Cover Story | Orthopedics

Are horses really naughty or unwilling?

By Marie Rosenthal MS

Recent studies have shown that a horse’s negative behavior may be related to pain, according to
Sue Dyson, MA, VetMB, PhD, DEO, DECVSMR, who spoke at the ACVIM Forum 2026 in Seattle.

Unlike humans, equine behavior is not premeditated, she added. “Horses don’t decide I’m going to be a grumpy horse today.”

Many riders attribute negative behaviors in their horses without questioning what might be behind them, according to Dr. Dyson, who, with her colleagues, developed the Ridden Horse Pain Ethogram (RHpE), a tool for assessing musculoskeletal pain. Instead of excusing the behavior, they should ask: Are there genuinely grumpy, lazy, naughty, spooky, tense or unwilling horses, or are they in pain? (Animals [Basel]. 2023;13[12]:1940).

Ridden Horse Pain Ethogram
“Horses are prey animals, so they have to have an innate reaction to danger,” she explained (Animals 2025;15:399). “They don’t want to be the lion’s lunch.”

Dr. Dyson and her colleagues developed the RHpE because horses adapt their behaviors to conceal pain. For instance, they might shorten their step or reduce their range of motion, and these adaptations often go unrecognized by riders and trainers, or are attributed to misbehavior. So many owners don’t seek professional advice until the problem has escalated, making it more difficult to manage.

“I believe that identification of the problems and appropriate treatment and management will result in huge improvements in the horse’s performance,” she said. By improving its rideability, trainability and the rider’s position in the saddle, the rider’s comfort, confidence and safety will increase, too.

“We need to learn how to listen and understand what they [horses] are trying to tell us,” she said. Studies from the United States and Europe have shown that owners frequently do not appreciate pain in their horses. More than 50% of sports and leisure horses were lame, although owners did not recognize it (Animals [Basel]. 2024 Jun 20;14[12]:1831). Even veterinarians, who are trained to spot musculoskeletal issues, may miss lameness or gait dysfunction if the horse is only looked at in hand.

“Horses can appear non-lame in hand, but exhibit lameness or other gait dysfunction such as an abnormal canter when they are ridden,” she said, so it is important to put the horse through its paces under a rider.

In 1 study of 148 horses believed by their owners to be working comfortably, 28% were lame in hand, 62% were lame when ridden and 60% showed gait abnormalities in canter, according to Dr. Dyson (Equine Veterinary Education. 2022;34[2]:84-95).

“This is an important concept because, as a veterinarian, you must not make a judgment that the horse is non-lame just by evaluating it in hand and on the lunge—it must be seen ridden.”

When developing the RHpE, Dr. Dyson and her colleagues watched videos of more than 100 lame and non-lame horses to determine behaviors that might signal pain. They developed a list of 117 behaviors, which was then fine-tuned into a list of behaviors most commonly associated with pain. They found 24 behaviors—most are 10 times more likely to be seen in a lame horse than in a non-lame horse, according to Dr. Dyson. They also found that an RHpE score of 8 or more was likely to reflect musculoskeletal pain, but there are some lame horses, particularly those with recent pain onset in a single limb, which may have an ethogram score that is lower than 8, she warned.

The behaviors are divided into facial, body and gait markers. The team examined the behaviors of lame horses before and after diagnostic anesthesia or nerve blocks and found a highly statistically significant reduction in scores after pain was removed.
“This provides us further evidence that a ridden horse pain ethogram score of 8 or more is likely to reflect musculoskeletal pain. And it also tells us that contrary to common belief, these behaviors are not habitual. When we remove the pain, the majority of the behaviors either disappear or are significantly reduced in their frequency of occurrence,” she said.

Who can use RHpE?
Once the RHpE was proven effective, they tested its use among lay people and compared their assessments of 42 videos in which the horse was either lame or had diagnostic anesthesia. The non-professional scores were compared with the results of a trained assessor, the gold standard.

“All the assessors gave highly significant decreases in the Ridden Horse Pain Ethogram scores after the abolition of lameness,” Dr. Dyson explained. Although the trained assessor was better at picking lameness, the scores by the non-trained assessors were statistically similar to the trained assessors’ scores.

Threshold values of 6, 7, 8 and 9 out of 24 were assessed, but an RHpE score of more than 8/24 gave the highest accuracy for differentiating horses with or without musculoskeletal pain.

“It’s important to recognize that we’re not just talking about lameness when we’re talking about musculoskeletal pain; we’re also talking about gait dysfunction. And gait dysfunction can include canter. So, a horse may be able to trot very comfortably with a very low ridden horse pain ethogram score. But in the canter we see a different picture,” she said. “But when we resolve the pain, the horse is transformed both in its way of going, the quality of the gaits and in its behaviors.”

Sometimes, a more skilled rider can compensate for the horse’s shortcomings, she said, which helps the horse hide its problems longer. To investigate the influence of skill, they conducted a study examining 40 horses, each ridden by the normal rider and a single professional rider. These were horses in regular work, assumed by their riders to be working comfortably. In addition to applying an RHpE score, researchers independently evaluated gait quality, and riders were assigned a skill score by an instructor.

“Overall, the study showed that the better rider could improve the quality of the paces, but [horses] could not conceal the behavioral signs of discomfort with the professional rider,” she said.

The RHpE behaviors may have changed, but the median scores for both riders were similar.

Sometimes, it’s not just the horse
Sometimes the issue is not just with the horse, according to Dr. Dyson. “There are other factors that could influence the Ridden Horse Pain Ethogram score,” she said, which include rider morphology and weight distribution; tack fit, such as tight tree points of the saddle; and other pain related to conditions like gastric ulceration,” she said.

“I think that the Ridden Horse Pain Ethogram is a really good way of differentiating between a training-related problem and one that is related to underlying musculoskeletal discomfort,” Dr. Dyson said.

“I think when a horse is learning a new movement, it may show more behaviors than it did previously, but the score should not reach the threshold of 8, and over the next several weeks, as the horse learns what is being asked of it and is learning how to use its muscles accordingly, there should be progressive improvement, and the score should go back to baseline.

“If the scores are going progressively upward, that would indicate that the horse had a previous underlying subclinical problem, but this new movement is bringing that subclinical problem to light.”

The RHpE could also be useful when evaluating a horse during a pre-purchase examination, the effect of nerve blocks, as well as monitoring the response to treatment, she added.

“We need to be looking at the training program, the saddle fit for both the horse and the rider and the rider’s position, balance and stability. If we recognize these factors and intervene appropriately, we will improve trainability and performance.

“We are going to favor longevity for a sports horse. We are going to improve rider comfort and safety and their confidence, and it’s going to promote a harmonious relationship, which has to be what we’re ultimately trying to achieve,” she said.
Dr. Dyson is working with a company to develop an AI-based method for assessing the RHpE, which might make it easier for people to use the ethogram.

“I think when you start to recognize these behaviors, it will change your view of horses. And once you’ve seen it, you cannot unsee it. We should be striving for harmony,” she said. MeV