The sustainability, feasibility and desirability of breeding livestock fordisease resistance

Selective breeding for disease resistance utilises proven animal breeding m ethods to improve animal health, welfare and productivity. Unsurprisingly, it is receiving more and more attention from livestock breeders. However, t here are a number of largely theoretical arguments that have been raised as potential problems in selection for disease resistance. These can be class ified under sustainability, feasibility and desirability. This review consi ders each of these areas in turn. Several examples show that enhanced resis tance to disease is stable under natural selection and therefore deliberate selection for disease resistance should also be stable and sustainable. Th e feasibility of selective breeding depends in part upon the heritability o f the trait or traits used to measure disease resistance, as well as the am ount of variation among animals. The heritability of traits associated with resistance to many important diseases is often high and considerable varia tion among animals exists. Consequently, selective breeding for enhanced di sease resistance is certainly feasible. The desirability of breeding for di sease resistance depends upon whether there are trade-offs with other econo mically important traits. By and large these remain to be defined. However, even if unfavourable associations exist, breeders can create selection ind ices that include traits with unfavourable associations and maximise the de sired responses while attempting to minimise undesirable effects. In conclu sion, so long as one or more diseases exert a significant influence on live stock production, selective breeding will be a useful tool to assist in dis ease control.