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Chapter 7 Unsoundness.

Unlike other farm animals, the horse is serviceable only when in motion. Any abnormal deviation in the structure or action of a horse can render it partly or completely useless. Any defect that affects serviceability, for example, lameness, blindness, faulty wind, and so on, is considered an unsoundness.

Those defects that detract from appearance but do not impair serviceability are considered blemishes, for example, scars, capped hocks, and elbows. Blemishes are looked down upon in gaited, parade, and some pleasure horses. They are more common in stock horses and tend to detract less from their value than from other types of horses.

An important part of selecting a horse is the ability to recognize common unsoundnesses and blemishes and faulty conformation that tends to predispose the animal toward unsoundness and blemishes.

OBJECTIVES

After completing this chapter, you should be able to:

* Distinguish between a blemish and an unsoundness

* Describe the common treatment for many of the problems that could develop into an unsoundness

* Name four common unsoundnesses associated with the head

* List five common unsoundnesses or blemishes that can be found on the body

* Describe two types of unsound lungs

* Name and describe 10 unsoundnesses or blemishes of the front or hind leg

* Differentiate between a sprain and a fracture

* Name two types of sprains and two types of fractures

* Identify four conditions that predispose a horse to developing unsoundnesses

* Name and describe six stable vices affecting usefulness

* Describe how to methodically examine a horse for soundness

KEY TERMS

allergy

anti-inflammatory

atrophy

bars

blemish

boot

bowed tendons

calcification

calks

collar

congenital

conservative treatment

cribbing

degree of finesse

fibrosis

flexion tests

founder

fracture

heaving

high ringbone

hobble

hock

hoof testers

hydrotherapy

implants

laminitis

lateral cartilages

low ringbone

malocclusion

ossify

patella

plates

plumb line

poll

sensitization

shoe boil roll

sidebones

sprain

stifled

straight shoulders

tail board

ulcerate

umbilicus

unsoundness

upright pasterns

vices

BLEMISHES VERSUS UNSOUNDNESS

Basically, an unsoundness is any condition that interferes or is apt to interfere with the horse's function and performance. In horse show halter classes, horses with an unsoundness usually do not place. In performance classes, if the apparent unsoundness is not interfering with the horse's action, it is given little consideration. A blemish differs from an unsoundness in that it is unattractive, but it does not and is not apt to interfere with the horse's performance.

Blemishes are usually an acquired physical problem that may not make the horse lame but may still interfere with the action of the horse. An unsoundness is usually caused by poor conformation and will tend to be a problem throughout the horse's lifetime. Often an unsoundness is also a blemish. Both are usually caused by stress and strain placed unevenly on the legs. The location and severity of the problem determines how the horse will be affected.

A blemish may or may not affect the level of performance. An unsoundness usually affects the performance of the horse, at least temporarily. How the horse is used must be considered when evaluating the importance of the problem. A pleasure horse that receives minimal stress and is ridden infrequently will have a different evaluation than a horse that is at a high level of competition and is being shown and trained vigorously.

Treatment methods vary for these problems. Basic treatment for an injury usually consists of rest to stop further trauma, hydrotherapy--applying cold water to the affected area, usually hosing the leg for a while--and medications to help reduce swelling. Pain relievers may also be given if necessary. A veterinarian can inject medications into areas to reduce inflammation and swelling. Some problems also have surgical treatments. A veterinarian needs to be consulted to determine the amount and location of damage and the best treatment for the horse.

CAUSES OF UNSOUNDNESS

Horses may be lame due to some disease or affliction in the joints, tendons, ligaments, or muscles. Usually lameness from these causes cannot be seen and calls for a diagnosis by a veterinarian. Conversely, many unsoundnesses or indications of unsoundness can be seen. Many unsoundnesses and blemishes are due to excessive stress and strain beyond the endurance of the bone or muscle, injury to a bone or joint, inherited conditions, or nutritional deficiencies.

LOCATION OF COMMON BLEMISHES AND UNSOUNDNESSES

For discussion purposes, some of the common blemishes and unsoundnesses are grouped here according to their location on the body--the head, body, lungs, and limbs.

Studying Figure 7-1 to become familiar with the location of some blemishes and unsoundnesses and reviewing the muscular and skeletal systems in Chapter 5 will aid your understanding of this chapter.

Unsoundness of the Head

Unsoundnesses around and relating to the head include blindness, bad mouth, poll evil, and quidding.

Blindness. Blindness seriously affects the usefulness of a horse. It is usually characterized by cloudiness of the cornea or complete change of color to white. Pale blue, watery eyes may indicate periodic ophthalmia (moon blindness). Watery eyes may appear as a result of vitamin A deficiency. These conditions are not common in horses on pasture.

Moon Blindness. Periodic ophthalmia or moon blindness is an inflammation of the inner eye due in part to a vitamin B deficiency. It usually impairs vision, and treatment is usually unsuccessful.

Bad Mouth. Bad mouth is a term used to describe various jaw or tooth misalignments. Bad mouth may be a malocclusion where the top and bottom teeth do not meet, or a monkey mouth (undershot jaw) where the lower jaw and tooth structure extend beyond the top teeth. Parrot mouth, or overshot jaw, is another example. In this case the top jaw and incisor teeth extend beyond the lower jaw. A bad mouth is considered an inherited unsoundness (Figure 7-2).

[FIGURE 7-1 OMITTED]
Xenophon Treatise on Horsemanship

Xenophon (430[?] to 357 B.C.) was an
Athenian soldier, writer, and disciple of
Socrates. Besides many other writings,
Xenophon wrote On the Art of Horsemanship.
This is the earliest preserved book on the care
and training of horses. He had a clear understanding
of the nature of horses. Much of his
advice is still good today. From his translated
works, here is what Xenophon had to say about
the conformation of a colt.

