Their digestive system is composed of the mouth, tongue, gall bladder, pancreas, the four compartment stomach (rumen, reticulum, omasum, and abomasum), salivary glands, the small intestine (duodenum, jejunum, and ileum), esophagus and the large intestine, which include. cecum, colon, and rectum (Brooker 5).
A ruminant animal uses its mouth and tongue to harvest forages and consume feedstuffs during grazing. Cattle pick up feeds during grazing by grasping and gathering the plants with their tongues and pulling them to tear for consumption. On average, cattle take from 25,000 to over 40,000 prehensile bites each day when grazing and harvest forage. Typically, spend over 30 percent of their time grazing, another 30 percent of their time chewing cud, and the rest of their time idling where they are not grazing or chewing cud (Hall 9).
The roof of their mouth is a hard dental pad without incisors. The incisors on the lower jaw work against this hard dental pad. The incisors of roughage selectors are wide and have a shovel-shaped crown while those of concentrate selectors are narrower and chisel-shaped. They have the same number of molars and premolars both on the upper and lower jaws. The ruminants use their teeth to crush and grind feeds during chewing and rumination (Hall 9).
Saliva helps in moistening the feeds hence making easy when chewing and swallowing. Saliva contains enzymes, which breaks down the starch (salivary amylase) and fat (salivary lipase) and is involved in recycling of nitrogen to the rumen. In the rumen and reticulum, the pH level is reduced by saliva. On average, in a day, a mature cow will produce up to 50 quarts of saliva. this is in relation with the amount of time they spend chewing feeds, which stimulates saliva production. The forage and feed mixes with saliva, which contains bicarbonate, sodium, phosphate, potassium and urea when consumed, to form a bolus.