I testified as part of the “Breeding, Drugs, and Breakdowns: The State of Thoroughbred Horseracing and the Welfare of the Thoroughbred Racehorse” Congressional hearing June 19. It was both disillusioning and enlightening. I naïvely thought I was invited along with three other veterinarians to talk about all the issues influencing fatal injuries in racehorses. I expected some tough questions and was looking forward to getting the facts as we know them out in the open, including the use of medication from a veterinarian’s perspective.
However, the positive work taking place wasn’t fully explored that day, and it is important that everyone with a stake in the racing industry understand the key research that is underway to significantly reduce the injury rate in racehorses.
A tremendous amount of study is being done by researchers on the factors that predispose a horse to injury. It is becoming clear that detecting the presence of existing damage to the horse’s musculoskeletal structure through early recognition techniques is critical to fracture prevention.
Our research group at Colorado State University, along with our collaborators, has demonstrated that the presence of “microdamage” in the bone can lead to the catastrophic fractures that we see in the fetlock joint (these include condylar and biaxial sesamoid fractures).
Researchers at the University of California, Davis have shown that stress fractures can be a precursor to catastrophic injury. Nuclear scintigraphy is effective in detecting these stress fractures, and early recognition has prevented numerous catastrophic injuries. The challenge is to identify the horse that shows no signs of lameness but has microdamage, which is essentially a fracture present in the earliest stages of development.
Getting horses routinely screened is the key to early detection. While CT scans and MRI are not practical for screening large groups of horses, the use of blood biomarkers and analysis offers the greatest potential for identifying at-risk horses. The principle behind biomarker testing is very straightforward: When cartilage and bone begin to break down early in the disease process, these products are released and can be measured by a laboratory test. An elevated test result indicates that the horse is potentially at risk for an injury.
At that point the horse can undergo a thorough diagnostic examination that involves nuclear scintigraphy or a CT scan.
In our most recent study funded by the Grayson-Jockey Club Research Foundation and done in racing Thoroughbreds in Southern California, we found that with sequential blood samples we could pick up changes in biomarkers six weeks before an injury occurred. Our accuracy rate in the study was approximately 70%, and we are striving to reach 100% accuracy.
The future vision is that we could identify a horse at risk through monthly samples of blood biomarkers. The idea is that the horse would be taken out of training, the microdamage could heal, and a catastrophic fracture would be prevented.
Reducing catastrophic injuries is the most important issue facing the racing industry, and we are hopeful that the biomarker test will soon be commercially available for use by the equine industry. We must protect the health of our equine athletes, and advances in veterinary research and technology are hopefully going to allow us to see a day when most horses receive care and treatment before a severe injury occurs. Other factors, such as racing surfaces and training regimens, must be evaluated for their roles in catastrophic injury, and a screening test is no substitute for proper horse management. We also must examine other purported injury factors, such as durability, 2-year-old racing, and medication. But an easy-to-use test is a significant step toward an injury-free horse.
Those are the positive developments that didn’t make the headlines from the Congressional hearing. There is good reason to be optimistic about efforts underway to protect the health and welfare of the horse. As a veterinarian, I am proud to be a part of these advances.
Dr. Wayne McIlwraith is professor of surgery and director of the Gail Holmes Equine Orthopaedic Research Center at Colorado State University