Laminitis – Causes, Symptoms & Treatment

Laminitis is a condition that affects the horse’s feet, causing pain and lameness.

What Is Laminitis?

People often imagine that laminitis (meaning inflammation of the laminae that form the junction between the hoof wall and the pedal bone) is a disease of the overweight pony However, there are nevertheless a number of trigger factors for laminitis, and the disease can be seen in all types of horse. Laminitis can result from obesity, a sudden overload of starch or carbohydrate (usually following accidental access to the feed store), and it can be a consequence of Cushing’s disease. Other factors include excessive concussion on hard ground, overgrown feet with long toes, endotoxaemia (a release of toxins into the blood) following colic or endometritis, cortico-steroid medication, stress, and increased loading of one foot when another is injured. In addition, grass alone can induce laminitis, particularly in spring-time conditions of cold nights and sunny days when fructan levels are high.

Symptoms Of Laminitis

The condition typically involves pain in both front feet, or at worst, all four feet, with a characteristic shortened ‘pottery’ gait that is particularly evident on the inside leg as the horse or pony is turned. The affected feet usually feel warm or hot to the touch, and a strong pulse may be felt at the heels, indicating inflammation. The application of hoof testers across the sole normally elicits a painful response, and it may be hard to lift any of the feet since increased weight-bearing on the others is resented. In severe and catastrophic cases the pedal bone loosens within the hoof, and a dip may be felt at the coronary band and a bulge seen in the sole due to founder (the sinking or rotation of the pedal bone). 

In a normal, healthy horse, the pedal bone (distal phalanx) is held securely in position within the hoof capsule by a complicated arrangement of interdigitating laminae. On the inner surface of the hoof wall, approximately 600 leaf-like projections – the insensitive laminae – interdigitate with the sensitive laminae on the surface of the pedal bone. Each of these laminae has 100-200 microscopic secondary

laminae which further increase the surface area for attachment. Laminitis means inflammation of the laminae and when it occurs this attachment is disrupted and the laminae tear apart. The breakdown occurs at the innermost layer of the hoof wall, known as the basement membrane. Unless immediate steps are taken to halt the progress of the disease, the weight of the horse pushing down plus the upward pull of the deep digital flexor tendon on the pedal bone and the mechanical forces of movement may cause the pedal bone to rotate and/or sink within the foot. The sensitive tissue that produces the horn is damaged and distorted. Important arteries and veins are crushed, together with the soft tissues and this leads to severe and often unrelenting foot pain.The pedal bone may prolapse through the sole of the foot.

The disease can be divided into 3 stages:

1. The Developmental Phase

This is the time when changes in the laminae begin but the horse does not yet experience foot pain.

2. The Acute Phase

This starts as soon as the pain begins and continues until the pedal bone starts to move within the hoof capsule.

3. The Chronic Phase

This includes all the possible subsequent outcomes from mild ongoing lameness to severe pain and penetration of the pedal bone through the sole of the foot.

The important thing to remember is that by the time the horse or pony is showing signs of lameness, damage has already occurred within the laminae and prompt action should be taken to minimize the progress of the disease.

Laminitis Causes

Although our understanding of the disease is increasing all the time and a great deal of research is being carried out, the exact sequence of events is still unclear. There are 3 proposed mechanisms.

1. Changes Of The Blood Flow To And From The Foot

Originally, laminitis was considered to occur owing to a reduction of the blood supply to the sensitive laminae as a result of constriction of the blood vessels and an increased tendency for clotting. This causes the tissues to die due to receiving inadequate oxygen and nutrients to meet their needs. It is now thought to be rather more complicated than this and a variety of changes occur within the foot that may contribute to the development of laminitis.

