Tag: reproduction
By Lindsay Berreth / Jump Media
If you have a performance mare that you wish to breed without interrupting her career, embryo transfer is a viable option. Palm Beach Equine Clinic (PBEC) in Wellington, FL, offers an extensive range of assisted and advanced reproductive procedures, including embryo transfer. With spring fast approaching, now is the time to plan.
PBEC President Dr. Scott Swerdlin highlights the advantages of the embryo transfer process, which has been utilized since the 1970s. This method is especially beneficial for sport horse mares that cannot afford to take time off for pregnancy. By using embryo transfer, you can continue riding your best mare while simultaneously breeding for your future champions. Additionally, embryo transfer is a viable option for mares with high genetic merit who cannot carry a foal. Some mares may have orthopedic issues that would be exacerbated by the extra weight of pregnancy, while others may have significant reproductive challenges, such as chronic uterine infections or a fibrotic uterus, which hinder their ability to conceive or support a developing pregnancy.
The first step in the embryo transfer process is embryo production. For this article, we are focusing on traditional in vivo embryo production vs in vitro embryo production. In vivo embryo production requires the donor mare to be bred, conceive, and produce an embryo that can then be transferred to a recipient mare. This necessitates the mare being off any hormones like Regumate® (altrenogest) or long-acting progesterone as they suppress the mare’s estrus cycle.
Strategic breeding management is essential to minimize disruptions to a mare’s training and competition schedule. This may include hormonal manipulation of the mare’s reproductive cycle, a series of reproductive examinations performed using transrectal palpation and ultrasound, a uterine culture and cytology, and breeding the mare by artificial insemination or via natural cover. It is also crucial to document the day and time of ovulation. Whether using fresh, cool-shipped, or frozen-thawed semen, the day and time of ovulation need to be documented to plan for the second and third steps of the process: embryo flush and transfer.
“Knowing the day of ovulation is important,” explained Dr. Swerdlin. “In the mare, fertilization and conception occur in the oviduct, where an embryo will remain for approximately 6 to 6.5 days before migrating to the uterus. Not knowing the day of ovulation might mean that the embryo is still in the oviduct at the time of the uterine flush. Conversely, if the embryo is further along in development, it becomes larger and more fragile, which decreases the chances of a successful outcome.”
To minimize disruptions to the mare’s schedule, most of the process can be performed on-farm, or owners can elect to come to PBEC on an outpatient basis. Veterinarians will closely monitor the mare’s estrus cycle to determine the optimum time for breeding, maximizing the chance of achieving a pregnancy.
“To improve our chance for success, once we determine that the mare is ready, the dominant pre-ovulatory follicle is stimulated to release the oocyte (egg) by administering an ovulatory agent,” stated Dr. Swerdlin. “This ovulatory agent mimics the mare’s naturally occurring hormonal process, and when used appropriately, the majority of mares will ovulate within 24 to 48 hours post-administration.
“Timing the insemination in relation to ovulation is key to success,” he continued. “This is especially true when using frozen semen. For mares that will be inseminated with frozen-thawed semen, we suggest that they arrive at the clinic the same day that the ovulatory agent is administered. This ensures that we can inseminate the mare as close to the point of ovulation as possible.”
The next step is embryo recovery, which is performed 6.5 to 8 days post-ovulation. “The mare will come to the clinic, and the process takes about an hour,” said Dr. Swerdlin. “During this procedure, the donor mare’s uterus is flushed with several liters of embryo flush media. This fluid is recovered and filtered through a special embryo filter to capture the embryo.”
After the embryo is retrieved, it is washed and graded to determine embryo quality. Embryos are graded on a 4-point scale, which 1 indicating excellent quality and 4 indicating a degenerate or dead embryo. Finally, the embryo is prepared for either direct transfer into a recipient mare, shipment to a recipient herd, or frozen for future use.
The final step in the process is the embryo transfer, which requires careful coordination. The success of this procedure is heavily dependent on selecting a suitable recipient mare, taking into account factors such as the mare’s age, size, maternal behavior, synchronization, and overall reproductive health.
“Owners can provide their own recipient mare, but we often recommend that mare owners utilize a leased recipient mare,” noted Dr. Swerdlin. “Numerous recipient herds are located throughout the country, with the closest ones being in the Ocala area. Currently, recipient mares are in very high demand, and each herd has a limited number of contracts available per year. One key advantage of using a recipient herd is that it allows multiple mares to be synchronized to match your individual mare’s ovulation date rather than relying on a single client-owned recipient. For those who prefer to use their own mare, our reproductive specialists at PBEC can manage the synchronization of the recipient mare and perform the embryo transfer.”
