Causes and Prevention of Laminitis and Founder in Horses

What are the Causes of Laminitis?

The hooves of horses are complex structures that support significant weight despite their relatively small size. Compounding the likelihood of damage to the intricate tissue of the inner hoof wall attachments is the restrictive hoof capsule that limits tissue swelling and increases pressure, much like a traumatic brain injury. There are many etiologies of laminitis and subsequent founder. Often the specific cause cannot be determined.

One primary cause of laminitis and subsequent founder occurs from undigested starch (carbohydrates) entering the caecum. This usually occurs either due to grain overload or grazing a pasture that has developed high sugar content grasses. The small intestinal tract can be presented with more carbohydrates than it can digest, the carbohydrates enter the hindgut, and the hindgut microbes begin to ferment these carbohydrates. The toxic microbial fermentation products not only enter the bloodstream but are also detrimental to the microbial population itself, creating a cascade of toxins that enter the bloodstream and damage the sensitive blood vessels within the hoof.

Although a different pathway, a metabolic problem such as hyperinsulinemia from insulin resistance will predispose a horse to laminitis.

Trauma from hooves repeatedly striking a hard surface, as with road founder, can lead to laminitis. A related causative factor occurs from excessive weight bearing on a limb due to opposing limb lameness. Other more common causative factors are the accumulation in the blood of toxic compounds produced by sepsis from an intestinal disturbance or a mare with a retained placenta.


Laminitis Prevention

Nutritional support with the nutrients required for strong and dense growth of the hoof wall and sole may help prevent a bout of laminitis progressing to a severe founder. Prior long term feeding of a quality hoof supplement may also benefit acute cases due to a strengthened cohesive bond between the hoof wall and the coffin bone.

Horses that tend to eat quickly are more likely to develop a digestive upset or carbohydrate overload. The feed is not chewed adequately and the digestion-assisting saliva is not sufficiently mixed with the feed. This unhealthy habit can be circumvented by adding fist-sized rounded rocks to the feed bucket.

Pasture grasses attempting to recover following a stress such as a frost or drought are most likely to produce excessive levels of sugars. Since the photosynthesis from sunlight is necessary for sugar production, and grass sugars are highest in the late afternoon and well into darkness, easy doers and laminitis prone horses are less likely to develop grass laminitis if they are only allowed pasture access in the early morning to early afternoon.

Although horses with acute (active) laminitis should not be fed whole oats, there is increasing awareness that horses that have had a history of laminitis in the past can be safely fed whole oats. This is due to the fact that the starch in oats is highly digestible. The starch in oats is quickly broken down into sugars in the small intestines and absorbed long before reaching the caecum. A highly digestible feed stuff, such as oats, is important to help prevent carbohydrates from entering the caecum. It is important to note that any concentrated feed stuff, including oats, should not be fed at more than 0.5% of their body weight any one feeding. This translates to a 500 kg horse receiving no more than 2.5 kg of feed (oats) per feeding. Ideally a horse receiving concentrates should be fed at least two to three times per day.

Treatment for Laminitis 

Proper veterinary and farrier treatment is vital to the horse’s prognosis. Providing nutritional support to connective tissue is also important. The accelerated growth of strengthened hoof wall resulting from providing a balance of nutrients supports laminitis recovery. Proper feed supplementation can help repair damage done during a laminitis/founder cycle. Many horses are being fed rations deficient in the nutrients necessary to maintain and rebuild their health after having suffered from laminitis and founder. Some hays are deficient in essential nutrients, especially those put up after being rained on, grown on nutrient deficient soils or harvested at a late stage of maturity.

Horses that have had an attack of laminitis need a supplement that contains ingredients to support the liver such as lecithin and thyroid building nutrients such as tyrosine and iodine. Amino acids play an important role in re-building a hoof damaged by laminitis and founder. Essential fatty acids and phospholipids are needed to build cell membranes and walls. Vitamin A and biotin are important hoof-building vitamins. Calcium, copper and zinc are important minerals for hoof strength. Please note however; for these nutrients to be most effective they must both be absorbable and in the proper ratio/balance.

A good supplement combines the hoof-building nutrients that are necessary to rebuild a strong hoof after tissue damage occurs during laminitis/founder.