Estimate of the national incidence of and operation-level risk factors for colic among horses in the United States, spring 1998 to spring 1999.

OBJECTIVE To estimate the national incidence of, operation-level risk factors for, and annual economic impact of colic among horses in the United States during 1998 and 1999. DESIGN Epidemiologic survey. ANIMALS 21,820 horses on 1,026 horse operations in 28 states. PROCEDURES Horses were monitored for colic for 1 year, and results were recorded in a log that was collected quarterly. Operation-level data were collected via 4 on-site personal interviews. Associations between colic and independent variables adjusted for size of operation were determined. RESULTS Annual national incidence of colic in the US horse population was estimated to be 4.2 colic events/100 horses per year. Case fatality rate was 11%, and 1.4% of colic events resulted in surgery. Annual cost of colic in the United States was estimated to be $115,300,000. CONCLUSIONS AND CLINICAL RELEVANCE The national impact of equine colic is substantial because of the high case fatality rate.