Competing horses with subclinical lameness that is masked by medication is a widespread welfare concern in equestrian sport, and regulatory reform is targeting both medication use and pre-competition veterinary assessment.
Competition lameness is a welfare problem driven by the economic pressures of elite equestrian sport. Horses with structural joint problems that are not acutely lame may compete with subclinical pain. Injections that reduce joint inflammation enable competition on joints that need rest and treatment. Regulatory systems designed to prevent doping are not well-calibrated to detect welfare-compromising competition of lame horses. The welfare obligation is clear: horses should not compete when in pain regardless of whether medication has masked acute lameness. Pre-competition welfare assessment independent of anti-doping enforcement is needed.