This article has been published previously by Equestrian Life. To see what's in our latest magazine, click here.

Laminitis is a common issue.

© Andrew Bowe

by: David T.Wood BVSc.MRCVS.

Part 1.

Laminitis is like one of those terrible anti personnel mines which aim to cripple rather than kill their victims, though many afflicted horses will eventually be euthanized because of it, even though they may recover somewhat from the acute phase. Like a land mine it can strike suddenly without warning and with disastrous results. Unlike a land mine however, Laminitis has a nasty habit of recurring in the survivors which may need months or years of rehabilitative care to become sound again, and many never do.

As the name suggests Laminitis is an inflammation of the sensitive laminae which attach to the horny insensitive laminae inside the hoof, like interlocking leaves holding the hoof wall and sole onto the underlying structures of the foot. The inflammation is merely a symptom of varied underlying disease processes with a range of associated risk factors. One of the many problems with this disease is that by the time the usual signs of inflammation, swelling, pain, and increased blood flow show themselves, the damage to the delicate laminar membranes may already be severe, limiting the possibility of effective treatment.

Recognition

Early recognition of the signs is of paramount importance in determining the eventual outcome, though we now know that the disease may have been progressing without obvious signs for hours or even days before showing itself.

The laminitic horse shows some or all of the following signs:

• A shortened stride at the walk and / or a reluctance to turn
• Increased digital pulse, often described as “Bounding” – owners should get to know how to take the pulse at the back of the pastern and what it feels like normally.
• Feet that are warm or hot to the touch, especially the front feet. Comparing the front and back feet may help in determining this.
• Shifting weight from one front foot to the other
• The classic laminitis stance has the front feet extended forward or “camped out” and the hind feet placed further under the body than normal – the horse it trying to place more of its weight over the less painful hind feet.
• A pained or anxious facial expression.
• Increased pulse and / or respiratory rate at rest. Elevated rectal temperature.

By the time these signs have developed structural damage to the foot may have already happened. If in doubt then veterinary help should be sought immediately and urgently – far better a false alarm than a crippled horse.

Evaluation

Veterinarians may use the “Obel” system to grade the severity of the laminitis related pain and help determine treatment options. The system uses the four categories reproduced below:

• Grade I Horses shift weight from one foot to the other or incessantly lift feet. Lameness isn't evident at a walk, but at the trot horses will have a shortened stride.
• Grade II Horses move willingly at a walk and trot, but they do so with a noticeably shortened and stabbing stride. A foot can be lifted off the ground without difficulty.
• Grade III Horses move reluctantly and resist attempts to lift affected or contra lateral feet.
• Grade IV Horses express marked reluctance or absolute refusal to move.

In addition to this assessment a history is taken and a clinical examination is made to try to determine any underlying causes for the attack with a view to eliminating them if possible.

The main diagnostic tool used is radiography. This enables the vet to determine whether or not the coffin bone inside the hoof has separated from the hoof wall and rotated, and if so the degree of rotation which is an important predictor of the likely prognosis. In mild cases there may be little or none. In the severest cases the coffin bone may sink right into the sole of the foot and penetrate it with dire consequences for the horse.

Typically the front feet are more affected than the hind due to the uneven weight distribution of the horse’s body with around 65% of its weight being borne in front. All feet may be affected however.

Join us tomorrow as we look at Part 2 - Underlying Causes

David T.Wood BVSc.MRCVS.

David is a veterinary surgeon with 35 years equine experience gained in several countries. For the past 20 years he has pursued a special interest in equine nutrition and currently acts as veterinary and technical advisor to Horsepower.

This article has been published previously by Equestrian Life. To see what's in our latest magazine, click here.

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