Direct and Maternal Genetic Parameter Estimates for Individual Birth Weight, Weaning Weight and Probe Weight of Yorkshire and Landrace Pigs

The purpose of this research was to estimate genetic parameters for individual birth weight, weaning weight and probe weight of purebred Yorkshire and Landrace swine in Canada. Data were collected from two large and related breeding herds from Quebec and Manitoba from 2003-2015. Fixed effects of sex, contemporary group, covariates of age at weighing and the random effects of direct and maternal genetic effects, common litter effects and residual errors were modelled using ASReml. The model which included all three random effects was determined to be the best fit to the data. The direct heritability increased with age as a result of the maternal influence on that animal decreasing. Strong direct genetic correlations and maternal genetic correlations were found were found between birth weight and weaning weight. Based on the estimates of genetic parameters, individual early growth performance should be evaluated and considered in genetic evaluations and breed selection programs.