Effect of altrenogest on pregnancy maintenance in unsynchronized equine embryo recipients.

This research explores the impact of altrenogest on maintaining pregnancy in unsynchronized equine embryo recipients. The study discovered that treatment with altrenogest could improve the likelihood of successful embryo transfers and the maintenance of pregnancies, especially in cases of luteal dysfunction.

Methodology

• Non-surgical removal of embryos was performed on mares of different reproductive histories on Day 7 following ovulation.
• The recovered embryos were then transferred non-surgically into recipient mares that were treated with altrenogest.
• The ovulation period of the recipient mares was either 3 days before or after the donor mares.

Results

• The embryo recovery rate among the donor mares was discovered to be 57%.
• When these embryos were transferred into altrenogest-treated recipient mares, a pregnancy rate of 77% was observed within the first 30 days.
• For recipients that ovulated between 4 days before and 6 days after the donor, the pregnancy rate dropped slightly to 64% at Day 30 of gestation.
• Those recipients that started treatment during oestrus or ovulated 5 or more days before the donor, did not maintain pregnancy.
• No significant difference was observed in the mean plasma progesterone concentrations of pregnant mares treated with altrenogest and those that weren’t treated.

Conclusion

• The researchers concluded that altrenogest treatment in embryo-recipient mares appeared beneficial in extending the degree of donor-recipient synchrony required for successful embryo transfer.
• Altrenogest treatment was also seen as potentially helpful for maintenance of pregnancy in embryo recipients experiencing luteal dysfunction.