Joint Analysis of the DGAT1, OPN and PPARGC1A Genes Effects on Variation of Milk Production and Composition in Holstein Cattle Population

The aim of this study was to investigate effects of DGAT1, OPN and PPARGC1A candidate genes on milk production traits in Iranian Holstein cattle. Several papers have studied single nucleotide polymorphisms (SNPs) and their association with economic traits in dairy cows, but the combined effect of these genes has not been examined in Iranian Holstein cattle population. Blood samples were collected from 398 registered Holstein cows. Total DNA was extracted using the salting out protocol. The PCRRFLP technique was used for SNPs genotyping. The largest genotype frequency was estimated as 0.65 for PPARGC1A (c.1892)^CT and the least frequency was estimated as 0.09 for DGAT1^KK genotype. The allele frequencies were in the range 0.36 to 0.64 for PPARGC1A (c.3359)A and Calleles,respectively. The allelic substitution effects were estimated using a multiple regression model. The effects of allelic substitution for DGAT1^K and PPARGC1A (c.1892)^T were significant on estimated breeding values for fat percentage (EBVFP) (P lt;0.01). In addition, the results of multivariate analysis indicated the significant effect of DGAT1 and PPARGC1A (c.1892) on EBVFP (P lt;0.05). However, there were no association between OPN and PPARGC1A (c.3359) polymorphisms and studied traits.