QUESTION: It seems Thoroughbred horses are prone to low heel and long toes. Have you found this to be true, and is it good or bad for a racehorse?
DR. RAUL BRAS: The low heel-long toes trait is one of the most common hoof abnormalities described in the racehorse. Functionally adapted for speed and efficient use of energy, the Thoroughbred foot is light and prone to hoof capsule distortion. Hoof capsule distortion refers to hoof abnormalities such as under-run, collapsed or crushed heels. Hoof capsule distortions occur slowly over time and are the result of long-term abnormal weight bearing.
The typical Thoroughbred conformation of a longer, more sloping pastern places more force on the heel region. Repetitive speed training in racehorses decreases hoof angle over time and as hoof angle decreases, more stress is placed on the heel region. Once the process begins, several major support components fail simultaneously. As the heel angle decreases, so does digital cushion mass. As cushion mass becomes compressed, shock-absorbing abilities are greatly reduced, passing excessive load to the heel tubules, which quickly fold inward and forward. As the heel tubules fold the bars lose their strategic shape and location, which is strongest when close to the widest part of the frog.
The routine of most athletic horses is characterized by many hours of inactivity. This lifestyle has a negative effect on the circulation of the foot, and it contributes to horn distortion more than any normal activity. Subtle but steady deterioration may be occurring in the horn, soft tissue, bone and circulation of the foot – all the while the horse is doing nothing. Intense exercise during training and competition then becomes a major trigger for overload and, ultimately, distortion of the weakened hoof capsule.
Farriers worldwide have been unjustly accused of taking the heel off of horses with the long toe/low heel appearance. This is not actually the case, however, as other factors contributed to the demise of the heel. This is not a problem with your farrier, but a problem for your farrier. Backing up toes to seemingly correct the long toe/underrun heel foot may appear to make the heel take on a more balanced relationship with the ground. However, the toe only appears long because there is no heel.
The veterinary and horseshoeing literature has promoted a fairly, perfectly equal shape and symmetrical hoof capsule. There is evidence that trimming the feet to make the lateral and medial walls equidistant from the frog is associated with unsoundness in racehorses.
As with many other types of foot related lameness, prevention is much more effective than treatment. Prevention begins with careful observation.
Dr. Raul Bras is a certified journeyman farrier and veterinarian in the podiatry department at Rood and Riddle Equine Hospital. A member of the International Equine Veterinarian Hall of Fame, Bras graduated from Ross University and completed the farrier program at Cornell University. He is a partner at Rood and Riddle.
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