2. Activation Of Enzymes

Another theory is that the basement membrane between the hoof wall and the pedal bone is destroyed by enzymes called metalloproteinases (MMPs). In the normal hoof, controlled activity of these enzymes allows the horn of the hoof wall to grow downwards. It is thought that certain ‘trigger factors’ cause these enzymes to become overactive and destroy the attachment altogether. As this occurs, the capillaries Within the laminae are destroyed so the blood is unable to perfuse the foot. The blood is shunted from small arteries supplying the foot directly to the veins draining it. The resistance to flow through the damaged capillary beds accounts for the bounding digital pulse.

3. Traumatic and Mechanical Factors Experienced During Exercise & Weight Bearing

These factors must play a part in cases where laminitis develops in a limb that is taking most of the weight owing to severe lameness in the opposite limb. They probably play a part in all cases of laminitis once they have been initiated by either (1) or (2) above.

It is possible that all of these factors are involved in the development of laminitis.

Laminitis Trigger Factors

The exact nature of the trigger factors is still not clear. If a horse eats too much carbohydrate (e.g. lush grass containing lots of sugars), the capacity of the small intestine to digest it is exceeded and it spills over into the large intestine. Here it is rapidly fermented by bacteria including Lactobacillus spp and Streptococcus bovis which produce lactic acid. The proliferation of these bacteria and the increased acidity upsets the normal balance of micro-organisms in the hind gut. Some of the normal gut bacteria die and release endotoxins (poisons that are part of the bacterial cell membrane and are harmless until released when the bacteria die), while the S. bovis may release exotoxins (poisons released by the live bacteria). A combination of increased gut permeability (leakiness) due to the acidity and the release of chemicals by the bacteria may result in damaging trigger factors entering the circulation and reaching the laminae.

One theory is that chemicals known as ‘amines’ produced by lactobacilli and S. bovis in an acidic environment pass from the hind gut into the circulation where they cause constriction of the blood vessels entering or leaving the feet.This leads to painful oedema and laminar damage due to the capillary beds being starved of oxygen and nutrients.

Whatever the trigger, however, the laminae need to be exposed to it for a period of time before laminitis occurs. Some researchers consider that the blood vessels to the feet are dilated (open) rather than constricted during the developmental stage of larninitis. This is supported by the fact that cold therapy applied to the feet can actually prevent the development of laminitis in some situations.The situation is rather confusing and more research needs to be carried out before we fully understand this disease process.

Predisposing Factors

A number of different predisposing factors are known to lead to the development of laminitis. Animals that have suffered previous attacks are particularly susceptible.

Access To Lush Grass

In the process of photosynthesis, plants use energy from the sunlight to manufacture sugars from carbon dioxide and water. Many grasses produce and store high levels of carbohydrates called fructans. Fructans are used by plants as an energy source for growing and metabolism. These build up to high levels during the day when photosynthesis occurs. In the spring and autumn when the temperature is often cool but there are long hours of bright sunshine, fructans may accumulate to dangerously high levels. This is because cold temperatures cause growth and metabolism to slow down so the fructans are not used up by the plant. It has been demonstrated experimentally that fructans eaten in large enough quantities trigger laminitis. The horse does not have digestive enzymes to break down the fructans in the small intestine so they pass through the small intestine undigested and into the hind gut of the horse. Here they are fermented by bacteria including lactobacilli and Streptococcus bovis and the sequence of events discussed above may lead to laminitis.

Grain Overload

If a horse or pony is overfed or breaks into a feed store and eats a large amount of concentrates, the carbohydrate which is normally digested in the small intestine, spills over into the large intestine. Here it is rapidly fermented by the lactobacilli and Streptococcus bovis, producing large amounts of lactic acid.

