported as 21.3 (range = 10.8 to 31.8) g.kg" ' .d" DM
(Ademosun et al, 1985; Onwuka, 1983; Carew, 1983). Mba et al
(1982) reported intake values ranging from 31.4 to 50.2% for
kids on G I i r i c i d i a while Onwuka (1983) reported gains of 20
g.d for goats on sole G I i r i c i d i a diet.
Information on intake and utilization of cassava peels and
G I i r i c i d i a fed together to goats is rather scanty. The
perennial and multipurpose nature of G I i r i c i d i a and
underut i I i zation of cassava peels as goat feed, formed the
basis of the present study. The research was, therefore,
undertaken to investigate the influence on intake,
digestibility and utilization of cassava peels with G I i r i c i d i a
sepium fed to WAD goats.
MATERIALS AND METHODS
Animals and their management
Twelve intact bucks, aged 6 to 9 months and weighing an average
of 6.05 kg (range = 5.0 to 10.0 kg), from the University of
Ibadan Teaching and Research Farm, were first rid of their
internal and external parasites using appropriate drugs. They
were then housed in previously disinfected individual
metabolism cages. They were offered liberal but known
quantities of the experimental diets daily for a 21-day
preliminary period to adapt the animals to the diets and the
cage environment.
Cool fresh water and salt lick were offered free choice in
the cages. During this period, the daily voluntary feed intake
was determined. Total faeces and urine from the experimental
animals were collected during the next 7 days (day 22-28) and
the last 7 days (day 84 - 90). Confinement and feeding
continued to day 90. Animals on diet T-2 were removed from the
experiment after day 28 in order to save the animals from
292
imminent death due to excessive loss of body weight. The
animals were weighed once a week (on the same day of every week
at about the same time of day) in the morning before feeding
and watering so as to minimise error due to "gut fill".
Feeds
Fresh G I i r i c i d i a sepium branches (about 1.2 m long and 1.5 cm
thick) with leaves and branchlets were obtained daily from
ILCA, Ibadan, between April and July, 1985. Cassava peels were
obtained fresh from local cassava grating plants in and around
the University of Ibadan campus. The cassava peels were sun-
dried for 3 to 4 days, depending on the intensity of the sun,
packed into jute bags and stacked away in the store on some
raised wooden planks until required for feeding.
Diets
The diets fed to the goats were 100% G I i r i c i d i a sepium (T-1),
100% sun-dried cassava peels (T-2) and 70% (w/w) fresh
G I i r i c i d i a sepium plus 30% cassava peels (T-3). The amount of
each diet offered to each experimental animal ensured a 5%
leftover. Residues were collected after a 24 h feeding,
weighed and the voluntary intake determined.
Sampling of the feeding stuff
Samples of G. sepium and cassava peels offered and rejected
during the collection period were taken daily dried and stored
in bottles fitted with air-tight screw caps and kept in a dark
cupboard until required for analysis.
Faecal collection
Total faeces were collected in the mornings before feeding and
watering during day 22-28 and the last 7 days of the
experiment. The two 7-day faecal samples for each experimental
animal were thoroughly mixed, milled in a laboratory hammer
mill to pass a 0.6 mm sieve and put in sealed polythene bags.
These were then stored in a cupboard at room temperature until
293
required for analysis. 5 g of the milled faeces were dried in
an oven at 100-105°C for 48 h to determine residual moisture.
Urine collection
Total urine excreted by each experimental animal was collected
daily in the morning before feeding and watering and stored in
a deep freezer at -5°C. At the end of the 7-day collection
period the sample collections were bulked for each animal and
subsamples taken for analysis.
Analytical procedure
Chemical
The milled samples of G I i r i c i d i a . cassava peels and faeces were
analysed for DM, OM and N according to A.O.A.C. (1975)
procedures and ADF and NDF according to the methods of Goering
and Van Soest (1970) and Van Soest and Robertson (1980).
RESULTS AND DISCUSSION
The chemical composition of the experimental diets is shown in
Table 1. The chemical components of G I i r i c i d i a and cassava
peels of this study compared favourably with values reported in
literature (Adegbola, 1980; Oyenuga, 1968, Onwuka, 1983; Carew,
1983; Chadhokar et al, 1983).
Intake
The DM and nutrients intake by WAD goats is summarised in Table
2. The highest DM and nutrient intakes were from T-3 diet
probably because the combination was palatable. The lowest DM
intake (DMI) from the peels (T-2) could possibly not be due to
the ADF and NDF content because these were lowest for the
peels. An inverse relationship has long been reported between
the DMI and the fibre content of feeds (Reid and Klopf enstein,
1983; Leaver, 1974). The lignin content of the peels could
also apparently not be responsible for the least DMI from T-2
because lignin content was highest in Gliricidia and 1.6 times
294
that of the peels (Table 1). The least DMI from T-2 was
probably due to the lowest N content of the peels. This is
supported by Rajpoot et al (1981), Malechek and Provenza (1981)
and Preston and Leng (1986) who had earlier reported that the
low N content of feeds significantly (P<0.05) reduced the DMI
of such feeds. The present study, however, seemed to indicate
that the relationship between dietary N content of feed and the
feed DMI per metabolic size was rather weak (r=0.03, P>0.05).
Nonetheless, the positive though weak relationship between N
(or CP) and DMI of diet was similar to the much higher r=0.86
(P<0.01) reported by Lippke (1980).
Table 1. Chemical composition of G I i r i c i d i a sepium and cassava
peels diets fed to West African Dwarf goats.
Chemical Diets
component T-1 T-2 T-3
DM
'As fed' SD 31.04 + 0.58 86.41 + 0.17 47.65 + 0.46
Residual SD 87.27 + 0.58 87.28 + 0.17 87.27 + 0.46
On DM basis SD
OM SD 91.25 + 1.29 89.25 + 1.84 90.66 + 1.46
ADF SD 28.27 + 3.65 23.85 + 3.52 26.95 + 2.98
NDF SD 41.45+3.43 34.27+4.33 39.30+3.70
N SD 3.76 + 0.05 0.96 + 0.38 2.92 + 0.15
Lignin SD 13.64+6.55 8.39+4.15 12.07+5.85
When dietary N content was correlated with the absolute
DMI of the animals, the relationship was highly significant
and negative (r= -0.43, P< 0.01). This seems to make some
(biological) sense in terms of nutrient density of the diet
because it suggests that an animal offered a low-N diet would
tend to consume more of the diet in order to derive more of the
needed N from the feed. However, this argument was not
supported in the present study because the lowest DMI (Table 2)
was recorded for goats on the lowest N-containing diet (T-2).
Neither was the linear relationship between N and DMI per
metabolic size of goats impressive nor significant (P>0.05).
295
Table 2. Dry-matter and nutrients intake (g.kg* " .d )* by
West African-Dwarf goats fed G I i r i c i d i a sepium and
cassava peels.
Intake of Treatment
nutrient 12 3
Dry-matter intake 46.30b 41.45b 76.01a
Organic-matter intake 42.95b 37.69b 67.50a
Nitrogen intake 1.80a 0.43b 1.48a
Acid detergent fibre intake 18.69a 8.30b 20.45a
Neutral detergent fibre intake 27.69b 10.94c 36.89a
* Means with the same letter in each row are not
significantly different (P>0.05).
The significance of the relationship between dietary N
and DMI might be through the indirect involvement of dietary N
with DM digestibility (DMD). Low N in feeds affects nutrient
balance which itself affects digestibility and, therefore,
intake. Thus, the less the N content of a feed, the lower the
level of its consumption, the poorer the balance of nutrients,
the slower the rate of its digestion, and the longer it remains
in the gastro-intestinal tract. Preston and Leng (1986)
suggested a probable complication of N in rumen ammonia
production level and microbial growth and activity.
The present result, therefore, suggests that it is
unreasonable to feed sun-dried cassava peels as sole diet to
domestic animals, especially goats.
Digestibi I i ties
The apparent digestibility coefficient (ADC) for DM and other
nutrients are presented in Table 3. The DMD of T-2 and T-3 was
296
similar (P>0.05) but significantly different (P<0.05) from that
of T-1. The rather low (54.2%) DMD and OMD (56.8%) recorded
for goats on T-1 was close to 57.1% DMD reported by Onwuka
(1983) who fed only dried leaves of G I i r i c i d i a to WAD goats.
This could have been due to its highest lignin content (Table
1). This is supported by McDonald et al (1973) and Nastis and
Malechek (1981) who concluded that lignin generally lowered
feed DMD. The highest DM and OM digestibilities of T-2 were
probably due to its lowest intake since digestibility and
intake are inversely related (Van Soest, 1982; Wagner and
Loosli, 1967).
Diets had significant influence (P<0.05) on N-
digestibi I i ty. The N in T-3 was digested most. This suggested
that the fermentable OM in the peels apparently encouraged
higher N digestibility (McDonald et al, 1973).
Nitrogen digestibility of T-2 was negative due, probably,
to the low N content (Table 1) of the peels. This is because
ADC of dietary N is, to a large extent, dependent upon the
proportion of N in the feed. Consequently, T-2 actually
reduced the digestible N supply of the goats (McDonald et al,
1973). Also the level of N ADC could have been due to the
level of feed intake (Owens and Berger, 1983).
The ADF of T-1 and T-3 was digested by goats to about the
same extent (Table 3). The NDF digestibility by goats on T-1,
T-2 and T-3 was, however, significantly different (P<0.05).
The high NDF ADC by animals on T-3 tended to suggest that NDF
was digested better when both G I i r i c i d i a and cassava peels were
fed simultaneously in the ratio of 7:3.
297
Table 3. Dry-matter and nutrients digestibility coefficients
(%)* by West African Dwarf goats fed G I i r i c i d i a
sepium and cassava peels.
Digestibi Ity coefficient (%)
Nutrient T-1 T-2 T-3
Dry-matter digestibi lity 54.21b 71.95a 74.34a
Organic matter digestibility 56.78b 77.35a 76.57a
Nitrogen digestibility 56.50a -6.40b 57.30a
Acid-detergent fibre digestibi I ity 42.89a 33.38b 46.15a
Neutral-detergent fibre digestibi lity 48.22b 36.61c 67.67a
* Means with the same letter in each row are not significantly
different (P>0.05).
The digestible DM intake (DDMI) and intake of other
digestible nutrients by goats is summarised in Table 4. The
DDMI was significantly different (P<0.05) for all dietary
treatments. The highest DDMI value of 56. 4g. kg ' .d was
recorded for goats on T-3. The superiority of T-3 over T-1 and
T-2 was observed in the amount of DOM and DM consumed from the
diets. This suggested that supplementation of G I i r i c i d i a with
cassava peels was beneficial to goats. It is, therefore,
suggested that G I i r i c i d i a and cassava peels, when they must be
fed to goats, be offered in suitable proportions to ensure
maximum utilization of the feeding stuffs.
298
25.38b 31.08b 56.44a
24.84b 29.17b 51.66a
1.03a -0.03b 0.85a
8.15a 2.68b 9.44a
13.80a 4.22b 24.93a
Table 4. Digestible dry-matter and nutrient intake (g.kg .d
)* by West African Dwarf goats fed G I i r i c i d i a sepium
and cassava peels.
Component Treatment
intake 1 2 3
Digestible dry-matter intake
Digestible organic matter intake
Digestible nitrogen intake
Digestible acid-detergent fibre
intake
Digestible neutral detergent fibre
intake
* Means with the same letter in each row are not significantly
different (P>0.05).
Nitrogen utilization and body weight changes as well as
efficiency of feed utilization and estimated meat yield by
goats on the experimental diets are shown in (Tables 5 and 6)
respectively. N-balance among goats on T-1 and T-3 was similar
(P>0.05); that of T-2 was negative (-0.04 g.kg"°"75.d"1)
probably due to the low N content (Table 1) of T-2 and the
negative DNI (Table 4) from T-2. Consequently, the goats on T-
2 were losing an average of 54.8 g daily and the trial had to
be suspended after the initial collection period. It is,
therefore, unreasonable and uneconomical to feed sole cassava
peels diets to goats. Goats on T-3 were superior to those on
T-1 (54.2 versus 50.0 g.d ) in average daily weight gain.
This could probably have been due to a better balance of
nutrients resulting from the feeding of G I i r i c i d i a and cassava
peels simultaneously in the ratio of 7:3.
299
Table 5. Nitrogen utilization (g.kg ' .d )* and body weight
changes (g.d ) in West African Dwarf goats fed
G I i r i c i d i a sepium and cassava peels.
Treatment
G I i r i c i d i a 100% 70/30
Nitrogen intake 1.80a 0.43b 1.48a
Faecal N Loss 0.77a 0.45b 0.63a
Absorbed nitrogen 1.03a -0.03b 0.85a
Urinary N loss 0.26a 0.02b 0.07b
Nitrogen balance 0.77a -0.04b 0.78a
Body weight change 50.0b -54.77c 54.16a
* Means with the same letter in each row are not significantly
different (P>0.05).
In Nigeria the average annual yield of cassava tubers is
21.1 t.ha' (Hahn and Chukwuma, 1986). Since the peels
constitute 20. 0% of the tuber (Hahn et al, 1986), this means
that about 4.22 tonnes of cassava peels per hectare are
available annually for feeding ruminants, especially goats.
The inclusion of 30% or less (depending on availability) of
such peels would support weight gains as shown in Table 6 among
goats. For example, a 6-month-old goat weighing 6.1 kg
initially, when fed a T-3 diet containing 70% Gliricidia and
30% cassava peels and gaining an average of 54.2 g.d for one-
year would weigh 25.9 kg at the end of the period, thus gaining
19.8 kg. This 25.9 kg goat, one and half years old, would
have, at 51% dressing percentage (Akinsoyinu, 1974), a carcass
weight of 13.2 kg which is equivalent to the edible goat meat
for the one-year growth period.
300
46.30 41.45 76.01
50.99 -54.77 54.16
0.91b -0.76c 1.40a
18.6 -20.0 19.8
9.5a -10.2b 10.1a
Table 6. Efficiency of feed utilization* and estimated goat
meat yield (kg.yr )* among West African Dwarf goats
fed Gliricidia sepium and cassava peels.
Treatment
Dry-matter intake (g.kg ' .d )
Body weight change (g.d )
Feed efficiency
Weight gain (kg.yr )
Estimated meat yield (kg.yr )
* Means with the same letter in any row are not
significantly different (P>0.05).
Earlier workers have indicated inclusion of cassava peels
to varying degrees in livestock feeds. Adegbola (1980)
concluded that 10% cassava peels meal inclusion in pig ration
induced fastest rate of gain and highest feed conversion
efficiency. Onwuka (1983), on the other hand, concluded that
25% cassava peels:75% browse was the best proportion for goats
in terms of intake, digestibility and other performance
parameters. In the present study, a 30% level of cassava peels
has been shown to be beneficial to goats. These studies
suggest that the actual amount of cassava peels suitable for
inclusion in goat feeds is a subject for further research.
Ensiling of cassava peels as a means of preservation and the
nutritional value of the product should be given research
attention.
Further research work is needed to relate annual yields of
Gliricidia and cassava peels fed as sole or combined diets to
the production of goat meat from such diets in Nigeria.
301
CONCLUSION
G I i r i c i d i a was richer in and, therefore, a better source of
dietary N than cassava peels when the two feedingstuf f s were
fed either as sole or combined diets to goats.
Sun-dried cassava peels were easier to pack and kept
longer in storage.
Feeding G I i r i c i d i a and cassava peels in a 7:3 ratio
encouraged maximum intake, digestibility, utilization and
highest body weight gain.
ACKNOWLEDGEMENTS
I wish to thank ILCA, Ibadan, Nigeria for making Gliricidia
used in this study available and Drs. J. A. Adeneye and A.O.
Akinsoyinu, both of the Department of Animal Science,
University of Ibadan, Nigeria for their suggestions and
criticisms.
REFERENCES
Adegbola, A. A. 1980. New feed resources for Nigerian
livestock. Disc. Niger. Acad. Sci. 2(2): 50-63.
Adegbola, A. A. 1982. Forage resources and beef production in
Nigeria. Proc. National Conf. Beef Production, Kaduna,
Nigeria July 27-30, 1982. Publ. NAPRI, Shika, Zaria,
Nigeria. pp. 137-165.
Ademosun, A. A.; Jansen, N.J. and Houtert, V. 1985. Goat
management research at the University of Ife. In: J.E.
Sumberg and K. Cassaday (eds), Sheep and goats in humid
West Africa. Proceedings of the Workshop on Small
Ruminant Production Systems in the Humid Zone of West
Africa, Ibadan, Nigeria, 23-26 Jan. 1984. ILCA, Addis
Ababa, Ethiopia. pp. 34-37.
Akinsoyinu, A.O. 1974. Studies on protein and energy
utilization by WAD goats. Ph.D. thesis, University of
Ibadan, Dept. of Animal Science, Ibadan, Nigeria.
302
AOAC (Association of Official Analytical Chemists). 1975.
Official methods of analysis. 12th ed. AOAC,
Washington, D.C.
Carew, B.A.R. 1982. Free choice response of extensively
managed goats in a tropical environment. Humid Zone
Programme -Document No. 8. ILCA, Ibadan, Nigeria.
Carew, B.A.R. 1983. G I i r i c i d i a sepium as a sole feed for small
ruminants. Trop. Grass. 17(4): 181-183.
Chadhokar, P. A. 1982. G I i r i c i d i a maculata: A promising legume
fodder plant. World Anim. Rev. 44: 36-43.
Chadhokar, P. A. and Sivasupi ramaniam, S. 1983. Gliricidia
( G I i r i c i d i a maculata H.B. and K.) leaves as protein
supplement to paddy straw in growing crossbred heifers.
Indian J. Anim. Sci. 53(2): 120-125.
Falvey, J. L. 1982. Gliricidia maculata-a review. Int. Tree
Crops J. 2: 1-14.
FAO (Food and Agriculture Organization of the United Nations).
1980. Trade Year Book. FAO, Rome.
Gbankoto, A.O. 1982 Nutritive value of feedingstuf fs: Intake
and digestibility by White Fulani (Zebu) steers of fresh
grass, grass hay, agro- industrial by-products and
Gliricidia sepium. Ingenieur Agronome (Animal Husbandry)
thesis, Univ. of Ibadan, Ibadan, Nigeria.
Goering, H.K. and Van Soest, P.J. 1970. Forage fibre analysis
(apparatus, reagents, procedures and some applications).
Agric. Handbook, 379. USDA, Washington, D.C.
Hahn, S.K. and Chukwuma, E.M. 1986. Uniform yield trials. In:
IITA (International Institute of Tropical Agriculture)
Annual Report 1985. IITA, Ibadan, Nigeria.
ILCA (International Livestock Centre for Africa). 1983. Annual
Report, 1983. ILCA, Addis Ababa, Ethiopia. pp. 8-14.
King, E.A. 1986. Gliricidia sepium leaves and yam peels as
feed for weaned calves. M.Sc. dissertation, Univ. of
Ibadan, Dept. of Animal Science, Ibadan, Nigeria.
Leaver, J.D. 1974. Rearing of dairy cattle. 5. The effect of
stocking rate on animal and herbage production in a
grazing system for calves and heifers. Anim. Prod.
18: 273-284.
303
Lippke, H. 1980. Forage characteristics related to intake,
digestibility and gain by ruminants. J. Anim. Sci.
50(5): 959.
Malechek, J.C. and Provenza, F.D. 1981. Feeding behaviour and
nutrition of goats on rangelands. In: P. Morand-Fehr, A.
Bourbouze and M. de Simiane (eds), Symposium
international sur les productions caprines, nutrition et
systemes d'al imentation. Tours, France, May 12-15, 1981.
Institut technique d'elevage ovin et caprin; Institut
national de la recherche agronomique, Paris, France.
Vol. 1. pp. 411-428.
Mani, R.A. 1984. Browse selection and intake behaviour of West
African Dwarf sheep and goats. M.Sc. thesis, Dept. of
Animal Science, Univ. of Ibadan, Ibadan, Nigeria.
Mba, A.U.; Manigui, S.A. and Awah, A. A. 1982. Influence of
concentrate supplementation with browse plant (Gliricidia
sepium) on nutrient utilization and growth of the West
African Dwarf (WAD) (Fouta Dial Ion) kids. Nig. J. Anim.
Prod. 9(2): 63-73.
McDonald, P.; Edwards, R.A. and Greenhalgh, J. F.D. 1973.
Animal nutrition. 2nd ed. Oliver and Boyd, Edinburgh.
Nastis, A.S. and Malechek, J.C. 1981. Digestion and
utilization of nutrient in oak browse by goats. J.
Anim. Sci. 53(2): 283-290.
Ngone, M.M. 1985. J_n vivo digestibility of Gliricidia sepium
fed to adult West African Dwarf sheep. M.Sc.
dissertation, Univ. of Ibadan, Dept. of Animal
Science, Ibadan, Nigeria.
Oakes, A.J. and Skov, 0. 1962. Some woody legumes as forage
crops for dry tropics. Tropical Agriculture 39: 281-287.
Olubajo, F.O. and Oyenuga, V.A. 1974. The yield, intake and
animal production of four tropical grass species grown at
Ibadan. Niger. J. Anim. Prod. 1(2): 217-224.
Onwuka, C.F.I. 1983. Nutritional evaluation of some Nigerian
browse plants in the humid tropics. Ph.D. thesis,
University of Ibadan, Department of Animal Science,
Ibadan, Nigeria.
304
Owens, F.N. and Bergen, N.G. 1983. Nitrogen metabolism of
ruminant animals: historical perspective, current
understanding and future implications. J. Anim. Sci.
Vol. 57, Suppl. 2:498-518.
Preston, T.R. and Leng, R.A. 1986. Matching livestock
production systems to available resources. Pretesting
edition. ILCA, Addis Ababa, Ethiopia.
Rajpoot, R.L.; Sengar, O.P.S. and Singh, S.N. 1981. Energy and
protein in goat nutrition. In: P. Morand-Fehr, A.
Bourbouze and M. de Simiane (eds). Symposium
international sur les productions caprines, nutrition et
systemes d'al imentat ion, Tours, France, May 12-15, 1981.
Institut national de la recherche agronomique, Paris,
France. Vol. 1. pp. 101-124.
Reid, R.L. and Klopfenstein, T.J. 1983. Forages and crop
residues: quality evaluation and systems of utilization.
J. Anim. Sci. Vol. 57, Suppl. 2: 534-562.
Sumberg, J.E. 1984. Collection and initial evaluation of
G I i r i c i d i a sepium from Costa Rica. Small Ruminant
Programme, ILCA, Ibadan, Nigeria.
Thomas, C.A. 1961. G I i r i c i d i a sepium has many uses. Indian
Farming 11(4): 13.
Van Soest, P.J. and Robertson, J.B. 1980. Systems of analysis
for evaluating fibrous feeds. In: W.J. Pigden, C.C.
Balch and M. Graham (eds), Standardization of
analytical methodology for feeds. Proc. Workshop, Ottawa,
Canada, 12-14 March 1979. IDRC (International
Development Research Centre), Ottawa, Ontario. pp. 46-60.
Wagner, D.G. and Loosli, J.K. 1967. Studies on the energy
requirements of high -producing cows. Cornell University
Agric. Expt. Sta. Memoir, 400. Ithaca, New York.
305
EVALUATION OF CASSAVA FLOUR AND GROUNDNUT CAKE AS CONCENTRATE
SUPPLEMENTS FOR WEST AFRICAN DWARF GOATS
R.M. Njwe1 and F.O. Olubajo2
1
Dept. of Animal Science, Dschang University Centre
B.P. 96, Dschang, Cameroon
2
Dept. of Animal Science, University of Ibadan
Ibadan, Nigeria
ABSTRACT
Forty-eight West African Dwarf goats ranging from 9 to 12
months and weighing between 9 and 15 kg were fed fresh
Guatemala grass and various combinations of graded levels of
cassava flour (0, 100, 150 and 200 g/day) and groundnut cake
(0, 50, 100, and 150 g/day) as concentrate supplements in a
split -plot design.
Incorporating increasing combined levels of both
supplements in goat rations increased dry-matter, crude protein
and cell contents intake; and decreased intake of cell walls,
acid detergent fibre and cellulose. While it positively
affected the digestibility of dry matter, crude protein and
cell contents, the effect on cell walls, acid detergent fibre
and cellulose digestibilities was negative.
Each increment in the level of groundnut cake and
cassava flour in goat rations resulted in an increase in
liveweight gain. Maximum liveweight gain was obtained with
animals fed either a combination of 200 g of cassava flour with
100 g of groundnut cake (52 g/day) or 200 g of cassava flour
with 150 g of groundnut cake (62 g/day) as supplement to fresh
Guatemala grass.
Goats receiving 0 to 50 g concentrate supplement lost
weight consistently as a result of inadequate energy and
protein intakes.
306
INTRODUCTION
Nutrition is one of the major factors responsible for the low
productivity of small ruminants in Cameroon. Generally,
undernutrition is more acute in the dry season than the wet
season. Many agricultural and agro- industrial by-products are
available but are not fully exploited for the feeding of
livestock. Among these products are cassava flour and
groundnut cake. For profitable use of these products as
concentrate supplements for livestock, optimum levels have to
be determined through feeding trials. The objective of this
experiment was to determine the optimum combination of
groundnut cake and cassava as concentrate supplements to adult
West African Dwarf goats.
MATERIALS AND METHODS
Forty-eight West African Dwarf goats ranging from 9 to 12
months and weighing between 9 and 15 kg were used for this
experiment. They were previously maintained on Guatemala grass
and limited quantities of concentrate at the University farm at
Nkolbisson. Deworming and tick control was carried out before
the experiment began.
The animals were divided into 16 groups, represented a
treatment in a split-plot design consisting of four main plots
(cassava flour levels) and 4 subplots (groundnut cake levels).
Fresh Guatemala grass (Tr ipsacum laxum) was fed in
different combinations with cassava flour (0, 100, 150 and 200
g per animal per day) and groundnut cake (0, 50, 100 and 150 g
per animal per day). Each concentrate supplement contained
bicalcium phosphate at a rate of 1%. The chemical composition
of the experimental diets is shown in Table 1.
307
Table1.Ehemicalcompositionf00uatem agr ssandthexpe imentaldi ts.
COo CO
Energy| 00cal/g)|
4.63| 4.50| 4.54| 4.63| 4.74|
4.70| 4.65| 4.63| 4.33| 4.70| 4.52| 4.76|
%
Totalash
5.87 7.16 5.69 2.S 5.16 5.69 5.94 6.36 2.26 4.94 5.29 5.67
%
Eellulose
39.49 3.86 31.67 2.76 3.55 3.36 3.44 34.55 3.87 3.00 3.23 3.00
%
50lignin
8.00
0.90 6.88 0.E 0.E 0.83
0.81 9.58 0.E
0.82
0.55
0.90
%
AOF
E.30
4.76 38.55 3.55 3.97 4.19 4.S 43.76 4.66 3.88 4.00
4.15
% S
36.46 82.44 29.37 87.31 85.66 48.97 48.59 31.17 87.36 86.00 85.38 48.84
% 00
63.54 17.50 70.63 12.69 11.34 15.00 15.00 68.83
12.64 13.94 11.62 15.16
% 00 8.55 50.00
11.17 1.66 16.33
S.50
29.50 8.09 1.68 11.30 20.50
26.01
% EM
92.48 86.76 90.55 87.11 87.64 88.12 88.75 91.36 86.44 87.73 88.13 88.26
|00roundnut
|cake
IF1 IF2 |E1PO |E1P1 |E1P2 |E1P3 IF* |E2PO |E2P1 |E2P2 |E2P3
Eont'd
Table1.Ehemicalcompositionf00uatemalagrassandtheexp r entaldi t .
Energy| 00cal/g)|
4.66| 4.50| 4.54| 4.66| 4.44|
I%
|Totalash
|6.08
I2.17|
I5.S|
I5.E
I5.39|
%
Eellulose
38.58 2.75 2.98 3.16 3.S
I%
|50lignin
|6.70
|0.55
|0.85
|0.55 |0.55
%
AOF 45.28 3.53 3.83 3.50 4.04
% S
32.23 87.34 86.31 85.71 85.55
% 00
67.00 12.66 13.69 11.29 11.82
% 00 10.00
1.54 15.27 16.E 21.13
I%
|EM
|92.44 |86.13 |86.31 |86.88 |87.52
I I I
IF* |E3PO |E3P1 |E3P2 |E3P3
I
F1,23and4represent00uatemalagra sf tvariouspe iodofthexp r ent.
E1,2and3representth10052g/head/dayofcassavaflour.
P0,12and3representth0,51005g/head/dayofroundnutcake.
EM=drymatter
00=crudeprotein
00■cellwal s
S=cellcontents
50F=acid-detergentfib
50lignin=acid-deterge tl gnin.
COo
Animals were maintained in individual metabolic cages
during the entire experimental period of 42 days. Due to the
availability of only 12 metabolic cages, 4 treatments were run
at a time until the 16 treatments were completed. The daily
portion of concentrate was given in individual troughs at 08.00
hours while chopped fresh Guatemala grass was also offered in a
grass trough at 09.00 and 16.00 hours. Fresh drinking water
and salt licks were provided ad I ibi tum in all the cages. The
animals were weighed at weekly intervals during the
experimental period. During the last 7 days of the
experimental period faeces and urine were collected.
Dry-matter, ash and crude protein content of forage,
concentrates and faeces were analysed according to A.O.A.C.
(1970) methods; while cell contents, cell walls, acid-detergent
fibre, acid- detergent lignin and cellulose were analysed as
described by Goering and Van soest (1970). Urinary nitrogen
was determined by the macro-K jeldah I and Markam micro-
distillation method. Gross energy of feeds, faeces and urine
was determined with the Gallenkamp ballistic oxygen bomb
calorimeter. Methane energy production was estimated according
to the equation of Blaxter and Clapperton (1965) while
metabolic faecal nitrogen was analysed by the detergent method
proposed by Mason (1969). Statistical analysis of data was
carried out according to the procedures of Steel and Torrie
(1960) while differences between treatments were determined
using the least significance difference test.
RESULTS AND DISCUSSION
Table 2 presents dry-matter and nutrients intake by West
African Dwarf goats fed basal Guatemala grass and various
concentrate supplements. Generally as more concentrate was
consumed by goats there was a corresponding decrease in forage
dry-matter intake indicating a preference for concentrate
intake to grass.
