Cannabis Use in Horses

Perceived by some as a controversial treatment, cannabidiol, or CBD, is on the rise in equine health products.

It’s hard not to notice the recent buzz around CBD. This ingredient is included in many new products for humans, horses and pets, along with label claims that CBD relieves pain, stress and anxiety and can effectively treat multiple problems. For humans, it is commonly sold as a liquid placed under the tongue. It also comes in oils, pills, and topical creams and can be included in food.

What is Cannabidiol?

Most CBD products are made from hemp, which is a type of cannabis. There are multiple species of cannabis, a family of plants originating in Asia, and several strains within those species. Hemp includes varieties cultivated for production of fiber, seeds for food, and oils. Other types of cannabis, chiefly marijuana, are used for medicinal purposes in humans and as a recreational drug.

Cannabis plants have more than 100 chemicals called phytocannabinoids—the prefix “phyto” means plant. The two chemicals of interest are cannabidiol and tetrahydrocannabinol, or THC. Some strains are bred to produce minimal levels of THC, the main psychotropic constituent of cannabis. Marijuana’s THC content is usually 10 percent or more—and some marijuana strains today contain much more THC than they did several decades ago—but hemp must have a THC content of 0.3 percent or less, according to federal law. At this low level it has no intoxicating effect, for people or animals.

Legalization of Hemp

Humans have been using cannabis for various purposes for many years, but because of the mind-altering effects of THC, all forms of cannabis have been illegal in the U.S. until recently. With the 2018 Farm Bill, industrial hemp (THC content 0.3 percent or less) is no longer considered a banned or controlled substance. It is now a farm commodity, although THC remains a Schedule 1 drug with the Drug Enforcement Agency.

With this change in status, hemp is now utilized for many purposes besides the traditional fiber for ropes, baling twine, clothing, paper and more. Extraction of CBD for humans and animals is now legal in all states except Idaho, Nebraska and South Dakota. In states where marijuana has been legalized for medicinal and recreational use, CBD products can also be made from marijuana, but those products might contain more than the legal limit of THC and cannot be shipped across state lines.

Pet owners and horsemen are using multiple products in a fast-growing market—for pain relief, calming, anti-anxiety, and various medical conditions in their animals. Efficacy and safety of some products is questionable, however, because there’s been very little research. Until the passage of the 2018 Farm Act, it was illegal to possess or conduct research on hemp as well as marijuana. Because the Food and Drug Administration does not yet regulate CBD products, you can’t always depend on label claims. According to a study published in the Journal of the American Medical Association, nearly 70 percent of CBD products sold online do not contain the amount of CBD stated on the label. At this point it is still “buyer beware,” and consumers must do their homework before selecting CBD products.

Even though there are many benefits for horses with certain products, horsemen need to be aware that CBD as well as THC cannot be used in certain disciplines when competing, and if CBD shows up on a drug test that horse may be disqualified.

Buyer Beware

It’s important to realize that hemp can be more than 0.3 percent THC, especially when certain ingredients are extracted. “If you start with a plant that has 0.1 percent THC and extract a certain part of that plant, the amount of THC might be 10-fold higher in the extracted portion because the extract is more concentrated,” Chelsea Luedke, DVM, MS said.

“Then you are at 1 percent THC, which is illegal.” People buying any cannabis products should exercise caution. “Make sure the company creating the product has certificates of analysis to show what is actually in it. There are at least 15 different tests for things you’d potentially look for, including potency,” Luedke said. “This would address the cannabinoid profile, making sure there are not high levels of THC. If you had even 0.2 percent THC in a hemp product and were giving a lot of it to a horse, it would show up on a drug test.” In many disciplines, both CBD and THC are banned for use when showing. At this point there are still gaps in knowledge and much misunderstanding about these products, so it is important for horse owners to do their homework.

“There are no FDA regulations,” Luedke said. “For pets, there is minimal oversight or quality control, which leaves it up to consumers to look at the companies’ COAs. If these are not posted on the company’s website, ask to see them.

