Horse Hiccups-- Are They Dangerous?

A horse can get hiccups just like humans do, although it is not a very common occurrence in the animal. Hiccups are marked by sudden contractions of the diaphragm muscles in both horses and humans, although it sounds very different in horses, more like a cough than a human hiccup. The condition has been called thumps since 1831, when a British veterinarian heard the characteristic thumping noise in the horse's abdomen and labeled it as thumps.
The scientific name for thumps is synchronous diaphragmatic flutter or SDF.  When a human gets the hiccups, you might run up behind him or her and scream "boo" to scare the hiccups away, or blow up a paper bag and explode it. Doing so behind a 1,000 pound horse is definitely not a good idea and should not be attempted. Nor would it work.

Thumps is usually accompanied by twitching spasms across the horse's entire body, and many times, by a fever.  Most of the time the underlying cause is an electrolyte imbalance and fluid loss after strenuous exercise.  Low blood calcium levels could be the cause, but a thorough check of all electrolyte levels including magnesium, potassium, sodium and chlorine should be done.

Because it is most often caused by strenuous workout, it is most commonly seen in endurance horses or thoroughbred race horses after a race or workout.  In some competitions, horses exhibiting thumps will not be allowed to enter the race or other competitive activity.

Thumps can be caused by other things than a strenuous workout. Other causes of hiccups in horses are lactation, overeating, transport stress or tetany, which is a condition of very low calcium levels in the blood. Another cause is blister beetle toxicosis.

Thumps is accompanied by dehydration. If your horse develops thumps you should lead him to food and water. If your horse drinks on her own, she will probably be fine, but if she shows no interest in naturally recovering her fluid balance, she may have a fever, which is extremely serious. Then you need to call your veterinarian immediately because the dehydration could become severe and even fatal.  A vet can restore the proper levels of electrolytes. Because thumps is so rare, it is possible it will be your vet's first case!

Preventative precautions include taking extra care on hot and humid days. You may want to take the time to adjust electrolyte levels before a work out or an intense work level. You will also want to make sure your horse maintains a proper nutrition level, which is very important.  Many horse owners give their horses electrolyte supplements under advice from their vets. A good thing to do is to look for the presence of black blister beetles in bales of alfalfa, that could cause the condition. They are easy to spot as they are ½ to ¾ inches long.  Race horses should be encourage to drink water before a workout or race, even if it does add weight.