Short heel, long toe: No, No!

The long toe, underslung heel trait is the most common hoof abnormality in horses. Here are ten reasons to take corrective measures for this conformation flaw, especially in the competition horse. Most are from Daniel Mark's Conformation and Soundness in the AAEP Proceedings, vol 46, 2000, p. 39.

Ten reasons to trim the toe

1. In a study of racehorses, researchers found that as the length of the toe increased by 1 inch, the odds of sustaining a carpal chip fracture increased by a factor of 40. (C. W. McIlwraith, Role of Conformation in Musculoskeletal Problems in the Racing Thoroughbred and Racing Quarter Horse, AAEP Proceedings, 2003).
2. Low hoof angles cause the heel to bear more weight, resulting in joint stress and heel pain. When the hoof angle is at a 39 degree angle, 75% of the weight goes to the heel; at 55 degrees, 43% is borne by the heels. The widest part of the foot is where the horse should land to effectively balance the hoof around the coffin bone.
   
   
3. Horses with long toes tend to land toe-first. Horses that land toe-first are those that are "closer to lameness" and considered by some veterinarians to be a grade one lame.
   
   
4. A toe-first landing means that the stride is shorter than normal (Ovnicek, G., How Hoof Form Relates to Hoof Function: Part 2, 9th Congress on Equine Medicine & Surgery).
   
   
5. Low hoof angles increase tension on the deep digital flexor tendon and compresses the navicular bone and rotary forces on the p3 bone (see picture above right--click on it to enlarge).
   
   
6. Underrun heels crush the digital cushion. The digital cushion does not regenerate well once significantly crushed. The longer the problem continues, the greater the overall damage to internal and external structures
   
   
   
7. The greater the weightbearing on a portion of hoof, the slower the growth (a vicious cycle).
   
   
   
8. Hoof tubules run from the top to the bottom of the hoof, and form the outer structure. Ideally they should be closer to vertical than horizontal. On underrun heels the tubules are bent forward, making the them less able to resist compression.
   
   
9. In a study of racehorse shoeing and hoof traits, researchers found that when there is disparity between the toe angle and heel angle, suspensory apparatus failure is more likely to occur. (Kane, A., Hoof balance characteristiscs associated with catastrophic injury of Thoroughbreds, AAEP Proceedings 1998).
   
   
10. Breakover is significantly delayed when the horse has a long toe and low hoof angle. The toe acts as a long lever arm, requiring more time and effort to rotate the heel around the toe. Imagine a athletic shoe (with a rolled toe) versus a clown shoe. The cross- trainer's shorter length and its breakover design allow for easier locomotion.