Information recently provided by the Kentucky Horse Racing Commission as well as many previous studies, including from the University of California at Davis, has shown that the vast majority of catastrophic injuries in racing horses are the end result of pre-existing injury, not freak “bad steps”.
Average age is around 3.5 years with other risk factors of 1 or fewer starts in the prior 30 days, no starts as a 2 year-old, few lifetime starts or coming off a 90 day lay up.
Many theories have been put forth to explain the catastrophic breakdowns in thoroughbred race horses. These include environmental factors such as shoeing and track surfaces, training protocols (too much or too little) and even suggestions that the breed is now genetically not capable of withstanding the forces imposed by racing.
There may be some truth to any of these, and I’m not here to render an opinion on that but rather to suggest there is another factor being overlooked completely – nutrition. Consider this. A 1999 study from U of California, Davis, reported that 97% of racehorses that had died or been euthanized for other reasons had degenerative bone lesions in the thoracic or lumbosacral spine.
These were flat racing horses. There is nothing about flat racing that would explain that staggering level of bone disease in the spine. The spine is the remaining area that is growing and maturing at a rapid rate in late yearlings and horses between the age of 2 and 5. This plus the fact there is underlying pre-existing bone disease as the real cause of catastrophic breakdowns points to nutritional failure.
How could this be when thoroughbreds in a post parade are arguably one of the most beautiful sights on earth. They are vibrant, muscled, shiny; seemingly the picture of health. This doesn’t necessarily reflect what is going on beneath the surface.
If a 2 YO horse’s bones are still growing, obviously that horse needs more minerals than an adult the same weight. If that horse is also being formally exercised and trying to remodel and strengthen bone as a result, even more minerals would be needed than the same horse just growing and not exercising. This is purely common sense and the current nutritional recommendations for mature horses exercising do call for a more mineral dense diet than for a horse at rest, but for the 2 YO they don’t.
In fact, the current recommendations for mineral density in the diet of working horses (grams of mineral per Mcal of calories) are actually lower for a 2 YO than an adult. Does that make sense? Not to me.
It will take formal studies looking specifically at bone health on various mineral density levels of the diet to answer this question definitively. I hope they occur soon because this is one element of injury in racehorses that is completely within our power to control. In the meantime, it could be wise to boost the mineral content of the diet for these horses using a high potency mineral supplement or balancer. Definitely in the can’t hurt, might help category.
Eleanor Kellon, VMD