Description

Although a horse's hoofs are generally strong and crack-resistant, the weight and pressure placed on the hoofs may lead to cracks that can cause lameness, infection, and damage to the horse if not repaired. .

Horses hoofs are composed of keratin, the same material that makes up human fingernails and toenails. In addition, they contain thin, hollow tubes and layered sheets of keratin-filled cells. This structure is usually enough to stop cracks, but as the horse runs or moves over rough ground, the huge amount of weight and stress on the hoof can split the structure apart, and, once a crack is started, it tends to grow.

Types of cracks are usually identified as toe, quarter, or heel cracks, according to their location. Vertical cracks are classified as grass cracks (beginning at the ground surface and extending upward) or sand cracks (beginning at the coronet and extending downward). Horizontal cracks in the hoof wall are referred to as "blow-outs," which are usually inconsequential unless they weaken the hoof to the point that a vertical crack occurs.

Symptoms

• Visible breaks or cracks in the hoof wall
• Bleeding or discharge of blood and pus after exercise

Causes

Persistent hoof cracks are often related to an underlying problem, such as hoof wall damage. When the toe wall separates from the softer tissue underneath, it may be because of white line disease, the result of past hoof trauma, or other problems affecting the hoof wall.

Acute hoof cracks that occur suddenly are usually caused by severe trauma to the hoof.

Grass cracks occur in unshod hoofs when the bearing surface of the hoof wall is not trimmed and becomes too long. Percussion forces crack the hoof as the horse runs.

Sand cracks occur as the result of injuries to the coronet.

Too much moisture also causes hoof cracks, especially when repeated wet-to-dry periods cause expansion and contraction of the hoof wall.

Vitamin or amino acid deficiencies are a contributing factor in some cases of cracked hoofs.

Prevention

Although there is no way to prevent all hoof cracks, keeping horses appropriately shod, giving them consistent exercise with opportunity to toughen hooves, consistently following a program of daily inspections, hoof cleaning, and, when necessary, trimming, will drastically reduce the number and size of hoof cracks.

Good stall and paddock sanitation, plus protection from frequent wet-to-dry cycles during which the hoofs contract and expand, are important for good hoof health.

A balanced diet that provides adequate amounts of calcium, biotin, and the essential amio acids will also help keep a horse's hoofs in good shape.

Treatment

Once a horse develops hoof cracks of any kind, it is important to enlist the services of a good farrier. The involved area should be thoroughly examined and any debris or foreign material removed. The goal is to determine the cause of the crack and establish stability at the site of the crack.

In some cases, corrective shoeing may prevent further cracking. In other cases, a proper trimming and burning, or rasping a horizontal notch at the upper limit of the crack will keep it from growing. .

The crack may need to be sutured, utilizing screws, wires, and suturing materials. Acrylic compounds and space-age fabric, such as Kevlar or Spectra, are often used to fill, cover, protect, and correct the defect in the hoof.

When repairing a hoof crack, it is important to consider that the hoof crack can move in at least three dimensions. Therefore, it is important to allow for this movement as repairs are made. Braided fabrics and repair adhesives are specifically geared to work well in these kinds of applications.

If the crack is moist, bleeding, or discharging pus, it should be treated as a hoof or foot wound and should not be closed until the wound is treated and healed.