Could Aromatherapy Help Calm Stressed Horses?

Many people employ aromatherapy as a natural stress reliever, but could the same approach be used to calm stressed or nervous horses? According to study results from one research team, aromatherapy might have a place in the barn, after all.

Clarence E. Ferguson, PhD, an associate professor in the Department of Agricultural Sciences at McNeese State University, in Lake Charles, La., and colleagues recently tested lavender aromatherapy's efficacy at decreasing horses' heart and respiratory rates after a stressful experience.

Ferguson’s team recorded seven mature Quarter Horses' heart and respiration rates while the animals were at rest in their stalls. They assigned each horse a "calm score," which ranged from 1 to 5 (1 being very calm and 5 being very excited) and was based on "the level of calmness observed as several people walked in and out of the stall." The researchers separated the horses into two groups; one group acted as a treatment group and the other as controls. After about one week, the researchers subjected the groups to the opposite treatment.

Researchers placed horses in both groups in individual stalls before sounding an air horn adjacent to the stall twice. Following that stressful experience, the team measured horses' heart and respiration rates (stressed rates) for one minute.

Next, the team exposed horses to humidified air for 15 minutes—the treatment horses received air produced from a mixture of water and lavender essential oil while the control horses only received water—before remeasuring the horses' heart and respiration rates (recovery rates).

The team found no significant difference between the resting heart rates in either group, no significant difference in the change in the groups' collective heart rates between resting and stressed, and no difference in respiration rates between the groups at any point in the study.

There was, however, a significant difference in recovery heart rates between the two groups: Horses that breathed humidified air with the lavender scent had significantly lower recovery heart rate than control horses. The team also found that the lavender scent significantly reduced the heart rates of the three horses who received a calm score of 2 (the remaining horses had a calm score of 1) after the stressful experience, compared to when those horses served as controls.

Although this study showed that 15 minutes of aromatherapy using lavender essential oil is effective in reducing heart rates after a stressful experience, Ferguson noted some limitations with the study.

First, he said, a greater sedative effect noted in horses with a higher calm score might be due to the fact that these horses' heart rates increased more after the stressful experience. This, Ferguson said, would allow for a greater heart rate difference between the control and treatment horses.

He also noted that reports from human literature suggest that lavender aromatherapy is more effective when used as a short-term stress reliever than when used long-term.

"Additionally, one limitation of this study is that the horses used were American rodeo horses, which do not easily become stressed because of an airhorn," Ferguson said. "These horses are accustomed to explosions during rodeo opening ceremonies. In future experiments, the use of feral horses, yearlings, or foals may demonstrate greater changes after lavender aromatherapy."

Still, Ferguson believes lavender aromatherapy can be useful for helping reduce stress in horses.

"Equine practitioners could use lavender aromatherapy to reduce nervousness among horses in the examination area, or for treatment following performance competition to possibly hasten recovery time," he said.

The study, "Effect of Lavender Aromatherapy on Acute-Stressed Horses," appeared in January in the Journal of Equine Veterinary Science

Disclaimer: Seek the advice of a qualified veterinarian before proceeding with any diagnosis, treatment, or therapy.