Make sure the content corresponds with what’s stated on the label and that there are no contaminants.” At minimum, testing for potency, presence of residual solvents, pesticides, microbial contaminants and heavy metals is important. Hemp absorbs and amplifies whatever is in the soil. There may be pesticides or herbicides, and those contaminants will be very concentrated in areas of the plant from which cannabinoids are extracted. many people don’t know what to look out for. “Ultimately, it comes down to lab analyses and making sure they are based on that specific batch,” Luedke said. “That’s why every single label we send out has a lot number and expiration number, and those can be referenced to the CoAs we have on each batch. This is important, because some companies may only test one batch per year and batches may vary in what they contain. You don’t know where it was grown, and it’s common to have extraction labs combine large batches of plants to be more efficient.”

Plants on the same farm from year to year can vary in THC content, depending on growing conditions. The important thing is batch testing and having this information available. At this point, the market is largely buyer beware. more research must be done to address safety issues and dosing. “We haven’t seen adverse side effects with the doses we’ve been giving, and these horses are closely monitored—assessing appetite, manure production, behavior,” Luedke said. “When more numbers of horses are given a product, however, there may be chances for side effects—interactions with medications they are on, individual sensitivities, and more.”

Some individuals should not be given cannabinoids, and these include young animals and pregnant or lactating mares. “This would include any horses under a year of age, because they are still maturing their own endocannabinoid system,” Luedke said. “It’s the same for young humans—if we interfere with their immature system with either synthetic or plant-based cannabinoids, we might interrupt maturation of their own endocannabinoid system. Pregnant or lactating mares should not be given anything that has not been proven safe for the embryo, fetus or foal.”

Hemp Products for Horses

Stefanie Harrington’s Tight Joints Plus in Auburn, Washington, has been manufacturing joint supplements for more than 20 years and recently added hemp extracts for more health benefits.

“Our original product is an all-natural, anti-inflammatory pain reliever with joint support for horses and dogs. Some people use it on show cattle, show pigs, goats and other livestock. It can be used on any animal and contains 11 active ingredients and works as a total-body anti-inflammatory, but it does not contain hemp,” Harrington said. “It contains glucosamine, MSM, vitamin C, devil’s claw, yucca, hyaluronic acid, vitamin E, manganese, copper, shark cartilage and Boswellia, which is a natural pain reliever. A small amount is added daily to the horse’s grain.”

As hemp products became available, Harrington began looking at hemp seed oil and CBD products—both with different benefits. Hemp seeds themselves do not contain CBD, therefore hemp oils pressed from seeds do not contain CBD. Hemp oil, on the other hand, can be derived from stems, leaves, flowers or the whole plant, which means it could contain CBD.

Hemp seed has many benefits, including its fatty acid profile, and people have been using hemp seed and hemp seed oil for many years.

“Most of the research on hemp seed oil and CBD products is from Canada, Europe and Australia, because those countries have been using hemp products for years,” Harrington said. “The U.S. is way behind because it was illegal to do research—people still thought hemp was marijuana.”

Harrington’s first focus was on hemp seed oil because of the nutritional benefits. “It is nature’s most balanced oil, with the correct ratio of omega 3 to omega 6 fatty acids and also contains omega 9, and an essential fatty acid called GLA (gamma-Linolenic acid),” Harrington said. “GLA is actually an omega 6, and even though omega 6 fatty acids are typically inflammatory, GLA is not. It is an anti-inflammatory essential fatty acid that benefits hindgut health. It is helpful for horses that are susceptible to ulcers.” Hemp seed oil also aids the immune system because of all the antioxidants it contains. The hemp seed oil Harrington uses is cold-pressed and not heat damaged.

“We only press seeds grown in the U.S.,” Harrington said. “With hemp from other countries, you don’t know what contaminants might be in it. We third-party test everything to know exactly what’s in it, and have a certificate of analysis on every batch.”

More recently, Harrington started looking into CBD products for horses, especially since she has a horse with anxiety problems and many people give CBD as a calming agent. “Hemp oil contains other parts of the plant and not just the seeds, and usually has some CBD,” Harrington said. “I was at a horse expo where a company was giving out samples of CBD. This company was selling tiny pellets, saying you only need to give a horse one teaspoon per day. I took some home and gave them to my horse and she wouldn’t eat them. These pellets were rock hard, tasted terrible, and my mare sorted through her grain and left the pellets. When I started doing research, I found there are several large corporations that mass-produce CBD products—tinctures, pills, gummies, dog treats. When they extract the CBD, the biomass that’s left after almost all the CBD is removed is what they make into pellets. There may be only tiny amounts of CBD left in it, and no oil or seeds.”