For judging an unbroken colt, the only criterion,
obviously, is the body, for no clear signs of
temper are to be detected in an animal that
has not yet had a man on his back.

In examining his body, we say you must first
look at his feet. For, just as a house is bound to
be worthless if the foundations are unsound,
however well the upper parts may look, so a
war-horse will be quite useless, even though all
his other points are good, if he has bad feet; for
in that case he will be unable to use any of his
good points.

When testing the feet first look to the hoofs.
For it makes a great difference in the quality of
the feet if they are thick rather than thin. Next
you must not fail to notice whether the hoofs
are high both in front and behind, or low. For
high hoofs have the frog, as it is called, well
off the ground; but flat hoofs tread with the
strongest and weakest part of the foot simultaneously,
like a bow-legged man. Moreover, Simon
says that the ring, too, is a clear test of good
feet: and he is right; for a hollow hoof rings like
a cymbal in striking the ground.

Having begun here, we will proceed upwards
by successive steps to the rest of the body.

The bones [of the pastern] above the hoofs
and below the fetlocks should not be too upright,
like a goat's: such legs give too hard a tread, jar
the rider, and are more liable to inflammation.
Nor yet should the bones be too low, else the
fetlocks are likely to become bare and sore when
the horse is ridden over clods or stones.

The bones of the shanks should be thick,
since these are the pillars of the body; but not
thick with veins nor with flesh, else when the
horse is ridden over hard ground, these parts
are bound to become charged with blood and
varicose; the legs will swell, and the skin will fall
away, and when this gets loose the pin, too, is
apt to give way and lame the horse.

If the colt's knees are supple when bending
as he walks, you may guess that his legs will
be supple when he is ridden too, for all horses
acquire greater suppleness at the knee as time
goes on. Supple knees are rightly approved,
since they render the horse less likely to stumble
and tire than stiff legs.

The arms below the shoulders, as in man,
are stronger and better looking if they are thick.

A chest of some width is better formed both
for appearance and for strength, and for carrying
the legs well apart without crossing.

His neck should not hang downwards from
the chest like a boar's, but stand straight up to the
crest, like a cock's; but it should be flexible at
the bend; and the head should be bony, with a
small cheek. Thus the neck will protect the rider,
and the eye see what lies before the feet. Besides,
a horse of such a mould will have least power of
running away, be he never so high-spirited, for
horses do not arch the neck and head, but
stretch them out when they try to run away.

You should notice, too, whether both jaws
are soft or hard, or only one; for horses with
unequal jaws are generally unequally sensitive
in the mouth.

A prominent eye looks more alert than one
that is hollow, and, apart from that, it gives the
horse a greater range of vision.

And wide open nostrils afford room for freer
breathing than close ones, and at the same
time make the horse look fiercer, for whenever a
horse is angry with another or gets excited
under his rider, he dilates his nostrils.

A fairly large crest and fairly small ears give
the more characteristic shape to a horse's head.
High withers offer the rider a safer seat and
a stronger grip on the shoulders.

Reading Xenophon's translation lets us know
how much we rely on the knowledge of generations
in the past. For the person interested in
reading the entire translated text, it can be found
on the Internet and downloaded at <http://www.
ability.org.uk/project_gutenberg_e.html>.


[FIGURE 7-2 OMITTED]

Poll Evil. Poll evil is a fistula--a lesion or sore--on the poll that is difficult to heal. Poll evil (Figure 7-1) is an acquired unsoundness resulting from a bruise or persistent irritation in the region of the poll. Its cause is Brucella abortus, the same organism that causes Bang's disease in cattle. Early symptoms are swelling and touchiness around the head and ears when the horse is being bridled. Severe inflammation, eruption, and bad scars may result if the wound is neglected.

Quidding. Quidding is seen when horses drop food from the mouth while chewing. This is usually caused by bad teeth or bad gums (stomatitis or gingivitis). It can also be caused by paralysis of the tongue. If there are sharp edges or points on the teeth, chewing will cause the horse pain when the points rub or cut the tongue and/or gums. Floating (filing) the teeth to remove the points and local treatment of sores will help. Soft palatable feed can be given to soothe sore gums.

When quidding is accompanied by pain while eating or when the bit is in the mouth, dental problems or the absence of teeth should be suspected. If quidding is accompanied by bad breath and weight loss, gum disease is a likely cause. Routine dental care and mouth washing will help. In severe cases, anti-inflammatory drugs and pain relievers may help the horse feel more comfortable.

Unsoundness and Blemishes of the Body

Fistulous withers, sweeney, knocked-down hip, scars, and hernias are considered unsoundnesses and blemishes of the body.

Fistulous Withers. This is an inflammation affecting the withers in much the same way as poll evil affects the poll. It may be present on one or both sides of the withers (Figure 7-1). It should be treated early. Otherwise the disease can linger on, resulting in severe infection and occasionally a crestfallen condition of the neck immediately in front of the withers.

Sweeney. Sweeney (Figure 7-1) applies to a wasting away of the shoulder muscle overlying the scapula of the horse. This is muscle atrophy of the shoulder caused by damage to a nerve in the shoulder. The damage is usually from direct trauma to the shoulder from a kick, running into a wall or solid object, or even running into another horse. It is characterized by the loss of muscle on either side of the spine of the scapula. The spine of the scapula is normally not seen but will become visible as the muscles atrophy. Depending on the amount of nerve damage and the resulting muscle loss, there will be varying amounts of lameness. The gait of a horse with sweeney is usually characterized by swinging the leg out as it comes forward due to lack of support from the atrophied muscles. Nerve damage is almost always permanent.

Knocked-down Hip. This is a fracture of the external angle of the hipbone (ilium). It results in a lowering of the point of the hip that can be identified best by standing directly behind the horse. Hurrying through narrow doors, crowding in trailers, falling, and injury from other causes may be responsible. Usefulness is seldom impaired, but appearance is greatly affected.

