The cattles, buffaloes, goats, sheep, deer and camels are herbivorous animals that feed on plant leaves, twigs, etc. Their stomach consists of 4 chambers: rumen (paunch), reticulum (honeycomb), omasum (psalterium) and abomasum (rennet). In the rumen, food undergoes mechanical and chemical breakdown. Mechanical breakdown results from thorough churning brought about by muscular contractions and aided by cornified surface of villi. Chemical breakdown is caused by symbiotic micro-organisms bacteria such as Ruminococcus and ciliate such as Entodinium caudatum. These micoorganisms live as symbionts in the rumen and reticulum of the stomach of the ruminants (e.g., cows and buffaloes) and in the large intestine of other herbivorous mammals (e.g., horses and donkeys) and release enzymes, cellulases, which act on cellulose and simplify it to shortchain fatty acids. Cellulose is not digested in human being.