Diseases and Disorders
A horse is susceptible to many diseases and disorders, especially those affecting respiration, circulation, and soundness of legs and feet. The most serious diseases of horses include anthrax; distemper (also called “strangles”), common among young animals; equine encephalomyelitis (“sleeping sickness,” called “encephalitis” in humans); equine infectious anemia (“swamp fever”), a disease of the blood caused by a virus; glanders, an infectious disease most commonly affecting the lungs; rabies; and tetanus (lockjaw). Other diseases include colds and equine influenza, dangerous primarily because they may lead to such complications as pneumonia.
Horses are subject to attack by about 150 different species of internal parasites. These include many kinds of intestinal worms and the larvae of such insects as the botfly. Common external parasites include blowflies and other flies, lice, ticks, and mites. Heavy infestation by internal or external parasites can greatly weaken a horse.
Disorders in structure or function include heaves, or pulmonary emphysema, a respiratory condition in which the horse has trouble forcing air out of its lungs. Colic (abdominal pain) is usually caused by a sudden change in feed or by the horse's eating too fast, working hard soon after eating, or drinking too much at once. A horse with colic may injure itself thrashing about in pain. Wounds, commonly caused by fights with other horses or encounters with barbed wire fences, are dangerous because of the possibility of infection.
Disorders of the legs and feet that can cause lameness include splints, abnormal growths on the cannon bone of the leg; bog spavin, an enlargement at the hock through accumulation of fluid; and bone spavin, a bony enlargement at the hock. Founder (laminitis) is a very serious and painful disorder that affects blood vessels in the foot and eventually causes the hoof to become deformed. It is caused by the horse's overeating, overworking, or drinking too much cold water when hot. Thrush is an infection of the frog (a structure on the bottom of the foot) caused by unsanitary conditions and lack of exercise; it can cause the animal to become lame.
Signs of illness in a horse include loss of appetite, lack of vigor (active physical strength), mucous or bloody discharge from the eyes or nose, swellings or sores on the body, and hot legs or feet. A fast or slow breathing rate or pulse rate may also be a sign of illness. Normally, a resting horse breathes from 8 to 16 times per minute and has a pulse rate of from 30 to 40 beats per minute.
One of the most common medical complaints horses suffer is colic. Colic is pain in the horse’s abdomen. It can be caused by a number of things, some very serious. Signs of colic can include sweating, loss of appetite, teeth grinding, rolling, looking at or kicking the flank, and depression. Colic can be fatal, so it must be treated promptly.
Other signs that a horse is ill can include a high temperature, flared nostrils, and poor blood flow to the gums. But any change in the condition or behavior of a horse can be a sign that the horse is not well. If you are worried about your horse’s health, always call a veterinarian immediately.
Routine veterinary care will help your horse live a long and healthy life. You should have your horse examined by a vet at least once or twice a year. One difference between medical care for horses and for other pets is that usually the horse vet will come to your animal rather than the other way around.
Horses need vaccinations against tetanus and influenza. Depending on where you live, your veterinarian may also suggest having your horse vaccinated for such diseases as rabies or West Nile virus. When needed, horses should receive medicine to expel worms (internal parasites).
Sometimes, a horse’s teeth must be floated, or filed down, to remove sharp edges. Either a vet or an equine dentist can do this.
Most horses also need shoes. All horses should have their hoofs trimmed regularly. A registered farrier can perform this job.
