One or more partial oxidation products of glycerol are reacted with a protein- containing fodder or fodder precursor to provide a rumen undegradable protein-containing ruminant feed product. The reaction may take place more rapidly, or at lower addition levels, or at lower temperatures than is the case when reacting spent sulfite liquor with protein-containing fodder. The partial oxidation products conveniently may be provided as a glycerose liquor containing glycerose and other side products of a glycerol oxidation reaction. The glycerose liquor may in turn conveniently be prepared by partially oxidizing biodiesel-derived glycerol.
