The FEI has two classifications for prohibited substances; they are either banned, or they are a controlled medication. Keep reading to find out more.

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By: Dr. Shannon Pratt-Phillips, PhD |

Banned vs. Controlled

The FEI Clean-Sport division regulates the anti-doping program for all equine athletes in FEI-sanctioned events, as does Equine Canada and other governing bodies for different types of shows and competitions. The FEI has two classifications for prohibited substances; they are either BANNED, where the substance has no place in equine sport (such as cocaine or lithium), or they are a CONTROLLED MEDICATION (such as thyroid hormone or furosemide), where substances may be used as therapeutic agents, but are not allowed in competition. These substances or their metabolites may be allowable in certain concentrations in blood, tissue, or urine. Many of these medications need to be pre-registered for their use prior to competition. A full list of FEI’s prohibited substances is available at

The prohibited substances may further be classified as legal medications used inappropriately, such as in too high a dose or too close to an event; performance-enhancing drugs (which are banned); naturally-occurring prohibited substances (NOPS) in feeds (such as morphine from poppy seeds); or accidental contaminants in feeds.

What’s Really in the Ration?

With respect to the latter two categories, feed companies – and those feeding the horses – need to be aware of what goes into the feeds, and ultimately the horses. This includes being critical of any products that may claim to be “natural,” as many prohibited substances are in fact natural, such as caffeine or opium. Herbal supplements are often poorly regulated and may cause problems. In fact, the FEI has taken a stand regarding herbal or natural substances: “The use of any herbal or natural product to affect the performance of a horse or pony in a calming (tranquillizing) or an energizing (stimulant) manner is expressly forbidden by the FEI regulations.”

Furthermore, commercial feed manufacturers may claim their products do not result in positive tests, but they are not actually screened by the FEI and therefore owners and riders are at risk of being misled. Even horse owners mixing their own rations should be aware of the sources of their ingredients.

Ultimately, it is the responsibility of those involved with the horses to be vigilant about the products and feeds they offer their mounts. However, we all know mistakes happen. It is not uncommon for horses under the strictest of care to test positive due to something inadvertently fed, such as a contaminant or additive in their ration. In fact, there are many compounds that may accidently contaminate horse feeds.

The Common Culprits

Poppy seeds. The seed pod that houses poppy seeds contains opium and morphine, which can coat or otherwise be transferred to the seeds during harvesting. Oats and other grains may be contaminated by rogue seeds from poppy plants. Because opiates are banned substances, there is no allowable threshold, so a horse accidently consuming poppy seeds in its oats would be disqualified if tested.

Hordenine is an alkaloid found in sprouted barley, and is closely related to epinephrine. Products including brewer’s grains or distiller’s grains may contain hordenine.

Atropine is found in nightshade plants and jimsonweed, and therefore may contaminate pastures or other feeds.

Caffeine and derivatives such as theobromine (found in chocolate) and theophylline (found in tea) may be found in horses that have consumed feeds containing bakery waste. While rare in equine feeds, it is fairly common in other livestock feeds and could be ingested by a horse via cross-contamination or accidental feeding. Products that have been shipped with cocoa or coffee beans have reportedly contaminated horse feeds.

Salicylic acid (aspirin) is found naturally in many plants, including alfalfa and willow bark. It is also used topically for various ailments. There is a maximum threshold for salicylic acid to allow for naturally-occurring levels, but that may be easily overshot if a horse is exposed to excess amounts accidentally.

Ractopine is found in swine feeds, and if a feed manufacturer does not properly flush out the mixing equipment between batches, there is risk of cross-contamination.

Isoxuprine, which is commonly used for the treatment of navicular disease, has the ability to stick to feed storage tubs, feed tubs, and even bedding, potentially resulting in contamination of horses not on the medication.

Some liniments or other topical compounds can be absorbed through the skin. For example, oil of wintergreen or other cool-down types of products contain methyl salicylate, which is a controlled substance.

There are also reports of people using recreational drugs and handling horses, thereby resulting in some cross-contamination and subsequent positive tests.

Minimizing the Risk

Because of the exhaustive list of additional health risks due to accidental contamination of feeds, those who care for horses should be particularly vigilant. There are three areas in which contamination risk can be minimized:

1.) Stable management – includes limiting access of visitors to the horses; washing hands afterward or wearing gloves when administering medications; avoiding the sharing of stalls, tack and equipment between horses; and cleaning stalls and trailers well after use and between horses. It also includes avoiding eating or drinking substances (particularly coffee and chocolate) in the horse facility to avoid any spilling and contamination.

2.) Medication management includes knowing the rules about the drugs being used, including withdrawal times; taking care to ensure powdered medications are not carried by the wind; avoiding compounded medications where possible (recall the selenium toxicity that resulted in the deaths of numerous polo horses in Florida); and keeping excellent records at your farm and with your veterinarian.

3.) Feed management – some feed companies, particularly in Europe, may provide the NOPS designation that ensures their feeds have been produced under strict quality assurance to avoid these naturally-occurring prohibited substances. If these approved feeds are not available locally, managers can still aim to buy their commercial horse feeds from companies that have excellent quality control standards. These companies ensure that their raw ingredients, mixing equipment and packaging processes are tightly controlled to avoid contamination or mixing errors.

A stable manager should be able to obtain a full list of ingredients and sources/producers of a feed’s ingredients upon request – and if they don’t, then they should consider using a different company. This holds true for hay dealers; managers should only purchase hay from reputable dealers with known sources of their feed. Owners should also monitor their pastures for weeds or grasses that might contain compounds on the prohibited substance list.

Proper Storage

The feed itself should be stored in a safe and dry space, ideally on pallets above the ground in a locked room to minimize contact with vermin and potentially unlawful humans (not to mention an escapee horse!). Feed produced for other species such as livestock or pets should not be stored in the same area as horse feeds.

Similarly, when mixing feeds and supplements for different horses, managers should always use the same bucket for each horse. When multiple supplements are used, extra care should be taken to ensure a horse doesn’t accidently get double dosed.

A practice that is becoming more routine is collecting small samples from every batch of hay, bag of grain, and/or supplement, and dating and storing them safely in a cool place. That way, if a problem ever were to arise, the horse’s managers can go back to these samples for testing to try to determine the source of a contamination.

Future Concerns

It should also be noted that several nutrients administered to horses prior to competition that are not currently scrutinized may be controlled or banned be in the future. For example, magnesium sulfate (injected) is a controlled substance, but is commonly fed orally in levels well over the National Research Council’s “Nutrient Requirements of Horses” suggested requirements. Similarly, some horses are given injectable mixes of B-vitamins prior to competition, and while these are recorded by the administering veterinarian, their effects on performance are not known. Should any of these compounds prove to provide sedating (such as in the case of magnesium) or performance-enhancing effects (B-vitamins), it is possible that they would be added to the list of prohibited substances to ensure safe and fair competition.

Electrolyte administration is also a common practice, as is the supplementation of amino acids, although it is unlikely these would ever be scrutinized. This holds true for joint therapies such as oral joint supplements containing chondroitin and/or glucosamine, or injectable versions (into the muscle, blood, or joint) that are currently allowed.

Even the most well-meaning rider is at risk for exposure to feed contamination or accidental mixing or handling of medications or supplements. While many riders feel the policing and testing of horses (and riders) is perhaps an overzealous effort of the FEI, these compounds are banned or limited to ensure competitions are fair and that horses are not put at risk. We should hope that all of those in the equine world would want the same thing.