September 24 | The 2024 genomic evaluation results for dairy animals on the Africa-Asia Dairy Genetic Gains platform in Tanzania 0 The 2024 genomic evaluation results for dairy animals on the Africa-Asia Dairy Genetic Gains platform in Tanzania Julie M.K. Ojango1, Raphael Mrode1,2, Eliamoni T. Lyatuu1, Gilbert. T. Msuta3, Daniel M. Komwihangilo3, Neema J. Keyla1, Chinyere C. Ekine-Dzivenu1, Gebregziabher Gebreyohanes1 and Mwai A. Okeyo1 1International Livestock Research Institute (ILRI); 2Scotland’s Rural College (SRUC); 3Tanzania Livestock Research Institute (TALIRI) 2024 CGIAR Initiative on Sustainable Animal Productivity Information brief September 24 | The 2024 genomic evaluation results for dairy animals on the Africa-Asia Dairy Genetic Gains platform in Tanzania 1 Copyright information, citation, disclaimers and acknowledgements Authors: Julie M.K. Ojango, Raphael Mrode, Eliamoni T. Lyatuu, Gilbert T. Msuta, Daniel M. Komwihangilo, Neema J. Keyla, Chinyere C. Ekine-Dzivenu, Gebregziabher Gebreyohanes and Mwai A. Okeyo International Livestock Research Institute (ILRI) Suggested citation: Ojango, J.M.K., Mrode, R., Lyatuu, E.T., Msuta, G.T., Komwihangilo, D.M., Keyla, N.J., Ekine- Dzivenu, C.C., Gebreyohanes, G. and Okeyo, A.M. 2024. The 2024 Genomic evaluation results for dairy animals on the Africa-Asia Dairy Genetic Gains platform in Tanzania. Nairobi, Kenya: International Livestock Research Institute (ILRI). Cover photo: A cow in one of the farms visited during the survey (credit: ILRI/ Julie Ojango). Copyright: © 2024 ILRI. This publication is licensed for use under a Creative Commons Attribution 4.0 International License (CC BY 4.0). To view this license, visit https://creativecommons.org/licenses/by/4.0. Disclaimers: This publication has been prepared as an output of the CGIAR Initiative on Sustainable Animal Productivity. Any views and opinions expressed in this publication are those of the author(s) and are not necessarily representative of or endorsed by the CGIAR System Organization. Acknowledgements: This brief is based on the Africa-Asia Dairy Genetic Gains project implemented by the International Livestock Research Institute (ILRI) and national and international partners in Ethiopia, Tanzania, Uganda, Kenya, Rwanda, and Nepal and financially supported by the Bill & Melinda Gates Foundation. The work is part of the CGIAR Initiative on Sustainable Animal Productivity. We would like to thank all funders who supported this research through their contributions to the CGIAR Trust Fund. CGIAR is a global research partnership for a food-secure future dedicated to transforming food, land, and water systems in a climate crisis. The authors express their gratitude to all individuals and organizations that have contributed to the establishment of the national database, data capture system, and animal identification and registration system for dairy animals in Tanzania through the AADGG platform. About SAPLING: CGIAR’s Sustainable Animal Productivity for Livelihoods, Nutrition and Gender Inclusion (SAPLING) is working in seven countries focusing on livestock value chains to package and scale out tried-and- tested, as well as new, innovations in livestock health, genetics, feed and market systems. SAPLING aims to demonstrate that improvements in livestock productivity can offer a triple win: generating improved livelihoods and nutritional outcomes; contributing to women’s empowerment; and reducing impacts on climate and the environment. Its seven focus countries are Ethiopia, Kenya, Mali, Nepal, Tanzania, Uganda and Vietnam. CGIAR Initiative on Sustainable Animal Productivity Information brief https://creativecommons.org/licenses/by/4.0. https://www.cgiar.org/funders September 24 | The 2024 genomic evaluation results for dairy animals on the Africa-Asia Dairy Genetic Gains platform in Tanzania 2 Contents KEY MESSAGES .......................................................................................... 3 BACKGROUND ........................................................................................... 3 DATA .......................................................................................................... 4 GENOMIC INFORMATION ...........................................................................................4 PERFORMANCE DATA ............................................................................... 4 RESULTS ..................................................................................................... 5 GENOTYPES OF ANIMALS ......................................................................... 