A novel method for equine embryo transfer from contaminated recipient mares into second healthy recipients for surviving embryos.

The research presents a new technique to enhance the success rate of embryo transfer (ET) in horses by relocating the embryos from infected recipient mares to second healthier recipient mares. This study proved that such an approach protects the transferred embryo from inflammation and raises the overall chances of a successful pregnancy.

Objective and Methodology

• The purpose of this research was to find ways of maximizing the result of embryo transfer in horses. This was accomplished by re-flushing and re-transferring of embryos from recipient mares with signs of infection to healthier ones.
• Twenty-five recipient mares demonstrating embryonic vesicles in intraluminal fluid were used in the study. These mares were identified through ultrasound scanning 2 to 2.5 days after embryo transfer.
• The study was divided into two groups – a control group that consisted of seven mares that received no additional treatment, and a treated group of 18 recipient mares that underwent re-flushing and re-transferring of embryos to a second set of healthy mares.
• The fluid obtained from the treated mares was subject to cytological and microbiological examinations.

Research Findings

• The study found that the initial recipient mares had endometritis, identified by the presence of mixed and single infections, as well as polymorphonuclear neutrophils (PMNs).
• In the control mares, embryonic death was observed at around 14 days of embryonic age.
• The analysis of retrieved embryos from the treated group revealed that 66.7% had well-developed thick capsules while the remainder had normal capsules. The rate of embryo survival was significantly higher in embryos displaying the former characteristic.

Implications of the Study

• The study underscores the importance of inspecting the uterus of recipient mares during estrus prior to performing embryo transfer, and to follow up two days after the procedure.
• This new method can significantly increase the success rate of equine embryo transfer programs by safeguarding the transferred embryos from potentially harmful inflammatory processes, thus increasing chances of their survival.