Genetic parameters and annual trends for 305-Day milk yield of Bos taurus dairy cattle breeds in Kenya Ilatsia ED*, Migose SA1, Magothe TM2, Muasya TK, Kahi AK1 Kenya Agricultural Research Institute, PO Box 25, 20117 Naivasha, Kenya National Animal Husbandry Research Centre
*E-mail: evansilatsia@yahoo.com
1Animal Breeding and Genetics Group, Department of Animal Sciences, Egerton University, P.O. Box 536, 20107, Njoro, Kenya. 2Livestock Recording Centre, Ministry of Livestock and Fisheries Development, P. O. Box 257, 20117, Naivasha, Kenya. Abstract The objective of this study was to estimate genetic parameters and annual trends in 305-d milk yield (MY) of Bos taurus dairy cattle breeds in Kenya. The B. taurus breeds considered were Holstein Friesian (F), Ayrshire (A), Jersey (J) and Guernsey (G) kept for milk production on various farms. Data were obtained from various farms across the country which is usually stored at the Livestock Recording Centre (LRC). Genetic parameters were estimated by fitting a repeatability animal model and the best linear unbiased prediction (BLUP) procedure was used to estimate breeding values for MY for cows born between 1979 to 2000. All the analyses were conducted using the DFREML computer programme. Breeding values were averaged by year of birth to give the annual genetic trends. Annual environmental trends were obtained by averaging herd-year-season of calving least square solutions within year of calving. Heritability estimates for F, A, J and G breeds were 0.16, 0.13, 0.12 and 0.35, respectively. Repeatability estimates were 0.33, 0.38, 0.84 and 0.61 for F, A, J and G breeds respectively. The average genetic progress for the F breed was close to zero while the regressions indicated an overall rate of increase of 1.5kg, 10.8kg and 9.8kg for A, J and G, respectively. Environmental trends were generally undesirable for all the breeds suggesting fluctuation in feed availability and other management related practises. There is the potential to realise steady genetic progress if sound genetic improvement strategies are adopted. Top Keywords Annual trends, Bos taurus breeds, Genetic parameters, Kenya, 305-d milk yield. Top |