In vitro maturation and transfer of equine oocytes after transport of ovaries at 12 or 22 degrees C.

This research study explores the viability of transporting equine ovaries for in vitro fertilisation. It compares the effectiveness of storing these ovaries at two different temperatures, 12 and 22 degrees Celsius, during transportation periods between 18 and 24 hours. The primary aim is to achieve successful pregnancies via the in vitro maturation and transfer of oocytes obtained from these transported ovaries.

Objective and Methodology

• The study aims to understand the viability of shipping equine ovaries — a critical aspect for equine breeding, research, and conservation purposes, specifically in cases involving the demise of a valuable mare.
• Part of the procedure involves subjecting the transported ovaries to in vitro maturation, followed by oocyte transfer to generate successful pregnancies.
• To realise these objectives, ovaries from 4–7 mares procured from an abattoir were packed at two different temperatures: around 12 degrees Celsius and 22 degrees Celsius.
• Upon receipt in the laboratory, oocytes harvested from these ovaries were cultured for 24 hours.

In Vitro Fertilisation

• For each transfer, 9–15 oocytes were placed into the oviducts of mares in estrus — a process executed through standing flank laparotomies.
• To ensure synchronised ovulation, the recipient mares were administered human chorionic gonadotropin (hCG; 2000 IU, i.v.) 30–36 hours before the transfer.
• Further, 18–20 hours before the transfers, the mares were inseminated with 2 x 10(9) progressively motile sperm.

Assessment and Results

• Post-transfer, the uteri of the recipient mares were examined using ultrasound to ascertain the number of developing embryos. On Day 16, embryonic vesicles were recovered.
• A Chi-square analysis revealed no significant difference in the percentage of oocytes developing into embryonic vesicles between the two transport temperatures.
• In conclusion, successful pregnancies were achieved from the in vitro maturation of oocytes drawn from ovaries shipped for 18–24 hours at both 12 degrees and 22 degrees Celsius.