How to Avoid Laminitis and Founder
By: Dr. Douglas Stewart
Laminitis is a common illness of the hoof and is the second most frequent cause of premature death in horses. Although it is very rare for laminitis to kill a horse directly, it often results in euthanasia for humane reasons (the horse is crippled or in permanent pain) or practical reasons (e.g. the horse is unable to continue its normal activities). In addition to the horses which are put down, many others survive but are left permanently disabled or in pain.
The term ‘laminitis’ refers to damage to the ‘laminae’, which is the tissue which connects the hoof bone (correctly known as the ‘pedal bone’) to the hoof wall. When the laminae tissue is damaged, the pedal bone can move out of position. Depending on the nature an severity of the laminitis, this can result it:
– Rotation of the hoof bones within the hoof.
– The hoof bones sinking down lower into the hoof and in extreme cases penetrating the sole of the hoof.
– Damage to various tissues and blood vessels.
– Permanent changes to the hoof growth mechanisms, resulting in abnormal growth patterns (e.g. flattened or convex sole, visible rings in the hoof wall, separation between hoof wall and sole). The term ‘founder’ is an informal term for laminitis. Some people use the word founder to mean any type of laminitis, while others use it to describe the more severe forms of laminitis (e.g. when the pedal bone penetrates the sole of the hoof). Laminitis has various causes but these can be summarized into two groups:
– Toxins. The release of certain toxins (poisons) into the blood stream will result in damage to the laminae. Such toxins can result from external sources (e.g. what the horse eats), internal sources (e.g. toxins produced by an infection) and in some cases certain medications.
– Mechanical. Repeated shocks to the hoof (e.g. running over a hard surface for a long time) can damage the laminae.
The main cause of laminitis in developed countries (e.g. UK, USA) is food which is too high in carbohydrates or nitrogen, resulting in toxins being released from the digestive system. Consequently, one needs to avoid excessive amounts of rich feeds (e.g. grain) or lush pasture, with special care being taken with ponies or horse breeds which are most sensitive. For the most sensitive breeds (especially if there is obesity as well), even normal grass may be too rich and they may need to be kept on ‘poor’ pasture or be part-fed with feed that is low in carbohydrates and high in fiber. In addition to restricting the absolute amount, one should also introduce horse gradually to rich feeds or pasture, both to allow their systems to adjust (note that there is a maximum limit to which they can adjust) and also to avoid the additional risk of gorging. One means to restrict the amount of grass eaten, while still allowing the horse access to pasture, is to use a grazing muzzle.
The second most common cause is mechanical separation. To minimize the risk of this:
– Avoid use of the horse on hard surfaces. When it is necessary to travel on hard surfaces, reduce the pace of the horse as a walking horse will have less shock to its feet than a running horse.
– Ensure that feet are correctly trimmed. In particular, avoid over-trimming and trimming for long toes. If the horse has shoes, ensure that the shoeing is done by a competent professional.
– Shock absorbing shoes and boots are being increasing used, even in competitions, to protect not only against laminitis but other shock-related injuries.
– Avoid over-feeding your horse, as obesity increases the risk of laminitis and other illnesses. The third most common cause is external or internal toxins:
– Monitor your horse so that you can quickly identify and treat illnesses.
– Ensure that their food does not contain fungus, mold, or chemicals (e.g. herbicides). Ensure that they are not exposed to any chemicals in their environment.
– After a mare has given birth, ensure that none of the placenta (after birth) remains inside.
– Prior to any treatment involving steroids or hormones, verify with your veterinarian that the doses do not pose a risk of laminitis.