Colic is not a disease, it is the name given to a symptom – abdominal pain.  There are a number of different types of colic:

  • Gas (or flatulent) Colic is the more common type. It occurs when there is a collection of gas in the bowel.  It causes pain as it moves through the gut by distending the bowel abnormally.  It is considered the least serious type of colic, although the violent reactions of the horse may not give that impression.
  • Obstructive Colic is when a mass of food accumulates in the bowel and prohibits passage through the intestines.  This can happen if a horse bolts his food too quickly or is given inadequate water to drink.
  • Sand Colic is prevalent in sandy areas.  It is caused by the accumulation of sand in the gut.  Horse owners in such areas should take precautions to help avoid sand colic.
  • Twisted Gut is where a portion of the intestine becomes twisted.  It is extremely serious.  Small Intestinal Strangulation Obstruction, Colonic Displacement, or Colonic Torsion are the proper medical terms for this condition.

There are a variety of things that can cause colic in horses, among them:

  • Parasites.  Both bloodworms and roundworms can cause colic – bloodworms (strongyles) by damaging the blood vessels supplying the bowel.  Roundworms can reach such a high concentration that they block the intestine.
  • Sudden changes in diet may cause colic.  Any new feed should be introduced gradually.
  • Insufficient water or unclean water.  Horses should always have access to fresh, clean water.
  • Irregular feeding.  Long intervals between meals may lead to the horse bolting his food down without chewing properly.

In gas colic, the symptoms will be intermittent, with the horse going through quiet spells followed by violent spells.  The horse may bite at his flank or roll. Even though gas colic looks violent and the horse is in a great deal of pain, the pulse usually does not rise above 50.

In obstructive colic, the consistent pain may cause the horse to paw at the ground and break into a sweat.  The pulse may rise into the 60’s.  There will be an absence of abdominal sounds, which makes it easy to a veterinarian to diagnose this type of colic.

An elevated temperature, a pulse ranging into the 80’s, and extreme pain that is non-responsive to medication often indicates vascular compromise of the bowel, requiring surgery.

Any colic should be treated seriously, as the average horse owner will not be able to tell which of the above types of colic their horse has.  The amount of apparent pain is not always a good indicator of how serious things are.  If your horse shows any signs of abdominal pain, you should call your veterinarian immediately.

While horses seem to be predisposed to colic due to their anatomy and the function of their digestive tracts, management can play a key role in colic prevention.  Although not every case is avoidable, the following guidelines from the American Association of Equine Practitioners (AAEP) can maximize the horse’s health and reduce the risk of colic:

1.   Establish a daily routine – include feeding and exercise schedules – and stick to it.

2.   Feed a high-quality diet comprised primarily of roughage.

3.   Avoid feeding excessive grain and energy-dense supplements.  (At least half the horse’s energy should be supplied through hay or forage.  A better guide is that twice as much energy should be supplied from a roughage source than from concentrates.)

4.   Divide daily concentrate rations into two or more smaller feedings rather than one large one to avoid overloading the horse’s digestive tract.  Hay is best fed free-choice.

5.   Set up a regular parasite control program with the help of your equine practitioner.

6.   Provide exercise and/or turnout on a daily basis.  Change the intensity and duration of an exercise regimen gradually.

7.   Provide fresh, clean water at all times.  (The only exception is when the horse is excessively hot; then it should be given small sips of lukewarm water until it has recovered.)

8.  Avoid putting feed on the ground, especially in sandy soils.

9.  Check hay, bedding, pasture, and environment for potentially toxic substances, such as blister beetles, noxious weeds, and other ingestible foreign matter.

10.Reduce stress.  Horses experiencing changes in environment or workloads are at high risk for intestinal dysfunction.  Pay special attention to horses when transporting them or changing their surroundings, such as at shows.

Virtually any horse is susceptible to colic.  Age, sex, and breed differences in susceptibility seem to be relatively minor.  The type of colic seen appears to relate to geographic or regional differences, probably due to environmental factors such as sandy soil or climatic stress.  Importantly, what this tells us is that, with conscientious care and management, we have the potential to reduce and control colic, which is the number one killer of horses.  Learn your horse’s vital signs and be observant of anything out of the ordinary so that you can give your veterinarian as much information as possible.

For more information about colic prevention and treatment, ask your equine veterinarian for the “Colic” brochure provided by the American Association of Equine Practitioners in partnership with Educational Partner Bayer Animal Health.  Additional colic information is available by visiting the AAEP’s horse health website,

Enteroliths are stones which form around a foreign object in the intestines of a horse, similar to a pearl’s formation.  The stones are composed primarily of struvite, which is a combination of magnesium, ammonium, and phosphate.  The struvite crystals are laid down in concentric rings around objects such as sand, pebbles, plastic, twine, hair, etc.  Smaller enteroliths are normally passed through the intestine and may be found in the horse’s droppings.  However, larger stones will result in fatal colic unless surgically removed.

The number of enterolith cases seen at UC Davis has steadily increased over the last decade.  In 1983, 18 cases were admitted to UCD with a diagnosis of enteroliths; in 1992 there were 106 cases.  So what can you do?

  • Feed preferably grass hay.  98% of horses with enteroliths had a diet of 50% to 100% alfalfa hay.
  • Reduce or eliminate bran from your horse’s diet.  Bran provides high levels of phosphorus which may contribute to enterolith formation.
  • Increase your grain to hay ratio.  This will decrease the pH level in the colon.  Horses with enteroliths had high pH levels in their colons.
  • Add one cup of vinegar a day to your horse’s diet.  This will also decrease intestinal pH levels.
  • Increase feedings to three or four times a day.  Infrequent feedings will reduce the movement of bulk feed material through the large intestine, which may provide a favorable environment for the stones to incubate and grow.
  • Provide daily exercise and avoid prolonged stall confinement which also contributes to reduced intestinal movement of feed.
  • Bed your horse on straw instead of shavings.  Straw provides an opportunity for horses to nibble on a high-fiber, bulk feed material throughout the day that is low in magnesium, phosphorous, and protein.