Performance of calves sired by straightbred Nellore, Canchim and crossbred (F1) Charolais x Nellore and Piedmont x Nellore bulls

The objective of this study was to compare birth weight (BW); weaning weight (WW) and average daily gain from birth to weaning (ADG) of calves by Nellore cows and sired by straightbred Nellore and crossbred 5/8 Charolais + 3/8 Zebu (Canchim) bulls - Data 1, and straightbred Nellore and crossbred (F-1) 1/2 Charolais + 1/2 Nellore and 1/2 Piedmont + 1/2 Nellore bulls - Data 2. The analysis of variance were realized by the least square method, for each data separately, with models that included the effects of genetic group of calf, rear and month of birth, sex of calf and age of cow at calving. For Data 1, the crossbred 1/2 Canchim + 1/2 Nellore calves were heavier and gained more weight than the Nellore; the least square means For BW (kg), WW (kg) and ADG (kg/day) were equal to 28.6+/-0.1, 181+/-1 and 0.565+/-0.003 for Nellore and 29.7+/-0.1, 191+/-1 and 0.599+/-0.004 for crossbred calves. For Data 2, the crossbred sires, on the average, produced heavier calves that gained more than those sired by straightbred Nellore bulls, and the 1/2 Charolais + 1/2 Nellore sires produced heavier calves at birth than the 1/2 Piedmont + 1/2 Nellore ones. The least square means were, in the same order, 27.9+/-0.01, 183+/-1 and 0.579+/-0.003 for the Nellore calves, 29.7+/-0.1, 191+/-1 and 0.599+/-0.003 for the crossbred 1/4 Charolais + 3/4 Nellore calves, and 28.9+/-0.2, 191+/-1 and 0.599+/-0.003 for the 1/4 Piedmont + 3/4 Nellore calves, respectively. The results indicate that there is an advantage to using bulls of the new synthetic breed (5/8 Charolais + 3/8 Zebu) and crossbred bulls (1/2 Charolais + 1/2 Nellore and 1/2 Piedmont + 1/2 Nellore) crossbred bulls, compared to Nellore bulls, when mated to Nellore cows, for preweaning growing traits.