Prospective study of equine colic incidence and mortality.

The research study focuses on exploring the incidence, morbidity, and mortality rates of equine colic in horse farms over a year-long period, detailing factors that influence the risk of colic including the age, breed, and usage of horses.

Methodology of the Research

• The researchers conducted a year-long prospective study on 31 horse farms, all of which had more than 20 horses.
• The farms were selected randomly from two neighboring counties in Virginia and Maryland.
• A total of 1,427 horses were part of the study and their data – such as their age, breed, and their usage – was collected and updated every three months.
• The study also noted the amount of time each horse spent on the farm during the research period.
• When a horse was reported to have colic by its owner, the investigators would personally visit the farm to gather additional information.

Findings Regarding Colic Incidence

• The study found that the crude incidence density rate of colic was 10.6 cases per 100 horse-years. This was calculated based on 104 reported cases over a period equating to 358,991 horse-days.
• The median farm-specific incidence density rate was 7 cases per 100 horse-years, but this varied significantly across the farms studied, ranging from 0 to 30 colic cases per 100 horse-years.
• They observed that for 81% of the reported colic episodes, a specific diagnosis was not made.
• Most of the colic episodes (67%) were treated by a veterinarian, and drugs were administered in 80% of cases.
• A major proportion of detected colic cases (75%) were classified as ‘mild’, and therefore either did not require any treatment or were resolved after a single treatment.
• Only four horses needed surgery as a result of colic.
• Just over a tenth (13%) of horses studied suffered more than one episode of colic over the course of the year.

Mortality Results

• The mortality rate from all causes was 2.5 deaths per 100 horse-years.
• Colic was responsible for a mortality rate of 0.7 deaths per 100 horse-years, and as such was the leading cause of horse death in the sample, accounting for 28% of all horse deaths.

Influence of Age, Breed, and Usage of Horses

• Horses under the age of 2 years or over the age of 10 had lower colic incidence rates than horses aged between 2 to 10 years.
• No correlation was found between a horse’s gender and its risk of contracting colic.
• In terms of breeds, Arabian horses had the lowest colic incidence rates, while Thoroughbreds experienced the highest.
• The usage of horses was also found to impact colic incidence rates. Horses used for eventing or training displayed a statistically significant higher colic incidence rate than idle mature horses.
• Conversely, horses used for lessons or horses with no specific usage had the lowest colic incidence rates.