310
An increase in the level of groundnut cake in
concentrate supplements increased total dry-matter intake by
goats. Animals offered 150 g (P) groundnut cake per day
consumed 63.16 g/day/W " kg compared to 58.80, 48.17 and
48.47 g/day/ W kg, respectively, for those fed 100 (P2) 50
(P1) and 0 (P0) grammes of groundnut cake per day. Dry-matter
intake by goats fed 200 g of cassava flour (E,) was 62.24
0 75 ■*
g/day/W " kg which was significantly (P<0.05) higher than all
the other treatments (En, E, and E0) with values ranging from
0 75 u 1 d
51.29 g/day/W ' kg. The inter action of cassava flour and
groundnut cake was not significant on dry-matter intake. Goats
fed mixed concentrate of 200 g cassava flour and 150 g
groundnut cake consumed the highest quantity of dry-matter
(72.88 g/day/W " kg). This value was not significantly
different from dry-matter intake by animals on supplements
consisting of a mixture of 150 g cassava flour and 150 g
groundnut cake (63.93 g/day/W " kg) or 200 g cassava flour and
100 g groundnut cake (69.39 g/day/W " kg) but significantly
(P<0.05) higher than all other treatments. The lowest levels
of dry-matter intake were obtained with animals fed Guatemala
grass only or supplemented with 50 g groundnut cake or either
100 or 150 g cassava flours; intake ranging from 43.98 to 49.51
g/day/W°'75kg.
311
Table2.FeedintakebyWestAfricandw rfgoa sfcombinatio sfg d dl velsr un ut
cake(P)andcassavaflourEconcentratesupplements.
TreatmentsEM00WS50F
Effectsof
groundnutcake
PQ48.EE13.S 94A23.9215 602 8 P148.17E6.5322 64B6 861 95S P258.55B19.69ES 1A.,34 3011 253 P363.16A112 39S.61.,38 701.SB
001.371982648
£EV(%)8.697 984311.7634
L004.010 542 401 95.E
Effectsofcassavaflour
E0 E1 E2 00 EV(%) L00
17.15A 9.19E 9.53E 10.65B
12.17BE
0.S
7.48 0.87
20.79A 11.45E 12.60B
0.26
6.00
0.92
23.68E 28.08E 31.73B 40.29A
0.51 5.72 1.00
33.22A 22.69A 21.46B 21.97B
0.E
6.58 1.64
8.50A 8.09A 7.12B 8.36A
0.55 7.E 0.63
52.28B 51.29B 52.79B 62.24A
0.82 5.20 2.48
Eont'd
Table2.FeedintakebyWestAfricandw rfgoa scom inatio sfg edl v lr undnut
cake(P)andcassavaflourEconcentratesupplements.
S
55.76a 15.06b
17.33ab 17.46ab
10.54cdef
8.90efg
9.24defg
8.04fg
10.31cdef 10.26cdef
7.37g
10.19cdef
E.63cd 8.06fg
12.17c
10.76cde
0.76
E.34
2.23
50F
a b
ab ab
cde def
cdef
ef
cde cde
f
cde
cd f c
cde
22.73 55.26 21.00 21.16 12.86 10.85 12.04 10.07 13.15 13.12
9.00 12.00
13.68 9.57 11.39 12.75 0.97 11.76 2.83
g g e
cb 21.27fg
e
cd
c
ef de
c b c c
ab
a
S
17.32 19.42 26.24 31.73
S.89
31.00
33.39
24.00 27.S
34.76 40.64
33.00
34.61 44.42
49.55
1.34 7.48 3.90
00
00.23a
28.98be 33.88ab
34.82a
24.39cd
21.39def
34.11cd
20.86def 21.57def
23.16d
17.60ef 23.70cd 22.57de 16.00f S.00cd 23.33d
1.64
E.43
4.E
00
gh ef
b a h f
cd
a i
fg cd
a
hi de 9.57be
a
4.55 6.50
10.28
12.00 3.55
6.38
8.S
E.87
2.57 5.39 8.59
E.95
3.36 7.78 12.75 0.37 7.98 1.08
EM
E.51efg
43.98g
55.58cde 62.00bed
45.66fg
E.28efg 55.64cde 54.Sdef
45.13fg
49.86efg
52.Sef
63.00abc 55.63cde 51.59efg
69.39ab
72.38a
2.74 8.69 8.02
Eombinations
Treatments
Po
P1 P2 P3
Po
P1 P2 P3
Po
P1 P2 P3
Po
P1 P2 P3 (%)
L00
Eo Eo Eo Eo
E1 E1 E1 E2 E2 E2 E9 E2 E3 E3 E3 E3 00
EV
CO
I—'
CO
N.B.Figuresincol mnw ththesalet rscriptar
notsignificantlyd fferent(P>0.55).
The overall mean total dry-matter intake of
54.51g/day/W " kg by goats from this investigation agree with
the 57.73g/day/W kg reported by Awah (1982) with goats of
similar age. The improvement in goats' dry-matter intake when
increased levels of either cassava flour or groundnut cake (or
both) were incorporated in their diets agrees with the findings
of Akinsoyinu (1974), Adegbola (1974), and Crabtree and
Williams (1971). The high levels of total dry-matter intake
with high levels of dietary crude protein agrees with reports
by several authors (Adegbola, 1974; Blaxter and Wainman, 1964;
Elliot and Topps, 1963).
The improvement in dry-matter intake is attributed to
the stimulating effect of the readily available concentrate
nitrogen on the multiplication, digestive and fermentative
activity of rumen microbial population. The larger surface
area for the activity of digestive enzymes and faster rate of
passage through the rumen and gut are factors that could
contribute to increased dry-matter intake when increasing
levels of concentrates are fed to goats.
Increasing the quantity of groundnut cake in diets
resulted in a corresponding significant (P<0.05) increase in
crude protein intake by goats from 3.47 (P ) to 12.39
0 75 °
g/day/W " kg (P,). The effect of increasing dietary levels
of cassava flour on crude-protein intake by goats was not
consistent. The interaction of cassava flour and groundnut
cake on crude protein intake was not significant. Maximum
crude-protein intake (12.99 g/day/W " ) was registered with
goats fed Guatemala grass and 150 g groundnut cake only (E P,),
while the lowest intake was obtained with those maintained on
grass supplemented with 150 or 200 g cassava flour (2.57 and
3.36 g/day/W " kg, respectively).
314
The increase in crude-protein intake as the level of
groundnut cake in goat rations was raised agrees with the
reports of Akinsoyinu (1974). The diminishing effect on crude-
protein intake by increasing levels of cassava flour may be a
result of a dilution effect or decreasing concentration of
crude protein per gram of concentrate consumed by goats.
Intake of concentrate supplement significantly (P<0.05)
depressed intake of cell walls by goats. The interaction of
cassava flour and groundnut cake on cell walls intake was
significant (P<0.05). Animals fed only forage had the highest
level of cell wall intake. The declining contribution of
forage to total dry-matter intake as concentrate level was
raised could be responsible for the lower cell walls intake by
goats fed mixed rations of forage and concentrate. The same
explanation is valid for the relatively higher intake of acid-
detergent fibre and cellulose by goats fed only grass compared
to those on diets of grass and concentrates.
Each increase in the level of groundnut cake or cassava
flour in goat diets caused significant (P<0.05) increases in
the intake of cell contents. This may be attributed to the
increasing importance of this fraction in the diet as more
concentrate was consumed. Cell contents constitute 82 to 87%
of concentrates used in this study.
The digestibility of dry-matter and other feed
constituents by dwarf goats is indicated in Table 3. The
digestibility of dry-matter, crude protein, cell contents and
energy was improved by feeding goats with combined graded
levels of cassava flour and groundnut cake; while that of cell
walls, acid-detergent fibre and cellulose was decreased. The
315
highest digestibility of dry-matter (76.04%) was obtained with
goats fed the highest levels of groundnut cake and cassava
flour (E,P,) while the least values were registered with goats
maintained on forage only (63.31%) or forage plus 50 g
groundnut cake (60.06%).
Incorporating increasing levels of groundnut cake in
goat rations resulted in corresponding increases in digestible
and metabol isable energy intake. Similarly, each increment in
cassava flour level in goat rations resulted-in an improvement
in digestible metabol isable energy intake (Table 4). Maximum
digestible energy intake was obtained with goats fed 150 a
groundnut cake with 200g cassava flour (235.69 Kcal/day/W * ),
whereas minimum intake was in goats fed forage only (131.56
Kcal/day/W " kg) or forage plus 50g groundnut cake (108.14
kcal/day/W0,75kg).
All animals gained weight except those fed forage only
or forage plus 50 g groundnut cake. Generally, increasing the
level of groundnut cake and cassava flour resulted in increased
weight gain. Liveweight loss recorded ranged from -4 g/day for
animals fed solely on forage to -11 g/day for those fed forage
and a supplement of 50 g of groundnut cake. The highest rates
of liveweight gain were observed with goats fed 200 g cassava
flour with 100 g groundnut cake (52g/day) and 200 g of cassava
flour with 150 g groundnut cake (60 g/day). These values were
significantly (P<0.05) higher than all other treatments. In
terms of weight gain, the advantage of these concentrate
supplements are obvious. Low energy intake and negative
nitrogen balance may be responsible for the liveweight losses
obtained with goats fed solely on forage or forage supplemented
with minimum does of groundnut cake.
316
Table3.EigestibilityXoff edconstituentsyWesAfr canEwarfoa scomb nationfa edlev
ofgroundnutcake(P)ancassavaflourEconcentratesupplement.
*
E9
67.52A1B1
66.91B1 69.87A1 69.6EA1
0.81 4.11 2.38
59.15B 70.60A 70.66A 73.58A
0.88
4.E
3.08
59.81f 52.55g 61.42f
62.81ef
A1 B1
51.E8A B1
B1 61.08A B B B a
abed
abe ab
E00
54.E8
E.78
49.44 1.76 11.72 5.11 45.55
E.00
49.79 1.22 8.29 4.23 64.50 58.28 60.10 61.43
A1 B1
A1B1
A1 A B B B a
abe ab ab
AEFE 53.16
45.00
49.24 45.90 1.81 12.01 1.81
59.00
00.31 46.51 45.49 1.53 10.93 5.29 64.90 55.62 57.42 58.16
74.86B1 73.16B A1 A1 74.34E E B A f
ef
abed abed
EEO 81.00
81.20 1.55 5.28 3.45 74.55 78.04
83.31 0.88 3.92 3.04 68.0E 70.24 78.53 78.34
*
E00
62.21A1 60.21A1 60.91A1 59.11A
1.22 7.55
3.50
62.65A 63.51A 61.64A 54.82B
1.40 8.01 4.86
66.20ab
59.49bed
61.70abed
63.00abe
*
EPE
55.49E1 74.04B1 78.48A1 79.50A1
0.71 3.45 2.08
70.89BE
71.70B 74.05A 69.33B
0.59 2.85 2.04
59.91i
70.17fgh
76.97bcde 79.55abed
cake
B1 C1 71.97A1 A1 E B 7 A
gh
h
fg ef
ofgroundnut 68.81
66.50
72.28 0.67 3.33 1.97
64.50 70.E
71.71 73.23 0.51 2.50 1.75 63.31
60.00
66.54 68.32
ES
of
flour
Eombinations
Treatment
Effects
EV(%)
Effects cassava
EV(%)
EoP
EoP1 EoP2 EoP3
Po
P1 P9 P3 00 L00
Eo
E1 E9 E3 00 L00
Eont'd
Table3.EigestibilityXoff edc nstituentsbyWe tAfr canEw rfgoatf dacomb n tionfgr dlev ls
ofgroundnutcake(P)ancassavafl rEncentr tesupplement.
67.70cde 74.11ab
71.27abed
69.30abede
69.00bede
68.48de 73.58ab 73.00ab 73.52ab 74.83a 73.21abe
72.76abe
E9
52.00bede 50.00bede
54.97abede 52.10bede
1.63 4.11 4.76
48.38cde
45.39e 44.74e 43.68e 43.57e 44.46e 43.90e
48.20de
E00
53.48abed 46.89bede 49.97bede 50.59bede
3.51 11.92 10.27
43.94cde*-■ 42.94de 42.06de 48.28e
42.88de 42.44de 38.66e
42.74de
AEFE
00.72abede
3.63 13.01 10.61
79.87def 70.48def 76.26cde 55.22abc 75.83cde 73.83cde
81.92ab 55.58ab 48.63ab 85.26a 85.64a
*- 5.28 2.36 6.91
CCE
64.59abe
59.20bed 63.93abc 60.Eabed
62.63abed 57.55bed 57.30bed 55.85cde
65.91ab 68.83a
54.71de 48.60e
2.64 7.55 7.72
E00
*
74.50efg 55.46abc
81.Eab 81.06ab
75.44def
75.88cdef
50.37j 57.42i 48.77a 82.94a 57.27i 68.71h
1.42 3.45 4.17
0000
71.22bcde
70.E1bedef
73.E4abed 73.67abed
68.72ef 70.55def
70.55def 67.90ef 74.90abe 68.19ef 75.22ab 76.04a
w
1.34 3.33
3.E3
ES
Treatment
EV(X)E1Po E1P E1P2 E1P3
E2Po E2P1 E2P coE2P3
"E3Po E3P1 E3P2 E3P
L0000
N.B:Figuresinacolumnw ththesa,letscr55tanotsignificantlyd ffe ent(P>0.5 ).
EME=dry-matterdigestibilityA FE=acid-de ergentf bdigestibili y
EPE=crude-proteindigestibilityE00=cellulosedigestib l ty
EWE=cell-walldigestibi ityENE=nergydigestib l t
*
00E=eelI-contentsdigestibility
GO
i— U3
Table4.EnergyintakendlivweightgainbyW stAfricadw rfgoa sdcombit onsof gradedlevelsofoundnutc k(P)ancassavaflourEco centratesupplement.
6.55 6.50
6.48 6:68 6.70 6.39 7.04 6.32
M90 0000
- - - - -
12.73 12.30 12.08 12:60
12.62 11.88 13.49 11.71
00T 0000 - -
- - -
000000
1301
17E1 31B 48.A3
28.68 6.22 2.00
6.19 7.92
»
(00 5 26 AO 45
110.91E1 112.6EE1 136.55B1 15B.59B1 109.75E 122.97B 128.62B 119.63A
ME
9.58 10.33 2.28 6.1E 7.92
119.10E1 150.67E1 554.00B1 208.60A1 116.45E 165.36B 173.23B 200.34A
*
E
9.66 11.04 3.24 6.53 11.S
220.34 223.24 264.24 291:15 245.30
233.E7
243.64 276.59
00
- - - - -
groundnut
cassava
Treatments of
Effect
EV(X)
Effects
EV(X)
cake
flour
L00 L00po P1 P2 °§ Eo E1 E2 E3 00
Eont'd
Table4.Energyintaka dlivweightgainbyWestAfricadw fgoa sfcomb natio sf
gradedlevelsofoundnutcak(P)ancassavaflourEc centratesupplement.
6.74 6.72 6.74 6.58 6.15 5.95 6.42 7.05 7.53 7.E
6.53 7.01
H00T 0000
12.74 12.69 12.73 12.32 11.28 10.78 11.E4 13.53 11.78 13.58
12.20 13.40
00T 0000
Sde. 26de 38bed
30cde 15ef 22ef 00be
0000
(00
11f 7f 10f
-4 -E
»
E8.31fg
81.46g
119.74def 139.Ebed 105.61ef
120.75def
136.76cd 128.77de 104.87f
115.43def
131.45d
162.71ab
HE
»
159.72cde 162.65cde 154.98cde
131.50fg
108.11g
556.39be
141.10
554.33c
173.00cd 111.10df 177.24c 219.62a
E
219.95 204.00 261.60 293.89 208.53 219.46
S8.12
249.76 204.88 232.36 240.21 297.12
7
Eombinations
Treatments
EoP
EoP1 EoP2 EoP3
E1Po
E1P E1P2 E1P3
E2Po
E2P1 E2P E2P3
ro o
Eont'd
Table4.Energyintakea dlivweightgainby00estAfricadw rfgoa sf dcombin tionf
gradedlevelsofg oundnutc k(P)ancassavaflourEc centratesupplement.
S■—w9
Treatments00EMEDL00TW (000 00
6.49 6.49 6.22 6.0E - - -
12.13 12.13 11.45 11.13 - - -
00cde
37cd 52ab
62a 4.26 28.68 12.45
134.83d 133.11d
159.18abe 171.39a
7.E 9.58 20.66
552.34c 176.91c
218.42ab
235.69a
9.60 9.66 28.01
2E.98
236.48
298.13
323.48
- - -
E3Po
E3P1 E3P2 E3P
00 EV(%) L00
N.B:Figuresinacol mnwiththesalet rscriptanot
significantlyd fferen(P>0.05).
*00cal/day/W0-75kg
00E=grossenergyELW00daillivewei htg in
EE=digestibleenergyAWTav agw ight
ME=metabolisableenergyWTbolicw ight
OJ
REFERENCES
Adegbola, T. 1974. Digestion and utilisation of protein in West
African Dwarf sheep. Ph.D. thesis, Dept. of Animal
Science, University of Ibadan, Ibadan, Nigeria.
Akinsoyinu, A.O. 1974. Studies on protein and energy
utilisation by the West African Dwarf goat. Ph.D.
thesis, Dept. of Animal Science, University of Ibadan,
Ibadan, Nigeria.
AOAC (Association of Official Analytical Chemists). 1970.
Official methods of analysis. 11th edition. AOAC,
Washington, D.C., USA.
Awah, A. A. 1982. Effect of milk and concentrate feeding on
nutrient utilisation and tissue development of West
African Dwarf (Fouta Djallon) kids under humid tropical
environments. Ph.D. thesis, Dept. of Animal Science,
University of Ibadan, Ibadan, Nigeria.
Blaxter, K.L. and Wainman, F.W. 1964. The utilisation of the
energy of different rations by sheep and cattle for
maintenance and for fattening. J. Agric. Sci., Camb.
63: 113-128.
Blaxter, K.L. and Clapperton, J.L. 1965. Prediction of the
amount of methane produced by ruminants. British J.
Nutr. 19: 511-522.
Crabtree, J.R. and Williams, G.L. 1971. The voluntary intake
and utilisation of roughage concentrate diets by sheep.
I. concentrate supplement for hay and straw. Anim.
Prod. 13: 71-82.
Elliot, R.C. and Topps, J.H. 1963. Voluntary intake of low
protein diets by sheep. Anim. Prod. 5: 269-276.
322
Goering, H.K. and Van Soest P.J. 1970. Forage fibre analyses
(apparatus, reagents, procedures and some application).
Agricultural Handbook No. 379, USDA, Agricultural
Research Service, Washington, D.C.
Mason, V.C. 1969. Some observations on the distribution and
origin of nitrogen in sheep faeces. J. Agric. Sci.,
Camb. 73: 110-111.
Steel, R.G.D. and Torrie, J.H. 1960. Principles and procedures
of statistics. McGraw-Hill Book Company Inc., New York,
USA.
323
COMPARISON OF FEED UTILIZATION BY WEST AFRICAN DWARF SHEEP FED
SODIUM HYDROXIDE TREATED SOYABEAN PODS SUPPLEMENTED WITH SOYABEAN
FLOUR OR FRESH NAPIER GRASS FED ALONE OR WITH SOYABEAN FLOUR
R.M. Njwe and Godwe
Department of Animal Science
Dschang University Centre
Dschang, Cameroon
ABSTRACT
A comparison of feed utilization and liveweight gain was
carried out with adult West African Dwarf sheep fed sodium
hydroxide (NaOH) treated dry soyabean pods supplemented with
soyabean flour; or fresh Napier grass fed alone or supplemented
with soyabean flour.
There were no significant differences in the intake of
dry-matter and proximate feed constituents between sheep fed
alkal i -treated soyabean pods supplemented with soyabean flour
and those fed fresh Napier grass plus soyabean flour. Sheep
fed only Napier grass consumed significantly more crude fibre
but less dry-matter, crude protein, ether extract and nitrogen-
free extract than those on the other diets.
The digestibility of dry matter, organic matter, crude
fibre and nitrogen-free extract were similar for sheep fed
solely on Napier grass and those fed on fresh Napier grass plus
soyabean flour. The digestibility of crude protein and ether
extract by sheep fed only on Napier grass was significantly
lower than the other treatments. All experimental animals had
positive nitrogen balance.
Liveweight gain was similar for sheep fed fresh Napier
grass supplemented with soyabean flour (77 g/day) and those
provided NaOH- treated soyabean pods plus soyabean flour (79
g/day). Animals fed solely on Napier grass gained 41 g/day
which was significantly lower than the other treatments.
324
INTRODUCTION
The commencement of the soyabean project in the Western
Province of Cameroon in 1981 has resulted in increased
production of the crop. The primary aim of the project was to
provide the human population adequate plant protein and cooking
oil. However, the livestock sector has a lot to benefit from
the project, especially as the cake resulting from oil
extraction will be used in livestock rations. Crop residues
such as leaves and pods can also be used to feed livestock. The
use of these by-products in feeding livestock in the Western
Province is of particular significance since the increasing
density of the human population is rapidly taking over pasture
land for cultivation of food crops. Semi- intensive or intensive
small ruminant production is the best alternative available to
farmers if this activity has to continue.
The objective of the present study was to compare feed
utilization by local sheep fed Napier only, Napier grass plus
whole undefatted soyabean flour and NaOH treated dry soyabean
pods plus whole undefatted soyabean flour.
MATERIALS AND METHODS
Nine adult West African dwarf sheep were selected from the
flock of experimental sheep at the Dschang University Centre
farm for this study. The flock of sheep had been on adequate
plane of nutrition and received adequate health care. The
animals were randomly divided into three groups - T1, T2, and
T3 in a completely randomised design with group mean weights of
17.73+ 2.25, 18.10+1.99 and 18.16+1.92 kg, respectively. The
experimental treatments (diets) were as follows:-
T, - Control (fresh Pennisetum purpureum or Napier grass
only) .
T- - Napier grass plus 250 g ground undefatted
soyabean/ animal /day.
T, - Sodium hydroxide- treated dry soyabean pods plus 250 g
ground undefatted soyabean /animal/day.
325
Dry soyabean pods were treated with 4% NaOH solution by
sprinkling the solution (800 ml/kg) on the pods using a water
sprinkling can and manually mixing them to uniform wetness. The
mixture was then covered with polyethylene sheets and jute bags
for 24 hours after which the pods were dried in the sun and
packed in jute bags until required for feeding animals.
Animals in each treatment were group-fed during the first
5 weeks of the experiment. During the last two weeks they were
transferred into individual metabolic cages to facilitate
digestibility studies. Freshly cut Napier grass and NaOH-
treated soyabean pods were fed to animals twice daily at 9:00
and 16:00 hours, while ground undefatted soyabean was fed once
daily at 9:00 hours in a separate feeding trough. The chemical
composition of Napier grass, dry soyabean pods and undefatted
soyabean are indicated in Table 1. Water and salt licks were
provided ad libitum in each cage. The weights of feed fed
residues were daily recorded and their dry-matter contents were
determined.
The adaptation period in cages was one week. This was
followed by a 7-day collection period during which faeces and
urine of each animal were collected and measured every 24
hours. Ten percent mercuric chloride solution was used to
prevent the loss of ammonia in urine during collection and
storage. Urine samples were stored in corked bottles in a deep
freezer while daily faecal samples were dried in a laboratory
oven for 48 hours at 60°C and stored in polyethelene bags until
the time of analysis.
326
Table 1. Chemical composition of the experimental diets (% dry
matter).
As fed On organic-matter basis (%)
Dry- Organic Crude Crude Ether Nitrogen
matter Ash matter protein fiber extract free
extract
Pennisetum purpureum
(Napier grass) 16.11 17.07 88.94 16.97 33.83 3.81 34.33
NaOH-treated
dry soyabean pods 92.02 12.33 87.67 17.47 30.97 3.21 36.02
Undefatted
soyabean flour 90.72 5.62 94.38 37.62 10.03 23.15 23.58
Feed and faecal samples were analysed for dry-matter and
other feed constituents according to A.O.A.C. methods (1975).
Urine nitrogen was analysed using the micro-KJeldahl method.
Statistical analysis of experimental data was carried out
according to the methods of Steel and Torrie (1960) and
significant differences between treatments were determined
using Duncan's Multiple Range Test (1958).
RESULTS
Table 2 shows the intake of dry matter and nutrients by West
African Dwarf sheep. Dry-matter intake was 66.98, 74.82 and
75.31 g/day/W ' kg for sheep fed solely fresh Napier grass
(T.), Napier grass plus undefatted soyabean flour (T~) and
NaOH-treated dry soyabean pods plus undefatted soyabean flour
(T,), respectively. Sheep fed only on Napier grass consumed
significantly (P<0.05) less dry-matter than the other two
treatments. However, the values for animals fed undefatted
soyabean flour supplement were similar.
327
Table 2. Dry-matter and nutrients intake by West African Dwarf sheep
on the three experimental diets.
T1 T2 T3
Group means
Napier grass
with no
supplement
Napier grass
+ undefatted
soyabean meal
NaOH treated
soyabean pods
+ undefatted
soyabean meal
,0. 75kg
Dry matter
g/day/W
Organic matter
,, _ ,0.75kg
g/day/W
Crude protein
g/day/W1
Crude fibre
g/day/W
Ether extracts
,0.75kg
,0.75kg
g/day/W
,0.75kg
Nitrogen-free extracts
g/day/W0-75"9
Initial liveweight (kg)
Final liveweight (kg)
Average weight (kg)
Metabolic weight(W°"75kg) 9.01+0.88
Liveweight gain (g/day) 41+7b
590.20+9.80
68. 98+5. 06b
524.86+8.72
59. 57+1 01 5b
100.15+1.66
11.36+0.86b
199.66+3.29
22.66+1 .71a
22.48+0.37
2. 55+0. 19b
202.55+3.36
22.98+1 .74b
17.77+5.40
19.93+5.18
18.85+2.49
699.53+8.01
74. 82+5. 09a
634.65+7.14
67.83+4. 60a
165.50+1.38
7. 70+ 1.22a
182.67+2.71
19.55+1.39ab
70.50+0.31
7. 54+0. 53a
215.72+2.75
23.95+1.70ab
18.10+4.00
22.17+3.82
20.13+1.84
9.48+0.68
77+5a
701.38+4.64
75.31+6.44a
630.12+4.07
67. 65+5. 77a
168.34+0.81
18.06+1. 50a
169.72+1.39
18.23+1 .59b
67.73+0.13
7. 26+0.59a
224.42+1 .67
24. 70+2. 08a
18.16+4.07
22.33+4.25
20.16+1.92
9.49+0.69
79+3a
N.B. Values in a row with same letter script are not significantly
different (P>0.05).
328
There was a direct relationship between dry-matter and
crude protein intakes. Crude-protein intake by sheep fed only
Napier grass (11.36 g/day/U * ) was significantly (P<0.05)
lower than in sheep fed the grass plus undefatted soyabean
flour (17.70g/day/W * ) and those fed NaOH-treated soyabean
pods plus undefatted soyabean flour (18.06 g/day/W ' kg).
The trends of organic-matter and ether-extract intakes
were similar to those of crude protein. Crude-fibre intake by
sheep on the control treatment (T,.) was significantly (P<0.05)
higher than those on T3 (22.66 and 18.25 g/day/W0"75 kg
respectively) but similar to those on T2 (19.55 g/day/W * kg).
The same trend was observed for intake of nitrogen-free
extract.
Table 3 shows the digestibility of dry matter and
nutrients. The digestibilities of dry matter at 68.82% and
96.67% were similar for sheep fed Napier grass alone and those
on Napier grass plus undefatted soyabean flour. Dry-matter
digestibility by sheep fed on Napier plus undefatted soyabean
flour was significantly (P<0.05) higher than in two NaOH-
treated dry soyabean pods plus undefatted soyabean flour
(66.72%) which was in turn similar to the control treatment.
The highest value of crude-protein digestibility was
recorded with animals fed Napier grass and undefatted soyabean
flour (83.04%) which was not statistically significant to
79.70% obtained with sheep fed soyabean pods plus undefatted
soyabean flour. The value for sheep on the control treatment T1
(74.88%) was significantly (P<0.05) lower than in T2 but not
statistically signif icant(P>0.05) to T3.
329
Table 3. Percent digestibility of dry matter and other
nutrients by West African Dwarf Sheep (%) on the
tested diets.
Treatments
Group means % T1 T2 T3
Dry matter 68..89+4.,23ab 69. 67+ 1.06a 66..70+2,.36b
Organic matter 72..53+4..67ab 73. 34+1. 22a 67,.77+2,.15b
Crude protein 74,.88+2,.72b 83. 04+0. 43a 79,.70+1,.09ab
Crude fibre 75.. 29+3 . 82a 65. 36+3. 66b 62,.13+1,,58b
Ether extract 59..18+5..12b 83. 89+2. 66a 83..85+2,.73a
Nitrogen-free extract 70..13+4..78a 69.18+1.98ab 60.,89+2,.51b
N.B. Values in a row with same letter script are not
significantly different (P>0.05).
Crude-fibre digestibility by sheep fed on T1 (95.29%) was
significantly (P<0.05) higher than those on T3 (62.13%) and on
T2 (65.36%).
On the other hand, ether-extract digestibility by sheep on
T1 (58.18%) was significantly (P<0.05) low when compared to T2
and T3 treatments which had similar values (83.89 and 83.85%).
The digestibility of nitrogen-free extract by sheep on T1 and
T2 (70.13 and 69.18% respectively) were similar. However, T1
was significantly (P<0.05) higher than T3 (60.89%).
Utilization of dietary nitrogen by West African Dwarf
sheep is indicated in Table 4. Nitrogen intake and digested
nitrogen by animals on T1 were significantly (P<0.05) lower
than the other two treatments which were of similar values.
This was also the case with nitrogen balance. None of the
experimental animals had negative nitrogen balance.
Average daily weight gain by sheep is indicated in Table
2. Live weight gain by animals on T1 (41 g/day) was
significantly (P<0.05) lower than those on T2 (77 g/day) or
those on T3 (79 g/day). Treatments fed undefatted soyabean
flour supplement had similar values.
330
Table 4. Nitrogen balance of West African Dwarf Sheep on the
experimental diets.
