ESTIMATIVAS DE PARÂMETROS GENÉTICOS PARA CARACTERÍSTICAS DE CRESCIMENTO DE CORDEIROS MESTIÇOS SUFFOLK

Abstract

The aim of this study was to estimate the heritability and genetic correlation coefficients between weights at birth (BW) and weaning (WW) in Suffolk crossbred lambs, which belonged to an experimental herd. Thus, four different animal models were fitted, including the direct additive genetic effect (Model 1), the direct additive genetic and maternal permanent environmental effects (Model 2), the direct additive, permanent environmental and maternal genetic effects (cova,m=0) (Model 3), and in Model 4, in addition to those in Model 3, cova,m≠0 was considered. After comparing the models through the likelihood ratio test (LRT), Model 3 was chosen as the most appropriate, being the heritability estimates low in magnitude for BW and WW, equal to 0.08±0.009 and 0.24±0.17, respectively, which indicates low possibility of response to direct selection. Likewise, the correlation coefficient between these traits, 0.43±0.39, implies low possibility of correlated response. The inclusion of maternal effects is necessary for the accurate estimation of genetic parameters for the evaluated traits.

Keywords

• body weight
• genetic correlation
• heritability
• model comparison