horse stress

If you’ve ever gotten the feeling your horse is stressed at a competition venue, you’re probably right. While previous study results have suggested horses don’t get stressed by the competition itself, a recent study indicates that they tend to become stressed in the novel environment. New barn, new stall, new neighbors, new people, new sounds and smells—all far away from home—could be the reason horses’ stress parameters rise during off-site competitions.

But, for better or worse, stress levels don’t seem to be associated with competition results—at least not in this Danish study. Salivary cortisol (the ”stress hormone”) concentrations weren’t associated with scores in dressage and show jumping horses during three national events in Denmark, said Rikke Munk, PhD candidate in the Aarhus University Department of Animal Science, in Tjele, Denmark. Munk carried out her study under the guidance of Janne Winther Christensen, PhD, also of Aarhus University.

In their study, Munk, Christensen, and colleagues collected saliva samples from 126 dressage horses and show jumpers before they left home for one of three events (two national stallion shows and one national young horse championship). They took more samples throughout the day while the horses stayed at the event. The sample collection timing was not always identical every day due to practical reasons, but the researchers made efforts to respect important factors such as before and after meals and/or exercise.

They confirmed, as previous studies have, that horses have a diurnal cortisol level—a natural pattern of high and low physiological stress responses throughout the day.

The researchers found that their study horses maintained a diurnal pattern even while at competitions. This is potentially a positive finding, she said, as a disrupted diurnal pattern could be a sign of too much stress.

“It is possible that the preservation of the diurnal rhythm when exposed to environmental disturbances, etc., can be used as information about to which degree the horse find the disturbance stressful,” she said.

They also found—somewhat surprisingly, she said—that the stress levels didn’t seem associated with competitive results. “According to the Yerkes-Dodson Law, an inverted U-shape relationship may be expected with regard to stress and performance,” Christensen said. “In other words, a certain level of arousal can be beneficial for performance but above this level, arousal becomes detrimental for performance.”

While their current study did not prove this, forthcoming research might shed more light on this phenomenon in their study, Munk said. “We should always treat nonsignificant findings with care,” she said.

One thing the study did show, however, was that dressage horses tended to be more stressed than show jumpers, at a baseline level. So just standing in the stall at the competition venue seems more stressful to dressage horses, on average, than show jumping horses.

“I think it’s a reflection of the way we manage dressage horses,” Munk said. “Usually we remove disturbing elements from their environment rather than habituate the horses to different disturbing elements. It is also likely that some temperamental traits are linked to the type of horse that we select for in relation to gaits and sensitivity to the rider.”

Christensen agreed. “Previous research has suggested that we may have selected for fearfulness in dressage horses,” she said. “The selection for extraordinary gaits/tense gaits is likely linked to fearfulness. I think there has been a tendency for highly tense horses to receive higher scores in dressage competitions. The judges—and to a certain degree the audience—decide what the ‘best’ dressage horse is.”

But that might not be the best decision, she added. “If a horse (or a human for that matter) is frequently or chronically stressed, there is a negative impact on cognitive function, health, and reproduction,” she said. “So, in my opinion, an easily stressed horse is not a good dressage horse, and relaxation should be benchmarked in competitions.”

To keep your show horses less stressed at competitions, the researchers made a few suggestions based on their studies and observations.

“It is likely beneficial to prepare young horses for the competition environment by giving them some pleasant experiences with various novel environments,” said Christensen. “I think some stress is unavoidable when horses take part in competitions, so the most important part is to allow them a good horse life in their home environment, meaning daily pasture time with other horses, sufficient roughage, and appropriate training using learning theory. This will reduce the negative effects of competition stress.”

The study, “An exploratory study of competition scores and salivary cortisol concentrations in Warmblood horses,” was published in Domestic Animal Endocrinology.