Abscess Distress
Rebecca Colnar

My first experience with hoof abscess came a few days after I
bought my thoroughbred mare at the track. I went to the barn one
morning to find her dead lame, unable to place any weight on her
back hoof. I feared the worst. Did she possibly have an existing
injury I wasn't told about?

Instead, my vet said her acute lameness was a hoof abscess.

After this happened a couple of other times with her, I could
diagnose the problem on my own. She'd be very lame for a day or
two, then she'd be fine, and she wouldn't go lame again for
another year.

Veterinarian Steve O'Grady of Virginia Equine Podiatry Center,
confirmed what I had learned the hard way: hoof abscess is a
common cause of acute lameness.

Abscesses occur when foreign matter, commonly called "gravel,"
gains entry into the hoof through the sole-wall junction, or
white line, explains O'Grady.

"The debris will migrate in the hoof to the laminae, the
sensitive tissue above the horse's sole, leading to an infection.
The other common cause of subsolar abscess is penetration of the
bottom of the foot--usually the sole or frog--by a sharp object."
O'Grady adds that infection may also gain entry into the foot via
a hoof-wall crack.


An untreated abscess will follow the path of least resistance up
the hoof wall.


"Mechanical breaks or weakness in the white line can happen with
improper trimming (leading to hoof imbalance), hoof-wall
separations, aggressive removal of the sole during trimming, and
chronic laminitis," the veterinarian explains.

An untreated abscess will follow the path of least resistance up
the hoof wall and will form a draining tract at the coronet.

Most affected horses show sudden lameness, O'Grady says. "The
degree varies from subtle to non-weight bearing. The pulse at the
fetlock is usually pounding, and the foot with the abscess will
be warmer than the opposite foot."

The point of pain can be located using hoof testers. The wound or
point of entry may not always be visible since some areas of the
foot, such as the white line and frog, are somewhat elastic, and
wounds in these areas typically close.

"Sometimes pain will be noted over the entire foot. In this case
the veterinarian may want to check for a severe bruise or a
possible fracture of the coffin bone," he notes.

Treatments work best at the first sign of lameness, before the
gravel ruptures at the coronet. Treat a simple subsolar abscess
by opening and draining the infection. The opening should be
large enough to allow drainage, but not so extensive as to create
further problems.

Drainage can be speeded using a poultice for the first 48 hours.

"This often eliminates the need for continued foot soaking,"
O'Grady advises. "The hoof is kept bandaged with a suitable
antiseptic until all drainage has ceased and the wound has
closed.

At this point, a small gauze plug, held in place with glue, is
used to fill the opening. This keeps affected areas clean and
prevents the accumulation of debris in the wound." The shoe can
be replaced at this point.

If the pain can be located, but drainage cannot be established at
the white line, then the infection has migrated under the sole
away from the white line.

"Under no circumstances should an opening be created in the sole.
This will lead to a persistent, non-healing wound and more
susceptibility to bone infection," O'Grady cautions.

Instead, expect your vet to make a small channel in the subsolar
tissue leading to the infection.

Antibiotics are optional and based on the needs of the individual
horse. Your veterinarian may prescribe bute or some other
medication to ease the discomfort. "Your horse's lockjaw
immunization should be up to date," O'Grady notes.

Wrapping it up
Although abscesses sound like an equine hoof problem that "just
happens," they can be prevented, insists Dr. Steve O'Grady. "A
strong, solid white line which resists penetration by debris is
the best prevention," he says.

Farriery is a prime factor. "The hoof has a natural ability to
provide protection to the sole of the hoof. Enhance these strong
features through proper trimming," the vet insists. "Excessive
removal of the protective horn is a common practice when too much
emphasis is placed on eye appeal instead of functional
strength--not a good idea."

To prevent gravel, it is important for the foot to be trimmed to
preserve a strong healthy foot. Improperly trimmed feet can lead
to cracks and hoof wall separations--one of the most common
causes of hoof abscess.

Preventive maintenance in dry weather includes a hoof dressing
painted on the entire foot to contain moisture.

Too much moisture can also make a horse susceptible to hoof
abscesses. In extremely wet weather or when the horse is being
washed frequently during show season, consider hoof hardeners,
such as Keratix. Bedding on shavings or sawdust can also help.