Question

What is meant by unwanted and rumen

Answer 1

The rumen is by far the largest compartment and is often defined to encompass everything between the oesophagus and the reticulo-rumen orifice as it is continuous with the reticulum, hence it is commonly known as the a reticulo-rumen.

Hope this is it...

Answer 2

Medical Definition of rumen. : the large first compartment of the stomach of a ruminant from which food is regurgitated for rumination and in which cellulose is broken down by the action of symbiotic microorganisms. — called also paunch. — compare abomasum, omasum, reticulum. More from Merriam-Webster on rumen.