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  • Küçük Resim
    Öğe
    Associations between leptin gene polymorphism and some reproductive traits in Holstein-Friesian dairy cattle
    (Journal of the Hellenic Veterinary Medical Society, 2024) Mustafa Kibar; Aytekin İ.
    The aim of this study was to determine the effect of leptin gene polymorphism and other environmental factors on age at first breeding (AFB; day), age at first calving (AFC; day), service period (SP; day), number of inseminations per conception (NIPC; count), gestation period (GP; day) and calving interval (CI; day). For this purpose, whole blood samples were obtained from the Vena coccygea of 212 Holstein-Friesian dairy cattle reared on a private farm in Türkiye. The Sau3AI restriction enzyme with the PCR-RFLP method was used to determine the polymorphism of 422 base pairs (bp) in the intron 2 region of the leptin gene. The frequencies of the A and B alleles and the AA, AB and BB genotypes were determined to be 0.8821 and 0.1179, and 0.764, 0.236 and 0.000, respectively. There were no animals with the BB genotype in the population. The population of Holstein-Friesian was also at the level of Hardy-Weinberg equilibrium with regard to the leptin gene (P>0.05). The study found the highest direct heritability in the GP trait (0.33±0.268), while the lowest was observed in the NIPC trait (0.01±0.118). For the traits SP (P<0.10), NIPC (P<0.05), and CI (P<0.05), higher values were recorded in cattle with genotype AA compared to those with genotype AB. However, no significant association was found between genotypes and AFB, AFC, GP, and estimated breeding values (EBVs). This suggests that the heritability of these traits may not be strongly affected by the genotypes emphasized. As a result, the AB genotype or B allele could be used in selection for SP, NIPC, and CI, but the allele or genotype did not suggest marker-assisted selection (MAS) for AFB, AFC, and GP. Copyright
  • Küçük Resim
    Öğe
    Strong associations between the FGF-2 gene and productivity traits of Holstein-Friesian dairy cattle
    (Elsevier BV, 2025-03) Mustafa Kibar; İbrahim Aytekin
    Sustainability in dairy cattle farms depends on the efficiency of milk yield and reproductive traits. Thus, this study aimed to investigate the effect of the FGF-2/Csp6I gene and major environmental factors on these traits in Holstein-Friesian cattle. A total of 212 whole blood samples were collected from the Vena coccygea of cattle and the data obtained from these samples were used in all statistical analyses. Then, the restriction fragment length polymorphism (RFLP) method (determination of genotypes) was conducted and programs including PopGene (allele and genotype frequencies), Minitab (association analyses) and MTDFREML (variance components and genetic parameters) were used. Alleles A (0.4269) and G (0.5731) as well as genotypes AA (0.174), AG (0.505) and GG (0.321) were found, indicating that the population is polymorphic and in Hardy-Weinberg equilibrium (P > 0.05). The effect of the Csp6I polymorphism of FGF-2 gene on peak milk yield (PMY) (P < 0.01); lactation milk yield (LMY), milking time (MT), 305-day and 200-day lactation milk yield (LMY305 and LMY200), average daily milk yield (ADMY) (P < 0.05); 100-day lactation milk yield (LMY100), age of using in first breeding (AUFB) and number of inseminations per conception (NIPC) (P < 0.10) were significant. The heritability of milk yield traits and the correlation between direct and maternal heritability for reproductive traits were high. Furthermore, the breeding value of PMY was higher for the AA genotype (0.745 ± 0.292) than for the AG genotype (−0.268 ± 0.171) (P < 0.05). As a result, the A allele and AA genotype for the FGF-2/Csp6I gene had an increasing effect on milk yield without compromising reproductive performance in Holstein-Friesian dairy cattle.