Background: Causes of chronic diarrhea range from viruses, bacteria, and intestinal parasites to inflammatory processes, including immune-mediated conditions and cancer. Diarrhea is often due to food allergy as well as poor-quality food; if this is the case, dietary changes are required. Chronic parasitic diseases, cancer and other serious conditions may also manifest as chronic diarrhea and should be investigated. Exposure to toxins in the environment may also be involved.
Symptoms: Increased volume and/or frequency of stool.
Diagnostics: Stool evaluation, blood work, complete workup of any other systems that may be involved.
Special Notes: Emotional stress can directly affect the digestive tract and should also be evaluated. If horses have been ill for an extended period, and especially after a long course of antibiotics, the balance of normal intestinal flora is likely disrupted; this can allow an influx of pathogens to become established.
Principles for Supplementation: Probiotic supplementation is important, along with support for healing of the intestinal wall. Enzymes are important in many cases, especially for horses with poor digestion.