INHA A192G polymorphism and its association with dairy traits in Antioquia Holstein cattle

The objective of this research was determining the effect of the A192G polymorphism in some productive and reproductive traits in Antioquia Holstein cows. To achieve this, the technique PCR-RFLP was used to amplify a segment of 249 bp of the bovine inhibin alpha gene (INHA) which was digested with the restriction enzyme MspI. The effect of the INHA genotypes on the productive and reproductive traits was determinate by a Mixed Linear Model and Tukey Test was used to establish significant differences between means for the three genotypes. The effect of allelic substitution was studied through a linear regression model where the genotypes AA, AG and GG were transformed into a quantitative scale of 0, 1 and 2, respectively according to the number of possessed G alleles. In Antioquia Holstein cattle the most common genotype was the AG (0.529) followed by AA (0.269) and GG (0.201) genotypes. Allele frequencies were 0.534 for A and 0.466 for G. The INHA genotypes did not exert a significant effect on the principal productive parameters, except for fat percentage where GG animals presented the highest value for this trait. Despite it was not a significant effect of this polymorphism on reproductive parameters, Tukey test showed that G allele tend to have a detrimental effect on female fertility, increasing the calving interval and the number of services per conception, decreasing the reproductive efficiency of the herds. Further studies are required to determine whether this SNP may be used as a molecular marker.