Association of GH|MspI and GHRH|HaeIII Genes with Milk Components of HF Dairy Cows under an Intensive Management in West Java

Abstract

Growth hormone (GH) and Growth Hormone Releasing Hormone (GHRH) genes control on growth tissues and lactation trait in dairy cattle. This study was aimed to evaluate genetic polymorphism and association of Growth Hormone (GH|MspI) and Growth Hormone Releasing Hormone (GHRH|HaeIII) genes to daily milk components of HF cows maintained intensively at a dairy cattle station in Lembang District, West Java. Genotyping of the two genes were done for 55 HF lactating cows using PCR-RFLP method.  Association of variant genotypes to each daily milk component (milk, fat, SNF, Protein and DM) were analyzed by GLM considering lactation length (months), lactation period and the two growth genes as the fixed factors. Genotyping the GH|MspI gene resulted C allele (0.4052) and T allele (0.5948); while for GHRH|HaeIII gene produced A allele (0.2931) and B allele (0.7069).  The GH|MspI gene affected significantly on protein and SNF (P<0.05), whilst the GHRH|HaeIII gene had no significant effect (P>0.05) on milk components. HF cows with CC and CT genotypes of the GH|MspI gene produced milk (11.03, 10.15 lt.), fat (3.24, 3.21%), SNF (8.31, 8.27%), protein (3.11, 3.12%), and DM (11.55, 11.47%).  Those cows with AA, AB and BB genotypes of the GHRH|HaeIII gene produced milk (9.00, 10.06, 11.14 lt.), fat (3.41, 3.23, 3.19%), SNF (8.18, 8.30, 8.29%), protein (3.07, 3.10, 3.13%), and DM (11.58, 11.51, 11.48%). It was concluded a fairly good control of the GH|MspI to SNF and protein contents in HF cows.