Description

The terms founder and laminitis are often used interchangeably by authorities. However, founder usually refers to a chronic or long-term condition associated with rotation of the coffin bone in the foot of the horse, while laminitis refers to symptoms associated with a sudden attack, including pain and inflammation of the laminae.

Founder begins as a vascular and metabolic disease associated with a breakdown within the laminae in the horse's hoof. This inflammation interferes with the wall and bone bond and leads to a break down in the anatomy of the foot.

As endotoxins and lactic acid dilate the large arteries in the horse's foot and cause constriction of the small capillary vessels that nourish the laminae, the laminae begin to swell, causing tissue damage.

When this happens, the coffin bone may become detached from the wall, rotate, or sink, and often penetrates the sole. The horse becomes obviously lame and may refuse to stand or walk. Unless treated promptly the horse will become chronically lame and euthanasia may be necessary if the hoof breakdown is complete and untreatable.

Symptoms

• Lameness
• Heat in feet
• Increased digital pulse in feet
• Pain response to hoof testers
• Reluctant or hesitant gait - "walking on egg shells"
• Reluctance to stand
• Rings in hoof wall that become wider from toe to heel
• Stone bruises
• Widened white line with abscesses
• Dropped soles or flat feet

Causes

Although founder occurs in the feet, the underlying cause often originates elsewhere in the horse's body.

Despite the huge welfare issues associated with founder, vets and scientists still don’t fully understand the precise cause of this condition; however, researchers are getting closer to understanding the changes that occur in the hoof during the developmental stages.

Hoof shape and lack of regular, correct trimming are often thought to be the main causes of founder. Some authorities firmly believe that founder is caused by overfeeding, especially with carbohydrates, to the point that the horse is overweight, with accompanying digestive upset.

Access to excessive amounts of lush forage, toxins released within the horse's system, high fever, excessive concussion to the feet, and prolonged use of high doses of corticosteroids are also believed to be possible factors in the development of founder. Heavy breeds of horses, such as draft horses, seem to be more susceptible to the disease.

Prevention

Management is the key to reducing the incidence of founder, and much of the current research is investigating potential trigger factors as well as the events that may culminate in founder. This research will hopefully enable founder prevention strategies to be targeted more effectively.

Preventive management includes keeping a horse's hoofs trimmed properly on a weekly basis, keeping the horse on firm, non-concussive ground, and being careful when working on hard or rocky ground to prevent stone bruises and injuries.

Horses should not be overfed to the point of becoming overweight, and they should not be over watered after exercise. Appropriate medications should be used only when necessary, and changes to routine should be made slowly and progressively to avoid stress.

Gastrointestinal problems should be treated promptly by a veterinarian to avoid extended illnesses. Prolonged transportation should be avoided, and, if necessary, should be done in stages, with periods of rest and regular exercise to assure good circulation in legs and feet.

Treatment

With cooperation between a veterinarian and a qualified farrier, the chances for recovery from founder are good; however, if not treated immediately, irreparable damage may be done, and if the condition becomes too severe, the horse may need to be euthanized for humane reasons.

The sooner treatment begins, the better the chance for recovery. Treatment of founder depends on specific circumstances and will vary according to the severity of the condition. Stabling the horse on soft ground, such as sand or shavings, with the administration of painkillers and anti-inflammatories will help the horse find some level of comfort.

Antibiotics to fight infection and anti-endotoxins to reduce bacterial toxicity, along with anticoagulants and vasodilators to improve blood flow to the feet, may be deemed necessary by a veterinarian.

Opening and draining any abscesses, and corrective hoof trimming and shoeing by a farrier, will help promote healing and also help in preventing further episodes of the disease.

Careful attention to trimming the hooves properly and working the horse barefoot on firm, non-concussive ground during the recovery period will help increase circulation and help restore the coffin bone to a ground-parallel position for maximum hoof health.

If the horse is overweight, imposing dietary restrictions to prevent overeating and obesity is extremely important. Using a feeding program that simulates grazing for feed by providing small amounts of hay spread throughout a paddock or area to promote light exercise may also be helpful in treating founder.