5 PRODUCTIVE PERFORMANCE .....................................................................................6 GENETIC TRENDS IN PRODUCTION .............................................................................7 CONCLUSION ............................................................................................ 8 REFERENCES .............................................................................................. 9 September 24 | The 2024 genomic evaluation results for dairy animals on the Africa-Asia Dairy Genetic Gains platform in Tanzania 3 Key messages o In the regions participating in the Africa-Asia Dairy Genetic Gains (AADGG) program, the dairy animals comprise an admixture with different proportions of the main European exotic genotypes (Holstein-Friesian, Ayrshire, Guernsey, and Jersey) and indigenous breeds. o The highest proportion of animals raised for dairy production in the smallholder farming systems of Tanzania (49%) include crossbred cows with 61–87.5% European exotic genes. o Since the inception of monitoring performance through the AADGG program, there has been a measurable improvement in the genetic potential for milk production. o Using the Index designed to increase milk production per cow per lactation without increasing their body size, a higher rate of genetic gain in the population can be realized compared to selection based solely on milk production. Background The Africa-Asia Dairy Genetic Gains Program (AADGG) was started in 2016 in Tanzania and Ethiopia (ILRI 2015), and in 2022, it was expanded to Kenya, Uganda, Nepal and Rwanda. The initial goal was to establish national information and communication technology (ICT) based on animal performance recording platforms and genomic evaluation pipelines. The results generated will not only be used to provide feedback information for advisory and extension support to dairy farmers and the key value chain actors for improving dairy productivity in smallholder farming systems but also to guide the development of policies to promote appropriate genetics for dairy farming systems, and improve the livelihoods of farmers in the countries (Ojango et al. 2022; Mwai et al. 2023). In Tanzania, the AADGG is implemented in 24 Local Government Authorities located in seven regions representing different milk sheds and agro-ecological zones, namely Arusha, Kilimanjaro, Tanga, Iringa, Njombe, Mbeya and Songwe (Figure 1). By December 2023, a significant number of animals, 69,881 from 33,836 herds, have been registered on the AADGG data platform (https://portal.adgg.ilri.org/tanzania). This large-scale registration is a testament to the program's impact and reach. In 2020, the AADGG program developed an index based on both the genetic and phenotypic relationship between milk yield and body weight to allow the selection of animals to be used for breeding that genetically improves milk production but keeps body weight constant (Mrode et al. 2020). Using the index, over time, the country/farmers will breed for and have access to breeding animals that produce more milk and require less feed for maintenance as selection is made against heavy body weight. This report presents the results of the 2024 genomic evaluation of animals in Tanzania. September 24 | The 2024 genomic evaluation results for dairy animals on the Africa-Asia Dairy Genetic Gains platform in Tanzania 4 Data Genomic information The cows, heifers, calves and active bulls registered on the AADGG platform (5,630 in 2018 and 2,194 in 2022) were strategically selected to include breeding bulls. A fair representation of the different breed types kept was genotyped using the 100K SNP chip to determine their breed composition and use their genomic relationships to boost the pedigree information for the genetic evaluation of the dairy herd. This process involves analyzing the animals' DNA to determine their breed composition and genetic relationships. Results from the admixture analyses confirmed a high level of breed mixes comprising four European exotic dairy breeds (Holstein-Friesian, Ayrshire, Guernsey and Jersey) and two indigenous breeds (African Taurine and Zebu) (Figure 2). The European exotic dairy percentage in each animal genotyped was computed as the sum of the estimated percentage contribution of each of the four European exotic dairy breeds. Four classes of animals were created based on their percentage of European exotic genes: ≥87.5%, 61-87.5%, 36-60% and <36%. Performance data Performance data comprising test-day milk yield and body weight of cows registered from 2016 until December 2023 was evaluated. The data consisted of 319,287 test-day records collected every month from 19,882 cows in 5,448 herds, with pedigree information comprising 69,871 records. The data was edited