The process of breeding sport horses is ever-changing. Whether in an effort to produce the healthiest, most talented foals, to prolong the competition career of a mare, or make the most of a stallion’s longevity, reproductive science in horses has come a long way from the days of the traditional breeding shed.
Dr. Katie Atwood is a member of the Palm Beach Equine Clinic (PBEC) team, based in Wellington, FL, with a passion for reproductive work. She has used that passion to help PBEC offer cutting edge breeding options all in the heart of the winter equestrian capital of the world.
“I like the creating of life,” said Dr. Atwood, who is a Florida native and University of Florida graduate and currently pursuing steps to become a board-certified reproductive specialist. “Equine medicine is intriguing, but you’re dealing with sick, unhealthy animals. With reproduction, I am working with healthy animals and making their babies, which I love!”
The Future of Breeding at Palm Beach Equine Clinic
PBEC is a one-stop shop for anyone’s breeding needs, whether it’s a champion polo pony, competing mare, or full-time breeding stallion. Atwood and the team at PBEC work tirelessly to improve their offerings, which currently include a breeding shed covered from the heat and inclement weather just like an indoor arena. Inside the breeding shed, PBEC houses a hydraulic phantom mare.
“We can raise a lower our phantom with the push of a button so it can be the appropriate for the stallion,” said Dr. Atwood. “Previously, we had to bring a tractor in to raise and lower the phantom. We also do not have to take weather into consideration anymore now that the breeding shed is covered. There is enough space and privacy for safe and convenient breeding on-site at PBEC.”
Additionally, PBEC incorporates the use of a SCA® CASA (computer assisted sperm analyzer) system into their reproduction work. An excellent way to improve quality control of a stallion’s sperm, the system evaluates sperm motility (velocity and type of movement), concentration (sperm count), morphology (sperm shape), DNA fragmentation (counting of fragmented sperm), vitality (live and dead count) and acrosome reaction, which is what ultimately allows the sperm to penetrate the egg.
From on-site experience to computer technology, PBEC offers Dr. Atwood the opportunity to be at the forefront of equine reproduction, a place she has always strived to be.
“I wanted to come into a practice that had a developed program in place, but what is even more important to me is mentoring and teaching my technicians and clients about reproduction,” she said. “It is so important to make sure these techniques are shared and promoted for the continued success of veterinarians, owners, and most of all the horses.”
What is Embryo Transfer?
The most popular wave of advancement that has hit the horse sport industry over the past several years is the process of embryo transfer.
How it works:
- A donor mare and stallion, who hold the genetics of the future foal, are bred.
- At seven or eight days of pregnancy, the embryo is flushed out.
- A catheter is placed through the vagina and cervix, and an inflatable cuff on the catheter provides a fluid-tight seal.
- A lavage fluid with surfactin (added to reduce the “stickiness” of the embryo and allow it to be extracted easily) passes down through a tubing system into the uterine lumen. As the fluid swirls throughout the lumen and drains back out through gravity, it collects the embryo, which is swept back out. The fluid and embryo pass out through the tubing system into and through an embryonic filter.
- When the embryo is identified under a microscope, it is removed into a more enriched medium until the time of transfer.
- The embryo is shipped to a recipient farm where a young and healthy surrogate mare of decent size receives the embryo. That mare carries the foal to term, but it is genetically created from the donor mare and stallion.
While the process is fascinating, some may wonder why it’s necessary. According to Dr. Atwood, it relieves much of the concern owners have about sport horse breeding.
“The gestation period for a horse is 11 months, so you’re only getting one foal per year when you breed traditionally,” she said. “This allows a mare to produce multiple foals per year, but it also allows that mare to remain in competition. This process can be done on younger mares with no interruptions to their competition and training schedules.”
Horses are now being bred at an ideal reproductive age while they are still in training, which is made even more valuable by the fact that advances in equine science has prolonged the longevity of horses. While 16 or 17 was once the age of an older horse, now it’s commonly seen as the age when horses are winning in the show ring. Thanks to embryo transfer, these horses can enjoy longer, healthy careers and still produce the talent of the future.
Dr. Atwood has seen embryo transfers become popular in dressage and polo, but she has begun to see it span all disciplines, saying, “At the start of the season, I had one farm and a few mares, but now it has quickly grown to several farms with multiple mares at each. It is really taking off because people now realize it does not remove their mares from competition.”
The process not only keeps mares competing, but it allows stallions to cross continents. Frozen fertilized embryos from working polo ponies in the U.S. are now being shipped to Argentina where they are carried by mares and then trained by some of the best polo trainers in the world. On the flip side, semen can also be frozen and shipped to the U.S.
“Stallions are collected, the semen is placed with an extender and high nutrient base so the sperm has something to use for energy, and then cooled slowly until it is frozen in liquid nitrogen,” said Dr. Atwood. “Once frozen, it is theoretically good forever. Last year, I bred a mare with 1991 semen and she was successfully pregnant!”