Laminitis

What is laminitis?

Laminitis is an incredibly painful condition that affects the feet of ponies, horses and donkeys. It is inflammation of the laminae the small ‘finger-like’ structures that connect the hoof wall to the pedal bone, the main bone in the hoof.

Inflammation of the laminae leads to their breakdown, often resulting in rotation and sinking of the pedal bone. This rotation in some cases can be so severe that the pedal bone comes out of the bottom of the hoof. It is a serious condition which is often recurrent and can lead to euthanasia.

Clinical signs

Laminitis usually presents with lameness that affects two or more limbs. Horses and ponies will often shift their bodies backwards to take the weight off their painful toes. Lying down is a common symptom, which also allows weight to be taken off the feet.

Due to the inflammation in the feet, they will usually be hot and have increased digital pulses. Lameness is usually worse on hard ground and on the turn and there will often be weight shifting on different limbs.

Some early or mild cases will initially show as a shortening of their normal stride or what may be described as a “footy” short action. With long term laminitis or subclinical laminitis (no obvious lameness) the hooves will develop diverging hoof growth lines.

Causes

Laminitis is classified into three groups of underlying causes:

1. Endocrine (hormonal) causes (~90% of laminitis cases) – Cushing’s Disease (PPID) and Equine Metabolic Syndrome (EMS). Both of these conditions cause insulin dysregulation, which then causes laminitis
2. Weight overload of one leg due to injury of the opposite leg e.g. fracture
3. Severe whole body inflammation / sepsis e.g. Retained fetal membranes, diarrhoea, pneumonia, some colics

Diagnosis

A diagnosis of laminitis is usually based on clinical history and a clinical exam, with the typical symptoms listed above including pain on hoof testers.

Radiographs are very helpful to assess the degree of rotation and or sinking of the pedal bone, they are also helpful to help guide trimming and shoeing of the feet.

Treatment

Laminitis is a medical emergency and you should contact your vet if you suspect your horse or pony has laminitis. Below are some of the treatments your vet will advise:

• Pain relief: All horses and ponies need pain relief when suffering from laminitis, as it is a very painful condition. This is usually non-steroidal anti-inflammatories (such as phenylbutazone – so called ‘bute’, danilon or other similar medications) but other drugs can be given in addition if required.
• Box rest: Whilst a horse or pony has laminitis and painful feet, they should be box rested in a deep bedded stable to try to prevent further damage and pain. Your vet can help guide you as to when to start re-introducing exercise and turnout.
• Support and shoeing: support to the feet should be provided with all cases of laminitis, in milder cases this can be a deep bed throughout the stable. In other cases, additional sole support is needed e.g. putty, Styrofoam, lily pads and a variety of clogs. Specific remedial shoes can be used longer term to provide support.
• Dietary changes: Patients with laminitis should have a restricted low calorie diet of poor quality forage e.g. soaked hay. All high energy food sources e.g. hard feed and haylage should be removed. A low calorie balancer can be fed to provide essential vitamins, minerals and protein and should be fed if your horse is on a restricted diet longer-term.
• Ice: in the very acute stages of laminitis especially in patients with concurrent whole body inflammation or sepsis, ice / cold water treatment of a horse’s feet can help prevent and minimise laminitis.
• Treatment of underlying conditions: patients with underlying conditions, such as Cushings disease or Equine Metabolic Syndrome (EMS), must have these conditions treated. Without treatment of these underlying conditions it can be very difficult to resolve laminitis and recurrence is much higher.

Prevention

The chances of your horse, pony or donkey getting laminitis can be reduced in several ways:

• Ensure a healthy body weight is maintained and that your horse is not overweight
• Regular trimming to prevent long toes and ensure good foot balance
• Prompt diagnosis and treatment of underlying causes of laminitis, especially Cushing’s disease and Equine Metabolic disease