The contribution of central boar performance testing to genetic improvement of the Queensland pig population

Abstract

In Queensland, stud pig breeders can submit boars to a performance testing station where theft breeding values for economic traits are assessed. A model was developed to measure the flow of superior Large White and Landrace genes identified in the test to the pig population by identifying the influential Breeder herds and examining the boar testing and replacement policies in these herds. A number of inefficiencies in the flow of genes from the test was identified and their effects measured. The chief of these was the practice by Breeder herds of drawing only a small proportion of their sire replacements from the test and not including among them those boars which performed best. This practice was more marked in the Large White than the Landrace breed. Inefficiencies reduced by 89 per cent the possible contribution of the test to improvement in herds whose breeding stock descended from the Breeder herds. Ways in which central boar tests might be more efficiently used are discussed. The most promising for Queensland seems to be to restrict testing space to a nucleus of co-operating herds and to replace herd sires only with tested boars of highest score.