<P> Like all ruminants , sheep have a complex digestive system composed of four chambers , allowing them to break down cellulose from stems , leaves , and seed hulls into simpler carbohydrates . When sheep graze , vegetation is chewed into a mass called a bolus , which is then passed into the rumen , via the reticulum . The rumen is a 19 - to 38 - liter ( 5 to 10 gal ) organ in which feed is fermented . The fermenting organisms include bacteria , fungi , and protozoa . ( Other important rumen organisms include some archaea , which produce methane from carbon dioxide . ) The bolus is periodically regurgitated back to the mouth as cud for additional chewing and salivation . After fermentation in the rumen , feed passes into the reticulum and the omasum ; special feeds such as grains may bypass the rumen altogether . After the first three chambers , food moves into the abomasum for final digestion before processing by the intestines . The abomasum is the only one of the four chambers analogous to the human stomach , and is sometimes called the `` true stomach '' . </P>
<P> Like all ruminants , sheep have a complex digestive system composed of four chambers , allowing them to break down cellulose from stems , leaves , and seed hulls into simpler carbohydrates . When sheep graze , vegetation is chewed into a mass called a bolus , which is then passed into the rumen , via the reticulum . The rumen is a 19 - to 38 - liter ( 5 to 10 gal ) organ in which feed is fermented . The fermenting organisms include bacteria , fungi , and protozoa . ( Other important rumen organisms include some archaea , which produce methane from carbon dioxide . ) The bolus is periodically regurgitated back to the mouth as cud for additional chewing and salivation . After fermentation in the rumen , feed passes into the reticulum and the omasum ; special feeds such as grains may bypass the rumen altogether . After the first three chambers , food moves into the abomasum for final digestion before processing by the intestines . The abomasum is the only one of the four chambers analogous to the human stomach , and is sometimes called the `` true stomach '' . </P>
the digestive system of a sheep has evolved to
the digestive system of a sheep has evolved to
break down cellulose from stems , leaves , and seed hulls into simpler carbohydrates
break down cellulose from stems , leaves , and seed hulls into simpler carbohydrates