Akademik Veri Yönetim Sistemi
ARCHIV FÜR TIERZUCHT, cilt.67, ss.455-467, 2024 (SCI-Expanded)
Research on the diacylglycerol acyltransferase 1 (DGAT1) K232A marker in cattle shows inconsistent
results across regions, largely due to small sample sizes, limited genetic variation, and data restricted to
few lactations, which complicates establishing a reliable genotype–phenotype correlation. This research aimed
to determine the effect of the K232A polymorphism of the bovine DGAT1 gene on milk production and quality
traits in dairy cattle. We used 1104 cattle, including 828 Holstein Friesian and 276 Jersey cows. The analysis
utilized extensive data from six lactations of cows raised on four commercial dairy farms. We genotyped the
population using the polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP) technique
and Sanger sequencing for verification. We then evaluated the 305 d and test-day milk yields as well as
fat and protein yields and percentages. The number of inseminations per conception and calving ease were also
assessed as reproduction indices. Genotype–phenotype associations were quantified using linear mixed models.
The AA genotype was absent in Jersey cows, and the heterozygous genotype was predominant in both breeds.
The K232A marker was significantly associated with test-day milk yield, fat, and protein content in Jersey cows.
Further, it substantially affected the fat percentage of milk in Holstein Friesian cows (p<0:001). We found that
the KK genotype is highly desirable for milk quality and especially fat content. This comprehensive assessment
demonstrated that the KK genotype of the DGAT1 K232A polymorphism significantly influenced fat and protein
contents in dairy cattle.