Environmental effects on variation in growth and reproductive performance of Boran cattle in ASAL of Kenya.

摘要

Environmental effects influencing the growth and reproduction performance of Kenya Boran cattle were evaluated using 4502 growth and 2681 reproductive performance records from a large-scale commercial ranch and a national beef research station in the arid and semiarid lands of Kenya. Growth traits included birth (BW), weaning (WW), 12 month (12W), 18 month (18W) and 24 month (24W) weights. Reproductive traits were age at first calving (AFC), pooled calving interval (CI) and CI in the first four parities (CI1, CI2 and CI3). Sex significantly affected all growth traits, parity of dam influenced BW, WW, 18W and 24W. Year-season effects significantly influenced BW, 12W, 18W and 24W. Age at weighing affected 12W, 24W and 18W. All CIs were significantly affected by year of calving. Herd-year-season of birth and calving, and AFC as a covariate were significant for AFC, CI1, CI2 and CI. Mean estimates for BW, WW, 12W, 18W and 24W were 27.99 kg, 184.55 kg, 145.39 kg, 178.82 kg and 220.98 kg, respectively. For AFC, CI1, CI2, CI3 and pooled CI, they were 1187.74 days, 496.62 days, 460.14 days, 442.57 days and 476.91 days, respectively. This study shows environmental influence on performance of Kenya Boran cattle. Effective genetic improvement would be feasible by accounting for them in genetic evaluation programmes..