In the equine foot, the outside part of the hoof is held onto the pedal bone (bone inside the hoof) by a sensitive, vascular structure called the lamellae. Laminitis is essentially inflammation and degeneration of this structure. In a normal horse, each time the horse walks their weight is dissipated through the lamellae onto the front of the hoof wall. In horses with laminitis, each time the horse walks the weight is projected onto the pedal bone and essentially onto the sole of the foot causing further lamellae breakdown and in severe cases, sinking of the pedal bone and potential protrusion of this bone through the sole of the hoof.
While the exact mechanism through which the lamellae break down is still debated, there is consensus on some of the causes including;
• Any type of systemic infection (septicaemia) or inflammation
This can result from:
* Viral/bacterial infection
* Respiratory disease
* Severe colitis/colic
* Carbohydrate overload on the hindgut following ingestion of excessive grain, fruit, bread of pasture causing rapid overgrowth of hindgut anaerobic streptococcal bacteria
* Snake bite
* Lameness in one or more feet
* Shifting weight between feet or rocking back on feet
* Wide based stance
* Spending large amounts of time lying down
* Bounding digital pulse and heat in the hoof wall
A diagnosis of laminitis is made by combining the above clinical signs with a thorough history and:
* Consistent pain response elicited with hoof testers over the pedal bone
* Radiographic changes (separation of the pedal bone from the hoof wall)
Treatment is targeted at limiting the progression, reversing the underlying cause and controlling pain. The exact nature of treatment depends on the cause, stage, severity and number of feet affected.
Prognosis depends on the degree of separation of the pedal bone from the hoof wall. Horses with mild to no separation may regain athletic function while those with severe rotation require euthanasia.
• Please remember there are a plethora of things that cause lameness in horses and not every lame horse has laminitis. If you are concerned, please contact one of our friendly staff.