Care of Your Horse's Feet - Part II

Agdex#:	460/20
Publication Date:	03/88
Order#:	88-074
Last Reviewed:	08/97
History:	Additions and revisions by Dr. R.G. Wright/Reprinted in November 1995
Written by:	University of Missouri/Columbia Extension Division; Horse Industry Branch/Alberta Agriculture

Table of Contents

1. Trimming Maintains Foot Balance
2. Maintain Hoof Wall Angle
3. Corrective Trimming
4. Common Causes of Foot Lameness
   
   • Stone in the Foot
   • Bruised Sole
   • Corns
   • Pricked Foot or Puncture Wounds of the Foot
   • Hoof Cracks
   • Thrush
   • Laminitis or Founder
   • Navicular Disease
     
5. Care of Your Horse's Feet - Part I

Trimming Maintains Foot Balance

Trimming of feet is important, though not needed as frequently as cleaning. Trimming should be done at approximately four-week intervals on horses kept in stalls or paddocks. Horses heavily used or in pasture require approximately six-week internals between trimming.

The main goal in trimming is to retain the proper shape and length of the foot. Most people should feel comfortable in cleaning feet, (Figure 1), pulling shoes and trimming feet while they wait for the farrier.

Figure 1.

The bottom of the foot should be kept level and the inside and outside walls should be maintained at equal lengths. The toe of normal feet and pasterns should be 3 inches long; the quarter, 2 inches; and the heel, 1 inch.

The hoof wall should be trimmed with nippers to remove excess length, then a rasp should be used to smooth and level the bottom of the foot. Be sure to rasp from the heel through the toe with each stroke to prevent uneven areas in the hoof wall (Figure 2).

Figure 2.

The white line is external evidence of the lamination (sensitive laminae) between the hoof wall and the coffin bone. The sole of the foot is usually of uniform thickness in a normal horse. Because of that, the sole should not be trimmed to an unnatural shape. To do so would cause parts of the sole to be dangerously thin and tender.

Trimming the sole, referred to as lowering the sole, is done to keep the pressure on the hoof wall rather than on the sensitive inner parts of the foot. The dead, flaky tissue should be trimmed from the sole. Live tissue, elastic when stretched between the fingers, should not be trimmed away (Figure 3).

Figure 3.

Don't trim the frog excessively; it should contact the ground with each step. Trim the frog only enough to remove dead tissue and to provide a uniform and adequate fissure along the junction of the sole and the frog.

After the bearing surface has been rasped to a level surface of proper length, the edges of the wall should be rounded if the horse will not be shod. This prevents chipping and peeling as the foot contacts rocks, logs or other obstructions.

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 Maintain Hoof Wall Angle

Maintain the proper angle of the hoof wall in relation to the ground and the angle of the pastern. Shoes that are left on too

long change the angle of the foot relative to the pastern and can cause lameness. When possible the angle of the hoof wall should approximate the angle formed by the shoulder and the pastern-usually 45 to 54 degrees.

Since the hoof wall is narrower at the heel than at the toe, heels wear first, whether the horse is barefoot or on shoes. Low heels put more stress on the tendons of the leg. If a horse is shod at a 50-degree angle, this angle may change. A 50 -degree angle might be down to 46 or 47 degrees in four to six weeks. This greatly affects the action of the horse and puts more strain on tendons and ligaments.

As the hoof grows larger, the walls at the heels will overlap the shoe. When a shoe presses on the bars, there is serious danger of producing corns in the foot. Running a horse with shoes that have been left on too long also can cause bowed tendons. Regular trimming and shoe re-setting are essential in avoiding these problems.

Foot angle varies from breed to breed and much variation is found among horses of the same breed. Generally, the Western breeds have steeper pasterns and a greater angle at the ground than the other breeds. Unless some correction is needed, as in forging and scalping, the foot should be trimmed to its natural angle because any change would result in stress in other areas of the column of bones of the leg.

Trim the heels low enough to promote expansion and prevent contraction of the heels. The main concern is to trim often enough to prevent cracking and uneven wear which could eventually contribute to the improper set of the feet and legs. With a little practice, most horse owners should be able to routinely trim horses feet that do not need corrective work. It is wise, however, not to take a chance on compounding a problem on horses that need corrective trimming. To prevent harmful mistakes, seek the help of a professional farrier when trying to correct an improper turn or set of the feet and legs.

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Corrective Trimming

The most common deviations from a normal set of feet and legs are toe in (pigeon toed) and toe out of either front or rear feet. Other problems commonly helped by trimming are cocked ankles, buck knees, calf knees, sickle hocks, and slight rotations of the cannon bone. Also, some common faults in movement of feet in stride-forging, scalping, interfering and brushing-are corrected by careful trimming.

The most important aspects of good foot care are regularity, frequency, cleanliness and the use of proper corrective measures.

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Common Causes of Foot Lameness

This section is included to give the reader a background concerning the recognition, cause, treatment and outcome of the common conditions which produce lameness in the horse. An attempt has been made to keep the information practical and in language the layman will understand. However it is necessary to refer to anatomical, conformational and physio-logical aspects of the horse in order to give accurate informa-tion. Refer to Figure 2 and 3, Part I of the Factsheet.

Many and varied treatments are available for lameness, once an accurate diagnosis is made. Diagnosis may be as simple as a physical examination done by your practicing veterinarian or as complicated as special radiographic tests at a veterinary teaching hospital. Treatments vary from simple rest to complicated surgery, with corrective trimming and shoeing, anti-flammatory drugs, bandaging, cold hosing, acupuncture, electrical stimulation and many others coming in between. It must be remembered that an accurate diagnosis is the first step in any case, and veterinary services should be used.

Most lameness, particularly of the forelimbs, is found from the fetlock down. In the hind limb, the hock is often involved. As in any case of lameness, start to look for causes from the foot up.

