Not right, but not lame

When a seasoned hunter starts to struggle in the show ring, the cause isn’t immediately clear. Can you identify the reason behind his inconsistent performances?

Monty was an icon on the local show circuit. The 17-year-old gelding had taken dozens of young riders through the show hunter ranks, instilling confidence with his rock-steady gaits and sensible personality. Over the years, Monty had been passed from sibling to sibling and leased to friends, but never, ever sold. He was far too valuable for that. His long-time owner, Sarah, was now an adult but would still hop on him from time to time to reconnect with her old friend.

Monty was known as a safe and reliable performer.

But on one of those rides, Sarah noticed a change in Monty. His stride seemed shorter—particularly early in a ride—and his canter rhythm less consistent. Perhaps most concerning: When going over jumps, Monty now occasionally missed distances, taking off too early or too late for a fence—something he’d never done before. From the ground, however, Monty appeared absolutely sound.

Sarah mentioned her worries to the trainer working with Monty’s current rider. He noted that the gelding had some rough rounds at recent shows that he had chalked it up to errors by his young rider. Thinking the gelding may just be tired, he gave Monty two weeks off to rest in his pasture. When he came back into work, though, he hadn’t improved. Everyone agreed it was time to call the veterinarian.

The next week Monty’s veterinarian began a diagnostic workup. The gelding didn’t have any signs of illness, such as a fever, and neurologic tests revealed he was coordinated and steady. There were no swellings in any of Monty’s joints or signs of recent injury. Watching the gelding jog, the veterinarian saw slight unevenness as Monty circled on a longe line, but no outright lameness when he traveled on a straight line.

POSSIBLE DIAGNOSES

A variety of problems could be at the root of Monty’s lackluster performance. Here are some of the possibilities his veterinarian considered.

Equine protozoal myeloencephalitis (EPM)

A progressive neurologic disease characterized by inflammation of the brain and the spinal cord, EPM is caused by Sarcocystis Neurona protozoa ingested with feed contaminated by feces from infected opossums. Most horses exposed to S. Neurona never become ill. But in some cases the organisms cross the blood-brain barrier and attack the horse’s central nervous system, leading to the weakness, incoordination and muscle atrophy. (Public domain image from Wikipedia)

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THE EXPERT'S DIAGNOSIS

Early arthritis

A lameness exam revealed signs of early arthritic changes in Monty’s joints, most likely the result of the many miles he traveled in the showring.

Based on these findings, Monty’s veterinarian determined that the gelding’s troubles were most likely the result of early arthritic changes in his joints. Monty wasn’t currently lame, but the exam had revealed hallmarks of sub-clinical joint pain: The gelding had a slightly decreased range of motion, and flexion tests induced a pain response in his hind legs.

Monty’s arthritic changes was most likely the result of repetitive joint flexion cycles—unwelcome evidence of years of honest work. Repeated stresses on his joints led to a cascade of inflammatory events: Enzymes produced in response minute injuries break down the joint’s lubricating synovial fluid, making it thinner and less protective. As this damage mounts, inflammatory fluids accumulate, leading to the pressure, pain and stiffness that are the hallmarks of arthritic joints.

The fact that Sarah, who knew Monty well, could feel changes when riding the gelding before they were evident to an observer wasn’t unusual, the veterinarian explained, adding that listening to riders is one of the best ways to catch arthritis early. Radiographs might provide more evidence of changes in specific joints, but wouldn’t influence the veterinarian’s treatment recommendations, so Sarah opted to forgo those for now.

CASE CONCLUSION

The good news was that Monty’s arthritis was caught early, which meant many things could be done to manage his condition, slow its progression and keep him comfortable.

The first step was an adjustment to his workload. Regular exercise is essential for preserving joint function, so outright retirement would do more harm than good. Instead, Monty would now only be used for equitation classes, with lower fences, and on a less stressful show schedule. In addition, shows held in arenas known to have especially hard or otherwise challenging footing, were left off Monty’s schedule—concussion from hard ground would be too hard on his joints. With his years of experience, Monty didn’t need much schooling. His work is centered on regular, light rides between shows with as much turnout as possible year-round. The goal was to keep him fit and active, without stressing his joints.

The veterinarian also recommended putting Monty on an oral joint support supplement, ideally one containing some combination of hyaluronic acid, chondroitin sulfate, glucosamine and methysulfonylmethane (MSM). Starting a supplement early, and keeping Monty on it consistently, could help protect the cartilage in his joints, keeping him sounder longer.

Medication also helped keep Monty comfortable. Long-term NSAID use comes with risks but if, after a long weekend of showing, Monty was a bit more sore than usual, a three to five day regimen of phenylbutazone could be helpful. Down the road, if a specific joint began to become more troublesome, Monty could be a candidate for therapeutic injection of hyaluronic acid, glycosaminoglycan, chondroitin sulfate or a product containing all three of these. Such injections are given to boost production of synovial fluid and encourage cartilage to heal itself and they are also thought to have an anti-inflammatory effect.

A few months after Monty’s diagnosis, with his new work routine and care protocols in place, Monty’s form returned. He is now carrying another lucky young rider to show ring glory.

Note: Monty’s story is a composite of actual case histories presented for educational purposes.

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