The aim of this study was to compare the selection criteria based on the average daily gain (ADG) and days to achieve 160 kg (D160) on pre-weaning of Guzerat cattle. Database on weight gains provided by the Brazilian Association of Zebu Cattle Breeders (ABCZ) was used. The estimated genetic parameters and breeding values was obtained by the Restricted Maximum Likelihood Method, using a uni-trait animal model, with equations of mixed models. The model included the fixed effect of contemporary group, genetic additive direct and permanent environment, as random effects, beyond the residual error. The means for D160 and ADG were 270.5 days and 642.3 g, respectively. Spearman's correlations for pre-weaning ADG and D160 (D160P), and ADG and D160P corrected for contemporary group effect (D160Pc), were equal to 0.92 and 0.94, respectively. The selection for D160P would favor sires that produced superior and less variable progenies. The correction of D160 to the contemporary group effect made this trait more efficient to identify more uniform sires. Sires classification changed according to the adopted selection criterion, ADG or D160P, mainly at the end points, where animals should be selected and rejected.
average daily gain; days to achieve 160 kg on pre-weaning; harmonic mean; uniform offspring
