Kibar, MustafaAytekin, Ibrahim2024-12-242024-12-2420230022-02991469-7629https://doi.org/10.1017/S0022029923000717https://hdl.handle.net/20.500.12604/6808This study aimed to investigate the effect of leptin gene polymorphism and some environmental factors on milk production traits. Blood samples from 212 Holstein Friesian dairy cattle reared on a private farm were used. The intron 2 region of the leptin gene was digested with Sau3A I restriction enzyme using the PCR-RFLP method. A and B alleles and AA, AB, and BB genotype frequencies for the Sau3A I polymorphism were determined as 0.8821 and 0.1179, and 0.764, 0.236 and 0.000, respectively. Chi-square analysis revealed that the leptin gene polymorphism followed the Hardy-Weinberg equilibrium, including the absence of animals with the BB genotype. The effect of leptin gene polymorphism on all milk production traits was insignificant. For milk production traits, direct heritability ( h(a)(2) ) varied between 0.03 +/- 0.283 (for the dry period) and 0.50 +/- 0.183 (for milk conductivity). Regarding the milking time (MT), the estimated breeding values (EBVs) of cattle with the AA genotype were higher than the AB genotype ( P < 0.05). As a result of this study, in the selection program, allele or genotype could not be suggested as a marker for milk yield characteristics except for the possible exception of milking time and its relationship to mastitis incidence.eninfo:eu-repo/semantics/closedAccessBreeding valueHolstein Friesianleptinmilk yieldselectionArticle904339342N/AWOS:001142830100001Q12-s2.0-851822113543818620410.1017/S0022029923000717