In 2017, an exercise-testing protocol was defined for reining horses. How can that help reining athletes today?
By Kristin Pitzer
Pre-purchase exams are fairly routine before buying a horse, and you likely stay ahead when it’s time for Coggins tests and yearly vaccinations. But have you considered using an exercise test to check your reiner for subclinical signs of disease?
Up until a few years ago, doing such a test on a reining horse wasn’t possible, as there were few studies reporting exercise testing in Western performance horses. In 2016, Dr. Cristobal Navas de Solis, former clinical assistant professor in equine internal medicine and ultrasound at Texas A&M University, set out to create a standardized exercise-testing program for reining horses and document abnormalities.
The study, called “Standardized exercise testing in 17 reining horses: Musculoskeletal, respiratory, cardiac, and clinicopathological findings,” established a reference range for the general reining horse population. Navas chose reining-specific maneuvers, such as the sliding stop and turnaround, for horses to perform, and measured their vitals during the test.
“We decided to do that study because it seemed like this exercise testing in horses is very specific to discipline,” Navas said. “Many of the diseases that you test for in an athlete, you have to see the horse doing whatever he’s going to be doing for a ‘living,’ and the clinical science will be specific for that type of work.”
After the study was completed, Navas and his colleagues concluded that an exercise-testing protocol can be used as a preventative tool for reining horses to discover underlying problems that are asymptomatic. Correcting those issues before they affect your horse’s performance can point him toward a happy, healthy career.
Creating an Exercise Test
The reining exercise testing examinations, which took place April 25–29, 2016, involved historical questionnaires; general physical exams; and myriad tests on gait analysis, the upper airway, and the heart. Navas, now assistant professor of cardiology ultrasound and medicine at University of Pennsylvania, worked with two other Texas A&M veterinarians—Dr. Canaan Whitfield-Cargile, assistant professor of large animal surgery, and Dr. Sarah Sampson, clinical assistant professor of equine sports medicine and imaging. Each veterinarian conducted a specific aspect of the study.
“These comprehensive exercise tests are a little bit different than assessing other types of clinical problems,” Navas said. “You need to evaluate all body systems because often it’s not that they have one problem causing poor performance; it’s a combination of a few small problems that perhaps independently the horse is able to tolerate, but once combined, cause performance problems.”
Navas and his team looked at a population of 17 university-owned, low-level performing reining horses. Of those, 15 were Quarter Horses and two were Paints. There were 12 geldings, four mares, and one stallion. All were around 10 years old. One horse was removed from the study after the musculoskeletal exam due to severe lameness.
Musculoskeletal issues were the most common of all the disease processes tested. All horses in the study showed some degree of lameness while being walked or trotted in-hand during the musculoskeletal exam. The lamenesses ranged from very mild, or grade 1 on the American Association of Equine Practitioners’ lameness scale, to horses that had mild lameness at a walk, or grade 4.
“The population of horses we used were our university-owned horses, which are a lower level than the reiners that are competing in NRHA events,” Sampson said. “Most of our horses are donated to the program because of performance issues, which are often lameness issues that the owners no longer want to try to manage or are unable to manage. So, it’s a different population than what you might find if you went to a reining show and sampled that population of horses.”
Navas said, in general, the most common cause of poor performance in all horses is lameness. He’s found the same to be true in anything from Thoroughbred racehorses, to dressage horses, to horses that compete as three-day eventers.
“We know that a lot of these horses that are performing aren’t truly 100% sound, but they’re functionally sound, so they’re able to do their jobs even though they have issues in their front feet, hocks, or stifles that we’re able to manage,” Sampson explained. “Some horses do end up being retired because of performance-limiting lameness.”
After Sampson performed a physical exam on the horses and assessed their gaits for abnormalities, the horses were tacked up to be ridden through the exercise test. Rather than just a saddle and bridle, most horses wore other gear such as halter-mounted dynamic endoscopes and electrodes secured with glue to monitor their heart rates and rhythms.
Each horse was ridden in an 80-by-50-meter dirt arena by his usual rider, performing a 30-minute exercise routine modified from a previously reported study. They began at rest by measuring heart rate, respiration rate, temperature, and blood lactate. Each horse worked to the left, then to the right, spending five minutes each at a walk, trot, and lope, then galloping for one minute.
After the horses stopped, test administrators measured blood lactate, and horses were walked for one minute. Each horse then performed four sets of four spins, walking one minute between each set. Next, the horse performed two sets of two stops, with an 80-meter gallop between stops, then walked for one minute between sets.
After that, technicians measured blood lactate, packed cell volume (percentage of red blood cells), and respiration rate. Each horse was walked for 10 minutes, after which temperature, amount of sweating, and heart rate were recorded.
