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.
Originally from northern California, Dr. Janet Greenfield Davis grew up competing on the hunter circuit which sparked her interest in equine veterinary medicine. She completed her undergraduate degree at California Polytechnic State University, and went on to complete veterinary school at the University of Glasgow. While in the UK, she became a member of the Royal College of Veterinary Surgeons.
After completing an internship at Palm Beach Equine Clinic in 2010, Dr. Greenfield Davis studied traditional Chinese veterinary medicine at the Chi Institute. In addition to providing western medicine, Dr. Greenfield Davis employs eastern medicine as a certified veterinary acupuncturist and Chinese herbal medicine expert.
When not seeing patients, Dr. Greenfield Davis enjoys cheering on her clients at competitions, swing dancing, and spending time with her husband, fellow Palm Beach Equine Clinic veterinarian Dr. Tyler Davis, and their two daughters. We featured Dr. Greenfield Davis nearly 10 years ago and have caught up with her to see how things have changed in a decade.
1. Our last Q&A with you was in 2015 when your girls were just babies – what’s it like now balancing your veterinary career with older kids that have interests of their own? Are horses part of their lives?
It is certainly different having older children and practicing veterinary medicine. Maisie is now 9 and Zella is 11. They do have interests of their own. Gone are the days of loading everyone in the truck and working through naptime. Now I adjust my workday to accommodate after-school sports and homework. While they sometimes enjoy riding around with me on calls they would prefer to do something else. I try much harder to take my weekends off to spend time with them. I feel like these are the years they will remember the most, and I don’t want those memories to be of their iPads. Instead, it can be of their parents prying their iPads from their little fingers to go clean the turtle tank on a bright Saturday afternoon.
The girls did attempt riding for a while, but it didn’t stick. Their horse time is preferably spent at the clinic where they can watch all their favorite vets perform procedures and then have Dr. Swerdlin make them hot cocoa. There is a secret ingredient but it is not mine to divulge.
2. Is acupuncture still a big part of your practice? How do you see it help horses in day-to-day management?
It is! My acupuncture practice encompasses about 80% of what I do. We use acupuncture for pain relief and management, post-surgical rehabilitation, vices, nervous horses, lameness, and so much more. I also work in Equine Rehabilitation to help strengthen training practices and improve agility.
3. How does working with Vinceremos Therapeutic Riding Center still hold meaning for you? What are your usual duties there?
I have been the primary veterinarian at Vinceremos for 14 years with aid from my colleagues. It is beneficial work and of course it holds meaning for me. I know many of the clients and after so many years, the Vinceremos horses feel like my own.
4. Are there still other programs outside of PBEC that you work with in the community?
I mainly volunteer at my kids’ school when I can. I have a career day coming up. I eagerly anticipate the questions asked by kindergarten to fifth grade students. They always surprise me, and we usually have a good laugh.
5. Do you work with the internship program at PBEC? What are the benefits of that program for the clinic and for you as a vet?
I do work with the internship program at PBEC, and actually, all our vets do. Our clinic trains new graduates into confident, seasoned veterinarians.
6. Have you had any additional continuing education or certifications since you became a certified equine rehabilitation practitioner?
Nothing new yet. I am currently working to further myself as an FEI delegate.
7. What do you find is most fulfilling still in your career?
The most fulfilling part of veterinary medicine is having a happy client and a happy horse. It doesn’t matter if it is a colic or helping to achieve their competitive goals. The satisfaction is knowing that everyone is healthy and happy.
8. What is something you have seen or heard about that is developing in the veterinary industry that you are excited about?
The veterinary field is constantly changing. New research is done every day. I am excited about it all!
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.
A recent popular post on PBEC’s social media was about retired Davie County, FL, police horse Charlie, who injured himself in true equine fashion – spectacularly and with no one knowing how – during the night while turned out in a field. Charlie was adopted by the mother of one of the Davie County police officers who also works for the Sheriff’s Department. They brought Charlie to PBEC to repair a large laceration on his side.
