Impact of donor mare and stallion identity on the likelihood of pregnancy after transfer of in vitro produced embryos

IVEP is a very efficient way to obtain pregnancies. The likelihood of pregnancy after transfer of an IVP embryo has improved over time, and individual mare and stallion identity seems to have a low impact. However, for some underperforming mares, results differ markedly depending on the stallion used for intracytoplasmic sperm injection.