Yeasts are microscopic living organisms that are responsible for the fermentation process in the horse's hindgut. Live yeasts intended to be fed to horses should be approved under EU legislation and currently the only approved live yeast is Yea-Sacc1026 which is used in Natural Vitality Digestive Health, Digestive Health Plus, Leisure Vits & Mins, Performance Vits & Mins and the Fibremixes. The benefit of feeding live yeast to horses is that it aids fibre digestion so they can get more energy from the fibre they consume. This in return means less concentrates can be fed which will further benefit the horse's health and behaviour.