Hoof Wall Grooving
Vertical grooving often occurs along the medial (inside) and lateral (outside) toe quarters of the feet. Although the grooves are usually visible to the naked eye, slight depressions at the toe quarters (one on the inside and one on the outside) can been easily detected by sliding one's hand circumferentially around the hoof wall wall (starting from one side and moving toward the other side of the foot). The depressions are oriented vertically along the wall and almost always coincide with side clip placement of the shoe.
Vertical grooves along the hoof wall typically extend from the coronet band downward toward the ground (shoe) surface and terminate at the palmar (back) margin of the clips. The grooves represent the regions of the foot being "pinched" by the clips. Behind this groove, the heel quarters are trying to expand. In front of this groove, the toe quarters are also trying to expand. The foot is unable to expand at the level of the clips. Consequently a groove forms along the stress riser created at the junction of hoof wall that is experiencing two different forces.
The hoof wall is distorted in the groove and is therefore weaker than normal tissue. This coupled with stabilization of the wall at the level of the clips and expansion of the wall just behind and in front of the clips can result in the development of hoof wall cracks.
To learn more about hoof wall cracks click HERE.
Expansion or widening of the toe (sometimes referred to as "bull-nosing") often results from a lack of weightbearing stress along the dorsal (front) hoof wall. In a sense, the foot is slowly moving off of the front of the shoe. Concurrently, the heel quarters usually become more underrun, thereby increasing compressive stress (and compromise) to the back of the foot.
Vertical wall grooving is corrected via simple adjustments to the shoeing technique. Specifically, we generally recommend the following:
1) Shoe completely to the toe.
Most farriers "set" the shoe back and underneath the front of the foot in an attempt to quicken/ facilitate limb breakover. In many horses, however, setting the shoe deleteriously affects the internal biomechanics of the foot. By not fitting the toe we have eliminated weightbearing stress along the dorsal (front) of the hoof capsule. Consequently, the hoof wants to "squirt" off of the front of the shoe. The foot also tries to expand at the toe due to the lack of weightbearing stress coupled with forward movement of the hoof capsule. This desire to expand at the toe coupled with the presence side clips is the primary cause for "pinching".
By shoeing (completely) to the toe, we effectively implement weightbearing stress to the dorsal wall of the hoof. This in turn discourages both widening of the toe quarters and compromise of the heel quarters.
2) Move or eliminate the clips.
Repositioning or eliminating the clips will reduce pinching of the hoof capsule along the toe quarters of the foot. The stress riser created by the clips will no longer exist and the heel and toe quarters will be able to expand as one unit. Consequently, the groove will eventually disappear and the likelihood of associated hoof wall cracking will be dramatically reduced.
No clips, dorsal toe quarter clips (i.e. clips moved further forward on the foot) or a single toe clip (at the center of the toe) should alleviate current pinching along the sides of the foot and any associated vertical grooving.