Crude Protein is a measure of the protein content of food calculated from its Nitrogen content. It is normally expressed either as a percentage or in g/kg of Dry Matter in the food (g/kg DM). For example, a feed label may read 17% CP or 170g/kg. Because CP is calculated from the chemical analysis of all the Nitrogen present in a food, including non-protein Nitrogen like Urea, it may overestimate the true protein content. Non protein Nitrogen, particularly in the form of Urea can be utilised by ruminant herbivores like cows and sheep to make protein, but not by horses which have a low tolerance for Urea.
