This study was carried out to evaluate the effect of additive genetic-maternal covariance on estimates of genetic parameters and on the prediction and ranking of breeding values of Tabapuã animals. Records of 19,646, 14,276, 10,663, and 6,176 birth weights and weights at 205, 365, and 550 days of age were used in univariate animal model analysis using MTDFREML software, including or not the additive genetic-maternal covariance in the models. The additive genetic-maternal covariance estimates were, respectively, -0.08, -0.22, -0.10, and 0.34 for birth weight and weights at 205, 365, and 550 days of age. The direct and maternal heritability estimates including the additive direct-maternal covariance were, respectively, 0.31, and 0.10; 0.31 and 0.20, and 0.17; and 0.20 and 0.06; and 0.17 and 0.01 for birth weight and weights at 205, 365, and 550 days of age, while without the additive direct-maternal covariance those values were, respectively, 0.31 and 0.09; 0.18 and 0.14; 0.20 and 0.05; .18 and 0.02. Rank correlation between predicted breeding values from two models for birth weight and weights at 205 and 550 days of age were, respectively, 0.999, 0.992, 0.999, and 0.998. For maternal genetic values, these estimated rank correlations were, respectively, 0.995, 0.985, 0.992, and 0.771. The inclusion of additive genetic-maternal covariance in the analysis did not affect genetic parameter estimates and had a very small effect on breeding values ranking of Tabapuã animals.
beef cattle; Tabapuã; additive-maternal covariance; genetic evaluation