Harrington wanted to find something horses would eat that contained consistent levels so consumers would know how much CBD they were feeding, with a certificate of analysis to prove it. “We decided to make a cookie containing hemp seed oil, hemp seed protein powder, unsweetened applesauce, vitamin C, a little water and whole wheat flour to bind it all together,” Harrington said. “Once we had a recipe that would hold together, we added CBD extract, and knew exactly how much was in it, with a third-party lab test to prove a guaranteed quantity.” Harrington adds that her goal was the nutritional benefits from hemp seed as well as the CBD.

“With the CBD we notice a mental change—it brings a better balance to horses’ minds,” Harrington said. “Most people who buy our CBD cookies are using them for horses that have anxiety issues—maybe trailering, being naughty in the warm-up arena or can’t focus on their work because they are too nervous or upset. The cookies produce a calming effect. Horses have an extremely efficient endocannabinoid system—the body creates its own cannabinoids—so you don’t need to feed very much. Our cookies contain only 25 milligrams of CBD, and we suggest starting with one cookie per day and monitoring the horse for a few days to see if you get the results you want.” Harrington says owners need to find the right balance for each horse. Some may only need one cookie per day and some just half a cookie. Each animal’s sensitivities to CBD are different.

Finding a Source

When Harrington was trying to create a product to sell, she contacted several facilities to find the material needed and discovered it can be hard to locate quality products.

“Washington is behind the times when it comes to hemp products, but Oregon has taken the lead,” Harrington said. “I met with Tonia Farman at Hemp Northwest who helped me with the recipe for the CBD cookies.” Harrington’s first production of oil— for the oil product, not CBD—was pressed from the first hemp plants ever grown for seed production in Washington state.

“All our hemp is grown and pressed in the U.S. thanks to Hemp Northwest,” Harrington said. Tonia Farman and her husband and business partner, Gregg Gnecco, started Hemp Northwest in Hood River, Oregon, in 2017. Farman was interested in healthy foods, having worked in cancer survivorship for many years. “I ran adventure therapy programs for young adults with cancer,” Farman said. “Through that experience, I witnessed poor diet and nutrition habits, high anxiety, and other post-cancer issues that traced back to inflammation. This was our motivation behind getting into hemp, which has many anti-inflammatory properties. Washington and Oregon had just opened their hemp program, and we started pressing hemp seed oil in June 2018. Then we added protein powder and hemp hearts to our products. In December we added CBD because many of our customers were asking us for CBD products.”

Farman notes that they use the entire plant minus the THC. “Hemp seed oil has a wonderful fatty acid profile, and we decided to use it as a carrier for CBD—which comes from other parts of the plant,” Farman said. “We use plants from which THC has been removed, using the entire plant mass.”

Farman recognized great benefits from hemp seed oil, despite the fact that the Association of American Feed Control Officials has not formally approved it as a feed yet. AAFCO is the association of local, state and federal agencies charged by law to regulate the sale and distribution of animal feeds and animal drug remedies.

“The Hemp Feed Coalition and AAFCO are working together on a study,” Farman said. “They started with hemp seed oil and its benefits to get it approved for animal feed. It will be a couple more years before the study is finished.” The FDA approved hemp seed in December 2018 as a human food ingredient, so it now has GRAS (Generally Recognized as Safe) status. “This means it can be included as an ingredient in any food product,” Farman said. “This was a huge step forward. The next step is to gain that status for animal feed, so that’s what AAFCO is trying to do, with help from the Hemp Feed Coalition. There is so much interest right now that we hope it will help expedite the process. We get many calls from animal nutrition companies for hemp seed oil as a nutritional supplement.” There’s also growing interest in CBD. “Today many retired veterinarians are coming forth and talking about benefits of CBD,” Farman said. “The ones still in practice are reluctant to talk about it, however.”

Now that hemp and CBD are no longer illegal controlled substances, there will be more research and more money available for research. When there are more studies and peer reviewed research, some of the stigma about hemp may change. “We get our hemp mainly from growers in the Northwest. Last year we started getting it from the Colville Tribe in Washington State,” Farman said. “We also get some from North Dakota and Minnesota. We have all of it tested. The farmer has to test for contaminants and levels of CBD and THC. It can’t have THC levels above 0.3 percent, and these plants must also be free of herbicides, pesticides, heavy metals or other contaminants.”

