Autogenous transfer of intracytoplasmic sperm injection-produced equine embryos into the uterus of the oocyte donor during the same oestrous cycle.

This study discusses a novel approach in horse reproduction where oocyte donors can carry their own embryos produced via intracytoplasmic sperm injection (ICSI) during the same cycle, serving as both the donor and recipient. This can potentially reduce the associated costs of transferring these embryos into recipient mares.

Objectives and Methodologies

• The research aims to explore the possibilities of having fertile oocyte donors carry their own ICSI-produced embryos. This approach, if successful, can eliminate the need for recipient mares in such processes, hence minimizing the cost implications.
• The researchers experimented with mares in oestrus having large dominant follicles. These mares were administered with drugs that induce ovulation, stimulating the maturation of both follicle and oocyte.
• The matured oocytes were then collected, cultured, and fertilized under laboratory conditions using ICSI.
• Between six to seven days post-ICSI, the developed blastocysts were transferred back into the uteruses of the original oocyte donor mares. Subsequently, the researchers determined the pregnancy rates.

Findings and Conclusion

• From nine mares, 20 follicles were aspirated and 12 oocytes were collected. Out of the collected oocytes, 10 (83%) cleaved after ICSI.
• From the cleaved oocytes, eight (67%) developed into transferable blastocysts.
• Five pregnancies were successful from the eight transferred embryos, yielding a 62% pregnancy rate per embryo and a 42% pregnancy rate per sperm-injected oocyte.
• The study concludes that with a proper timing match, ICSI-produced embryos can be transferred back to the donors’ uteruses in the same cycle. This allows fertile oocyte donors to carry their own pregnancies after assisted fertilization, thus providing a more cost-effective approach in equine reproduction.