Apparatus and process for separating feed for livestock along a cutting face. The apparatus is provided with a cutting unit (9, 72) comprising at least one knife (32, 33, 74), such as a band knife (74) or a rotary knife (32, 33). The knife (32, 33, 74) has cutting teeth (58, 77) having at least two cutting edges (59, 78, 79). A drive (28, 29) drives the knife (32, 33, 74) in a continuous cutting motion in a reversible cutting direction which is parallel to the cutting plane.