The Definition of Horse Colic

Causes of Colic

• Although the causes are many and varied, it is believed that the majority of colic cases in adult horses are caused by impaction of the cecum (the area between the small and large intestines), obstruction of the large intestines, contractions of the bowel and excessive gas. Retained meconium and gastric ulcers are the principle causes of colic in foals.

Flatulent Colic

• Flatulent colic, commonly called tympanic colic, is classified as either primary tympany or secondary tympany. The primary symptom is increased gut activity due to excessive air in the colon and cecum. When tapping on the side of the horse's belly, a hollow drum-like sound will be produced. Primary tympany is indigestion caused by the fermentation of carbohydrates in the intestines by bacteria. This condition typically occurs after the horse has consumed an immense amount of grain. Grains are high in carbohydrates and an excess amount is difficult for the natural intestinal bacteria to break down. As the undigested grain passes through the small intestine into the cecum, it ferments, causing excessive amounts of gas. This gas bloats the stomach and causes severe abdominal pain to the horse. Secondary tympany is more severe due to the bowel obstructions of the colon or cecum. The excessive gas is no longer able to pass through the cecum due to the obstruction and the horse becomes acutely ill and develops toxicity.

Spasmodic Colic

• This type of colic is caused by powerful contractions of the bowel, which can be recognized by increased bowel sounds. It is believed to be the most common cause of colic. Nervous, high-strung horses appear most susceptible to spasmodic colic, which may be triggered by fright, anxiety or drinking cold water after a hot workout. Fortunately, most horses recover spontaneously in less than an hour.

Obstructive Colic

• The onset of obstructive colic is abrupt and signs are severe. Obstructive colic causes severe abdominal pain along with shock due to the release of toxins into the system. Other symptoms include depression, extremities become cool, accelerated heart rate, weak pulse and mucous membranes are muddy in color. These signs are more pronounced in cases of strangulation and unrelieved obstruction. They are due to dehydration, loss of fluids into the distended bowel, and, in some cases, to toxicity from endotoxins and degenerating gut, and peritonitis--inflammation or infection of the peritoneal or abdominal cavity.

Impaction Colic

• Impactions are mechanical blockages that occur when inadequately digested feed or foreign material forms an obstructive mass in the cecum or the large colon. Impactions tend to occur in horses that consume coarse, poor-quality feed. Horses with dental disease that are unable to chew their feed are also susceptible to impactions, as are horses that simply eat their meals too quickly. In all cases, the feed is presented to the colon in a poorly chewed, semisolid state. When the impaction is found in the small intestine, internal parasites are usually to blame.

Prevention/Solution

• A variety of management practices can be implemented to reduce the risk of colic. Horses with a history of colic frequently develop colic again. Changes in diet, the type and amount of hay fed and feeding large amounts of whole grain concentrates increase the risk of colic. Increased grazing time decreases the risk. Water must be easily accessible, clean, and, in the winter, warm enough to encourage drinking.