INSIGHT IN LEPTIN GENE POLYMORPHISM AND IMPACT ON MILK TRAITS IN AUTOCHTONOUS BUSHA CATTLE

Leptin, a biomolecule secreted by adipose tissue, enchances productivity in cattle, especially affecting milk traits. The aim of this study was to detect leptin gene polymorphism on exon 3 (A59V locus) and intron 2 (SAU3AI locus) in the endangered population of autochtonous Busha cattle and associations with milk traits. The study included 46 cows: 36 Busha and 10 half-bred. Milk analyses comprised determination of somatic cell counts, fat, protein, lactose, total solids and solids-not-fat (SNF) concentrations and freezing point depression (FPD). Polymorphisms were determined by PCR-RFLP technique. A single A59V genotype (CC) was affirmed, and two SAU3AI genotypes, AA and AB, with frequencies of 78.26% and 21.74%, respectively. Comparing the obtained results for chemical characteristics of milk between cows with AA and AB, no significant differences were found, except for SNF content and FPD values. Cows with AA genotype had significantly lower (p = 0.021) average SNF content (8.74%) in milk compared to the average SNF content (9.28%) in those with genotype AB, while cows with genotype AA (-0.54 degrees C) had significantly higher (p = 0.004) average FPD values than those with AB genotype (-0.58 degrees C). The absence of BB genotype and significant differences in the investigated functional traits between two SAU3AI genotypes and the absence of A59V polymorphism (presence of only CC genotype) show that the Busha cattle breed, although being an autochtonous low-producing native breed used for meat and milk production, harbours polymorphism on gentic markers characteristic of high production dairy cows.