Polymorphisms within the <em>IGF1</em> and <em>IGF1R</em> genes associated with superovulation-related traits in Holstein dairy cows managed in a semiarid environment

Abstract

Embryo transfer (ET) is an artificial reproductive technology used for the genetic improvement of cattle. High variation has been observed in superovulation (SPO) and embryo flush recovery, which appear to be influenced by donor cow genetics. Then, the objective was to identify single nucleotide polymorphisms (SNPs) from the genes IGF1 and IGF1R associated with reproductive traits related to SPO response in dairy cows raised in a semiarid region. Sixty-four Holstein cows were subjected to SPO, artificial insemination, and nonsurgical embryo collection. Individual blood samples were collected and used to genotype 13 SNPs from the genes IGF1 and IGF1R. Additional blood samples were collected to measure anti-Mullerian hormone (AMH) concentrations. Ovarian and embryo traits related to SPO response were evaluated. A mixed-effects model was used to identify associations between SNPs and SPO-related traits. A regression model was implemented to calculate allele substitution effects. From 13 SNPs, the SNP rs109763947 in the gene IGF1 and the SNPs rs110343126 and rs208140993 in the gene IGF1R were predictors for six traits evaluated in superovulated cows. The most favorable genotypes for these SNPs were CC, AA and GG, respectively. A linear trend was detected, suggesting an additive effect of the genes. Moreover, all traits evaluated in the current study improved as the number of favorable SNP genotypes increased, confirming a positive contribution of the SNP genes. In conclusion, three SNPs in the genes IGF1 and IGF1R were marker predictors for reproductive traits related to SPO response and embryo production in Holstein cows managed in a semiarid region.