Obese Animals

Obese animals are particularly susceptible.The combination of excessive rations and limited exercise causes horses to deposit large amounts of fat on the crest of the neck, over the shoulders and loins, at the head of the tail and inside the abdomen.When large deposits of fat build up within the horse’s abdomen, these begin to secrete hormones and cortisol which alter the horse’s metabolism. Affected horses and ponies have high blood levels of insulin and glucose even after fasting. They become resistant to insulin which is secreted by the pancreas. Insulin normally lowers the blood sugar by encouraging its uptake into tissues such as muscle and the liver. Insulin resistance is also associated with reduced blood supply to the feet, possibly due to the effects of increased levels of cortisol and glucose on the blood vessels. This condition is sometimes known as obesity dependent laminitis (ODL), equine metabolic syndrome or peripheral Cushing’s disease. Ponies and cobs are particularly susceptible. Unfortunately, the disease is self-perpetuating as the altered metabolism means that these animals put on weight with low calorie intakes that would not maintain a normal animal.

Infection

Any severe infection leading to toxaemia can result in laminitis, e.g. endometritis due to retained placenta, a serious colic, gut inflammation, diarrhoea, pneumonia, pleurisy.

Toxins

Toxins from bacteria, fungi, ingested plants or chemicals may lead to laminitis.

Weight

Excessive weight-bearing on one limb, e.g. due to a severe strain or fracture of the opposite limb, can lead to the development of laminitis in the uninjured, supporting leg. The pedal bone in these animals often sinks rather than rotates.

Corticosteroids

Administration of corticosteroids can cause laminitis in some animals. This sometimes happens following systemic treatment for skin disease or local injection into a joint. The mechanisms by which corticosteroids cause laminitis are not fully understood. They may increase the permeability of the gut, cause contraction of the blood vessels supplying the feet, affect the action of insulin or have a direct effect on the laminae of the feet.

Cushing’s Disease

Animals affected by this disease have high circulating levels of cortisol, glucose and insulin and are prone to developing laminitis, especially in the autumn. The hormone imbalance upsets the glucose uptake by the laminae. The laminae need glucose for their metabolism and without treatment horses with Cushing’s disease eventually develop laminitis.

Stress

Stress, e. g. frequent travelling of overweight show animals, being sold or the loss of a companion, can precipitate an attack of laminitis. Chronic stress increases circulating cortisol and adrenaline. Glucose consumption in the skin and feet is reduced so that the vital organs (heart, brain and lungs) receive it preferentially. Sustained reduction of glucose supply to the feet is harmful.

Concussion

Concussion from too much work on hard going can cause laminitis as a result of mechanical and traumatic stresses on the laminae.

Kidney Or Liver Disease

Chronic liver or kidney disease can predispose to laminitis because these organs become less efficient at breaking down and eliminating toxins.

Signs Of Laminitis

Any number from one to all four feet may be involved. However, the two front feet are most commonly affected.

Stance

Many laminitic animals develop a characteristic stance. The forelimbs are extended forwards and most of the weight is taken on the heels to relieve the pressure at the toe. The hind limbs may be positioned forwards under the body so they can take more of the horse’s weight.When all four feet are involved, the horse may spend long periods of time lying down. In these animals the feet are often positioned close together under the body when they stand.

Reluctance to walk and variable degrees of lameness

Affected horses and ponies are often extremely reluctant to move.When they do, they bring the hind limbs well forward under the body and land carefully on the heels of the front feet, so the gait is very stilted or ‘pottery’. They sometimes appear to lean backwards and the lameness is often much worse on turning. It is also accentuated on hard or uneven ground.Very mild cases may appear slightly stiff rather than lame or the lameness may only be observed on uneven ground or when the animal is turning.

Frequent shifting of weight from one foot to another

If one observes these animals at rest they frequently shift their weight between the feet in an attempt to relieve the constant discomfort. They may resist or refuse to lift a foot when asked because of the increased discomfort of taking more weight on the opposite limb.

Increased or bounding digital pulses

If the digital pulse is taken at the point where the digital artery crosses the sesamoid bones, it is often stronger than normal and described as ‘bounding’.

