University of Kentucky blood study on racehorse track deaths
When three Thoroughbreds died at Keeneland last spring, racing fans were taken aback. Then 12 more died at Churchill Downs and in June the meet was moved to Ellis Park while officials tried to figure out what was going on.
No common factor has been identified as causing the fatalities, except for the obvious one: Racing itself.
In an effort to hopefully prevent tragedies on the track, an ongoing study at the University of Kentucky’s Gluck Equine Research Center has been looking for more than a decade for a way to find out which horses are vulnerable before they show any injury.
And they may have found it: Biomarkers in a horse’s blood that could be signs of microfractures and other invisible injuries.
Currently, until horses break down, their trainers, owners and even veterinarians presumably think they are healthy.
Dr. Sara Langsam, chair of the American Association of Equine Practitioners’ Racing Committee and a lifelong racing fan, called tests that could find undetectable invisible injuries “the next frontier.”
That “would allow us to predict catastrophic injury better before it happens,” Langsam said. “It would be huge, it would flag horses that would get early intervention.”
UK researchers study biomarkers in equine blood
Dr. Allen Page, a vet and scientist, has been working with a team that has identified what they think are at least six biomarkers, or biological markers, in blood that show if a horse is predisposed to injury.
Page has previously said the blood test is correct 75-80% of the time.
The work at UK’s Gluck Center originally looked for signs of inflammation after exercise but began zeroing in on messenger RNA, what he described as “the stepping stone between DNA and an actual protein,” as a way to predict injuries.
They examined around a thousand of blood samples taken from horses taken right after races and found three common mRNA markers; a second, deeper dive into the samples found three more, he said.
At least two of the markers appear to play a role in bone turnover and repair, Page said. Another is related to an anti-inflammatory protein, he said. They still aren’t sure exactly what the others might do.
“A lot of these horses do have underlying damage to the bone … but that damage is so small it’s not delectable by lameness exam or feeling the leg,” Page said.
To confirm their findings, the UK’s Gluck Center researchers have been conducting an 18-month-long study using blood samples taken at three California tracks to see if they can spot the biomarkers in horses before they were injured and detect changes in the estimated 15 or so that they think eventually will show an injury during the study period.
“We wanted to validate those findings,” Page said. “We were pretty confident those markers were there before the horse was injured – that those changes were there before the horse goes out to race.”
The sampling will end this fall and they will begin analyzing the data and hope to have results in 2024.
They have been collecting samples from every horse that runs — more than 15,000 samples — with the goal of showing how these particular biomarkers changed before the injury happened.
Even with this much data, the sample size will be small.
“In the event that what we’re doing doesn’t work, we’ll go back to the drawing board,” Page said. “But we hope it will validate the biomarkers and we can get to the point where the industry will have the additional tools that they need to identify horses they need to examine more closely.”
Because for all of the industry’s efforts, horses continue to face risks.
“We’re missing something,” Page said. There are stretches we go through with larger numbers of catastrophic injuries. And the public’s really sensitive to that.”
The fact that horses die on the track has become an increasing turnoff and not just for casual racing fans.
Is there a way, short of ending all racing, to keep horses safe?
“I think it’s pivotal (to stop horses breaking down),” said Langsam, who is a practicing racetrack vet in New York. “We’ve halved our injury rate in the last 10 years, but as society moves away from owning horses, our tolerance level for injuring horses is falling.”
Today, racehorses, including the ones that will go off when Keeneland’s Fall Meet races Oct. 6-28, go through multiple exams, including by independent vets who have the authority to scratch a questionable horse from a race over the objections of owners or trainers, as happened this year with Kentucky Derby favorite Forte.
The industry has implemented uniform drug standards and testing, created a national database of equine injuries designed to identify problems and funded a laboratory to test track surface safety.
But it hasn’t been enough.
After a particularly heart-breaking on-track death this summer at Saratoga in New York, where at least 14 horses died, there were renewed cries for the industry to do more to prevent deaths.
A report issued in September by the Horseracing Integrity and Safety Authority could not did not find “any singular explanation” for the Churchill fatalities. HISA recommended several changes and Churchill was allowed to resume racing this fall.
What will the blood test mean for racing?
Langsam, the New York vet, said that a blood test for specific markers could become a valuable screening tool that helps vets identify which horses are a higher risk.
“Tests like this would be more appropriate for identifying the subclinical horses, who might not even have changes in their stride yet,” she said. “You’re looking for something subtle, horses that are more at risk for injury, then we can do more in-depth tests because these horses don’t look abnormal.
“If we could have a screening test, or a sensor that will flag that individual, that’s the frontier we’re working on.”
Funding the next steps
But practical application could be years away. And even then it would might not be simple. Not every lab can do mRNA testing, for instance.
Dr. Stuart Brown, veterinarian, vice president for equine safety with Keeneland Association and Gluck Equine Research Foundation Board chair, said the test isn’t meant to be a raceday tool but could be incorporated in the pre-race process for horses coming into big races such as Kentucky Derby pre-races.
“This could be a valuable tool well before they ever get to race day. One more way to improve your confidence that that horse is safe to compete,” Brown said.
Because everyone in racing recognizes how devastating fatalities are.
“We talk about this, that we can never eliminate all the risk, and we feel terrible when we can’t, but we try real hard to. We go back within ourselves to look at what could we do differently,” Brown said. “Part of getting better is investing in this research. We don’t have a lot of huge funding, the money for the studies comes from private sector, have to carry our own bucket. Keeneland, the Stronach Group (which owns Santa Anita in California), Breeders Cup, the Jockey Club and many groups have come together. Otherwise this wouldn’t have gotten done.”
Nearly $500,000 has been spent on Page’s mRNA studies in the last six years, including $300,000 from the Kentucky Horse Racing Commission’s Equine Drug Research Council, of which Brown also is a former chair.
Brown considers it money well spent.
“I get up every morning at 4 o’clock in the morning to work with horsemen and their attending veterinarians,to make observations on individual horses at Keeneland training center, how they are handling the training process, how they are moving, handling preparation … this could become yet another tool,” Brown said. “I’d like to hope that it becomes another opportunity to have a sensitive indicator, a risk factor profile.
“We want to do everything we can, everything available to advocate first and foremost for the horse.”