Productive efficiency of cows primiparous aberdeen angus of the body size and milk production levels

Abstract

Assessment of the productive efficiency of 30 primiparous Aberdeen Angus cows of different body sizes, classified at calving as heavy (375±10.5 kg) or light (283±7.7 kg), and different total milk-yield levels, classified as high (868±24.5 kg) or low (547±18.3 kg). Heavy cows were superior in weight at calving and weaning, but there were no differences in milk yield and weight at birth and weaning of calves. Heavy cows were less efficient than light cows in the production of kilograms of calves per 100 kg of cows at calving and at weaning. High-producing cows were heavier at calving and had heavier calves at birth and weaning, but did not differ between the milk-yield levels for the variation in daily weight. The variation in daily weight of the calves was greater from high-producing cows. High-producing dairy beef cows were more efficient at weaning, and their calves required less milk to produce one kilogram of live weight.