Body weights at birth, 90 days, 180 days and 1 year of age were analysed in 620 calves, the offspring of sires of the Friesian, Jersey and Simmental breeds, and of dams of three indigenous zebu breeds, namely Barka, Boran and Horro, at four diverse locations in Ethiopia.
Breed of sire, breed of dam and location all significantly affected weight. Progeny of Friesian and Simmental sires were similar in weight but both were heavier than the progeny of Jersey sires, their weight being, respectively, 25·0,24·9 and 21·2 kg at birth; 88·0, 84·6 and 74·9 kg at 90 days; 151·7, 150·6 and 135·4 kg at weaning at 180 days; and 220·6,224·8 and 193·3 kg at 365 days. Barka crosses were heaviest and Horro lightest. Mean weight for progeny from Barka, Boran and Horro dams was, respectively, 24·0, 24·6 and 22·5 kg at birth; 85·2, 83·8 and 78·5 kg at 90 days; 149·6, 148·0 and 140·1 kg at 180 days; and 233·7, 208·1 and 196/9 kg at 365 days. Dam breed × location interaction was significant except at birth, and sire breed × dam breed and sire breed × location interaction were significant at 90 days of age. In a comparison of Friesian and Simmental, the Friesian sires interacted relatively more favourably with the Barka dams, and the Simmental with the Boran. The Jersey was also relatively better with the Boran crosses, compared with either the Barka or the Horro crosses. By 1 year of age Jersey crosses were at a relative (but insignificant) advantage in body weight at the hottest location.