Earlier this summer, US Equestrian added a rule allowing the Federation to begin collecting hair samples as part of its drug testing program. While blood and urine sampling have been part of USEF sanctioned horse shows for many years, hair testing is new and competitors have a lot of questions about it.  

First, it’s important to understand how testing for drugs in hair differs from testing blood or urine. When a horse is given a substance (orally or via injection), the substance goes into the horse’s bloodstream and is metabolized by the liver into active and inactive ingredients, and is also filtered through the kidneys. As it is broken down and used by the horse’s body, the substance can be found in the horse’s blood and/or urine until it is completely metabolized, usually in a period of hours, days, or weeks. Different drugs are broken down at different rates, and some may linger longer in blood or urine, depending upon the chemical makeup of the drug.  

At the testing lab, blood and urine samples are processed to see if they contain any unidentified chemical contents. The chemical mass of any unknown contents is determined, and that’s matched to a catalogue of known drugs (both therapeutic and banned substances) and the pieces they break into during metabolism (which are called metabolites). The lab must undertake further confirmatory testing to make sure the substance is a match to a regulated or banned drug before it can call a positive. 

Modern testing allows one blood or urine sample to be compared with hundreds of drugs at once and allows the lab to add new substances to its catalogue as needed.  

“The horse racing industry has been testing blood, urine, and hair for many years now,” said Dr. Stephen Schumacher, Chief Veterinary Officer and Chief Administrator for the US Equestrian Drugs and Medication Program. “As regulators in that sport have found, each medium has its strength.” 

Hair testing yields a longer-term, if less specific result than blood or urine. As a drug moves through a horse’s body, the horse’s bloodstream will bring the drug into contact with hair at the roots. Some drugs (based on their chemical makeup) will be attracted to the melanin that is part of the hair and bind to it. This creates a tiny band of the drug inside the hair shaft, which moves farther away from the horse’s skin as the hair grows out. The drug sits inside the hair, not outside, which means it can’t be washed out. (This also means that shampoos, sprays, or other environmental exposures can’t taint the hair, because they’re only coming into contact with the outside of the hair strand.) 

Testers will pull or cut a small amount of hair from a mane or tail (ideally the mane, in a small section no wider than a pencil), and it’s analyzed in a lab to look for any bands of a prohibited drug.  

The advantage to hair testing is that it can reveal drug administration much longer-term than blood or urine – often months after a horse is exposed to a drug. It doesn’t give testers as much data about the concentration of the drug that was in a horse’s system. That’s why hair will be used to find banned substances – those that should never be in a living horse at all. 

“This is just another tool in our toolbox,” said Schumacher. “Horses will be selected for hair testing in a number of ways – testing may be random, performance-based, or intelligence-based if we get a tip.”  

(Learn how to report unethical treatment of a horse at a US Equestrian competition here.) 

US Equestrian recently became aware of rumors that some participants may be giving horses barbiturates in an effort to make them appear calmer in the show ring – including the euthanasia drug, which contains pentobarbital. The Federation has a complete list of prohibited substances in hair samples available here. The list includes pentobarbital, which is in euthanasia solution, as well as phenobarbital, which is commonly used therapeutically in other species to control seizures. The latter has very rare, off-label therapeutic uses in horses, but should not be used in a horse who is in active competition because that horse would be a safety risk to their rider. 

Hair testing has been in use for decades in animals, and has been broadly deployed in the horse racing industry to check for banned beta-2 agonists such as clenbuterol and albuterol. It will not be used to look for therapeutic substances, largely because its results aren’t specific enough for it to be useful for that purpose.  

The detection of a prohibited substance in a hair test would constitute a Category IV finding, which carries a suggested suspension of one year and fine of $12,000 for a first offense. USEF provides recommended penalty ranges to hearing committee, but the committee has the ultimate discretion on penalties on a case-by-case basis. 

“If hair testing does result in a barbiturate positive, we will launch a complete investigation into the horse’s history, as well as the possible source of the substance they were exposed to,” said Schumacher.  “We are here to protect horses. Our goal with this testing is to catch the use of substances that endanger them and take action against anyone who would risk their lives (and those of their riders) in the ring.” 

Find a list of frequently asked questions about hair testing here.