Cleanliness in the stall can equal cleanliness on the drug tests, especially when it comes to sport horses receiving therapeutic medications, according to results from a new project under development by French researchers.

Presented at the 34th Annual Equine Research Day in Paris Feb. 28, the study complements previous research showing that treated horses can contaminate other horses and/or re-contaminate themselves with the same drug even after the medication has been stopped, potentially resulting in positive results on drug tests.

Photo Courtesy Marie-Agnès Popot, PharmD, PhD

In both cases, soiled bedding appears to be a principle vehicle for contamination, said Marie-Agnès Popot, PharmD, PhD, head of research at the Laboratoire des Courses Hippiques south of Paris and author of the study. In a series of experiments, Popot’s team tested drug levels twice daily for two weeks in the urine of horses treated with a common therapeutic and of untreated horses who had shared the treated horse’s stall. Stalls were either fully cleaned daily with fresh straw, partially cleaned, or not cleaned at all. When fully cleaned, contamination rates were low, but when partially cleaned or not cleaned at all, drug levels were present in both the treated horse and the untreated horses at high enough rates to show positive on a drug test.

"The risks of auto-contamination and cross-contamination are real when dealing with certain treatments commonly used in equine therapeutics" suc