The embryo transfer procedure takes place at the clinic. The recipient mare is gently restrained in stocks with the aid of mild sedation. The embryo is carefully loaded into a transfer gun, which is guided trans-cervically into the mare’s uterus. Once the position has been confirmed, the embryo is deposited into the base of the uterine horn. A reproductive ultrasound is performed between three to seven days afterward to assess the uterine environment and confirm that the embryo is developing properly. Recipient herds will often report pregnancies between day seven to nine after transfer.
Dr. Swerdlin noted that the success rate for embryo recovery varies based on the type of semen used and the donor mare. “When using fresh and cool-shipped semen, embryo production rates can reach between 70% and 90%,” he said. “With frozen-thawed semen, the rates are lower, ranging from 50% to 60%. Overall, the success rate of the embryo transfer ranges from 70% to 90%, depending on the quality of both the recipient mare and the embryo.”
Embryo transfer provides an effective and practical solution for sport horse owners and breeders. As the demand for top sport horses increases, it continues to be a valuable tool for those looking to breed that special mare.
For more information on embryo transfer and other reproductive services offered at PBEC, visit www.equineclinic.com or call 561-793-1599.
By Lindsay Berreth / Jump Media
With modern veterinary technology, there are several ways to breed your treasured mare should she have trouble getting pregnant or carrying a foal. Intracytoplasmic sperm injection, or ICSI, an alternative to traditional embryo transfer is becoming a popular option for the sport horse mare.
According to Dr. Justin McNaughten BVMS, DACT, the equine reproductive specialist at Palm Beach Equine Clinic (PBEC) in Wellington, FL, the ICSI procedure was originally developed to help overcome subfertility in mares and stallions. The first ICSI foal was born in 1996, and since then the procedure has gained popularity amongst breeders for mare and stallion owners alike.
Before ICSI, many breeders’ options for their mare were limited to embryo transfer, which involves breeding the donor mare, flushing the donor mare’s uterus, and then transferring the embryo into a recipient mare that has been synchronized to the donor mare’s cycle. For stallions with limited semen reserves, there wasn’t much that could be done. However, ICSI has become an invaluable tool for preserving sperm from deceased stallions or stallions with limited semen availability as the procedure uses less sperm to fertilize an egg.
A significant advantage of ICSI for sport horse mares, compared to traditional embryo transfer, is that the procedure can be performed at any stage of the estrous cycle, regardless of the natural breeding season. This flexibility allows mares to concentrate on their competition schedules and minimizes disruptions to their training or show commitments.
During the procedure, oocytes, or eggs, are collected from a donor mare’s follicles on the ovary. “It is a valuable option for mares with uterine, oviductal, or cervical disorders that would not allow the mare to be an embryo donor,” said Dr. McNaughten. The ICSI procedure bypasses most of the reproductive tract and goes straight to the source for the oocytes (shown below), the ovary.
Palm Beach Equine Clinic offers the first stage of the procedure, the oocyte aspiration or egg retrieval. Vets will ship the eggs to an ICSI lab to complete the maturation and fertilization processes. During aspiration, mares are sedated and restrained in stocks. The veterinarian passes a long handle ultrasound probe which also houses the aspiration needle into the mare’s vagina. The ovary is stabilized by the veterinarian per rectum to allow for visualization of the ovary and the follicle. The needle is inserted into the follicle; the fluid is aspirated, the wall of the follicle is scraped, then the follicle is flushed and the fluid is aspirated. The scrapping, flushing, and aspirating are repeated multiple times to help dislodge the immature oocyte. The flush fluid that is recovered is then filtered, and any oocytes that are recovered are prepared and transferred into a special holding and shipped off for the next step. The entire process is known as transvaginal oocyte aspiration (TVA) in the US or ovum pick-up (OPU) in other parts of the world.
While the procedure is becoming more routine, it does carry some risks. To safeguard against any risks the procedure is only performed at the clinic. All mares are provided pain relief during the procedure and the following day. “We recommend that mares stay overnight at the clinic to be monitored for any signs of discomfort,” noted Dr. McNaughten, “and most mares return to full work within the week following the procedure.”
Once an ICSI lab receives the egg or eggs, they are put into a maturation media and monitored for 24 hours. “The eggs that we’re taking from the mare are immature, they’re incubated in a specialized maturation media,” said Dr. McNaughten. Each oocyte that matures, is then fertilized with a single sperm cell. “That’s the process of the intracytoplasmic sperm injection or ICSI. If all goes well, the fertilized oocytes are monitored to see if there’s any cellular division or cleavage, which means that fertilization was successful. Those will be monitored for the next 7-10 days until they reach the blastocyst or embryo stage.”
Maturation, fertilization, and embryo production rates can be affected by numerous factors including bred, age, season, level of work, semen quality and whether it is cool shipped or frozen semen. On average 50 to 60% of eggs will mature and be suitable for fertilization. Intracytoplasmic sperm injection laboratories report 70 to 80% of oocytes fertilized typically divide and grow, and 20 to 30% of fertilized oocytes will grow in culture to the blastocyst stage for embryo transfer. The final step in the ICSI process is to transfer the embryo to a recipient mare or freeze it. According to Dr. McNaughten, 60 to 70% of transfers are successful.
