Milk yield and composition of primiparous recipient cows influence the performance and carcass ultrasonography of Nellore calf

ABSTRACT This study investigates the influence of the breed of primiparous recipient cows on milk yield and composition during the lactation stage, as well as evaluating the carcass and performance characteristics of their calves at weaning. The experiment was conducted in a commercial Nellore herd with two groups of primiparous recipient beef cattle, Nellore (n？=？11) and ？ Angus？×？Nellore (n？=？11). Variables were measured monthly from birth to weaning. Days in milk affected milk intake and composition. There was an effect of the interaction of breed and time on milk fat, protein and lactose, measured in g/kg of milk. Calves from Angus primiparous cows had greater body weight, average daily gain (ADG), longissimus muscle area (LMA) and longissimus weight-to-width ratio than others, since those traits are associated with milk yield. In contrast, considering area/100？kg, backfat and marbling, the Nellore cows delivered similar calves to the Angus cows, due to the better quality of their milk. Milk intake was positively correlated with ADG, BW and LMA, but negatively correlated with milk protein, fat and lactose. The nutrients in milk were positively correlated with milk intake, and body weight was positively correlated with LMA, weight-to-width ratio, backfat, milk intake and ADG