The subjects, mostly Quarter Horse geldings averaging about 14 years old, appeared calm before, during, and after riding sessions throughout the study, said Monique Hovey, MS, a graduate research assistant at Purdue University, in West Lafayette, Indiana, and formerly a student researcher at Murray State University, in Kentucky, where she and co-authors conducted the study.

“We suspected the horses might be stressed from getting mixed signals from riders who are less experienced or who have a disability which impairs their ability to ride fluidly, but we didn’t see that in our study,” Hovey said. “So that was really positive.”

A Positive Accidental Finding While Validating an Ethogram

In a pilot study Murray State researchers had validated what Hovey described as an easy-to-use ethogram so riders and coaches could identify behavioral signs of stress in horses. To their surprise, however, she said this new study showed that the horses appeared much calmer than expected.

Hovey and her fellow researchers asked two trained observers to complete the ethogram—which was developed in 2017 by blending other ethograms designed by scientists for horses and simplifying the language—while watching each horse being tacked up, ridden, and untacked during multiple sessions over several months. The study included 17 horses used in a therapeutic riding program about an hour away in Paducah, Kentucky, and 25 horses used in a beginner riding lesson program at Murray State. Observations continued for each TR horse throughout two eight-week programs and for each university horse throughout an academic semester. The observers watched the horses’ sessions live and then again by video, to assess the accuracy of live scoring.

Low Cortisol Levels and Behavioral Stress Scores

The scientists also took blood samples from the horses just before, just after, and 30 minutes after each riding session. They found cortisol (a stress-related hormone) levels stayed low—and in fact lowered slightly during riding sessions—throughout the length of the entire program. Meanwhile, ethogram scores were also low, suggesting the horses experienced little stress.

The information they gathered revealed that even when working with unbalanced, beginner students, and riders with muscle spasticity or exuberant movement and surrounded by side walkers (people who walk next to the horses to assist riders with disabilities), horses can be quite comfortable in their roles and appear calm.

Specifically with the riders with disabilities, said Hovey, “we were reassured by the fact that, just like in other studies before ours, we weren’t seeing that those horses were any more stressed in their jobs, even given the amount of people they sometimes had around them.”

Herd Management and Low Workload as Possible Factors

The horses’ general management might contribute to their calmness, Hovey said. All the horses lived in groups outdoors and had access to free-choice hay. Their breed might also have an effect, with Quarter Horses and other stock breeds possibly coping well with stressful situations—although more research is necessary to confirm that theory, she added.

The low ethogram scores and cortisol levels might also reflect the low-intensity work of the riding sessions, she explained. The horses worked for about an hour three to five times a week, mostly at a walk and trot. “It’s possible that if these horses were being pushed a little harder at a higher level, our results might have been different,” she said.

In  ongoing research the team hopes to investigate the potential relationship between cortisol levels, behavior, and muscle soreness, Hovey said.