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| Blood Loss in
Horses |
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Equine
veterinarians are always getting calls about horses with
cuts. Often the owner
is very concerned over the amount of blood that may have been
lost. It takes very little blood on the ground to look like a
bucket's worth. Usually by the time I arrive, the horse that
the owner thought was bleeding to death is quietly eating, and
the bleeding has stopped on its own. |
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The
word hemostasis means stopping blood flow. Horses
have an unusually good hemostatic system and even large
diameter blood vessels that have been sliced will retract
back into tissue and seal themselves off. Another hemostatic
feature in horses is the huge reserve of red blood cells
in the spleen. Within seconds of excitement from any source,
adrenalin is released. The adrenalin causes the spleen to contract,
sending out pints of red cell rich blood. Horses also form
good blood clots which further slows the hemorrhage. |
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In
a horse losing quantities of blood other changes
are occurring to maintain blood pressure. Fluid is pulled
from the spaces between the cells of the body and is shifted
into the blood vessels. Arteries supplying non essential
areas constrict. This keeps most of the blood going to
vitally important structures like the brain and the heart.
That shift results in a lower body temperature and cold skin.
The heart rate increases to pump around the now decreased volume
of blood. However, if enough blood has been lost, the emergency
measures will start to fail, and the animal will go into shock. |
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There
is a rough rule to determine how much blood a horse has. Depending
on the breed you can estimate that 6-10% of the body weight
is blood. (Arabians and Thoroughbreds would be the highest,
draft horses the lowest). A 1000 lb. Thoroughbred would
have about 100 pounds or roughly 100 pints (50 quarts)
of blood. In my research I found that a horse can lose
up to 30% of its blood (in this case 15 quarts! ) and still
live. In over 30 years of experience I have never seen
a horse bleed to death from a laceration. |
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If
your horse has been cut and is bleeding profusely, don't move
him. Check his temperature, pulse and respiration.
Roll back his lip and check for extreme paleness. Call us.
Be ready to describe exactly where the cut is and how deep.
Estimate unemotionally how much blood is on the ground. Now
with a clean piece of cloth apply firm steady pressure directly
over the wound. Maintain that pressure for at least five
minutes. Remove the pressure slowly. If the bleeding continues,
reapply the pressure and double the time. Don't worry about
scarring. Most sutured lacerations in horses do not leave
a scar. Above all, don't panic. The blood system has plenty
of built in reserves, or as the old horsemen used to say, “It's
a long way from his heart.” |
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| David A. Jefferson, D.V.M. 2006 |
New
Gloucester, Maine 04260