Laminitis in Horses

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Laminitis is  a very painful and serious disease that can cause lameness in horses. The laminae is the support of the bony column in the foot. Once this supportive lining between the hoof wall and the bone becomes inflamed, it is called laminitis. There are two layers of laminae in the hoof. The sensitive laminae next to the bone, contains the blood, and the layer next to the hoof wall has no blood or nervous tissue and is called the insensitive laminae.

Major changes in normal gut bacteria produced when a horse eats too much grain, lush pasture or mares having retained placenta can cause laminitis.

Grass founder occurs most often, and is attributed to horses grazing lush spring or fall growth of cool season grasses. This growth is low in fiber and high in carbohydrates, or sugars. The fructans are chains of sugars made up of fructose molecules. Horses lack the enzyme enabling them to digest fructans, and they pass undigested to the hind gut, and undergo bacterial fermentation. Lactic acid is produced during fermentation, and effectively kills the normal hind gut bacteria. These dying bacteria release endotoxins, that are absorbed through the bloodstream, causing reduced blood flow to the laminae, and sometimes laminitis.

By limiting grazing during high growth periods, grain intake, having a regular feeding schedule, regular hoof trimming, vaccinations and deworming, horse owners can reduce the occurrences of laminitis.