Photo: Anne M. Eberhardt/The Horse

Do you give your foals probiotics to prevent diarrhea? New research suggests that perhaps you shouldn’t. It appears that the substance meant to put a halt to diarrhea isn’t stopping it and, in fact, might even encourage it.

Designed to enhance the body’s defense, probiotics can produce antimicrobial compounds that target intestinal pathogens and their toxins. In theory, and even in in vitro (laboratory dish) tests, the concept seems to work. However, results from a new study by scientists in Switzerland suggest that in the living foal, the probiotic’s effects are disappointing.

“Our results are a bit frightening, particularly because probiotics are often given under the assumption that ‘even if they don’t work, they won’t cause any harm,’” said Angelika Schoster, DrMedVet, DVSc, PhD, Dipl. ACVIM, ECEIM, senior clinical lecturer at the University of Zurich’s Vetsuisse Faculty in the Clinic for Equine Internal Medicine, in Zurich