Page 133 - February 2016 Speedhorse

fever of 105 or higher, my first thoughts for possible causes
would include strangles, Anaplasma, Potomac Horse Fever (the latter two caused
by rickettsial organisms) and some of the viruses (like equine influenza),” she says.
“Another instance in which we might see high fever is when a horse gets
endotoxemia, which is not an infection, per se. Horses are
uniquely sensitive to endotox- ins, which are part of the cell wall of certain bacteria. There
are a lot of these bacteria inside the horse’s intestine just because bacteria are normal inhabitants of the intestine.
Many of the gram-negative bacteria live and die there and go through their life cycle in the colon. When a horse has colitis (inflammation of the colon), some of the endotoxin from the bacteria’s dead cell walls may leak through the colon lining into the bloodstream. This causes a very dramatic cytokine response and fever.” This is not an infection, but is a very damaging toxic condition in which the body has an over- reaction to the dead bacterial components.
The horse continues to have a fever until the body starts winning the battle against whatever problem it has been fighting. To know how best to treat the horse, however, we need to know which disease to target.
“The veterinarian will usually do a physical exam of the horse. If there are swollen lymph nodes under the jaw or thick nasal discharge, this would make us suspect strangles. If the horse has a cough or abnormal lung sounds we will suspect a virus or pneumonia. With Potomac Horse Fever, we would probably see diarrhea or signs
of laminitis. If the horse has a colic in which the
A horse that has a fever along with swollen lymph nodes under the jaw or thick nasal discharge would indicate the horse may have strangles.
The important thing for horse owners to remember is that there is usually nothing particularly dangerous about the fever itself.
intestine is twisted, we may see endotoxemia and high fever along with severe colic pain. Horses with anaplasmosis may have a high fever with no other signs except maybe some mild swelling of the legs,” says Nolen-Walston.
The veterinarian generally does blood work
to confirm or rule out the suspected disease. “The lab results will frequently help us determine which of those potential causes it is,” she explains.
WHEN AND HOW TO REDUCE A FEVER
After a proper diagnosis, an effective treatment can be started. Sometimes this will include strategies to reduce the fever. Many horse owners worry about a high fever and want to do something to treat the fever as well
as the actual disease. “Fever in itself is usually not a problem in horses. In humans, we don’t start seeing brain damage until fever gets up above 107 degrees. We almost never see brain damage from fever in horses. The important thing for horse owners to remember is that there is usually nothing particularly dangerous about the fever itself,” she says.
“Most of the time we treat a fever, however, because a horse with a fever feels miserable and won’t eat or drink. There’s not a general rule on when to treat the fever because every horse is different regarding whether and when he might not feel good, but usually I would treat the fever if it gets above 104 or 104.5. Most horses will not feel good when it gets this high. If
Temporary High Temperature From Heat And Exercise
If a horse is hot after exerting in hot weather, the best way to deal with it is
by bathing the horse with cool water and making sure he has access to plenty of water to drink. “Horses with anhidrosis (inability to sweat) can get dangerously high body temperatures because the main way that they reduce heat is through sweating. Horses don’t pant like a dog,
so they must be able to sweat,” says Nolen-Walston.
• Cool water baths are more effective for reducing high temperature due to exercise in hot weather (or inability to sweat) since the horse’s set point has not changed—and body temperature will return to normal— than for reducing a true fever. When the horse’s set point is increased due to illness, the cold water may just make the body work harder to produce more heat to keep the temperature at a higher level. It may
be more important to help him fight the disease rather than try to lower the fever, so consult your veterinarian.
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EQUINE HEALTH