A new hormonal protocol supports early development of in vitro-produced embryos after transfer to anoestrus mares.

This research focuses on the effectiveness of a new hormonal protocol in aiding early development of in vitro-produced embryos, particularly after transferring them to non-cycling (anoestrus) female horses (mares).

Objective of the Study

• The main aim of this research was to determine whether non-cycling (anoestrus) mares can make suitable recipients for embryos generated via intracytoplasmic sperm injection (ICSI), a common technique in assisted reproductive technologies.

Methodology

• To carry out the experiment, the researchers confirmed anoestrus in four mares.
• These mares were then subjected to daily doses of a hormone known as oestradiol benzoate (6 mg in total) over a span of 5 days.
• After giving the mares a rest for 3 days, they were then orally administered another hormone, altrenogest, at a dose of 0.088 mg/kg.
• Subsequently, the embryos (ranging between 1 to 5 embryos per mare, with a total of 15 embryos) were transferred into the mares 3.5 days after the onset of progesterone, another hormone related to pregnancy.
• Finally, uterine lavage or a method of cleaning out the uterine cavity was performed 48 hours after the transfer of embryos.

Results

• The results of the study revealed an impressive 80% recovery rate of the embryos.
• Notably, among the embryos that were successfully retrieved, 67% showed evidence of intrauterine development, which indicates that the embryos were growing within the uterus.
• Therefore, the results imply that embryos created through ICSI can successfully be transferred to non-cycling mares that are pre-treated with a specific hormone protocol.

Conclusions and Further Work

• Despite the encouraging results, the researchers advocate for more studies in this area.
• This is crucial to ensure the further development of the embryo and successful full-term pregnancies, which in this experiment, were not confirmed.