HSP90AA1 Gene Polymorphism and its Relationship with Reproductive and Productive Traits in Holstein Cattle

The HSP90AA1 gene, as a member of heat shock protein family has a crucial role in cellular stress responses, particularly in thermotolerance and cattle fertility. Our study aims to determine the HSP90AA1 gene polymorphism and its relationship with cattle fertility and production. A total number of 305 cows were categorized into 3 groups (cyclic, post-partum anestrum (PPA) from 6 to 12 months, and PPA>12 months). Data on reproduction and production were gathered from farm records, including age at first calving, calving intervals, calf birth weights, milk yields, and milking days. Genomic DNA extraction and PCR-SSCP were conducted to detect three fragments of HSP 90AA1 gene F1, F2, and F3 at 285, 355, and 280 bp, respectively. Three different patterns were observed in HSP90AA1 F1, and F3. HSP90AA1 F2 was monomorphic. Sequence analysis of HSP90AA1 F1 showed 3 different genotypes (CC, AA, and AC) with single nucleotide polymorphisms (SNPs) (A/C) as a transverse single base substitution mutation located at 21:66942714 with ID rs207763220 as a synonymous mutation. While HSP90AA1 F3 revealed 3 genotypes (TT, GG, and TG) with only one missense SNP located at 21: 66941688 (T/A/G) with ID rs210718366. In the HSP90AA1 F1 gene, the CC genotype was linked to the lower calving interval and milk yield in cows with a PPA >12. In the HSP90AA1 F3 gene, the GG genotype was related to lower days of milking and milk yield. Additionally, the TT genotype was correlated with lower age at first calving in the PPA > 12. Our findings suggest that genetic variations in the HSP90AA1 gene may be used as a molecular marker for genetic selection to enhance reproductive and productive performance in Holstein cows, especially age at first calving, calving interval, and milk yield associated with post-partum anestrum.