Risk factors for colic in the Michigan (USA) equine population.

The research study discussed risk factors for equine colic in the Michigan horse population, based on a survey of selected farms. The study found increased age, participation in shows, and events such as deworming or foaling during the survey period as risk factors. It also found that drinking water from other sources like tanks, buckets, or automatic waterers, and being a gelding reduced the colic risk.

Research Design and Participants

• The study was a prospective epidemiological study and involved a stratified sample of 3925 equines located on 138 randomly selected farms in the state of Michigan.
• The researchers followed this population for two 12-month rounds of data collection.
• Only 3175 equids from 132 farms remained at the end of the study and were used in the multivariable analysis.

Method of Analysis

• The researchers used incidence densities to describe the rate of development of colic in the study population.
• Mortality rates, case fatality rates, and survival rates were also calculated to provide insights about the severity of colic among the equines.
• They used multivariable logistic regressions (grouped according to farm) to identify risk factors associated with the occurrence of colic.

Results of the Study

• The study recorded 77 cases of colic during the period, affecting 62 animals. Out of these, 54 animals (around 87%) had one case of colic, 5 (8%) had two cases, 2 (3%) had three cases, and 1 (2%) had seven cases.
• The colic cases were also classified by type, the most common being non-specific diagnoses, followed by impaction/acute intestinal obstruction, spasmodic colic, sand colic, gas colic, verminous mesenteric arteritis, and enteritis from eating moldy grain.
• The annual incidence density of colic was found to be 3.5 cases per 100 equid-years.
• The overall mortality risk due to colic was 0.5 deaths per 100 equids, while the case fatality risk was 13%. The case fatality risk was higher for cases treated surgically (31%) than for non-surgical cases (10%).

Key Findings

• The study found that foaling during the study, deworming during the study, increased age, and participation in showing activities significantly increased the likelihood of an equine developing colic.
• Geldings and equines provided with group drinking water from sources other than tanks, buckets, and automatic waterers were found to have reduced risks of colic.