Laminitis Prevention

Laminitis is a serious and common disease of the hoof. Although it is rarely fatal, in serious cases the horse is put down either for humane reasons (the horse is in pain and permanently crippled) or economic reasons (the horse can no longer be used for its intended purpose). Such cases of euthanasia are sufficiently common that laminitis is the second most common cause (after colic) of premature death in domestic horses.

The term 'laminitis' comes from 'laminae', which is the tissue which connects the hoof bone (correctly known as the pedal bone) to the hoof wall. Damage to this tissue is known as 'laminitis'. In mild cases the tissue becomes inflamed and begins to break down, reducing the strength of the bone-wall connection. In more severe cases the connection is reduced to the point that the bone begins to move, rotating within the hoof and sinking down. In extreme cases, the hoof will actually go through the sole of the hoof. As the bone moves, it can cause further damage to blood vessels and other surrounding tissues. Longer term, this damage affects the hoof repair and growth mechanisms, resulting in various types and degree of abnormal growth (e.g. convex or flat sole, hoof wall rings, separation of sole and hoof wall). In mild cases, the horse can return to normal activities. In more severe cases, the horse will need to be retired or put down.

The term 'founder' is related to 'laminitis', but is used in different ways by different people. Some people use the term founder interchangeably with laminitis, others to describe the more advanced forms of laminitis (e.g. substantial hoof bone movement or the bone penetrating the sole).

There are two main sources of damage to the laminae, leading to laminitis. One is toxins, which enter the blood and travel to the laminae, where they cause inflammation and tissue breakdown. The other is mechanical, where the laminae is damaged due to repeated shocks to the hoof (e.g. from running or jumping on hard surfaces).

In developed countries, toxic damage most often occurs when the pasture or feed is too high in carbohydrates or nitrogen. Consequently, one needs to avoid excessive amounts of rich feeds (e.g. grain) or lush pasture. Pasture is richer in the spring, after rain which follows a drought, or if it has been fertilized, so one should be careful of allowing sensitive breeds to graze on these pasture types. Some breeds are more sensitive than others and ponies are generally more sensitive than horses to rich food. For sensitive breeds one should restrict the amount of rich food (e.g. grain) and keep them off of rich pastures. One way to allow horses onto pasture but to restrict the amount eaten is to use a grazing muzzle.

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).

The third major cause of laminitis is toxins which are unrelated to overly rich feed. This includes toxins which are ingested (e.g. through moldy hay, or grass which has been treated with herbicides) or toxins which are produced due to an infection within the horse. Ensure that food does not contain fungus, mold or chemicals. Ensure that any infections are promptly and aggressively treated, before they can result in toxin overload leading to laminitis.

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