Evaluating The
Lame Horse
Stress, strain, or injury can
take a toll on any horse, even one with no obvious conformation defects. When
lameness occurs, you should contact your Veterinarian promptly. A prompt examination
can save you time, money, and frustration by diagnosing and treating the problem
immediately, possibly preventing further damage. The goal of such early examinations
is to keep small problems from becoming big ones.
Lameness evaluations are also routine
in most purchase examinations. When your veterinarian evaluates an animal you
are considering for purchase, you may be forewarned about potential problems
and should be able to make a more informed decision.
LAMENESS DEFINED
Lameness is any alteration of the
horse's gait. Such abnormalities can be caused by pain in the neck, withers,
shoulders, back, loin, hips, legs, or feet. Identifying the source of the problem
is essential to proper treatment.
EXAMINATION PROCEDURES
Veterinarians have specific systems
far performing examinations, depending on the reasons for the evaluation. However,
essential features of a thorough examination include:
- The medical history of the horse. The
veterinarian asks the owner questions relating to Past and present difficulties
of the horse. He or she also inquires about exercise or work requirements and
any other pertinent information. A visual appraisal of the horse at rest. The
veterinarian will study conformation, balance, and weight bearing, and look for
any evidence of injury or stress. Evaluation of the horse in motion. The
veterinarian watches the horse walking and trotting. Observing the horse from
the front, back, and both side views, the veterinarian notes any deviations in
gait (such as winging or paddling), failure to land squarely on all four feet,
and the unnatural shifting of weight from one limb to another. The horse also
walks and trots in circles, on a long line, in a round pen, and under saddle.
The veterinarian looks for signs, such as shortening of the stride, irregular
foot placement, head bobbing, stiffness, weight shifting, etc. A thorough
hands-on exam. The veterinarian palpates the horse, checking muscles, joints,
bones, and tendons for evidence of pain, heat, swelling, or any other physical
abnormalities. Application of hoof testers to the feet. This instrument
allows the veterinarian to apply Pressure to the soles of the feet to check for
undue sensitivity or pain. Joint flexion tests. The veterinarian holds
the horse's limbs in a flexed position and then releases the leg. As the horse
trots away, the veterinarian watches for signs of pain, weight shifting, or irregular
movement. Flexing the joints in this manner may reveal problems not otherwise
readily apparent.
- Drug test. Blood tests can
be done to detect drugs that may camouflage lameness.
DIAGNOSTIC TESTS
Diagnostic procedures are often
necessary to isolate the specific location and cause of lameness. Lameness cannot
be effectively treated without a specific diagnosis. If your Veterinarian has
cause for concern based on initial examination, he or she may recommend further
tests, including radiographs, diagnostic nerve block, nuclear scanning, arthroscopy,
ultrasound, and examination of blood, synovial fluid, and tissue samples.
- Radiographs. X-rays are
useful in identifying damage or changes to bony tissues. Radiographs should be
interpreted only by an experienced and knowledgeable veterinarian, since not
all changes are cause for concern. Radiographs provide limited information about
soft tissue, such as tendons, ligaments, or structures inside the joints, which
are often the source of lameness. Diagnostic nerve and joint blocks. These
analgesic techniques are perhaps the most important tools used to identify the
location of lameness. Working from the foot up, the veterinarian temporarily
deadens sensation to specific segments of the limb, one joint at a time, until
the lameness disappears. This procedure isolates the area of pain causing the
lameness. Blocks can also help determine whether the condition is treatable. Scintigraphy
(Nuclear scanning). Radioisotopes injected intravenously into the horse are
concentrated in inflamed areas. These areas can be scanned with a gamma camera,
providing an image of the trouble site. Arthroscopy. This procedure allows
optical examination of internal joint tissues or tendon sheaths. It requires
general anesthesia but may be the only way to define the damage. Some diagnoses
can only be made with arthroscopy. Ultrasound (Sonography). This procedure
uses ultrasonic waves to image internal structures.
-
Blood, synovial
(joint) fluid, and tissue samples. These samples can be examined for infection
or inflammation. Such examinations usually require laboratory testing.
AAEP LAMENESS
SCALE
Because each horse
has unique performance characteristics, evaluating lameness can be challenging.
