French behavior researchers have reported that horses participating in equine-assisted intervention (EAI) programs seem to have significantly increased sensitivity to skin contact compared to conventional riding school horses. This, they said, could be because the horses get touched more than they want, in places they don’t want, or in ways they don’t particularly like. EAI programs encompass a range of activities involving horses that can be used to promote human physical and mental health.

In their study the scientists found that therapy horses had the greatest increase in skin sensitivity in areas commonly brushed by people with mental and developmental disabilities. Their findings suggest EAI horses might experience better welfare if therapists guide patients to groom horses and ponies differently, or if their sessions include less touching, said Martine Hausberger, PhD, researcher at the Laboratory of Animal and Human Ethology (the science of animal behavior), a branch of the French national research center and the University of Rennes.

“We tend to assume that horses like physical contact, but, as previous studies have shown, we’ve noticed that doesn’t always seem to be true,” she said. “But in therapy sessions, there’s a lot of physical contact between the patient and the horse.”

Hausberger noted that touch is often the main activity therapists encourage during equine-assisted interventions, said, though many of the participants might prefer mere visual contact. “It’s like it’s therapy that has this obligatory aspect of touch even when neither participant actually wants all that tactile contact,” she said.

Scoring Tactile Reactivity in Riding School and EAI Horses

Horses, including ponies, are among the most utilized species in animal-assisted activities for people with disabilities, such as those with autism spectrum disorders, Hausberger said. Sessions usually include a significant amount of physical touch between the patient and horse, such as grooming and stroking.

Hausberger and her fellow researchers noticed equine-assisted activity horses and ponies tended to show less interest in humans and sometimes even more avoidance than horses used in riding lessons for people without disabilities.

To investigate, they tested 32 mares and 28 geldings living in one of two riding centers in France. Six of the animals worked exclusively in equine-assisted programs, and 14 worked only as riding school mounts. The rest divided their time between activities at varying percentages.

The researchers tested the horses’ tactile sensitivities by looking for any tremors or skin twitching in response to being touched by four sizes of von Frey filaments—small, flexible hard plastic sticks with nylon threads branching off—on the chest, the base of the withers, and the stifle on both sides. The researchers divided 24 tests into two sessions 30 minutes apart for each horse in a random order. Horses received one point for each tremor, for a maximum of 24 points in the tactile sensitivity score.

Scores ranged from 0 to 24, with a very high variation between individual horses. The highest scores, however, consistently occurred in the EAI horses, Hausberger said.

In particular, the EAI horses were more than twice as reactive to the thinner filaments than riding school horses were, pointing to a greater tactile sensitivity, she explained. And while all the horses were more sensitive at the stifle than elsewhere on the body, that was especially true for the EAI horses.

Interestingly, it was only the full-time EAI horses that showed such a strong difference in tactile sensitivity, Hausberger added. The horses performing mixed work varied little in their tactile sensitivity compared to exclusively riding school horses.

By contrast, the riding horses showed higher tactile sensitivity at the withers than therapy horses did, she added.

Otherwise, the researchers found no real differences in horses’ reactions between one side of the body and the other, nor between the two riding centers, Hausberger said. Tactile reactivity also wasn’t affected by age, sex, or type of equid (horse vs. pony) did not affect reactivity.

People With Disabilities Brush the Hindquarters More

To try to understand more about this increased tactile sensitivity in EAI horses, Hausberger and her team then asked 17 people diagnosed with mental or developmental disabilities and 29 people without diagnosed disorders to groom a horse. Specifically, they instructed 46 people—aged 18 to 45—to brush one of 29 horses with a soft brush for one minute on each side, however they wanted.

The horses in this study included nine working exclusively as EAI horses, nine working exclusively as riding school horses, and 11 privately owned leisure horses, living on five separate farms in France.

Analyses of video footage revealed that the people with diagnosed mental/developmental disabilities spent more time brushing the hindquarters, whereas people without disabilities focused on the front of the horse, she said. The people with disabilities also showed more “fragmented” actions—picking up the brush, brushing, stopping, then brushing again—compared to those without.

Are Therapy Horses Getting Too Much Unwanted Contact?

The findings suggest therapy horses might become more reactive to touch because of the way they’re groomed and handled, Hausberger said.

That might seem surprising, because it’s often assumed therapy horses are more tolerant of human contact than riding school horses, she explained. “We almost expected them to respond less to tactile stimulation, either because they had become habituated, or because they had been selected by the therapy organization’s managers as being less reactive.”

Horses might also serve as useful therapy animals without being touched, or with very little touch. “We just have this fixed idea that interactions with animals should always involve touching,” Hausberger said. “But maybe it’s worth considering other approaches, like watching horses from a distance, or interacting with them in ways that don’t involve so much touching.”

Take-Home Message

To improve the welfare of therapy horses, handlers and therapists might need to reconsider the way horses are touched, said Hausberger. They should carefully watch how each horse responds to physical contact during therapy sessions.

“Always observe the horse and his reactions, and maybe better manage the way the touch is carried out,” she said. “The fact that the hindquarters seem to be the privileged zone for people with disabilities may be causing a problem for the animal, so it’s important to observe and to guide participants to touch horses more favorably.”

The study, “Horses’ Tactile Reactivity Differs According to the Type of Work: The Example of Equine-Assisted Intervention” appeared in Veterinary Sciences, in February 2023.