Laminitis is a painful condition involving inflammation of the laminae. In severe cases the laminae become inflamed all around the hoof resulting in uniform separation, when the limb is loaded the whole pedal bone then ‘sinks’ within the hoof. The prognosis following rotation is much worse; radiographs are useful to identify what had actually happened. Here Ed Lyall, BVetMed, CertEM (StudMed), MRCVS of the Sussex Equine Hospital explains more.
There are several reasons why laminitis occurs and it is important to identify the cause so treatment can be carried out accordingly:
1. Equine metabolic syndrome (EMS) which is effectively a form of insulin resistance.
2. Cushing’s disease which many older horses and ponies are now diagnosed with.
3. Some form of sepsis or infection that result in the release of toxins within the body, such as colitis, colic surgery or retention of a portion of the placenta after foaling. Grain overload also falls into this category as the change in diet results in abnormal toxin producing bacteria colonising the gut.
4. Excessive loading of one limb due to injury to the opposite limb.
5. Excessive exercise on hard ground.
Laminitis affects the front limbs more commonly that the back limbs, but one foot can be affected or even just the hind feet. The typical signs of laminitis include:
1. Abnormal stance – usually with the weight rocked back onto the heels and toes out in front off-loading the weight from the more painful toe region.
2. Often cases look very awkward on their hindlimbs, but this is a result of more load being taken by the back end.
3. Walk is reluctant with a toe slapping gait, where the heel is loaded before the toe. There will often be stiff, stilted gait when turning sharply on a hard surface.
4. Often soft footing will be favoured by the patient. Severe cases will lie down and be reluctant to get up.
5. From a clinical point of view the hoof capsule may be hot with a strong pulse palpable in the palmar digital arteries at the back of the fetlock and there will be a pain response on hoof tester pressure in the toe region.
If laminitis is suspected, the first thing to do is make sure there is a deep soft bed, administer pain killers in the form of phenylbutazone if available and then contact a vet for assistance. Laminitis is in many cases an emergency.
This will comprise of the following:
1. Removal of shoes, shortening the toe to reduce the rotating effect of the deep digital flexor tendon.
2. Some form of frog support will then need to be applied, and this is to off load the weight from the painful hoof wall.
3. If we know there has been a toxic episode then icing the feet can reduce the blood supply and prevent further toxins from reaching and damaging the laminae further.
4. Over the years many products have been tried to affect blood flow to the laminae, such as ACP and an ointment form of trinitroglycerine.
5. Phenylbutazone or a derivative is the main pain relief used.
6. Appropriate levels of exercise depending on response to therapy, initially strict rest, then more comfortable turn out in a small paddock may be allowed.
7. Once the initial laminitic incident is under control, then there are a multitude of types of shoes that can be applied to the feet from egg and heart bar shoes, reverse shoes, four point shoes with rails to clogs. The clogs have saved many horses’ lives recently and again are my favoured transition from strap on pads to more normal shoes.
To find out more about laminitis and other clinical conditions visit www.sussexequinehospital.co.uk