When a foot is routinely trimmed too close at the toe each time the horse is shod, my research has shown that P3 seems to settle and the horse can be “off” for a few days. It is my belief that the sole ridge (callus) plays a major role in supporting P3 as shown in Figure 1. 

When the sole ridge is over-trimmed, the laminae attachment of P3 at the distal border may be compromised, allowing the hoof wall to move forward, much as it does with laminitis. The settling of P3 within the hoof capsule causes a vertical deformity in the hoof wall at the hairline. 

A common practice for farriers is to trim the toe and leave the heels alone to achieve proper pastern alignment¹. However, when farriers trim the sole close at the toe to raise the foot angle, the heels are frequently left too long. 

With the weakened laminae attachment at the distal border of P3, the hoof wall and long heels are pushed forward, allowing the entire hoof wall to migrate ahead of P3. This can be easily seen when viewed…