The Results
Not all horses tolerated the use of the dynamic endoscope—a camera on a tube placed in the horse’s throat while the horse is performing. Those that did, though, proved the device valuable, as it offered a glimpse into how those horses’ airways functioned during reining work.
“Normally, a horse comes in, stands in a set of stocks, and you put the camera down his throat so you can see the function. But, obviously, the airway functions differently in the horse when he’s standing still versus when he’s performing,” Whitfield said. “[With the dynamic endoscope], you can evaluate the function of the airway when a horse is actually performing because that’s when it matters.”
That kind of evaluation had never been done in a population of reining horses prior to this study. Whitfield’s purpose in using this tactic was to describe the airway’s function and see what abnormalities existed while the horses were working. Whitfield found upper-airway abnormalities in several horses, even in some that didn’t demonstrate signs of discomfort. The horses were experiencing dynamic collapse of one or more of their soft-tissue structures, meaning their throats partially closed up when they tried to take deep breaths while running.
“I think [this study] suggests upper-airway abnormalities may exist in this population of horses and could certainly affect performance,” Whitfield said. “The clinical signs they might see with dynamic airway collapse include coughing during exercise, exercise intolerance, and trouble recovering from exercise. It can even manifest itself as behavioral problems, because if you can’t breathe, it becomes a bit of a stressful situation. Some horses that have this chronic upper-respiratory problem won’t do their jobs anymore.”
Because upper-airway problems can present in different ways, it’s easy to mistake them with musculoskeletal issues. If a horse seems sour and doesn’t want to do his job, you might think he’s suffering from a lameness issue. Therefore, complete exercise testing can be more valuable than only a lameness exam, as it offers a more comprehensive look at the horse.
“Looking at the whole horse is really important,” Whitfield said.
Much like airway abnormalities can be mistaken for lameness issues, heart problems might present as labored breathing, necessitating a full body check. Navas performed blood work, monitored echocardiograms, and observed resting and exercising electrocardiology. He said heart issues were least likely to be a cause of poor performance in the Quarter Horse between the other areas studied, but noted that the presence of arrhythmias or rhythm variations is common in equine athletes.
Through the use of bloodwork, researchers discovered that one horse, after exercise, had an underlying myopathy, or a muscular disorder due to the dysfunction of muscle tissue. The horse was diagnosed with polysaccharide storage myopathy, or PSSM Type 1.
“In some of these horses, we were able to identify underlying issues that we didn’t know about and that weren’t evident to the horses’ riders,” Sampson said. “Some of these things are subclinical, but if you deal with the subclinical issues, it could prevent a bigger issue from coming up in the future or maybe increase the potential ability of the horse to perform.”
Implications for Reining Horses
Because this preliminary standardized exercise testing study was performed in lower-level reining horses, Navas is interested in testing a different type of reining horse population, such as the horses that compete in aged events or those that enter the show pen in ancillary classes on a frequent basis.
Like human athletes, horses in those categories of competition tend to be in a structured training program and endeavor to perform at their top levels consistently.
“It’s almost unthinkable for a human athlete that performs at a high level to not have a sports medicine doctor evaluate that person at the beginning of the season to make sure they’re healthy, will tolerate training, and will get to the important part of their season in the best condition,” Navas said. “In horses, it seems like it’s not a common habit to practice preventative medicine from that standpoint.”
After performing the study, Navas concluded that a standardized exercise test in reining horses is feasible. He also added that future studies are needed to define whether this protocol can be successfully used to diagnose and manage poor performance as well as to improve the health and welfare of reining horses.
However, there are two cons to exercise testing, Navas acknowledged. One is that more than one person needs to be involved with the test, as the test aims to detect small problems that may not be visible to the naked eye. Therefore, it’s best to have a specialist involved. Second, exercise testing costs money, though some may consider that money well spent when it comes to futurity prospects or favorite show pen mounts.
“If you have a horse you want to compete at the maximum level, [exercise testing] will allow you to detect problems early on that are perhaps small problems and not causing you big issues today, but if you don’t take care of them today, they may cause you bigger problems that could be an issue in the future when you have your big goal for the season,” Navas emphasized.
“We do think there are some underlying issues that are probably present in a number of performing horses, and the question is, if we address those issues, could you possibly increase the ability of the horse to perform?” Sampson asked. “If we identified an upper-airway issue and dealt with that, maybe the horse actually has more potential than we’re appreciating if we find these underlying issues that aren’t readily apparent to us without looking.
“We’re trying to be really proactive with these animals that are amazingly athletic, trying to find problems before they actually start impacting the career success of the animal,” she concluded.
