The fibroblast growth factor 2 gene is associated with embryonic mortality in cattle

The objective of this study was to investigate the association of the fibroblast growth factor 2 (FGF2) gene with embryonic survival and fertilization rate in cattle. This gene was chosen because of its role in regulating trophectoderm expression of interferon-tau, the maternal pregnancy recognition factor in ruminants. To evaluate the effect of FGF2 on fertility traits, we produced in vitro-fertilized embryos from 281 Holstein cows and from 7 sires. A total of 4,542 in vitro fertilizations were performed, from which a total of 3,171 embryos were produced. Survival and fertilization rates were assessed at d 7 of embryonic development. Using the pooled DNA sequencing approach, we identified 2 SNP in FGF2, SNP11646 and SNP23. All sires and cows were genotyped for these SNP. For fertilization rate, no significant differences between genotypes were found for either SNP, whereas the effect on survival rate was significant for SNP11646. The survival rate of embryos produced from GG cows for this SNP was 37%, compared with 28 and 29% for embryos produced from AG and AA cows, respectively. Although the molecular mechanisms that cause embryonic mortality have not yet been identified, this study provides the first evidence of association between FGF2 and embryonic mortality in cattle. Thus, we propose that FGF2 can be used in animal breeding strategies to test for improved reproductive performance.