Scars. Scars are marks left on the skin after the healing of a wound or sore. They may appear on any part of the body. A scar is often noticed because of the presence of white hairs. Working stock horses with scars are not discriminated against very much, but gaited and parade horses are seriously faulted for them.

Hernia. A hernia is generally the passage of a portion of the intestine through an opening in the abdominal muscle (see Figure 7-1). It may appear on any portion of the abdomen, but is more common near the umbilicus. Hernias are usually not serious enough to cause an unsoundness.

Unsoundness of the Lungs

Any permanent abnormality in the respiration process is a serious unsoundness. Two well-known conditions include roaring and heaving.

Roaring (whistling). A paralysis or partial paralysis of the nerves that control the muscles of the vocal cords may result in a roaring or whistling sound when air is inhaled into the lungs. The condition is seldom apparent when the horse is at rest, but it becomes obvious upon exertion. Roaring may be limited to one nostril and can be determined by plugging each nostril alternately.

Heaving. Heaving is caused by a loss of elasticity in the lungs resulting from a breakdown in the walls of a portion of the air cells. The condition is characterized by a visible extra contraction of the flank muscles during expiration. The expiration process can be seen, and often heard, to proceed normally to about two-thirds of completion, when it is stopped. The flank and lower rib muscles contract briefly, then expiration continues to completion. Dusty hay and/or atmosphere, severe exertion of horses out of condition, and respiratory infections are common causes of the condition.

Unsoundness of the Limbs

The hock is the most vulnerable, and the most important, joint of the body. All of the power of a pulling horse is generated in the hindquarters and transmitted to the collar by contact with the ground via the hocks. Working stock horses must bear most of the weight on the hind legs by keeping their hocks well under them if they are to attain maximum flexibility. Degree of finesse is determined with gaited and parade horses by how well they "move" off their hocks.

Structurally sound hocks should be reasonably deep from top to bottom; well supported by fairly large, flat, straight bone; characterized by clean-cut, well-defined ligaments, tendons, and veins; and free from induced unsoundness and blemishes.

There are many unsoundnesses and blemishes to the limbs. Some conditions are correctable; some are not. The following discussion does not identify and discuss every blemish or unsoundness of the limbs. For more detail and additional unsoundnesses, the reader should follow up with some of the sources identified in the Additional Resources at the end of the chapter.

Bog Spavin. This is a serious discrimination. Bog spavin (Figures 7-1 and 7-3) is a soft, fluctuating enlargement located at the upper part of the hock due to a distention of the joint capsule. It is the result of horses trying to straighten the hock and trauma such as quick stops and turns or getting kicked by another horse.

[FIGURE 7-3 OMITTED]

Bone Spavin. A bone or jack spavin (Figures 7-1 and 7-3) is a bony enlargement at the base and inside back border of the hock. It is a common unsoundness of light horses, especially those with sickle hocks or shallow hock joints from top to bottom surmounting fine, round bone. Such conformation should be seriously faulted in a working stock horse. In the early stages, lameness may be apparent only when the horse has remained standing for a while. Bone spavins, like ringbones, may fuse bones and render joints inarticulate.

Bowed Tendons. Bowed tendons (Figures 7-1 and 7-3) are apparent by a thickening of the back surface of the leg immediately above the fetlock. One or more tendons and ligaments may be affected, but those commonly involved are the superflexor tendon, deep flexor tendon, and suspensory ligament of one or both front legs. Predisposing causes are severe strain, wear and tear with age, and relatively small tendons attached to light, round bone. Bowed tendons usually cause severe unsoundness.

Buck-kneed. Buck-kneed (Figures 7-1 and 7-4) is also called over-at-the-knee. Because the knee is in front of the plumb line, the leg is not straight. This can be the result of a shortening of the muscles on the front of the knee. It can be present in foals, but usually disappears by about 3 to 4 months. If it is congenital and a permanent condition, the forwardness will cause excessive strain on the leg.

[FIGURE 7-4 OMITTED]

Bucked Shins. Bucked shins (Figure 7-3) occur on the front, top part of the cannon bone, below the knee. The forelimbs are affected more often than the hind limbs. Bucked shins are caused by trauma to the surface of the bone, possibly from stress on the tendons that run down the cannon bone or possibly from the forces distributed up the bone during fast work. This is usually the result of overwork and overtraining, especially in young racehorses. It is seen most commonly in racing Thoroughbreds, quarter horses, and Standardbreds.

Bucked shins can be mild to severe depending on the amount of stress applied to the bone. If severe, the bone may have a fracture. Because of this, the prognosis depends on the amount of injury. A swelling exists over the area that is affected and lameness may be present. In a mild case, rest and mild hand-walking are recommended. When the pain has decreased, a horse should be put on a controlled exercise program to get back into shape.

The greater the severity of the bucked shin, the longer the rest and controlled exercise program will need to be extended. A variety of surgical procedures are available to correct fractures, if necessary.

Calf-kneed. Calf-kneed (Figure 7-5) is a deviation of the knee joint behind the plumb line (the opposite of buck-kneed) so the leg is not straight. This places great strain on the tendons and ligaments running down the back of the leg. Compression of the bones in the knee joint also increases, leading to chip fractures. This is a serious problem. The horse is generally unable to tolerate heavy work.

[FIGURE 7-5 OMITTED]

Camped-out. The camped-out leg (Figures 7-5, 7-6 and 7-7) is too far back and behind the plumb line. Usually the whole leg is involved and the plumb line is at or in front of the toe instead of behind the heel. This is often seen accompanied by upright pasterns and straight hocks in the hind limbs, which causes increased concussion on the navicular bone, pastern, fetlock joint, and hock. Camped-under is the opposite condition.

