The cecum, large colon, small colon, and rectum make up the horse’s hindgut which contains micro-organisms (bacteria and protozoa) that break down dietary fiber found in roughage into usable components. These micro-organisms are present in the equine hind gut to digest fiber because horses lack the enzymes required to break down fiber themselves. Due to the horse’s innate hindgut micro-flora, roughage is a necessary component to a horse’s diet.
The processing of cellulose (roughage) by micro -organisms in the intestines of the horse provides the horse with energy, important vitamins and minerals, and heat. Starch (amylum) and sugars present in most ‘normal’ concentrates based on cereals is disrupting the natural horse’s intestinal flora. The good micro -organisms are taken over by other less well and sometimes even harmful organisms. So although you may think you do your horse a favor by giving him extra concentrates based on cereals, you actually disturb and undermine the proper functioning of the intestinal flora.
The best way to keep the hind gut micro-environment happy is to maximize the amount of forage being fed in the diet and to minimize the amount of grain in the diet while meeting the horse’s feed and energy requirements.