Pregnancies attained after collection and transfer of oocytes from ovaries of five euthanatized mares.

This research article investigates the possibility of collecting viable oocytes from the ovaries of deceased mares, then transferring and fertilizing them in recipient mares to produce healthy foals.

Research Objectives

• The main objective of the study was to verify whether the collection, cultivation, and transfer of oocytes harvested from ovaries of euthanized mares could successfully result in pregnancies.
• The authors also aimed to provide practical guidance for the process, such as how to preserve and transport the ovaries from deceased mares to a laboratory in order to maintain viability of the oocytes.

Methods and Findings

• Ovaries were harvested from five euthanized mares and sent to a laboratory, in which a total of 46 oocytes were collected.
• The collected oocytes were cultured for a period of 24 to 30 hours. After this period, 36 viable oocytes were identified and subsequently transferred into 10 recipient mares through a surgical procedure called a flank laparotomy.
• The recipient mares were then inseminated with semen from various stallions in an attempt to fertilize the transferred oocytes.
• Approximately 16 days after the oocyte transfer procedure, it was found that four of the recipient mares were pregnant, with at least one embryonic vesicle (early stage embryo) detected in each mare.
• However, out of these initial pregnancies, embryonic death occurred in three of the recipient mares. Despite this, one of the pregnancies resulted in the birth of a healthy foal.

Implications

• The study concludes that oocytes from euthanized mares can indeed be viable and could potentially lead to a successful pregnancy if transferred to a living recipient mare.
• The authors suggest that careful handling and transportation of the ovaries post-euthanasia are crucial factors in maintaining the viability of the collected oocytes. For instance, the researchers note that temperature fluctuations should be minimized and chilling of the ovaries should be avoided whenever possible.
• This work opens up potential new avenues for equine reproduction, especially for valuable mares that may die unexpectedly or have to be euthanized due to health problems.