Understanding Laminitis

An introduction to Laminitis

What is laminitis?

Equine laminitis is a painful condition of the feet affecting horses and ponies. It is the most common cause of lameness in the UK. The lameness ranges from being barely noticeable to severe. Laminitis involves inflammation in the sensitive tissues of the foot (laminae). These tissues connect the lowest bone within the hoof (pedal bone) to the hoof wall. As the condition develops, this connection starts to weaken, causing the pedal bone to rotate and point towards the sole (sinking). There are two types of laminitis: acute and chronic.

Acute laminitis

Early stages of the condition
Considered a vet emergency
Clinical signs present but pedal bone hasn’t moved
Can be treated to prevent it becoming chronic

Chronic laminitis

Later stages of the condition
Pedal bone has moved within the hoof
Ongoing foot problems are more likely such as lameness and foot abscesses

What causes laminitis?

Laminitis arises when the blood flow to the foot is interrupted. This results in certain areas not receiving sufficient blood but blood carries oxygen and vital nutrients. Therefore, cells in the foot become damaged which causes inflammation and pain.

Laminitis is a complex condition with several possible causes. About 90% of laminitis cases are caused by underlying hormonal (endocrine) disease ‐ mainly Cushing’s Disease and equine metabolic syndrome (EMS). The remaining 10% may be caused by:

carbohydrate overload eg if your horse gets into the feed-room;
toxaemia, due to toxins released by bacteria during some illnesses such as colic, diarrhoea, liver or respiratory disease, or from a retained placenta after foaling;
concussion, perhaps due to working on hard surfaces;
excessive weight bearing, when lameness in one limb causes the horse to carry too much weight on other limbs.

What are the clinical signs of laminitis?

Laminitis can affect all four feet, but most commonly affects the front. The typical stance is with the affected horse standing with his hind-legs well underneath his body and leaning back to take weight of his front toes. He may also have hot feet with a strong (digital) pulse felt at the back of his fetlock. Other possible indicators are: signs of pain such as reluctance to move, facial tension, and a lack of interest in his surroundings; general stiffness; or weight shifting while at rest. He may also have a ‘pottery’ walk caused by placing the heel down before the toe, or lameness that is exaggerated on a hard surface.

How can I prevent laminitis?

Laminitis may be prevented by ensuring your horse is of correct weight and body condition score. Feed him an appropriate diet with sufficient exercise to prevent weight increases. Latest research suggests avoiding diets containing too much sugar (including molasses) which affects insulin levels. Monitor for underlying metabolic conditions and causes of laminitis, such as Cushing’s Disease and EMS. For horses with a past history of laminitis, it is essential that you follow the advice from your vet, farrier and nutritionist to manage your horse effectively.

How is laminitis treated?

There is no cure for laminitis, but early treatment and management will improve the chances of recovery. Your vet should be called early on in all cases of laminitis. Box rest is necessary to minimise movement and prevent further damage until your horse becomes sound. Pain‐relieving medication can be administered, such as phenylbutazone (bute). X‐rays will check for pedal bone movement and daily monitoring of foot temperature and digital pulse is advisable. Feet may be trimmed appropriately or shod with special shoes to alleviate pressure and prevent further damage. Try to eliminate recurrence of laminitis by reducing grass intake and feeding an appropriate diet, read more about feeding the laminitis prone horse.

Did you know? Restricting access to fresh grass can have a negative impact on the level of vitamin C in horse's systems as they use grass to generate vitamin C. Supplementing vitamin C in the diet is therefore beneficial for horses and ponies on a restricted grass diet.

What is the prognosis of laminitis?

Horses can recover from episodes of acute laminitis and, if treated promptly and effectively, chronic laminitis can be avoided. It is essential to act quickly and work alongside your vet, farrier and nutritionist to improve the prognosis. Hoof damage may cause ongoing problems which need to be managed accordingly. Horses that have suffered one attack of laminitis are more susceptible to suffering laminitis in the future, so careful monitoring and good management is key.

With a timely diagnosis, prompt and appropriate treatment, and effective management, it is possible for horses to return to their former use and have a good quality of life.

Thank you to vet, Rachel Harrison-Osborne of Wendover Heights Veterinary Centre, for her input to this article.