When a Horse Colics: The Physical Examination

When a Horse Colics: The Physical Examination

A rectal thermometer is a necessary tool for monitoring your horse's temperature in case of infection.

Photo: Anne M. Eberhardt/The Horse

A general physical examination is performed as part of the clinical evaluation of the horse exhibiting colic.

This examination is termed “general” because it focuses on examination parameters that are not specific for conditions most often associated with a colic episode. However, these parameters are important in evaluating the overall current health status of the horse (i.e., how stable the animal is at the time of the examination). The parameters most likely to be evaluated include a rectal temperature, heart rate, respiratory rate, capillary refill time, and an evaluation of the mucous membrane color.

The rectal temperature must be taken before performing any rectal examination because air introduced into the rectum will falsely lower the temperature. The normal rectal temperature should usually be below 101 degrees Fahrenheit. Normal rectal temperatures of foals tend to be slightly higher but should generally be below 102 degrees Fahrenheit. Increases in body temperature may occur in a normal animal after activity, excitement, or anxiety. However, body temperatures greater than 103 degrees often suggest an inflammatory and/or infectious condition that may be directly associated with or be the cause of colic.

Colic conditions commonly associated with fevers include anterior enteritis, peritonitis, colitis, and intestinal rupture. Low body temperatures are often seen with severe circulatory disturbance and shock.

The heart rate, respiratory rate, mucous membrane color and moisture, and capillary refill time help the veterinarian determine such things as the degree of pain (by heart rate and respiratory rate) and compromise of general body blood flow and distribution (by heart rate, mucous membrane color, and capillary refill time).

A horse with severe disturbance of blood flow due to dehydration, loss of fluid into the intestinal tract, uneven and poorly coordinated blood distribution, and endotoxemia would be expected to exhibit a high heart rate and dark red to purple dry mucous membranes with a slow capillary refill time (three seconds or more).

Such a horse may also exhibit a high respiratory rate due to body acid/base disturbance and/or pain. Other parameters of hydration may be evaluated, but their interpretation can be highly subjective if the state of dehydration is not severe.

Findings that may further indicate dehydration include prolonged skin tenting after being pinched on the shoulder or neck, slow jugular vein filling after holding it off at the base of the neck, sunken eyes, depression, and high heart rate. A high heart rate is also indicative of abdominal pain but can also be due to several other factors, including dehydration and endotoxemia. The relative significance of all factors that may affect the heart rate must be interpreted in light of the other clinical findings.

After, or along with, the initial evaluation, the veterinarian usually listens to the abdomen (auscults) for evidence of rumbling sounds that indicate intestinal movement (termed borborygmi). This evaluation is subjective. The examining veterinarian notes whether there is lack of intestinal sounds. If sounds are present, then the veterinarian notes the frequency of intestinal sounds as an indication of intestinal motility, their intensity, and location.

Although this examination may help ascertain an overall impression of intestinal motility, it is not very specific. On occasion, an experienced veterinarian might hear the sound of sand moving in the intestines. These “sand sounds” are subjectively assessed and more likely to be heard in horses that live in areas with large amounts of sand in the soil. Otherwise, much of the information from abdominal auscultation serves only to answer very general questions regarding intestinal motility. These questions may include the following:

  1. Is there any motility?
  2. Does the motility sound organized?
  3. Is the motility uniform throughout the abdomen?
  4. Is the motility decreasing or increasing in intensity,duration, and frequency?
  5. Are there any sounds that may indicate a large gas viscus (an intestinal accumulation of gas)?

This last question is often addressed by simple auscultation and by abdominal percussion using a finger-flicking motion to the abdominal wall. A gas-distended viscus produces a “ping” sound, similar to the sound of a playground ball that “pings” as it hits the pavement.

About the Author

Bradford G. Bentz, VMD, MS, Dipl. ACVIM, ABVP (equine)

Brad Bentz, VMD, Dipl. ACVIM, ABVP, ACVECC, owns Bluegrass Equine Performance and Internal Medicine in Lexington, Ky., where he specializes in advanced internal medicine and critical care focused on helping equine patients recuperate at home. He’s authored numerous books, articles, and papers about horse health and currently serves as commission veterinarian for the Kentucky State Racing Commission.

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