The Incidence of Colic

The Incidence of Colic

Most horses that experience colic do not usually reach the point where the cycle cannot be broken. Indeed, the vast majority of colic episodes resolve with no or minimal veterinary intervention.

The incidence of equine colic has been estimated by the USDA’s National Animal Health Monitoring System (NAHMS) Equine 1998 study at 4.2 events per 100 horses per year. This health monitoring system was designed to outline the overall prevalence and occurrence of various types of disease within the North American horse population.

The 1998 study found no difference in the incidence of colic among geographic regions. The percentage of equine operations that experienced one or more colic events was 16.3. Overall, only 1.4% of colic events resulted in surgical intervention.

Colic at a Glance

  • Colic means abdominal pain. It is not a specific diagnosis.
  • The intestine can twist or become trapped in areas it does not belong.
  • A number of risk factors are associated with increased incidence of colic, including a history of colic, changes in feeding programs, poor parasite control, and poor dental care.

The fatality rate for all colic events was 11%. In this same report neither gender nor use of horse was associated with the incidence of colic. There does, however, appear to be some association between some types of colic and gender. For instance, uterine torsion and scrotal herniation would be expected to be gender specific. Furthermore, colonic torsion (twisting of the large intestine) appears to be more prevalent in mares. Nonetheless, gender is not consistently a factor that affects incidence of other causes of colic.

Although gender is not a major factor in colic, the study did suggest some breeds may appear more susceptible. The NAHMS study found Thoroughbreds are more likely to develop colic (10.9 colic events per 100 horses per year) than stock horse breeds such as Quarter Horses, Paints, and Appaloosas (3.5 colic events per 100 horses per year) or other types of horses (2.9 colic events per 100 horses per year). According to several other epidemiological studies, Arabians and younger miniature horses appear to exhibit a higher incidence of colic due to fecaliths (accretions or “stones” of fecal material formed within the intestines) and small colon impactions, while Standardbreds might have a higher incidence of scrotal hernias.

The studies did not cite specific reasons for these associations. However, it is important to realize that factors other than breed might account for the heightened incidence in certain breeds. Owners of certain types of horses may be more observant of signs of colic, and various breeds may be managed and monitored differently. A genetic predisposition to certain gastrointestinal disorders could also be possible.

Age, too, may affect the incidence of colic. Age group evaluation in the NAHMS study found the following facts:

  • Foals less than six months exhibited colic at a rate of 0.2 events per 100 horses per year.
  • Horses between six and 18 months exhibited 4.5 events per 100 horses per year.
  • Horses 18 months to five years exhibited 5.9 events per 100 horses per year.
  • Horses five years to 20 years exhibited 4.2 colic events per 100 horses per year.
  • Horses older than 20 experienced 4.2 colic events per 100 horses per year.

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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