Helen Writings
Laminitis is a serious hoof disease found in equines (e.g. horses, ponies, donkeys). Although it is very rare for laminitis to kill a horse directly, severe cases can result in the horse being put down for humane reasons (horse is in pain) or economic factors (horse is crippled and can no longer be used). Such euthanasia is sufficiently common that laminitis has become the second most common cause of premature horse death.
The term ‘laminitis’ refers to damage to the ‘laminae’, which is the connective tissues between the hoof bone (also known as the pedal bone) and the hoof wall. In mild cases of laminitis this tissue becomes inflamed and starts to break down. In more severe cases this connective tissue is sufficiently damaged that the hoof bone separates partly or completely from the hoof wall, rotating and sinking within the hoof. In extreme cases, the bone will actually penetrate the sole of the hoof. As the bone moves, it may also tear blood vessels and other tissues. Longer term, the damage to the hoof can result in permanent damage to the hoof growth and repair mechanisms, resulting in abnormal growth (e.g. flat or convex sole, rings in hoof wall, separation between hoof wall and sole).
One hears the term ‘founder’ in relation to ‘laminitis’. Unfortunately, not everyone uses the term in the same way. Some people use both terms interchangeably, while others use founder to describe the more serious cases of laminitis (e.g. bone penetration of the sole).
There are various causes of laminitis but they can be grouped into three categories. The first is overly rich feed, which upsets digestion, resulting in the release of toxins into the blood, where they then travel to the laminae and cause inflammation and tissue break down. The second category is mechanical separation, where the laminae is damaged from repeated shocks to the hooves (from running or jumping or hard ground). The third category is toxins, either ingested in the feed, or produced internally as a result of an infection.
Overly rich food changes the bacterial population in the intestines, with a subsequent release of toxins by the bacteria. It occurs when the horse received a large amount of food which is too high in carbohydrates or nitrogen. This can occur either with rich feed (e.g. grain or muesli) or lush pasture. Pasture is most likely to be too rich in spring, when rain follows a dry period, or when fertilizer has been used. As some breeds (especially ponies) are more sensitive, special care should be taken that neither their feed nor their pasture is too rich. When putting horses and ponies on rich pasture, one should limit the amount of grazing time and consider the use of a grazing muzzle to restrict the amount they eat.
Competition horses, such as jumping or racing horses, which are frequently worked on hard ground, are relatively likely to eventually develop laminitis. However, it can also occur in pleasure horses, if they work or travel on hard surfaces. Try to avoid use of your horse on hard ground. If it is necessary to travel on hard surfaces, try reducing the pace since a walking horse will have less hoof shock than a running horse. Ensuring that hoof trimming is correctly done, especially avoid trimming for long toes or over-trimming as these reduce the ability of the hooves to absorb shocks. If the horse is shoed, it should be done by a competent professional. Consider using shock-absorbing shoes (e.g. horse shoes with a rubber component) or shock absorbing boots during competitions (both are increasingly being used, even at the professional level).
Check that the horse’s feed does not contain any fungus, mold or chemicals. Do not allow them to eat chemically treated grass (e.g. herbicides). All serious infections should be aggressively and promptly treated, to prevent the release of infection related toxins into the blood stream.
This Laminitis and Founder article is part of the Horse Care series by Dr. Doug Stewart
Tags: equine, founder, horse, horse disease, horse illnesses, Horses, laminitis, pets
Posted in Horses · November 18th, 2009 · Comments (0)
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