Conformation of the Pasterns and Hooves of HorsesBy Kentucky Equine Research Staff · September 15, 2011
The pastern should be in proportion to the rest of the leg length and at the same angle as the hoof wall (this is called the foot–pastern axis). A short, upright pastern increases concussion on the joints and can predispose a horse to arthritis or navicular disease. This type of conformation is often associated with straight shoulders.
A long, upright pastern predisposes to fetlock arthritis, but not ringbone. A long, sloping pastern is commonly seen in combination with sloping shoulders in rangy horses. This conformation puts extra strain on flexor tendons, suspensory ligaments, and the sesamoid bones.
Good hooves should have:
- The angle of the toe equaling the angle of the heel
- Thick walls with a glossy surface
- Concave and thick soles
- Large, well-developed, high and open heels
- Large, strong frogs
- Even length of heels
- Correct foot–pastern axis.
In addition hooves should be matching pairs, both front and hind, and should be neither too large nor too small for the horse.
The foot–pastern axis is an imaginary line viewed from the side that passes through the centre of the pastern and down through the hoof. The foot axis should follow the same axis as the pastern. In the front feet the foot–pastern axis should be between 45° and 50° to the ground. The hind feet are usually more pointed than the front and slightly more upright (50° to 55°), so the correct foot–pastern axis will also be in this range.
An examination of the foot flight patterns shows what tends to happen with different conformations.
- With a correct foot–pastern axis, the foot breaks over easily and is carried in a rounded arc of moderate height.
- If the pastern and hoof are too sloping, the foot is slower to break over and there is strain on the tendons at the back of the leg.
- If the pastern and hoof are too upright, the foot breaks over too quickly and lands hard, causing an increase in concussion.
- With a sloping pastern/upright hoof, the foot breaks over too quickly and lands hard (increased concussion) and the sloping pastern is under more strain along its front surface.
- With an upright pastern/sloping hoof, the foot is slower to break over and there is strain on the back of the pastern and the tendons of the leg.
Various faults in hoof conformation may lead to some degree of lameness.
- Flat feet: the hoof is large and the sole is close to the ground. Flat feet are more common in heavy breeds, but may also occur in Thoroughbreds. Horses with flat feet are prone to lameness from sole bruising.
- Contracted foot/heels: characterised by the back half of the foot appearing to be narrow. Bad shoeing can cause this defect. Because the heels cannot expand on contact with the ground, the foot does not absorb concussion as well as it should.
- Clubfoot: the foot has an axis of 60° or more, which increases concussion. This condition can be inherited or can occur because of a nutritional deficiency. It is possible for the defect to occur in one or more feet.
Brittle, shelly hoof walls are prone to cracking. Hooves that are too small lead to increased concussion. If the frog is poorly developed, the foot is less able to absorb concussion, which may lead to heel contraction. Dropped soles may occur after laminitis and are prone to bruising. Hoof wall rings may occur because of changes in the diet or season, fever, severe illness, or laminitis. Low or underrun heels can lead to heel bruising and more strain on the navicular bone and the tendons at the back of the leg.
This article is adapted, with permission, from Horse Sense—The Guide to Horse Care in Australia and New Zealand, second edition (2004).