Treatments
Group means % T1 T2 T3
Nitrogen intake (g/day) 16. 03+0. 27b 26. 48+0. 22a 26.93+0. 13a
Faecal nitrogen (g/day) 4. 04+0. 47b 4.47+0. 104b 5. 46+0. 35a
Digested nitrogen (g/day) 11. 98+0. 33b 22. 01+0. 26a 21. 47+0. 29a
Urinary nitrogen (g/day) 10. 34+0. 56a 9. 83+0. 68a 7. 89+0. 25b
Nitrogen balance (g/day) 1.64+0. 61b 12. 18+0. 42a 13. 58+0. 41a
N.B. Values in a row with same letter script are not
significantly different (P>0.05).
DISCUSSION
Dry-matter intake by West African Dwarf sheep ranged from 66.98
to 75.98 g/day/W " kg. These values are higher than those
reported by Namadiga (1983). The increase of dry-matter intake
with addition of protein supplement can be attributed to the
protein stimulating effect on microbial digestive activity of
cellulose. When nitrogenous compounds are deficient in a diet
or when only small amounts are present, the growth of rumen
microbes in the rumen is greatly inhibited and may lead to
inefficient feed utilization.
The improvement of the digestibility of dry-matter, crude
protein and ether extract in the present study agrees with
those of Briggs and Heller (1942) from feeding large amounts of
cottonseed meal in fattening lamb rations.
The decrease in crude fibre digestibility observed during
this investigation may be attributed to a substitution effect
of readily digestible undefatted soyabean flour.
The fact that all experimental animals were in positive
nitrogen balance is a reflection of adequate dietary protein
331
even when Napier grass was the only diet at T1. Animals on
fresh Napier grass gained on the average 41 g per day during
the experimental period. The high nutritive value of Napier
grass at the beginning of the wet season (16.97% crude protein)
can be responsible for this performance.
Soyabean pods treated with NaOH and undefatted soyabean
flour to sheep promoted weight gains similar to that by animals
fed on Napier grass and undefatted soyabean flour. Kpounoho
(1986) fed untreated dry soyabean pods with cottonseed meal to
local dwarf sheep and observed slight weight losses or at the
best body weight was maintained. The utilization on NaOH-
treated soyabean pods in the present study appears to stimulate
higher dry-matter intake and therefore some liveweight gain (79
g/day). Improvement of straw uti lization by NaOH treatment has
also been indicated by Kategile et al (1979). The optimal
treatment rate by NaOH has been reported to be 4% (Klopf enstei n
et al, 1972 and Hasimoglu et al, 1969).
It may be concluded that supplementation of Napier grass
with undefatted soyabean flour feed intake gave adequate levels
of improved digestibility and weight gain compared to the
Napier grass fed alone. It is possible to maintain sheep on dry
soyabean pods treated with NaOH solution and undefatted
soyabean flour particularly during the dry season when grass of
good nutritive value is scarce.
REFERENCES
A.O.A.C. (Association of Official Analytical Chemists). 1970.
Official methods of analysis. AOAC, Washington, D.C.,
USA.
Briggs, H.M. and Heller, V.G. 1942. The effect of adding large
amounts of cottonseed meal to a lamb fattening ration. J.
Anim. Sci. 1:277.
Duncan, D.B. 1958. Multiple Range and Multiple F. test.
Biometrics (1): 1-42.
Hasimoglu, S.; Klopf enstein, T.J. and Doane, T.H. 1969.
Nitrogen source with sodium hydroxide treated wheat
straw. J. Anim. Sci. 29:160 (Abstract).
332
Kategile, J. A. and Frederikson, J.H. 1979. Effect of level of
NaOH-treatment and volume of solution on the nutritive
value of maize cobs. Anim. Feed Sci. Technol. 4:1-15.
Klopfenstein, T.J.; Krause, V.E.; Jones, M.J. and Walter, W.
1972. Chemical treatment of low quality roughages. J.
Anim. Sci. 35:418.
Kpounoho, I. 1986. Utilization and nutritive value of soyabean
husk with or with no cotton seed cake by sheep. Final
year memoir. Dept. of Animal Science, ENSA, Dschang
University Centre, Cameroon.
Namadiga, P. 1983. The protein requirements of young
blackbelly sheep. Final year memoir. Dept. of Animal
Science, Dschang University Centre, Cameroon.
Steel, R.G.D. and Torrie, J.H. 1960. Principles and procedures
of statistics. McGraw-Hill Book Company Inc., New York,
USA.
333
PROCESSED AND UNPROCESSED SORGHUM STOVER IN
BEEF FINISHING RATIONS
T.A. Mohammed, A.E. El-Tayeb, A.F. Mustafa and H.M. Khogali
Department of Animal Nutrition, Institute of
Animal Production, University of Khartoum
P.O. Box 32, Khartoum North, Sudan.
ABSTRACT
Two eight-week feeding trials using entire male cattle were
conducted to evaluate the effects of incorporating processed
and unprocessed sorghum stover in traditional concentrate diets
used for finishing cattle in the Sudan. In the first trial
milled sorghum stover was used to replace the concentrate mix
at the rate of 0, 25, 35 and 45% (W/W). In the second trial the
experimental animals were offered unprocessed sorghum stover ad
I ib in addition to the concentrate mix which was offered at
100, 75, 65 and 55% of the ad lib level of intake.
The first trial showed that incorporation of milled
sorghum stover in the diets had no effect on the performance of
the animals.
Animals in all treatments consumed an amount of feed
equivalent to 3.0% of their body weight and gained at an
average rate of 1.40 kg/d.
The results of the second trial showed that the intake of
unprocessed sorghum stover increased as the amount of
concentrate offered was decreased. The rate of gain of the
experimental animals was not affected by the treatment and was
about 1.0 kg/d. However, the efficiency of feed utilisation was
higher when the animals were offered the concentrate mix ad I ib
than when the concentrate mix was limited.
INTRODUCTION
The Sudan ranks among the top African countries owning
livestock. Statistics indicate that there are about 21 million
334
tropical livestock units (TLU) composed respectively of 15.0,
16.0, 12.0 and 2.3 million head of cattle, sheep, goats and
camels. Most of those livestock are kept under extensive
management systems and are fed exclusively on rangeland grazing
resources.
Livestock commercial offtake rates were low prior to 1973
and have been increasing since. Today it is estimated that 2.61
million TLU are transported annually to feedlots in the major
urban centres for finishing before slaughter or export.
Approximately 60-70% of the animals finished are cattle.
Cattle are finished on ad I ib feeding of concentrate
rations composed of equal parts of ground sorghum grain and
cottonseed cake for a period of 8 weeks. The availability of
the two ingredients and the simplicity of the formulation are
the reasons behind the popularity of this feeding regime.
However, recent increased local and export demands for sorghum
grain and cottonseed cake elevated prices to levels that
limited the expansion of the growing feedlot operations in the
country.
Arable farming in the Sudan has grown considerably since
independence in 1956, and areas under cultivation today are
estimated at 15-20 million feddan producing 7-9 million tons of
crop residues, of which 60-70% is sorghum stover. The bulk of
the sorghum stover produced is of little use to cultivators and
is normally disposed of by means other than feeding to animals.
A research project was initiated in the Sudan by IDRC with
the intention of maximising the use of agro- industrial by
products in livestock feeds. Results of on-farm trials
conducted during the earlier phases of the project (Mohammed
Salih, 1986) suggested the possibility of incorporating
relatively high levels of processed and unprocessed sorghum
stover in beef finishing rations.
The objective of the on-station trials reported in this
paper was to investigate the effects of partial replacement of
the traditional concentrate ration with processed and
335
unprocessed sorghum stover. The trials were designed in
response to the reactions of feedlot operators involved in on-
farm trials during earlier stages of the project.
MATERIALS AND METHODS
Twenty-four feeder bulls, 5-6 years old and of the western
Sudan type were used in each of the trials for a finishing
period of 8 weeks. The bulls used in each of the trials were
stratified according to body weight into 8 groups of 3 bulls
each. In each trial the groups were allotted randomly to four
treatments (2 groups/treatment).
In trial 1, chopped and milled sorghum stover was
incorporated into the traditional basal concentrate mixture at
rates of 0, 25, 35 and 45%, and offered ad lib. Ingredients and
chemical composition of the diets are shown in Table 1.
Table 1. Ingredient and chemical composition of diets used in
trial 1.
Level of mi I led sorghum stover (%)
Item 0 25 35 45
Ingredient composition (%)
Ground sorghum grain 49.5 37.0 32.0 27.0
Cottonseed cake 49.5 37.0 32.0 27.0
Milled sorghum stover - 25.0 35.0 45.0
Salt 1.0 1.0 1.0 1.0
Chemical composition (%DM)
DM 95.5 94.4 95.4 95.5
OM 91.2 88.4 88.6 88.3
CP 22.8 18.2 16.8 15.4
ADF 25.0 28.4 32.5 34.1
EE 4.2 3.4 3.1 3.9
Ash 4.3 6.0 6.8 7.2
336
In trial 2, unprocessed sorghum stover was offered ad I ib
to all animal groups together with the traditional basal
concentrate mixture at 100, 75, 65 and 55% of the ad I i b
intake. The ad lib intake of the traditional concentrate
mixture was adjusted weekly. The unprocessed sorghum stover and
the traditional concentrate mixture were offered simultaneously
in two adjacent mangers once in the morning and refusals were
collected the next morning. Chemical composition of the
traditional concentrate mixture and sorghum stover used in
trial 2 are presented in Table 2. Feeds were analysed using
standard methods (AOAC, 1980).
Intake of the complete diets (trial 1), concentrate
mixture and unprocessed stover (trial 2) were recorded daily
and animals were weighed weekly. At the end of each week feed
conversion ratios were computed.
Table 2. Chemical composition of traditional concentrate
1 2
mixture and sorghum stover used in trial 2.
Traditional concentrate Sorghum
Item mixture stover
95.7
3.5
35.5
11.5
Price LS/ton 717.8 200.0
1. The traditional concentrate mixture is composed of 49.5%
sorghum grain, 49.5% cottonseed cake and 1.0% salt.
2. Cost of milling sorghum was LS 75/ton.
Data were analysed using analysis of variance (Steel and
Torrie, 1980). When differences were significant (P<0.05)
Duncan's multiple range test was employed to detect differences
among treatment means.
DM 95.5
CP 22.8
ADF 25.0
Lignin 6.2
337
RESULTS
Performance parameters of bulls used in trial 1 are presented
in Table 3; treatments had no effect on dry-matter intake, rate
of body weight gain or food utilisation. Irrespective of the
treatment daily feed consumption and rate of body weight gain
average 131 g/kg metabolic body weight and 1.4 kg,
respectively. Average feed conversion (kg feed/kg gain) was
7.7.
Performance parameters of bulls used in trial 2 are
presented in Table 4. They show that treatment significantly
(P<0.05) affected dry-matter intake and feed utilisation but
had no effects on rate of body weight gain. It was observed
that total dry-matter intake progressively increased (P<0.05)
as the amount of concentrate offered was decreased. Feed
consumption/kg metabolic body weight increased from 117 g for
the ad lib and 75% ad lib treatments to 126 g for the 65 and
55% ad I ib treatments. The increase in the total dry matter was
a result of increased (P<0.05) consumption of unprocessed
sorghum stover as the amount of concentrate offered was
reduced. The consumption of unprocessed sorghum stover
increased from 1.0 kg when concentrate was offered ad I ib to
3.5, 5.1 and 6.2 kg when the concentrate was offered at 75, 65
and 55% ad I ib respectively. A decrease in concentrate offered
by 1 kg is substituted for by consumption of approximately 1.5
kg of unprocessed sorghum stover. The feed conversion ratio
was significantly (P<0.05) lower for bulls offered the
concentrate ad I ib than bulls offered other treatment.
338
Table 3. Performance of bulls used in trial 1.
364.0 365.0 363.4 365.2 4.7
443.0 442.3 442.6 445.0 6.2
8.0 8.0 8.0 8.0 -
1.41 1.38 1.41 1.43 0.4
10.44
125. 3a
11.04
132. 5bC
10.70
128.8ab
11.38
136. 6C
0.4
1.7
2.9 3.0 2.9 3.1 0.04
7.4 8.0 7.6 7.9 0.11
5.31 4.86 4.28 4.10 -
Level of milled sorghum stover(%) SE
Parameter 0 25 35 45
Initial body weight (kg)
Final body weight (kg)
Finishing period (weeks)
Dai ly gain (kg)
Daily feed intake (kg)
Daily feed intake (g/kg ,
Feed intake (% body wt)
Feed conversion
(kg feed/kg gain)
Cost of feed (LS/kg gain)
Values with the same letter script are not significantly
different (P>0.05).
DISCUSSION
El Hag and Kurdi (1986) concluded that milled sorghum stover
could be included in beef finishing rations to levels not
exceeding 30% (W/W). In this study milled sorghum stover was
incorporated in concentrate finishing rations to levels as high
as 45% (W/W) without negative effects on basic performance
parameters. This is in agreement with Lamming et al (1966) who
used milled barley straw as a substitute for maize in beef
finishing rations. It was concluded that the traditional system
of feeding (concentrate mix ad I ib) is wasteful; since the
replacement of the concentrate mixture with milled sorghum
stover to levels as high as 45% had no effect on feed
consumption, rates of body weight gain and feed utilisation.
Under the prevailing conditions in the Sudan the milling
of sorghum stover is inconvenient to some users and definitely
increases the costs of production. Nevertheless it was thought
339
that the feasibility of using high levels of milled sorghum
stover as a substitute for the concentrate mix in traditional
beef finishing rations would be more tempting to feedlot
operators.
Table 4. Performance of bulls used in trial 2.
Traditional concentrate mixture SE
offered (% ad lib)
Parameter 100 75 65 55
Initial body weight (kg)
Final body weight (kg)
Finishing period (weeks)
Dai ly gain (kg)
Daily DM intake (kg)
Daily sorghum stover
intake (kg)
Daily concentrate intake (kg)
Substation rate (cone.
roughage)
Feed intake (% body wt)
Daily feed intake (g/kg * )
Feed conversion (kg feed/kg
gain)
Cost of feed (LS/kg gain)
Values with the same letter script are not significantly
different (P>0.05).
Studies on the use of unprocessed sorghum stover in beef
cattle rations are scarce. Lofgreen et al (1981) demonstrated
that calves given concentrate diets consumed significantly less
feed than those given limited concentrate and roughage free
choice. In this study (trial 2) the feeding of limited amounts
of all concentrate diet stimulated bulls to consume more of the
unprocessed sorghum stover which resulted in higher total dry-
matter intake.
313.8 313.2 313.2 313.8 5.1
375.4 363.6 374.8 375.4 3.0
8.0 8.0 8.0 8.0 -
1.1 0.9 1.1 1.1 0.1
9.5 9.7 10.5 10.5 0.5
1.0a 3.5b 5.1c 6.2d
0.4
8.5 6.2 5.4 4.3 0.3
- 1.5 1.6 1.5 -
2.7 2.7 2.9 2.9 -
117.0 119.0 125.0 128.0 -
8.6a 10. 8b 9.5C 9.5C
0.3
5.73 5.73 4.43 3.92 -
340
Montgomery and Baumgardt (1965) observed that ruminants
adjust their voluntary feed intake to their physiological
demands for energy. In this study it was noted that bulls
consumed more of the unprocessed sorghum stover than the
replacement increment from the concentrate.
Average daily gains were the same for all treatment groups
used in trial 2. This confirms the earlier conclusion that the
systems based on the exclusive feeding of an all-concentrate
diet is wasteful. Bulls fed the limited concentrated diets not
only gained at similar rates as those offered the concentrate
diet ad lib, but had the additional advantage of consuming
significantly (P<0.05) greater amounts of unprocessed sorghum
stover.
Lister et al (1968) reported that feed per unit gain was
significantly (P<0.05) greater for steers fed roughage only
compared with those fed roughage plus a high concentrate diet.
In trial 2 the feed conversion ratio was significantly (P<0.05)
better for bulls fed the concentrate diet ad I ib than for those
fed limited concentrate amounts together with unprocessed
sorghum stover. However, it must be borne in mind that the
inexpensive unprocessed sorghum stover represented a
significant proportion of the feed consumed in the latter
diets. It is apparent that these diets would be adopted more by
feedlot operators looking for convenience and reduced
production costs.
It was concluded that the traditional system of free
choice concentrate feeding is wasteful. Concentrates could be
replaced by as much as 45% with milled or unprocessed sorghum
stover without undesirable effects on the performance of
finishing bulls.
REFERENCES
A.O.A.C. (Association of Official Analytical Chemists). 1980.
Official methods of analysis. 13th ed. AOAC, Washington,
D.C.
341
El Hag, M.G. and Kurdi, O.I. 1986. Prospects for efficient
utilisation of agro- industrial by-products and crop
residues for ruminant feeding in the Sudan, with
emphasis on quantification, nutritional composition,
constraints and research results. In: T.R. Preston and
M.Y. Nuwanyakpa (eds), Towards optimal feeding of
agricultural by-products to livestock in Africa.
Proceedings of a workshop held at the University of
Alexandria, Egypt, October 1985. ILCA, Addis Ababa,
Ethiopia.
Lamming, G.E.; Swan, H. and Clark, R.T. 1966. Substitution of
maize by milled barley straw in beef fattening diets and
its effect on performance and carcass quality. Anim.
Prod. 2: 303.
Lister, E.E.; Heaney, D.P. and Pigden, W.J. 1968. Performance
of Holstein-Friesian steers fed on all-concentrate diet
diluted with ground hay. J. Dairy Sci. 51: 1946.
Lofgreen, G.P.; El-Tayeb, A.E. and Kliesling, H.E. 1981.
Millet and alfalfa hays alone and in combination with
high energy diet for receiving stressed calves. J. Anim.
Sci. 52: 959.
Mohammed Sal ih, G.M. 1986. Effect of sorghum straw feeding on
feedlot performance of cattle. M.V.Sc. thesis, University
of Khartoum, Sudan.
Montgomery, M.J. and Baumgardt, B.R. 1965. Regulation of feed
intake in ruminants. 1. Pelleted rations varying in
energy concentration. J. Dairy Sci. 48: 569.
Steel, R.G. and Torrie, J.H. 1980. Principles and procedures
of statistics. 2nd ed. McGraw-Hill Book Co., New York.
342
HYDRATION AS A MEANS OF IMPROVING UTILIZATION
OF MAIZE STOVER FED TO STEERS
L. R. Ndlovu and Z. Manyame
Department of Animal Science
University of Zimbabwe
P.O. Box MP 167
Mt Pleasant
Harare, Zimbabwe
ABSTRACT
Maize stover chopped to particles 4-6 cm in length was fed to
steers either soaked in water (1 kg stover/1.5 I) for 24 hours
or unsoaked. For each main roughage, four protein supplements
were provided viz. control, urea, soyabean meal or blood-
treated soyabean meal plus urea.
Soaking increased (P<0.05) intake of dry matter (DM) (4.8
vs 3.7 kg/d) but apparent DM digestibility and rumen digestion
kinetics were not affected by soaking (P>0.05). Protein
supplementation increased (P<0.05) DM intake (4.9 vs 4.4 kg and
3.8 vs 3.4 kg) for hydrated and unhydrated stover,
respectively. Apparent DM digestibility and nylon bag
degradabi I i ty were, however, not affected by protein
supplementation (P>0.05).
It was concluded that soaking per se has a potential to
overcome constraints to intake of maize stover, particularly in
situations where protein sources are scarce or expensive.
INTRODUCTION
Most of the ruminant livestock in Zimbabwe depend on maize
stover as the main energy source during the dry season.
Voluntary feed intake of this roughage is usually low mainly
because the stover is harvested at a very mature stage and
343
allowed to dry extensively before being fed to the animals.
Maturity increases cell wall constituent fractions (for
instance) and decreases protein content; both factors are
inimical to digestion of a forage. Dryness increases time
spent chewing per bolus (Welch, 1982) and thus reduces total
intake.
Hydration has a potential to overcome these constraints.
Soaking causes swelling of cell wall structures and thus should
make them more accessible to cellulolytic microbes. In
addition it reduces the dustiness and dryness of the feed.
However, results from experiments where rice straw was soaked
or wetted have been unequivocal as to the effects of this
treatment (Doyle et al, 1986).
The main objective of this experiment was to investigate
the effect of hydration on the utilization of maize stover by
steers. The second objective was to investigate if there were
any interactions between protein (source) and soaking.
MATERIALS AND METHODS
Animals and diets
Eight Hereford-Cross steers, two years old and fitted with
permanent rumen cannulae were randomly assigned to two 4x4
Latin squares. Each square represented hydration or lack of it
of the maize stover, the basal diet. Hydration was effected by
soaking stover in water at the rate of 1 kg stover/1.5 litres
of water for 24 hours.
Unsoaked stover was wetted with an equal amount of water
at feeding. The chemical composition of the stover used was:
dry-matter (g/kg) 890; neutral -detergent fibre (g/kg DM) 930;
organic matter (g/kg DM) 978.9; crude protein (g/kg DM) 22.9.
Three protein supplements plus a control (no protein) were
the treatments imposed in each square. The protein supplements
were:
344
(i) urea (30 g/kg of stover)
(ii) soyabean meal (300 g/d), and
(Hi) urea (30 g/kg of stover) plus blood- treated soyabean
meal (250 g/d).
Blood- treatment was effected by coating soyabean meal with
blood at a rate of 1 litre blood/2 kg soyabean meal and baking
the mixture at 88 C for 36 h in an oven. Urea was dissolved in
water before adding to stover and sprinkled at the time of
feeding.
The animals were held in individual stanchions and fed
twice daily (0800 and 1600 h); orts were weighed and sampled in
the morning. Water and a commercial salt lick containing trace
minerals were available all the time. Rubber mats were used
for bedding to facilitate cleaning and collection of faecal
samples.
Measurements
The periods were 33 days long and the schedule of activities is
shown in Table 1. During measurement of ad libitum intake, the
animals were offered 20% more stover than their previous day's
intake. The total collection method was used to measure
digestibility while rumen digestion parameters were measured
using the nylon bag technique (Orskov and McDonald, 1979) with
up to 96 h incubation in the rumen.
Table 1. Schedule of activities in each period.
Day Activity
1-10 Adjust animals to diet
11-20 Measure ad I i bit um intake
21 Dose with chromium-mordanted fibre
21-27 Total faecal collection with subsamples for rates
of passage measurements
28-32 Nylon bag incubation and removal
33 Empty rumens, weigh digesta sample and return to animal
345
Laboratory and statistical analysis
Dry matter (DM) of stover, orts and faeces was determined by
drying at 100 C overnight.
Data from the nylon bag technique were analysed using the
- ct
equation p = a + b (1 - e ) where p is total amount that has
disappeared from the bag at time ti, a is the amount lost
through washing, b the amount that in time will degrade and c
the rate at which the b fraction degrades.
Statistical analysis appropriate for a double Latin square
that accounts for the effects of square, animals, periods and
protein supplements (Snedecor and Cochran, 1967) was used.
Treatment means were compared using t-tests.
RESULTS
Intake
Hydration increased intake (P<0.05) by 23% while protein
supplementation increased (P<0.05) intake by 11% (Table 2).
There was no interaction (P>0.05) between hydration and protein
supplements. Protein type had no effect on intake (Table 2).
Apparent digestibility
Both hydration and protein supplementation had no effect
(P>0.05) on apparent dry-matter digestibility though unhydrated
stover tended to have higher digestibility (Table 3).
346
Table 2. Dry-matter intake of hydrated and unhydrated stover
supplemented with nitrogen.
Stover intake (kg/d)
Protein Source Hydrated Unhydrated
~ ^ > / / a , f -,b,fControl 4.4 ' 3.4 '
Urea 4.9a'9 3.7b'g
Soyabean meal 4.8a,g 4.3b,h
Urea + blood-treated
soyabean meal 5.0 ' 3.5 '
Standard error of mean 0.086
a,b, means in a row with different superscripts differ
significantly (P<0.05).
f,g,h means in a column with different superscripts differ
significantly (P<0.05).
Table 3. Apparent digestibility of dry matter of hydrated and
unhydrated stover supplemented with nitrogen.
Apparent digestibility (%)
Protein source Hydrated Unhydrated
Control 49.87 59.03
Urea 51.10 52.10
Soyabean meal 47.51 50.45
Urea + blood- treated
soyabean meal 48.60 45.41
Standard error of mean 8.826
Rumen digestion parameters
Soyabean meal decreased the 'a' fraction for hydrated stover
but had no effect on the 'a' fraction of the unhydrated stover
(Table 4). Urea decreased (P<0.05) the 'b' fraction in the
hydrated stover and all the protein supplements tended to
increase the rate of degradation though only significantly for
347
the hydrated stover (Table 4). The patterns of DM degradation
for the hydrated and unhydrated stovers are shown in Figures 1
and 2 respectively. In both cases only the control treatments
show a distinct deviation from the other treatments.
DISCUSSION
Hydration increased intake but had no effect on digestibility,
a result that agrees with those obtained by Chatuverdi et al
(1973) who used soaked wheat straw. However, Devendra (1983)
reported negative effects on intake and digestion of wetted
rice straw by sheep. This discrepancy in research results may
be due to differences in species of animals and straw used. On
the other hand, it may be caused by differences in soaking and
as such it merits further research. Data on soaking maize
stover were not found in the literature.
Supplementation of poor quality roughages with nitrogenous
material is a common practice among farmers, often leading to
increased intakes. Our results showed a similar effect though
the low level of response (about 10%) was disappointing. The
supplements were chosen to represent a rumen-degradable non
protein nitrogen source, a rumen-degradable protein nitrogen
source and a combination of a rumen-degradable nitrogen source
and a rumen-undegradable nitrogen source. No differences in
intake, digestibility or rumen digestion kinetic parameters
were noted between all the nitrogen sources.
All the rates of digestion for the 'b' fractions were
similar but this may have been caused by high variabilities
within each treatment, thus masking any possible real
differences. Further experiments on this issue are in
progress.
348
(TJ
*->
2
<-> C
O) o■r- L.
^2
^ ■E»* 3v-'
"8u
<t->7
i_
*
ac
S*-»
(O
l_
T2L
^ -e
*e ^**
"SXI *->
(0
I-
*
3:
"S*->
to
1_
"£
^ £*« =3*■*
*(0
5 3 3
H- o) O) O)
in * Cg eg
in o PS *o
*
N (M S
I
5
2
8
X)
3 - 1
111
C XI O TJ
3 &
8 •
o ^
c -^
(0 •-
»-■
c
4) M £ -
.i: o •- —
Bill
<_> 3 (/) 3
349
Pipurc I. Dry-innltftr <lisnp»cnroncc from hydrilled nuuv.c stover incubnlcd in
nylon biifjs in the rumen of steers.
(#) onNrRor.
(^) UltLA
f\) SOYAI1EAN MEM.
 
(CI) UREA + BLOOD-COAXED
SOYABEAN MEAL
12 24 36 -10 60 72 84 96
TTMK (HOURS)
350
I'igure 2. Dry uiutlcr disiippcnruncc from wihydrutud mni/.o Klovor iitcuhiitctl in nylon
bags in the rumen of steers.
 
[m) ooniijol
(0) UREA
(y) SOYABEAN MEAL
UREA + BLOOD-OQATED
SOYABEAN MEAL
12 24 36 4S 60 72 84 96
TIME (IKXJRS)
351
CONCLUSION
Hydration increased DM intake but had no effect on apparent DM
digestion and on nylon bag degradation parameters. Protein
supplementation increased DM intake over and above that due to
hydration but the response was low. In situations where
nitrogen sources are scarce or expensive, hydration offers a
cheap and unhazardous method of increasing intake of maize
stover.
ACKNOWLEDGEMENTS
We thank the University of Zimbabwe Research Board for
financial assistance, Dr. D. Neeley, Department of Animal
Science, for help with statistical analysis and Messrs C. Mare,
J. Sena and J. Ualter for technical assistance.
REFERENCES
Chaturvedi, M.L.; Singh, U.B. and Ranjham, S.K. 1973. Effect
of feeding water-soaked and dry wheat straw on feed
intake, digestibility of nutrients and VFA production in
growing zebu and buffalo calves. Journal of Agricultural
Science, Cambridge 80: 393-397.
Devendra, C. 1983. Physical treatment of rice straw for goats
and sheep and the response to substitution with variable
levels of cassava, leucaena and gliricidia forages.
MARDI Research Bulletin 11(3): 272-290.
352
Doyle, P.T.; Devendra, C. and Pearce, G.R. 1986. Rice straw as
a feed for ruminants. IDP, Canberra, Australia.
Orskov, E.R. and McDonald, I. 1979. The estimation of protein
degradabi I i ty in the rumen from incubation measurements
weighted according to rate of passage. Journal of
Agricultural Science, Cambridge 92: 499-503.
Snedecor, G.W. and Cochran, W.G. 1967. Statistical methods.
7th edition. Iowa State University Press, Ames, Iowa.
Welch, J.G. 1982. Rumination, particle size and passage from
the rumen. Journal of Animal Science 54: 885-894.
353
IMPROVING THE INTAKE AND UTILIZATION
OF BY-PRODUCT-BASED DIETS
M. A. El-Naga
Faculty of Agriculture, University of Alexandria
Alexandria, Egypt
ABSTRACT
The voluntary feed intake or chopped corn stalks was improved
(23%) by just increasing moisture content from 30 to 60%. Due to
such treatment, sheep performance turned from losing 54
g/head/day to gaining 21.3 g/head/day. Addition of 5% linseed
meal doubled the consumption of corn stalks and resulted in a
daily gain of 53 g/head/day. Such percentage of linseed meal was
comparable to 20% concentrate mixture supplement.
Supplementation of the urea treated corn stalks with 1.5%
urea and 3% molasses improved the intake by 63%. Supplements
varied in their effect on consumption, however, it did not affect
the TDN content of the supplemented diet.
Recognising the deficient minerals in a by-product based
diet (by mineral balance trials) and supplementing the diet with
the recognized deficient amounts of minerals, resulted in
improving the TDN content, the rate of body weight gain and the
kg feed/gain ratio.
INTRODUCTION
Feed intake of agricultural by-products is mostly below the
required level to maintain the animal's body weight. Its tough
texture, poor digestibility and nutrient deficiencies all
contribute to its low level of consumption.
354
This present paper describes some approaches to improve both
the voluntary feed intake of by-products based diets and the
efficiency the animal utilizes such diets. Moistening,
supplementing and compensating for deficient minerals were tried
as feasible methods of improvement.
