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© 1984, The Board of Regents of the University of Nebraska on behalf of the University of Nebraska–Lincoln Extension. All rights reserved.


This NebGuide describes the use of nonprotein nitrogen and bypass protein sources to fulfill the protein requirements of growing and finishing steers, heifers and bulls. Protein supplementation can be an expensive feed cost for cattle producers. Through the use of nonprotein nitrogen (NPN) and bypass protein sources, however, these costs can be reduced. Bypass protein is the protein that escapes breakdown in the rumen and passes "as is" into the small intestine where it is digested and absorbed. Because NPN sources are usually the most economical sources of supplemental nitrogen, NPN should be used whenever possible. The potential for using NPN depends on the ability of the rumen microorganisms to synthesize protein, the bypass protein supplied by ration ingredients, and the protein requirement of the animal.