The
rumen, also known as a
paunch, forms the larger part of the
reticulorumen, which is the first chamber in the
alimentary canal of
ruminant animals. It serves as the primary site for microbial
fermentation of ingested feed. The smaller part of the reticulorumen is the
reticulum, which is fully continuous with the rumen, but differs from it with regard to the texture of its lining.