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Thesis (M.S.)—University of Nebraska—Lincoln, 1968. Department of Animal Science.


Copyright 1968, the author. Used by permission.


The ability of the ruminant to utilize various sources of non-protein nitrogen, via microbial action in the rumen, has been well established. As early as 1891 German scientists believed rumen bacteria used, by preference, amides, amino acids and ammonium salts instead of natural protein. Research has shown that much of the protein digested in the lower tract is contributed by the bodies of microorganisms which have been developed in the rumen. This appears to be the primary route of supplying protein (amino acids) to the tissue regardless of the source of nitrogen in the ration consumed.

In normal feeding programs for ruminants, the nitrogen entering the rumen will be composed of protein together with non-protein nitrogen compounds. The rumen bacteria degrade the protein, much of it into ammonia; deaminate nitrogenous bases and amino compounds; and reduce nitrate to ammonia. Under proper conditions, ammonia is utilized by the bacteria for growth together with amino acids produced by the activity of bacterial proteolytic enzymes.

The level of urea in a high energy diet that can be efficiently utilized by cattle is fairly well understood where adequate management is present and the diet is properly supplemented. The level of urea that can be effectively utilized in a high roughage ration is still demanding attention of which this report is concerned.

Data available indicates that urea is of value in supplying supplemental protein to a high silage diet for growing calves. The primary purpose of this study is to determine at what level urea could be efficiently utilized in combination with various nitrogen sources.

Advisor: Walter Woods