Relationships Of Single Nucleotide Polymorphisms In GH And GHR To Growth Performance, Carcass Quality And Meat Quality Of Holstein Bulls

Single nucleotide polymorphisms (SNP) of Growth Hormone (GH) and GrowthHormone Receptor (GHR) genes were detected from39Holstein bulls. Bulls werefattened in a feedlot and body weight and measurements were made (body height,length, chest circumference, abdominal circumference, cannon circumference andbody weight) every30days. Relationships of growth and body characteristics weredone through statistical analyses. Thirteen Holstein bulls were selected to evaluaterelationships of GH and GHR SNPs to carcass quality at17or18months of age. Thus,the objective of the study was to determine if variation in GH and GHR genotypes ispotentially useful for marker assisted selection in improvement of feedlot growth andcarcass quality in Holstein bulls. The results were as followed:1. A polymorphism of GH was detected in the5th exon, caused by a missense C→Gtransition at2141bp position, leading to a valine substitution for leucine. The G allelewas positively associated with growth performance;2. A polymorphism of GHR in the8th exon was based on the missense mutation ofT→A in the4962bp position, leading to tyrosine substitution for phenylalanine. The Tallele was positively associated with growth performance;3. The24h carcass weight, the meat percentage and carcass meat percentage of the ATGHR genotype were higher than AA;4. The interaction of GH genotype aging days was evident for shear force (P<0.05)with genotypic differences decreasing with increasing aging days;5. The interaction of GHR genotype aging days was evident for cooking loss(P<0.05) with genotypic differences decreasing with increasing aging days;...