Capped Elbow. Sometimes called a shoe boil (Figure 7-3), this is a blemish at the point of the elbow. Capped elbow is usually caused by injury from the shoe when the front leg is folded under the body while the horse is lying down. Shoes with calks (heels) cause more damage than those with plates.

[FIGURE 7-6 OMITTED]

[FIGURE 7-7 OMITTED]

Capped Hock. This is a thickening of the skin or large callus at the point of the hock. It is a common blemish. Many capped hocks (see Figures 7-1 and 7-3) result from bumping the hocks when the horse is being transported in short trailers or in trailers with unpadded tail gates.

Chip Fractures. Chip fractures can occur in several different places but are most common at the knee, and they are the most common problem that affects the knee. Chip fractures are small fractures that break off one of the bones in the knee. They are usually caused by high amounts of concussion and stress on the knee and are seen most frequently in racehorses: Thoroughbreds, Standardbreds, and quarter horses. They also can be seen in any highly athletic horse, such as barrel racers, steeplechasers, hunters, and jumpers.

The knee is able to absorb a great deal of shock due to the many joint spaces and fluid within it. Normally, the horse is able to distribute shock by correctly lining up the bones of the knee. However, as the horse extends the knee and becomes fatigued while performing, the position of the bones may shift slightly. This decreases the knee's ability to disperse the forces. Additionally, as the horse fatigues, the flexor muscles on the back of the leg tire and allow for overextension of the knee. This compresses the front of the knee and creates high forces on the front of the bones.

The amount of damage that occurs depends on:

* Age of the horse (younger horses' bones have not matured as much and are more likely to be injured)

* Activity of the horse and its training level (the more strain put on the knee, the more likely it is to get a fracture)

* Conformation (horses with knees that do not line up properly at any time, will have greater strain on the knee all the time)

* Improper trimming and shoeing (an uneven foot or broken hoof-pastern axis will change the distribution of the forces across the knee)

Most chip fractures occur in the front of the bones at the radial carpal bone, intermediate carpal bone, and third carpal bone. Chip fractures are generally small. Names for other types of fractures indicate an increase in size, for example, corner fractures and slab fractures.

The horse with a chip fracture will show inflammation, swelling, pain, and lameness at the knee. The nature of the signs generally depends on the amount of trauma to the bones. If the fracture is new, the swelling tends to be diffuse across the knee; but over time, the swelling accumulates over the area of the chip. By feeling the knee, a veterinarian can usually find signs of tenderness. Flexion tests help to determine the extent and location of the fracture. X-rays and lameness tests are also used to diagnose the problem (Figure 7-8).

Two types of treatments are available--surgical or conservative. Treatment is usually dictated by the location and severity of the fracture and the amount of lameness. Conservative treatment is usually chosen for small fractures that do not appear to be troubling the horse much and are not affecting the joint. Treatment is stall confinement and hand-walking for a period of weeks or months. Anti-inflammatory drugs can be used to lessen the pain and decrease inflammation. Surgery is reserved for large fractures or fractures that have been displaced and are adversely affecting the horse and the joint.

The recovery of the horse is based on the amount of damage to the joint caused by the fracture. Mild cases generally have a very good prognosis. If the horse is not able to recover to its original athletic level, it may be suited for a less strenuous exercise program. A veterinarian will be able to provide advice.

Cocked Ankles. Cocked ankles (see Figure 7-1) may appear in front but are more common in hind legs. Severe strain or usage may result in inflammation or shortening of the tendons and a subsequent forward position of the ankle joints. Advanced cases impair movement and decrease usefulness.

[FIGURE 7-8 OMITTED]

Contracted Feet. Contracted feet are caused by continued improper shoeing, prolonged lameness, or excessive dryness. The heels lose their ability to contract and expand when the horse is in motion. Horses kept shod, those with long feet, and those with narrow heels are susceptible to the condition. Close trimming, going barefooted, or corrective shoeing usually produces sufficient cure to restore the horse to service.

Contracted Heel. (Figures 7-9a and 7-9b) This results when the back of the foot, or the heel region, becomes narrower than normal. Contracted heel is more common in the front feet than the hind feet. Contracted heel is usually accompanied by a small frog (an elastic formation on the sole of the foot) and a sole that is concave or "dished." A small frog indicates that the frog is not being compressed when the horse is walking.

As the frog shrinks in size with decreased use or overtrimming, the heel contracts. If the heels become too contracted, lameness may result. Contracted heels are usually caused by improper shoeing/trimming and hoof growth. Lameness can also cause this condition if the horse is not applying weight to the foot. The treatment is corrective shoeing. Depending on the severity of the problem, it may take a year or more to get the heels spread to the correct width for the foot.

Corns. Corns appear as reddish spots in the horny sole, usually on the inside of the front feet, near the bars. Advanced cases may ulcerate and cause severe lameness. The causes are many, but bruises, improper shoeing, and contracted feet are the most common. Corns respond to treatment and proper shoeing.

[FIGURE 7-9a OMITTED]

[FIGURE 7-9b OMITTED]

Club Foot. In this condition the foot axis is too straight and the hoof is too upright. Club foot is usually associated with a problem such as contracted deep digital flexor tendon. It may be due to injury (one foot), improper nutrition (two or more feet), or possibly heredity. The upright foot causes the horse to be stiff and rough in its gait and may make it unrideable. Additionally, because the horse cannot flex and extend its foot correctly, it has a tendency to stumble. The nutritional condition may be correctable. The horse that inherits the problem should not be bred to prevent the further passage of the problem.

Curb. Curb (see Figures 7-1 and 7-3) is an enlargement on the back of the leg, just below the hock. It is caused by trauma that causes the plantar ligament to become inflamed and then thickened. Curb is seen with faulty conformation (such as in sickle- and cow-hocked animals) and with horses that slide too far, too fast in deep ground. Direct trauma, such as a kick from another animal or the horse kicking a hard object, may also stress the ligament and cause a curb. At first, a curb causes pain; then heat and swelling.

