Association of the Leu127 variant of the bovine growth hormone (bGH) gene with increased yield of milk, fat, and protein in Australian Holstein-Friesians

Abstract

The occurrence of the Leu127/Val127 variants of the bovine growth hormone (bGH) gene and their effect on milk production traits was investigated in Australian Holstein-Friesian cattle. Animals were genotyped for the Leu127/Val127 variants, with RFLP methodology, using PCR and AluI digestion of PCR products (AluI-RFLP). Alleles Leu127 and Val127 occurred with frequencies of 82% and 18%, respectively. The quantitative effect of this polymorphic site on milk-production traits was estimated from lactation data and test-day data. Results from the 2 data sets consistently showed that the Leu127 allele is associated with higher production of milk, fat, and protein and is dominant to Val127. The average effects of the gene substitution are 95 L for milk yield, 7 kg for fat yield, and 3 kg for protein yield per lactation. This locus may be directly responsible for quantitative variation or it may be a marker for a closely linked quantitative trait locus (QTL) for milk-production traits in Australian dairy cattle. In either case, it will be useful as an aid to selection for improvement of milk production traits. As the Leu127 allele is dominant, selection of AI sires homozygous for the Leu127 allele (Leu127/Leu127) will result in maximum benefit without the need for genotyping cows.

Interrelationship of growth hormone AluI polymorphism and hyperketonemia with plasma hormones and metabolites in the beginning of lactation in dairy cows

“…We found allele frequencies of p L =0.850-0.920 for leucine and q V =0.080-0.150 for valine, which are in agreement with those previously reported in the Holstein-Friesian breed (Lucy et al, 1993;Shariflou et al, 2000;Kovács et al, 2006).…”

“…A polymorphic site of the GH gene (AluI polymorphism) that results in an amino acid change at position 127 of the protein chain (leucine, L to valine, V; Lucy et al, 1991) has been linked to milk production traits with various outcomes. Some authors favored the leucine (Shariflou et al, 2000;Dybus, 2002) or the valine allele (Grochowska et al, 2001;Zwierzchowski et al, 2002;Kovács et al, 2006), while Yao et al (1996) and Lechniak et al (2002) were not able to prove any association. Endocrine characteristics of the different genotypes have also been investigated and yielded contradictory results.…”

Determination of allele frequencies of growth hormone AluI polymorphism in Brown Swiss, Holstein, native East Anatolian Red and Turkish Grey breeds

“…These differences could be because of sample size and sampling error. Inter-and intrabreed variations with those previously reported in other taurine breeds were found to be an agreement in frequencies of growth hormone polymorphic variants (Lucy et al 1993;Grochowska et al 1999;Shariflou et al 2000;Kovacs et al 2006).…”

Influence of Csn3, Lgb, Prl, Gh, Tg5 Genes Alleles on Dairy Productivity and Energy Value of Cow's Milk

“…Sabour and Lin (Sabour & Lin, 1996), in turn, found that the V allele of the GH gene was preferable in terms of increasing the milk yield obtained from cows. On the contrary, Shariflou with coauthors (Shariflou et al, 2000) showed greater contribution of L allele to increase of milk yield in cows. Lucy with coauthors (Lucy et al, 1993) came to the same opinion in relation to the milk productivity of Holstein in USA, while the influence of the V allele was most pronounced in the Jersey cattle breed.…”