OHRC announced today that its ongoing veterinary review of horses covered by recent Emergency Protective Orders has identified a significant number of horses showing findings consistent with thyrotoxicosis.

OKLAHOMA CITY, OK—JUNE 3, 2026–The Oklahoma Horse Racing Commission (“OHRC”) announced today that its ongoing veterinary review of horses covered by recent Emergency Protective Orders has identified a significant number of horses showing findings consistent with thyrotoxicosis, an extremely rare and serious condition involving excess circulating thyroid hormone.

To date, 68 of 96 horses evaluated across multiple trainers have shown findings consistent with this condition.

Thyrotoxicosis is exceptionally uncommon in horses and may cause elevated heart rate and respiration, hyperthermia, fatigue, weakness, muscle tremors, stiffness, and, in severe cases, collapse. Those findings are consistent with the kind of abnormal post-race distress that led OHRC’s Board of Stewards and veterinarians to take immediate protective action earlier this meet.

“The protection of the horse comes first,” said Amanda English, Executive Director of the Oklahoma Horse Racing Commission. “Our Stewards and veterinarians saw something that was not normal, trusted their experience, and acted when it mattered. That decision protected horses and allowed this Commission to uncover a serious medical problem that demanded attention.”

The three Emergency Protective Orders were issued after repeated incidents in which horses displayed severe post-race distress, including cases where horses could not safely leave the track under their own power. Those orders required the affected horses to be withheld from competition pending examination, testing, records review, and individualized veterinary clearance.

The Commission’s review remains ongoing. Each horse must proceed through a structured safety protocol that includes medical records review, diagnostic workups, veterinary assessment, and observed exercise before any return to competition may be considered. No horse will race unless and until OHRC veterinarians and the Board of Stewards are satisfied that the horse may safely compete without compromising equine welfare or the integrity of racing.

OHRC publicly recognized the courage and professionalism of its Stewards and veterinary team. “Faced with unusual and alarming conditions, they chose immediate protective action rather than delay. That decision is now producing critical answers,” said Director English.