Reaction to hoof testers

  • Most horses and ponies with laminitis will flinch when hoof testers are applied to the sole in front of the point of the frog.
  • If the pain is very severe, the pulse and respiration rates increase and some animals have a temperature. They may seem very anxious and tremble and sweat.
  • Heat may be felt in the hoof wall during the acute stage of the disease.
  • Coronary band depression

An abnormal depression may be palpated on the coronary band at the front of the foot if the pedal bone has started to move. Palpation may cause some discomfort in the early stages. If the bone completely sinks, the depression will extend the whole length of the coronet.

  • A coronary band discharge of serum may occur. In severe cases, haemorrhage and serum from the inflamed laminae may build up sufficient pressure within the foot to escape at the coronary band.

Change in hoof wall conformation

As a result of recent studies, our understanding of the reasons why the hoof wall becomes deformed has increased. Originally it was thought that when the pedal bone rotates, its extensor process compresses the horn-producing tissues of the coronet at the front of the foot. This slows down the rate of new horn production at the toe. The result is laminitic growth rings which are wider at the heel than the toe.The hoof changes shape, developing high heels and a long toe with a concave anterior hoof wall.Another theory suggests that the change in growth rate of the hoof wall begins in the developmental stage of laminitis, before the pain begins. A faster growth rate at the heel causes the horn tubules to be distorted forwards. This causes distortion of the sensitive laminae, resulting in pain. The forward distortion of the hoof capsule results in the anterior hoof wall being lifted away from the underlying sensitive laminae starting closest to the ground and gradually working upwards. The result is a concave anterior hoof wall. It is suggested that the trigger factors initiating laminitis also trigger the faster growth rate of the hoof wall at the heels and that the pain of the acute stage of laminitis is due to the distortion of the sensitive laminae which occurs before any changes can be seen in the actual appearance of the hoof wall. The ‘dorsal wall lifting’ theory proposes that the lifting of the anterior hoof wall also pulls the sole upwards causing compression of the circumflex artery under the front of the pedal bone thus compromising the blood supply to the foot.The altered blood supply leads to reduced horn being produced at the front of the hoof whilst growth of horn at the heels is accelerated.

Change in sole conformation

The normally concave sole may become flat or even convex as the pedal bone rotates or sinks within the hoof capsule. The pedal bone may begin to penetrate the sole.This will show as a semicircular area of bruising before the sole is actually penetrated.

Increased width of the white line

In the chronic stage, there is often a widening of the white line at the ground surface due to excessive amounts of horny tissue being produced, especially at the toe. This is an area of weakness that makes the horse susceptible to abscesses and seedy toe. Foot abscesses are a common occurrence in horses with chronic laminitis.

The clinical signs and the response to treatment depend on how much damage has occurred to the laminae.

Laminitis Diagnosis

The diagnosis is made on the clinical signs. Radiographic examination is essential for the following reasons.

  • It is important to establish the position of the pedal bone at the outset of treatment so that subsequent progress or deterioration can be monitored.
  • Radiographs will show the extent of any rotation or sinking of the pedal bone. If the front of the pedal bone is no longer parallel to the front of the hoof wall, the pedal bone has rotated. If the pedal bone is not rotated but has moved downwards within the hoof capsule towards the ground, it is said to be ‘sinking’. This is very important for planning the treatment and also for predicting the likely outcome. ‘Sinkers’ have a much more guarded prognosis.
  • They will also show whether the horse has any foot changes, e.g. thickening of the dorsal hoof wall or remodelling of the toe of the pedal bone from previous episodes of the disease.
  • The vet will place special markers onto the hoof before taking the X-rays. A piece of wire is positioned on the front of the hoof wall extending from the coronary band towards the ground surface.This shows up on the X-ray and the vet can immediately see whether the pedal bone has dropped in relation to the coronary band or if it has rotated so that it is no longer aligned with the anterior hoof wall. If gas or fluid is trapped under the hoof wall, this will show up as a black shadow. A second marker is placed at or just behind the point of the trimmed frog.
  • By taking special measurements from the X-rays, your vet will be in a position to recommend the most appropriate treatment and also to gain some idea of the prognosis.

