Estimation of genetic parameters for growth traits in Canchim cattle with finite models

The objectives of this work were to evaluate different models, regarded to considered maternal effects, for growth traits and to estimate genetic parameters for these traits in Canchim breed bovine, by one, two and multitrait analyses. The weight traits at birth, at weaning, standardized weight for 12, 18, 24 and 30 months of age in males and females, and mature female weight were analyzed using four models with random effects added in sequence. Maternal effects influenced birth weight at 2 years of age and weaning weight was the most affected by maternal effects. Direct heritability estimates obtained by two- and multitrait analyses were higher than those obtained through one-trait analyses. Estimates of direct genetic effect heritability obtained using multi-trait analyses were 0.39 for weight at birth; 0.31 for weight at weaning; 0.29 for weight at 12 months of age; 0.28 for weight at 18 months of age; 0.26 for weight at 24 months of age; 0.30 for weight at 30 months of age and 0.38 for weight at mature age. Genetic correlations estimated among weights at early ages and mature weight were high, above 0.79. Selection based on growth traits at any age can promote intermediate genetic gains on the body weight of Canchim breed animals at all standard ages, including weight at birth and at mature age of females. It is important to consider in the analyses the weights previous to selection to estimate genetic parameters for weights after selection. Multitrait analyses is the best indicated.

beef cattle; genetic correlation; heritability; multitrait analyses; weight at standard age