as follows: i) at least one parent of the animal was known or the animal had genotype information; ii) test-day milk yield was between 1 and 50 kg; iii) days in milk was between 4 and 500 days; iv) age at first calving was greater than 500 days. After editing, the total number of cows evaluated for test-day milk production was 9,540 from 3,379 farms. The body weights at milking were available for 3,121 of the animals assessed. September 24 | The 2024 genomic evaluation results for dairy animals on the Africa-Asia Dairy Genetic Gains platform in Tanzania 5 Results Genotypes of animals Bulls Genotypic information, including breed composition, was available on seventy-eight percent (78%) of the 840 bulls evaluated in Tanzania. Table 1 illustrates the proportionate breed compositions of the genotyped bulls. Among the genotyped animals, 43% had ≥87.5%, 49% had 61–87.5%%, and 8% had 36–60%% European exotic dairy breed genes, while only 1% were indigenous. A detailed listing with the genotype of the top-performing bulls and cows identified through the 2024 evaluation is presented in the report on animal performance by Ojango et al. 2024. Table 1. The main dairy breeds and the proportion of European exotic dairy genotype evident in the bulls evaluated from farms in Tanzania % European exotic dairy genotype No. of bulls (N) Main breed evident in the bulls Holstein-Friesian (% N) Ayrshire (% N) Jersey/ Guernsey (% N) *Mixed (% N) Indigenous (% N) ≥87.5% 281 34% 9% 4% 53% 61-87.5% 319 49% 19% 11% 21% 36-60% 43 21% 5% 5% 70% <36% 12 100% *Mixed: This refers to animals with a combination of the different breeds listed (Holstein-Friesian, Ayrshire, Jersey/ Guernsey) in proportions that are less than 36%. Cows Fifty-eight percent (58%) of the 9,540 cows evaluated had information on their genotypes. Among those genotyped, 37% had ≥87.5% European exotic genes, 49% had 61–87.5% European exotic genes, 11% had 36– 60% European exotic genes, and 3% had <36% European exotic genes. The proportionate representation of the cows genotyped from the different regions and the class of % European exotic genotype is presented in Table 2, while the overall representation of the various breeds evident in the cows genotyped is presented in the results from the admixture analysis, Figure 2. September 24 | The 2024 genomic evaluation results for dairy animals on the Africa-Asia Dairy Genetic Gains platform in Tanzania 6 Table 2. The number of cows genotyped from the different regions and the proportion of animals with different % of European exotic genes in each region Region No. of cows genotyped Class of % European exotic dairy genes ≥87.5% 61-87.5% 36-60% <36% Arusha 1,238 62.6% 34.3% 2% 1% Iringa 515 19% 40.8% 27% 13% Kilimanjaro 1,315 34.5% 53.4% 11% 1.2% Mbeya 839 45.2% 50.8% 3.6% 0.5% Njombe 465 42.4% 55.5% 2.2% 0 Tanga 1,153 11% 61.1% 24% 4.1% Overall 5,561 37% 49% 11% 3% A great variation in the genetic makeup of the animals reared on the farms is evident. Across the different regions of Tanzania, Arusha has the highest proportion of animals, with ≥87.5% of European exotic dairy breeds in their genetic makeup (Table 2). Notably, 49% of the animals reared have 61–87.5% of European exotic genes of different combinations. The combinations of the European exotic dairy genes in the population comprise a mixture of the main dairy breeds (i.e. Holstein-Friesian, Ayrshire, Jersey and Guernsey) as illustrated in the levels of admixture in the cattle genotyped (Figure 2). Figure 2. Results of the admixture analysis of cows in Tanzania illustrate the combination of genotypes present in the dairy cattle population. Productive performance Milk yield and body weight Figures 3 (milk) and 4 (body weight) illustrate the differential levels of milk production and body size of animals with different proportions of European exotic genes from the various regions of the country. September 24 | The 2024 genomic evaluation results for dairy animals on the Africa-Asia Dairy Genetic Gains platform in Tanzania 7 Figure 3. The average test-day milk yield (kg) for animals with different proportions of European exotic genes ≥87.5%, 61-87.5%, 36-60%, and <36% from the AADGG project regions in Tanzania. Figure 4. The average body weight of animals (kg) with different proportions of exotic genes in the AADGG project regions of Tanzania. In all regions except Arusha, milk production varied depending on the proportion of exotic genes in the animals. The highest average milk production by all breed combinations is in the Mbeya region. The results of the performance of the individual animals evaluated from each farm are available in a separate information brief (Ojango et al., 2024). The