Banjaw K, Haile-Mariam M
Alemaya University of Agriculture, Dire Dawa, Ethiopia.
Trop Anim Health Prod. 1994 Feb;26(1):49-57. doi: 10.1007/BF02241133.
Birth (4,197) and weaning (2,441) weight data on Boran, F1 Boran Friesian and three quarter Friesian calves as well as adjusted one-year (390), 2-year (177) and 3-year (364) weights on Boran cattle were analysed to estimate the influence of genetic and environmental factors. Boran, F1 and three quarter calves weighted 25.2, 25.4 and 25.7 kg at birth and 157.5, 176.7 and 179.9 kg at weaning, respectively. All factors included in the analysis and their interaction had significant effects on both traits with the exception of the effect of season of birth and its interaction with breed group on birth weight. Weight of Boran cattle at one-, 2- and 3-years of age were 179, 269 and 338 kg, respectively. Heritability values calculated on the basis of paternal half-sibs were 0.32, 0.24, 0.48, 0.29 and 0.24 for birth, weaning, one-year, 2-year and 3-year weights, respectively. The study indicated that F1 crosses were 12.2% heavier at weaning than Boran calves. Of the environmental factors considered, year of birth was found to be the major source of variation mainly due to variation in the amount of rainfall between years.
对博拉牛、F1博拉-弗里西恩杂交牛和四分之三弗里西恩杂交牛犊的出生体重（4197例）和断奶体重（2441例）数据，以及博拉牛一岁（390例）、两岁（177例）和三岁（364例）的校正体重数据进行了分析，以估计遗传和环境因素的影响。博拉牛、F1杂交牛和四分之三杂交牛犊出生时的体重分别为25.2千克、25.4千克和25.7千克，断奶时的体重分别为157.5千克、176.7千克和179.9千克。分析中包含的所有因素及其相互作用对这两个性状均有显著影响，但出生季节及其与品种组对出生体重的相互作用除外。博拉牛一岁、两岁和三岁时的体重分别为179千克、269千克和338千克。基于父本半同胞计算的遗传力值，出生体重、断奶体重、一岁体重、两岁体重和三岁体重分别为0.32、0.24、0.48、0.29和0.24。研究表明，F1杂交牛断奶时比博拉牛犊重12.2%。在所考虑的环境因素中，出生年份被发现是主要的变异来源，主要是由于年份间降雨量的变化。
