The food ingested by cows and other ruminant animals passes first within two compartments of the digestive tube called the rumen and the reticulum. Within them the food suffers the action of digestive enzymes released by microorganisms that live there in mutualist ecological interaction. In the reticulum the food is divided in some food bolus too. After passing the reticulum the food (cud) is regurgitated to the mouth to be again chewed and swallowed in a process called rumination. The digesting food then enters the omasum where it is mechanically mixed. After that the food goes to the abomasum, the organ where the chemical digestion takes place. After leaving the abomasum (the true stomach) the food bolus gains the intestine.
