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June 2019 - Lower Respiratory Diseases in the Horse

Respiratory conditions in the horse are never anything to sneeze about, especially when it comes to equine influenza, herpesvirus, asthma or even "heaves." Pose your questions for this month's expert, Dr. Lynn Martin, related to respiratory diseases in the horse.



Click here to read this month's questions and answers.

Drug Testing in the Horse


  1. What is the current status of testing for hemp based products? Are terpene levels monitored? (View Answer)

    Drug testing is not yet focused on testing for terpenes,  as they are a component of many fragrant plants, lininents and hoof conditioners.   However, both cannabidiol (CBD) and tetrahydrocannabinol (THC) are identified in horse urine and are considered to be violations in horse racing.  THC is a 1A violation and CBD is a 2B violation, regardless of the level found.  In humans, a 15 ng/ml urinary cutoff is in place for THC to prevent positive tests from inadvertent environmental exposure.  There is no human sport in which CBD is considered an illegal substance. 

     

    Hemp products comprise a wide spectrum of different feed additives, so it is important for you to know what plant component you are feeding. The Federal government requires that hemp contain less than 0.3% THC, which is well below the 5 to 10% typically found in Marijuana, but sufficient to cause a positive test. Most hemp products, including hemp hearts, hulls and meal are well below 0.3% for THC. Hemp seed oil usually contains very little, if any, of either CBD or THC, as it is simply the oil from the seeds, and the CBD and THC are in the leafy parts of the plant, particularly the flowers. Full spectrum hemp oil is oil pressed from all of the plant parts left over after the fibrous stalks are harvested for textile use. This product contains the terpenes, CBD, other cannabinoids and whatever minimal THC is in the plant. You can differentiate full spectrum hemp oil from hemp seed oil by the color. Hemp seed oil looks clear and yellow, similar to other vegetable oil products, and full spectrum hemp oil is green.

     

    Another confusion about hemp products are those labeled as CBD oil. These products are typically olive or soy oil with purified CBD added. While many of these products are still readily available, the FDA has clearly made their position known, that CBD oil available in this way is a prescription drug. You will gradually see the availability of products labeled with CBD become prescription only.

     

    In conclusion, you need not be concerned about the terpenes in hemp products, but, until screening cutoffs for CBD and THC are developed for horses in competition, you should steer clear of these products if your horse is subject to drug testing. Clara Fenger, DVM, PhD, DACVIM, Georgetown, KY

  2. What is the time period one must wait before competing at a USEF/USDF competition after giving one gram of Bute orally? I have been told by some riders that as long as they have not had more than one gram, it can be given up to right before competing. Is this correct? (View Answer)

    One can always administer a medication closer to the event if one reduces the dose. That said, one gram given orally right before competing could well pass the test but I would absolutely not recommend it due to the following:

     

    1. The absorption of the medication and the time to produce an effect means that there is little possibility of a pharmacological effect at the time of competition.

     

    2. One is by definition not in compliance with the medication rules one is competing under.

     

    3. Depending on when the horse last had been administered Bute or another NSAID, you are potentially risking a violation with no benefit. Thomas Tobin, MVB, MSc, Ph.D., MRCVS, DABT, The Maxwell H. Gluck Equine Research Center, Lexington, KY