Health Traits and Work with the NZ Dairy Sheep Industry

Genetic and infectious diseases are of major importance to livestock production worldwide. There is well-documented evidence for between-animal variation in the ability of sheep to resist multiple infectious diseases of economic importance, including both pneumonia and facial eczema. These heritable differences mean that improvement of animal health through genetic selection for enhanced resistance can be used as a complementary approach to current methods for disease control. Genomics can also be used to further increase our understanding of disease, be it differences in the ability to withstand infection, or causative mutations for inherited disease. Multiple genomic tools are available to pinpoint the small genetic differences that produce a variety of traits in livestock, including SNP chips and whole-genome sequencing. Large phenotypic datasets have been used in conjunction with high and low density genotyping to interrogate the sheep genome for regions associated with variability in resistance or tolerance to pneumonia and facial eczema, respectively. In an alternative approach, whole genome-sequencing has been used to search for a causative mutation for Cerebellar Cortical Abiotrophy (CCA), a genetic neurological disease in Wiltshire sheep.