Research Efforts

Chelsea Luedke, DVM, MS, co-founder and chief veterinary advisor of Vet CS in Centennial, Colorado, and Trish Wilhelm CVT, VCC, started Vet CS two years ago. As an equine veterinarian, Luedke applies clinical experience to product development and manufacturing high-quality CBD hemp extracts for horses. Luedke’s company created a CBD paste for horses, which is easy to give and easy to measure.

“We came to the market with some of our products in 2018 to create a reliable solution for pet and horse owners,” Luedke said. “We’d seen a lack of scientific evidence in many products offered and questionable health benefit claims. We wanted to try to address some of those problems with clarifications on dosing and transparency regarding where ingredients come from.”

According to Luedke, many horse and pet owners were trying to adapt human products—either medical marijuana or hemp they’d grown themselves to make homemade batches—for their animals. In dogs, some people were using human CBD oils that contain the sweetener xylitol, which is toxic for dogs. Luedke is an equine veterinarian specializing in sports medicine and lameness and had many clients willing to be part of her study. The horses were given different doses, with different lengths of time in between, and different preparations.

“We started with a plain isolate in oil formulation and then did blood work on those horses using a lab at Colorado State University to determine blood levels reached,” Luedke said. “This took time, but we wanted to go about this scientifically to see if the horses’ flexion scores improved compared to their baseline before starting the cannabis therapy. We were very encouraged by the response. One horse had multi-limb osteoarthritis and had not responded to traditional therapies. I generally do not reach for CBD as a first therapy. There are many well-established and effective medications, and I reach for those first. Horses in our study were some that failed to respond to traditional medicine, and we were looking for something else to try.” One horse had severe osteoarthritis in a hind limb, and pain was significant enough that he was lying down all day and not eating well. The next option was humane euthanasia.

“He was on 4 grams of Bute daily, along with gabapentin,” Luedke said. “He’d also had shockwave therapy and other local therapies—we’d run out of things to try. We gave him a high dose of 5 milligrams per kilogram of body weight of CBD. Within 24 hours the owner reported that the horse was standing up and moving, even running around in his pen. He also started eating better. We did five daily doses on that horse, then 24 hours after the last dose he started becoming lame again. We tried different doses until we found the lowest level that would still give relief. Every horse is different, and with cannabinoids and CBD therapy in particular, you need to adjust dosage to the individual horse.” Some horses are extremely sensitive to CBD and only need a small dose to get the beneficial effect.

“CBD is very safe, but we don’t want to unnecessarily give high doses, because that would be expensive,” Luedke said. “It’s important to determine the effective dose for each horse. Some horses are very sensitive and only need 60 to 70 milligrams per day, as opposed to the horse with severe arthritis pain that got 2,500 milligrams.” Luedke asserts that much more research needs to be done.

“We are currently doing a pharmacokinetic study, using a lab at Colorado State University, on eight horses,” Luedke said. “We give them a certain dose and check blood level at six different time points in the first 24 hours. This will tell us how long it lasts in the blood plasma. It will give us the half-life and how many days before it’s out of the horse’s system, and more insight into why different horses are affected differently. This is a small study, but a stepping stone to more research on efficacy and how to use CBD.” Another indication in horses that Luedke wants to study is laminitis.

“We’ve had good success treating laminitic horses with CBD for pain modulation,” Luedke said. “Some cases have not responded to traditional therapies, and either the coffin bone continues to rotate or sink or we can’t get the pain under control, so we’ve used CBD as an adjunct. This requires a high dose, usually 400 to 500 milligrams per day, but within 24 hours of the first dose those horses become more comfortable. If you can keep a laminitic horse comfortable during the period in which you are changing the other aspects and treating the primary problem—whether taking the horse off lush pasture, addressing the feet, or something else—you can manage the pain better using CBD. This can buy time to address what’s going on with the feet and provide a better outcome.”

In humans and pets, CBD can help for seizures, cancer and renal failure, but these are ailments not common in horses. “The main three indications in horses are anxiety, osteoarthritis and laminitis. I’ve also used hemp extract with success in horses with decreased appetite,” Luedke said. “I think we will find more applications in horses, but we’re not making a lot of claims at this point until more research is done.”

This article was originally published in the November 2019 issue of Barrel Horse News.