Effect of IGF-1 C472T, GH C2141G, and GHR T914A polymorphisms on growth performance and feed efficiency in young Kazakh white-headed cattle

BACKGROUND AND AIM: Improving the feed efficiency of beef cattle is necessary to increase the profitability of meat production. Implementing marker-assisted selection breeding systems can improve the genetic potential of beef cattle for increased productivity. This research aimed to study the effects of insulin-like growth factor (IGF)-1 C472T, growth hormone (GH) C2141G, and GH receptor (GHR) T914A polymorphisms on growth performance and feed efficiency in young Kazakh white-headed cattle. MATERIALS AND METHODS: Young Kazakh white-headed cattle (n = 50) were grouped after weaning according to sex (28 bulls and 22 heifers) and they were genotyped according to the IGF-1 C472T, GH C2141G, and GHR T914A polymorphisms. The test period was conducted from 8 to 15 months of age. The experimental animals were evaluated for live weight (LW) at the beginning and end of the test period. They were also assessed for average daily gain, hip height, metabolic mid-weight (MMWT), actual dry matter intake (DMI), and residual feed intake (RFI). RESULTS: Significant differences in MMWT were found between the bulls with the IGF-1(TT) and IGF-1(CT) genotypes, which was a 2.2 kg increase in heterozygous cattle (p < 0.05). Heterozygous IGF-1(CT) bulls differed with a higher DMI of 0.087 kg/day (p < 0.05) compared to IGF-1(TT) homozygotes. Carriers of the IGF-1(TT) genotype had the greatest feed efficiency at 0.068 kg/day (p < 0.05). Heifers with the GH(CC) genotype differed in their maximum DMI with an increase of 1.17%–1.57% (p < 0.05) relative to the other genotypes. The G allele in the GH C2141G polymorphism was associated with better (p < 0.05) feed efficiency in the Kazakh white-headed breed. The minimum DMI and RFI in GHR T914A heterozygous heifers were significantly inferior (p < 0.05) to the other genotypes. CONCLUSION: Association studies of the IGF-1 C472T, GH C2141G, and GHR T914A polymorphisms indicate a relationship between growth, development, and feed efficiency with the genetic characteristics of young Kazakh white-headed cattle. A significant (p < 0.05) dominant effect was found in the IGF-1 gene in bulls and in the GHR gene in heifers, which should be considered when breeding with heterogeneous parental pairs. The negative effect of the allele substitution in the IGF-1 C472T polymorphism was observed in the LW of heifers (−3.25 kg) at the age of 8 months and bulls (−6.05 kg) at 15 months. The substitution in the GH C2141G polymorphism was associated with a significant reduction in DMI by 0.036 kg (p < 0.05) and an increase in feed efficiency by 0.023 kg (p < 0.05) during the rearing of heifers. These results can improve the production efficiency of mature herds of Kazakh white-headed cattle.