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Stone in the Foot

 This occurs suddenly, and usually while at work, particu-larly on a gravel road. Stones often lodge between the shoe and the frog causing considerable discomfort. Stones should be removed immediately before further damage can occur.

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Bruised Sole

 This is direct injury of the flat of the hoof or sole by stones, irregular ground or injury. Bad shoeing may also cause this. Rest and corrective shoeing are usually all that is needed. If unresponsive, veterinary assistance should be sought.

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Corns

Corns are the result of bruising of the sole between the bar and the hoof wall. This is most often the result of poorly fitting shoes or neglect to have the horse re-shod at reasonable intervals. Corns can be simple and classified as dry, or they can become infected. Dry corns are treated by relieving the pressure. Remove the shoe, clean the foot thoroughly and reapply a 3/4 length shoe, or rest without shoes if possible. If the corn is infected it will appear moist and be draining serum or pus. In these cases veterinary assistance should be ob-tained.

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Pricked Foot or Puncture Wounds of the Foot

Puncture wounds of the foot are common and can cause severe lamenesses that may lead to permanent disability or death if not properly treated. As with any wound that allows bacteria to enter the body, there is a serious threat of infection occurring, necessitating veterinary care to prevent serious consequences (e.g. tetanus). Abscesses can develop in as little as two days following the initial injury. Often the site of puncture is very difficult to find by visual examination; a hoof knife, hoof testers and/or radiographs can be used to locate and evaluate the injury. The outcome of foot punctures depends on the area of the foot affected, the type of puncturing object, and whether secondary infection occurs. In all cases early veterinary care is essential to evaluate the damage done and prevent further damage from occurring.

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Hoof Cracks

Hoof cracks, extending from the ground surface upward, are common problems in horses' hooves which are not trimmed or are excessively dry. Injury to the hoof forming tissue at the coronary band can also result in cracks; these extend from the coronary band downwards. Severe lameness can be produced if bacteria enter the cracks and gain access to the sensitive structures of the foot causing infection. Cleaning and treating of the crack, followed by proper trimming and shoeing can be used to alleviate the condition until the hoof wall grows out (about 1 cm growth per month). The applica-tion of fiberglass or plastics to the hoof wall can also produce excellent results when applied by a competent farrier or veterinarian. Hoof cracks can usually be prevented by peri-odic hoof trimming and preventing the hooves from becoming excessively dry and hard. Standing a horse in water or mud periodically will help to keep its feet soft. The application of hoof dressing is helpful to prevent moisture escaping from the hoof; however these should be applied to hooves already dry. Neat's foot oil is an excellent agent for moisturizing dry hooves.

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Thrush

Thrush is a bacterial infection of the frog and sole of horses kept in unclean conditions. Affected feet will have a very offensive odour and will show a black discharge around the frog. Lameness will result if the condition is allowed to progress far enough to affect the sensitive structure of the foot. Proper cleaning and trimming of the foot along with proper stable sanitation will remove the cause of the infection. Affected horses can be treated by cleaning and trimming the foot and disinfecting it with a phenol or iodine solution. The foot can also be packed with cotton soaked with 15 per cent sodium sulfapyridine solution.

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Laminitis or Founder 

Laminitis is an inflammation of the laminae that bind the hoof wall to the coffin bone. The causes of laminitis are varied and in many cases obscure. The commonly recognized causes are:

• overeating of grain
• ingestion of cold water by a hot horse
• retained afterbirth
• overfat horses (especially shetland ponies)
• idle horses pastured on lush green pasture (especially if clover or alfalfa are present) 

Regardless of the cause, the signs of laminitis will be similar. In the early or acute stages the hoof and coronet will be hot, the horse will often sweat and will be reluctant to move. Because the front feet are usually the most severely affected, the horse will be camped out in front (front feet out in front of the body) and camped under (hind feet well under the body) behind in an attempt to remove weight from his front feet. In cases where all four feet are affected the horse will stand under himself both in front and behind as though he were attempting to balance on a barrel.

In advanced or chronic cases of founder there is usually an exaggeration of the ring formation on the hoof wall and there will be decreased arch to the sole (dropped sole). In severe cases the coffin bone will protrude through the sole. The afflicted horse may spend most of his time lying down. A chronically foundered horse will exaggerate his attempts to land heel first while in motion.

Treatment of early laminitis varies with the cause. When-ever a horse is suspected of having laminitis a veterinarian should be called immediately and the horse exercised (mild exercise) until the veterinarian arrives.

If not severely affected, horses with chronic laminitis can be useful for most types of work if proper foot care is instituted.

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Navicular Disease

Navicular disease is lameness of the front feet caused by injury to the navicular bone. It is a very common lameness, particularly in breeds which have genetic defects in conforma-tion. Defects in conformation such as upright pasterns and straight shoulders and/or small feet impair the shock absorb-ing mechanisms of the front legs and predispose the horse to navicular disease. Similarly, heavy use on hard ground will increase the probability of navicular disease. Affected horses are usually lame in both front feet. Because of the pain they will alternately "point" or advance one front foot at a time to remove the weight from it and thus reduce the pain. In the early stages of the disease, resting the horse can make the symptoms disappear, but when returned to work the horse will soon become lame. Eventually, the affected foot or feet will become smaller than normal, the walls steeper, the heels contracted and the frog shrunken because the horse will attempt to reduce the pain by landing toe first rather than heel first as he moves. Corrective hoeing, pain killers and neurec-tomy (cutting the nerves to the back surface of the foot) can prolong the useful lifespan of the horse. Accurate diagnosis and treatment of navicular disease requires radiographic examination of the navicular bone in the horse's hoof, but at Dresent there is no known cure for the condition.

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