Dr. Michelle Maguire was on hand to care for Charlie and explained the steps it took to get him back to healing. Dr. Maguire and her team administered intravenous sedation in order to repair with him standing up then injected local anesthesia around the circumference of the laceration, which measured approximately 12 by 18 inches.
“This case was particularly challenging because it was a very large area with multiple flaps and went through many layers, including skin, subcutaneous tissue, and the muscle layers overlying the thorax,” said Dr. Maguire. “Luckily there was no penetration into the thoracic cavity.”
Dr. Maguire used walking sutures to close the laceration, extending from the skin flap’s deep dermis to the underlying fascia of the body wall. This approach helps eliminate
dead space to help prevent seroma formation and infection, reduce skin tension, promote wound closure, and lower the risk of dehiscence, a surgical complication where a wound ruptures along the incision after surgery.
Because the skin can’t handle tension, you can’t just suture the skin itself. Dr. Maguire also used a Jackson Pratt drain, a commonly used surgical drain that provides a constant, low suction to pull fluid from a surgical incision site to decrease swelling and reduce the risk of infection. The drain consists of a thin, rubber tube and a soft, round squeeze bulb, or “grenade” on the end that maintains negative pressure and allows for an active drainage system.
Dr. Maguire noted that Charlie’s prognosis is very good, and he is expected to make a full recovery. He has been doing well at home, and the wound has held together without dehiscence.
She added, “The aftercare protocol was a course of systemic antibiotics and anti-inflammatories, along with maintaining a compressive for the first two weeks postoperatively until skin sutures were removed.
“The horse handled everything very well,” she continued. “He was in pain the first day postoperatively, but as the inflammation subsided, he was a normal happy horse.”
The team at Palm Beach Equine Clinic is happy to report that Charlie is back home grazing. While he will have a scar, it won’t affect his quality of life, and he will have quite a story to tell his friends!
Meet PBEC Intern Valentine Prié DVM
Valentine Prié DVM earned her veterinary degree in Croatia and spent time in several equine clinics in Europe before heading to the United States in 2024 to broaden her knowledge. She’s part of the class of 2024/2025 interns at the Palm Beach Equine Clinic (PBEC) in Wellington, FL.
Where are you from?
I’m from Normandy in the northwest part of France. For the last six years, I have mostly lived in Croatia, where I did both my undergraduate and vet school work. In 2024, I moved to the U.S. and have been an intern at PBEC since July.
What is your background with horses?
I started riding when I was 5 years old. My family were ranchers, and we had a cattle and horse farm, so I was always around horses. I did mostly show jumping.
What brought you to PBEC?
I always wanted to be a vet — it was not even a question. My great-grandfather founded a vet school in France, and my brother is also going to graduate as an equine vet. It’s in the family!
I moved to Croatia shortly after turning 18 and graduated from the University of Zagreb’s vet school. During my fifth year, I spent some time in Austria at the University of Vienna. This year, I completed part of my final rotation at UC Davis in California.
I wanted to explore as many different approaches to equine medicine as possible. Things here in the U.S. are done differently, not just technique, but the approach to patient care and communication and the use of medications. My goal is to have, as much as possible, an open mind to veterinary practice.
When I complete the program at PBEC, I will head to going to Hagyard in Kentucky for a specialized internship.
What is the process of becoming an intern at PBEC?
I came to PBEC two years ago for a summer externship. After staying in touch with some previous interns and employees at the clinic, I applied last winter, had my interview in February, and in March, Dr. Swerdlin started helping me with the visa process. I began the internship in July.
What is the program like?
It’s been busy! I want to see as much as possible and experience all the areas of equine medicine — surgery, internal medicine, and ambulatory as well. It’s a really busy clinic with a high caseload and many veterinarians from various parts of the world, each withdifferent approaches to medicine and slightly different practices. That’s really beneficial for me to compare what can be done. It’s been a great learning experience. I see a lot and try to listen and remember!
What’s a typical day like for you?