Definition of terms

Confusion sometimes arises over the terms used to describe the progression of the disease. The term ‘laminitis’ has traditionally been used to describe all stages of the disease but it should ideally be restricted to cases where the animal experiences foot pain but has no obvious hoof changes. Once the pedal. bone has started to rotate and there is a palpable depression above the coronary band at the front of the hoof the condition becomes an ‘acute founder’. If the pedal bone drops Within the hoof capsule so that the coronary band depression extends all round the hoof, the affected animal is described as a ‘sinker’. It is possible for the pedal bone to rotate and sink at the same time. ‘Chronic founder’ cases are those Where there are changes to the appearance of the hoof, e.g. dropped or convex soles, concave anterior hoof wall and growth rings that are wider at the heels than the toe.

Laminitis Treatment

Laminitis should be regarded as an emergency since prompt treatment can make a significant difference to the outcome.There are 3 aims of treatment.

1. To identify and treat any underlying cause

Affected animals should be removed from lush or recently fertilized pastures. If the horse or pony is suffering from an infection or is toxic the treatment is likely to include:

  • antibiotics
  • intravenous fluids
  • flunixin meglumine, a non-steroidal anti-inflammatory drug (NSAID) which has an anti-endotoxin effect, or other NSAIDs with a similar action
  • uterine lavage (flushing) and removal of foetal membranes for animals with a retained placenta
  • treatment to cause dilation of the blood vessels within the hoof and generally lower blood pressure, e.g. isoxuprine and acepromazine (ACP).

If the horse has gorged itself on grain:

  • mineral oil may be given by stomach tube; this will have a laxative effect and by coating the intestinal wall may help to prevent the absorption of endotoxin
  • probiotics may be prescribed to help restore the normal microbial population of the gut
  • electrolytes.

If Cushing’s disease is suspected, the animal should be tested and treated if the disease is confirmed.

2. To prevent the circulating trigger factors reaching the feet

If the horse eats too much grain or becomes toxic for any other reason, the symptoms of laminitis may not appear for up to 48 hours. If the feet can be immediately and continuously cooled with a slurry of iced water, the blood vessels to the feet constrict and the levels of circulating trigger factors reaching the laminae are reduced. The cold may also reduce the activity of the MMPs. It has been shown that keeping the limbs cooled from the top of the cannon bone to the feet for a period of 24-48 hours can help to prevent laminitis developing in situations where it was expected. The horse tolerates the treatment well and does not find the cold water uncomfortable as we would. This needs to be performed under veterinary supervision.

3. To relieve the pain and provide emergency first aid to help stabilize the pedal bone within the hoof capsule and restore the blood supply to the foot

The horse or pony should be managed in the following way.

  • Confined to a stable with a thick, non-edible bed of wood shavings, sand or peat (45cm thick); these materials conform to the shape of the foot and provide some support and comfort.A comfortable bed encourages the animal to lie down more and this reduces the mechanical strain on the laminae.
  • Given non-steroidal anti-inflammatory drugs such as flunixin or phenylbutazone to reduce the pain and inflammation. Flunixin and phenylbutazone may be used together in lower doses during the early stages of laminitis; phenylbutazone is considered to be the most effective analgesic while flunixin has anti-endotoxic effects. The dose should be kept to the minimum necessary to control the pain in order to avoid side effects such as gastric ulceration; this is especially important in ponies and older horses.
  • Fitted with frog supports. As a temporary, emergency measure, the frog may be supported with a roll of bandage, pieces of carpet cut to the shape of the frog or a commercially available frog support pad bandaged in place. If the horse is found in the field, these should be fitted before asking the horse to walk very far; the best solution is to apply frog supports and box the horse if any distance is involved.

