Genome-wide association study for heat stress resistance in Brown Swiss cattle in Yucatan, Mexico

Global climate change has made heat stress tolerance an important trait to be considered in breeding programs to improve the resistance of produc-tive animals to unfavorable environmental conditions. The aim of this study was to know the association between single nucleotide polymorphism (SNP) markers and heat stress resistance through a genome-wide association study (GWAS). Where 95 Brown Swiss dairy cows have measured body tempera-tures, respiratory frequencies, and genotypes. Seven SNP were detected with a statistically significant effect (P < 0.01) on respiratory frequency under heat stress. The markers with the highest association are in the Bos taurus autosome 6 (BTA 6), e.g. the BovineHD0600010397 SNP located within the FAM13A gene, and the BovineHD0600012612 SNP located within the PI4K2B gene. The ARS-BFGL-NGS-102407 SNP that is located in BTA 4 is the SNP that presents the highest number of associations to genes. Most of the genes are involved in cellular processes that are present in the resistance of individuals to high and humid environmental temperatures. These results provide new insights into the genetics of heat stress tolerance in Brown Swiss cattle in Yucatan, Mexico.