Hoof cracks are horizontal or vertical fissures that occur in the hoof wall (see hoof crack image).
Etiology and Pathophysiology of Hoof Cracks in Horses
Hoof cracks in horses are thought to result mainly from excessive forces placed on the hoof wall. Hoof cracks can occur in a horizontal or vertical orientation; they can be further classified by location, depth, and length.
Full-thickness cracks extend through the entire thickness of the hoof capsule.
Partial-thickness cracks extend through only part of the thickness of the hoof capsule.
Complete hoof cracks extend from the ground surface of the hoof wall to the coronary band.
Incomplete cracks start either distally or proximally but do not extend the entire length of the wall.
Courtesy of Dr. Brian Beasley.
Hoof cracks can be located anywhere around the circumference of the hoof wall, including the bars.
Predisposing factors for the development of hoof cracks in horses include hoof wall imbalances, trauma to the coronary band, poor-quality hoof wall, and inadequate or infrequent trimming. Vertically oriented hoof cracks are the most common type and are generally attributed to hoof wall imbalances that arise from conformational abnormalities or improper trimming and shoeing. However, hoof cracks can occur in hooves that appear normal and have been adequately trimmed or shod.
Horses with sheared heels seem to be more prone to the development of quarter cracks. In these cases, the associated displacement of the coronary band may cause the collateral cartilage to affect the axial surface of the coronary band, contributing to formation of a crack. A true quarter crack originates at the coronary band and can lead to hoof wall instability, inflammation, and infection.
Courtesy of Dr. Brian Beasley.
Toe cracks are usually partial-thickness cracks that originate at the ground surface of the hoof wall (see toe crack image).
Horizontal hoof cracks are less common than vertical hoof cracks. Horizontal cracks usually involve a relatively small proportion of the circumference of the wall and occur after an abscess that has ruptured at the coronary band. Selenium toxicosis can cause horizontal hoof cracks that extend the entire circumference of the hoof wall.
Clinical Findings of Hoof Cracks in Horses
Most hoof cracks in horses are visible as fissures in the hoof wall.
Usually, lameness is present only with an unstable or infected full-thickness hoof crack. If there is instability, the width of the crack changes when the hoof is loaded and unloaded.
Digital pressure on the coronary band proximal to a quarter hoof crack usually elicits a painful response if the crack extends into sensitive tissue.
Diagnosis of Hoof Cracks in Horses
Most hoof cracks in horses are evident upon visual examination. Some small cracks near the coronary band or in the bar portion of the hoof wall may require closer inspection.
Foot radiography may help identify underlying hoof imbalance conditions if present.
Diagnostic analgesia may be necessary to determine whether a hoof crack is the source of lameness.
Treatment and Management of Hoof Cracks in Horses
Most partial-thickness hoof cracks do not cause lameness in horses; therefore, treatment would have only cosmetic purposes.
With lameness-inducing hoof cracks (such as true quarter cracks), the goals of treatment are to identify and treat underlying causes, to debride affected tissues, and to stabilize the hoof wall if necessary.
Many repair techniques and shoeing options exist for hoof crack repair. Appropriate trimming and balance of the foot are essential for efficient healing and longterm management. Stabilization of the crack, along with appropriate trimming or shoeing, often enables the horse to continue working while the crack grows out. Whatever method of repair is used, the goal is to achieve adequate stability of the hoof wall adjacent to the crack.
Infected or bleeding cracks should not be completely covered by a patch or adhesive, because an abscess could form as a result.
The prognosis for hoof cracks in horses varies depending on the location and depth of the crack. The prognosis is good when an underlying cause, such as foot imbalance, can be identified and corrected. Cracks associated with uncorrectable causes may require indefinite therapeutic farriery.
Key Points
Hoof cracks are horizontal or vertical fissures that occur in the hoof wall.
Usually, lameness is present with only unstable or infected full-thickness hoof cracks.
Digital pressure on the coronary band proximal to a vertical hoof crack usually elicits a painful response if the crack is pathological.
For More Information
Moyer, W. Hoof wall defects: chronic hoof wall separations and hoof wall cracks. Vet Clin North Am Equine Pract. 2002;19(2):463-477. doi:10.1016/s0749-0739(03)00003-8
Also see pet health content regarding hoof cracks in horses.