Our schedule is organized on rotation, so we do two weeks of anesthesia, two weeks of surgery, two weeks of hospitalization/internal medicine, two weeks of ambulatory, and two weeks of overnight. Depending on which rotation I am on, the day is different.
Usually, you check the patients assigned to you for your rotation — I will do a full physical examination and write notes for every patient. After rounds, we get everything ready; for instance, with surgery, we bring the horse and assist with the surgery and the recovery of our patient. Then we take care of their treatment plan.
What do you do in your free time?
I’m a runner. I’m preparing for the Miami Marathon in February. I did the Toronto Marathon in 2024. And I read! I love all the French classical novels and poetry. I read a lot of equine medicine articles and books, too.
By Lindsay Berreth/Jump Media
Meghan Duncan of Ocala, FL, has worked at the Palm Beach Equine Clinic (PBEC) in Wellington, FL, since 2021. Since 2022, she’s been Dr. Paul Wollenman’s technician, traveling to Wyoming in the summer and based at PBEC in the winter, where she assists clients with polo ponies.
What is your background with horses?
I rode and showed Western pleasure as a kid. As I grew older, I got out of horses and became more involved with school and sports, so horses kind of took a back seat. I always had a love and interest for it, but I just didn’t have the resources and the time to make it happen.
I moved to South Florida in 2008 for college, and around 2020, with COVID going on and big changes happening for a lot of people, I found myself in a position where I was no longer able to work my job in hospitality, which I had been doing since I was 15.
After some personal life events had happened, I needed something to get me out of the house. My mom mentioned an animal rescue that always needed volunteers. The couple who ran the rescue were elderly, so it was difficult for them to take care of the horses. I fell in love with being around the horses again.
What brought you to PBEC?
When I was a kid, I always wanted to be an equine vet. That was my dream. It just never happened, but one night, while I was volunteering at the rescue, one of the horses was colicking. They called me to see if I could help the vet, who was coming without a technician. I got to meet the emergency vet and see how that whole process worked for the first time. I was really intrigued.
The vet came out again the next day to recheck the horse and asked me if I wanted a job. I told him, yeah, that’d be great! He needed help on the weekends. He was a large animal vet, so he did horses, cows, goats, and sheep.
I wanted to work with horses specifically, and PBEC had a job post for a hospital technician, and the rest is history. I was hired in March 2021 by Dr. Kathleen Timmins and Holly Hall.
What does your job involve?
In 2022, I had the opportunity to work with Dr. Paul Wollenman, who founded the clinic in 1981. He worked in Florida in the winter and traveled to Wyoming in the summer to continue practicing. It sounded like a dream. I really wanted to take the opportunity to start traveling again.
We go to Big Horn, WY, in the summer and come back to Florida for the winter and spring. We work on polo ponies 99% of the time. There are some clients in Wyoming who have rodeo or ranch horses we work on.
Day to day, we see a lot of lamenesses and small wounds on the polo ponies — we do a lot of ultrasounding and regenerative therapy like PRP or stem cell injections. My job is to jog the horse, to keep the horse as still and quiet as possible while being treated, and I’ll help with scrubbing joints for joint injections, bandaging, keeping the inventory up to date, keeping the truck clean and stocked, uploading information to patient files, and handling some client communications.
What’s the most interesting thing about your job?
I like any kind of emergency care just because it’s something different. You don’t know what you’re going to walk into. It’s unpredictable, and you have to think on your feet.
What do you do in your free time?
When I’m in Wyoming, I love to go trail riding with a couple of friends or hiking with my dog. Our schedule is kind of crazy in Florida, but I like to spend time with my dog, go on long adventure walks, and find somewhere to hike or trail. I also like to go to the gym, work out, and do Crossfit.
By Alice Collins / Jump Media
Hailing from Minnesota, Allison Schatzley has been an avid horse lover since she was small and has worked in the industry since she graduated from the University of Wisconsin. She joined the Palm Beach Equine Clinic (PBEC) team in the fall of 2023.
Where are you from?