In our hands ICSI has become an invaluable tool for in vitro produced embryos not only on the mare side but for select valuable stallions. “To put it into perspective, in a conventional frozen semen breeding dose, the minimum dose is 250 million progressively motile sperm for one breeding. With ICSI, one sperm is used to fertilize one egg,” he explained. “We have also been very successful in producing embryos and foals using frozen semen from a deceased stallions that previously had not produced embryos through conventional breeding management with the same frozen semen.”
Palm Beach Equine Clinic is here to help you achieve your breeding goals. Our veterinarians specialize in breeding and reproduction and utilize the latest technology to ensure a seamless experience for both you and your mare. Contact us today at 561-793-1599 to schedule an appointment or to learn more.
Wellington, FL – March 18, 2022 – Palm Beach Equine Clinic (PBEC) is excited to announce a new partnership with Hagyard Equine Medical Institute (HEMI), one of the leading equine medical centers in advanced reproductive medicine. Through the partnership, equine reproductive specialists will work collaboratively with the team at PBEC to expand upon the traditional services currently being offered.
While Dr. Justin McNaughten and Dr. Robert Smith will lead the team in Wellington, Dr. Karen Wolfsdorf, Dr. Karen Von Dollen and Dr. Kristina Lu from HEMI will provide assistance with advanced reproductive services. Dr. McNaughten received his BVMS from the University of Glasgow, School of Veterinary Medicine in Glasgow, UK. After completing a fellowship and residency he became a board-certified theriogenologist working in early embryonic loss, mare infertility, and stallion behavior as well as general reproduction and assisted reproductive techniques.
“It’s a new adventure using the equine reproductive specialists from HEMI to work collaboratively with Palm Beach Equine,” McNaughten commented. “The big thing is to tap into the more advanced artificial assisted reproductive techniques specifically for our sport horse and competition mares.”
Dr. Wolfsdorf emphasized that the partnership between the two clinics helps to provide a streamlined approach to their equine patients throughout the year. “Horses travel, so when they move north, to Kentucky per se, they’ll get the continued specialized care. It may not be the same individual but as a team, there will be open communication,” she explained.
One of the advanced services that will be incorporated into PBEC’s reproduction program is Transvaginal Aspiration (TVA) of the oocyte from the mare’s ovary. Oocytes are processed and shipped to a specialized Intracytoplasmic Sperm Injection (ICSI) laboratory. The ICSI procedure involves the micro-injection of a single sperm cell into a mature oocyte to produce an embryo. Dr. Von Dollen explained, “Oocyte aspiration offers an opportunity to salvage the reproductive potential of subfertile mares or stallions. Furthermore, embryos can be produced without the need to interrupt a mare’s competition schedule for insemination and embryo flushing,” she added.
Palm Beach Equine Clinic will offer these new advanced techniques along with all of the traditional services whether at the equine hospital or in a private barn. With expert care and advanced practices, PBEC maximizes the likelihood of a successful pregnancy and to produce the talent of the future.
To learn more about the routine and advanced reproductive services offered this season contact PBEC at 561-793-1599, HEMI 859-255-8741 or visit www.EquineClinic.com or www.Hagyard.com. Follow Palm Beach Equine Clinic and Hagyard Equine Medical Institute on Facebook and Instagram to see more about the clinic, its vets, and those they serve.
Breeding the Modern Way
Palm Beach Equine Clinic’s Own Dr. Katie Atwood Discusses a 21st Century Take on Equine Reproduction
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 joined Palm Beach Equine Clinic, based in Wellington, FL, in June and brought her passion for reproductive work with her to 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!”
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 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 breeding their sport horse mares.
“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!”
What’s Next at Palm Beach Equine Clinic
Palm Beach Equine Clinic underwent significant facility renovations over the last year, which included improvements to their onsite breeding shed. Now covered from the heat and inclement weather like an indoor arena, the shed boasts 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.”
Additionally, Palm Beach Equine Clinic recently incorporated 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 onsite experience to computer technology, Palm Beach Equine Clinic 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 horses.”
Speak with Dr. Atwood about breeding your horse by filling out the form below
As the leading equine veterinary hospital in the southeast, Palm Beach Equine Clinic is proud to bring our clients videos on specific topics of interest. This video features equine reproduction specialist, Dr. Robert “Bob“ Smith discussing Artificial Insemination for horses.
About Dr. Robert Smith
Dr. Smith is a 1975 graduate of the University of Georgia who lives in Royal Palm Beach and has been practicing for 30 years. Dr. Smith is a renowned veterinarian who specializes in advanced reproductive services. He advises and consults with clients on advanced fertility techniques, such as embryo transfers, and oversees a complete frozen semen program, from collection to storage and worldwide distribution.