EFEITOS DA INCLUSÃO OU NÃO DA COVARIÂNCIA GENÉTICA DIRETA-MATERNAL NO MODELO E DOS VALORES REAIS DAS (CO)VARIÂNCIAS SOBRE SUAS ESTIMATIVAS PARA PESO À DESMAMA EM BOVINOS DE CORTE

• Main Authors: JORGE LUIS FERREIRA, ARCADIO DE LOS REYES BORJAS, ROBERTO CARVALHEIRO, RAYSILDO BARBOSA LÔBO
• Format: Article
• Language: English
• Published: Universidade Federal de Goiás 2011-09-01
• Series: Ciência Animal Brasileira
• Subjects: cattle; direct-maternal genetic correlation; co-variance estimates; simulation.
• Online Access: http://www.revistas.ufg.br/index.php/vet/article/view/5503/9669
• ISSN: 1518-2797; 1089-6891

This study aimed to compare estimates of (co)variances considering the effect of direct maternal genetic correlation (-0,50; -0,25; +0,25; +0,50); the ratios between the direct and maternal genetic variances (75:75; 50:100; 100:50) and two models which included (M2) or not (M1) the direct maternal genetic covariance. Stochastic simulation of twenty replicates of a closed and randomly mated herd of cattle was carried out for twenty years of selection. The base population was not related, nonselected and randomly sampled. (Co)variance estimates were obtained under single trait animal model using MTDFREML application. The model was not significant on estimates of maternal permanent environmental variance. The genetic direct-maternal correlation influenced all (co)variance estimates significantly (P<0,05). The ratios of genetic direct and maternalvariances significantly affected (P<0,05) only estimates of genetic direct and maternal variances. Regarding negative direct-maternal genetic correlation, M1 underestimated direct and maternal variances while overestimated both when that correlation was positive. Reliable and accurate (co)variance estimates for weaning weight in beef cattledepend on the adequacy of the model as well as their actual values.