The horse should be rested until the swelling and pain have decreased. Anti-inflammatory drugs may be used. If the trauma does not affect the hock joint, there is often a good prognosis following treatment. The swelling will diminish, and often just a blemish is left. If the horse has conformation problems that are causing the curb, it is unlikely to heal completely and permanent lameness may persist.

Flat Foot. This type of conformation lacks the natural concave curve to the sole. Instead, the sole is flat and predisposed to more contact with the ground. Flat foot increases the chances for sole bruises and resulting lameness. To avoid pain and pressure from hitting the ground with the sole, the horse may learn to place its heel down first. This is more common in the front feet than in the rear. Generally, this conformation is not seen in light horse breeds, but may be seen naturally in some draft breeds. Corrective shoeing may help alleviate some of the contact with the ground.

Founder or Laminitis. Founder or laminitis (see Figure 7-1) is an inflammation of the sensitive laminae that attach the hoof to the fleshy portion of the foot. Its cause is probably a sensitization (allergy). When horses gain access to unlimited amounts of grain, founder often results. Other conditions conducive to founder are retained placenta after foaling and sometimes lush grass. All feet may be affected, but front feet usually suffer the most. Permanent damage usually can be reduced or eliminated with immediate attention by a veterinarian. Permanent damage results from dropping of the hoof sole and upturn of the toe walls when treatment is neglected.

Fractures. A fracture is a broken bone. These breaks range in degrees of seriousness. A fracture of any kind usually causes some degree of lameness depending on the bone that is fractured. In the past, fracture healing in horses often caused an altered function. With a greater demand for improved techniques, fracture repair has evolved. Some serious fractures of the long bones can be repaired with implants that can withstand massive mechanical force applied to a bone.

Navicular Disease. Navicular disease is an inflammation of navicular bone and bursa. The condition causes lingering lameness and should be diagnosed and treated by a veterinarian. Often the exact course is difficult to determine. Hard work, upright pasterns, small feet, and trimming the heels too low may predispose a horse to navicular disease. Special shoeing, bar shoes, or pads may help. If not, the navicular nerve can be cut so the horse has no sensation in the foot. The horse then may be dangerous to ride because it cannot feel the ground. Many horses, however, have had the nerve cut and remained useful for many years.

Osselets. These are soft swellings on the front and sometimes sides of the fetlock joint. Osselets (see Figure 7-3) are due to injury to the joint capsule of the fetlock. This trauma affects the surface of the bone where the joint capsule attaches to it. Tearing of the joint capsule causes inflammation that stimulates the bone to heal by laying down more bone. During the inflammation stage, pain, heat, and swelling are present. The horse is almost always lame and will have a shortened stride.

Osselets are often seen in racehorses, especially in young horses under a lot of strain from training. The earlier the injury is treated, the better the prognosis. Rest and hydrotherapy are important in the early stages to decrease pain and swelling. X-rays are often taken to check for complications, such as fractures. A veterinarian should be consulted for the best treatment. If the joint is not affected by the bony growth, the prognosis is often good. If the joint is involved, decreased joint movement, leading to decreased performance, often results.

Pedal Osteitis. This condition is caused by chronic inflammation to the coffin bone, usually of the front foot. It is usually due to persistent pounding of the feet, chronic sole bruising, or laminitis. Pedal osteitis is usually detected over the toe of the coffin bone and is caused by a decrease in the density of the bone in response to the trauma. Pedal osteitis is commonly associated with laminitis.

Clinically, the horse may be lame at all gaits depending on the progression of the bone demineralization. Hoof testers will pick up increased sensitivity, commonly over the toe. X-rays may show a roughening of the edge of the toe or wings of the coffin bone and an increased size of the channels of the blood vessels that run through the bone. Pedal osteitis can be hard to diagnose with X-rays. Clinical signs of lameness and location of the sensitivity are important clues.

Treatment usually consists of corrective shoeing to take pressure off the sole and toe. Pads may be used to help cushion the feet. Anti-inflammatory drugs can also help relieve some of the pain.

Pointing. The front legs bear about 60 percent of the weight of a horse. Healthy horses stand at rest with weight equally distributed on both front legs. Lameness in the foot or leg will cause "pointing." Pointing refers to a state of rest with one foot positioned about 10 to 12 inches ahead of the other in an effort to reduce weight on the affected side. Weight is shifted habitually from one hind limb to the other by healthy horses during rest and does not indicate lameness (Figure 7-10).

Cracks. Quarter, toe, or heel cracks (see Figures 7-1 and 7-3) can indicate poor owner management of the feet. These cracks can appear in either the toe, quarters, or heel of the hoof wall, or in any combination of these locations. Toe and quarter cracks are the most common. Usually these are associated with a hoof wall that is too long and has not been trimmed frequently enough. Cracks can also develop with horses that are in rain and mud for long periods of time. The mud draws water out of the hoof wall, and when the hoof dries it often cracks.

[FIGURE 7-10 OMITTED]

The cracks can be small and cause no problems. If cracks extend up the wall and into the sensitive lamina of the hoof wall, the horse is usually lame. Cracks often worsen if left untended because the weight of the horse, especially when moving, puts pressure on the hoof and the crack. For treatment, the hoof should be kept moist and treated as soon as cracks are detected to stop any permanent damage. If cracks are extensive, the veterinarian may need to remove the cracked area to promote new hoof growth.

Quittor. A quittor is a festering of the foot anywhere along the border of the coronet (see Figure 7-1). It may result from a calk wound, neglected corn, gravel, or nail puncture.

