The Season of Colic

The clinical signs associated with colic can be quite variable depending on the demeanor of the horse and how stoic he is. The usual signs that owners encounter include: pawing, rolling, kicking at the abdomen, looking at the flanks, getting up and down, sweating, depression, anorexia (lack of appetite), and phlegmon (curling the lip up). Other horses may stretch out to urinate but are unable. This may alert an owner that the horse may have difficulty urinating because of a "bean" and that his sheath may need to be cleaned.

The physical examination findings that indicate a horse is colicky include: elevated heart rate, elevated respiratory rate, decreased gastrointestinal motility, poor skin turgor (a sign of dehydration), poor mucus membrane quality (e.g. pale, injected, dry, tacky), and signs that the horse may have been struggling (e.g. abrasions over the eyes or flanks). Every colic examination that we do here at PEH includes a rectal examination and passing a nasogastric tube (NGT). On rectal examination, we may palpate impactions near the pelvic flexure or in the small colon, gas distension, displacements of the colon or other abdominal organs such as the spleen, or tight bands that may indicate a severe torsion or volvulus. Passing the NGT can be both therapeutic and diagnostic at the same time. When the NGT is passed into the stomach, reflux and gas may exit the tube. This is actually a way of relieving excess pressure on the stomach and preventing a spontaneous gastric rupture. It is also a way of administering oral fluids/electrolytes and mineral oil or other laxatives in the case of an impaction.

Other diagnostic avenues in working up a colic case include abdominocentesis ("belly tap") and abdominal ultrasound. The fluid collected from a belly tap enables us to assess the damage to the bowel. Ultrasound helps us to better define and diagnose the problem.

Colic can be divided into those cases managed medically or those requiring surgical correction. Approximately 90% of all the colics that we see in the field can be managed medically. The other 10% need hospitalization and half of those horses will eventually need surgery. The veterinarian must manage each individual colic patient and decide the best treatment plan. Parameters that help us decide to manage a patient medically versus with surgery include: abnormal findings on rectal examination (especially if tight bands are palpated), large amounts of spontaneous gastric reflux, persistent elevation in heart rate (> 60-80 bpm), uncontrollable pain, and abnormal belly tap.

Medical management of colic includes oral laxatives, oral fluids, anti-inflammatories, and generally no food for at least 24 hours or until the patient is not colicky and is passing normal manure. Intensive medical management includes IV fluid therapy, motility modifiers, and effective pain control. When the former fails to alleviate the pain, then surgery must be considered. Owners must be aware that the non-steroidal anti-inflammatory drugs (NSAID) such as bute and banamine that we have available are extremely potent and may mask a surgical colic. That is the drugs may be hiding some of the more prominent clinical signs that dictates our decision for surgery. It is a misnomer that banamine is the cure-all drug for colic.

Prevention of colic is quite difficult because we do not know exactly why horses colic. Sometimes in hindsight we are able to put the history together as to why horses colic, but a majority of the time, that is not possible. Is it a change in feed, chronic parasite problem, or disruptions in motility? I do not have a good answer for you. What preventive management tips that we can offer you are quite simple.

1. Add salt to the diet to increase water intake, one to two tablespoons twice daily for an adult 1000 pound horse.

2. Add bran mash to the diet to soften the stool.

3. Provide access to fresh water and good quality grass and/or alfalfa hay.

4. General health care including dental work and routine deworming.

5. Check the water source daily and make sure that it is not frozen.

Good luck for a colic-free season.

Leah C. Gray, DVM, dip. ACVIM