I’m originally from Minnesota and completed my undergraduate degree in animal science equine management with an emphasis on animal nutrition at the University of Wisconsin-River Falls.
What is your background with horses?
I’ve been riding since I can remember, and I worked at barns cleaning stalls through high school and college. After I graduated, I pursued a career in equine nutrition, helping owners feed their horses according to their goals, such as performance, weight loss, and weight gain.
What brought you to PBEC?
A little over a year ago, I decided I needed a change. I missed being directly involved with equine care and searched for a job that could fulfill that. I found PBEC and thought I could utilize my background augment the patient care.
What does your job involve?
A typical day involves assessing the patients I’ve been assigned for the day, performing treatments at their scheduled times, such as administering medications, changing standing wraps, grooming, and helping doctors with their procedures on the hospital patients. When we get an emergency in, I’ll pull blood for lab work, place the catheter, hang the fluids, or prep them for surgery if need be.
What aspects of equine medicine interest you most?
It’s been pretty interesting to be able to tie my nutrition background to certain instances, including my favorites, the horses with laminitis. It allows me to better understand some cases.
What cases that you’ve worked on stand out?
We recently had a burn victim from a barn fire. He was the sweetest horse, and it was so rewarding when he got to return home!
What’s the best thing about your job?
My favorite part of the job is being able to spend my time taking care of the horses and making sure I’ve done all I can to ensure they are feeling the best they possibly can in their current situation and condition. At PBEC, we have a great crew for the upcoming season, and I’m excited about what this winter will bring.
What do you enjoy doing in your free time?
I love to bake! I make anything from cakes and cupcakes to pastries and breads. I bring in my creations most of the time, and I love sharing them with my coworkers. I go to the gym quite often, lifting weights and running. I also love spending time with my boyfriend and our critters at home.
To learn more about the full range of services offered at Palm Beach Equine Clinic, call 561-793-1599 or visit https://equineclinic.com/.
By Alice Collins / Jump Media
Originally from Corrientes in the north of Argentina, Lujan Montiel completed her veterinary degree in her home country in 2016, then specialized in treating polo ponies before joining the intern program at Palm Beach Equine Clinic (PBEC).
What is your background with horses?
Over the past eight years, I have worked primarily with polo horses, focusing on their care and management in a field setting — a very different scenario from Wellington and of course from a hospital environment.
When and why did you decide you wanted to become an intern at Palm Beach Equine Clinic?
Since 2023 I have been in contact with PBEC, exploring the possibility of joining the 2024-2025 internship program. My interest in this internship stems from a desire to broaden my expertise and gain a comprehensive view of equine medicine. I aim to specialize further by integrating the intensive care practices performed at the clinic, in addition to learning from the high-level professionals and advanced technology that the hospital offers for both hospitalized and outpatients.
What does the internship program involve?
The program involves rotations through all areas of equine veterinary medicine, including internal medicine, surgery, anesthesia, sport medicine, ophthalmology, and dentistry. The structured rotations, changing every two weeks, provide a unique opportunity to develop skills across multiple disciplines.
What does a typical day look like for you at PBEC?
A typical day at PBEC begins with checking all my patients, performing physical exams, and updating their medical notes. At 8:30 a.m., we have rounds where we discuss cases with the doctors. Occasionally, we have scheduled surgeries, which always start at 9 a.m. Depending on the day and the rotation I’m in, I could be working in surgery, anesthesia, in the hospital, or ambulatory work with one of the clinicians. Therefore, each day can be quite variable and diverse, offering a broad range of experiences.
What aspects of equine medicine interest you most, and what types of cases do you find most rewarding?
The area of veterinary medicine that most interests me is internal medicine. Since my arrival in late June, I have had the privilege of treating a wide variety of cases, including laminitis, colic, neurological patients, diarrheas, and endotoxemia cases, among others.
What is one of the most interesting cases you have worked on?
The cases that I’ve found most interesting and educational have been colic cases due to their variety and the protocol-based management that the clinic employs. There were a series of four colic cases (one next to the other), and all of them were resolved surgically. All of these cases involved a very rare condition called mesocecum entrapment, which prompted significant research into this topic at the clinic.