MATERIALS AND METHODS
Experiment 1. Effect of moistening the by-product-based diet on
its voluntary feed intake by sheep
A group (10 animals) of Barki male sheep of an average body
weight of 30 kg was fed a diet of chopped (3-5 cm) corn stalks to
which molasses, urea, vitamin A and minerals were added (Table
1). Moisture content of this diet was 30%. It was increased by
water addition in two steps, e.g., 47 and 60% voluntary feed
intake was measured at the three moisture levels. Measurement of
intake was made in the third week of each treatment.
Table 1. Composition of the corn stalks diet,
Ingredients Per cent
Chopped corn stalks 86
Molasses 10
Urea 1.5
Vitamin A 0.1
*
Mineral mixture 2.4
Crude protein 7.9
TDN 52
Composition of the mineral mixture was (%): 36 magnesium
sulphate, 0.8 zinc oxide, 1.2 manganese oxide, 14 ferrous
chloride and 48 bone meal.
355
Experiment 2. Effect of some supplements on the voluntary feed
intake
Chopped corn stalks were fed to a group (10 animals) of 32 kg
Barki male sheep for two weeks. Voluntary feed intake was
measured during the last 5 days of the two weeks experimental
period. Supplements which are shown in Table 2 were tested in
sequence. The TDN content of the diet with each supplement was
conventionally estimated using two male sheep.
Table 2. The tested supplements to the corn stalks-based diet,
1 . Corn stalks (CS)
2. 1% urea + 0.1 % vitamin A
*
3. 30% concentrate mixture
4. Treatment with 5% urea solution
5. 1.5% urea + 3% molasses
**
6. 0.3 phosphoric acid + 0.1% minerals
7. 20% concentrate mixture + 1% Ca carbonate + 0.1% minerals
8. 5% linseed meal
* Contains (%): 2 g cottonseed meal, 30 yellow corn, 30 wheat
bran, 5 rice bran, 3 molasses, 1 salt and 2 Ca carbonate.
** Contains (%): 36 magnesium sulphate, 0.8 zinc oxide, 1.2
manganese oxide, 14 ferrous chloride and 48 bone meal.
Experiment 3. Effect of compensating for recognised deficient
minerals on the TDN content and on the performance
of buffalo calves fed the same diets after mineral
supplementation.
Three diets containing rice straw at a rate of 40 to 55%
(Table 3) were fed to three groups (10 heads per each diet) of
356
buffalo calves. Growth rate and the kg feed/gain ratio were
measured. The initial body weight of the animals was about 200
kg. Digestibility and mineral balance trials were conducted
conventionally on two male animals. The recognised deficient
mineral amounts were added to each diet and all parameters were
measured again.
Table 3. Composition of the experimental diets.
Per cent
Ingredients 1 2 3
Rice straw 40 55 43
Berseem has 10 25 -
*
Concentrate mixture 40 7.5 14
Molasses 6 8 8
Urea 1. 5 1.5 2
Minerals and vitamin A 2. 5 3 3
Horsebean straw - 30
* Composition of concentrate mixture (%): 29 cottonseed meal, 30
yellow corn, 30 wheat bran, 5 rice bran, 3 molasses, 1 salt
and 2 Ca carbonate.
RESULTS
Experiment 1. Effect of moistening a corn stalks-based diet on
its consumption by sheep
About 23% improvement in sheep intake was induced by just adding
water to the by-products diet (Table 4). The body weight change
was negative before moistening and it turned to positive at 15
g/head/day (Table 4). Improvement due to raising moisture from
30% to 47% was less than that due to increasing it to 60%.
357
258 -54
280 0.0
319 15
Table 4. The voluntary feed intake (on DM basis) and body weight
changes of sheep fed chopped corn stalks of different
moisture contents.
Voluntary body weight
Moisture content Feed Change kg feed/gain
% intake (g/head/day) ratio
30
47
60 21.3
Experiment 2. Effect of some supplements on the voluntary feed
intake and TDN content of the corn stalks-based
diet
Table 5 shows the response of voluntary feed intake of sheep and
TDN content of the corn stalks-based diet to different
supplements. Urea supplementation at the rate of 1% improved the
feed intake by about 25%. Combining urea treatment with urea
addition resulted in 63% improvement in intake. Supplementation
with concentrate mixture (30%) resulted in 47% increase in the
intake. Combining concentrates with minerals raised the rate of
improvement to 78%. Linseed meal at a rate of 5% was as effective
in improving intake almost as 20% concentrate mixture plus
minerals.
358
Table 5. Effect of different supplements on the voluntary feed
intake and TDN content of corn stalks-based diet.
Voluntary feed T 0 N X
Added supplement intake (g/head/day) on DM basis
1 - No supplement 563 54
2 - 1% urea and 0.1% vit. A 706 55
3 - 30% concentrate mixture 832 56
4 - Treatment with 5% urea 814 54
5 - Treatment with 5% urea
+ 1.5% urea ♦ 3% molasses 920 56
6 - Treatment with 5% urea + 0.3%
*
phosphoric acid + 0.1% minerals 774 54
7 - 20% concentrates mixture +
1% Ca carbonate + 0.1% minerals 1003 56
8 - 5% linseed meal 968 55
* Its content is (%): 36 magnesium sulphate, 0.8 zinc oxide, 1.2
manganese oxide, 14 ferrous chloride and 48 bone meal.
** Its content is (%): 25 cottonseed meal, 30 corn, 30 wheat
bran, 5 rice bran, 3 molasses, 1 salt and 2 Ca carbonate.
Experiment 3. Effect of adjusting the mineral pattern of the diet
according to the results of balance experiments, on
the diet's nutritive value and efficiency
The results of some mineral balance experiments are shown in
Table 6. The negative balances of some minerals were corrected by
adding the corresponding deficient amount of salt to the diet.
359
Table 6. Balance of some minerals measured on buffalo
calves fed the three experimental diets.
Diet number
Mineral (g/head/day) 1
Ca
P
Na
K
Fe
Cu
Zn
Mg
Mn
-10 -14 -13
14 7 4
2 13 5
12 16 -13
-2 -1 -1
0 0.2 -1
0 0 0
1 2 2
0.1 0 0.4
The TDN contents, body weight gain and the kg feed/gain
ration, measured before and after this adjustment are presented
in Table 7. Diet 3 showed more mineral deficiencies than the
other two diets. Accordingly, it benefited more from compensating
for the recognised deficient minerals. This could be judged from
the improvement of daily body weight gain and kg feed/gain ratio
(Table 7).
DISCUSSION
Increasing the moisture content of corn stalks improved its
intake, and resulted in better utilization of the consumed
amount. It is just some calculated amount of water, added to the
diet of sheep losing weight that turned the situation to gaining
weight. The details of such a phenomenon is not understood yet.
This is a point that needs to be investigated further to make
better use of it with tough by-products feed. The present results
in this connection draw the attention to try levels of moisture
higher than that presently tested (60%). It is thought that this
is the simplest and cheapest method of treating poor quality by
products.
360
Table 7. The TON, body weight gain and kg feed/gain ratio
measured on buffalo calves fed the three experimental
diets, before and after adjusting the mineral pattern of
the diets.
Diet number
I tem 1 2 3
TDN(%):
Before 51 51 58
After 59 61 64
Gain (kg/head/day):
Before 0.65 0.68 0.25
After 0 = 87 0.79 1.10
Kg feed/gain ratio:
Before 8.4 13.9 24.2
After 6.4 10.0 7.1
Ammonia treatment showed to be very effective in improving
the level of voluntary feed intake of chopped corn stalks.
Supplementing the ammonia- treated material with urea (1.5%) again
improved the level of voluntary feed intake. The alkaline
treatment helped through the process of del ignif ication or
dislocation, while urea addition enriched the protein level in
the diet. However, linseed meal at a level of 5% was equivalent
or even better than the combined alkaline treatment and urea
addition. The cheaper of these two treatments would be the clue
to improving the intake and perhaps the better utilization of
such by-products. It was very interesting to observe that TDN
content of any of the supplemented (Table 5) diets was almost
constant. Since the rate of defecation is a reflection of the
rate of ruminal outflow, it could be concluded that the tested
supplements (Table 5) exerted its improving effect on intake by
increasing the rate of ruminal outflow without increasing the
extent of digestion.
361
The approach of investigating the mineral balance on a diet
and supplementing the diet with the deficient amounts of minerals
showed to be very effective in improving the feeding value of the
by-products based diets (Table 7). The accumulated experience in
this connection showed the significance of adjusting the Ca/P and
the adequacy of K and Na. This approach showed frequently that
minerals which may be estimated in a diet would not necessarily
be of value for the animal because they may be unavailable to a
certain degree or even completely. This means that some diets
would contain high levels of some minerals even though there may
be a need to supplement with such minerals. Availability of
minerals is suggested to be estimated besides the estimation of
the minerals themselves. This will be an important clue to the
improvement of the by-products consumption and utilization.
362
THE DEGRADATION OF UNTREATED AND TREATED MAIZE COBS
AND COCOA POD HUSKS IN THE RUMEN
A.K. Tuah1 and E.R. Orskov2
Department of Animal Science, Fac. of Agric. U.S.T., Kumasi, Ghana
2
Rowett Research Institute, Bucksburn, Aberdeen, Scotland, U.K.
ABSTRACT
The dry-matter disappearance (DMD) values of untreated, 3.5%
ammonia-treated and water-soaked maize cobs and cocoa pod husks
were determined in the rumen of cannulated steers using the
nylon bag technique. Although cocoa pod husks contained a
higher level of lignin (26.38%) than the maize cobs (9.60%),
the DMD values of the untreated cocoa pod husks were greater
than those of untreated corn cobs for all the incubation
periods (of 44% and 34% at 48 h). Ammonia treatment of maize
cobs increased the DMD values but soaking it in water for 24 h
before incubation had no significant effect. Cocoa pod husks
were not improved by ammonia treatment.
The maize cobs and cocoa pod husks were treated with
different levels of sodium hydroxide, 0,6,8,10 and 12 g/100 g
of product and incubated in the rumen of four sheep for 48 h.
Sodium hydroxide treatment significantly (P<0.01) increased the
DMD values of the products. Washing the products after sodium
hydroxide treatment did not significantly (P<0.05) affect the
DMD values of the maize cob. With cocoa pod husks, washing
after sodium hydroxide treatment caused a significant (P<0.01)
reduction in the DMD values because of losses of soluble
fractions during washing.
INTRODUCTION
In many tropical areas there is a problem of inadequate feed
supply during the dry season. Agricultural wastes and by
products could be fed to ruminants during this season to offset
the detrimental effects of inadequate nutrition on reproduction
and growth.
363
In Ghana, there are large quantities of cocoa pod husks
and maize cobs which could be fed to ruminants but are allowed
to waste. Ghana produced 639,000 metric tonnes of dry cocoa
pod husks in 1982 (Tuah et al, 1985) and about 95,000 metric
tonnes of maize cobs in 1984 (FAO, 1984). Collection of maize
cobs is easier than that of maize stalk which is left in the
field where the maize is harvested while the cobs are gathered
before dehusking and shelling.
Very little work has been done in Ghana to evaluate
these by-products as ingredients in ruminant diets (Otchere et
al, 1983; Tuah et al, 1985; Adomako and Tuah, 1987). This
study was therefore undertaken to determine in j_n situ
degradation characteristics of the two by-products.
The effects of soaking, ammonia and sodium hydroxide
treatments on the degradation of the by-products in the rumen
were also studied.
MATERIALS AND METHODS
Cocoa pod husks and maize cobs
The cocoa pod husks was prepared from fresh ripe pods as
described by Tuah et al (1985). The maize cobs were obtained
from the Ghana Seed Company, Kumasi and they were from an
assortment of Ghanaian varieties both materials were sun-dried
prior to handling.
The cocoa pod husks and the maize cobs were ground
through a laboratory hammermi 1 1 with a screen size of 2.5 mm.
About 0.5 kg each of these products was treated with anhydrous
ammonia as described by Orskov et al (1983) using 3.5 g NH,/100
g of product. Samples of the products (100 g each) were
treated with different quantities of sodium hydroxide dissolved
in 100 ml of water. The levels of sodium hydroxide applied
were 0,6,8,10 and 12 g NaOH per 100 g of air-dry weight of the
material. The treated samples were kept in polythene bags in a
364
laboratory (about 20 C) for 48 h. After this period each
sample was divided into two halves: one half was dried in an
oven for 48 h at 60 C. The other half was put into nylon bags
and washed in a washing machine for about 15 minutes. They
were then dried at 60 C for 48 h.
Animal feeding and management
Three rumen-cannulated steers (average weight 474 kg) and four
rumen- cannulated sheep (average weight 63 kg) were used. The
type of cannual and the procedures for cannulation are as
described by Ganev et al (1979). The management and feeding of
the animals were as described by Tuah et al (1986).
Procedures of incubation for the determination of dry-matter
disappearance (DMD)
Samples (2 g each) of untreated, ammonia-treated and water-
soaked maize cobs and cocoa pod husks were incubated in the
same manner as described by Tuah et al (1986). The equation of
Orskov and McDonald (1979) was used to describe the course of
digestion of each sample. The a,b,c, and asymptote values for
each sample were determined. For the NaOH treated samples,
they were incubated for 48 h in the rumens of sheep.
Chemical analysis
The untreated cocoa pod husks and maize cobs were analysed for
nitrogen (N) by the automated Kjeldahl method of Davidson et al
(1970) and dry matter (DM) by the AOAC (1975) method. They
were also analysed for acid-detergent fibre (ADF), neutral-
detergent fibre (NDF) and lignin using the methods of Van Soest
(1963) and Van Soest and Wine (1967). The hemicel lulose
content was estimated as the difference between NDF and ADF
(NDF-ADF). The cellulose content was estimated as the
difference between ADF and lignin (ADF- I ignin). Cell content
was estimated as 100-NDF.
365
Statistical analysis
The data were subjected to statistical analysis using the two-
way analysis of variance for the steer experiments and split-
plot analysis of variance for the sheep experiment (Snedecor
and Cochran, 1976).
RESULTS
Chemical composition of the products
Table 1 contains the chemical composition of the untreated
maize cobs and cocoa pod husks (Table 1 near hear). When these
products were treated with ammonia, the nitrogen contents
increased from 0.50 to 1.29% for maize cobs and from 1.12 to
3.53% for cocoa pod husks.
Degradation characteristics of the untreated and treated
products
The degradation characteristics of untreated, ammonia-treated
and water-soaked maize cobs and cocoa pod husks are shown in
Table 2. (Table 2). Soaking the samples in water for 24 h
increased the moisture content of the maize cobs to 76.7% and
that of cocoa pod husks to 93.0%. Ammonia treatment of the
maize cobs increased its DMD values. The increases were
significant at 72 h (P<0.05) and 96 h (P<0.01) (Table 2).
Ammonia treatment of the cocoa pod husks significantly
(P<0.05) increased the DMD value only at the 12 h incubation
period. The DMD values of the ammonia- treated samples were
less than those of the untreated samples at 48, 72 and 96 h
incubation periods, the difference being significant (P<0.05)
at 72 h.
Soaking the maize cob samples for 24 h before incubating
in the rumen did not markedly increase the DMD values compared
to the untreated samples. The DMD values of water-soaked cocoa
pod husks were very low after correcting for soaking losses and
therefore were not included in the statistical analysis of the
cocoa pod husks data.
366
Table1.Ehemicalcompositionfuntreat dm izbandc oapusk.
Ehemicalconst tuent(g/100M)
EM(%)AshEF9FLigninelluloseH micel uloseN tr g necontent
u>Maizecob00.271.50E 6150938 01466 04
Eocoac b
Husk89.5010 025 63426 84 2.7148
^iC
EM=drymatter.
AEF=acid-detergentf br .
9F=neutral-dete gentfibre.
Table1.Degradationchar cteristicsofunt ea d,ammon a1treatednwater1so kem izbcocop
(fittedvaluesinparen h s s).
DHDvaluestthariouincuba ionAsymptote
periods(g/100DMincubated)
incubated)abR12
112D" §BUntreatedmaizcob11.412 03•*455
(10.9)6 11 03545 46 .611.16 .30.03 1
Ammonia1treatedmaizecob11.66 03 44 55563
(11.1)6 5)3 446.1255 961.360.0 084 4
Water1soakedmaizcob11.55 1639 44 6D.1 (10.4)1 1)239 545.9D.65011 060. 3561 1
18D
1.57"D9N1"066 **0 1
Untreatedcocoap,sk11.0330 1435
(12.5)9 130 3(435 . )12 6.141 50.01341 0
I
g
8
■8
S
"8
U
(A (A
O 4)
.C.*-> 4->
(A c
OJ(_ L.
<D 9*-> cL
£ c
t_fl>
.e
o S>
S (0>*->
1"8 *->(_ +■>
O)
<u <4-
Q s-^
fVJ
0>
■8
5 -
4-> O) o
o
s |
.M
*J
i »</)
I-» ■?
si
.2 i!
<Q
> z
Q
JC O)
o
4-> O
<0 «-
s ~
8.
E
ro
o
d
Oj
o
r\j
o
ro-*
z
s•J- «*
3 ro
*
o
r\J r^
,J CO ,J•>* ^r
CO
z
f>
CO l^ >».
d d ro"
>t
00
o r*.
in«*
3 tn «-
00
8
o r«-
CO
fM
CO f\J
rvi
ro
eg
ro f>
(\j «J*"" ^
o o
ro r^
I
"8
MOO
*-> d o
8v v
o. a.
1 i
369
The effects of different levels of ammonia and sodium
hydroxide treatments of maize cobs and cocoa pod husks on 48 h
DMD values are shown in Table 3. The DMD values were
significantly <P<0.01) affected by the level of sodium
hydroxide treatment. For the maize cobs, washing the samples
after sodium hydroxide treatment had no significant (P<0.05)
decreasing effects on the DMD value (means: 72.6% for unwashed
and 63.3% for washed, SED 6.48). For the cocoa pod husk,
washing the samples after sodium hydroxide treatment
significantly (P<0.01) reduced the DMD values (means 35.7% for
the washed and 43.9 for the unwashed, SED 2.58).
Table 3. The effect of different levels of sodium hydroxide
treatment and ammonia treatment on the 48 h DMD values
of maize cob and cocoa pod husk.
48h DMD values (g/100 g DM incubated)
Level of sodium hydroxide (%)
0 6 8 10 12 Ammonia-
treated
SED
Maize cob (not washed) 35.6 68.9 81.0 85.3 90.6 45.3 3.36
Maize cob (washed) 32.0 60.0 79.0 82.4 84.2 ND 2.21
Cocoa pod husk (not washed) 40.6 41.6 43.5 47.5 59.2 39.4 1.49*
Cocoa pod husk (washed) 26.5 28.8 36.2 39.7 47.5 ND 1.28*
DMD = dry-matter disappearance.
SED = standard error of the difference.
ND = not determined.
** = P<0.01
370
DISCUSSION
Degradation characteristics of untreated and water-soaked
maize cobs and cocoa pod husks
At all the incubation periods the untreated cocoa pod husk had
higher DMD values than the untreated maize cobs although the
lignin content of cocoa pod husks was about three times higher
than that of maize cobs. This to some extent disagrees with
the theory of physical encrustation and entrapment of nutrients
within lignified cell walls which Van Soest (1982) also
disagrees with. With the maize cobs, most of the material was
cell wall while the cocoa pod husk had a cell content of about
40.6% compared to 6.04% for the maize cobs. The hemicellulose
content of the maize cobs was very high (46.4%) compared to
that of cocoa pod husk (8.7%). Hemicellulose is more closely
associated with lignin than any other polysaccharide fraction
and is believed to be bonded to phenolic constituents (Van
Soest, 1982). The cellulose and the hemicellulose of the maize
cobs may therefore not be made readily available for microbial
degradation, thus decreasing its DMD value. The cocoa pod husk
on the other hand had high cell contents which were readily
soluble. The dry-matter losses after 24 h soaking were 25.6%
for cocoa pod husk and 3.0% for maize cob.
The cell wall of cocoa pod husk is relatively rich in
pectin (about 11% of whole product on DM basis), which is
totally digestible in the digestive tract of the sheep (Adomako
and Tuah, 1987) and low in hemicellulose. Adomako (1975)
reported that cocoa pod husk has very short fibres. It is
371
therefore interesting to note that it has a high lignin
content. It is possibly not totally lignin but also some
amounts of condensed tannins. Further work to characterise
this "lignin" will be pursued.
Bateman and Fresnilo (1967) reported that in vivo dry-
matter digestibility of cocoa pod husks ranged from 32.3 to
39. 7% which were close to the 24 h and 48 h DMD values observed
in the present trial.
Kevelenge et al (1983) reported that the organic matter
digestibilities of maize cob incubated in rumen fluid for 24,
48, 72 and 96 h followed by 48 h acid-pepsin digestion were
about 8, 15, 26 and 50% respectively. Except for the 96 h
period these values of Kevelenge et al (1983) were lower than
those obtained in the present trial although the lignin content
of their maize cobs was lower than that used in the present
trial (5.8% vs 9.60%).
In the present trial soaking in water for 24 h did not
increase the DMD values of the maize cobs at the various
incubation periods as postulated by Kevelenge et al (1983).
With cocoa pod husk, soaking in water for 24 h caused
reduction in the DMD values at the various incubation periods
when soaking losses were corrected for because great quantities
of cell contents were dissolved in the water. There seems to
be no advantage in soaking any of the products, especially
cocoa pod husks.
372
Degradation characteristics of ammoni a- treated maize cob
and cocoa pod husk
The DMD values of the ammoni a- treated maize cobs were
significantly improved only at 72 h (P<0.05) and 96 h <P<0.01)
incubation periods compared to the untreated or water-soaked
samples. It seems that anhydrous ammonia was not very
effective in improving the DMD values of the maize cobs used in
this trial.
Nelson et al (1984) using maize cobs containing 40%
moisture reported the 48 h DMD values of 2, 3 and 4% ammonia-
treated samples to be 61.30, 61.69 and 65.94% respectively.
These values were higher than the 48 h DMD values for ammonia-
treated maize cobs obtained in this trial. In the present
trial, the moisture content of the maize cob was 6.4%. Kiangi
and Kategile (1981) reported that moisture content of straws
(20 or 40%) had less effect on the rate of aimionia treatment in
improving their nutritive values. Borhami and Sundstol (1982),
however, reported that if moisture content of straw was not
above 2.5% then it adversely affected the improvement in its
nutritive value with ammonia treatment. It is most likely that
with maize cobs, the least moisture content for ammonia
treatment to be effective would be higher than that of cereal
straw. The optimum level of moisture content of maize cobs for
ammonia treatment will be studied.
Cocoa pod husk was not responsive to ammonia treatment
except at the 12 h incubation period although it caused an
increase in the N content of the product (1.12% to 3.53%). Van
Soest (1982) reported that grass lignin linkages are more
susceptible to mild alkali treatment than those of wood or non
373
grass forages due to the higher content of ester and a lower
content of methoxyl groups compared to that of non-grass
lignin. The ester linkages between lignin and carbohydrates
are more easily cleaved by alkali than the other linkages.
Cocoa is a dicotyledonous plant which possibly explains the
unresponsiveness of its lignin to ammonia treatment.
Effect of level of sodium hydroxide treatment of maize cob
and cocoa pod husk on their 48 h DMD values
The level of sodium hydroxide treatment significantly (P<0.01)
improved the 48 h DMD values of maize cobs. The highest level
of treatment resulted in the highest DMD value. When the
sodium hydroxide- treated samples were washed after treatment to
reduce the sodium content the DMD values were not significantly
(P<0.05) reduced compared to the unwashed samples. The slight
reduction in the DMD values of the samples after washing could
be due to losses of water-soluble fractions and solubilised
phenolic compounds.
Kategile and Frederiksen (1979) reported jm vivo
organic-matter digestibility of 10% sodium hydroxide-treated
maize cobs to be 32.4%. Nagole et al (1983) reported that
treatment of maize cobs with 4.5% sodium hydroxide increased in
vivo dry-matter digestibility from 44.7 + 1.6 to 54.2 +2.0%.
The sodium hydroxide- treatment significantly (P<0.01)
increased the DMD values of the cocoa pod husks. Washing the
treated samples reduced significantly (P<0.01) the DMD values
compared to unwashed samples. This is because during the
washing process some of the soluble digestible portions were
lost.
374
CONCLUSION
The DMO value of maize cobs could be increased with sodium
hydroxide treatment and excess sodium could be washed from the
sample without affecting its nutritive value. Anhydrous
ammonia treatment was not very effective in increasing the DMD
value possibly due to the low moisture content. Cocoa pod
husks did not respond to anhydrous ammonia treatment but was
responsive to sodium hydroxide treatment. The lignin content
per se of a product is not directly related to the DMD values
as shown by cocoa pod husks and maize cobs in the present
trial.
ACKNOWLEDGEMENTS
The financial assistance given to one of the authors (A.K.Tuah)
by the Association of Commonwealth Universities is
acknowledged. Mr. R.I. Smart of the Rowett Research Institute
is thanked for the chemical analysis of the materials.
REFERENCES
Adomako, D. 1975. A review of researches into the commercial
utilisation of cocoa by-products with particular
references to the prospects in Ghana.
Research Review CMB Newsletter No. 61 pp.
12-20.
Adomako, D. and Tuah, A.K. 1987. Digestibility of cocoa pod
husk pectic polysaccharides by sheep fed rations
containing cocoa pod husk. 10th International Cocoa
Research Conference, 17-23/5/87, held in Santo Domingo,
Domi ni can Republ i c .
375
AOAC (Association of Official Analytical Chemists). 1975.
Official methods of analysis. 12th ed. AOAC,
Washington, D.C. U.S.A.
Bateman, J.V. and Fresnilo, 0. 1967. Digestibility of
Theobroma cacao pods when fed to cattle. J. Agric. Sci.,
Camb 58: 23-25.
Borhami, B.E.A. and Sundstol, F. 1982. Studies on ammonia-
treated straw. 1. The effects of type and level of
ammonia, moisture content and treatment time on the
digestibility in vitro and enzyme soluble organic matter
of oat straw. Animal Feed Sci. Tech 7: 45-51.
Davidson, J.; Mathieson, J. and Boyne, A.W. 1970. The use of
automation in determining nitrogen by the Kjeldahl method
with final calculations by computer. Analyst. London
95: 181-193.
F.A.O. (Food and Agriculture Organization). 1984. Monthly
bulletin of statistics. Vol. 7, No. 12. FAO, Rome,
Italy. p. 13.
Ganev, G.; Orskov, E.R. and Smart, R. 1979. The effect of
roughage or concentrate feeding and rumen retention time
on total degradation of protein in the rumen. J. Agric.
Sci., Camb. 93: 651-656.
Kategile, J. A. and Frederiksen, J.H. 1979. Effect of level of
sodium hydroxide treatment and volume of solution on the
nutritive value of maize cobs. Anim. Feed. Sci. Tech. 4:
1-15.
Kevelengo, J.E.E.; Said, A.N. and Kiflewahid, B. 1983. The
nutritive value of four arable farm by-products commonly
fed to dairy cattle by small-scale farmers in Kenya. I.
Organic structural components and .in vitro digestibility.
Trop. Anim. Prod. 8: 162-170.
376
Kiangi, E.M.I. and Kategile, J. A. 1981. Different sources of
ammonia for improving the nutritive value of low quality
roughages. Anim. Feed Sci. Tech. 6: 377-386.
Nangole, F.N.; Kayongo-Male, H. and Said, A.N. 1985. Chemical
composition, digestibility and feeding value of maize
cobs. Anim. Feed. Sci. Tech. 9: 121-130.
Nelson, M.L.; Klopfenstein, T.J. and Britton, R.A. 1984.
Protein supplementation of ammoniated roughages. Corn
cobs supplemented with a blood meal-maize gluten meal
mixture- lamb studies. J. Anim. Sci. 59: 1601-1609.
Orskov, E.R. and McDonald, I. 1979. The estimation of protein
degradability in the rumen from incubation measurements
weighted according to rate of passage. J. Agric. Sci.,
Camb. 92: 4990 503.
Orskov, E.R.; Roid, G.W.; Holland, S.M.; Tait, C.A.G. and Lee,
N.H. 1983. The feeding value for ruminants of straw and
whole-crop barley and oats treated with anhydrous or
aqueous ammonia or urea. Anim. Feed Sci. Tech. 8: 247-
257.
Otchere, E.O.; Musah, I. A. and Bafi-Yeboah, M. 1983. The
digestibility of cocoa husk- based diets fed to sheep.
Trop. Anim. Prod. 8: 33-38.
Snedecor, G.W. and Cochran, W.G. 1976. Statistical methods.
6th ed. Iowa State University Press, Ames, Iowa.
Tuah, A.K.; Adomako, D. and Dzoagbe, S. 1985. Evaluation of
cocoa pod husk as feed ingredient for sheep in Ghana.
Proc. 9th Intl. Cocoa Res. Conf. held at Lome,
Togo. pp. 505-509.
Tuah, A.K.; Lufadeju, E.; Orskov, E.R. and Blackett, G. 1986.
Rumen degradation of straw. I. Untreated and ammonia-
treated barley, oat and wheat straw varieties and
triticale straw. Animal. Prod. 43: 261-269.
377
Van Soest, P.J. 1963. Use of detergents in the analysis of
fibrous feeds. II. A rapid method for the determination
of fibre and lignin. J. Ass. Off. Anal. Chem. 46: 829-
835.
Van Soest, P.J. 1982. Nutritional ecology of the ruminant. 0
and B Books Inc., Corvallis, Oregon. pp. 112, 126 and
127.
Van Soest, P.J. and Wine, R.H. 1967. Use of detergents in the
analysis of fibrous feeds. IV. Determination of plant
cell wall constituents. J. Asso. Off. Anal. Chem. 56:
50-55.
378
POTENTIAL OF AGRICULTURAL BY-PRODUCTS AS SOURCES
OF MINERAL NUTRIENTS IN RUMINANT DIETS
E. Kabaija and D.A. Little
International Livestock Centre for Africa
P.O. Box 5689, Addis Ababa, Ethiopia
ABSTRACT
Several crop residues and agro- industrial by-products,
available in Ethiopia as potential ruminant feeds, were
examined in relation to their potential to supply essential
dietary minerals. In absolute terms, cattle diets based on
crop residues are unlikely to supply adequate Na, and are
marginal-to-deficient in P, Cu and possibly Zn, but these
problems, except for Na, seem rectifiable by the inclusion of
appropriate proportions of by-products in the ration. This
however, takes no account of the possibility that mineral might
be rendered to some degree unavailable through its association
with e.g. indigestible fibre.
