The term colic actually means abdominal pain. However, over time, it has become a broad term for a variety of conditions that cause a horse to exhibit clinical signs of pain. It is not a disease; more accurately it is defined as a clinical presentation characterized by a variety of symptoms.

It should be remembered that, as a species, horses have a very low pain threshold, and no two horses have the same level of pain sensation.
The "severity" of pain behavior, therefore, does not always predict the "severity" of the underlying cause of pain.

Signs of colic are often very different among different horses. An observant and knowledgeable owner or barn manager usually suspects the onset of colic before overt symptoms are apparent, especially if the owner/handler is familiar with the normal behavior/attitude of that particular horse. Typical examples are the horse that is lying down too much, is slightly lethargic, or is not eating as vigorously as usual. These signs in a horse without a fever could easily mean colic.

Symptoms

"Mild" Abdominal Pain

Off feed/inappetent

Pawing at the ground

Depressed/quiet

Facial expression of apprehension

Yawning

Looking toward flanks

Excessive lying down

Repeatedly lying down/standing up

Frequent attempts to urinate but not much urine is produced

Tail twitching

Abnormal stance (as if to urinate)-looks like straining to urinate

Kicks at belly occasionally

"Moderate" Abdominal Pain

Horse may be depressed or excited

The horse may make repeated attempts to go down and even roll; some horses may thrash dangerously

Not interested in feed usually

Increased respiratory effort

Spontaneous vocalization

"Severe" Abdominal Pain

Uncontrollable and dangerous rolling and thrashing on the ground

Throwing itself to the ground

Profuse sweating

Rapid and pronounced respiratory effort

May inflict self-trauma or self mutilation

Facial expression of marked apprehension

Grinding the teeth (odontoprisis/bruxism)

Ignores attempts at restraint

Some other signs of colic that are not behavioral include

Decreased defecation (may be initially increased)

Cessation of defecation

Patchy sweating

Trembling/muscle fasciculations

Treatment

For most horses affected with colic, the treatment should be preceded by a thorough examination. The veterinarian's examination should include a rectal palpation of the horse's abdomen. The thorough examination is necessary because it is important to determine whether an intestinal twist has occurred or not. If twisting is suspected, the horse must receive emergency treatment (pain relief, fluid support, and gastric decompression) and then be quickly transported to a veterinary surgical hospital.

Fortunately, most cases of colic can be readily treated by the veterinarian at the farm. Certainly, the most important treatment for colic (the behavioral effect of pain) is the administration of a pain-relieving drug, usually via intravenous injection. Veterinarians use several different drugs for this purpose.

In addition to the pain-relieving treatment, a laxative is normally given as well. The laxative is given after the veterinarian has checked the stomach for fluid distention. If the stomach is distended with fluid, it may be necessary to refer the horse to a hospital facility for treatment. In most colic cases, the stomach does not contain excess fluid and a laxative, such as mineral oil, is given.

Following control of pain and administration of a laxative, the horse may be held off feed for several hours. If the horse is allowed to consume food too soon after treatment, before the obstruction has been relieved, the additional food will simply contribute to the obstruction. It is sometimes necessary to repeat the treatments with both pain-relieving injections and laxatives before the cause of colic will resolve.

The veterinarian knows when the horse may resume feeding based on the resumption of defecation, the resolution of signs of pain, changes in the abdomen (based on palpation), and the heart rate. It is important to recognize that several hours may be needed for the obstruction to be passed. The obstruction cannot be judged to have passed before the effects of the pain-relieving medications have been allowed to wear off.

If it is not possible to control the pain associated with colic, the veterinarian may consider that referral for surgery is needed. In that event, following administration of fluids to support the circulation, the affected horse should be quickly transported to a local veterinary surgical facility.

It must be emphasized that a follow-up examination of the colicky horse is a critical component of the medical treatment. The veterinarian should re-examine the patient within a few hours of instituting treatment to ensure that the obstruction is not worsening and that twisting of the intestine is not occurring. The veterinarian will not leave the patient's side until the pain has been controlled or until the horse has been transported to a veterinary hospital facility.