What’s your favorite part of the job/the biggest thing you have learned?
What I enjoy most about working at PBEC is the willingness of the clinicians to share their expertise in various fields, whether it’s sports medicine, surgery, anesthesia, or internal medicine. Their dedication to teaching ensures that the internship is as rewarding and beneficial as possible, allowing us to truly make the most out of this intensive year of work. Additionally, I have been fortunate to work with a group of interns who have excellent values of camaraderie, making everything lighter and easier when things get busy at the clinic.
When not at PBEC, what do you enjoy doing in your free time?
During my days off, I try to explore the surrounding areas of Wellington, including the beach, as it’s a new country for me, and I love taking the opportunity to enjoy the coastline.
To learn more about the full range of services on offer at Palm Beach Equine Clinic, call 561-793-1599 or visit www.EquineClinic.com.
Fernando J. Marqués, DVM, Diplomate ACVIM, Diplomate ACVSMR
The exceptional athletic abilities of horses can be attributed to several factors, including physiological adaptations, some of which are influenced by training. Muscles, and all cells in the body, require energy to function. Energy from food (carbohydrates, fats, and proteins) is not directly transferred to muscles for biological work. Instead, it is converted into an energy-rich substance known as ATP. The oxidation of carbohydrates, fats, and proteins is the process that produces ATP. There are three main energy systems that supply ATP to the cells: the immediate energy system, the short-term energy system, and the long-term energy system.
The immediate energy system relies on high-energy phosphate sources and plays a crucial role during intense physical activities of short duration that require immediate fuel. These high-energy phosphates are quickly depleted, typically within 20 to 30 seconds of maximum exertion, similar to what happens in humans.
The short-term energy system generates ATP mainly from stored muscle carbohydrates called glycogen. This process does not require oxygen, which is why it is referred to as anaerobic metabolism, leading to lactate accumulation within the muscle cells.
The long-term energy system, or aerobic system, produces ATP during prolonged, intense physical activity. This process requires oxygen, hence the name aerobic metabolism. In this system, fats are a significant fuel source.
The contribution of each energy system and fuel source (carbohydrates, fats, and to a lesser extent proteins) varies depending on factors such as exercise intensity and duration, training status, muscle fiber composition, and oxygen supply to the muscles. Understanding these factors is crucial, as exercise is generally categorized into aerobic/endurance (low intensity over a long duration) and power/strength (high intensity over a short duration). In practice, pure endurance or pure strength activities are rare, and most sports combine elements of both.
Additionally, muscles adapt to specific exercises and sports, which triggers the development of particular muscle fibers that utilize different fuel sources and energy systems to produce ATP.
In equestrian sports, no discipline is exclusively anaerobic or aerobic. Most sports require a combination of both energy systems. For example, racehorses and western performance horses engage in high-intensity, fast-paced activities for short periods, primarily relying on anaerobic metabolism. Conversely, show jumping and polo horses mainly engage in aerobic exercise but switch to anaerobic metabolism to meet the intense energy demands of their sport. Eventing and endurance racing horses, on the other hand, rely predominantly on aerobic metabolism to sustain their energy levels over prolonged periods of activity.
Designing an effective training program for a horse requires considering the optimal adaptation of muscle fiber composition to enhance metabolic function and improve performance in the specific sport.
References:
- Hinchcliff K., Geor R., Kaneps A. Equine Exercise Physiology- The Science of Exercise in the Athletic Horse. Saunders
- McArdle W., Katch F., Katch V. Exercise Physiology. Wolters Kluwer, 8th Edition.
- https://equineclinic.com/medical/understanding-energy-support-for-the-performance-horse/
By Alice Collins / Jump Media
The warm late summer of 2024 has paved the way for more mosquitos and heralded the start of West Nile Virus (WNV) and Eastern Equine Encephalitis (EEE) season for both horses and humans. WNV and EEE are both equine encephalitis viruses spread by infected mosquitos. They can cause severe brain inflammation and neurological issues in humans and horses and can be fatal in unvaccinated or under-vaccinated equine populations.
