Factors affecting birth weight and growth of Friesian x Bunaji calves

Abstract

Milking records from 1984-1989 were analysed to determine the influence of rearing method, sex of calf, season of birth, dam breed and year of birth on body weight at birth, 3, 6 and 12 months of age in Friesian x Bunaji crossbred calves. The mean weights of calves at birth, 3, 6 and 12 months of age were 22.0, 68.2, 96.7 and 127.4 kg, respectively. Sex of calf had a significant effect with male calves being heavier than the females by 1.2, 5.9 and 9.7kg at birth, 3 and 6 months of age respectively. The effect of season of birth on calf body weight was not significant except at 6 months of age when calves born during the wet season were heavier (P<0.01) than those born during the harmattan period by 9.5kg. Year of birth had a highly significant effect on calf weights from birth to yearling. The method of rearing (suckling vs bucket-fed) and dam breed had no significant influence on all the weights. The results suggest the need to develop correction factors for the standardisation of weight records when comparing dams on the basis of body weights of their calves.