How to fit a frog support

  • Pick out the feet and remove any residual debris with a soft brush. Examine each foot carefully. If the frog is level with the weight-bearing surface of the hoof wall or shoe, there is no need to fit a support. Keep the horse on a deep bed of shavings.
  • If the frog is not level with the weight-bearing surface, use a commercially available frog support or place a roll of bandage over the frog so that it ends 1 cm short of the point of the frog. When the bandage is compressed firmly, it should be level with the wall of the hoof or the ground surface of the shoe, if the horse is shod. If the frog support is too thick it will put pressure on the frog and increase the horse’s discomfort.
  • Wrap Elastoplast around the foot to keep the pad bandage in place. Take care not to cause pressure over the heels or the coronary band. The heels should be padded with a layer of cotton wool.
  • If the horse seems more uncomfortable with the frog supports, remove them and keep the horse on a thick shavings bed until the vet arrives.

The frog supports allow some of the horse’s weight to be supported by the frog and this helps to relieve the strain on the weakened laminae. By relieving the pressure on the tip of a rotated pedal bone it reduces compression of the circumflex artery around the toe and helps to restore circulation to the foot.

An alternative first-aid support is the Styrofoam Support System. Styrofoam pads are used to provide support to the frog and also to the back half of the foot. The thick Styrofoam pad is cut so that it covers the sole of the foot and it is then taped onto the bottom of the foot and allowed to compress for 24-48 hours. The pad is then removed and hoof testers are applied to determine which parts of the foot are painful.The front part of the pad is trimmed off and the back part is reapplied to the foot so that it sits 1 cm behind the painful part of the foot. A second pad is applied to the whole hoof and bandaged on top of the trimmed pad. This has the effect of distributing the weight of the horse onto the non-painful area of the foot. With this system in place, it is important to keep the horse on a firm, even surface.

Other Medical Treatments For Laminitis

Several drugs have been used to try and improve the blood flow to the laminae in the feet.

They include:

  • acepromazine
  • isoxuprine
  • glyceryl trinitrate patches placed over the digital vessels.

With improved methods of assessing blood flow through the laminae, the efficacy of these drugs is now being questioned. They should not be used in the developmental stage of laminitis as any increase in blood flow would increase the delivery of trigger factors to the laminae. Acepromazine is helpful for reducing the anxiety of horses and ponies in severe pain and encouraging them to lie down as well as helping to reduce blood pressure.

Management

Feed For Laminitic Horses

Horse and ponies should be kept on a strict forage diet, supplemented with vitamins and minerals.This can be made up of hay plus an alfalfa or alfalfa/straw mix. Soaking the hay is a good way of reducing the levels of soluble carbohydrates and unmolassed sugar beet can be added. Your vet will advise you on the amount to feed. Drastic starvation must be avoided or the horse will be at risk of hyperlipaemia.

Laminitis Supplements

  • Biotin and methionine may be added to improve the growth rate and quality of the horn.
  • A proprietary mix, provides the essential nutrients for hoof growth.
  • A liquid extract of ‘chasteberry’ (Hormonise) may provide symptomatic relief for animals with Cushing’s disease.

Exercising A Horse With Laminitis

Exercise is harmful at any stage until the pedal bone is stable in the foot. Forced exercise is contraindicated, contrary to earlier beliefs. All horses and ponies experiencing laminitis should remain on box rest for at least 4 weeks after they are comfortable at walk and trot in a straight line on a hard surface without any painkillers. This is to allow the laminae time to heal and reduces the chances of subsequent rotation and Sinking. Following this they can be turned out into a riding arena each day and slowly introduced to short periods of controlled walking exercise in hand.

Horse Hoof Care

The aim of hoof care is to minimize the strain on the weakened laminae to prevent rotation or sinking of the pedal bone. The forces acting on the laminae include:

  • The weight of the horse
  • The constant pull of the deep digital flexor tendon
  • The leverage on the toe of the hoof capsule as the horse walks.

