Laminitis in Horses

Hoof pulmonary inflammation is a type of osteoarthritis, an excessive wear of the back of the radius bone and the deep flexor tendon that runs over it. The excessive wear and tear of the flexor tendon rubbing directly against the bone causes chronic inflammation, which is painful and, if the cause of the wear and tear is not corrected, eventually leads to the destruction of the hoof patella.

A horse with inflammation of the calcaneum walks lame, does not dare to put its foot down and often shows a shortened stride. The leg is not thick and warm, and resting the horse will make it better for a while, after which the horse will soon be lame again. There is often a history of more frequent stumbling, intermittent limping, improvement after rest and pronounced stiffness one day after work. Usually, both front legs are affected, one worse than the other. Gradually, the shape of the foot changes so that in chronic cases, the foot becomes narrow and steep. X-rays can then indicate the internal appearance of the hoof and the extent of the inflammation.

Possible causes of laminitis.

• Hereditary factor: this inherits narrow and steep hooves. Narrow hooves have a smaller surface area, so pressure per unit area is greater, and there is a greater risk of bruising. These bruises can be the cause of degenerative changes in the hoof.
• Trauma: horses that are subjected to repeated trauma are at greater risk of developing laminitis. Especially with horses that have to work on hard and uneven ground, horses that have to jump a lot or horses that work very hard at high speeds.
• Trimming: poor trimming and shoeing of hooves creates or accentuates stance abnormalities. For example, horses with steep feet often have their heels shortened by a considerable amount. This results in a position whereby the deep flexor tendon exerts greater pressure on the radius and a broken hoof-leg axis results.
• Low shins: Horses with low shins are also indicated as a factor increasing the risk of developing laminitis. This position deviation results in a rearward broken hoof-leg axis, which causes a permanent stretching of the hoof joint and greater forces on the LSC (ligamentum sesamoidea collateralia) and the deep flexor tendon. A third consequence is that the toe always comes into contact with the ground first.
• Age: some horses that have been in heavy work for many years develop an irregular or poor blood supply to the radius bone. This causes demineralisation of the radius bone.
• Economic factor: Many horses are broken in at a very early age and then demand a lot from such a young horse just to make a profit. The horse must be fully grown before high demands can be made of it. Too little exercise can also be a factor. A horse is a walking animal. So 23 hours in the stable and 1 hour of hard work can never be good.