LAMINITIS         

 

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WHAT IS IT

 

Every day veterinarians across the country see hundreds of cases of laminitis, a painful disease which affects the horse's feet. What's especially alarming is that some cases are preventable. In fact, it may be that we are killing our horses with kindness.  Consider that a common cause of laminitis is overfeeding -- a management factor that is normally within our control.

 

Laminitis is a medical emergency which should be treated urgently to prevent 'founder'.  It is the inflammation of the sensitive laminae connecting the distal phalanx to the hoof wall and one of the commonest causes of lameness in ponies. The disease occurs when things go wrong within the structure of the hoof.  It is very painful for the animal.

The hoof becomes loosened from its attachment to the rest of the foot and, worse, the whole weight of the animal presses down on the sore area.  There is no human equivalent to laminitis, so it is hard for us to realise just how painful this disease is for a pony. However, think how sore a damaged fingernail can be when you knock it. Then imagine what it would be like if you had to support your bodyweight by balancing on sore fingernails!

 


CAUSES


Laminitis cannot be caught from other horses, and it rarely happens because of any foot problem. It develops because of toxins released elsewhere in the horse's body, which affect the circulation in its feet. There are several different sources of toxins, but by far the most frequent is the bowels - where toxins originate because of feeding too much protein.


Many pony breeds have changed a little over thousands of years. Their digestive systems evolved to deal with a sparse supply of relatively coarse and indigestible material - grass.  Ponies are not designed to cope with large amounts of lush protein-rich spring grass or concentrates.

 

THE SIGNS


Laminitis affects both front feet and may well affect all four of the horse's hooves.  The pony is in severe pain and usually refuses to stand up or walk. If he does stand, it is in a particular way - with his hind legs well under his body to supports its weight and with the front feet forward to leave as much weight on the heels as possible.  When he has to move, it is with a pottering action, walking on his heels. The feet feel warm to touch and the pony looks very sorry for him self.

 

The pony probably also has a temperature and a bounding pulse in the digital artery at the back of the pastern. A pony that has had laminitis for a long time is likely to have abnormal hooves - a "drooped" sole from the bone pressing down, and laminitic rings because of different hoof growth. The hoof wall may separate from the sole at the tow, with rotten horn in between, which is called a "seedy toe".  

 

Strictly, speaking laminitis is inflammation of the laminar corium, an area of soft tissue in the foot containing lots of nerves and blood vessels. The immediate effect of this inflammation is pain and limping.

 

More long term, damage to this part of the foot affects horn production for the remainder of the animal's life. This weakens the foot's structure and can contribute to the appearance of a number of foot problems, including white line disease and sole ulcers.  Horn is formed when cells from this area of soft tissue move slowly towards the outside of the foot, accumulating a hard protein structure called keratin.

 

 


TREATMENT


Unless you have experience, you should call in the vet to treat the pony without delay, before foot changes go to far.  First he will advise you to remove the cause of the trouble. This usually means taking the pony away from his grazing. It may also involve cutting out the concentrate ration and feeding hay and water only. Secondly he will give a painkilling injection as soon as possible. This works immediately, and he normally leaves more powders to continue pain relief for several days.  

 

Applying water from the hose may also be better to improve the circulation.  You need to relief the pain so the animal can walk. - Which stimulates the circulation in the feet. The pain becomes less as the pony moves. About ten minutes of leading at a walk, six times a day should be enough.  For longer-term treatment you will need both the vet and the farrier to correct the hoof problems.  

 

The sooner treatment begins, the better the chance for recovery. Treatment will depend on specific circumstances but may include the following:

  • Diagnosing and treating the primary problem (Laminitis is often due to a systemic or general problem elsewhere in the horse's body.)

  • Dietary restrictions

  • Treating with mineral oil, via a nasogastric tube, to purge the horse's digestive tract, especially if the horse has overeaten

  • Administering fluids if the horse is ill or dehydrated

  • Administering other drugs, such as antibiotics to fight infection; anti-endotoxins to reduce bacterial toxicity; anticoagulants and vasodilators to reduce blood pressure while improving blood flow to the feet (Corticosteroids are contraindicated in laminitis, as they can actually cause laminitis or exacerbate existing cases.)

  • Stabling the horse on soft ground, such as in sand or shavings (not black walnut), and encouraging the horse to lie down to reduce pressure on the weakened laminae

  • Opening and draining any abscesses which may develop

  • Cooperation between your veterinarian and the farrier (Techniques that may be helpful include corrective trimming, frog supports, and therapeutic shoes or pads.)

EMERGENCY TREATMENT

 

Part of an emergency treatment consist of relieving the weight bearing function of the (dorsal) hoofwall which sustains PIII through the affected laminae. This can be obtained by transferring weight-bearing function to the palmar aspects of the sole, including the bars, and to the entire frog, which are not affected by the laminar inflammation.  This all sounds rather technical, but in fact one easy and quick way of doing this is by applying a foot cast with extra support below the palmar structures.

 

Since PIII is not only suspended through the laminae to the hoofwall but also attached to its extensor tendon an the, much stronger, deep digital flexor tendon (DDFT), raising the heels and therefore releasing the pull of the DDFT can be useful in the acute phase. (Fig.1)

 

Therapeutic shoeing should make the horse more confortable, that is reduce pain and there fore the need for analgesics but also the pain stimulus for DDFT contracture. Nailing is often too painful and difficult because of hoof wall loss or instability. Laminitic and foundered horses can be grateful to the advent of glue on shoes. (Fig.6)  

 

 

For an excellent - medical emergency treatment overview of acute laminitis see "Medical and Surgical Treatment of Acute Laminitis in Horses" by F.Desbrosse, in European Farriers Journal nr. 71, page 18-43.  

 

 

SUMMARY  

 

The best way to deal with laminitis is preventing the causes under your control. Keep all grain stored securely out of the reach of horses. Introduce your horse to lush pasture gradually. Be aware that when a horse is ill, under stress or overweight, it is especially at risk. Consult your equine practitioner to formulate a good dietary plan. Provide good, routine health and hoof care. If you suspect laminitis, consider it a medical emergency: Notify your veterinarian immediately.

 

 

 

 

HORSE SANCTUARY UK LIMITED is a company with charitable objects Registered in England and Wales No. 4593172

 

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