Genetic variability in exon 5 region of GH1 gene and its effect on milk production and milk composition traits in Karan Fries cattle

The study was conducted to identify the genetic variability in exon 5 region of GH1 gene and quantify its effect on production performance in Karan Fries cattle. PCR-RFLP method using Alu I restriction endonuclease was used for identification of genotypes. LL and LVgenotypes with frequencies as 0.46 and 0.54 and the frequency of L allele as 0.73 were found. Season of calving was only found significant (p ≤0.05) for fat yield of TD3, TD6 and TD10. The effect of SNP of GH1 gene (exon 5) increased the overall test day milk yield, fat yield and SNF yield by 1.05 kg, 43.2 gm and 103 gm. High correlations were obtained from TD3 onwards between test day traits and lactation milk yield indicating that selection based on identified SNP in TD3 increased test day milk yield, fat yield and SNF yield by 2.5229 kg, 62.9 gm and 215.9 gm, respectively.