Performance of calves in dry season feedlot according to genetic group and sex

The aim of this study was to evaluate the feedlot strategy for beef calves as an alternative during the dry season, as well as differences in the performance between genetic groups: Caracu, Nellore, crossbred Caracu x Nellore, and sex. Fifty-four calves were distributed in a completely randomized design in a 3x2 factorial scheme. The diet was formulated for an average body weight gain of 0.5 kg/day. Average daily gain (ADG), dry matter intake (DMI), and feed conversion ratio (FCR) were evaluated. The data was subjected to analysis of variance, and when significant at the 5% level, means were compared using the SNK (Student-Newman-Keuls) test. There was an interaction (p<0.05) between genetic group and sex only for ADG. Crossbred Caracu x Nellore calves male had the highest (p<0.05) gain (0.75 kg/day). Caracu males and crossbred females did not differ (p>0.05) from each other, showing gains of 0.66 and 0.63 kg/day, respectively. Caracu females had intermediate gains (p<0.05) of 0.52 kg/day. While the lowest gains were in Nellore, males and females, which did not differ from each other (p>0.05) and showed 0.42 and 0.38 kg/day, respectively. There was an effect (p<0.05) due to genetic groups, with crossbred calves showing higher (p<0.05) gain (0.70 kg/day), followed by Caracu (0.58 kg/day) and Nellore (0.41 kg/day). There was effect (p<0.05) on DMI (5.86 versus 6.58 kg/animal/day) and FCR (13.76 versus 12.39 kg of DM/kg of body weight gain) for males and females, respectively. There was also effect (p<0.05) of DMI for genetic groups, with crossbred and Caracu calves not differing (p>0.05) from each other (6.80 and 6.43 kg/animal/day), respectively, and having higher (p<0.05) intake than Nellore calves (5.91 kg/animal/day). For FCR, there was also effect (p<0.05) for genetic groups, with crossbred calves showing better (p<0.05) FCR (9.83 kg of DM/kg of gain), followed by Caracu (11.16 kg of DM/kg of gain), which in turn had better (p<0.05) FCR than Nellore (14.95 kg of DM/kg of gain). Given these results, males are superior to females in weight gain, feed conversion and also have lower feed costs in feedlot. Considering these same aspects, crossbred Caracu x Nellore calves have better performance than calves of these pure breeds. The worst performance was of the Nellore Calves.