Variance components for weight and type traits in a multiracial population of meat sheep in eastern Antioquia

The objective of genetic evaluation is to provide a tool to identify and select genetically superior animals that transmit desirable traits to their offspring, improving flock productivity over generations. This study aimed to evaluate genetic and phenotypic parameters for weight and type traits in a multiracial meat sheep population in eastern Antioquia, using Bayesian inference analysis. The study was conducted at two farms: “Ovinos de la Sierra” in La Ceja del Tambo, and “El Charrascal” in Copacabana, Antioquia, Colombia. Animals from various racial groups were evaluated, focusing on productive traits, namely birth weight (BW) and adjusted weaning weight at 90 days (AW90), together with twelve phenotypic traits. A single-trait animal model was applied, incorporating the fixed effects of breed type, calving type, sex, and live weight. Variance components and genetic parameters and expected breeding values were estimated. The mean (± standard deviation) for BW and AW90 were 3.655 ± 0.806 kg and 19.610 ± 5.181 kg, respectively. Direct and maternal heritability estimates for BW were 0.6734 and 0.2963, and for AW90 were 0.9323 and 0.0670. Among phenotypic traits, thoracic perimeter showed the highest heritability, followed by rump length, while the lowest heritability estimates were for withers width and rump width. All estimates were convergent, except maternal and phenotypic estimates for BW. Proper data recording is essential for evaluating genetic and phenotypic parameters, and Bayesian analysis provides reliable variability through posterior distributions, supporting the grouping of animals by age and production group for uniform data.