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Laminitis
Prevention and Treatment
Every day
veterinarians across the country see hundreds of cases of laminitis, a painful
disease which affects the horse's feet. What's especially alarming is that
some cases are preventable. In fact, it may be that we are killing our
horses with kindness.
Consider that a common cause of laminitis is overfeeding - a
management factor that is normally within our control.
By learning more about laminitis, its causes, signs and
treatments, you may be able to minimize the risks of laminitis in your horse, or
control the long-term damage if it does occur.
LAMINITIS DEFINED
Laminitis
results from the disruption (constant, intermittent, or short-term) of blood
flow to the sensitive or insensitive laminae. These laminae structures
within the foot secure the coffin bone (the wedge-shaped bone within the foot)
to the hoof wall. Inflammation often permanently weakens the laminae and
interferes with the wall/bone bond. In severe cases, the bone and the hoof
wall can separate. In these situations, the coffin bone may rotate within
the foot, be displaced downward ("sink") and eventually penetrate the sole.
Laminitis can affect one or all feet, but is most often seen in the front feet
concurrently.
The terms
"laminitis" and "founder" are used interchangeably. However, founder
usually refers to a chronic (long-term) condition associated with rotation of
the coffin bone. Whereas, acute laminitis refers to symptoms
associated with a sudden initial attack, including pain and inflammation of the
laminae.
CAUSES
While the exact
mechanisms by which the feet are damaged remain a mystery, certain precipitating
events can produce laminitis. Although laminitis occurs in the feet, the
underlying cause is often a disturbance elsewhere in the horse's body. The
causes vary and may include the following:
-
Digestive upsets due to grain
overload or abrupt changes in diet
-
Sudden access to excessive
amounts of lush forage before the horse's system has had time to adapt, this
type of laminitis is known as "grass founder"
-
Toxins released within the
horse's system
-
High fever or illness; any
illness that causes high fever or serious metabolic disturbances has the
potential to cause laminitis, e.g., Potomac Horse Fever
-
Severe colic
-
Retained placenta in the mare
after foaling
-
Consumption of cold water by an
overheated horse
-
Excessive concussion to the
feet, often referred to as "road founder"
-
Excessive weight bearing on one
leg due to injury of another leg or any other alteration of the normal gait
-
Various primary foot diseases
-
Bedding that contains black
walnut shavings
-
Prolonged use or high doses of
corticosteroids
RISK FACTORS
Factors that
seem to increase a horse's susceptibility to laminitis or increase the severity
of the condition when it does occur include the following:
-
Heavy breeds, such as draft
horses
-
Overweight
-
High nutritional plane
-
Ponies
-
Unrestricted grain binges, such
a when a horse breaks into the feed room (If this happens, do not wait
until symptoms develop to call your veterinarian. Call immediately
so corrective action can be taken before tissue damage progresses.)
-
Horses who have had previous
episodes of laminitis
SIGNS
Signs of
acute laminitis include the following:
-
Lameness, especially when a
horse is turning in circles
-
Heat in the feet
-
Increased digital pulse in the
feet
-
Pain in the toe region when
pressure is applied with hoof testers
-
Reluctant or hesitant gait
("walking on eggshells")
-
A "sawhorse stance", with the
front feet stretched out in front to alleviate pressure on the toes and the
hind feet "camped out" or positioned further back than normal to bear more
weight
Signs of
chronic laminitis may include the following:
-
Rings in hoof wall that become
wider as they are followed from toe to heel
-
Bruised soles or "stone
bruises"
-
Widened white line, commonly
called "seedy toe", with occurrence of seromas (bloody pockets) and/or
abscesses
-
Dropped soles or flat feet
-
Thick, "cresty" neck
-
Dished hooves, which are the
result of unequal rates of hoof growth (The heels grow at a faster rate than
the rest of the hoof, resulting in an "Aladdin-slipper" appearance.)
TREATMENT
The sooner
treatment begins, the better the chance for recovery. Treatment will
depend on specific circumstances but may include the following:
-
Diagnosing and treating the
primary problem (Laminitis is often due to a systemic or general problem
elsewhere in the horse's body.)
-
Dietary restrictions
-
Treating with mineral oil, via
a nasogastric tube, to purge the horse's digestive tract, especially if the
horse has overeaten
-
Administering fluids if the
horse is ill or dehydrated
-
Administering other drugs, such
as antibiotics to fight infection, anti-endotoxins to reduce bacterial
toxicity; anticoagulants and vasodilators to reduce blood pressure while
improving blood flow to the feet (Corticosteroids are contraindicated in
laminitis, as they can actually cause laminitis or exacerbate existing
cases.)
-
Stabling the horse on soft
ground, such as in sand or shavings (not black walnut), and encouraging the
horse to lie down to reduce pressure on the weakened laminae
-
Opening and draining any
abscesses which may develop
-
Cooperation between your
veterinarian and the farrier (Techniques that may be helpful include
corrective trimming, frog supports, and therapeutic shoes or pads.)
LONG-TERM OUTLOOK
Many horses that
develop laminitis make uneventful recoveries and go on to lead long, useful
lives. Unfortunately, others suffer such severe, irreparable damage that
they are, for humane reasons, euthanized.
Your equine
practitioner can provide you with information about your horse's condition based
on radiographs (x-rays) and the animal's response to treatment. Radiographs will
show how much rotation of the coffin bone has occurred. This will help you
make a decision in the best interest of the horse and help the farrier with
the therapeutic shoeing.
The nail is a marker to show the outside of the
hoof wall which aids in determining if the coffin bone has rotated. The tack in
the bottom of the foot is a marker to aid in determining if the coffin bone has
sunk. This is a relatively normal looking foot.
In this particular horse there is a
15 degree rotation of the coffin bone from the hoof wall.
In this radiograph, the coffin bone
has extreme rotation and is also sinking through the sole of the hoof.
MANAGEMENT
Importantly,
once a horse has had laminitis, it may be likely to recur. In fact, a
number of cases become chronic because the coffin bone has rotated within the
foot and because the laminae never regain their original strength. There
may also be interference with normal blood flow to the feet, as well as
metabolic changes within the horse. Extra care is recommended for any
horse that has had laminitis, including:
-
A modified diet that provides
adequate nutrition based on high-quality forage and without excess energy,
especially from grain
-
Routine hoof care, including
regular trimming and, in some cases therapeutic shoeing (Additional
radiographs may be needed to monitor progress.)
-
A good health-maintenance
schedule, including parasite control and vaccinations to reduce the horse's
susceptibility to illness or disease
-
Possibly a nutritional
supplement formulated to promote hoof health
SUMMARY
The best way to
deal with laminitis is preventing the causes under your control. Keep all
grain stored securely out of the reach of horses. Introduce your horse to
lush pasture gradually. Be aware that when a horse is ill, under stress or
overweight, it is especially at risk. Consult your equine practitioner to
formulate a good dietary plan. Provide good, routine health and hoof care.
If you suspect laminitis, consider is a medical emergency: Notify your
veterinarian immediately.
This information was provided
by the American Association of Equine Practitioners.
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