Common Horse Illnesses

Horse Illnesses
Horses are like every other living thing, in that sometimes they get sick. Unfortunately, as horses can’t tell us what’s wrong with them, it’s up to us to make sure we’re paying attention to them and to know how to identify some of the more common horse illnesses. Below we’ve compiled a little list of some of the more common horse diseases and ailments that can befall your beloved equine companion.

  • Azoturia– Sometimes referred to as “tying up”, equine rhabdomyolysis syndrome (ERS) occurs when a horse is fed too much without regular exercise. Symptoms include muscle cramps that make it painful for them to move. It can occur suddenly, even while the horse is being ridden or exercised. The muscles in the hindquarters will feel hot and hard to the touch. If your horse’s muscles cramp so bad that he or she cannot move, make sure you cover them with a cooler or blanket, such as the ones from Rambo to keep your horse and their muscles warm.
  • Bots– Bot flies like to land on your horse’s coat and lay several tiny, white eggs in their fur. When the horse scratches at their coat with their mouth, they ingest the eggs where they hatch into larvae that feed off the horse much like worms do. This can sometimes cause the horse pain or irritation around the mouth, and the fully developed adult flies can cause a variety of gastrointestinal problems. Aside from noticing the eggs on the horse’s coat, it’s usually not easy to tell when a horse has bots unless the problem becomes severe. There are numerous tools you can purchase for removing eggs from the fur, and dewormers work well for escalated cases.
  • Colic– Affects the digestive system of a horse. The definition of the word basically means “abdominal pain”, but in horses the stomach pain is severe and can usually be identified by a horse’s pawing, rolling, anxiety, lack of appetite, unusual gut noises (or lack thereof), or inability to pass manure. There are a few different types of colic and the severity of the condition can vary greatly, but in serious cases surgery or even euthanasia may be needed.
  • Cushing’s Disease– This illness affects the horse’s endocrine system, and sadly there is no cure for it. It is caused by a tumor on the pituitary gland, in which the gland sends out the wrong signals to the rest of the body and overproduces hormones. Symptoms of Cushing’s disease include inflammation of hoof, weight loss, mouth ulcers, excessive thirst and urination, overgrowth of coat or abnormal shedding, and changes in body shape caused by fat deposits, muscle wasting or development of pot-belly. With proper treatment, however, the horse can still live a relatively normal life.
  • Thrush– Thrush is a bacterial infection that destroys the frog tissue of a horse’s hoof. It’s caused primarily by a horse standing in wet, muddy or otherwise unsanitary conditions like a dirty stall (which is why it’s important to muck stalls at least once a day). Horses with deep clefts or narrow hoof heels are more likely to develop thrush since those areas don’t get much oxygen. Thrush is easily identifiable because you will notice an odor as well as black infected tissue when using the hoof pick on your horse. The infected areas of the hoof will easily crumble when scraped with a hoof pick. If not properly treated, the horse may become lame.
  • Tetanus– Often called Lockjaw, this disease is caused by bacteria that is often found in manure and can be picked up if your horse has a deep puncture wound or a recently healed wound, such as the naval stump on fresh foals. Signs of Tetanus include a bulging of the third eyelid, and a stiff neck that eventually progresses into the rest of the muscles. Unfortunately this disease is often fatal; however there is a yearly vaccine that prevents it.
  • Equine Encephalomyelitis– Also known as “sleeping sickness”, this illness affects the horse’s nervous system. It’s usually caused by the Equine Encephalomyelitis viruses that are carried by mosquitoes. Symptoms include depression and an elevated fever, which is then followed by a time when the horse appears to go blind, and become nervous and uncoordinated. Eventually muscle tremors set in and turn into complete paralysis. Brain lesions can also appear which cause drowsiness, ear drooping and unusual walking patterns. If contracted, death usually follows a few days after symptoms occur, but thankfully there is also a vaccine against this.
  • Strangles– This is a contagious disease that affects the respiratory systems and is caused by a bacterial infection. It can cause the glands near the throat to become enlarged and eventually burst. Signs of Strangles include a fever, depression, thick yellow discharge dripping from both nostrils and swollen abscessed lymph nodes under the jaw. If the swollen nodes get large enough, the horse may have trouble moving its head or eating (hence the name Strangles). If you suspect your horse may have this, it should be immediately isolated from others.


If you think your horse is experiencing any of the symptoms associated with these horse illnesses, do not hesitate to call your veterinarian and ask for assistance. Many of these diseases can only be confirmed with tests, and cured with special medication prescribed by your vet.


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