Non genetic effects on productive traits in Nellore cattle from Northern Brazil

Abstract

This study was carried out to investigate the effects of environmental factors that influence the traits of adjusted weight at 205 (P205) to 365 (P365) and 550 (P550) days old, and days to gain 160 kg pre-weaning (D160) and 240 kg (D240) post-weaning. The data set was provided by Brazilian Association of Zebu Breeders - ABCZ and collected between 1997 and 2007, in 758 herds from Northern of Brazil. The general statistical model included the fixed effects of herd, year and month of birth, sex of calves, the covariate of age at calving (linear and quadratic), and the random effect of sire. The mean were 165.34 ± 18.08 kg, 247.67 ± 24.15 kg, 410.62 ± 36.47 kg, 410.62 ± 36.47 kg, 336.76 ± 24.97 days and 387.08 ± 43.56 days for P205, P365, P550, D160 and D240, respectively. All effects were significant (p<0.001). The age at calving effect (linear and quadratic) influenced the traits of weight at 205 days and days to gain 160 kg. Due to the significance of environmental factors on pre-and post-weaning traits, these effects should be considered in the selection process of Nellore cattle from Northern Brazil. Keywords: Age at calving, environment, zebu