On-site oocyte collection
For on-site oocyte collection, mares are housed at the Equine Reproduction Laboratory. Generally, we can collect two types of oocytes from mares:
- Immature oocytes: Often collected from smaller follicles and must be artificially matured within an incubator.
- Mature oocytes: We can also collect an oocyte from a large follicle just prior to ovulation. In this case, the oocyte has begun to mature and prepare for fertilization naturally within your mare’s follicle.
Each situation is different, and the decision to collect either is based upon consultation with one of our veterinarians. For either oocyte collection technique, an ultrasound probe positioned within the vagina of the sedated mare provides images of the ovarian follicles while properly positioning the ovary. For the oocyte collections, a needle is punctured through the vaginal wall and into individual follicles, and gentle suction applied to collect oocytes. The number of oocytes recovered varies per mare and aspiration attempt.
Following collection, oocyte(s) can undergo ICSI in our lab or be shipped to a lab of your designation (requires prior notification and desired shipping is via commercial airline).
Receiving off-site oocytes for ICSI
Both mature and immature oocytes can be collected through transvaginal aspiration procedures by a veterinarian located closer to your mare and shipped to the Equine Reproduction Laboratory for sperm injection (ICSI). Your attending veterinarian will package the collected oocytes in a special medium and arrange for transport to our facility.
- Immature oocytes are accepted Monday-Wednesday via FedEx or UPS flight-only shipping. Must be shipped within an appropriate shipping container that holds the temperature at ~22°C within appropriate media.
- Mature oocytes are accepted Monday-Wednesday via FedEx or UPS flight-only shipping. Must be shipped within a portable incubator that holds the temperature at ~38°C within appropriate media and arrive within 40 hours of an ovulation induction agent administration.
The veterinarian managing your mare should stay in contact with our front office staff to ensure proper timing, stallion/semen selection, handling and shipping of the oocytes.
Preparing for sperm injection
Once received, oocytes are cultured in an incubator until mature enough to undergo the sperm injection process (ICSI). This can take anywhere from 12-30 hours depending on oocyte maturity. Any embryos that develop after ICSI can be vitrified (frozen), transferred into an Equine Reproduction Laboratory-managed recipient mare, or shipped to another embryo transfer facility of your choice.
If you elect to have embryos transferred to another facility, we will need that information at the time the oocytes arrive to ensure we can communicate properly with the facility for recipient mare management.
Oocyte collection from deceased mares
Untimely death of a valuable broodmare is an unfortunate consequence of horse ownership. Gamete rescue, collection of the mare’s ovaries to obtain oocytes and propagate genetics, is a technology available at the Equine Reproduction Laboratory. We offer 24/7 support for referring veterinarians and mare owners interested in pursuing this procedure.
Our team will provide step-by-step instructions for extraction and packaging of ovaries for shipment to our facility. Because we close for seasonal vacations and holidays, please call our office prior to shipping ovaries to ensure we are available for the entire process. We view all postmortem shipped ovaries as an equine emergency and will initiate collection of oocytes as soon as ovaries arrive at our facility any time of day or night.
Following the harvest of oocytes, a procedure called intracytoplasmic sperm injection (ICSI) can be used to fertilize the oocytes and hopefully lead to the development of embryos. Semen must either arrive with or no later than 24 hours following arrival of your mare’s ovaries or oocytes.