the effect of osteopontingene polymorphism on milk production traits in brown swiss cattle

osteopontin gene is located at the end of chromosome 6 in cattle and it is one of the most important genes influence on milk protein percentage and reproduction. in this study, blood samples were collected from100 brown swiss cows and dna was extracted from whole blood by modified salting out procedure. cows were genotyped for single nucleotide polymorphism of intron iv by pcr-rflp and bsri restriction enzyme method. breeding values were individually predicted for milk production, fat and protein milk percent traits by restricted maximum likelihood method. association between polymorphisms and breeding values were calculatedat a 5% significant level. frequencies of tt, tc and cc genotypes were 0.32, 0.46 and 0.22, respectively. studied population was inaccord with hardy-weinberg expectation. there was no significant association between genotypes and breeding values of milk production, fat or protein percent traits.