The present invention aims to provide a technique for preparing feedstuffs for ruminants with high nutritional value or feed efficiency. A process for preparing a feedstuff for ruminants of the present invention comprises: suspending a lignocellulosic material as a raw material in a liquid to give a pulp； processing the resulting pulp in a pressure type solid-liquid separator； and preparing a feedstuff containing the pulp subjected to solid-liquid separation.
