Colic Accounts for Most Emergency Vet Calls

Colic spares few horses over a lifetime but, as horse owners know well, some episodes of colic are far worse than others. According to a recent study of veterinary emergency calls, colic that requires an after-hours veterinary visit all too frequently results in a poor outcome.^*

Researchers evaluated data from 2,600 emergency veterinary calls. Those data show that colic was by far the most common complaint precipitating emergency visits from veterinarians. In total, 35% of all after-hours emergency visits were due to colic. The next most common emergencies were wounds (20%) and lameness (11%).

Of the 2,600 emergencies, 18% (480 cases) had critical outcomes, meaning they were euthanized, died, or required hospitalization or surgery. Colic accounted for almost half of the critical cases.

This study does not reveal how many of the colic cases were sudden onset or recurrent, or whether owners had been trying to manage horses throughout the day and finally requested veterinary assistance in the evening.

“The types of colic in this study were not specifically identified, but we know that colic caused by changes in feed or feeding practices contribute to problems in both the large and small intestine,” Catherine Whitehouse, M.S., a nutrition advisor for Kentucky Equine Research, said.

Dietary factors associated with colic in horses include:

• Feeding certain types of forage that are particularly fine (e.g., coastal Bermudagrass hay) or feeding overly mature hay that can become lodged in certain sections of the gastrointestinal tract if the horse is unaccustomed to it or if water is not available.
• Limited access to forage or changes in forage source have been associated with colic episodes. “Free-choice access to pasture grazing is ideal but not suitable for all horses. Small, frequent hay meals or slow-feed tools can mimic the natural grazing behavior of horses and support digestive function,” Whitehouse advised.
• Avoid abrupt diet changes. “A general recommendation is to make any diet changes gradually over 7-14 days; however, some horses with a history of digestive issues may require an even more cautious approach to changes in diet and management,” Whitehouse advised.
• Finally, feeding one or two larger meals of concentrate rather than spreading those meals out three or four times a day to avoid large changes in fluid volume in the large and small intestine. “The horse’s body moves water in and out of the intestinal tract, particularly the large intestine, to meet the water needs elsewhere in the horse’s body. Removing water from the large intestine leaves food drier than normal, potentially contributing to an obstruction. In addition, large water fluxes alter the type of number of microbes in the large intestine responsible for fermentation,” Whitehouse explained.

Alterations in the microbiota can result in hindgut acidosis, a condition in which the pH of the cecum and colon becomes more acidic than normal. Feeds are therefore not fermented optimally, and the horse does not derive the most energy from them.

Whitehouse added, “As the hindgut becomes more acidic, fiber-degrading microbes decline and the microbiota shift towards lactate-producing microbes that can exacerbate acidosis and decrease volatile fatty acid production, which gives the horse energy.”

Research-proven supplements designed to boost gastrointestinal health in susceptible horses are available. Always choose supplements from reputable manufacturers.

^*Bowden, A., P. Boynova, M.L. Brennan, G.C.W. England, T.S. Mair, W.A. Furness, S.L. Freeman, and J.H. Burford. 2020. Retrospective case series to identify the most common conditions seen ‘out-of-hours’ by first-opinion equine veterinary practitioners. Veterinary Record:105880.