Heritabilities of pre-weaning traits in a multibreed beef cattle herd fitting models with or without a sire genotype x dam genotype interaction

Abstract

Animal breeders are concerned with unbiased estimation of genetic parameters, since it also has aninfluence on the accuracy of predicted breeding values. In many studies, additive genetic variances are often eitherover- or under-estimated. In multibreed (crossbred or composite breeds) evaluations these parameters aresometimes overestimated when it is assumed that non-additive differences are absent. Estimates will especially bebiased if the correct covariance structure is not employed ( Komender & Hoeschele, 1989), such as where there is anon-random distribution of sires across genotypes, i.e. if certain sires are more frequently used within certaingroups than in others. Animal (or sire) effects are then confounded with group effects, thus resulting in the biasedestimates. The objective of this investigation was to compare heritabilities where the sire genotype x dam genotypeinteraction was fitted into the model to account for non-additive variances and the non-random distribution of siregenotypes compared to where it was not fitted.