Heritability Estimates and Genetic Correlation of Growth Characteristics in the Preweaning Period and Scrotal Circumference Measurement at Yearling for Angus-Nelore Beef Cattle

[摘要] - The data utilized in this work were originated from 53.938 pure and crossbred (Angus x Nelore), collected in different regions of Brazil and Argentina born from 1987 to 1998 were analyzed. The objectives of this work were to verity the heritabilities and correlation among the growing and scrotal circumference traits. The variables analyzed were the average daily gain from birth to weaning (ADGBW), days to reach 160 kg from birth to weaning (D160), weaning weight (WW) and scrotal circumference at yearling (CP). The method of restricted Maximum Likelihood and computational program MTDFREML were used with a multitrait animal model. For the growing trait, the model included the fixed effects of contemporary groups at weaning, the interaction of breeds parents of animal, the age of dam at parturition and age at weaning as covariable and the direct and maternal as random effects. For the SP the fixed effects included in the model were the linear and quadratic effects of age at yearling and weight, contemporary group at yearling and interaction composite breed sire and dam a direct animal effect as random effect. The heritability estimates were .25, .13, .23 and .21 for ADGBW, D160, WW and CP, respectively. The correlation estimates with SP were:.0,17, -.17 and .16 for ADGBW, D160, and WW respectively. These results suggest that the trait analyzed can be chosen together at the selection programs.

[学科分类] 兽医学

[关键词] animal model;average daily gain;days to gain 160 kg;maximum likelihood;weaning weight     Introdução O sistema de acasalamento entre diferentes raças é uma maneira de aumentar rapidamente a produção pecuária;fazendo uso da heterose;das diferenças aditivas e da complementaridade entre raças