Our last program dealt with trimming of the horse's foot, specifically the toe. Dr. Steve O'Grady, a farrier and veterinarian, recently indicated that trimming the toe as short as possible reduces breakover, decreases strain on the deep digital flexor tendon, and decreases pressure on the navicular bone and other caudal heel structures. Today we will discuss the sole, heel support, and shoeing. Dr. O'Grady indicated the function of the sole is to support and protect the underlying structures and to bear some weight around the hoof wall. The sole should be firm and concave. Flattened soles are abnormal and prone to chronic bruising, a very common cause of lameness. Sole depth should be maintained by trimming back the toe so the dorsal hoof wall is aligned and by not removing excess live sole with the hoof knife. All loose, exfoliating material should be removed and the sole should be pared at the sole-wall junction to determine the amount of wall to be removed with nippers. The foot should be trimmed to support the heel so the frog, bars, and caudal surface of the heel should be the same height. Ideally, an imaginary line that bisects the cannon bone should intersect the most caudal extent of the hoof wall at the heel. The hoof should be checked to make sure the medial and lateral sides are even and the hoof is level.
If shoeing is necessary, Dr. O'Grady indicated that the shoe should be the lightest and simplest possible that provides traction, protection, and support. Breakover can be decreased by broadening the toe of the shoe and bringing the shoe back to, but not behind, the white line. The shoe should be long enough to cover the buttress of the heel and support the leg. The middle third of the frog should be equidistant from the toe and the heel. If the heel distance is too short, a longer shoe can be used. When nailing the shoe, use the fewest nails possible. All nails should be placed forward of the widest part of the hoof.