ESTIMATION OF GENETIC PARAMETERS FOR WEANING WEIGHT IN WHITE OREJINEGRO CATTLE IN THE COLOMBIAN NORTHWEST

Objective. To estimate the direct and maternal additive genetic components of variance for weaning weight in native cattle, Blanco Orejinegro (BON). Materials and methods. 356 records of the animal nucleus pure breed BON belonging to Vegas de la Clara farm, property of Universidad de Antioquia, between the years 1988 to 2007 were used. Analysis was made using an animal model including sex and weaning time fixed effects, and as covariable weaning age and as random effects, direct genetic, maternal genetic, permanent environmental and residual. Results. Mean weaning weight was 196.3 ± 31.4 kg at a mean age of 271.8 ± 13.5 days. 21 inbreeding animals had an inbreeding coefficient of 24.5%. Direct and maternal heritability was of 0.63 ± 0.36 and 0.22 ± 0.19 respectively, with a correlation between the direct and maternal effect of -0.78 ± 0.21. Conclusions. According to these results, genetic variability exists in the nucleus BON for this characteristic.