Throughout this week, our coverage of Santa Anita's spike in equine fatalities and subsequent indefinite closure has prompted all kinds of questions, comments, and theories from readers. Some are casual followers of the sport, just trying to get a handle on what's happening, while others are more long-term fans with questions about the underlying cause.
Some of these questions were ones we could answer by summoning our powers of data gathering; others required experts in their field.
Is this kind of spike in equine fatalities unusual?
Paulick Report: Unusual, but not unprecedented. In 2011-12, Aqueduct saw 21 horses die in the course of a season. An independent investigation of the deaths prompted numerous changes in safety and medication protocols. In 2016, Del Mar drew attention when 17 horses died in 36 days of racing. Track superintendent Dennis Moore made adjustments to Del Mar's surface, reduced morning workout traffic, and improved flagging systems to identify and scrutinize potentially at-risk horses. In 2017, 19 horses died during the Saratoga meet, up from 15 the year before. Officials there stepped up veterinary presence at the track and worked harder to identify at-risk horses. All three facilities saw numbers go down in subsequent seasons.
It does seem to be an unusual rate for Santa Anita, however. The California Horse Racing Board's 2017-18 annual report indicated there were 37 on-track deaths (racing and training) at the track for an entire year.
Generally, Santa Anita has tracked higher than the national average for racing fatalities in recent years. In 2017, the most recent year data was available, the track's rate was 2.36 fatalities per 1,000 starts. The national average that year was 1.61 (0.161 percent).
How do other countries' fatality rates compare to ours?
Paulick Report: It depends which racing authority you're looking at. Racing Victoria, the governing authority for racing in the state of Victoria, Australia, reports fatal racing accidents in 0.05 percent of starts. In 2017, the British Horseracing Authority reported a fatality rate of 0.18 percent across all racing (including steeplechase).
A word of caution, however – American racing isn't apples-to-apples with other countries' and there's no single reason for that. Turf racing is more heavily emphasized in other places (particularly Europe) and turf is known for better safety numbers than dirt. Medication policies, prize money, racing schedules, and other regulations – not to mention breeding – also mean there are probably many and various significant differences between their horses and ours.
What about historical data—did horses break down in the “good-ol' days”?
Paulick Report: Anecdotally yes, but we don't have good data on that. The Equine Injury Database only began collecting racing fatality statistics starting with the year 2009. While most American tracks now report to the EID, not all do, and it's just beginning to get data about workout fatalities.
Why are horses euthanized from a racing injury?
Paulick Report: Veterinarians make a determination about the horse's odds of recovery at or just after the time of injury. Many injuries to horses' limbs can now be resolved with surgery, including fractures that have resulted in small chips and the gnarly-looking spiral fracture that winds around a long bone like a cannon. Fractures that have broken the skin are not considered repairable because of the exposure of dirt and bacteria to the inside of the leg. Fractures which also involve the rupture of a soft tissue like the suspensory ligament (which runs from the back of the hoof, hooks on to the back of the ankle and continues to the upper cannon bone) are often too complex to repair.
Why can't horses just get prosthetic legs after a major injury?
Paulick Report: Some can, but it's not an effective solution for all types of injury, and not all horses can tolerate the recovery process. There's also significant risk of laminitis in the opposite limb (particularly if the prosthetic is in front, where horses carry 60 percent of their weight). A limited number of veterinarians are equipped and willing to attempt an amputation and prosthetic. The success rate for horses outfitted with prosthetics also aren't high, so for many it becomes a question of what's appropriate and fair to the individual.
Why is this spike in fatalities happening?
Paulick Report: We're not sure. With the recent increase in rain and decrease in temperatures, many suspect track surface has something to do with it, which is why surface experts Dennis Moore and Dr. Mick Peterson have been called in.
The Equine Injury Database has helped identify a number of risk factors that may contribute to an equine fatality during a race, but it also suggests there's a lot we don't yet know about what causes fatal injuries. In 2017, veterinarian and epidemiologist Dr. Tim Parkin revealed that his team has been able to explain just 35 percent of the improvement in fatality numbers in the databases' years of information gathering. There's another 65 percent of variance he doesn't have an explanation for.
What is currently done to keep horses safe?
Paulick Report: The California Horse Racing Board has a number of safety policies in place which put it ahead of many other jurisdictions. All horses are inspected by veterinarians pre-race, and those in identified risk groups may be inspected more than once. Horses on the veterinarian's list for unsoundness are added for increasing minimum stretches of time if they are flagged more than once in a year. The voided claim rule allows horses finishing a race unsound to be turned back if they are claimed, discouraging claiming trainers from attempting to run unsound horses. Necropsies are performed on all horses dying at California tracks, and trainers are given the option to participate in a review of any findings.
Is Santa Anita's dirt track composition drastically different from East Coast tracks?