Thus the apparent availability of minerals was assessed,
firstly following sequential extraction j_n vi tro in neutral,
acidic and alkaline solutions to simulate conditions
respectively in the rumen, abomasum and small intestine, and
secondly by analysis following intraruminal incubation in nylon
bags for 48 h; there was in general good agreement between the
two methods. However, it is notable that the j_n vi tro method
removed Ca from roughages much more efficiently, while the
reverse was true for the oilseed cakes, due possibly to
differing extents to which Ca is bound to fibre.
The apparent availabilities of Ca from wheat and teff
straws j_n vivo when fed to sheep were very similar to the
values obtained j_n sacco, much more so than for other minerals.
It was noted that roughage diets with low apparent mineral
availability had much of their intrinsic minerals in
association with faecal fibre. These could not be removed by
water. It may thus be useful to pay close attention to the
379
balance of minerals in diets based on fibrous crop residues
whose utilisation may have been improved through chemical
treatment of NPN supplementation.
INTRODUCTION
Feeding of agricultural by-products and crop residues to
livestock in the tropics is a common practice especially during
the dry season when the available pasture is of low quality.
These by-products have been evaluated mainly for their
potential as sources of energy and protein. Their role as
sources of mineral nutrients has received little attention.
Under most production systems in Africa, ruminant animals
rarely receive mineral supplements with the occasional
exception of common salt. Where multiple mineral supplements
are available, it is common to find some of them with essential
minerals either deficient or possibly in excess.
Strategies being proposed for future improvement in animal
production in Africa include identification and specification
of crop residues and agro- industrial by-products as livestock
feeds (Cianci and Hashi, 1985) and definition of improved means
of utilising them, since these materials have a potential role
to play in improving future animal production in Africa. Thus
these feedstuffs need to be fully assessed for their
suitability as livestock feeds, and any constraints that may
limit their utilisation identified. Samokhin (1981) suggested
that large amounts of coarse feedstuffs of cereal straw may
reduce the degree of utilisation of the minerals in the
feedstuffs. This could be due to large amounts of plant cell
wall materials that are resistant to digestion in the
gastrointestinal tract and which may shield nutrients from
being assimilated. This study was undertaken to characterise
various agricultural by-products for content and utilisation of
essential minerals.
MATERIALS AND METHODS
Samples were obtained of several agro- industrial by products,
mainly straws, brans and oilseed cakes, that are available in
380
Ethiopia as potential ruminant feeds. They were dried at 80 C,
ground through a 1 mm stainless steel sieve and digested using
H?S0, and H^Op for determination of K, Na, Ca, Mg, Mn, Fe, Zn
and Cu by atomic absorption spectrophotometry (Perkin Elmer,
1982), and for N and P following Kjeldahl digestion using an
autoanalyser (Chemlab Instruments, 1980).
Apparent availability of minerals in these materials was
examined:
a) J_n vi tro. using an adaption of the procedure described by
Naga (1986), in which 2 g samples were successively
extracted with neutral, acidic and alkaline solutions to
simulate pH conditions respectively in the rumen,
abomasum and small intestine. The solutions were
respectively 900 ml distilled deionized water + 36 g
NH4HC03(pH 6.8), 0.05M HCl + 0.09M KCU2.1) and 0.1M
NaHCOp (8.3), and the samples were incubated at 37 C for
12 h in each of them. The residues were drained, dried
and analysed as above, and the degree of disappearance of
each mineral calculated by difference and expressed as a
percentage.
b) J_n vivo, by incubating 5 g samples of each material in nylon
bags (120 x 80 mm, pore size 20 um) in the rumen of a
fistulated ox for 48 h. The ox was fed a ration of meadow
grass hay ad lib, 600 g noug cake/day and free access to a
mul ti -mineral block. After removal of the bags from the
rumen they were washed under hot running distilled water
until the washings were clear, dried at 100 C for 24 h,
the residues analysed and calculations made as above.
In order to estimate the proportions of mineral removed
from a fibrous feed during complete j_n vivo digestion, three
rations based respectively on meadow hay, teff and wheat straw
were formulated (Table 1) and fed to rams in wooden metabolism
cages. Each diet was fed to 4 randomly allocated sheep
(approx. 8 months old and weighing 21 kg) for 21 days following
which total faecal collections were made for 6 days, using
canvas faecal bags fitted with plastic liners. The faeces were
381
collected each morning, thoroughly mixed and 100 g samples
taken for analysis. Total feed intake was also determined
during this period, and the sheep had free access to distilled
water
throughout. Mineral determinations were made as described
above, and neutral detergent fibre analysed using the method of
Goering and Van Soest (1970). To quantify the amount of
minerals associated with faecal fiber, 0.5 g faecal sample in
9.5 ml of distilled water at 36°C were centrifuged for 10
minutes at 2000 r.p.m, the residue drained of excess water,
oven-dried and analysed for residual minerals as described
above.
Table 1. Composition and digestibility of experimental diets
(dry-matter basis).
Diet type
Meadow
hay
Teff
straw
Wheat
straw
Meadow hay - chopped (g/kg)
Teff straw - chopped (g/kg)
Wheat straw - chopped (g/kg)
Urea-molasses mixture 10% urea (g/kg)
Total nitrogen (g/kg)
NDF (g/kg)
Dry-matter intake (g/day)
Faecal output (g/day)
Faecal NDF (g/kg)
Dry-matter digestibility (g/kg)
650
650
- - 650
350 350 350
22.0 19.0 18.4
468 463 461
677 612 467
176 197 163
615 627 688
740 680 650
RESULTS AND DISCUSSION
Mineral contents of the feedstuffs are shown in Table 2. All
the feedstuffs had adequate quantities of K except for sorghum
bran and brewer's dried grains (BDG) whose K content was below
382
the dietary critical level of 6.5 g/kg given by NRC (1984) for
beef cattle. Low K content in BDG has been reported by workers
elsewhere (NAS, 1971), and could be a contributory factor in
lowering the nutritional value of diets with BDG levels
exceeding 40% (Couch, 1976). It may thus be necessary to
undertake K supplementation if ruminant diets contain more than
40% BDG and especially if crop residue feeding is involved.
Most of the feedstuffs were deficient in Na with the exception
of oats straw, poultry wastes, molasses and cottonseed cake
whose Na contents were above the levels of 0.7 to 1 g/kg
considered by most workers (Morris, 1980; Underwood, 1981 and
Little, 1987) to be the critical range for cattle. Based on
the data shown, it would be beneficial to offer supplementary
Na if most of the feedstuffs are fed to livestock especially
the crop residues.
Levels of Ca below 3.0 g/kg were found in most oilseed
cakes and cereal brans. Levels below 2 g/kg are likely to be
inadequate by most standards (NRC, 1984, 1985; ARC, 1980). The
very high P content relative to Ca in oilseed cakes could
exacerbate the low Ca effect. Though ruminants have been found
to tolerate very wide Ca to P ratios in instances where Ca is
higher (Leuker and Lofgreen, 1961), there is little information
on the effect of higher P content relative to Ca in diets of
ruminants. In poultry, higher P in diets with adequate Ca
resulted in leg bone abnormalities (Smith and Kabaija, 1985)
which was probably due to the impairment observed in Mn
metabolism. The case deserves investigation in ruminants.
Underwood (1981) considered a dietary P level of 1.7 g/kg
to be marginal for grazing animals. Little (1980, 1985)
indicated a figure of 1.4 g/kg to be the minimum required for
growing cattle.
The present data show most cereal straws to be marginal-
to- deficient in P and supplementation with P to such diets is
likely to be beneficial. Animals on smallholder units which
may receive concentrate feeds may have adequate P if offered
high protein oil seed cakes or cereal brans.
383
Table 2. Mineral content of agricultural by-products used as
ruminant feeds (dry-matter basis).
K Na Ca P M_a £e Mn In Cu
Feedstuff g/kg mg/kg
Uheat straw 14..8 0.3 4.1 1.3 1.5 325 78 11 3.0
Barley straw 10..7 0.5 4.6 1.9 1.4 1175 90 12 5.0
Teff straw 11..7 0.3 4.3 1.6 1.9 170 59 26 6.5
Linseed straw 10..7 0.6 7.7 1.3 1.0 103 71 24 14.0
Rough pea straw 21..5 0.4 11.4 1.7 1.9 418 52 28 11.0
Oats straw 17..7 2.0 3.9 1.7 1.8 196 191 17 14.0
Maize stover 17,.8 0.5 3.3 1.7 2.5 408 61 24 5.9
Coffee pulp 17..0 0.5 6.5 1.8 1.1 742 34 12 6.0
Wheat bran 11..2 0.4 1.2 6.3 5.2 163 172 75 7.6
Sorghum bran 6..0 0.4 0.6 6.1 2.2 163 29 25 5.0
Broiler litter 14,.2 6.0 15.7 7.2 5.3 149 451 150 49.0
Cage layer
excreta 14..6 5.5 30.5 18.9 7.2 186 601 547 24.0
Noug cake 11.,4 0.2 3.5 6.6 5.3 272 160 84 24.0
Sunflower cake 10..8 0.1 1.9 6.8 4.9 189 42 94 16.0
Rapeseed cake 9..8 0.3 4.7 13.4 4.3 161 169 89 13.0
Cottonseed cake 12..5 1.4 1.8 9.6 4.8 56 21 56 11.0
Groundnut cake 10,.6 0.3 1.0 7.1 3.9 1183 58 51 15.0
Linseed cake 10,.5 0.5 6.5 9.0 4.6 149 144 70 31.0
Brewer's dried
grains 0,.2 0.4 4.1 5.3 4.8 403 71 109 12.0
Molasses 58,.4 1.4 11.2 1.1 2.1 359 21 26 17.2
Levels of Mg, Fe and Mn in most feedstuffs were much
higher than the levels of 1 g, 50 mg and 40 mg/kg respectively
proposed as adequate for grazing animals (McDowell, 1985). The
straws could however offer marginal Mg in case of high
producing animals. Kemp (1960) proposed 0.20% Mg in herbage as
the lowest safe level while Metson et al (1966) showed with
384
beef cattle that a safe level of Mg in the forage may be even
higher than 0.25%. McDowell et al (1978) considered 30 mg/kg
to be a critical level of dietary Zn, although the ARC (1980)
suggested that concentrations of 12-20 mg/kg are adequate for
growing cattle. The cereal straws and coffee pulp may thus
constitute a marginal supply of Zn. The necessity for
supplementary Zn needs to be kept under review particularly for
sheep which require some 35 mg Zn/kg diet (ARC, 1980).
The dietary requirement of cattle for Cu is considered to
lie in the range of 8-U mg/kg (ARC, 1980; NRC, 1978; NRC,
1984). The cereal straws and brans will provide def icient- to-
marginal levels of this element. This situation may be
exacerbated by high Fe levels in the straws (Standish et al,
1971) that may be both intrinsic to the feed as well as from
soil contamination. It is thus necessary to consider Cu
supplementation when straw-based diets are fed to cattle. This
may, however, not be necessary for sheep, as this species'
requirement is only about 5 mg/kg.
The j_n vi tro availability of Ca, Mg, Fe, Mn, Zn and Cu
from the feedstuffs is shown in Table 3. K and Na
availabilities were not estimated because KC1 and NaHCO, were
components of the extracting solutions. Availabilities of Ca,
Mg and Mn were high in most feedstuffs especially straws.
Availabilities of Fe, Zn and Cu were low. Low Fe
availabilities have been reported before in non-ruminant diets
(Underwood, 1977) but little is known of the physiological
availability of iron from feeds to ruminants. Low Zn and Cu
availabilities could exacerbate deficiencies of these elements
particularly in straws where their concentrations were
marginal-to- deficient. The method used in the present study
does not accurately represent conditions in the digestive tract
because factors involved in the kinetics of mineral elements
are very complex and difficult to duplicate j_n vi tro. The
method is, however, an attempt at the characterisation of the
nature of mineral forms found in the feedstuffs.
385
Table 3. In vitro mineral availability (%) from
agricultural by-products.
Ca Mg Fe Mn Zn Cu
Wheat straw 73 86 31 67 11 57
Barley straw 76 76 25 65 19 41
Teff straw 80 89 38 77 28 49
Maize stover 79 84 27 59 8 38
Oats straw 72 83 49 74 24 55
Coffee pulp 45 54 15 32 25 19
Wheat bran 83 94 45 88 62 56
Sorghum bran 100 77 8 55 32 28
Brewer's dried
grains 61 93 31 52 30 29
Noug cake 11 55 22 32 27 21
Sunflower cake 42 77 41 48 14 37
Rapeseed cake 6 56 19 38 18 31
Cottonseed cake 72 83 36 43 33 42
Groundnut cake 50 87 51 45 41 49
Linseed cake 60 43 34 26 33 27
Cage layer
excreta 37 35 5 8 22 38
Broiler litter 24 55 11 13 15 31
Percentage mineral disappearance from most feeds in
sacco was high for K, Na and Mg (Table 4). Similar findings
were reported by Rooke et al (1983) who observed high values
for Na, Mg and K from silages incubated in nylon bags in rumen
of cattle. This probably is due to these elements existing in
readily soluble ionic forms. Lower values observed in this
study for Mn, Fe, Zn and Cu are comparable to those reported in
tropical forages by Kabaija and Smith (1988). It is likely
that some bacteria remain in the bags after washing. The
quantities of minerals introduced through such contamination
has not been estimated for the trace elements, although Rooke
et al (1983) did so for macro-elements. They did not, however,
show how much of the introduced minerals were likely to be
subsequently removed by washing of the bags after incubation.
386
Table 4. Mineral disappearance (%) from the feedstuffs
incubated in sacco in ox rumen.
K Na Ca Mg Fe Mn Zn Cu
Wheat straw 81 80 22 67 35 49 32 54
Oats straw 84 73 28 83 39 52 19 62
Barley straw 68 87 36 79 35 49 41 49
Teff straw 72 86 29 68 39 32 25 51
Maize stover 63 91 37 84 31 44 34 68
Coffee pulp 77 72 60 75 39 43 41 51
Wheat bran 89 88 51 77 58 56 35 81
Sorghum bran 83 85 49 72 50 39 40 62
Noug cake 93 81 81 84 32 21 60 63
Cottonseed cake 97 92 93 82 35 45 46 39
Linseed cake 91 89 88 75 28 52 28 46
Groundnut cake 96 85 85 68 44 33 32 56
Sunflower cake 91 81 81 77 41 46 49 54
Cage layer excreta 83 67 67 79 19 29 31 49
Broiler litter 83 73 52 81 37 22 23 55
Results of the digestibilities of minerals in the hay
and straws studied (Table 5) closely resembled those obtained
with the in sacco study. High values were obtained for K, Na
and Mg and low values for most micro-elements. Much of the
minerals in the test diets were mainly from the hay or the
straws except in the case of Cu where molasses may have
contributed considerable quantities. Minerals such as K and Na
whose residual content in faecal fibre was low, had high
apparent availability while those such as Ca and Mg and all the
micro-elements whose faecal fibre content was high had low-to-
medium (<50%) apparent availabilities. Kabaija (1985) reported
increased mineral secretion as the dietary NDF level was
increased from 155 to 600 g/kg in the diets of sheep. Given
the fact that most crop residues are marginal-to-deficient in
several essential elements and that they contain high fibre
387
which may lower utilisation of the minerals, it would be
necessary to pay close attention to the mineral balance of
ruminant diets based on fibrous crop residues whose utilisation
may have been improved through chemical treatment of NPN
suppl ementat i on .
388
Table5.Minerald gestibi itynsheepf dlowqualiroughagessp y dwithmolasses-
ureamixture(dry-matterbasis).
Roughages
NaEM
(g/kg)
Fe
MnZ (mg/kg)
Eu
Meadowh ydiet
Eietarym ner lcontent
Faecalminercontent
Apparentavail bility(%)
Faecalfibremine alcontent(mg/kg)
Teffstrawdiet
Eietarym ner lcon ent
Faecalmineracontent
Apparentavail bility(%)
Faecalfibrem ne alcontent(mg/kg)68
AO 23 50 15
15.0 55.5
S
32.5
55 36 50
31.1
AO 19
140 664 -24 908
46.6
116 19
1009 3044 26 1976 198 523 15
2.1 3.7
54 1100
1.3 2.2
46
5.9 11.3
50 7000
4.2 9.1
90
2.0 0.9
88 30
1.3 0.9
77
21.0 2.6
90 !E
19.4 3.6
94
220000
500
447
100
53
11
Wheatstrawdie
Eietarym neralcon ent
Faecalmineralcontent
Apparentavail bility(%)
Faecalfibrem ne alcontent(mg/kg)532041 0
E.5 15 55
23.1
E 29
23.3 36.5
45
255 4E 00
1.2 2.0
00
3.6 8.1
21
1.9 2.2
60
22.8 8.6
87
600
002
90
9
11
CO
REFERENCES
ARC (Agricultural Research Council). 1980. The nutrient
requirements of ruminant livestock. 2nd ed. Commonwealth
Agricultural Bureau, Farnham Royal, U.K.
Chemlab. Instrument Ltd. 1980. Continuous flow analysis method
sheet No. CW2-075-01, Hornchurch Essex.
Cianci, D. and Hashi, A. 1985. A strategy for animal
production improvement in African countries. World
Review of Animal Production 21: 77-79.
Couch, J.R. 1976. Brewers dried grains as an ingredient in
formula feeds. Feedstuffs 48 (50): 11-12.
Goering, H.K. and Van Soest, P.J. 1970. Forage fibre analysis
(apparatus, reagents, procedures and some applications).
USDA Agriculture Handbook No. 379, U.S. Dep't of
Agriculture, Washington, D.C.
Kabaija, E. 1985. Factors influencing mineral content and
utilisation in tropical forages by ruminants. PhD
thesis, University of Ife, He Ife, Nigeria.
Kabaija, E. and Smith, O.B. The effect of age of regrowth on
content and release of manganese, iron, zinc and copper
from four tropical forages incubated in-sacco in rumen
of sheep. Animal Feed Science and Technology (accepted
for publication).
Kemp, A. 1960. Hypomagnesaemia in milking cows: the response
of serum magnesium to alterations in herbage composition
resulting from potash and nitrogen dressings on pasture.
Netherlands Journal of Agricultural Science 8: 281-304.
Leuker, C.E. and Lofgreen, G.P. 1961. Effects of intake and
calcium to phosphorus ratio on absorption of these
elements by sheep. Journal of Nutrition 74: 233-238.
390
Little, D.A. 1980. Observations on the phosphorus requirement
of cattle for growth. Research in Veterinary Science 28:
258- 260.
Little, D.A. 1984. The dietary mineral requirements of
ruminants: implications for the utilisation of tropical
fibrous agricultural residues. In: P.T. Doyle (ed). The
utilisation of fibrous agricultural residues as animal
feeds. Proceedings of the Third Annual Workshop of the
Australian-Asian Fibrous Agricultural Residues Research
Network held in Peradeniya, Sri Lanka, 17-22 April 1983.
IDP, Canberra, Australia. pp. 34-43.
Little, D.A. 1987. The influence of sodium supplementation on
the voluntary intake and digestibility of low-sodium
Setaria sphacelata cv Nandi by cattle. Journal of
Agricultural Science, Cambridge 108: 231-236.
McDowell, L.R. 1985. Nutrition of grazing ruminants in warm
climates. Animal Feeding and Nutrition (Monograph).
Academic Press, Inc., London, U.K.
McDowell, L.R.; Houser, R.H. and Fick, K.R. 1978. Iron, zinc
and manganese in ruminant nutrition. In: J.H. Conrad and
L.R. McDowell (editors), Latin American symposium on
mineral nutrition research with grazing ruminants.
University of Florida, Gainesville, Florida, USA. pp.
108-116.
Metson, A. J.; Saunders, W.M.H.; Collie, T.W. and Graham, V.W.
1966. Chemical composition of pastures in relation to
grass tetany in beef breeding cows. New Zealand Journal
of Agricultural Research 9: 410-436.
Morris, J.G. 1980. Assessment of sodium requirements of
grazing beef cattle: a review. Journal of Animal Science
50:145-152.
391
Naga, A.M. 1986. Required minerals for the improvement of poor
quality roughages. In: T.R. Preston and M.Y. Nuwanyakpa
(editors). Towards optimal feeding of agricultural by
products to livestock in Africa. Proceedings of a
workshop held at the University of Alexandria, Egypt,
October 1985. ILCA, Addis Ababa, Ethiopia. pp. 68-71.
NAS (National Academy of Sciences). 1971. The atlas of
nutritional data, United States and Canadian feeds. NAS,
Washington, D.C.
NRC (National Research Council). 1978. Nutrient requirements
of domestic animals, No. 3. Nutrient requirements of
dairy cattle. 5th ed. National Academy of Sciences,
Washington, D.C.
NAS (National Academy of Sciences). 1984. Nutrient
requirements of beef cattle. 6th rev. ed, National
Academy Press, Washington, D.C. 90 pp.
NAS (National Academy of Sciences). 1985. Nutrient
requirements of sheep. 6th rev. ed. National Academy
Press, Washington, D.C. 99 pp.
Perkin, E. 1982. Analytical methods for atomic absorption
spectrophotometry. Perkin Elmer, Norwalk, Connecticut,
U.S.A.
Rooke, J. A.; Akinsoyinu, A.W. and Armstrong, D.G. 1983. The
release of mineral elements from grass silages incubated
in sacco in the rumens of Jersey cattle. Grass and
Forage Science 38: 311-316.
Samokhin, V.T. 1981. Methods of controlling the adequacy of
the mineral diet of farm animals. In: V.I. Georgievski i ;
B.N. Annenkov and V.I. Samokhin (editors), Mineral
nutrition of animals. Butterworths, London, U.K. pp.
433-466.
392
Smith, O.B. and Kabaija, E. 1985. Effect of high dietary
calcium and wide calcium-phosphorus ratios in broiler
diets. Poultry Science 64: 1713-1720.
Standish, J.F.; Ammerman, C.B.; Palmer, A.Z. and Simpson, C.F.
1971. Influence of dietary iron and phosphorus on
performance, tissue mineral composition and mineral
absorption in steers. Journal of Animal Science 33:
171-178.
Underwood, E.J. 1977. Trace elements in human and animal
nutrition. Academic Press, New York.
Underwood, E.J. 1981. The mineral nutrition of livestock. 2nd
ed. Commonwealth Agricultural Bureau, London.
393
THE PRESERVATION OF BANANA CROP RESIDUES
THROUGH ENSILING PROCESS
N. H. Sheikh
Department of Animal Production
Faculty of Agriculture, Somali National University
P.O. Box 801, Mogadishu, Somalia
ABSTRACT
A study to assess the susceptibility of banana crop residues
(stems and leaves) to ensiling was undertaken in order to
utilize this material during the dry season when feed is in
short supply.
Four treatments of ensiling banana crop residues were
examined: direct-cut silage (material with 90% of moisture);
direct-cut silage treated with sugar-cane molasses at a rate of
5% of fresh weight; wilted (material with less than 70% of
moisture); wilted and treated with molasses (5% of fresh
weight) .
The chemical composition of banana crop residues has shown
material high in moisture content and low in water-soluble
carbohydrate is not suitable to be ensiled without treatment
prior to ensiling. Wilting to more than 30% DM and the
addition of molasses gave a satisfactorily ensiled product.
INTRODUCTION
In many tropical countries like Somalia, the main constraint
aside from water is the lack of sufficient feed during the dry
season. This fact hinders the development of the livestock
sector in Somalia and makes the settlement of the nomads almost
impossible.
Substantial amounts of agricultural by-products, such as
banana and sugar-cane, are produced annually in Somalia.
However, this forage is presently underutilized. The potential
for by-product feeding in Somalia is great and its efficient
394
utilization can contribute in large degree to the development
of the Somalia livestock industry.
Fresh banana crop residues are already used as animal feed
in some tropical countries (Johri and Shrivastava, 1967).
However, a large portion of these crop residues are lost each
year as a result of poor conservation methods.
The objective of this study was to determine the
possibility of ensiling banana crop residues with or without
additives in order to increase its utilization as animal feed
throughout the year.
MATERIALS AND METHODS
The banana crop residues used in this study were harvested from
two year-old plants of the "Poyo" variety after the fruit was
harvested. The plants were in good vegetative condition, under
normal management practicies for production of banana fruits.
The distance between rows and plants was 2 x 4 m, giving a
plant density of 5000 per hectare. Before the material for
ensiling was collected, representative samples of banana crop
residues were taken to estimate the total mass of this material
per unit area. About 50 plants were randomly removed. The whole
plant as well as stems and leaves were weighed separately. The
latter was done to determine the ratio between the two
components. These operations were conducted in the field with a
portable balance.
Since direct-cut banana crop residue has a very high
moisture content (80-90%), it was proposed to evaluate the
suitability of this material for ensiling alone as well as
treated with additives. Molasses was used as an additive in
this study, because it is a good source of soluble carbohydrate
and is available in large quantities as a by-product of the
sugar-cane industry, usually close to banana plantations.
The following four treatments were applied in this study:
1. Direct-cut silage (high moisture material 80-90%).
395
2. Direct-cut silage treated with sugar-cane molasses
(5% of fresh weight).
3. Wilted silage (more than 30% of DM).
4. Wilted silage treated with molasses (5% of fresh weight).
Initially the whole banana crop residues were cut manually
and chopped into lengths of 2 cm or less in order to obtain
well-packed material. The chopped materials of Treatments 3 and
4 were wilted prior to ensiling by laying them in the sun for
about 8 hours until the moisture content was reduced to below
70%.
Four micro-silos each having a capacity of 100 kg of wet
chopped material were uniformly filled with banana crop
residues. The filling was done in layers, with each layer being
tightly packed to reduce air space. During the packing
operation molasses was uniformly spread on each layer of
Treatments 2 and 4 at a rate of 5% on fresh weight basis.
All four silos were opened after 45 days, and a 2 kg
sample from each silo was drawn for proximate analysis (AOAC
1974) and determination of pH. In addition other visual and
olfactory tests such as colour and presence or absence of
mould, and tests of acceptability to goats, were made.
RESULTS AND DISCUSSION
The average weight of the whole banana plants after removal of
the bunch was 28 kg, while the average weights of stems and
leaves were 22.6 kg and 5.9 kg respectively, giving a ratio
between them of 4:1, confirming the good vegetative condition
of the plants and the excellent variety used in this study.
The total mass of crop residues per unit area is about 890
t/ha/year of fresh weight (around 89 t of DM/ha/year). Total
area of banana plantations in production in Somalia is 4700 ha
implying a potential annual yield of forage available for
livestock use of over 4 million tons.
*
Source: Somali Fruit Company, 1986.
396
The chemical compositions of banana stems and leaves are
presented in Table 1, for material in this study and that of
Johri and Shrivastava (1967). The data from the present study
illustrate the high moisture content in both banana stems and
leaves, particularly the former. Crude protein and ether
extract were higher in leaves, while crude fibre and N-free
extract were similar in both fraction. These data indicate that
banana stems are less nutritious than leaves. The nutrient
content of banana leaves indicates that this forage is much
better than many tropical forages found in Somalia (Yanelli,
1984).
Table 1. Chemical composition of banana stems and leaves on a
dry-matter basis (%) in this study and in that of
John" and Shrivastava (1967).
Stems Leaves
83.58
8.50 (12.2)
3.55 (8.1)
31.20 (25.0)
43.70 (38.9)
13.00 (15.8)
1.04 (1.78)
0.19 (0.14)
The analyses from the four treatments, before and after
ensiling are given in Table 2, and pH and other visual and
olfactory evaluation such as colour, odour, and absence or
presence of mould are given in Table 3.
Moisture X 92.08
on dry-matter basis
Crude protein X 2.70 (2.4)
Ether extract X 0.85 (2.3)
Crude fiber X 30.05 (20.5)
N-free extract X 46.60 (60.5)
Ash X 19.80 (14.3)
Calcium X 1.35 (1.16)
Phosphorus X 0.44 (0.22)
397
T3
II
E "
c
1O w
In 01
v i-
c o
a .q
o
C .O
a
c I.
a »>
.O **
12- r
o
VI i/>
o 01
o >
E
o
01
u c
TJ • '-—, c —'
a "-
u *-* r112
u> 01
b P
III 01 /^
-C *j IM
o V) v^
ai
JO
(A O o o o O ~t o
01 ^> fo *t iM •o m ■^ «-
T>
VI CM
o■ IM I\J oVI *-* m *— T—
01 <a c\j >* CV1*-*
o o o o O o r- o—*
B ^^ CO CO ro in <o N- o.■-
3
x:
»—
ro o CO CO CO <^- o
4-*
v^ »- in ■12■
01
C 3
0)
E
O w
L. «-
o o m o in ro «-
o> m »- oo <o s •-
in CM CM r^
ro (M
cvi o
o in o o in ro r-^% CO 00 CM o «— *— ■—«—
•J■ •o C0 iM O
VI
01
V)
•* «1"
CVJ
o m O in o in o
(A /■* vO CO in in ~» in o
CD INI • • • • • • •*■* >* «— w— c\J o> t\I o
O K) •* ■12
E
in in in m o •o o
£ ^x CO o o> K ^r >o «—
*J
s*' ro w— CO •* «— *— o■—
INI3 ■— in
in in o o in 60 o
in »- in in 4 M «-
•^ cm m o oo cm o
in o o in o cm >o
K «- N- eo *> K* «-
m cm «- •- co cm o
po >t «-
X X X X X X X
r 4-' o■•— o a
0) CO L. i_*^ l_ 01 *■'
o *> n X(_ X 1•— 0)
a 0> »*-
0)
01 l— 01 01•o
V 13 l_
3 n D H- .C
at- *-* l_ 1 i>>
oO HI o Z <
398
Table 3. Physical and chemical characteristics of ensiled
banana crop residues after 45 days.
Treatment
Direct-cut Wilted
Direct-cut with molasses Wilted with molasses
Dark brown
Colour Dark brown Dark brown Almost Light brown
Odour Unpleasant Unpleasant unpleasant Pleasant
Dry matter (%) 12.95 11.03 32.80 31.46
pH 5.8 5.4 6.1 4.1
Mould growth Yes Yes Yes No
From visual observation the colour in Treatments 1, 2,
and 3 were dark brown with unpleasant odour, probably due to
the accumulation of butyric acid. The dark colour intransified
following contact with air direct-cut silage was found to be
unsuitable for ensiling because of its high moisture content
and low content of soluble carbohydrate. For that reason the
reduction of moisture and the addition of molasses could be
considered an appropriate intervention to obtain a successful
ens i ling.