Removal Of Shoes

Whether or not the shoes are removed depends on the severity of the case and the condition of the feet. If the hoof wall is strong and the sole is concave, the shoes may be removed.Where the sole has dropped, the horse will be more comfortable with the shoes left on. In cases where the foot is very overgrown or unbalanced and the shoes are contributing to the problem, they are removed carefully to minimize trauma and pain during the removal process.

Corrective trimming and shoeing

The long-term aim of corrective trimming and shoeing is to improve the blood supply to the foot, to restore the normal alignment of the pedal bone and the hoof capsule and to correct the distortion of the hoof capsule. Distortion of the hoof capsule leads to chronic pain because it traumatises the underlying sensitive tissues. Radiographs are important for determining the best way to achieve this and the vet and farrier should work together. Using the X-rays as a guide, the farrier will:

  • Shorten long toes to reduce the forces on the laminae during breakover
  • Rasp back the front of the hoof wall until it is parallel with the pedal bone
  • Remove excessive heel growth in animals with chronic laminitis
  • Fit special shoes where required to support the frog or the whole of the back part of the foot
  • If necessary, the heel will be raised to reduce the tension of the deep digital flexor tendon on the pedal bone.

The corrective trimming is done in stages over several months.Trimming is usually carried out at monthly intervals.

Shoeing A Laminitic Horse

There are currently several popular methods of shoeing affected horses.

Heart bar shoes

There are various types of heart bar shoe. They are designed to provide support to the pedal bone by applying light, even pressure to most of the trimmed frog. This removes the pressure from the compressed blood vessels under the tip of a rotated pedal bone and helps to restore the circulation to the foot.

They require specialist fitting as an incorrectly fitted heart bar shoe can increase the horse’s pain and damage the foot further. Plastic heart bar shoes are now available that can be heated and moulded to fit the foot snugly and correctly.

They are held in place by moulding part of the shoe into indentations drilled into the hoof wall and by a special adhesive. This avoids the pain and concussion caused by nailing shoes in place. The shoe is seated-out to avoid any pressure on the sole.

The equine digital support system (EDSS)

This system of shoeing is used to provide support and transfer the weight bearing to the back of the foot. The weight of the horse is transferred to the frog, sole and bars. The design of the shoe brings the point of break-over back. In some circumstances it is used with special rails that are screwed in place to elevate the heels.

A variety of other shoeing systems are used

These include the use of reverse shoes (normal shoes put on back to front) and a variety of impression materials under pads to provide support. The new technique of using reverse wedge shoeing has been reported as having encouraging results. The choice of treatment depends on the stage of the disease and the circumstances of each individual case.

Surgical Treatments for Laminitis

Vertical grooving of the hoof wall

In order to minimize distortion of the hoof capsule due to the accelerated growth rate of the horn at the heels, a vertical grooving technique has been devised. A vertical groove which extends from the coronary band to the ground surface is made through the whole thickness of the hoof wall at approximately 30 degrees on each side of the dorsal midline. This prevents the lifting of the dorsal hoof wall and the painful stretching and tearing of the sensitive tissues underneath. Styrofoam pads are applied and left on for approximately 2 weeks to protect and support the sole. The hoof wall becomes moist and softens under the tape and this helps the function of the grooves.This procedure has been used early in the acute stages of the disease and also in the chronic recurrent stages to successfully reduce the pain experienced by affected horses and ponies. The procedure will not, however, prevent rotation or sinking in severe cases.

Dorsal wall drilling

Where there is a build up of serum or blood from damaged vessels beneath the front of the hoof wall, the pressure can cause severe pain. Drilling a hole through the anterior hoof wall to release the fluid and relieve the pressure can give the horse considerable relief. This is sometimes used for acute founder and sinker cases.

Dorsal wall resection

Sometimes a section of the front of the hoof wall is removed when it has separated from the pedal bone.This procedure:

  • Allows inflammatory exudate to escape, relieving pressure and pain on the laminae
  • Allows removal of dead tissue and drainage of any infected pockets of tissue
  • Relieves the pain caused by stretching and tearing of the laminae in the dorsal part of the hoof
  • Allows the new horn to grow parallel to the front of the pedal bone.

