A horse's digestive physiology is characterised by rapid gastric transit, rapid but intensive enzymatic digestion along the small intestine, and a protracted and strong microbial fermentation in the large intestine, as it evolved as a grazing animal It is critical to comprehend and describe feed degrading mechanisms in the horse digestive system in general, and in the hindgut ecosystem in particular. Regardless of its importance for the host's nutritional health, the cecum-colon ecosystem's significance has yet to be fully appreciated, and few investigations have focused extensively on the contribution of the hindgut microbial community to the horse's nitrogen and energy requirements. In comparison to ruminal activity, little is known about the horse's hindgut ecology. There is a scarcity of information on this microbial population's metabolism and needs. Internal bacterial markers have been frequently used to assess microbial outflow in ruminants. These approaches can be used to quantify cecum-colon microbial populations, allowing for a better understanding of this ecosystem. It's a common misconception that the optimization strategy in the hindgut is the same as in the rumen, namely, to optimise microbial growth and as a result, fermentation. We should expect the type of substrate that arrives in the hindgut under typical conditions to be nitrogen limiting, offering limited nitrogen-based substrates for microbial fermentation. We hope to compile existing information on the horse ecology and give future research views in this review study.