Association of DGAT1 and POU1F1 Gene Polymorphisms With the Milk Traits in the Cross-Bred Hamdani Sheep Bred Under Extensive Management.

Background: Milk production and composition are affected by genetic and environmental factors. Among key genetic regulators, the POU1F1 and DGAT1 genes play significant roles. POU1F1 affects pituitary gland functions and hormone secretion, indirectly impacting milk production. DGAT1 is crucial for milk fat synthesis. Understanding genetic variations in these genes can enhance breeding strategies for improved milk yield and quality.

Objective: This study investigates the relationship between POU1F1 and DGAT1 genes and milk composition in cross-bred Hamdani sheep.

Methods: Blood and milk samples from 70 sheep were analysed for genetic markers using PCR-RFLP technique. Statistical analysis assessed the relationship between genotypes and milk composition.

Results: Results showed that DGAT1 genotypes (CC and CT) were in Hardy-Weinberg Equilibrium (HWE), whereas POU1F1 genotypes were not. C and T allele frequencies were found 0.9 and 0.1 for DGAT1, respectively. On the other hand, the frequencies of C and T alleles were 0.52 and 0.48 for POU1F1, respectively. For DGAT1 gene, CT genotypes carrying ewes had higher milk fat compared to CC genotypes (p < 0.05). However, no differences were observed in milk solids-not-fat, protein and lactose content between genotypes (p > 0.05). Effect sizes were detected as 0.83 (large) for fat percentage comparison, 0.09 (small) for percentage of solids-not-fat and 0.06 (small) for percentage of protein and lactose. Association analysis did not perform for POU1F1 gene due to low sample size in CC genotype.

Conclusion: These findings suggest that DGAT1 variations may influence milk fat content, whereas POU1F1's role remains unclear due to limited genotype variation. Further research is needed to clarify genetic influences of DGAT1 and POU1F1 genes on sheep milk in cross-bred Hamdani sheep.