Experienced riders may detect minor alterations in gait before they are apparent
to an observer. Lameness may appear as a subtle shortening of the stride, or
the condition may be so severe that the horse will not bear weight on the affected
limb. With such extremes of lameness possible, a lameness
grading system has been developed by the AAEP to aid both communication and record-keeping.
The scale ranges from zero to five, with zero being no perceptible lameness,
and five being most extreme. The AAEP guidelines explain
the grading system this way:
- Lameness not perceptible
under any circumstances. Lameness is difficult to observe
and is not consistently apparent, regardless of circumstances (e.g., weight carrying,
circling, inclines, hard surface, etc.) Lameness is difficult
to observe at a walk or when trotting in a straight line but consistently apparent
under certain circumstances (e.g., weight carrying, circling, inclines, hard
surface, etc.) Lameness is consistently observable at
a trot under all circumstances. Lameness is obvious at
a walk.
- Lameness produces
minimal weigh bearing in motion and/or at rest or a complete inability to move.
MORE ABOUT OBSERVING THE HORSE
IN MOTION
The veterinarian
should observe the horse on both soft and hard surfaces, since different types
of lameness may become apparent with different footing. In addition, lameness
may only be apparent when the horse is under saddle, or it may be manifest only
at liberty or on a long line when the horse can be evaluated without the influence
of the rider.
A horse's walk and
trot may be especially revealing.The slower gait of the walk makes it easier
to observe slight deviations that aren't readily apparent at a faster pace. However,
the trot is perhaps most useful for evaluating lameness because it is the simplest
gait, consisting of a two-beat stride pattern, and because the horse's weight
is distributed evenly between diagonal pairs of legs. The speed and concussion
of a faster pace may help elicit pain, but identification of the affected limb
is facilitated by the slower gaits.
LAMENESS EVALUATIONS IN RELATION
TO PURCHASE EXAMS
Evaluation for the
presence of lameness should be part of every purchase evaluation. While it is
impossible to predict a horse's actual performance, the veterinarian can provide
information regarding lameness or potential lameness by evaluating conformation,
movement, medical history, past performance, and existing medical conditions.
The extent of the exam will be determined by the buyer and veterinarian. Value,
intended use, and long-term goals may be factors in selecting certain exam procedures.
For example, radiographs, sonograms, and other diagnostic tests provide comprehensive
pictures of the horse's condition, but they also add to the exam's cost. The
most important question your veterinarian will ask is: What will you be doing
with this horse?
Your veterinarian
will then weigh conformation, movement, and medical considerations against the
type and level of performance expected, A horse that is fine for a daily pleasure
ride may not hold up under more strenuous activities.
LAMENESS EVALUATION
In the purchase lameness
exam, the veterinarian will try to determine two things: 1)
Is the horse lame at the present time, or are there existing conditions that
deserve a closer look? 2) What is the likelihood that
the horse will remain serviceable for its intended use? Age, health, expected
level of activity, conformation, and past use will be considered.
The veterinarian
will inform the owner of the relevant facts and risks, and the owner can then
decide whether to Purchase the horse.
LIMITATIONS OF PURCHASE EXAMS
It is important to
remember that even a favorable report following a lameness exam does not guarantee
there are no problems. Many factors can affect a horse's short and long-term
ability to perform. Factors in the lameness equation include many variables,
such as:
- Conformation Hoof
care Use of protective leg gear Fitting
and conditioning of the horse Degree
and manner of training Type and level of performance Age Skill,
balance, and experience of the rider Type or condition
of the sound on which the horse performs Disease or injury Genetic
predisposition
- Others
In order for your
veterinarian to evaluate a horse fairly, the animal should be fit, conditioned,
and in training for its intended use. A horse that has been laid off for an extended
time will be difficult to evaluate for lameness. One option may be to ask that
the horse be returned to training and then re-examined after 30-60 days. Depending
on the horse's value, such a request may be reasonable. Ask your veterinarian. GOOD
STEWARDSHIP  Lameness
is a complicated condition, With many possible causes. Be a conscientious observer.
If you suspect a problem, discontinue riding your horse and seek advice from
your veterinarian promptly.
By identifying even a minor lameness and acting swiftly to correct it, you will
minimize the risk of injury to the horse and yourself, and you will be rewarded
by better performance and a longer useful life from your horse.
This
brochure was developed By the American Association of Equine Practitioners through
a grant from Bayer Corporation, Animal Health.
©1995 Bayer Corporation
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