Ringbone. Ringbone (see Figures 7-1 and 7-3) is a bony enlargement on the pastern bones, front or rear. It occurs in two locations distinguished by the names high ringbone and low ringbone. They both occur around the pastern bone (the second phalanx). High ringbone occurs at the pastern joint. Low ringbone occurs at the pastern-coffin bone joint at about the level of the coronet band. Ringbone is caused by bony development around these joints due to tearing and damage of the ligaments and tendons at these bones.

Tearing damages the surface of the bone and stimulates production of new bone in these areas. Typically, this occurs in the forelimbs. It can occur on the front and sides of the joints, but rarely on the back of the joint. Damage to the tendons and ligaments can occur from overuse, due to excess stress placed on the structures.

Conformation problems often worsen the stress placed on the tendons and ligaments. Especially stressful are straight shoulders and upright pasterns, and base-narrow toe-in or base-wide toe-out conformations. Direct trauma to this area can also lead to the development of ringbone. Ringbone usually occurs in the older horse unless it is due to trauma.

Ringbone typically causes heat, swelling, and pain. Lameness may not be seen in mild cases but is usually seen if the joint itself is also affected. It is hard to resolve the bony production of the joint because of the constant trauma and strain placed on the tendons and ligaments. Initially, treatment is rest and hydrotherapy to try to decrease the pain and swelling. Treatment then generally involves fusing the joint since these are low-motion joints. The earlier treatment is initiated, the better the prognosis. If the joint is affected, the horse often progresses to degenerative joint disease and the prognosis is poor.

Scratches. Scratches or grease heel (see Figure 7-1) is a low-grade infection or scab in the skin follicles around the fetlock. It is caused by filthy stables and unsanitary conditions. Response to cleanliness and treatment is usually prompt and complete.

Shoe Boil. Shoe boil (see Figures 7-1 and 7-3) is seen mostly in horses that are stabled and lie down for extended periods of time. The horse lies with the foot tucked up against the elbow. This irritates the elbow from the trauma of being hit by the foot. The result is a swelling at the point of the elbow, which is also called capped elbow.

Lameness is uncommon, and a shoe boil is usually just a blemish. The treatment is aimed at trying to reduce the swelling. Hydrotherapy and medicines to reduce the swelling are commonly used. Fibrosis, a thickening of the affected skin, may develop in chronic cases. This may leave a permanent blemish but usually does not affect the performance of the horse. If the boil occurs because of the shoe striking the elbow when lying down, a shoe boil roll or a boot can be applied to prevent the foot from injuring the elbow.

Sidebones. This is a common unsoundness resulting from wear, injury, or abuse. On each side of the heel extending above the hoof are elastic cartilages just under the skin that serve as part of the shock-absorbing mechanism. They are commonly termed lateral cartilages. When they ossify (turn to bone) they are called sidebones (see Figures 7-1 and 7-3). In the process of ossification they may be firm but movable inward and outward by the fingers. The horse is then considered "hard at the heels." Sidebones are more common to the front outside lateral cartilage than to other locations.

Splints. These are inflammations of the interosseous ligament that holds the splint bones to the cannon bone (see Figures 7-1 and 7-3). They are most common on the forelimbs and usually occur on the inside of the leg. Splints most commonly occur at the top of the splint bones, below the knee. They may also occur at the middle or end of the cannon bones. Splints are usually associated with conformation problems such as bench knees that place increased stress on the inside of the legs, trauma, or hard training. Trauma usually occurs due to slipping, being kicked, jumping, and playing hard.

Splints are seen most in horses 2 to 3 years old. Older horses can "throw" splints from overwork. Damage to the interosseous ligament causes it to swell. The degree and size of the swelling is directly related to the area that is injured. Other signs include inflammation, pain, and swelling associated with the early splint. Lameness is often present at the trot or faster gait in the early stages, but it depends on the extent of the splint.

A horse with splints should be rested, given hydrotherapy, and possibly receive other medications to reduce the size of the splint. The ligament heals by calcification of the injured area. The result is a bony area after healing that becomes a blemish. The calcification in the healing process may also intrude on the tendons in the back of the leg. This occurs most commonly when the splint is at the end of the splint bone.

If the pain seems intense or if the pain and swelling do not decrease, the splint bone actually may have fractured and injured the tendons in the back of the leg. X-rays can be used to verify the problem.

Stifled. Stifled (see Figure 7-3) refers to a displaced patella of the stifle joint. It sometimes cripples the horse permanently.

Stringhalt. Stringhalt, also called stringiness or crampiness, is considered an unsoundness. It is an ill-defined disease of the nervous system characterized by sudden lifting or jerking upward of one or both of the hind legs. Stringhalt is most obvious when the horse takes the first step or two (Figure 7-11).

Sprain. A sprain refers to any injury to a ligament. It usually occurs when a joint is carried through an abnormal range of motion such as in splints.

Thoroughpin. This is a soft, fluctuating enlargement located in the hollows just above the hock. They can be pressed from side to side, hence the name. Thoroughpins (see Figure 7-3) are due to a distention of the synovial bursa and considered a discrimination.

Thrush. Thrush is an inflammation of the fleshy frog of the foot. It is blackish in color, foul smelling, and associated with filthy stalls. It may cause lameness. Response to cleanliness and treatment is usually prompt and complete.

Upward Fixation of the Patella. This occurs when the patella is moved above its normal position and locks into place. It prevents the horse from flexing its stifle, and the stifle and hock are extended. The horse will drag its leg since it cannot flex it and bring it back under the body. The young horse may outgrow this problem. In the older horse, the knee may be popped backed into place, but this must be done carefully and correctly. Surgery can be done if this becomes a recurring problem.

Upward fixation of the patella is thought to be an inherited problem due to a straighthocked conformation. The hock and stifle are straighter than desired. Upward fixation of the patella may also be seen in the poorly muscled horse. Conditioning may be enough to stop the problem in this case.