information in the separate brief primarily enables extension personnel to share the results and provide advice on changes to be made in breeding animals with individual farmers. Genetic trends in production Figure 5 illustrates the genetic trend in milk production and the trend in gains attained using the index developed for the evaluation of animals in Tanzania in 2020 (Mrode et al. 2020). The results demonstrate that genetic improvement in milk yield and the index were realized during the project period (i.e. from 2014 to 2020). Though fewer in number, the younger animals in the population born since 2018 have better productive potential. https://cgspace.cgiar.org/items/90f65829-104c-4d82-ae3c-ae60409e5b39 September 24 | The 2024 genomic evaluation results for dairy animals on the Africa-Asia Dairy Genetic Gains platform in Tanzania 8 Figure 5. The genetic trend in milk production for cows born from 2012 to 2020 against the trend in the Index–2024. The trend in the Index-2024 for animals with different proportions of European exotic genes born in the country is presented in Figure 7. The highest positive trend is for animals with >87.5%, followed by those with 61–87.5% European exotic genes. Animals with <36% have a fluctuating trend in the index. Figure 6. Trend in the Index-2024 for cows with different proportions of European exotic genes born from 2012 to 2020. Conclusion There is a positive genetic trend in the productivity of dairy animals raised in the smallholder farming systems participating in the AADGG program in Tanzania. % European Exotic Genes September 24 | The 2024 genomic evaluation results for dairy animals on the Africa-Asia Dairy Genetic Gains platform in Tanzania 9 References International Livestock Research Institute (ILRI). 2015. African Dairy Genetic Gains program: More productive cattle for Africa’s smallholders. ILRI Project Profile. Nairobi, Kenya: ILRI. http://hdl.handle.net/10568/69179. Lyatuu, E.T., Komwihangilo, D., Msuta, G., Keyla, N., Okeyo, M., Ojango, J. and Gebreyohannes, G. 2023. Unlocking total factor productivity of smallholder dairy farmers in Tanzania. Tanzania Journal of Agricultural Sciences 22: 338-345. https://www.ajol.info/index.php/tjags/article/view/266581. Mrode, R., Ojango, J.M.K., Chinyere, E. and Mwai, A.M. 2020. The platform for Africa Dairy Genetic Gain (ADGG) 2020, New Index for dairy cattle in Tanzania and guidelines on its use. ILRI, Nairobi, Kenya https://africadgg.wordpress.com/wp-content/uploads/2020/08/adgg-tzn-index-2020.pdf. Mwai, A., Gebreyohanes, G., Ojango, J.M.K., Mrode, R., Chinyere, E., Jabes, Y., Kipkosgei, G., Mogaka, D., Abdulkadir, Kelya, N., Agasi, H., Meseret, S., Eliamoni, L. and Kemp, S. 2023. The Africa Asia Dairy Genetics Gains (AADGG) Platform. ILRI project profile. Nairobi, Kenya: ILRI. Ojango, J. M. K., Okeyo, A. M., Mrode, R., Chinyere, E., Gebreyohanes, G., Rao, J., Meseret, S., Mogaka, D., Lyatuu, E., Komwihangilo, D., Msuta, G., Kahumbu, S., Gibson, J. P., and Kemp, S. 2022. Bridging the gap in data from smallholder dairy systems; The Africa Dairy Genetic Gains (ADGG) Data platform. In 12th World Congress Genetics Applied to Livestock Production. Rotterdam, The Netherlands. Ojango, J.M.K., Mrode, R., Lyatuu, E.T., Msuta, G., Komwihangilo, D.M., Keyla, N., Ekine-Dzivenu, C.C., Gebreyohanes, G. and Okeyo, A.M. 2024. Genetic evaluation results explained for extension support. Tanzania Information Brief. Nairobi, Kenya: ILRI https://hdl.handle.net/10568/148867. September 24 | The 2024 genomic evaluation results for dairy animals on the Africa-Asia Dairy Genetic Gains platform in Tanzania 10 Contact: Julie Ojango, senior scientist, , j.ojango@cgiar.org SAPLING Initiative lead, Isabelle Baltenweck, I. Baltenweck@cgiar.org SAPLING Initiative deputy lead, Rekik Mourad, M.Rekik@cgiar.org CGIAR is a global research partnership for a food-secure future. CGIAR science is dedicated to transforming food, land, and water systems in a climate crisis. Its research is carried out by 13 CGIAR Centers/Alliances in close collaboration with hundreds of partners, including national and regional research institutes, civil society organizations, academia, development organizations, and the private sector. www.cgiar.org We would like to thank all funders who support this research through their contributions to the CGIAR Trust Fund: www.cgiar.org/funders. To learn more about this Initiative, please visit this webpage. To learn more about this and other Initiatives in the CGIAR Research Portfolio, please visit www.cgiar.org/cgiar-portfolio © 2024. International Livestock Research Institute. Some rights reserved. 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