Some horses develop semiformed feces when first introduced to lush pastures, alfalfa hay, or a temporarily stressful situation (eg, trailer ride, racing, showing, visit to a veterinary hospital). This change in fecal consistency is not of medical significance as long as the horse is healthy in all other regards, but owners may be concerned. It is important that horses with diarrhea have a physical examination and appropriate laboratory tests to exclude infectious causes and to determine whether treatment is required. Usually, the fecal consistency returns to normal when the horse adapts to its new diet or the stressful situation resolves.
Last full review/revision September 2013 by Allison J. Stewart, BVSC (Hons), MS, DACVIM-LA, DACVECC