Prebiotics and probiotics for horses have been used as common additives to feed and supplements. Until recently, the amount of live cultures needed for colonization of the intestines was not known. Studies at the University of Toronto at Guelph highlight that the minimum amount of live cultures (measured as CFUs – colony forming units) must be at least 100 billion viable cells. For very sick horses, that requirement may go as high as 400 billion CFUs.
All mammals live in a symbiotic association with a complex population of microorganisms that inhabit their gastrointestinal tract. One of the benefits the host animal derives from this relationship is an enhanced resistance to infection and disease. Under domesticated conditions, stress factors can cause deficiencies to occur which can make the horse vulnerable to infection.