The hindgut of the horse has a microbial population that includes bacteria, fungi, protozoa and yeasts. These are present in the large colon and caecum in order to ferment and breakdown the fibre portion of the diet, which is resistant to enzymatic digestion in the small intestine. The fermentation of fibre in the hind gut produces volatile fatty acids (VFA’s) which the horse utilises for energy and also synthesises B vitamins which are essential to many physiological processes. Modern diets of performance horses often feature reduced fibre intakes and helpful aids to the microbial population in the hindgut can be useful. These additions are called prebiotics and MOS and FOS (Mannan-/fructo-oligosaccharides) are examples of these. MOS works as a pathogen binder and helps prevent undesirable bacterial species from colonizing the hindgut while FOS works hard to promote the growth of beneficial bacteria. Connolly’s Red Mills Horse Care range, including the Grocare and Performacare balancers, all contain MOS and FOS to help promote hindgut digestion in the performance horse.