Wind Puffs. Wind puffs, windgalls, or road puffs (see Figure 7-3) are soft enlargements located at the ankle joints and due to enlargement of the synovial (lubricating) sacs.

[FIGURE 7-11 OMITTED]

STABLE VICES AFFECTING USEFULNESS

Although they are not really an unsoundness or blemish, vices affect the usefulness, desirability, and value of horses. Vices are habits acquired by some horses that are subjected to long periods of idleness. Hard work and freedom from close confinement are distinct preventives. Bad habits should be corrected or prevented early before they become confirmed.

Wind-sucking, cribbing, weaving, and stall-walking horses are hard to keep in condition. And the latter two vices cause horses to be fatigued when they are needed.

Wind-sucking

A wind-sucking horse identifies an object on which it can press its upper front teeth while pulling backward and sucking air into the stomach, usually accompanied by a prolonged grunting sound. The habit is practiced while eating, thus causing loss of food. Confirmed wind-suckers will identify an object in the pasture on which to suck wind, and will practice the habit when tied with bridle or halter as the opportunity is presented.

Cribbing (crib biting)

Cribbing horses (Figure 7-12) grasp an object (edge of a feed box or manger) between their teeth and apply pressure, gradually gnawing the object away if it is not metal. Wind-sucking and cribbing are usually associated, although a horse may practice one without the other. Cribbing wears away the teeth to a point of decreased efficiency when grazing. Both habits may be partially prevented and sometimes stopped by a wide strap fitted sufficiently close about the throat to compress the larynx when pressure is borne on the front teeth. Normal swallowing is not impaired. The strap must be placed with care; it should be loose enough to prevent choking and tight enough to be effective.

Weaving

Weaving is a rhythmical shifting of the weight from one front foot to the other. It is not a common vice, but when carried to extremes it renders a horse almost useless. Its cause is obscure, but its occurrence is correlated with enforced idleness in confined quarters. Some horse owners condemn vertical bars that can be seen through; others consider chain halter shanks, which rattle when moved, as predisposing causes.

[FIGURE 7-12 OMITTED]

Stall Walking

Stall walking is just what it sounds like. It is uncommon but reduces a horse's condition and induces fatigue.

Kicking

Occasionally horses will learn to destroy partitions or doors in stalls by kicking. Some kick only at feeding time, to vent their impatience. They usually do not kick outside the stall. Padding the stall has been known to stop some kickers.

Biting

Stallions often acquire the habit of nipping at the attendant just for something to do. Gentle horses can be encouraged to nip when too much pressure is applied in grooming or during cinching the saddle girth. Many show horses use biting to defend themselves when agitated by pokes from well-wishers as they rest in their stalls on the show circuit. Removing the cause usually corrects the condition.

Tail Rubbing

Tail rubbing starts by agitation from parasites and continues from habit. Parasite control and tail boards prevent it.

Halter Pulling

Halter pulling develops when a horse becomes confident that it is stronger than the rigging that secures it. Young horses in training will not gain such confidence when secured by strong halter equipment tied to stationary objects. Bridles should not be used in tying young horses. The habit may be broken in early stages by a slip noose around the flank, with the rope shank passing between the forelegs, through the halter ring, and being fastened securely. Pain experienced by the horse from hard backward pulling is usually given consideration before tightening a halter shank afterward. A second rather successful method is to pass the halter rope through a tie ring in the stall and fasten it to a hobble placed on a fore pastern.

EXAMINING HORSES FOR SOUNDNESS

Accurately diagnosing a horse's soundness is never easy. Sometimes professional assistance is needed. Whenever possible, a potential buyer should take the horse on a trial basis for use under the conditions to which it will be subjected under new ownership. Some guarantees of soundness are useful. Most horse owners can increase their competence in identifying unsoundness and blemishes by practice and by using a system of inspection (Figure 7-13).

Natural Surroundings

Whenever possible, examine the horse in its stall under natural surroundings. Note the manner of tying--the horse may be a halter puller. If metal covers the manger or feed box, cribbing should be suspected. Look for signs of a strap around the throat latch. Note the arrangement of bedding. If the horse paws, bedding will be piled up near its back feet. Slight lameness may be detected by movement of bedding caused from pointing. Signs of kicking may be noted. Move the horse around and observe signs of slight founder, stiffness, crampiness, and stable attitude.

[FIGURE 7-13 OMITTED]

Leading

Lead the horse from the stall, and observe the eyes closely for normal dilation and color. Test eyesight further by leading the horse over obstacles such as bales of hay, immediately after coming out of the stall into brighter light. Back the horse and observe hock action for stringhalt and crampiness. Stiff shoulders and/or stiff limbs are indicated by a stilted, sluggish stride.

In Motion

Examine the horse for lameness in motion. Lameness in a forelimb is indicated by a nod of the head when weight is placed on the sound limb. The croup drops when weight is shifted from a lame hind limb to a sound one. Splint lameness usually gets worse with exercise, whereas spavin lameness may improve. The horse should be examined when cool, when warmed up, and when cooled off again, at both the walk and trot. Soundness of wind should be checked under conditions of hard work. Be alert for roaring and heaves or the appearance of a discharge from the nose. Cocked ankles may appear after sharp exercise, and weak fetlocks and knees may tremble.

Overall

Make a general examination with the horse at rest. It should not point or shift its weight from one forelimb to the other. Stand directly in front of the horse and observe the eyes for signs of cloudiness, position of the ears for alertness, and scars or indentations indicating diseased teeth. Pay particular attention to the knees, cannons, and hoof heads for irregularities. Move to the side at an oblique angle and note strength of back and coupling, signs of body scars, and shape and cleanness of hocks, cannons, fetlocks, and hoof heads.

Look for capped hocks, elbows, and leg set from a side view. Chin the horse at the withers for an estimation of height. Stand behind the horse and observe symmetry of hips, thighs, gaskins and hocks, and position of the feet. Move to the opposite side and the oblique angle previously described for final visual inspection before handling any part of the horse.

