Effect of altrenogest on pregnancy maintenance in unsynchronized equine embryo recipients.
Non-surgical embryo recovery attempts were done on Day 7 after ovulation. Embryo recovery rate from mares of varied reproductive histories was 57% (38/67). Non-surgical transfer of these embryos into altrenogest-treated recipient mares that ovulated between 3 days before and 3 days after the donor resulted in a 30-day pregnancy rate of 77% (10/13). Transfer of embryos into altrenogest-treated recipients that ovulated between 4 days before and 6 days after the donor resulted in an overall pregnancy rate of 64% (16/25) at Day 30 of gestation. No recipients that were in oestrus at the start of treatment, nor recipients that ovulated 5 or more days before the donor, maintained pregnancy. Mean plasma progesterone concentrations of pregnant, altrenogest-treated, embryo-recipient mares; pregnant, altrenogest-treated, untransferred mares; and pregnant, untreated, untransferred mares were comparable (P greater than 0.05). Treatment of embryo-recipient mares with altrenogest appears to be beneficial in extending the degree of donor-recipient synchrony required for successful embryo transfer. Altrenogest treatment also seems to be conductive to pregnancy maintenance in recipients experiencing luteal dysfunction.
D000818:Animals; D004624:Embryo Transfer / Q000662:veterinary*; D004963:Estrenes / Q000494:pharmacology*; D005260:Female; D006736:Horses / Q000502:physiology*; D010060:Ovulation; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000187:drug effects*; D011374:Progesterone / Q000097:blood; D045167:Progesterone Congeners / Q000494:pharmacology*; D014204:Trenbolone Acetate / Q000031:analogs & derivatives / Q000494:pharmacology*
D004963:Estrenes; D045167:Progesterone Congeners; C023445:altrenogest; D011374:Progesterone; D014204:Trenbolone Acetate