In a ruminant feed, rumen undegraded protein (“RUP”), which is protein orally ingested and passed through the rumen in an undegraded or undigested state, is determined through analysis of feed components in the feed and is used to modify the feed formulation to control a level of RUP exiting the rumen of the ruminant. Additionally the RUP and rumen undegraded neutral detergent fiber (“RUNDF”) content of selected feed components may be received based on an analysis of the feed components and the feed ration may be formulated accordingly. The RUP content may be determined by comparing analysis results with a calibration curve of previously analyzed feed components.