The pH of Treatments 1, 2 and 3 remained relatively high
(5.8; 5.4; 6.1 respectively). The colour of Treatment 4 (wilted
silage and treated with molasses) was light brown in colour
with a pleasant odour of lactic acid. No visible mould growth
was observed and the pH was lower (4.1).
399
When the ensiled materials were offered to goats ad
I ibi tum they refused to eat the silage from Treatments 1 and 2
where secondary fermentation was marked (unpleasant odour), but
the materials from Treatments 3 and 4 were consumed.
CONCLUSION
There are large quantities of banana crop residues available in
Somalia with substantial potential for contributing to its
livestock industry. Even though this by-product alone is a poor
quality feed, it becomes extremely important for maintenance
purposes during the dry season when little or no grass is
avai I able.
From this experiment it was concluded that banana crop
residues are likely to ferment successfully when the moisture
content is reduced to below 70% prior to ensiling and a
fermentable carbohydrate source such as molasses is added.
REFERENCES
AOAC (Association of Official Analytical Chemists). 1974.
Official methods of analysis. AOAC, Washington, D.C.
Bolsen, K.K, Ilg, H.J. and Axe, D.E. 1980. Additives for corn
silage. J. Animal Sci. 51. Suppl. 1:230.
John", P.N. and Shrivastava, J. P. 1967. Indian Vet. J. 44: 425.
Yanelli, P. 1984. The principles of pasture improvement and
range management and their application in Somalia. FAO,
Rome.
400
SOLUTIONS TO THE PRACTICAL PROBLEMS OF FEEDING
COCOA-PODS TO RUMINANTS
O.B. Smith
Department of Animal Science
Obafemi Awolowo University
lIe - Ife, Nigeria
ABSTRACT
Data is presented showing that cocoa-pods, a by-product of
cocoa processing could be used as a ruminant feed. The
widespread nature of cocoa-processing sites which makes it
difficult and expensive to collect and transport the cocoa-pods
to sites of utilisation, and the need to grind the pods prior
to feeding are identified as the main physical constraints
while the high cell wall and low cell content of the material
constitute the main nutritional constraints to its effective
uti I i sat ion.
One way of overcoming part of the physical constraint is
to develop technologies that would permit the use of the pods
at the main sites of production. Chemical treatment using ash
solutions of crop residues, ensiling the material with poultry
manure or urea, and strategic supplementation with fermentable
nitrogen and good quality forages are suggested as strategies
to overcome the nutritional constraints to the utilisation of
cocoa-pods as a ruminant feed.
INTRODUCTION
The competition between man and his animals for food such as
cereals, pulses and oil seeds is partly responsible for the
ever- increasing livestock feed costs. In developing countries,
the production of these feed items is too low to meet demands,
and as in all such situations, where demand exceeds supply, the
cost of these items has continuously soared. Research efforts
have therefore been directed towards finding alternative
401
sources of nutrients for livestock, using materials that cannot
be directly consumed by man. This approach may alleviate man-
animal competition and reduce animal feed costs particularly
for ruminants which can utilise fibrous crop residues and by
products of cereals, pulses and oil seed processing.
Enormous quantities of these materials which are usually
not eaten by man, are produced annually on the farm after crop
harvesting and in the food processing industry (Table 1). Many
of these materials are currently being evaluated on a worldwide
basis in order to determine their suitability as livestock
feeds. Cocoa-pod produced after the removal of the cocoa beans
from the fruit, is one such crop residue being evaluated in
Nigeria as a potential feed for ruminants. The pod forms about
75 - 80% of the weight of the fruit, and from estimates of
cocoa production in Nigeria, about 1 million tonnes of dried
pod could be available annually on Nigerian cocoa plantations
for feeding ruminants.
Table 1. Available quantities of major crop residues in
Africa.
Residue
Crop Type Quantity
('000 tonnes)
Maize Stover 62,000
Sorghum Stover 48,600
Rice Straw 9,300
Sugar-cane Tops 17,070
Groundnut Haulms 8,200
Husk 1,250
Cocoa Pods 9,710
Banana / plantain Leaves 15,020
Pseudo stems 32,700
Cassava Tops 45,000
402
According to published values, the dried pod may
contain about 6-10% crude protein, 24-42% crude fibre, 49-61%
nitrogen-free extracts, 9 - 16X ash, made up primarily of
potassium salts (Owusu-Domfeh, 1972; Gohl, 1975; Devendra,
1977; Otchere et al, 1983; Smith and Adegobola, 1985). This
nutrient profile is similar to that of many tropical grasses
(Ademosun and Kolade, 1973). The material therefore has good
potential as a feed ingredient particularly for ruminants.
This report presents results obtained to date, at the
Obafemi Awolowo University, Ile-Ife, Nigeria, to develop a
feeding strategy using cocoa-pod in ruminant diets, followed by
a discussion of identified constraints and suggested solutions
to its efficient utilisation.
Preliminary experimental studies
Three cattle growth trials and two digestion studies (cattle
and sheep) constituted the first series of experiments. In the
cattle growth trials, local cattle (Keteku, N'Dama and Muturu)
found mainly in the cocoa-growing areas of Nigeria were used as
experimental animals. Using standard experimental procedures,
the animals were allocated into control and test groups, and
fed their respective diets for periods of 98 to 112 days. The
control and test diets as shown in Table 2 were maize or
guinea-maize based, and were similar, except that the cereals
were replaced in graded amounts with cocoa-pod at 20, 30, 40,
50 and 60%.
For the sheep digestion studies, the total collection
method was used, while the indicator method, using acid-
insoluble ash as an internal maker, was used for the cattle
study. The digestibility of diets containing 0, 15, 30, 45, 60
and 75% pod (sheep) and 0, 20, 40% pod (cattle) were
determined. Cocoa-pod digestibility in sheep where six levels
of the material were used was determined by extrapolation.
403
0)
O
O
+-*
1I
**-
o
8
jQ
HS1
Cv
I
ro ][
s -
u
£ 18
at u>
i- a
o> CM •* in in o ro c\J
a S •* o ro "~ o o
o o o o o CO m in C\1
s oin m CO m o o o o
o in in in o in ro rj• I • • • I ■ I ■ i ••
SO •» O fO «- o o
■* >o in
Si • ** o
■* o 4 n n
ro »- o o o
>* ro m r- o rO M C\I
o o o
•O K h- 4 K1 N
Q! £ :=
r^ r- **
•^ >* c>
O fO CM
o o o
8. is 15
.C CO T) w
a> o a) lo
l_ o — 0)
O O I. £
i/> u Q 5
a■s.
iI
i 9
ia c —
£ 3
404
Growing cattle consumed cocoa-pod diets as much as they
did the control diets even at the highest level of inclusion
(60X) (Table 3). Pod dry-matter intake averaged 2.4X of body
weight, while total dry-matter intake was about 3 to 4% of body
weight.
Table 3. Cattle response to grain substitution with cocoa-pod.
First trial
Diets
Second trial
Parameters Control 20% 40% Control 30% 50% 60%
Dry-matter intake
1 pod pod 2 pod pod pod
(kg/day)
- Cocoa-pod - 1.4 3.2 - 1.7 2.3 3.3
- total feed 5.2 5.5 5.6 5.3 5.2 4.6 5.6
Growth rate
(kg/day) 0.8 0.6 0.5 0.7 0.6 0.4 0.2
Feed / gain 6.5 9.2 11.2 7.6 8.7 11.5 28.0
There was a negative correlation between level of dietary
pod and growth rate and efficiency of utilization parameters
(Figure 1). Thus, growth rate declined and feed conversion
became less efficient as dietary pod level increased. A
405
regression of dietary pod level on growth rate gave the
following equation, Y ■ 0.82 - 0.009X, with an r value of -0.97
where Y = growth rate and X = dietary pod level. A similar
trend of decreasing dry-matter digestibility with increasing
dietary pod level, mainly due to the low digestibility of pod
dry-matter (23%) is indicated in Table 4.
Table 4: Digestibility of cocoa-pod based diets by ruminants (%).
% di etarv cocoa-
0
Dod (cattle) %
15
dietary cocoa-pod (sheep)
Nutrients 20 40 0 30 45 60 75 1001
Dry-matter 76.9 62.3 58.6 19.7 76.7 66.1 53.1 50.0 35.8 22.7
Organic matter - - 80.6 78.0 67.6 54.0 49.0 36.5 22.9
Crude protein 73.0 62.7 57.2 73.2 72.3 70.4 60.9 61.6 56.8 50.8
Acid-detergent fibre 53.8 38.7 35.2 - -  
By extrapolation.
At the end of these first series of experiments, it was
possible to identify a number of constraints that might reduce
the effective utilisation of cocoa-pod as a feed ingredient, or
make the adoption of feeding strategies built around cocoa-pod
difficult. These constraints can be described as being
physical or nutritional.
Strategies for eliminating physical constraints
As indicated earlier, about one million tonnes of cocoa-pods
are generated annually on Nigerian cocoa plantations. It is
406
difficult to assess what amount is available for animal
feeding. Most of the available pod is annually wasted because
cocoa-growing and processing is to a large extent carried out
by individual smallholders scattered all over the cocoa-
producing area. Many of the farms are not easily accessible,
and when accessible may not produce enough pods to encourage
setting up a collection service. The lack of easily accessible
processing centres in areas where large amounts of pod can be
collected is one of the major constraints to the utilization of
pod as animal feed.
Smith (1984) indicated that transportation costs for
collecting pods from sites of production to the site of
utilisation accounted for 78% of the total cost of producing a
tonne of dried pod for feeding. The farther apart the
production sites are from each other and from the sites of
utilisation, the higher the transportation costs, and the less
attractive the use of pod will become.
If it were possible to centralise cocoa processing, a
large part of the constraint of collection and transportation
could be overcome. This, however, does not appear feasible. A
more practical solution would be to use the pod at or near the
site of production. The major target users would therefore
have to be the cocoa farmer or his neighbour keeping a few
goats and sheep. On the other hand feed manufacturers who may
want to use the material in compounded ruminant diets or as an
energy diluent in pellets or finishing swine feeds may contract
cocoa farmers to supply dried pods once or twice a year, much
as maize growers now supply maize to feed manufacturers.
407
Figure 1. Correlation between level of dietary pod and growth
rate.
Growth rate
(Kg/day)
1.0 r-
0.8
0.6
0.4
0.2
0 10 20 30 40 50 60
Dietary level of cocoa — pod (%)
408
Cocoa-pod has to be processed before being fed to
livestock. Processing requirements are minimal, but may still
constitute a constraint in the rural setting. The material
contains up to 75% moisture and may have to be dried before
feeding. However, drying may not constitute any constraint,
since the major cocoa harvesting period coincides with the dry
season, and the pods can easily be sun-dried. After drying, it
has to be reduced to appropriate particle sizes for livestock
by grinding.
Three different types of hammermi I Is have been used to
reduce the particle size and these have proved suitable.
Grinding, where it requires electricity, may constitute another
constraint in a village setting. Nevertheless, when properly
dried, cocoa -pod is very brittle, and can be easily broken up
into small particles by trampling. It is possible to reduce
particles to sizes small enough to feed with other ingredients.
On the farm, trials need to be carried out to evaluate this in
terms of acceptability to both the farmer and the animal.
Strategies for eliminating nutritional constraints
The generally low nutritional value of cocoa-pod is a major
constraint to its being used efficiently as animal feed. It is
low in protein (6%) and high in cell wall components (57% ADF,
66% NDF and 24% lignin) (Smith et al, 1987). This poor
nutrient profile accounts for its low rumen degradabi lity (T1/2
■ 288 hr) and overall poor digestibility, and may constitute a
constraint to optimally utilising the material as a feed
ingredient. Two proven strategies are suggested as remedies to
409
this nutritional constraint - chemical treatment and
supplementation.
Alkaline treatment of cocoa-pod
Chemical treatments of fibrous crop residues, similar in
composition and nutritive value to cocoa-pods, .have reportedly
improved their utilisation to such an extent as to make their
utilisation as feed ingredients feasible and profitable
(Jackson, 1977; Doyle et al, 1986). None of the proven
chemicals such as sodium hydroxide, calcium hydroxide,
potassium hydroxide and ammonia are suitable for our target
users because of the high cost and scarcity of the chemicals
and hazards associated with their use. A suitable alternative
which, under limited testing, appears as effective as sodium
hydroxide is the caustic ash solution of some crop residues.
Cocoa-pod ash, for example, contains about 44 mg of potassium
per kg, and according to Adebowale (1985) the ash solution
contains about 21 and 29% OH ions in the form of NaOH and KOH
respectively.
This property was effectively exploited by Smith et al
(1987) who used different concentrations of cocoa-pod ash
solutions as a chemical to treat cocoa-pod in an attempt to
improve its feed value. As shown on Table 5, a linear increase
in the rumen degradabi I ity of cocoa-pod treated with its own
ash solutions of increasing concentration was observed. More
significantly, the improvement in rumen degradabi lity obtained
by cocoa-pod ash solution treatment was similar to that
obtained by using NaOH solutions of equivalent alkalinity. The
410
authors also reported that treated cocoa-pod-based diets were
better digested by both goats and sheep than untreated pod-
based diets (Table 6).
Table 5. Rumen degradabi lity of treated cocoa-pod.
% NaOH solution % pod ash solution
Nutrients
8 2 4 6 8
Dry matter 34.8 41.1 47.6 52.6|37.2 46.3 54.8 55.4
Acid-detergent fibre 24.6 33.8 38.6 42.5(26.7 35.9 44.2 46.6
Neutral -detergent
fibre 15.0 25.9 35.7 36-5(15.3 29.8 44.7 41.7
Table 6. Digestibility of treated cocoa-pod by goats and sheep (%)
Sheep Goats
Control diet Test Control Test
diet diet diet
Dry matter 45.2 54.5 46.3 59.8
Acid-detergent fibre 12.4 30.7 31.0 36.2
Neutral-detergent fibre 15.6 39.5 37.9 40.2
Control diets contained 50% untreated cocoa-pod, while
test diets contained 50% treated cocoa-pod. Other
ingredients are as shown on Table 2. (50% cocoa-pod diet).
411
This treatment method has the potential to remove a
major constraint to the efficient utilisation of cocoa-pod as a
livestock feed. The technology should be attractive to cocoa-
farmers who generate cocoa-pod on their farms. The technology
involved is simple, and the farmers are used to handling the
ash which is used locally as a base for soap manufacture.
Another treatment method which may improve the feed value of
pod, is ensiling pod with poultry manure or urea. Both manure
and urea would liberate ammonia which has been shown to
effectively improve the utilisation of fibrous residues through
ammoniation of cell walls (Doyle et al, 1986). We have,
however, not evaluated this technique.
Forage supplementation
A second strategy suggested for eliminating the nutritional
constraint associated with the feeding of cocoa-pod is that of
supplementation with suitable forage to enhance rumen function.
According to Preston and Leng (1981) supplementation of crop
residue based diets with fermentable nitrogen and forages will
ensure an adequate rumen ecosystem that will improve the
utilisation of the residue.
Tables 7 and 8 show the results of two forage
supplementation studies that were carried out in sheep and
cattle.
412
Table 7. Effect of forage supplementation of cocoa -pod- based
diet on nutrient digestibility by sheep.
Item Control sheep Test sheep
Feed intake (gDm/day)
Basal diet
Centrosema
Total
735.0 645.0
19.0
735.0(80g/kg W0,75) 664.0<70g/kg W0,75)
Digestibi lity <%)
Dry matter 57.0
Organic matter 59.6
Crude fibre 34.0
T1/2 of dry matter (hrs) 288.0
60.0
61.0
37.0
182.0
Both control and test sheep were fed a 50% cocoa-pod-based
diet. Test sheep were offered freshly cut Centrosema daily.
413
Table 8. Response of cattle fed on cocoa pod-based diets to
G I i r i c i d i a supplementation.
,
Item Control cattle Test cattle
Feed intake (kg DM/day)
Cocoa-pod 4.6 4.6
G I i r i c i d i a - 0.2
Total 4.6 4.8
Daily gains (kg/day) 0.4 0.4
Feed/gain 11.5 12.0
Control and test cattle fed 50% cocoa-pod-based diet. Test
cattle were offered freshly cut G I i r i c i d i a daily.
In the sheep study, some improvement in the utilisation
of the pod-based diet due to forage supplementation was
obtained, although poor-to-medium quality Centrosema was used,
in order to simulate the quality likely to be available to
target users. Better forage material may therefore further
improve cocoa-pod utilisation. We could not confirm the above
speculation with the cattle study because of poor intake of
G I i r i c i d i a by the test cattle. We conclude, as suggested by
Preston (1982) that for forage supplementation to enhance the
utilisation of crop residues, the forage should be of good
414
and digested. Although we have not experimented with
fermentable nitrogen supplementation of cocoa-pod-based diets,
theoretical considerations suggest that the strategy may
enhance cocoa-pod utilisation.
CONCLUSION
All of the strategies suggested for alleviating the physical
and nutritional constraints to the efficient utilisation of
cocoa-pod in ruminant diets were carefully selected to ensure
that they are within the reach of the target users - the small-
scale farmer. Some of these strategies have been evaluated on
an experimental basis, and results obtained showed that they
have the potential to achieve the set objectives. These, as
well as those yet to be evaluated need to be tested on farm in
order to fully assess their value.
REFERENCES
Adebowale, E.A. 1985. Organic waste ash as possible source of
alkali for animal feed treatment. Anim. Feed Sci.
Technol. 13: 237-248.
Ademosun, A. A. and Kolade, J.O.Y. 1973. Nutritive evaluation
of Nigerian forages. III. A comparison of the chemical
composition and nutritive value of two varieties of
Cynodon. Niger. Agric. J. 10: 160-169.
Devendra, C. 1977. The utilisation of cocoa-pod husk by sheep.
MaI. Agric. J. 51: 179-186.
415
Doyle, P.T; Devendra, C. and Pearse, G.R. 1986. Rice straw as
a feed for ruminant. Australian Government Printing
Services, Canberra.
Jackson, M.G. 1977. Review article: The alkali treatment of
straw. Anim. Feed Sci. Technol. 2: 105 - 130.
Otchere, E.O; Musah, I. A. and Bafi-Yeboah, M. 1983. The
digestibility of cocoa husk based diet fed to sheep.
Trop. Anim. Prod. 8: 33 - 38.
Owusu-Domfeh, K. 1972. The future of cocoa and its by-products
in feeding of livestock. Ghana J. Agric. Sci. 5: 57 -
64.
Preston, T.R. 1982. A strategy for the efficient utilisation
of crop residues and agro- industrial by-products in
animal production based on their nutritional
constraints. In: Crop residues and agro- industrial by
products in animal feeding. Proceedings of the FAO/ILCA
workshop held in Dakar, Senegal, 21-25 September 1982.
FAO Animal Production and Health Paper No. 32. FAO, Rome,
pp. 29-47.
Preston, T.R. and Leng, R.A. 1986. Matching livestock
production systems to available resources. Pretesting
edition. ILCA, Addis Ababa, Ethiopia.
Smith, O.B. 1984. Studies on the feeding value of agro-
industrial by-products for livestock. IV: The economics
and feasibility of feeding cocoa-pods to ruminants.
World Rev. Anim. Prod. 20: 61-66.
416
Smith, O.B. and Adegbola, A. A. 1985. Studies on the feeding
value of agro- industrial by-products for livestock. III.
Digestibility of cocoa-pod and cocoa-pod-based diets by
ruminants. Anim. Feed Sci. Technol. (The Netherlands)
13: 249 - 254.
Smith, O.B; Osafo, E.L.K. and Adegbola, A. A. 1988. Studies on
the feeding value of agro- industrial by-products:
Strategies for improving the utilisation of cocoa-pod-
based diets by ruminants. Anim. Feed Sci. Technol. (The
Netherlands) 20(3): 189-201.
417
COCOA-POD SILAGE AND COCOA-POD GRASS SILAGE
IN GOAT AND SHEEP NUTRITION
F. 0. Olubajo, M.M. Asonibare and
2
E. 0. Awolumate
Department of Animal Science, University of Ibadan
Ibadan, Nigeria
2
Cocoa Research Institute of Nigeria (CRIN), Idi-Ayunre
Ibadan, Nigeria
ABSTRACT
Six digestion trials were conducted with West African Dwarf
bucks and Dwarf rams to study the utilisation of cocoa-pod
silage and of graded levels of cocoa pod - elephant grass
silages consisting of the following treatments : (1) 100%
elephant grass silage (control); (2) 50:50; (3) 25:75; (4)
15:85; (5) 10:90, grass : cocoa-pod (fresh basis),
respectively; and (6) 100% cocoa-pod silage.
The cocoa-pod silage contained approximately 5.7% crude
protein (CP), 22% crude fibre (CF) and a mean energy value of
4.4 kcal/g in contrast to the grass silage with a composition
of 4.8% CP, 32% CF and 4.7 kcal/g of energy.
Results indicated that on metabolic-weight basis more
digestible dry matter (DDM; P<0.01), digestible energy (DE,
P<0.001) cellulose or hemicel lulose was consumed from the
control diet. Intake of digestible nitrogen was also
significantly (P<0.001 )higher for the contol diet than for any
of the silages. More nitrogen (N) was excreted when either
treatment 2 or treatment 3 was fed indicating that the N
content of these treatments was metabolised less efficiently
while N - retention was similar and slightly positive for all
treatments.
Sheep consumed more (P<0.001) DM and energy, and
significantly (P<0.05) higher DM and DE than goat. Both
species were similar in their intake of digestible N. However,
more N (P <0.01) was excreted by sheep showing that this
418
species metabolised the N content of the diets less
efficiently. Nitrogen retention by both species was similar.
Additional sources of protein supplement are required in all
diets for better performance.
INTRODUCTION
Cocoa-pod is a by-product of the cocoa harvesting industry. It
forms about 80% of the cocoa fruit and it is essentially a
waste product except for the negligible amount used in the
manufacture of local soap. Oguntuga (1975) and Awolumate
(1982) have given chemical composition of cocoa -pod while
Adeyanju et al (1975a, b) have reported the use of the dried pod
as a substitute for maize in swine ration, in milk production
of dairy cows and in the maintenance ration of sheep and goat
or at various levels in the starter diets of chicks up to six
weeks of age (Adegbola et al 1977).
The object of this investigation was to study the
nutritive and replacement values of fresh cocoa-pod silage and
cocoa pod - grass silage.
MATERIALS AND METHODS
Silage preparation
The following silage treatments were prepared from fresh cocoa
pods and elephant grass (Pennisetum purpureum) at a fairly
advanced (full flower) stage:
1. 100% elephant grass (Pennisetum purpureum as control)
2. 50% grass + 50% cocoa-pod
3. 25% grass + 75% cocoa-pod
4. 15% grass ♦ 85% cocoa-pod
5. 10% grass ♦ 90% cocoa-pod
6. 100X cocoa-pod
419
For each batch of silage preparation the grass which was
at the fairly advanced stage of growth was cut fresh, chopped
into 2-6 cm lengths. Cocoa-pods were collected immediately the
beans and mucilage were removed from the fruits, chopped into
small bits and both grass and pods were weighed (on wet basis),
thoroughly mixed and made to pass through a chopper and packed
according to the ratio required in double- layered polythene
bags fitted into 198- litre drums. After compressing thoroughly
the content of each drum was sealed, weighted down with about
15-20 cm layer of dry earth and heavy stones and ensiled for
at least 12 weeks before it was fed.
Representative samples were taken from each batch of
fresh mixture for dry-matter determination and proximate
analysis.
Digestion trials
Six animals consisting of three West African Dwarf bucks
weighing between 20.0 and 23.2 kg (mean 21.4 + 1.34 kg) and
three West African Dwarf rams ranging from approximately 18.2
to 32.3 kg (mean 23.5 + 6.26 kg) were used in the digestion
trials.
The digestibility trial of the grass silage (control
diet) consisted of 12 days of preliminary and seven days of
collection periods while each subsequent feeding trial was of
seven days of preliminary and seven days collection duration.
During the digestion trials each experimental animal
housed in a digestibility crate designed for easy collection of
urine, was harnessed with a faeces-collection bag four days
before the commencement of actual collection. Each animal
group was used as its own control and for each of the other
treatment digestion trials.
420
The top 4 - 5 cm layer of silage in each drum was
discarded and representative samples were taken from top to
bottom, cut into small bits and after mixing well, subsamples
were taken for dry-matter and pH determinations and for
chemical analysis. During the first preliminary period each
animal was offered 2.73 kg of the test diet on the first day
and was increased as necessary to allow for ad libitum intake
in subsequent days. During collection period the amount
offered was restricted to about 95% of the mean intake of each
animal during the preliminary period.
Each day's feed was offered between 0800 and 0830 hours
and at 1600 hours. Fresh tap water and salt lick was supplied
ad libitum. Faeces from each animal was collected twice daily
just before the morning and afternoon feeds were offered,
weighed, mixed thoroughly and approximately 20% from morning
and afternoon collections composited and taken to the
laboratory and treated like the samples of feed offered. Orts
from the previous day's feed was collected once daily just
before offering morning feed, weighed, mixed and representative
samples were taken for dry-matter determination. Urine from
each animal was collected and with 10 ml of H-SO, in the last
three days of each collection period. Total volume of urine
excreted by each animal was measured every morning and 10%
aliquot taken and bulked for the three-day period for nitrogen
and energy determination. The urine samples were stored in a
deepfreezer at -5°C until required for analysis.
Analytical procedures
Dry-matter of the silages, faeces, and ort was determined by
drying weighed duplicate samples in a forced air electric oven
at 90°C to constant weight. The pH was determined from
squeezed silage juice samples by means of Radiometer Copenhagen
glass electrode pH meter. Gross energy (GE) of feed and faeces
was determined in a Gallenkamp ballistic bomb calorimeter using
benzoic acid as standard. GE in urine was estimated by drying
421
a known volume soaked in a pre-weighed ashless filter paper
over P-Oc in a desiccator, re-weighed after drying, followed by
bombing. The AOAC (1970) procedures were used for the
determination of the proximate constituents in the feed, faeces
and urine. Acid detergent lignin was estimated according to
Van Soest (1963) and cellulose by the method of Crampton et al
(1960). Statistical analyses were based on factorial design as
described by Steel and Torrie (1960) with the six treatments
serving as the main treatments, the species as subtreatments
and the animals as replicates. Metabol isable energy was
estimated by multiplying digestible energy by a factor of 0.81
(ARC, 1965).
RESULTS
The chemical composition of the pre- ensiled mixtures and of the
resulting silages from them is shown in Table 1 and 2
respectively. The data in Table indicated that the mean dry-
matter (DM) content of the elephant grass at harvest was
slightly below the 30% or above known to result in silage of
good quality. Increased replacement of the grass with fresh
cocoa-pod led to decreased DM content of the pre-ensiled
mixtures due to the high moisture content of the fresh cocoa-
pod. Replacement of the grass with cocoa-pod resulted in an
improvement in the N content of the silages by approximately
23.8% up to the 75% cocoa-pod inclusion and was slightly lower
in the other treatments. Similarly, ensilage of cocoa-pod with
elephant grass led to an increase in the nitrogen-free extract
(NFE) but to a decrease in CF, lignin, and other constituents
of the silages. Addition of cocoa-pod to grass did not improve
fermentation of the grass as there was little or no difference
between the pH values of the grass silage (control) and those
of grass-cocoa pod silages. Ensiling cocoa-pod for a period
of 12 weeks (or longer) showed little or no change.
422
Table 1. The proximate composition of pre-ensi led treatments (%).
Treatment
1
100% grass
2 3
50/50 25/75
4
15/85
5
10/90
6
100%
Dry matter 28.84
Organic matter 85.57
Ash 14.43
Crude protein 7.65
Ether extract 2.35
Crude fibre 34.31
NFE 41.26
Lignin 8.23
Hemicel lulose 25.21
Cellulose 30.90
Energy (kcal/g) 4.730
22.55 19.02
88.01 92.09
11.99 7.91
7.62 7.51
1.95 1.93
31.24 29.28
47.20 53.37
7.60 7.18
21.95 20.76
26.62 26.75
4.786 4.993
18.84 20.99 18.20
91.25 89.16 87.35
8.75 10.84 12.65
7.49 7.59 6.46
1.75 0.94 0.90
28.09 27.16 24.38
53.92 53.47 55.62
7.85 6.44 2.29
18.12 22.03 22.12
24.51 24.78 25.31
4.809 4.977 4.575
Table 2. Proximate composition of the silages (%).
Treatment
1 2 3 4 5 6
100% 50/50 25/75 15/85 10/90 100%
grass cocoa-podi
Dry matter 19.16 16.94 22.22 20.21 18.09 14.56
Organic matter 83.05 85.04 89.70 88.18 86.21 82.52
Ash 16.95 14.94 10.30 11.82 13.79 17.48
Crude protein 4.78 5.92 5.92 5.46 5.69 5.69
Ether extract 2.10 1.55 1.52 1.10 0.77 0.75
Crude fibre 32.21 29.35 27.24 26.10 25.12 22.40
NFE 43.96 48.22 55.02 55.52 54.63 53.68
Lignin 8.21 7.56 7.12 6.80 6.40 5.20
Hemicel lulose 24.10 21.30 19.91 18.7 21.56 21.32
Cel lulose 36.01 28.50 30.00 29.00 28.50 30.50
Energy (kcal/g) 4.714 4.675 4.984 4.592 4.837 4.374
pH 5.35 5.25 5.08 5.10 5.12 7.70
423
Feed and nutrient intake
On metabolic-weight basis (g/ kg W * ) mean daily consumption
of DM and of DDM was significantly (P<0.01) higher for the
control diet than for either the cocoa-pod silage or any of its
combinations with grass (Table 3). The pattern of intake of
digestible cellulose or hemicel lulose was similar to that of
dry-matter intake. The data in Table 3 also indicated that the
mean DE. value of 212 kcal/ kg W ' for the control diet was
significantly (P<0.001) higher than the mean value of 73 kcal/
kg W ' for the cocoa-pod silage. While the energy content of
the grass silage was approximately 73% digestible the
corresponding value for the cocoa-pod silage was approximately
33%.
The significantly (P<0.01) higher intake of dry-matter
from the control diet by the experimental animals could be due
to the intake of significantly higher (P<0.001) digestible
energy from this diet (Table 3) when compared to any of the
silages resulting from its combinations with the cocoa-pod.
