Association of single nucleotide polymorphism of Hsp90ab1 gene with thermotolerance and milk yield in Sahiwal cows

Heat shock proteins play a critical role in the development of thermotolerance and protection from cellular damage associated with heat stresses. The study was undertaken to investigate the association of single nucleotide polymorphisms (SNPs) of Hsp90ab1 gene with thermo-physiological parameters viz, respiration rate (RR), rectal temperature (RT), heat tolerance coefficient (HTC) and total milk yield in Sahiwal cows. The RR and RT were recorded once in different seasons, viz., winter, spring, and summer, at the probable extreme hot hours of the day. Polymorphism of Hsp90ab1 gene, evaluated by comparative sequencing revealed five SNPs, viz., T17871421C, C17871485del, C17872061T, T17872112C and T17872148G. Individuals with CT genotype recorded significantly (P≤0.01) lower RT (°C) than CC genotype in Sahiwal cows. The CT genotype animals also had better production parameter in terms of total milk yield (TMY) (P<0.01). Therefore, our results inferred that CT genotype in Sahiwal cows may be an aid to selection and breeding to enhance thermo-tolerance.   Key words: Hsp90ab1, SNPs, respiration rate, rectal temperature, total milk yield, Sahiwal.