Resumo

PALACIOS-ESPINOSA, Alejandro et al. Direct and maternal genetic effects for weaning weight in a Zebu beef cattle population in Cuba. Rev. mex. de cienc. pecuarias [online]. 2010, vol.1, n.1, pp.1-11. ISSN 2448-6698.

Genetic parameters for weaning weight were estimated in a Zebu beef cattle population in Camagüey province, Cuba. Data for 20,151 calves born between 1988 and 2006 were used in six variants of the statistical animal model. Contemporary groups (yearherd-season-sex) were used as a common fixed effect, and a weaning age linear regression and dam age linear and quadratic regressions as covariables. Animal random effect was common to all models, and models 2 to 6 had different combinations of genetic maternal effects, maternal permanent environmental effect and covariance between direct and maternal genetic effects. A log likelihood test showed the best model to be that which included animal random effects, maternal effects, covariance between direct and maternal effects and permanent environment. Heritability for direct (0.06 to 0.34) and maternal genetic effects (0.06 to 0.19) varied between models. Correlation between direct and maternal genetic effects varied from -0.12 ± 0.13 to -0.19 ± 0.15. The maternal permanent environmental effect explained 13 % of total variability. Heritability of weaning weight in the studied population can be overestimated when the animal model does not include maternal effects. The direct and maternal effects heritability values were low, but the relative absence of genetic antagonism between these effects indicates the possibility of moderate genetic improvement by selection.

Palavras-chave : Zebu cattle; Weaning weight; Genetic parameters; Maternal effects.

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