Deep freezing of horse embryos.

The research conducted involves the process of deep freezing horse embryos and later transferring them to unmated mares to establish pregnancies. Although the study resulted in some initial conceptus establishment, only one mare maintained her pregnancy to term.

Methodology

• The study focused on a total of fourteen horse embryos, which were obtained non-surgically between the 6th and 8th days following ovulation. The day of ovulation was referred to as Day 0.
• These collected embryos were subjected to a slow cooling process, where they were cooled to – 35 degrees C for seven embryos and – 40 degrees C for the rest.
• Following the cooling process, the embryos were stored in liquid nitrogen at a temperature of – 196 degrees C. This storage duration varied between 4 to 98 days.

Transference and Results

• Surgical transfer of these thawed embryos was carried out into recipient mares that had ovulated – 2 to + 1 days with respect to the embryo donors.
• This process yielded in the establishment of 4 conceptuses initially. However, maintaining the pregnancy to term proved to be a challenge as only one mare could successfully do so.

Conclusions

• The study demonstrates that it is possible to deep freeze horse embryos and later transplant them into mares to trigger pregnancies. This process, if optimized and made more efficient, can be beneficial in horse breeding and preservation.
• However, the challenge lies in ensuring that the mares are able to maintain these pregnancies through to term. As the study showed, only one mare out of the ones that established conceptuses could do so.
• Future work needs to explore ways to solve this challenge, focusing on optimizing the processes before, during and after the transplantation to increase the likelihood of full-term pregnancies.