Identification of single nucleotide polymorphisms associated with mastitis resistance in dairy cows

Mastitis is the single most costly disease of dairy cattle, causing reduction of milk production, milk wastage, extensive use of antibiotics and loss of animals. Selective breeding for animals that are genetically resistant to mastitis has the potential to decrease the incidence of this disease in dairy cows. Identification of genetic markers associated with susceptibility to the disease should help to better guide these breeding programs. The purpose of this study is to identify genetic markers in the form of single nucleotide polymorphisms (SNPs) for mastitis resistance in dairy cows. We have carried out a rigorous mastitis screening program over an eight month period in a commercial dairy herd and have identified two groups of dairy cows, one mastitis resistant and the other mastitis susceptible. Genomic DNA has been isolated from each cow from these two groups and is being subjected to genome-wide genotyping array analysis using the Illumina BovineHD BeadChip. This array encompasses 770,000 SNPs that uniformly span the entire bovine genome, allowing genome-wide identification of genetic markers associated with a particular animal trait. We hypothesize that SNPs associated with mastitis resistance will be identified by this study and that these SNPs can be used as predictors of mastitis resistance