Recreational drug use and the opiate epidemic have taken a great toll on the human population of the United States and beyond. Year over year, deaths from synthetic opioids—of which fentanyl ranks as the most prevalent—have skyrocketed, reaching 29,406 in 2017. Environmental transfer of drugs of human addiction to horses is nothing new. Cocaine and its primary metabolite, benzoylecgonine, have long been identified as environmental substances in post-race samples, and many jurisdictions have screening limits in place as a result. More recently, methamphetamine has begun to show up in post-race samples, reflecting the increasing addiction problem associated with this drug. In recognition of this growing problem, the National HBPA and North American Association of Racetrack Veterinarians made a Model Rule recommendation to the Association of Racing Commissioners International for screening limits for substances of human addiction in racing horses.
Fenger, Clara; Tobin, Thomas; Catignani, Maria; and Shults, Theodore, "Hitting the Threshold of Common Sense: The Time for Screening Limits to Guard Against Environmental Transfer Is Now" (2018). Maxwell H. Gluck Equine Research Center Faculty Publications. 40.