With almost daily cases of WNV in horses being reported in several U.S. states throughout August 2024, plus news of humans contracting the rare but extremely serious EEE virus, people are rightfully concerned about how to protect their animals and themselves from both WNV and EEE. The Wellington, Florida-based Palm Beach Equine Center (PBEC)advises on what you can do to minimize the risk of exposure and infection.
WNV and EEE by the Numbers
Both WNV and EEE circulate in the environment between mosquitoes and birds and are spread to horses and humans by the bite of an infected mosquito. However, even though they get sick, humans and horses are dead-end hosts that do not, in turn, spread these viruses back to mosquitoes that bite them.
Since 1999, more than 27,600 U.S. horses have been confirmed to have WNV, with an estimated fatality rate of 30-40%. With yearly activity of around 300 equine cases in the U.S., WNV is now considered endemic, persisting at a consistent level with fairly predictable rates of infection and spread.
EEE, also known as sleeping sickness, causes inflammation of the brain and spinal cord. Mortality can exceed 90% in unvaccinated horses and is lower in horses with partial protection or previous vaccination. Death usually occurs within two to three days of the onset of signs. Horses that survive may have permanent neurologic deficits.
While the diseases sound alarming, the good news is that vaccination is a very effective barrier for your horse. EEE and WNV inoculations are considered core vaccines by the American Association of Equine Practitioners. Annual injections for all horses, preferably in the spring before mosquito season, are strongly recommended. Initial vaccination is followed in four to six weeks with a booster, with yearly revaccination thereafter. Horses living in areas with mosquitos year-round may need EEE vaccinations two or three times a year for full protection.
Clinical Signs
The clinical signs of the two illnesses are almost identical, and can include:
- Depression and anorexia without fever when initially infected
- Mild low-grade fever in about 25% of affected horses with WVN
- Moderate to high fever in horses with EEE
- Lack of appetite
- Lethargy/drowsiness
- Neurologic signs, the onset of which are frequently sudden and progressive
- Periods of hyperexcitability, apprehension and/or drowsiness
- Fine tremors of the face and neck muscles
- Cranial nerve paralysis — facial paralysis and weakness of the tongue are very common
- Head tilt, droopy lip, muzzle deviation
- Weakness, ataxia, and lack of coordination in one or more limbs
- Complete paralysis of one or more limbs
- Colic
- Inability to stand
Diagnosis and Treatment
A veterinarian will diagnose both WNV and EEE by testing the horse’s serum, a component of whole blood. There is no cure for either virus, but horses showing clinical signs are given supportive care.
Prevention
Aside from vigilant vaccination suitable for the horse’s environment, there are other measures owners can take to prevent infection from both WNV and EEE. They include frequent use of insect repellent, which should be reapplied after rain, keeping horses stabled at night, minimizing standing water, and eliminating areas in which water can collect, such as leaf piles or old tires.
PBEC President Dr. Scott Swerdlin advises, “We can vaccinate against all these diseases, and it’s really important to remember that it’s not just the first set; it takes at least two injections for the horse to develop immunity.”
Swerdlin also points out that horses traveling into an affected region can be put at far greater risk, adding, “People who bring horses to the U.S. from South America or Europe are exposing them to different diseases than they are accustomed to in their native country. They should vaccinate the horses immediately on arrival and then, after the first vaccine, every 12 months. In Florida, where there is a huge mosquito population, we recommend vaccinating against EEE and WNV, as well as rhinovirus, every six months for maximum protection.”
There are no approved human vaccines for WNV or EEE. Personal protective measures include using mosquito repellents, wearing long-sleeved shirts tucked into long pants, and limiting time outdoors from dusk to dawn. Using air conditioning and installing screens further decreases the risk of exposure.
For additional questions, veterinary assistance, or to book your horse’s vaccinations, call Palm Beach Equine Clinic at 561-793-1599.