The heel on a healthy hoof is short and steep. The frog makes light contact with the ground, and the quarters are free to expand with it. The digital cushion at the back is large and fatty. By nurturing these structures, the hoof continues the essential ‘heel first landing’.
When these structures are neglected (commonly through shoeing) the hoof becomes flat and the heels grow forwards. The position of the hoof’s landing surface changes. The heel angle becomes less steep than that of the outer hoof wall.
These are under-run heels. Suddenly, the hoof is in an unnatural position in relation to the coffin bone. The area of direct pressure has moved, from behind the coffin bone to underneath it.
This puts immense strain on the navicular bone and soft tissues within. Under such pain, the horse’s only option is to move his landing to the toes, further weakening the hoof.
As you’ve probably gathered, under-run heels are rarely a ‘heel only problem’. You must focus on the health of the entire hoof capsule.
To begin, a forward growing toe almost always accompanies the problem. Start by backing up the toe, moving the base into the correct position.
Next, make sure the hoof isn’t flat. This means applying the mustang roll, but also scooping the quarters to the correct height. When the quarters are left too long, bulging appears in the hoof wall above them. This forces the hoof to grow forwards, rather than down.
Always shorten under-run heels that have grown too long. As usual, the sole at the hoof’s seat of corn will direct you on the height of the heels.
These measures cannot bring immediate soundness. Strong hooves are grown, not trimmed. However, shortening the heels and removing the cause of abnormal growth will soon bring your horse’s under-run heels into check.
Always watch your horse’s hooves to make sure they’re growing properly, and keep trimming when they need help.
Thanks for your comments. While I caeirtnly agree there are differences between these feet, I’d like to clarify the reasons for the differences.The symmetry of a hoof is determined by the set of (in this case) the horse’s shoulders. When a horse’s base of support (the distance between his hooves) varies from directly below his shoulders, you’ll see medial/lateral asymmetry appear, with the mass of the hoof distributed more towards the side less under the animal. In other words, if the horse has a very wide base of support, he will generally have more hoof on the outside (lateral) portion of his hoof with respect to the bones of the leg. There will also be a more upright hoof wall on the inside (medial side), presumably because the direction of impact on the horn tubules is more vertical. You’ll also observe asymmetry when the set of the horse’s shoulders causes the plane of movement described by the limb to be non-parallel to the horse’s direction of movement i.e. the horse is splay-footed or pigeon-toed. But if the hoof is being properly trimmed, evidenced by straight growth and no flaring, symmetry then becomes entirely a consequence of conformation and movement. The Warmblood, therefore, was not trimmed for symmetry he’s just a more symmetrical horse!I tend to get very particular about word choices, because I’m very concerned about a proper understanding of cause and effect. So yes, the tubules do tend to curve under at the ground in the feral horse, but I don’t think they’re driven to do it to protect the connection between sole and wall. Rather, it’s the consequence of a whole lot of travel over very abrasive terrain, and has everything to do with the direction of impact on the tubules. The domestic horse, on the other hand, simply doesn’t move enough to experience that same bending, although we do emulate the bending/wear by applying the mustang roll to the domestic hoof, with the same advantages to the horse less potential tearing forces at the white line, and easier breakover. And, finally, I have to say I disagree that there’s more balance/strength in the wild foot. I believe both feet serve the needs of each horse, which, after all, is their role. Yes, the feral horse hoof has more arch and concavity than the Warmblood’s, but that’s purely a function of the horse’s size.Thanks again!Steve
I see a lot of horses with under-run heels and long toes and so far all of the ones I’ve had to work with were grade 1 or 2 lame in one or both front feet. I think some horses’ hooves have a tendency to grow that way but if trimmed in the manner I think you are suggesting, with or without, shoes can help these horses. I’m familiar with the work done by Jamie Jackson, Gene Ovnicek, and Dr. Ric Redden and believe the type of trim they recommend will produce healthy hooves. Finding someone who is correctly trained in the technique is difficult.