HISA warns unsound horses face higher fatal injury risk

A horse that comes back off the Veterinarians’ List as unsound is not just clearing paperwork. It is stepping back into a zone where HISA now says the odds of a fatal outcome are elevated, and that warning will sharpen scrutiny at the entry box, the barn and the morning workout track before the sport’s biggest meets.

The Horseracing Integrity and Safety Authority issued the advisory on May 8, tying the risk to data from its own Veterinarians’ List. HISA said 3,297 unique horses were placed on that list as unsound in 2025, and as of March 31, 1,904 of them had not made a subsequent start. That is nearly 60 percent of the group. HISA also said that through the end of the first quarter of 2026, about 20 percent of racing- and training-related fatalities at covered racetracks involved horses that were either still on the list when they died, had been scratched as unsound before a recent race, or had been removed from the list within the previous six months.

That is the number that matters when a horse is entered for a graded-stakes day or a major meet. A runner cleared to train again can still face closer veterinary review, more conservative decisions from trainers, and more pressure on connections weighing whether to send a horse back in too soon. HISA said the advisory includes practical guidance such as wearable biometric sensors during training, a sign that the authority wants more data before a horse is asked to run again.

Dr. Jennifer Durenberger, HISA’s director of policy and industry initiatives, said regulatory veterinarians place horses on the list with “utmost care and expertise,” and she stressed the need for strong collaboration among regulatory veterinarians, trainers and attending veterinarians. The message lands in a sport already arguing over how aggressively horses should be scratched and whether some vets are too quick to pull a horse from a race. Daily Racing Form noted that debate has intensified alongside a lawsuit filed last month by the connections of White Abarrio over the colt’s pre-race scratch from last year’s Breeders’ Cup Dirt Mile.

The new warning was HISA’s fourth Equine Health Advisory, following previous advisories on proximal forelimb fractures, exercise-associated sudden death and proximal hindlimb fractures. It also fits into HISA’s broader effort to standardize the Veterinarians’ List and Stewards’ List, a review launched on December 8, 2025, with changes targeted for 2026. HISA said the current list categories are legacy systems that vary widely across states and racetracks, complicating national safety comparisons. The American Veterinary Medical Association says horses can be placed on the list for illness, injury, epistaxis, shockwave treatment, signs of physical distress, unsoundness or recency-related issues.