Determine age according to the instructions in Chapter 9.

The wall of a good hoof is composed of dense horn of uniform color with no signs of cracks in it or rings around it. The slant of the toe should be about 45 degrees and should correspond with that of the pastern. The heels should be deep and reasonably wide. Pick up each foot and look at the bearing surface. The frog should be full and elastic and help bear weight. The bars should be large and straight. The sole should be arched and should not appear flat as in dropped sole. Check for hard heels or sidebones, ringbone, corns, contracted feet, and thrush. If the horse is shod, check for wear on the shoe from contraction and expansion of healthy heels.

Examine the hocks for swellings, spavins, puffs, curbs, or other irregularities, by feeling when necessary.

A thorough examination combined with a week's trial will identify almost any unsoundness or blemish. Many horses serve faithfully for a lifetime without developing unsoundness, vices, or bad manners. Such service can come to horse owners only through patience, knowledge, and detailed attention to the needs of the animal.

SUMMARY

Some horses become unsound at an early age because of coarse, crooked legs, whereas others remain useful for years. As with cars, abusive treatment, excessive use, and poor care will render any horse unsound. Unsoundness interferes with the performance of the horse. A blemish is unsightly, but it is not apt to influence the horse's performance. An evaluation of an unsoundness or blemish is influenced by how the horse is used, for example, pleasure versus competition. Many conditions leading to an unsoundness or blemish are preventable or treatable. The prognosis for treatment can also depend on the intended use of the horse. Unsoundnesses and blemishes can be found on any part of the body. For obvious reasons, those of the limbs are the most common.

Unsoundnesses and blemishes decrease the value and may alter the use of a horse. Stable vices may also decrease the value and use of a horse. Using a methodical inspection, unsoundnesses, blemishes, and stable vices can be spotted in an unknown horse.

REVIEW

Success in any career requires knowledge. Test your knowledge of this chapter by answering these questions or solving these problems.

True or False

1. A blemish will always interfere with the performance of a horse.

2. Poor conformation has little to do with unsoundness.

3. Unsoundness interferes with the function and performance of a horse.

4. Thrush is caused by unclean stables.

5. Quittor is the name for horses dropping feed out of their mouth while they are chewing.

Short Answer

6. Name six stable vices that can affect the use and value of a horse.

7. An unsoundness of the lungs or respiratory tract includes --, a partial paralysis of the nerves to the muscles of the vocal cords, and --, a loss of elasticity in the lungs.

8. Name two types of sprains and two types of fractures.

9. List four unsoundnesses associated with the head of the horse.

10. List five common unsoundnesses or blemishes that can be found on the body of a horse.

11. List four blemishes of the limbs.

12. Name six unsound conditions of the limbs.

13. Give two conditions caused by unclean stables.

Critical Thinking/Discussion

14. Describe the difference between a blemish and an unsoundness.

15. What is the common treatment for an injury that could develop into an unsoundness?

16. Identify four conditions that could predispose a horse to developing an unsoundness.

17. Briefly describe a system of inspection to check unknown horses for unsoundness, blemishes, and possible stable vices.

18. Describe the cause, diagnosis, and possible treatment of bucked shins, chip fractures, osselets, quarter cracks, and ringbone.

STUDENT ACTIVITIES

1. Visit a veterinarian's office or invite a veterinarian to class. Ask the veterinarian to show and explain some X-rays of bone injuries.

2. Develop a report or presentation on new technologies used to treat leg fractures in horses.

3. Diagram the bones of the front or hind leg of a horse. Indicate on the diagram where an unsoundness can develop. Use the unsound conditions discussed in this chapter.

4. Visit a farrier or invite a farrier to class. Ask the farrier to describe how shoeing can correct some conformation problems and unsoundnesses.

5. View a video on conformation and/or lameness selected from the list in the Additional Resources section of this chapter.

6. Visit with a horse breeder and determine the most common types of blemishes and unsoundnesses.

7. Tape small blocks of wood on your shoes and try to walk. Describe the direction that it turns your feet. Compare this to how a good farrier can correct feet and leg problems through corrective trimming.

ADDITIONAL RESOURCES

Books

Evans, J. W. (2000). Horses: A guide to selection, care, and enjoyment (3rd ed.). NewYork: Owl Books.

Frandson, R. D., Fails, A. D., & Wilke, W. L. (2003). Anatomy and physiology of farm animals. (6th ed.) Philadelphia: Lippincott Williams & Wilkins.

Griffin, J. M., & Gore, T. (1989). Horse owner's veterinary handbook (2nd ed.). New York: Howell Book House.

Kahn, C. M. (Ed.). (2005). The Merck veterinary manual (9th ed.). Whitehouse Station, NJ: Merck & Co.

Kainer, R. A., & McCracken, T. O. (1998). Horse anatomy: A coloring atlas. (2nd ed.). Loveland, CO: Alpine Publications.

Siegal, M. (Ed.) & School of Veterinary Medicine. (1996). Book of horses: A complete medical reference guide for horses and foals. New York: HarperCollins.

Internet

Internet sites represent a vast resource of information, but remember that the URLs (uniform resource locator) for World Wide Web sites can change without notice. Using one of the search engines on the Internet such as Yahoo!, Google, or About.com, find more information by searching for these words or phrases:

conformation

leg fractures

horse unsoundness

horse blemishes

hydrotherapy

founder

laminitis

navicular disease

sprain

stable vices

Table A-18 in the appendix also provides a listing of some useful Internet sites that can serve as a starting point for further exploration.
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Author:Parker, Rick
Publication:Equine Science, 3rd ed.
Date:Jan 1, 2008
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Previous Article:Chapter 6 Biomechanics of movement.
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