Laminitis

Laminitis is a potentially agonising condition and a sudden flush of grass can increase the likelihood of an attack. Every case should be dealt with promptly and the condition should never be underestimated – in a recent study around one in five horses with laminitis were euthanased.

Normal foot	p3 Sinker	p3 Rotation

Causes of laminitis
Laminitis can be caused by the following:

• Excessive food intake: This ranges from the traditionally-susceptible overweight pony gorging itself on spring pasture, to a horse gaining access to the feed room and helping itself. This is the most common cause of laminitis seen.
• Toxins: Toxins released by bacteria during certain illnesses, such as uterine infections, often following a retained placenta, severe colic (or after colic surgery) and, less frequently, diarrhoea or respiratory disease.
• Trauma: Either in the form of repeated concussion from exercise on hard ground or as a result of over-enthusiastic hoof trimming.
• Stress: Either for a short period (head collar caught on an immovable object or a pony stuck in a ditch) or over long periods (close confinement while separated from other horses, or long journeys).
• Tumour: The presence of a benign pituitary tumour (usually in horses over 20 years old) which results in an increased circulation of natural steroids – Cushing's Disease.
• Drugs: Steroid induced laminitis is a recognised condition in all horses. Though the risk is small it is still a recognised risk for any steroid injection.

Excessive Food Intake – The most common cause of laminitis
The dietary launchpad for laminitis is the overflow of starch or sugar in to the large intestine, resulting in an unhealthy disruption to the ongoing fermentation of fibre there. Opinions are still divided as to the process which lead to inflammation in the hooves, but there is no doubt that it does.

Low-forage, high-starch diets can create these dangerous conditions, as can a huge sugar (including fructans) overload from sudden access to rich new grazing. With the current good weather a sudden flush of new grass can easily lead to this overload.

Recognising laminitis

Obvious signs of acute laminitis, where the horse is in pain but structural changes have not yet occurred in the foot, include:

• Hooves that feel hot and feet are painful with pressure to the sole
• An obvious or pounding digital pulse (found just below the level of the fetlock) and in severe cases, this digital pulse will be pounding on all four feet.
• A tendency for the horse to stand with its legs stretched forward, while leaning backward, to ease the weight onto its heels away from the painful inflammed laminae in its feet
• Prolonged periods lying down and reluctance to stand or move
• Mild cases will constantly shift their weight from foot to foot as they try to find the least painful way of weight-bearing
• The pain of laminitis may also cause an increased pulse and respiratory rate

Chronic cases, where the condition has existed for some time or repeated bouts can result in the pedal bone shifting within the hoof structure, resulting in varying signs of discomfort. Along with the above signs seen with acute laminitis, horses with structural changes as a results of laminitis may also present as:

• Intermittently lame, particularly on rough ground
• Footsore and/or bruising evident when the feet are trimmed
• Repeated pus in the foot
• Odd-shaped feet including rings on the hoof wall, long toes, dropped soles, wide white lines and flat feet

Acute laminitis

This is the intial stage of the condition when the horse or pony is uncomfortable and showing signs of lameness, but typically major damage has not yet happened within the hoof. The laminae that attach the pedal bone to the hoof capsule have become inflammed and the act of wieght bearing through these laminae is painful to the horse or pony. The chances of recovery are maximised if treatment is intiated as early as possible.

Chronic laminitis

Repeated bouts or continued laminitis results in a chronic condition where prolonged damage to the laminae in the hoof capsule can lead to rotation or sinking of the pedal bone. These conditions are much harder to treat and will require good comminication between your vet and farrier.


What should you do if you think your horse or pony has laminitis?

Laminitis, whether mild or severe, must be treated urgently to prevent long term damage and veterinary advice should be sought immediately. Do not force your horse to stand or walk. Stable the horse on deep bedding (at least 30-40cm), such as shavings or cardboard which moulds to the shape of the horse's hooves until the vet arrives.

In severe cases your horse may be unable to move. They may be panting, sweating and leaning back on their heels. In the worst cases, they will lie down and be unable to stand – this condition can be confused with colic or tying up

Treatment

Non-steroidal anti-inflammatories (commonly Bute) is typically requried for pain relief and Acepromazine (ACP) to encourage blood flow to the foot. Depending on the severity of the laminitis other treatments may also be advocated.

Personally I prefer to remove any shoes and apply frog supports for short term pain relief until in conjunction with the farrier the feet are trimmed appropriately. Often to aid accurate trimming radiographs need to be taken to ascertain the location of the pedal bone in relation to the external hoof wall and sole. Good communication between client, farrier and vet are essential to ensuring a speedy recovery as all three have vital roles to play in the recovery period.

All horses with laminitis should be box-rested, ideally on non-edible bedding. A deep bed (30-40cm) of shavings or cardboard is best. This acts by providing even pressure across the whole of the sole and frog rather than just loading the hoof wall. Affected horses should be allowed to lie down and rest their feet. Total box rest is important to ensure adequate movement restriction and should continue for as long as directed by your vet.

Correct feeding is essential during this period. Diet needs to be adjusted to ensure that the horse's weight is controlled whilst minimising the likelyhood of prolonging the disease process. It is crucial that any overweight laminitic horse loses weight, but this must be a gradual process. As each case is individual it is best to consult with your vet as to what diet is best suited to your own horse during this recovery period. In general terms high carbohydrate feeds are to be avoided and roughage feeds should be fed little and often to allow a gradual intake of food. High fibre, low energy hay is ideal as a roughage source for horses or ponies with laminitis.
 
Preventative measures

As with all diseases prevention is better than a cure. Any dietary changes should be made gradually: horses can cope with starch and sugar in the diet as long as it is moderate amounts and not introduced too quickly.

A change in forage to one that is less palatable or even to a new batch that is much wetter or less palatable can lead to an unseen drop in fibre intake, bringing a horse closer to the danger zone. 

While fat ponies enjoying the spring grass are "typical" laminitis sufferers, any horse that is carrying too much weight or being fed an inappropriate diet can suffer a sudden attack of laminitis.
 
Chronic Laminitis resulting in strucutral changes to the hoof

Chronic laminitis can lead to rotation of the capsule around the pedal bone or in more severe cases dropping of the pedal bone within the capsule. The recovery and survival rates of laminitics depend on how advanced the condition is and by what degree the rotation or sinking has occurred. Horses or ponies that have progressed to sinking have a very poor prognosis, a recent study found that only around 20% at best survived. These cases definitely require good team work between farrier, vet and owner as often recovery periods can be prolonged, difficult and may still sometimes result in a poor outcome.

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