Abstract
This study was aimed to evaluate the relationship between growth hormone (GH) gene polymorphism and milk production in Najdi sheep. Two hundred Najdi ewes were used to determine the daily milk yield (DMY). The complete CDS of the Najdi sheep GH gene is1950 in length, GenBank acc. no. KU310891.1. Najdi sheep GH protein consists of 217 amino acids GenBank ALT22407.1 with conversion amino acid arginine number 121 to amino acid lysine (R121K). A novel five SNPs were detected in Najdi sheep GH gene (G871A, A1259C, G1383A, A1486G and A1509G). A significant association between the detected SNPs genotypes and daily milk yield was found in this study. The regression analysis indicated the positive effect of genotype and SNPs on DMY. Individuals carrying homozygote mutant alleles had the highest DMY. Consequently, these SNP may be useful indicators in the selection of ewes for milk production.