Champion Mare's Legacy Lives on with Unusual Birth of Filly

After the mare died at the Cornell Hospital for Animals, veterinarian Sylvia Bedford-Guaus and her laboratory team ” graduate student Lori McPartlin and technician Stephanie Twomey ” made use of special tools and their expertise from years of research to scrape the wall of each follicle in both of the ovaries obtained from the mare, Rebaqua.

“The process is time-sensitive and very intricate,” said Bedford-Guaus, explaining that the eggs (oocytes) can only be seen microscopically and must be collected from the ovary within a few hours.

“There were other approaches, such as shipping the entire ovary, but none that could offer the success rates we had with this procedure,” she said, adding that when equine ovaries have been shipped before, few pregnancies have resulted in no live births because the oocytes do not stay viable within the ovaries.

Bedford-Guaus searched for oocytes under a dissecting microscope and washed them in a special medium. The process took more than three hours. “Racing against the clock,” said Bedford-Guaus, the team packaged nine oocytes for overnight shipment to veterinarian Katrin Hinrichs Equine Embryo Laboratory at Texas A&M University, where the researchers had the expertise needed to fertilize the eggs.

In Texas, the oocytes were incubated in a medium that stimulated five of the oocytes to mature; they were then fertilized with frozen-thawed sperm from the third-ranked barrel-racing stallion in the nation, Frenchmans Guy. This procedure, performed by veterinarian Young-Ho Choi, used a micromanipulation technique termed intracytoplasmic sperm injection. The fertilized eggs were cultured for seven days. Two developed into embryos, which were then sent to veterinarian David Hartman at the Hartman Equine Reproduction Center in Whitesboro, Texas, who transferred them to a surrogate mare that was at the right stage of the cycle to carry a pregnancy. The mare was then purchased by Rebaqua's owner, Kristin Contro of Binghamton, who had the pregnant mare shipped to New York.

“Because there are so many horses in the world, prior to Rebaqua's never felt it was necessary to breed a horse,” said Contro, who began riding when she was 10 and has owned more than 10 horses. “Rebaqua was as close to perfect as you could get. She was bred really well, so her genes were superb. Her confirmation was perfect. And, she was a champion barrel racer. I am hopeful that her foal will also have her heart. That's not something you can breed for. They either have it or they don't.”

(Text by Stephanie Specchio of Cornell's College of Veterinary Medicine.)