Non-protein nitrogen compounds are urea (45%), free amino acids (16%), creatine (2.4%), creatinin (1.7%), ammonium nitrogen (1%), uric acid (2.1%), and other indeterminate compounds
Urea is an example of a non-protein nitrogen (NPN) source. Many NPN compounds can supply nitrogen to the rumen microbes that then build microbial protein in the rumen using this nitrogen. This microbial protein supplies the animal with protein built from the nitrogen in NPN sources.
The ability of the micro-organisms in the rumen of cattle and sheep to utilize these NPN sources to form true protein, that can be converted to meat and milk by the animals, represents an important contribution to man's food supply.
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