Genetic evaluation of milk yield of Bos taurus dairy breeds in Kenya

Abstract

The objective of this study was to quantify the rate of genetic progress in 305-d milk yield (MY) in Bos taurus dairy cattle breeds. The Bos taurus breeds considered were Holstein Friesian (F), Ayrshire (A), Jersey (J) and Guernsey (G) kept for milk production in small, medium and large scale Kenyan farms. Data were obtained from the Livestock Recording Centre (LRC) which is mandated to analyse data from the Dairy Recording Services of Kenya collected from various farms across the country and make the results available for use in making selection decisions. The best linear unbiased prediction (BLUP) fitting a repeatability animal model was used to estimate breeding values for MY for cows born between 1980 to 2000. Breeding values were averaged by year of birth to give the genetic trends. Environmental trends were obtained by averaging herdyear-season of calving least square solutions within year of calving. The average genetic progress for the F breed was close to zero while the regressions indicated an overall rate of increase of 1.5 kg, 10.8 kg and 9.8 kg 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.