indicators of the quality of the fermentation process during ensilaging of proteinous and semi-proteinous silages. The degree of proteolysis of those crops depends on how quickly and in what way the chopped mass wilts, and also on how quickly and in what quality it is conserved. The proteins are broken apart by vegetable and bacterial enzymes (proteases) into peptides and the latter further into free amino acids. The Cornell Net Carbohydrate Protein Model has developed the need for uniform procedures to partition of feed nitrogen into A, B, and C fractions. Fraction A is non-protein nitrogen (NPN), B is true protein, and C is highly resistant to breakdown by microbial and mammalian enzymes, and it is assumed to be unavailable for the animal. During wilting of the fodder as well as in the course of its fermentation in ensilaging, there are changes of fractions of nitrogenous substances (A, B, C) that take place, under certain conditions, to disadvantage of high-quality protein fractions (B). If the silage is heated up during inadequate storage, the proportion of fraction C rises. The self-heating of the silages is caused by chemical reactions in presence of excessive oxygen (Carpinter and Suarez, 1992).