Soiled Bedding Serves as a Vehicle for Drug Contamination

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" such as anti-inflammatories and analgesics, she said.

To reduce the risks, Popot said, strict adherence to stable hygiene guidelines should be followed, such as those outlined in the manual provided by the National Establishment for Higher Agronomical Learning at Dijon, which specifically addresses contamination. Such guidelines should apply not only to the stall, but also to the vehicle used to transport horses to and from competitions and to the stalls provided at the competition site itself.

Further research on environmental contamination is underway, Popot said.

About the Author

Christa Lesté-Lasserre, MA

Christa Lesté-Lasserre is a freelance writer based in France. A native of Dallas, Texas, Lesté-Lasserre grew up riding Quarter Horses, Appaloosas, and Shetland Ponies. She holds a master’s degree in English, specializing in creative writing, from the University of Mississippi in Oxford and earned a bachelor's in journalism and creative writing with a minor in sciences from Baylor University in Waco, Texas. She currently keeps her two Trakehners at home near Paris. Follow Lesté-Lasserre on Twitter @christalestelas.

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