Using cannabidiol (CBD) to treat horses with arthritis or anxiety has gotten attention since the 2018 farm bill legalized industrial hemp, according to Tarleton State University in Texas, but the question is whether it works.

Researchers at Tarleton State's Equine Center are looking into CBD use in horses right now in a unique study that has the attention of horse owners around the world, the university said in an announcement.

“I have just been overwhelmed by the level of interest in this study,” said Dr. Kimberly Guay, who is overseeing the research. “By now, horse owners have all heard the hype about the potential benefits of CBD oil. Here at Tarleton, we are working to give them the reliable data that’s just not there yet.”

Guay’s study seeks to quantify how CBD affects inflammation, stress and stereotypical negative behaviors in horses.

Guay and her student researchers from Tarleton’s equine science classes give horses in the trial different kinds of CBD, such as oil or pellets. Then, they measure the physiological effects of the non-psychoactive substance on the horses’ heartrate and cortisol levels. They also observe the horses after dosing them with CBD to note its effect on any common obsessive compulsive behaviors common to horses that spend time in a stall or trailer, such as cribbing, which is when a horse bites on a fence or gate.

“We are also tracking how long CBD stays in the horse’s system,” Guay said. “Many people who compete with their horses are interested in using CBD products to reduce stress and inflammation, but many event organizers are still working through their CBD restrictions for horses in competition.”

While horse owners await the results, Guay said she expects to publish her data sometime in 2021.

According to the Association of American Feed Control Officials (AAFCO), CBD is not a legal ingredient in animal foods in the U.S., because as of yet, no industry company has come forward with a request for an approved definition and followed the AAFCO ingredient definition process. AAFCO added that there is also discussion about whether CBD is a "drug" or a "supplement," which would influence how CBD would be regulated. AAFCO is a voluntary membership association of local, state and federal agencies. Its members are charged by their local, state or federal laws to regulate the sale and distribution of animal feeds and animal drug remedies.