Blaxter (1961) have suggested that digestibility is an
important determinant of ad libitum intake of feeds and that
the amount of roughage consumed by sheep fed ad libitum, is
closely related to the energy digestibility of the feed and
that increased energy digestibility leads to increase in dry-
matter intake.
The significantly lower energy and digestible-energy
intake values obtained for the cocoa-pod silage and of the
15:85, and 10:90 grass/cocoa-pod silage was probably due to the
lower energy value and the high moisture content of the cocoa-
pod in these silages. Intake of energy from cocoa-pod silage
which was 76X of the intake from the control diet resulted in
only 34% of the digestible-energy intake of the latter.
424
Table3.Meandailyint keofnutrie ts(g/kg00)byexperim ntalnimals.
00SS
**
5.46
*** 0.12 ** 0.18 *** 0.85 *** 0.12 *** 11.61 *** 15.91 ***
1E.21
S.E 2.37
6
50.9ce
26.7b 2.9b 0.4d 15.5b 3.3* 222C 73C 59b
5
48.8*
19.9b 2.9W
0.6*
13.8C
2.6*
236Cd 101C 82b
tmen
45.6d 22.6b 2.5C 0.5d 13.2C
2.6Cd
209C 101C 82b
4
Trea
57.0D
27.^
3.9a 0.9te E.1b 5.2b 273ab
138b 112b
3
54.9*
S.9b
3.3ab
1.0b 15.6b 5.0b
S7
124b 100b
2
62.7s 48.7s 3.0b 1.4a 22.5a 8.3a 292a 212a 171a
1
Erymatter
Eigestibledrymat er
Erudep otein
Eigestiblecrudep o ein
Eellulose
Hemicellulose
Energy(kcal/W0"75)
E(kcal/00gW°)
ME(")
Nutrient
Valuesinthsamerowfoll wedbylett rarn t
significantlydifferent.
**=P<0.01;*0.001.
Nitrogen utilization
Though there was a significant (P<0.05) improvement of
approximately 13% in the N intake of the 25:75 grass/cocoa-pod
silage over that of the control diet (Table 4), intake of this
nutrient in other silages with higher proportion of cocoa-pod
was depressed. Similarly, substitution of grass w.ith cocoa-pod
did not significantly (P>0.05) depress the digestible N up to
the 75% level of inclusion but significantly depressed
digestible N at (P<0.01) about 75% level. Cocoa-pod contained
the lowest amount of N. The degree of depression rose as the
proportion or level of cocoa-pod increased. Similarly results
of depressed intake of dry-matter and digestible nutrients when
cocoa-pod was substituted for maize in either sheep and goat,
swine or beef cattle rations, have been reported (Adeyanju et
al, 1975a, b; Fraps, 1946; Adeyanju et al, 1977; Bateman et al,
1967; Glover et al, 1958).
426
Table4.Nitrogenutilizationbyshe pandgo t.
***
0.04
0.04N S.
*** 0.2
**
0.00
** 0.04S.E.
be
0.050°°
-
0.46® 0.39® O.OT5 0.02®6
0.555ab
AO
0.44®® 0.00®
0.10b 0.04a
485
t
atmen
0.553®b
O^O**6
0.32ab be
0.08°° 0.00® 384
Tre
0.155®
0.15®C
0.54C
0.39® 0.00®
20
3
0.096®b
0.16®°
0.52C 0.37® 0.55®
31
2
0.48®b
0.155®1
0.26b
0.22® 0.10® 45
NIntake<g/kWU"^)
•iij
ii% ii\ ii\
Xofabsorption
Output
FaecalN( UrineN(
AbsorbedN( Nretained(
Retentionas
Valuesinthsamerowfol wedbylett rscriptanot
significantlyd fferent.
**=P<0.01;*<0.01.
Nitrogen retention was positive, low and similar
(P>0.05) for all treatments studied. Approximately 45% of N
absorbed and 21% of N consumed was retained by the experimental
animals when fed the control diet while the corresponding
values for cocoa-pod silage were approximately 29% and 4%
respectively. The relatively low N utilization from cocoa-pod
silage of from any of its silage combinations could not be
attributed to its concentration either in the pre-ensiled
mixtures or in the resulting silages.
Sheep consumed more (P<0.001) dry-matter, nitrogen and
energy and higher energy (P<0.05) than goat. Both species were
similar in their intake of digestible N.
DISCUSSION
The low dry-matter (DM) content obtained for elephant grass is
in agreement with the results of other workers elsewhere which
have consistently shown that at between 4 and 8 weeks of
regrowth the DM content of elephant grass is below 20% and at
24 weeks, when in full bloom, a mean of 36.7% was obtained in
the humid zone of south-western Nigeria (Oyenuga, 1957; Olubajo
and Oyenuga, 1974; Olubajo, 1981). The depressed dry-matter
content of the pre-ensiled grass-cocoa-pod mixtures was as a
result of the high moisture content of the cocoa-pod when
compared to that of elephant grass (control), while cocoa-pod
replacement led to an increase in nitrogen-free extract as a
result of the higher content of this nutrient in the cocoa-pod.
The slight decrease in the crude protein content of the ensiled
products may be attributed to loss of volatile nitrogen
products (such as ammonia) from protein fermentation. The high
pH values of the silages are attributable to the limited
available soluble carbohydrates in the ensiled mixtures as well
428
as to the high ash content (alkal i -forming cations Ca , K and
Na ) in the pre-ensiled mass most especially in the 100% cocoa-
pod which may have inhibited or lowered the activities of acid-
forming lactobacilli thereby limiting the level of lactic acid
production in the ensiled mass.
The relatively low N utilization of cocoa-pod silage or
of any of its grass silage combinations could not be attributed
to its concentration either in the pre-ensiled mixtures or in
the silages when compared with that of the control diet as its
concentration was similar in all the treatments. It could
however, be due to the presence of as yet unidentified
inhibitors in the cocoa-pod. Awolumat (1982) was of the
opinion that pesticides used in plant protection, tannins,
theobromine and polyphenols if present in cocoa-pod can affect
the voluntary intake, digestion and metabolism in animals.
They also decrease palatability and digestibility of protein.
Chlorogenic acid present in cocoa components is found to cause
motor activity in ruminants and rats affecting decreased weight
and feed conversion efficiency. This may account for the low
values obtained for the cocoa-pod diets. The similarity in the
digestible nitrogen and digestible dry-matter intake by sheep
and goat obtained in the present study confirms similar reports
by Adeyanju et al (1976), while the report of Burroughs et al
(1950) showed that sheep utilized crude protein in cocoa-pod
rations better than goat. They also reported higher apparent
digestibilities of all feed nutrients studied, by sheep.
However, more nitrogen (P<0.01) was excreted by sheep in
the present investigation, showing that sheep metabolised N
content of the diets less efficiently. Nitrogen retention by
both species was similar (P<0.05).
429
Though the period for each digestion trial was too short
for any meaningful appraisal of the effect of the various diets
on the live weight changes of the experimental animals, the
limited data obtained during the experimental period indicated
that despite the slight positive nitrogen retention by each
species of animals from all treatment diets goats made
significantly (P>0.01) more live weight gain on the average
than sheep (+0.012g vs - 0.05g/ kg W " ) per head per day
respectively.
CONCLUSION
The high moisture content of cocoa-pod and low soluble
carbohydrate content resulted in silages of high pH and high
moisture content.
Cocoa-pod kept for more than 24 hours becomes mouldy
under humid conditions and results in mouldy, unpalatable
silage when ensiled alone or in combination with grass.
These and the possibility of its commercial use as a
source for furfural production may be the major constraints for
its use as a source of animal feed in the future just as
molasses has been diverted to the production of alcoholic
drinks thereby making its cost prohibitive for inclusion in
animal feed rations.
ACKNOWLEDGEMENTS
The senior author wishes to express his profound gratitude to
the Senate Research Grant Committee of the University of Ibadan
for providing the funds for this study and also to acknowledge
430
the support given by the authorities and members of staff of
the Cocoa Research Institute of Nigeria (CRIN), Idi-Ayunre,
Ibadan, for providing the cocoa-pods and the facilities for
making the silages and in the determination of the pH of the
si I ages.
REFERENCES
Adegbola, A. A. and Omole, T.A. 1973. A simple technique for
preparing discarded cocoa bean meal for use in livestock
feed. Nig. Agric. J. 10: 72 - 81.
Adeyanju, S.A.; Oguntuga, D.B.A.; liori, J.O. and Adegbola,
A. A. 1975a. Cocoa husk in poultry diets. Mal. Agric.
Res. 4: 131-136.
Adeyanju, S.A.; Oguntuga, D.B.A.; Ilori, J.O. and Adegbola,
A. A. 1975b. Cocoa pod in maintenance rations for sheep
and goats in the tropics. Nut. Rep. Int. 11: 351 -
857.
Adeyanju, S.A.; Akinokun, 0. and Ariyibi, 0.0. 1976. Further
studies on the utilizations of cocoa pod in ruminant
rations. Nig. J. Anim. Prod. 3: 139-143.
Adeyanju, S.A.; Oguntuga, D.B.A.; Sonaiya, E.B. and Eshiett, N.
1977. Performance of chicks on diet containing graded
levels of cocoa pod. Nut. Rep. Int. 15: 165-170.
AOAC (Association of Official Analytical Chemists). 1970.
Official methods of analysis, 11th ed. AOAC, Washington,
D.C.
ARC (Agricultural Research Council). 1965. The nutrient
requirements of farm livestock. No. 2. Ruminants.
Printed by Her Majesty's Stationery Office, London, UK.
431
Awolumate, E.O. 1982. Chemical composition and potential uses
of processing wastes from some Nigerian cash crops.
Cocoa Research Institute of Nigeria. Annual Report.
Ibadan, Nigeria.
Bateman, J.V. and Fresnillo, B. 1967. Digestibility of
Theobroma cocoa when fed to calves. J. Agric. Sci. 68:
23-25.
Blaxter, K.L.; Wainman, F.W. and Wilson, R.S. 1961. The
regulation of food intake by sheep. Anim. Prod. 3:
51-61.
Burroughs, W.; Long, J.; Gerlaugh, P. and Bethke, R.M. 1950.
Cellulose digestion by rumen microorganisms as influenced
by cereal grains and protein rich feeds commonly fed
to cattle using artificial rumen. J. Anim. Sci. A 9:
523 - 530.
Crampton, E.W.; Donefer, E. and Lloyd, L.E. 1960. A nutritive
value index for forages. J. Anim. Sci. 19: 538-544.
Fraps, G.S. 1946. Digestibility and production coefficients of
poultry feeds. Texas Agric. Sta. Bull. 372.
Glover, J. and Dutchie, D.W. 1958. The apparent digestibility
of crude protein by non- ruminants and ruminants. J.
Agric. Sci. 51: 289-293.
Oguntuga, D.B.A. 1975. Some physical and chemical
characteristics of the pod husk of F, Amazon, Innitario
and Amelonado cocoa in Nigeria. Ghana J. Agric. Sci. 8:
115-120.
Olubajo, F.O.; Van Soest, P.J. and Oyenuga, V.A. 1974.
Composition and digestibility of four tropical grasses
grown in Nigeria. J. Anim. Sci. 38: 149-153.
432
Olubajo, F.O. 1981. The feeding value of two tropical grass
and grass pineapple pulp silages. World Rev. Anim.
Prod. VII: 37- 42.
Oyenuga, V.A. 1957. The composition and agricultural value of
some grass species in Nigeria. Emp. J. Exp. Agric.
25:237-255.
Steel, R.G.D. and Torrie, J.H. 1960. Principles and
procedures of statistics. McGraw-Hill Book Company, Inc.
London.
Van Soest, P.J. 1963. Use of detergents in the analysis of
fibrous feeds. II. A rapid method for the determination
of fibre and lignin. Assoc. Off. Anal. Chem. J. 46: 829-
835.
433
THE EVALUATION OF BREWERS DRIED GRAINS (BDG) IN POULTRY RATIONS
1. BREEDER CHICKEN RATIONS
R. Fombad and J. Mafeni
Institute of Animal Research
Mankon, Bamenda, Cameroon
ABSTRACT
In an attempt to establish the optimum level of brewers dried
grains (BDG) from a Cameroonian brewery that can be
incorporated in breeder rations without adverse effect on
productive performance, a study was carried out with 120 laying
hens and 12 cocks of Isa Commercial breed. A complete
randomised design was utilised in which the dietary treatments
contained 0, 10, 20, and 30% levels of BDG was fed. Feed and
water were provided ad I ibi tum over the 5-month experimental
period. Parameters such as egg production, egg weight, feed
intake, albumen height, egg shell weight, semen quantity,
fertility and hatchability of fertile eggs were measured.
Results showed that when BDG was fed at 30% level in the
ration, the hen-day production (50.6%) was significantly
(P<0.05) depressed than when the 0% level (56.2%), 10% level
(56.9%) and 20% level (56.7%) were fed. There was a
significant increase in egg weight with the increased level of
BDG in the ration. Also the feed intake per bird per day was
significantly (P<0.05) and progressively increased with
increasing levels of BDG. No significant difference was
noticed between treatments for ratio of shell weight to egg
weight, albumen height and semen quantity for birds fed the
0,10,20 and 30% levels of BDG. Although the amount of feed to
produce a dozen eggs increased significantly (P<0.05) as the
level of BDG increased in the diet, it was noticed that the
cost of feed required to produce a kilogram of eggs was
progressively reduced as the level of BDG increased in the
ration viz 455, 420, 406, 401 CFA (1US$ = 295CFA) for 0,10, 20
and 30% levels respectively. It would appear that the 30%
level of BDG can be tolerated but the 20% level of BDG was most
appropriate for breeder birds.
434
Constraints on the use of this by-product include
bulkiness of the wet grains, drying procedure and its high
fibre content.
INTRODUCTION
In Cameroon, one of the limitations to the expansion of the
poultry industry is the high cost of protein and energy
ingredients such as fish meal, decorticated cottonseed cake,
maize and guinea corn. In order to reduce this high cost,
efforts are being directed to the use of non-conventional feed
ingredients. Brewers dried grains (BDG) a by-product of the
beer industry might offer a suitable cheap substitute. Despite
the increasing number of brewers in Cameroon, knowledge about
the use of brewery by-products is almost non-existent. The
problem facing most of the breweries is that of disposing the
wet grains. Current disposal practices include free donations
of wet grains to any interested persons staying within the 25-
km radius from the brewery or payment of contractors by the
breweries to collect and dump the bulky daily output of the wet
grains. Currently the wet grains are used as manure, and a few
farmers in the Western province feed it to pigs.
BDG however contains a wide variety of essential
nutrients which are required in feed formulation for poultry.
Couch (1978) and Ewing (1965) analysed some BDG samples and
found that it contained over 20% crude protein, about 6% ether
extract, over 15% crude fibre and about 4% ash. Almquist
(1972) found that BDG contained 25% crude protein and that it
was fairly rich in essential amino acids i.e. 0.9% lysine, 0.4%
methionine, 0.4% tryptophane, 1.2% phenylalanine, 1.1%
threonine and 1.6% valine. It is therefore higher in protein
and amino acids than corn. Its use as animal feed does not
call for competition between man and livestock as in the case
of corn and other ingredients.
The use of BDG in poultry feed would not be without
constraints. The product is collected with moisture content of
about 80% which increases its bulkiness. It needs to be dried
435
before incorporation in poultry rations. Sun-drying is the
most common method used and this method requires large space
and large polythene sheets for drying. During drying the wet
grains have to be spread in a thin layer and frequently turned
to avoid fermentation which could result in lowering the
nutritive value of the by-product. The turning process is
tedious and time consuming. The present study was conducted to
evaluate the use of BDG in breeder poultry rations.
MATERIALS AND METHODS
A total of 120 laying hens and 12 cocks of Isa Commercial breed
were used in this trial. The layers which had been in lay for
120 days were randomly divided into four equal treatment groups
of 30 birds each and these were further divided into five
replicate groups of 6 birds each. The cocks were divided into
four dietary groups of 3 cocks each. The hens and cocks were
placed in cages in pairs and singly, respectively. The wet
grains were collected from Baffoussam, 90 km from Mankon
Station and sun-dried for 72 hours on black polythene paper and
stored in jute bags. Before the BDG and corn were used in the
formulation of the rations, a sample of each was analysed for
proximate composition and amino acid profile (Table 1a and 1b).
Table 1a. Proximate composition of brewers dried grains and
corn (dry-matter basis).
Ingredient | Brewers dried grains | Corn
Crude protein (%)
Crude fibre (%)
Ether extract (%)
Ash (%)
27.7
15.7
7.2
3.8
9.1
2.9
4.3
1.2
436
Valine X g
o _»
Tyrosine ' o
_»
Tryptophan s o
o o
C* o
Threonine w <o
o o
«K Phenylanine V/1 o
r\
o -*
%
rt
Methionine § o
■§ o o
o Lysine CO s
o!
o o
O
3
O Leucine 5 Wo
£ o r\j
Isoleucine V/l oV/l
o _»
Histidine CO oV/l
o o
Cystine 8
o
•
Arginine o
W
o -»
1 ^</> T-♦» a-♦l 10 3
c >< —.CO
rf ^■N a-i
v> -Io
I 3 «2-Jn o -1
-n o 00
zefr
A complete randomised design was utilised in which the four
dietary treatments (Table 2) containing 0, 10, 20 and 30%
levels of BDG were fed. In the formulation of the diets, the
other ingredients were adjusted to maintain iso protein,
energy, calcium and phosphorus levels as BDG was increased.
Palm oil was used to balance the energy levels.
The birds were transferred to their cages and left for a
week to adjust to the cage environment; within which period
they were fed a normal layer diet without BDG. Thereafter,
birds were fed for a week the experimental diet before data
collection started. Feed and water were provided ad I ibi tum
and record for feed consumption was kept. Eggs were collected
daily and records of daily egg production and egg weight for
all replicate groups were kept through the five months duration
of the trial. Average hen-day production was calculated. Two
eggs from each replicate group were taken daily at random,
weighed, broken and albumen height was measured as an
indication for egg quality (using a Haugh Unit gauge). The egg
shells from the broken eggs were washed and dried in an oven at
60 C overnight and weighed. The egg shell was expressed as a
percentage of the egg weight.
Semen were collected from the cocks by the massage
technique (Quin and Barrou, 1937). The semen quantity from
each cock was measured, then the semen from the same dietary
group was pooled and inseminated to the corresponding hens
offered the same diet. Approximately 0.1 ml of whole semen
(estimated to contain 8x10 spermatozoa, Yousif et al, 1984)
was inseminated into each hen. The artificial insemination was
done usually in the evenings, at about 4.00 p.m. when it was
assumed that the hens have laid and it was repeated at
intervals of 7 days.
438
Table 2. Composition of experimental rations.
Ingredient
Corn (yellow)
BDG
Cottonseed cake
Fish meal
Palm oil
Bone meal
Calcium carbonate
L- Lysine
Layer concentrate
Salt
Total (kg)
Analysis (dry-matter
basis)
Crude protein (%)
Crude fibre (%)
ME (kcal/kg), calculated
Calcium (%)
Phosphorus, total (%)
X level of BOG
0 10 20 30
63.5 57.5 49.5 42.3
0 10.0 20.0 30.0
17.5 13.0 9.0 4.7
5.6 5.6 5.6 5.6
2.1 3.1 5.1 6.7
3.0 3.0 3.0 3.0
7.1 6.6 6.6 6.5
0.2 0.2 0.2 0.2
0.5 0.5 0.5 0.5
0.5 0.5 0.5 0.5
100 100 100 100
17.8 17.7 17.7 17.8
3.5 4.4 5.3 6.2
2949.9 2931.3 2931.3 2929.5
4.4 4.5 4.5 4.4
0.78 0.77 0.77 0.75
SADE (Cameroon) layer concentrate supplied per kg the following:
Vitamin A 9000 IU; vitamin D, 1800 IU; vitamin E 14.4 mg;
Vitamin K 1.4 mg; vitamin B. 1.0 mg; vitamin B~ 4.1 mg;
Vitamin PP 18 mg; calcium patothenate 9 mg; vitamin B, 1.8 mg;
Vitamin B.- 0.02 mg; folic acid 0.7 mg; biotin 0.06 mg; choline
chloride 300 mg; BHT antioxidant 120 mg.
439
The eggs from each dietary group were marked after
collection, identification and stored in a cool room (18°C) for
two weeks before incubation. On the seventh day of incubation
the fertile eggs were detected by candling the eggs using a
locally made candler. The hatchability was calculated by the
number of fertile eggs.
The different rations were analysed for their proximate
analysis using methods outlined by A.O.A.C. (1975). Data
collected were subjected to statistical analysis (Steel and
Torrie, 1980) and significant means were tested according to
Duncan's Multiple Range Test (Duncan, 1958).
RESULTS AND DISCUSSION
The results on the laying performance (Table 3) show that
feeding up to 20% of BDG did not significantly affect the hen-
day production. However, the laying performance was
significantly (P<0.05) depressed when the ration containing 30%
BDG was fed. The average hen-day production percentages for
the 0, 10, 20, and 30% levels of BDG were 56.20, 56.88, 56.65,
and 50.59, respectively. These results are contrary to the
findings of Onwudike (1981) who reported that the laying
performance was not significantly affected when BDG was fed up
to 40%. Although the amino acid levels of diets were
increasing as the BDG levels in the rations increased, the fall
in egg production at 30% levels of BDG in the ration may be
caused by high crude fibre level of the ration at this level.
440
Table 3. Calculated amino acid composition of experimental
diets.
Amino acid
Level of BDG (%) in the rations |
0 10 20 30 |
| Arginine 1.25 1.12 1.09 1.04 |
| Cystine 0.26 0.48 0.49 0.48 |
| Histidine 0.45 0.40 0.38 0.37 |
| I so leucine 0.79 0.85 0.90 0.94 |
| Leucine 1.75 1.90 2.03 2.14 |
| Lysine 0.96 0.95 0.96 0.96 |
| Methionine 0.27 0.28 0.33 0.38 |
| Phenylalanine 0.87 0.85 0.82 0.80 |
| Threonine 0.65 0.65 0.65 0.66 |
| Tryptophan 0.21 0.21 0.22 0.23 |
| Tryrosine 0.09 0.21 0.33 0.45 |
| Valine 0.79 0.84 0.88 0.93 |
The egg weight progressively increased with the level of
the BDG in the rations. Birds fed the ration containing 10%
level of BDG laid significantly (P<0.05) larger eggs than those
on the control ration (62.30 versus 60.76 g respectively).
Also feeding 30% level of BDG significantly (P<0.05) increased
the egg weight (63.95 g) as compared to (62.30 g) in the ration
containing 10% level of BDG. There was, however, no
significant difference in egg weight for birds fed the 20 and
30% levels of BDG. The improved egg size may be due to the
increase of amino acid pattern (Table 4) caused by increased
441
BDG levels in the rations which may increase the egg protein
synthesis and hence larger egg sizes. This could be in part as
a result of higher linoleic acid level which correspond to
higher BDG levels. Bragg quoted by North (1972) stated that
increasing the linoleic acid in chicken diets could raise the
deposition of polyunsaturated fatty acids in the egg yolk from
a basic level of about 5% to approximately 28%. The average
feed intake per bird per day significantly (P<0.05) increased
with increasing levels of BDG. The average feed intake for the
0, 10, 20 and 30% levels of BDG were 100.71, 111.69, 122.97 and
130.51 g respectively. This same trend was noticed by Owudike
(1981). The trend in feed intake could not be related to the
energy levels of the rations since the rations were about iso
caloric. One of the possible reasons for this difference in
intake could be the greater tendency for the birds to spill the
feed in search of grains when higher levels of BDG were fed.
There were no significant differences noticed between
treatments for the ratio of shell weight to egg weight, albumen
height and semen quantity for birds fed the 0, 10, 20 and 30%
levels of BDG. The egg shell did not then contribute to the
difference in egg weight. The various levels of BDG did not
also affect the quantity of semen produced by the cocks.
Although the fertility percentage increased with increased
levels of BDG in the rations (Table 4) this increase was not
significantly different between dietary treatments. The
percentage hatch of fertile eggs increased by the increase in
the level of BDG in the diets. The hatchability for fertile
eggs from birds fed BDG was significantly (P<0.05) greater than
those of the control group (Table 4).
442
o&
§
c
a
i_
0)
i
01
at
+ i? g s V1
z * * *.. o 8 ro C «Uj n n s in ro o
CO ro ^* >o (\l ■■ •~ CM ro
+ 1 «- o «-
a a a
o o
a* in «- o r- ro >* IM
18
o
m o* m ■* CO o ro
*-*
ro o ro o
m 1o ro
<>
|
CO «-
m oo
X
V^
-O -
(3 ro ro .0
m «- K 8 o in «- roO p ^) in o ro o oo asCD
(M
o oj cM o cM
o
"~1 s so In >o CM
(A
01
>
01 ro -Q u
r~-
n
—1
O
eg o o
33 ro <0 CO
in
o ro oo
■o <u «- o- »— «— O in
in r>-in 1o «— o
■ —
3
u
Cs1 >0 «— o- «- o
o . S. s in ^J■ m CM
•o o o i> .-! .J od r^
in nO o O m <o*12 "
^^
»*\^
*->
^
/-> '5 ^s.^> O) 3 *->
*e >^
s J?>
01
„
s ■8 *-' e v-/^ 4J -C *-* «
(A *-' T3 £ <7> O)
4j i l_ o> D J* s?^\ ■O ro (Ja O)
0>
£ ■C O 01
i—
D.
1^
4-' -* *-' >*
>* £ Q u -§, *-»
-8 c .C *-* w flja> U) iu c
X
<4-
) 3 -C gC 1 •*- *-' H-a> O) O a- •- o.c O)
1 i01 H- O> > > ro a> ro< < «£ OL < CO U_ Z
O) «-*
8
ro
01
i_
at *->
l.
ro u>
*-»
a i s B
i_ !/> H i°
u 01 01 ro« o L. 1
|
l_
0)
(A
a> • •- O
*•- T3 l/>
i
4J (_
1D cro O*-» u
a>
V Is H- T7o ( l_
SZ F |
3
o>
a
ro
in V) (A
V)
o
II II ii
r o
Xro V
0) a. 1fl Uj
443
However, the hatchability for the 20 and 30% levels of BDG in
the rations was significantly (P<0.05) greater than those of
10% levels of BDG (80.93, 81.32 versus 75.84%, respectively).
Kienholtz and Jones (1967) attributed this improved fertility
and hatchability of fertile eggs to an unidentified factor in
BDG.
A view of the economic analysis of feeding (Table 5)
shows that feeding above 20% level of BDG significantly
(P<0.05) increased the amount of feed required to produce a
dozen eggs. It was also noticed that the cost of feed required
to produce a kilogram of eggs was progressively reduced for 0,
10, 20 and 30% levels of BDG in the rations. The cost was 455,
420, 407, 401 CFA respectively. This reduction in price with
increase in the level of BDG was a result of the fact that BDG
cost was less than corn, 40 vs 100 FCFA a kg, respectively.
Table 5. Economic analysis of feeding BDG to breeder birds.
Economic analysis
Cost/100 kg of ration (CFA)1
Cost of feed/dozen eggs (CFA)|
Cost of feed/kg eggs (CFA)
Kg feed/dozen eggs (kg)
Levels of BDG (%)
1 ° 10 20 30 +SEM
| 15,698 15,013 14,529 13,982
I 315 328 393 479
| 455 420 406 401
| 2.01b 2.19b 3.04a 3.43a
0.065
Means with the same superscript are not significantly
different at (P<0.05).
1
295 CFA is equivalent to 1 US dollar.
2
Only the kg feed/dozen eggs was analysed statistically.
444
CONCLUSION
The results showed that 30% level of BDG can be tolerated in
layer diets but 20% level of BDG in the rations would be the
most appropriate level for breeder birds. With the high
fermentation properties of the wet grains drying should be done
only in the dry season and it is hoped that drying houses would
be designed to dry the wet grains in the rainy season. This is
to assure an all year round dried grains that would not stand
the risk of contamination as a result of long storages.
The major limitation to the use of this by-product in
poultry rations was its high fibre content. The high fibre
content resulted in lower digestibility of the rations
containing high amounts of BDG.
ACKNOWLEDGEMENTS
The authors acknowledge with thanks the Ministry of Higher
Education and Scientific Research (MESRES) for the funds that
supported this study and Dr. R T Fomunyam for her useful
suggestions. The technical assistance of Mrs. E. Forchap and
L. Ngassa is also appreciated.
REFERENCES
Almquist, H.J. 1972. Protein and amino acids in animal
nutrition. S.B. Penick and Co., New York.
AOAC (Association of Official Analytical Chemists). 1975.
Official methods of analysis. 12th ed. AOAC,
Washington, D.C.
445
Couch, J.R. 1978. Brewers dried grains in poultry feed.
Poultry International, July, 42.
Duncan, D.B. 1958. Multiple Range and Multiple F. tests.
Biometrics 1: 1-42.
Ewing, W.R. 1965. Poultry nutrition. 5th ed, Pasadena, Ray
Ewing Co., Pasadena, California. pp. 396-418.
Kienholtz, E. W. and Jone, M.L. 1967. The effect of brewers
dried grains in some poultry rations. Poultry Sci. 46:
1280.
North, M.O. 1972. Commercial chicken production manual. The
Avi Publishing Co. Inc., west Port, Connecticut. 454 pp.
Onwudike, O.C. 1981. The use of brewers dried grains by laying
hens. Nutr. Rep. Int. 24 (5): 1009.
Quin, J. P. and Barrows, W.H. 1937. Collection of spermatozoa
from domestic fowl and turkey. Poultry Sci. 16: 19 -
24.
Steel, R.G.D. and Torrie, J.H. 1980. Principles and procedures
of statistics. McGraw-Hill Book Company, N.Y.
Yousif, Y.F; Ansaband, G.A. and Buckland, R.B. 1984. Effect of
selection for fertility of fresh and stored semen.
Poultry Sci. 63: 1475-1480.
446
EFFECTS OF INCORPORATING RUBBER SEED MEAL SUPPLEMENTED
WITH BLOOD MEAL IN BROILER RATIONS UNDER TRADITIONAL CONDITIONS
Nouke and H.N. Endeley
C.R.Z. Wakwa, B.P. 65, Ngaoundere-Cameroon
Ministere de I 'Enseignement Superieur et de la
Recherche Scientifique (M.E.S.R.E.S. )
Direction GeneraIe, Yaounde, Cameroon
ABSTRACT
A trial was carried out to investigate the effects of the
incorporation of rubber seed meal supplemented with blood meal
as sources of plant and animal protein on the performance, feed
intake and the carcass of poultry birds from day-old chicks to
12 weeks under traditional system of management.
