Colic is a general term given for any abdominal pain. There are many types and causes of colic as well as predisposing factors. A horse’s digestive system is highly sensitive; therefore, colic is a major cause of death in horses.
There are five types of digestive colic: spasmodic, impaction, incarceration, displacement, and excessive fermentation.
Spasmodic colic is the mildest and most common. It is associated with over-excitement or sudden feed changes. It generally responds well to modest medical treatment.
Impaction colic is caused by normal ingesta or foreign material blocking the intestine. It may be caused by increased coarseness of forage, decreased intestinal fluid, or interference with normal intestinal movement. If the blockage prevents passage of gas as well as ingesta, surgical intervention may be necessary.
In incarceration colic, a loop of the intestine may become trapped within a normal or abnormal structure in the abdominal cavity. A common example is a strangulating lipoma. This situation may require surgery if the blood supply to the intestine is cut off.
In displacement colic, a portion of the intestine becomes twisted or caught in an abnormal position. The displacement may or may not be strangulating, but surgery usually is required to save the horse’s life. The picture to the right shows a nephrosplenic entrapment, where the colon (brown) becomes entrapped between the spleen (purple) and the kidney (not visual).
Excessive fermentation occurs when the stomach’s contents ferment more rapidly than they can be eliminated. This usually is caused by eating too much grain. Surgery rarely helps, and medical treatment is difficult. This situation also can cause rapid chemical changes in the blood that lead to abnormal blood flow to the hooves leading to laminitis.
There is no easy way to determine whether surgery is needed. A thorough exam and clinical judgment are required. Many times the severity of pain is the deciding factor on whether to go to surgery. Conservative treatment is utilized when possible.
A veterinarian should conduct a physical examination. The initial exam should be done from a distance to better observe the horse’s behavior. The veterinarian will check the heart rate and capillary refill time (checked on the gums) to aid in determining cardiovascular status. He or she also will listen to abdominal noises and perform rectal palpitation to check for irregularities.
Further diagnostic procedures may be required, including blood evaluation, abdomniocentesis, abdominal radiography, endoscopy, ultrasonography, and diagnosis of fecal material.
Prior to the arrival of the veterinarian: