According to an old saying, there are only two types of ponies: those with laminitis and those waiting to get laminitis. While we hope this isn’t true, it’s unfortunate that ponies – and all types of horses – are highly vulnerable to laminitis.

Laminitis is not a disease; it is usually a symptom or sign of a more systemic challenge to the horse’s system. A typical sign of laminitis includes lameness, and extreme laminitis causes the horse to rock back on the hind legs to take weight off the front feet, as well as reclining for extended periods.

What’s the Cause?
1. Fat Horse
Obesity is a leading cause of laminitis because extra weight adds tremendous strain to a horse’s hoof wall. Problems are compounded when heavy animals have small feet. Sometimes, laminitis occurs slowly; other times, it progresses rapidly. To minimize laminitis, keep your horses in a condition score of 5 or 6 (see sidebar below: Body Condition Scoring).

2. Foot Trauma
Trauma to the feet causes damage to the laminae of the hoof, resulting in laminitis. Road founder is usually the result of animals being worked on hard surfaces without adequate foot protection. Shoes can be a sufficient aid, but pads might be necessary if the horse is particularly sensitive.

3. Retained Placenta
Broodmares that retain their placenta for six or more hours post parturition – and those that retain placenta tags – are likely to develop laminitis. A decaying placenta generates toxic materials that can cause laminitis. Call your veterinarian if your mare retains her placenta longer than six hours. Minimize risk by removing the placenta immediately, and treat the uterus to minimize production of toxins. Also, examine the placenta immediately following parturition to ensure that it has been expelled intact. Any sign that the mare retained a portion of the placenta warrants veterinary assistance.

4. Abdominal Surgery/Other Trauma
Horses requiring abdominal surgery are vulnerable to laminitis, which might be due to alterations to the gut microflora, systemic trauma or drug treatment. Gradually bring horses back on feed after surgery. A number of drug treatment programs, both medical and non-medical, can cause systemic reactions, resulting in laminitis. Ask your veterinarian about the risks of subjecting your horse to long-term medications. Horses that experience severe injury to one leg often develop laminitis in the “off” hoof, due to excessive weight bearing on the sound limb.

5. Certain Shavings
Walnut shavings – and some other woods – have been shown to initiate laminitis. The condition is probably caused by the animal absorbing chemicals in the wood directly through the sole of the foot. Use only soft wood shavings.

6. Feed Overload and Change
The classical cause of nutritional laminitis is allowing the horse access to the feed room. Feeding too much concentrate at one time, abrupt changes in the feeding program and changing from a high-forage program to a high-starch concentrate program can cause laminitis. The other likely cause of nutritional laminitis is allowing consumption of large amounts of lush spring grass or winter forage, such as ryegrass. If you feed these forages, introduce them slowly.

Scrutinize Diets
In each of the above feed-related scenarios, laminitis could occur because of increased consumption of more highly digestible carbohydrate (starch or sugar) than a horse can digest in the small intestine. With the overload of starch, normal gut microorganisms release toxins, causing serious reactions in the body, such as an alteration of the blood flow to the hoof. When this occurs, laminae connecting the hoof wall to the underlying tissues becomes damaged. The damaged laminae allow the deep flexor tendon to pull the coffin bone down, causing separation of the hoof wall from the coffin bone. This can be followed by the coffin bone penetrating the sole of the foot. The condition is very painful to the horse – and if not managed quickly – can be terminal.

Management
If your veterinarian and farrier can make your laminitic horse comfortable, it could still take nine to 12 months to bring it back into service. This does not guarantee soundness, and the horse will likely need special care. Even though the laminitic hoof can appear to be normal after a bout with laminitis, considerable scar tissue has replaced the laminae, making the hoof vulnerable to additional damage. Beware of a relapse.

Put overweight horses on diets until body condition returns to a 4 to 5. Forage, minerals and water can be the best choice for horses that require minimum calories. For some, even forage must be controlled.
Avoid winter pastures, ryegrass, oats, rye and wheat for easy keepers. The high concentration of soluble sugars in these forages results in considerable amounts of highly fermentable products getting to the cecum and colon, resulting in rapid fermentation and low hind gut pH. The same caution should be applied to new spring grass. Grass hays from these same crops aren’t usually a problem because the hay has low concentrations of highly fermentable sugars.

Animals that cannot support appropriate body condition on forage alone should eat a low-starch concentrate for additional energy. Low-starch concentrates provide energy to the animal via highly fermentable fiber sources such as soybean hulls, beet pulp, wheat bran, rice bran and fat.
Another alternative: Use complete, commercially formulated diets composed of forage, highly fermentable fiber sources, and fat that provide nutrients via a low-starch, low-sugar product. Recently, Seminole Feed released “Happy Hoof,” formulated especially for laminitic-prone horses and ponies.

Supplements
Feed supplements can benefit hoof growth, replacing the damaged hoof wall. Synthesis of the hoof wall is, however, dependent on an adequate supply nutrients. Key nutrients in hoof wall synthesis include protein, minerals and vitamins. Protein is a source of the amino acids required to build keratin, the hoof wall protein. A key amino acid in keratin is cystine, which the animal synthesizes from methionine. Vitamin A and biotin, a B-complex vitamin, will also influence hoof growth and hoof wall quality. The amount of supplemental biotin required varies some with the basic diet, but 30 mg/day seems to be adequate for maximum response in most horses. Lower levels might be appropriate after initial hoof growth. Calcium is important for hoof growth, as well as the trace minerals zinc, manganese and copper. These trace minerals should provide 30 to 50 percent of the total mineral supplementation.

Remember
To minimize the occurrence of laminitis, feed small amounts of concentrate often, avoid rapid changes in feeding, control weight and limit high-sugar forages such as spring grass and winter forages. Eliminate high-starch concentrates. Feed forage, minerals, and water if the horse can maintain appropriate body condition on this program. If the concentrate is needed to maintain body condition, use high-fiber, high-fat products. Always provide balanced nutrients to support hoof growth.

Dr. Ed Ott, a past chairman of the National Research Council, is a professor of animal nutrition at the University of Florida, where he is also professor-in-charge of the UF Horse Research Center. Stay up updated with Dr. Ott’s findings by reading Seminole EquiFlash articles, available online at www.seminolefeed.com.