Unsexed 300 Jupiter chickens were randomly divided into
4 groups each of 75 birds. Four diets representing different
levels of rubber seed meal (RSM) and blood meal (BM):- R0 with
0% RSM and 0% BM; R10 with 10% RSM and 8% BM; R20 with 20% RSM
and 6% BM and R30 with 30% RSM and 4% BM were fed ad libitum
throughout the experimental period. Results showed significant
differences between treatments indicating the superiority of
the diet supplemented with 30% RSM and 4% BM.
INTRODUCTION
During the past years the world's population has greatly
suffered from food problems, and more particularly from protein
deficiency in the diet. According to the Food and Agriculture
Organization (F.A.O., 1982) a third of humanity suffers from
quantitative malnutrition. This is crucial in Africa where the
daily ration of 11 grammes of protein is far from the
physiological minimum of 30 grammes as recommended by the
F.A.O. In order to solve this problem of animal protein
deficiency, developing countries have to improve on their
animal husbandry. This could be done by good managerial
447
techniques, and by improving the plane of nutrition.
Alternative sources of feed ingredients should be found which
are not utilised by the human population and which, at present,
might not have found wider use in animal feeding.
The objective of this study was to investigate the
effects of the incorporation of rubber seed meal supplemented
with blood meal as source of protein in broiler rations in
replacement of cottonseed cake and groundnut cake under
stimulated traditional management conditions on chicken growth,
feed consumption, efficiency of feed utilisation, mortality
rates and the characteristics of the carcass often slaughtered.
MATERIALS AND METHODS
These studies were conducted in the teaching research farm of
the National Advanced School of Agriculture (N.A.S.A) at
Nkolbisson (Yaounde, Cameroon).
Animal material and lodging
Unsexed 300 Jupiter day-old chicks weighing an average of
36.24+4.01 g were used in this study.
These chicks were randomly divided into 4 groups each of
75 chicks corresponding to 3 levels of experimental rations and
a control group. The groups were shared into identical lodges
measuring 4x2 meters made of wood, the roof covered with zinc
and a concrete floor covered with wood sharings. Around each
lodge was a pasture surrounded with wire meeting. Heating
during the starter period was done using two paraffin lamps per
lodge.
EXPERIMENTAL RATIONS
Preparation of blood meal
The used blood was collected from the Central Abattoir in
Yaounde immediately after cattle were slaughtered. After
collection, the blood was boiled immediately in a cask for 45
448
or 60 minutes in order to let water evaporate and destroy any
parasites. After boiling it was then dried in an oven at 68-
83°C for 5 to 6 days, and then ground into flour.
Preparation of rubber seed meal
The rubber seeds were bought from the local market. After
manual decortication, the kernels were boiled for 45 min. to
reduce the potential toxicity. They were then dried at 55°C
for 72 hours and later ground into brown flour.
Diet formulation and chemical composition of these diets
are presented in Table 1 and 2, respectively.
Table 1. Composition (%) of the experimental diets.
Diet ingredients R0 R10 R20 R30
Maize 60 50 36 24
Wheat bran 8 20 26 30
Concentrate 10 10 10 10
Cottonseed cake 10 - - -
Groundnut cake 10 - - -
Rubber seed meal - 10 20 30
Blood meal - 8 6 4
Phosphate dialcaline 1.5 1.5 1.5 1.5
Salt 0.5 0.5 0.5 0.5
Total 100 100 100 100
449
Table 2. Chemical composition of the experimental
rations (calculated).
Composition (%) Rations
R0 R10 R20 R30
Dry matter 88.36 87.05 88.30 88.66
Crude protein 20.70 21.20 21.00 20.00
Crude fiber 3.70 2.34 2.47 2.58
E.M.A. 4.72 7.20 10.74 14.32
Ash 5.37 5.05 5.28 5.47
Ca 1.25 1.28 1.28 1.21
P 0.86 0.84 0.89 0.98
Energy (cal) 2846 2986 3030 3115
N.B. R0 ration with 0% of rubber seed cake and 0% of blood
meal .
R10 Ration with 10X of rubber seed meal (RSM) and 8% of blood
meal (BM).
R20 Ration with 20% of RSM and 6% of BM.
R30 Ration with 30% of RSM and 4% of BM.
Management
Each experimental group was offered its corresponding diet ad
I ibi tum and they had free access to water. Hygienic conditions
were followed to keep the drinkers and feeders always clean.
Feeds offered were weighed. At the end of the week the
residues were weighed and deduced from the introduced amounts.
The chickens were weighed weekly before being given food. All
mortality cases were registered.
Carcass analysis
After the three-month experimental period, five chickens were
taken from each group for carcass analysis. The following
measurements were taken into account:
450
- Weight of blood
Weight of edible carcass
Chemical composition.
Data collected were statistically analysed using the randomised
complete design, while significantly different means were
identified using the Duncan Multiple Range test (Steel and
Torrie, 1960).
RESULTS AND DISCUSSION
Chicken growth
a. Starter period
Table 3 presents the weekly weights of birds on each of the
experimental diets. The highest growth was achieved on the
control diet followed by diets R30, then R20 and R10.
Statistical analysis revealed significant treatment effects on
the growth performance of the birds (P<0.05).
It was observed that at the end of the experiment (12
week), the trend of growth noticed during the starter period
persisted during this period with groups R0 and R30 having
higher average weekly body weights. Statistical analysis
revealed significant differences between the average weekly
weights in each treatment (P<0.05) as shown in Table 3.
Results obtained in this study showed that average
weekly body weight increased with increasing levels of RSM
during the starter and grower periods. Statistical analysis
indicated significant differences between treatments.
Buvanendran and Siriwardence (1970) reported that as
incorporation levels of RSM went up to 30%; growth decreased.
Rajaguru et al (1971); Tchounken (1982) and Nzumo (1983) also
reported that growth decreased as RSM incorporation levels
increased in poultry rations.
451
Table3.Averagewe klyeights(g/ ird)overthexp rimen alp o .
Weeks11345679101 diets
R0X46.1014 4130 121 1 616 6959 0903 53.31 09 5061 1 114
a
DO5.0911.14 169 8111 36 ."6 419 1418 52403 2 64 1
R10X43.5461 190 6013006 12112.123" 0155M 59 5 91 8."49 .01
b
■e.DD5.61211. 12 644 06"1.10114 900 1966 401 9 7335 1 *>R10X51.191 411 .60114 53 03 8 35 9 6569 .111 0 2051 06
cb
DO5.3411.105 4376 5134 919 2.09 "300 9469.134 09 94 R30X124."53.0311 61916940 1663 37 1 1910 6 0151 59 2 0
dc
DD4.1111 912.055 66 691317 1261D.0 200 0033 3456
N.BX=averageweeklyeight.
DD■standarddeviation.
Incolumns6and11scriptswiththesamelettersan
significantlyd fferentatP<0.05levels.
Average weekly body weight gain
Table 4 showed that during the first 6 weeks the higher average
weight gains were noticed in treatment R0 (control) followed by
groups R30 and R20. No statistical differences (P<0.05) among
treatments were observed, but the lowest average weight gain
was recorded in treatment R 1 0 . During the second 6 weeks R0
continued as the superior treatment followed by R20 then R30.
Statistical analysis showed that higher weight gains were
obtained in treatment R0 and the lowest in R10 but -these
differences were not significant. (Table 4). The total weight
gain over the whole period showed significant differences
between treatments R0; R20 and R30 (P<0.05). The individual
weekly weight gains showed no significant differences between
the four treatments except in group R10. These results agree
with those of capital et al (1971).
Table 4. Average weekly body weight gain (g/poulet/week) .
Starter F i n i t i on Ent i re
period period period
Diets 1st-6th week 7th-12th week 1st-12th week
R0 103.71+65.64
— a
270.75+243.13
— a
194.92+99.45
— a
R10
33. 87+21. 45b 180. 45+47. 55b 121. 82+81. 84b
R20 66.33+39.48
— a
224.53+47.13
— a 152. 62+12. 84b
R30 68.56+37.71
— a 222. 49+47. 72a~ a 152.52+88. 10fa
N.B. In column, numbers script with the same letter are not
significantly different at P<0.05 level.
453
Feed consumption
Feed consumption increased when rate of blood meal decreased in
the diets (Table 5). During the first period (1st-6th week)
the group without seed meal recorded higher feed consumption.
Statistical analysis revealed a difference between treatments
R10 and R20 on the one hand and R30 and R20 on the other. In
the 2nd six weeks the same trend of the 1st period continued
but without significance.
Table 5. Average weekly feed consumed (kg).
Starter Fi nit ion Entire
period period period
Diets 1st-12th week 7th-12th week 1st-12th week
R0 289. 94+16. 47fl 980.51+14. 17fl 622. 98+34. 01a
R10 130. 70+86. 43b 620. 94+20. 33b 398.1 0+29. 20fe
R20 189. 00+8 1.88bc 616. 67+14. 22fa 421 .82+24. 42fac
R30 209.98+16.68^ 716. 19+10. 65 ,. 486.09+27.54,.
— c - c — c
N.B. In column, numbers script with the same letter are not
significantly different at P<0.05 level.
Over the whole experimental period, it was confirmed
that the blood meal combined with rubber seed meal had a
depressing effect on feed consumption; a finding that agrees
with Spring and Day (1981).
454
Efficiency of feed utilisation
Table 6 summarises the average weekly feed utilisation
efficiency during the trial period. The best feed conversion
was noticed in R0 and the lower in R20 with no significant
differences between treatments. The present results confirmed
those of Rajaguru et al (1971), and Tchounken and Tchouboue
(1982). The starter period got the highest mortality (1%, 1,
6%, 0% and 0%) respectively for R0, R10, R20 and R30.
Table 6. Average weekly feed utilisation efficiency.
Starter Fi nit ion Entire
period period period
Diets 1st-6th week 7th-12th week 1st-12th week
R0 2.90+0.66a 3.42+0.86fl 3.19+0.82a
R10 3.87+1.50a 3.41+0.70fl 3.59+0.90g
R20 3.32+0.92g 3.47+0.85g 3.40+0.90a
R30 3.05+0. 17. 3.39+0.92 3.23+0.71
— a - a - a
N.B. In column, numbers script with the same letter are
significantly different at P<0.05 level.
Carcass analysis
a. Edible carcass
The highest average edible carcass weight was recorded on R0
while the lowest was on Diet R10 as shown in Table 7.
Statistical analysis revealed significant differences between
455
treatments from R20 on the one hand and R30 on the other
<P<0.05). Birds from the control group had significantly
higher weight than those of the treatments. These results
agree well with those of Tadle et al (1955).
Table 7. Edible carcass (kg).
Replications
Diets
A B C D E Mean (g)
RO 2462.,70 2377..90 2178.00 2188.50 1996 .20 2240.•66a
R10 1583..20 1602..30 1999.30 1762.60 1611,.30 1631.'74b
R20 2128..70 1964..40 2317.80 1733.10 1991,.80 2025.•17a
R30 2169..60 1653..10 2054.50 1617.80 1617,.80 1819. 02b
N.B. In column, numbers script with the same letter are not
significantly different at P<0.05 level
b. Chemical composition
Chemical analysis of carcass showed that R30 gave the best
result in terms of protein content. Fat content varied from
25.36% for R30 to 34.40% for R10 group. It would appear from
the results that as rubber seed meal increased in the diets,
the protein content of the carcass increased.
CONCLUSION AND RECOMMENDATIONS
From the results obtained in this investigation on the effects
of incorporation of rubber seed meal (RSM) supplemented with
blood meal (BM) as sources of protein in broiler rations under
456
traditional management conditions, it appeared that the diet of
30% RSM supplemented with 4% BM gave the best results without
any adverse effects on performance. It might be suggested from
the present investigation that in future studies, it would be
necessary to deal with the level of RSM supplemented with BM at
levels less than 5%. This may provide more information on the
effects of incorporation of these by-products in poultry
rations.
REFERENCES
Anon. 1964. The utilisation of pararubber seed. Bull. Imp.
Inst. 2.551.
Bessilieve, J. 1975. L'elevage du poulet, Flam.
Bredenann, G. 1931. Does the H.C.N, content of rubber
seed adversely affect the use of rubber seed cake as
animal feed. Der tropen I Flamzer.
Buvanendran, B. and Si riwardence, J. 1970. Rubber seed meal
in poultry diets. Ceylon Vet. J. 18.
Delage, J. 1974. Adapte par Brankaest R. Memento sur
I 'al imentat ion des animaux domestiques. Edite par
Offset par la division de pedagogie rurale, E.N.S.A.,
Yaounde.
El let, W.B. 1930. Feeding hevea rubber seed meal for milk
production, Virginia, Agric, exp. Station Bull. 41.
F.A.O. (Food and Agriculture Organization). 1982. Population
and food supply. FAO, Rome.
F.A.O. 1981. Revue mondiale de zootechnie. Vol. 40, Horizon
2000. FAO, Rome.
George, C.D.V.; Green Sheet, V.R. and Teik, G. 1932. Storage
of rubber seeds. Malaysian Agric. J. 20: 164 - 176.
457
Gohl, BO. 1961. Tropical feeds. F.A.O. Animal Production and
Health series 12. FAO, Rome.
Kouba, C. 1981. Disponibi I i tes en sous-produits des agro-
industries et abattoirs et leur possibilities
d'uti I isation au Cameroun, Memoire de fin d'etude.
E.N.S.A., Yaounde.
Malfiroy, F. 1960. Modernisation des abattoirs. Importance de
I 'organisation rationnelle de la recuperation de tous les
sous-produits d'abattoirs. Vigot freres.
National Academy Science Research Council of U.S.A. 1966.
Nutrient requirement of poultry. 5th revised ed. Publ.
No. 1345.
Nzoum, E. 1983. Effet de substitution du tourteau de coton
par le tourteau d'hevea dans la ration demarrage et
finition du poulet de chair. Memoire de fin d'etudes.
E.N.S.A., Yaounde.
Oluyemi, J. A. and Roberts, F.A. 1979. Poultry production in
warm wet climates. Muthilan, Intem College Ed.
Rajaguru, A.S.B. 1973. Effects of rubber seed meal on the
mature chickens. J. National Agric. Sc. of Ceylon. Vol.
8, No. 2. Rubber Research Institute of Sri Lanka.
Siriwardence, J. and Nugana, D. 1972. Metabol isable energy of
rubber meal in poultry diets. Ceylon Vet. J. 20 (3): 61-
63.
Spring, F.G. and Day, F.W.F. 1981. The oil contents, keeping
qualities and commercial possibilities of para rubber
seed. Agric. Bull. F.M.S. 6 (5): 251-244.
Steel, R. and Torrie, J.H. 1960. Principles and procedures of
statistics. McGraw-Hill Book Co., N.Y.
458
Stosic, D. and Kakay, M. 1981. Graines d'herea dans
l'alimentation des animaux domestiques. Revue
Mondiale 200, 39: 29-39.
Tchunken, D.M. 1982. Essai de substitution du tourteau de
coton par le tourteau d'hevea dans l'alimentation des
poulets de chair. Mémoire de fin d'études, E.N.S.A,
Yaounde.
459
THE EFFECT OF WATER LETTUCE (PISTIA STRATIOTES L) AS A
SUBSTITUTE FOR WHEAT MIDDLINGS IN BROILER FINISHING RATIONS
Y. Man jeli; J. Tchoumboue and J. Djoukam
Department of Zootechnie
Centre Universitai re de Dschang
Cameroun
ABSTRACT
One hundred 6-week-old broiler chickens with average weight
ranging from 892 to 921 g were randomly distributed into 5
groups of 20 each in a completely randomised design. Each group
was fed one of the following experimental rations containing 0,
5, 10, 16 and 20 % water lettuce (Pistia stratiotes L) as a
substitute for wheat middlings for 4 weeks.
The best performance in terms of feed efficiency (2.74)
was obtained with birds fed, the ration containing 10% water
lettuce. The average daily weight gain was 44.56 g/day and cost
per kg live weight gain was 284 CFA (US$ = 295 CFA in 1987).
This preliminary study indicated that 10% water lettuce
may be recommended in finishing rations of broiler chickens.
460
THE USE OF ORGANIC MANURE IN AQUACULTURE. I. POLYCULTURE OF
TILAPIA (OREOCHROMIS NILOTICUS) AND AFRICAN CATFISH (CLARIAS
LAZERA) IN EARTHEN PONDS RECEIVING CHICKEN MANURE WITHOUT
SUPPLEMENTAL FEEDING
D. Nguenga
Institute of Animal Research (IRZ)
Foumban Piscicul tural Research Station
P.O. Box 255, Foumban, Cameroon
ABSTRACT
An experiment was conducted at the Foumban Piscicultural
Research Station in order to evaluate the efficiency of chicken
manure on fish yields. The polyculture was composed of Tilapia
(Oreochromis ni loticus) and African catfish (Clan as lazera) .
Three 400-m ponds were used and loaded with 1.75 fish/m .
Chicken manure was applied at a rate of 40 kg dry matter per
hectare pond per day at the start of the experiment. Waste
allowance was adjusted biweekly with an addition of 20 kg dry
matter/ha. Ponds were manured 6 days a week. Cow manure (150 kg
dry matter/ha) and mineral fertiliser, NPK 20, 10 and 10 (100
kg/ha) were applied alternatively at 2-week intervals in order
to strengthen the effect of chicken manure. Throughout the
experimental period no other supplemental feeds were added to
the ponds. Additional water was only added to replace losses
due to seepage. The mean survival rate was about 66%. Fish
kills were probably due to predation by birds during the dry
season. The total fish biomass was 3.4 tonnes per hectare per
year. This zootechnical value reveals that Tilapia and Clarias
can thrive on natural foods (the manures and NPK used) in ponds
(zooplankton and phytoplankton) without other supplemental
feeding.
461
GOAT KEEPING
Mrs. E. Tendo
BP. Mbengwi, Momo Division
Bamenda, Cameroon
I thank you for the opportunity given to me to speak to you
about my goat farm. My husband and I are parents of eleven
children. And so in 1946 I started rearing goats in order to
help our large family have enough meat, especially during the
Christmas and New Year celebrations. The second reason was so
that I could get manure to apply to my yam and maize in my
gardens. It helps greatly with more food and I use the same
piece of land every year. I do not need to buy fertilizer. I
started with 6 goats: 5 nannies and 1 buck. Now I have 24
adult females: 6 young females and 10 young males, in all a
total of 40 goats. I do not keep milk goats because I have no
labour.
When I started goat rearing my children and I used to
tether or tie them singly in various places where we found good
grass. In the evening, we would loosen and let them into an
old abandoned house for the night. But we could not increase
the number because of frequent transfers of my husband who was
a civi I servant.
When my husband retired in 1984, we acquired a large
piece of land of our own. I then started to increase the
number of our goats. We built a small fence and a goat shed for
them. But we still tethered them wherever grazing was
available and only brought them into the small fence and shed
in the evening. This is now getting to be a big problem as I
have to do the job alone when the children return to school.
In the rainy season there is enough grass around our
compound for the goats but in the dry season there is not
enough grass and they grow thin. In the dry season we let them
drink once a day. We do this by taking water in a pan or basin
to where we have tied them. We sometimes give them salt.
462
Recently, I heard from the research people that it was
good to feed our goats with cassava peelings or waste, maize
stalks, groundnut or haulms which we used to throw away or bury
in the farm as manure. This advice has really helped our goats
to grow well especially in the dry season when there is very
little grass for the goats. Also in this way, I can keep the
goats in the little fence and feed them with these farm wastes.
It also reduces the burden of tying them and solves the problem
of destroying food crops when they break open from the tethers.
I just allow them to breed on their own. That is, the
buck lives with the nannies and mates them any time. I do not
control the mating or breeding. And when I find a good male I
buy it and sell the old one. The adult female produces a kid
every year.
Usually when any of the goats has scabies or some other
diseases I take them to the Veterinary Clinic for treatment.
Sometimes I treat them myself, especially if it is diarrhoea,
by using medicine for humans for this disease.
I usually take my goats to the local market and sell
them when I need money. When my children come on holidays, I
kill one to celebrate their good results. We eat some during
Christmas and New Year celebrations. When I visit my children
who are now married and working in Yaounde, I take a goat as a
gift to them.
The big problem I face in goat farming is the lack of
money to build a good large fence and a shed to keep the goats
in permanently, for I really want to increase the flock up to
over a hundred. It is very difficult for me to apply for a
loan. I need technical advice on how to apply for a loan. I
also need technical advice on how to build fences and a goat
shed. The other problem is that there is no good grass in the
dry season for the goats. I just let them eat whatever they
can find. I am very happy about my goat farm because it helps
us increase our family income, pay school fees, buy clothes,
eat fairly adequately and solve other family problems.
463
I take this opportunity to thank the organisers of this
workshop for giving me the chance to be here and the Ministry
of Women's Affairs in Mbengwi, Momo, who have given me the
encouragement to come to this meeting. Goat rearing is a
traditional thing for men but now with their encouragement and
advice many women will find it easy to keep goats. Thank you.
464
RECOMMENDATIONS OF THE FOURTH ANNUAL ARNAB WORKSHOP
1. The role of small ruminants as important utilizers of by
products should be recognised. Account should also be
taken of their selective nature.
2. Caution should be exercised in extrapolating data from one
species to the next, e.g. goats vs cattle, sheep vs cattle.
It is recommended that more production studies involving
the comparison of different species of equivalent
physiological maturity be undertaken.
3. Development of simple machinery such as choppers or chaff-
cutters would be beneficial in reducing by-product particle
size and assist in the harvesting process. Collaboration
with agricultural engineers on the design and use of
appropriate machinery is called for.
4. Transport is recognised as a major constraint, both on-farm
and on a regional basis where by-products may be located in
a different area to livestock. This question will need to
be addressed and where applicable integration of crop and
livestock systems is recommended using a systems approach.
It is also recommended that more thought be given to the
transference of technology to farmers and extension
personnel.
5. The limitations of conventional statistical methods in the
design, execution and interpretation of on-farm livestock
experiments needs to be addressed in order to come up with
appropriate solutions.
6. ARNAB members are urged to consult expert statisticians or
biometricians for help in the design and analysis of
experiments. Where expert advice is not available in
national agricultural systems (NARS) researchers may like
to send their research protocols/proposals to ILCA, through
the ARNAB Co-ordinator for advice and possibly subsequent
analysis of data.
465
7. The importance of standardising feed description through
the use of the International Network of Feed Information
Centres (INFIC) system would be desirable so that ARNAB
members speak the same "language". This would help to
unravel the causes of a lot of conflicting results on
apparently similar materials. It is suggested that
ILCA/ARNAB act as the coordinator for this excercise.
8. The need to collaborate with agronomists to get information
on grain: stover ratios in order to obtain accurate
inventories of by-products is stressed and to get
information on the roles and effectiveness of multipurpose
food crops. Available data from FAO and from NARS should
be used.
9. Research on harvesting and storage of crop residues should
be encouraged and researchers pay attention to the
economic, labour and other logistical problems which are
likely to arise.
10. Processing of crop residues can improve utilization and
there is a need to consider appropriate methodologies and
technologies for different situations and locations. Some
of the processing methods considered should include
ensiling, drying, alkali treatment if economical, and
hydration.
11. Antiquality factors which may limit the utilization of
otherwise nutritive by-products need to be specified and
quantified to enable appropriate solutions to be found.
12. Supplementation of by-product with appropriate materials
has long been accepted as a way of improving utilization of
these residues. The materials which may be used include:
a) legume crop residues
b) browse legumes, e.g. gliricidia. sesbania and leucaena
c) forage legumes, e.g. lab lab and others that may be
appropriate in the mixed farming system
d) NPN and protein nitrogen
466
e) energy e.g. molasses, bran and other agricultural
industrial by-products such as oil cakes
f) mineral supplements.
13. There is a need to study the possible ant i -nutritional
factors of some materials cited above; i.e. supplementation
of by-product with appropriate materials.
14. The use of by-products in non- ruminant feeding systems
should be encouraged, but consideration should be given to
toxic substances which may be passed, through animal
products, to human beings.
15. Alternative and competitive uses of by-products should be
borne in mind so as to diversify research to other products
which show more potential as livestock feeds.
16. Finally, there is a dire need to follow up recommendations
of workshops through early implementation. It is
recommended that ARNAB secretariat expedite the circulation
of recommendations perhaps within two months of the
Workshop, instead of waiting until the publication of the
proceedings. It is also noted that in spite of reminders
to the authors only a few papers were trimmed to the theme
of the Workshop which was spelt out as "Overcoming
constraints to the efficient utilization of agricultural
by-products as animal feed". It is recommended that in
future it is important to stick to the theme of the
workshop to save time on editing.
467
LIST OF PARTICIPANTS
BOTSWANA
Berhane Kiflewahid
Animal Production Research unit
P. Bag 0033, Gaborone
BURKINA FASO
Kassu Yilala
Semi -Arid Food Grain Research and Development
Co-ordination Office, OAU/STRC
B.P. 1783, Ouagadougou
CAMEROON
T. Beramgoto
Institute of Animal Research
Bambui Experimental Station
P.O.Box 80, Bamenda
R. Fombad
Institute of Animal Research
Mankon, Bamenda
R . T . Fomunyam
Institute of Animal Research
Mankon, Bamenda
J. Mafeni
I R Z Mankon,
P 0 Box 125, Bamenda
Y. Manjeli
Department zootechnie,
Centre Universitaire de Dschang
B.P. 96, Dschang
468
Cont'd
S.E. Mbomi
IRZ, Mankon, B P 125
Bamenda
D. Nguenga
Institute of Animal Research (IRZ)
Foumban Piscicultural Research Station
P.O.Box 255, Foumban
R.M. Njwe
Department of Animal Science
University Centre, B.P. 96, Dschang
M.Y. Nuwanyakpa
Bamenda Animal Feed Company
B.P. 428
Bamenda
Nouke
C.R.Z. Wakwa
B.P. 65, Ngaoundere- Cameroon
Ministere de I'enseignement superieur
et de la recherche scientifiqe (M.E.S.R.E.S)
Directeur Generale
Yaounde
C.W. Talbott
Heifer Project International
P.O.Box 467
Bamenda
E.N. Tambi
Institute of Animal Research
Bambui P.O.Box 80
Bamenda
E. Tendo
B.P. Mbengwi
Momo Division, Bamenda
469
Cont'd
EGYPT
M.A. El-Naga
Faculty of Agriculture
University of Alexandria
Alexandria
A.M. Nour
Department of Animal Production
Faculty of Agriculture
University of Alexandria, Alexandria
ETHIOPIA
E. Kabaija
International Livestock Centre for Africa
P.O.Box 5689, Addis Ababa
Lulseged Gebrehiwot
Institute of Agricultural Research
P.O.Box 2003, Addis Ababa
A.N. Said
International Livestock Centre for Africa
P.O.Box 5689, Addis Ababa
GHANA
D. Adomeko
Cocoa Research Institute, P.O.Box 8
TAFO (Akim)
J.E. Fleischer
Department of Animal Science
University of Ghana
Legon, Accra
470
Cont'd
A.K. Tuah
Department of Animal Science
Faculty of Agriculture
University of Science and Technology
Kumasi
KENYA
B.H. Dzowela
PANESA-ILCA, P.O.Box 46847
Nairobi
J. A. Kategile
IDRC, P.O.Box 62084
Nairobi
E.K. Odhuba
Animal Production Research Centre, Muguga
Kenya Agricultural Research Institute
P.O.Box 21, Kikuyu
MALI
S. Debrah
ILCA, BP. 60
Bamako
MALAWI
J. A. Ayoade
Department of Animal Science
University of Malawi
P.O.Box 219, Lilongwe
L.P. Nkhonjera
Department of Animal Health and Industry
Li longwe
471
Cont'd
NIGERIA
A. A. Adegbola
Department of Animal Science
Obafemi Awolowo University
Ile-Ife
O.J. Ifut
Department of Animal Science
University of Ibadan
F.I. Ogundola
Institute of Agricultural Research and Training
P.M.B. 5029, Moor Plantation
Ibadan
M.B. Olayiwole
National Animal Production Research Institute,
Ahmado Bello University, P M B 1096
Zaria
F.O. Olubajo
Department of Animal Science
University of Ibadan
Ibadan
O.B. Smith
Department of Animal Science
Obafemi Awolowo University
Ile-Ife
SENEGAL
K.P. Abassa
EISMV, BP 5077
Dakar
472
Cont'd
S. Fall
Departement de recherches sur les productions
et la sante animaIes
Institute Senegalais de Recherches
Agricole (ISRA)
Laboratoire national de I'eIevage de recherches
veterinaires (LNERV)
BP 205, Dakar- Harm
SOMALIA
Nuh Hussein Sheikh
Department of Animal Production
Faculty of Agriculture
Somalia National University
P.O.Box 801, Mogadishu
SUDAN
T.A. Mohammed
Department of Animal Nutrition
Institute of Animal Production
University of Khartoum
P.O.Box 32, Khartoum
TANZANIA
K.M. Biwi
Ministry of Agriculture
Department of Livestock Development
P.O.Box 159, Zanzibar
M. Kabatange
Livestock Production Research Institute
Private Bag
Mpwapwa
473
Cont'd
A.J. Kitalyi
Livestock Production Research Institute
Private Bag
Mpwapwa
G.I. Mlay
Department of Rural Economy
Sokoine University of Agriculture
P.O.Box 3004, Morogoro
N.A. Urio
Animal Science and Production Department
Sokoine University of Agriculture
P.O.Box 3004, Morogoro
UNITED KINGDOM
E. Owen
Department of Agriculture
University of Reading
Earley Gate, P.O.Box 236, Reading RG6 2AT
ZIMBABWE
J.M. Chesworth
University of Zimbabwe
Department of Animal Science
P.O.Box MP 167, Mount Pleasant
Harare
L.R. Ndlovu
Department of Animal Science
University of Zimbabwe
P.O.Box MP 167, Mount Pleasant
Harare
S. Sibanda
University of Zimbabwe
P 0 Box MP 167, Mt Pleasant
Harare
474



 Printed at ILCA for the African Research Network for Agricultural By-products (ARNAB).