Effects of SNP within Exon 7 of the Insulin-like Growth Factor Receptor Type 1 (IGF1R) Gene on Growth Traits in Angus Cows

Insulin-like growth factor 1 receptor (IGF1R) signaling pathway plays a key role in the postnatal growth and development. The tyrosine kinase receptor IGF1R forms homodimers that is activated by IGF-I which trigger autophosphorylation of IGF1R and subsequent downstream signal transduction. The objectives of this study were to identify, characterize and the examination of the association between silent SNP (rs41961336; CaT) within exon 7 of bovine IGF1R gene and growth traits. A total of 672 cows of four breeds was genotyped using the Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) method. A TaiI restriction endonuclease was used. Among all breeds under study (Polish Holstein Friesian, Angus, Hereford, Limousine), the presence of all three genotypes was observed only for the Angus breed. The CC genotype was the most frequent in all investigated breeds (0.7987-0.9904) followed by CT (0.0096-0.1946). Only Angus cows were selected for association analysis. At weaning weight adjusted to 210 days of age (WWT210), statistically significant differences (P≤0.05) were shown female calves with the CC genotype were heavier (+5.5 kg) than the individuals with the CT genotype. However, individuals carrying the CT genotype had significantly higher body weight at first calving (+10.62 kg; P≤0.05). The present work failed to show association between genotypes of the IGF1R/TaiI polymorphism and BWT, ADG or age at first calving.