Haile-Mariam M, Banjaw K, Gebre-Meskel T, Ketema H
Alemaya University of Agriculture, Dire Dawa, Ethiopia.
Trop Anim Health Prod. 1993 Nov;25(4):239-48. doi: 10.1007/BF02250878.
Data collected on number of services per conception (NSC), age at first calving (AFC), calving interval and calf pre-weaning mortality rate of Boran cattle and their Friesian crosses were evaluated. The NSC was 1.81, 1.61 and 1.69 for Boran, F1 Boran-Friesian and three-quarter Friesian heifers respectively. The AFC varied from 31.5 months in the F1 crosses to 46.8 months in the Boran heifers artificially inseminated with Friesian semen. The mean calving intervals were 465, 552, 525 and 487 days for Boran cows naturally mated to Boran and Friesian bulls, Boran and F1 cows artificially inseminated with Friesian semen respectively. The preweaning calf mortality rate was 3.4% and was significantly influenced by parity, sex and interaction of breed with year of birth. Year as well as season had in general significant effects on the traits considered. However, the variation between mating or breeding groups was also large and it was in favour of the F1 crosses.
对收集到的关于博拉牛及其与弗里斯兰牛杂交后代每次受孕服务次数（NSC）、首次产犊年龄（AFC）、产犊间隔和犊牛断奶前死亡率的数据进行了评估。博拉牛、F1代博拉牛 - 弗里斯兰牛和四分之三弗里斯兰牛小母牛的NSC分别为1.81、1.61和1.69。AFC在F1杂交后代中为31.5个月，在使用弗里斯兰精液人工授精的博拉牛小母牛中为46.8个月。对于自然与博拉牛和弗里斯兰公牛交配的博拉牛母牛、分别使用弗里斯兰精液人工授精的博拉牛和F1代母牛，平均产犊间隔分别为465天、552天、525天和487天。断奶前犊牛死亡率为3.4%，且受胎次、性别以及品种与出生年份的相互作用显著影响。年份以及季节总体上对所考虑的性状有显著影响。然而，交配或繁殖组之间的差异也很大，且有利于F1杂交后代。
