Continuing with the shape of interference it is a fair statement to say that it is not limited to the hoof shape alone. In fact, the shape of a horse’s conformation often dictates the form a hoof takes. Figure 1 is an example of a “cow hocked” trotter. The hind toes are turned outward and the cap of the hocks are turned inward toward each other. This creates a narrow stance that rotates out from the desired straight and forward line of travel. This type of conformation will cause the hind feet to land wider than normal when the horse is in motion. Any hoof placed on the ground wider than a straight-line stance must swing inward when released from the ground creating an arc instead of straight line. The inward swing of this arc is opportunity for interference from the front hoof in the moment of each stride when that front hoof is closest to the hind leg. It is also a less efficient gait. I would not say that “cow hocked” horses cannot go fast, clean, and earn money. It is simply an issue that we need to be aware of and address when shoeing these types.
Looking at these horses from the front view (Figure 2) it is beneficial to think about how that leg is loading while on the ground during each stride. This leg, as it lands in a wider stance, will load the lateral aspect of the tarsal joint (hock) more than the medial side and probably distort the hoof wall toward the lateral toe of the hoof. Both indications suggest that we should decrease the influence of the horseshoe in the lateral toe area. In this case I did so by hammering and grinding that part of the new shoe (Figure 3). Another approach is to increase the influence of the medial toe. I did this by fitting the shoe slightly wider than the hoof wall in the medial toe area. (picture 4) Lastly, I switched the shoes. The Kerckhaert full swedge hind shoe is designed to have a slightly wider and longer lateral branch. When putting those shoes on the opposite feet, I aim to reverse that dominant branch of the shoe to the other side of these hind hooves. This example at the very least will help to keep the shoe from exaggerating the issue by giving additional leverage to the lateral side, and at best, may keep a sounder horse, improve the gait efficiency, and minimize interference.
A farrier has an opportunity to help or hinder with many conformational issues. He or she does this by spending time in evaluation of each animal and the people around it. Paying attention to the shape of conformation as well its effect on locomotion and soundness is the most important factor in deciding what shoeing application will have the greatest opportunity to benefit. This is done best through the synergy of the people involved with the horse from groom, to trainer. Include with those the veterinarian and farrier, as well as other equine professionals and the horse will benefit; until the cows come home.