Interacción genotipo x ambiente sobre el peso al destete de bovinos nelore en Brasil

The objectives of this study were to evaluate the genotype x environmental interactions and estimates of genetic parameters for weaning weight (P205) in two Brazilian regions. Weights of Nellore calves (n= 46 390) were collected over a 27 year period, on 398 farms in the regions of Pantanal and Goiás. The MTDFREML program was used for estimation of variances components. The statistical model has a fixed effect of contemporary groups (farm, sex, season and year of birth) and age of dam at parturition (quadratic); random effects of direct genetics effects, maternal genetic effects and permanent environmental effects. The genetic correlation for weaning weight in Pantanal and Goiás was 0.61, evidence of the genotype x environmental interaction. The direct and maternal heritabilities and genetic trend were 0.34, 0.07 and 8.4 kg and 0.27, 0.09 and 11.8 kg. for animals raised in Pantanal and Goiás, respectively.