Breakthroughs in Equine Embryo Cryopreservation.

This research highlights the challenges and recent advancements in the freezing and preservation of horse embryos for transfer, with reported pregnancy rates of 50% to 70% using certain methods.

Background

• Historically, equine embryos have mostly been collected and immediately transferred from the donor mare, either fresh or cooled and shipped to a recipient station for transfer within a day. However, there are numerous advantages to embryo cryopreservation, i.e., freezing and storing them for later use.

Challenges

• This research tells of two primary stumbling blocks in the process of equine embryo cryopreservation.
• The first is that only the smaller embryos (those under 300 micrometers in size) yield satisfactory pregnancy rates following the freeze/thaw cycle and subsequent transfer.
• Secondly, finding a functional process for superovulating mares, that is, inducing them to release multiple eggs during each cycle, is proving difficult. Without such a process, there is a scarcity of surplus embryos available for freezing.

Current Findings and Methods

• Regardless of these obstacles, significant advancements have been made. Using either a ‘slow cool’ method or a vitrification method (a rapid cooling process), the researchers report an encouraging 50% – 70% range of success in terms of the resulting pregnancy rates of the smaller equine embryos post-freezing/thawing.
• These findings indicate that even though the cryopreservation process might not yet be suitable for all equine embryos, it does present a promising approach for the preservation and subsequent successful transfer of smaller embryos.

Significance of Study

• This study is significant as it presents potential solutions and advancements to the noted challenges in preserving and storing equine embryos. This could greatly benefit horse breeding and the equine industry by perhaps allowing for more flexible and efficient breeding schedules, reducing the risk of disease transmission, and even aiding in the conservation of valuable or endangered genetic lines.