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Equine Laminitis
by
Anthony Coyne MVB MRCVS
Animal Herb Company

Laminitis a devastating and common ailment of the horse recognized for centuries but even to this day we struggle with its treatment and prevention.

In this issue we look at this condition and examine its causes, manifestations and we will look at how we may help prevent its occurrence.

What is Laminitis?
Laminitis is a very painful condition of the foot. Basically it is a failure of the attachment of the pedal bone and the inner hoof wall. The pedal bone is attached to the hoof wall by two interlocking layers of laminae (strong connecting tissues) and when these tissues for whatever reason get inflamed or the blood supply is disturbed the attachment between the laminae fail. This results in a tearing of the pedal bone away from the hoof wall and due to the strong pull of the deep digital flexor tendon a consequent rotation of the pedal bone within the hoof. This cascade of events can result in varying degrees of change depending on the inciting cause with worst cases involving the pedal bone rotating so much as to have its tip penetrate the solar surface or the attachment tearing away not only at the front of the foot but all the way around allowing the pedal bone to sink within the hoof.

What are the signs?
Laminitis can occur in two forms acute and chronic. In acute cases the onset of signs is rapid and can be severe. In chronic cases the symptoms can develop over time or may result from previous acute attacks that fail to heal completely.

Acute cases:
Extreme lameness and unwillingness to move forward usually present in the front feet but can be present in all four. Characteristic stance with the forelimbs extended in front with the hind limbs brought forward in an attempt to shift the weight back off the front limbs, as they are usually worst affected. Heat in the feet with a pronounced increase in the digital pulses. The horse may be unwilling to lift either front foot off the ground. Painful response when pressure is applied to the sole in front of the frog. Swelling at the coronet may be present.

Chronic cases:
These cases will show most of the acute signs but not as pronounced. The horse may appear stiff. Rings in the hoof wall may be present with the rings being wider at the heel than at the toe. Bruising of the soles may be present. On examination of the sole it may appear to have a flat or dropped appearance. Some ponies that suffer from chronic laminitis often have a large thickened neck crest. "Seedy Toe" may be present where there is widening of the white line at the toe with possible secondary infection.

What are the causes of laminitis?
Many "triggers" of laminitis have been identified. The most common cause is the sudden ingestion of an excessive amount of soluble carbohydrates. This is where the horse engorges itself on a lush pasture or breaks into the feed shed and helps itself to the grain. Obese or overweight horses that have little exercise are very vulnerable. Excessive concussion on a hard surface has also been implicated. Laminitis can be a rapid sequel to toxic conditions such as retained placenta or Salmonella enteritis. Older horses that develop Cushing's disease, a hormonal disorder have an increased susceptibility to the condition. Hypothyroidism can also be a predisposing factor in its development. Excessive weight bearing in one limb due to severe lameness in the other may result in the good limb developing laminitis. Therapies using corticosteroids can cause laminitis.

If you suspect laminitis what should you do?
When your horse first suffers a laminitis attack, it is very important to respond quickly. Early signs of laminitis can quickly escalate to become quite serious. If you suspect laminitis contact your veterinarian immediately. Put your horse in a deep-bedded stable so that it has a good cushion under its feet. It is not advisable to walk your horse as the laminae are torn, fragile and you risk doing further damage. Your vet will then assess the case and investigate if there is any underlying cause that needs immediate treatment such as a retained placenta. If grain overload is involved your vet may administer liquid paraffin. Initially the focus will be on pain relief as laminitis is a very painful condition. Various other anti-toxic drugs will be administered and drugs that improve the circulation to the feet. Radiographs may be taken to assess if rotation has occurred. Often the veterinary surgeon will liaise with the farrier and special shoes to support the foot will be applied. In the recovery period it may be necessary to repeat X-rays and reassess shoeing at later stages. Recovery from laminitis is a slow process and it should be considered in months and years not days or weeks. Patience and diligent aftercare are therefore very important in the treatment. Cases that do recover may be prone to further laminitic episodes. It must also be said that although most cases are usually treatable, laminitis has the potential to result in permanent severe lameness making euthanasia the only option.

When can the horse be ridden again?
Most horses that have been treated for laminitis can be ridden again. After the pain is gone you will be dealing with a very delicate foot. When you can start riding again depends on how severe the symptoms were and how good the treatment response has been. If there is any rotation it will take at least eight months for the damaged areas to grow out. If no rotation has occurred two months rest and correction of the predisposing factors should be considered. Your vet should direct you when it is safe to start riding again. Also once a horse has laminitis they are prone to recurrences so it is important to watch closely for the signs of laminitis and stop riding if you are suspicious.

How can you prevent laminitis?
Weight control is very important in the overweight pony. Restrict access to lush pastures. It should be possible to fence the pony into a small area of the paddock. Make sure feed sheds are closed securely. Riding your horse daily is very important. Regular visits from your farrier to maintain a well-balanced foot. Nutritional supplements such as biotin supplements should be given if the hoof quality is poor. A thorough knowledge of the causes of laminitis is important so you can identify the risk factors early and thus avoid them.

Herbal supplements as an aid to treating laminitis. Many owners have found tremendous benefit in using herbal supplements in the recovery of laminitic cases. Anicripple from the Animal Herb Company is one I use regularly and find it an excellent adjunct to therapy. In Chinese medical understanding of laminitis they see stagnation of blood and energy in the feet, blockage of the channels and toxicity as being important in the development of the condition. Herbs such as Lonicera and Forysthia are included in the formula, which have anti-infection and anti-toxic properties. Clematis that opens the channels, Carthamus and Dang Kuei that helps nourish and move the blood. Also pain-killing herbs are included. Thus it can be a powerful remedy with many properties that can aid healing. With recognition of the symptoms and causes of laminitis and prompt action when you suspect it, the devastating effects of this horrible condition should be minimized.

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