Características pre-destete de becerros Brahman en un sistema doble-próposito tropical

The objective of this study was to analyze factors associated with pre-weaning growth traits (e.g., weight and linear body measurements) and neonatal weakness in graded Red (RB, n=86) and Grey Brahman (GB, n=33) calves. Observed parameters included birth weight (BW), weight at 210-d (W210), average daily gain from birth to 210-d (ADG), and multiple linear body measurements. At birth, males were heavier (31.6 ± 0.9 kg 28.5 ± 0.8 kg; P<0.002) than females, differences due to sire (P<0.001) were observed, and calves experiencing NW tended to be lighter than normal calves (29 ± 1.1 vs 31.2 ± 0.6 kg; P<0.06). At 210-d, males were heavier than females (124.7 ± 3.2 vs 111 ± 3.4 kg; P<0.007), cows in their second and fourth parities had the heaviest (P<0.001) calves. Heavier W210 (122.5 ± 3.4 vs 113 ± 3.1kg; P<0.01) and greater ADG (0.451 + 0.01 vs 0.388 + 0.01 kg/d; P<0.001) were found in calves born during dry season compared to those born during rainy season. Calves from second and fourth parity dams had greatest (P<0.01) ADG. Both at birth and 210-d., all linear body traits and body weight were highly correlated (P<0.001). Calves experiencing NW had reduced W210 (113 ± 4 vs 122 ± 2.6 kg; P<0.05) thorax circumference, hip height and dorsal length (P<0.001) compared to normals. Occurrence of NW was greater in RB than GB (P<0.005). Three sires were found to be associated with NW (P<0.005).