Genetic Selection, to Improve Natural Resistance to Disease
Concerning animal welfare
Resistance to disease, or more generally the ability of animals not to become ill, represents a major objective health-wise and concerning animal welfare. For example, a natural resistance to mastitis offers the double advantage of limiting the use of drugs and providing obvious comfort for the animal.
There are natural genetic differences between animals for resistance to specific diseases or for tolerance of infections. In cattle these genetic differences have been observed for resistance to diseases such as foot and mouth disease, leukaemia, mastitis and tuberculosis.
With enough information it is possible to put in place control or selection programmes based on disease resistance. Knowledge of the status of animals, whether carriers or not, is the basis of a programme for managing an anomaly, either for its control over time by avoiding at-risk matings, or complete eradication by routinely avoiding the selection of carrier animals. However, selection will probably never be the only tool used to fight these diseases. In fact, it must be incorporated into existing tools such as prevention, veterinary interventions and nutrition.
Genomics has made the search for gene causes of anomalies easier by using QTL detection methods. High speed genotyping chips offer new possibilities for locating the genes in question.