Cutting the deep digital flexor tendon

This procedure may be used where the position of the pedal bone is unstable and continues to rotate and penetrate the sole due to the pull of the deep digital flexor tendon.With longstanding rotation, the deep digital flexor tendon shortens and prevents the repositioning of the pedal bone. These animals tend to walk on their toes. Surgical cutting of the tendon together with corrective trimming and shoeing permits realignment of the pedal bone and the procedure usually eases the animal’s pain.This operation changes the alignment of the coffin joint and causes hyperextension of the digit and so horses must be shod with extensions at the back of the shoes and raised heels for a period of approximately 3 months to reduce the strain on the joint and the superficial digital flexor tendon.

Abscesses

commonly form in the feet of acutely foundered horses, causing the horse to be very lame.These should be encouraged to burst through the coronary band by tubbing several times a day or relieved by dorsal wall drilling or resection. Drainage through the sole is avoided as the sensitive tissue often swells and protrudes through the hole, taking a long time to heal.When they occur at the back of the foot it should be tubbed frequently and the coronary band should be kept soft and supple by applying udder cream.

Can Laminitis In Horses Be Cured?

The prognosis depends on a number of factors including:

  • The cause of the condition
  • Whether the horse is laminitic, acutely foundered, a sinker or chronically foundered
  • The change in position of the pedal bone within the hoof on X-ray
  • The appearance of the tip of the pedal bone on X-ray; if remodelling has occurred, the animal is unlikely to become pain-free
  • How promptly the correct treatment is given
  • Subsequent management and monitoring.

If the horse is laminitic, i.e. there is no rotation or sinking and it is managed appropriately, it should make a full recovery. Those with mild to moderate rotation have an 80% chance of recovery. If the animal is a sinker or has severe rotation the chance of recovery is reduced to 20%. Up to 80% of chronic founder cases recover if they receive the appropriate care. If there are any complications such as infection, inflammation or resorption of the pedal bone, the prognosis is very poor.

The treatment of severe cases involves many months of corrective trimming and specialist shoeing. The management of these animals is expensive and time-consuming so the commitment of the owner must be 100%. Horses and ponies vary in their ability to withstand the pain. In some cases, the suffering of the animal is so intense that euthanasia is the only reasonable course of action.

Laminitis Prevention

Most cases of laminitis could be prevented by improved management. The following steps should be taken to reduce the incidence of the disease.

What To Feed A Horse With Laminitis

Obesity should be avoided. You should be able to feel your horse’s ribs easily when you run your fingers over his side without being able to actually see them. There should not be any deposits of fat on the crest of the neck, over the loins or tail head or around the udder or sheath. Many show animals are at serious risk of laminitis as a result of overfeeding.

Best Laminitis Supplement

Virginiamycin is an antimicrobial product that prevents multiplication of lactobacilli and Streptococcus bovis. Adding it to the feed of animals susceptible to dietary-induced laminitis reduces proliferation of these bacteria in the hind gut if carbohydrate overload is experienced. This prevents the increased acidity of the gut contents that triggers the sequence of events that leads to laminitis. This drug can help to prevent dietary-induced laminitis but is not a substitute for good management.

How To Prevent Laminitis In Horses

  • The feet of all ponies and horses should be regularly trimmed.
  • Regular exercise is important for all animals to prevent obesity and laminitis.
  • Concussion from working on hard ground should be kept to a minimum.
  • Keep all feed where a loose animal cannot gain access to it.
  • Ensure prompt treatment of any illness that could result in toxaemia.
  • Consult your vet immediately if laminitis is suspected.

Remember that it is much easier to prevent laminitis than it is to cure it.

Leave a Reply

Your email address will not be published. Required fields are marked *