Dr. Mick Peterson, Racing Surfaces Testing Laboratory: Yes, but the differences are pretty small even though the effect may be significant. The base was also traditionally different; for example, the inner track at Aqueduct was limestone screenings for winter, the base on the outer was clay to hold water in the winter. They seem to be doing fine with just one track. The biggest difference is that the tracks in drier areas have a composition to hold water and in wetter areas they are sandier to dry more quickly.
Aren't horses running on undeveloped bones and joints – not just as 2-year-olds, but all horses?
Dr. Larry Bramlage: Roughly, this is a schedule of the disappearance of the growth plates. Skeletons mature from the ground up, and just because the growth plates are still there does not indicate anything related to injury. The one that's commonly followed is the growth plate at the distal end of the radius or what horsemen mean when they say 'Are the knees closed?' That was shown 30 years ago in a paper by Dr. Gabel at Ohio State that it had no relation to injury. That's because the skeletal age, or the maturity of the bones, is not the thing that causes the horse problems – it's adaptation to training.
Most people that have some passing interest in horses think you should wait until the horse is fully mature and has no growth plates in its limbs – that would be four or five years old. The growth plates in the withers, those are going to be there until they're 12 or 13, if that gives you an indication of the fact the growth plates aren't all that important as far as skeletal maturity. But the people who think you should wait until the growth plates are gone before you start training, that gets proven to be wrong over and over in scientific studies. The reason is that as the horse finishes growing, he's got the blood supply and cell population that supports growth. What's best for the horse is to start training during that period of time and convert those support processes from growth to adaptation to training. The cells that would disappear because the skeleton is fully grown just switch jobs and start modeling the bones for the stress of training.
This all goes back to understanding that racehorses are not born with racehorse skeletons, they make them. The training is most effective when you catch the horse at the time they're most able to respond, which is roughly the time when they're two years old.
Could we blame non-steroidal anti-inflammatories (NSAIDs) like phenylbutazone and flunixin? Do those turn bones to “Swiss cheese” by weakening them and preventing healing?
Dr. Larry Bramlage: There's no data to support that. NSAIDs have been looked at in relation to bone physiology many, many times, both in horses and laboratory animals and sort of indirectly in people. The impetus for looking at that was wondering if you should have people who have fractures on any sort of nonsteroidal to make them more comfortable – the common one in people being ibuprofen. There's never been anything showing nonsteroidals impact healing at all, with one exception. There was one paper which showed a change, but it wasn't the quality of the bone healing itself, just the calendar. Bone healing is a process of step after step after step. This affected two of the steps, but not the long-term efficacy of the healing. Sometimes that study gets quoted as NSAIDs affecting bone healing but that's not really true. There's lots of work that shows NSAIDs don't have any significant effect on bone physiology.
What about Lasix? Doesn't that weaken the bone?
Dr. Larry Bramlage: There is a study by Kentucky Equine Research which shows Lasix does affect the total calcium outflow in the urine, but that is happening while the Lasix is effective. I think they looked at a 24-hour loss, but most of the change was in a few hours. That's a transient effect, and most horses waste calcium anyway. In other words, they're intaking way more calcium than they actually need. Horsemen can easily determine if this is the case by looking at their horses' urine. If it's cloudy, that's due to excess calcium. If it's perfectly clear, you might want to look at your horse's calcium balance, but most horses' urine is cloudy.
The effect of Lasix, that all started with a corollary paper in Scandinavia that showed elderly people who were on Lasix would have calcium deficiencies and increased fractures. The study initially blamed Lasix for the problem. When it was repeated, it turned out those people were on Lasix because they had cardiac disease and they were getting Lasix continuously. When they unraveled the whole scenario, they learned the fracture incidence was mostly fractures of the wrist due to falls. Those people were on medication for heart disease, and when you're on that you have lower blood pressure. When you stand up real quickly and your blood pressure is too low, you get postural hypotension, and you have an instant where you're a little vertigo and in a second it passes away. What was really happening was people were falling more and that was the reason for the increased fractures. When the study was repeated, that association between Lasix and fractures was disproved.
The practicality of the fact is horses are not on Lasix multiple times a day like people are when they have cardiac disease. In the overall scheme of calcium metabolism, it has very little effect. We tend to overfeed calcium to horses anyway.
Could this be bisphosphonates rearing their ugly heads?
Dr. Larry Bramlage: That's a question we don't really know. I doubt that the spate of injuries in California is directly related to bisphosphonates because if that were the case we'd see a generalized change throughout the horse industry. From my perspective looking at the healing of fractures after they've happened, the discussion about bisphosphonates really had a big effect in the horses that we see. The increased awareness that there's a cost for bisphosphonates has decreased the number of disturbed healing cases we see dramatically. I think the education process for horsemen really is working as far as letting them know bisphosphonates are not a good way to treat lameness [in young horses]. If you asked me the trend we're seeing with bisphosphonate usage, I'd say in the racing horses, it's down. I think people listened and grasped the situation and are responding.
The question people ask is “What if the horse got it as a yearling? Could that be predisposing them to injury?” If that were happening I'd expect we'd be seeing that at every racetrack and that is not the case.
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