Abstract

Estimation of genetic parameters and variance components for growth traits in Romosinuano cattle in the Colombian humid tropics

(Co)variance components and genetic parameters were estimated for body weights of a Romosinuano herd located in Sinú Valley, Cordoba, Colombia. Restricted maximum likelihood methods were used with a univariate animal model for birth weight, weaning weight (270 days), 16-month weight (480 days), weaning daily gain, and postweaning daily gain. Models included random animal direct and maternal genetic effects, maternal permanent environmental effect (c2), and sexyear- month of birth and age of dam, as fixed effects. Estimates of direct effect for birth weight, weaning weight, 480-day weight, weaning daily gain, and post-weaning daily gain were: 0.25 ± 0.0001, 0.34 ± 0.063, 0.33 ± 0.066, 0.32 ± 0.062, and 0.17 ± 0.052, respectively. Estimates of direct maternal genetic effects were low and ranged from 0.06 ± 0.003 for birth weight to 0.20 ± 0.054 for weaning daily gain. The genetic correlations between direct and maternal genetic effects were negative and low for 480-day weight (-0.05 ± 0.219) and showed values of -0.37 ± 0.007, -0.34 ± 0.133, -0.33 ± 0.135, and -0.38 ± 0.232 for birth, weaning weight, weaning, and post-weaning daily gain, respectively. Permanent environmental maternal effects were not significant; the highest values were found for weaning weight, and weaning daily gain (0.086 ± 0.031 and 0.078 ± 0.031, respectively). We conclude that direct and maternal effects should be included in a selection program for all of these traits, and also that selection of weaning weights would be the most productive way to improve performance in Romosinuano cattle.

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