Genome-wide Association Study of Resistance to Mastitis in Czech Holstein Cattle

Clinical mastitis is an inflammatory disease of the mammary gland that largely impacts dairy farming profitability and welfare. Globally, a massive scientific effort is being made to elucidate the possible link of certain genotypes to the susceptibility to this disease. After data pruning controlling for genotype missingness, minor allele frequency, and population stratification, 51 557 SNPs from 1 042 animals have been analysed using the general linear model (GLM). Two SNPs, BTA-121769-no-rs and BTB-00265951, have demonstrated statistically significant associations (-log 10 ( p ) >6.0134), both located on the chromosome BTA6. The detected SNPs have been annotated within a reference genome. They have been found to lie outside of transcribed regions but within the vicinity of genes essential for the immune response. This finding further supports the case for their significance in the resistance to mastitis. In addition, 14 relatively weaker associations (-log 10 ( p ) >4) have been observed across chromosomes BTA1, 2, 9, 14, 19, 24 and 25.