The conservation of herbage as silages results in a reduction in the nutritive value of the crop as a result of extensive proteolysis. Measurement of the major end products of proteolysis such as ammonia and amino acids has been studied extensively e.g. Oshima el al. (1979). Considerably less attention has been given to the fate of plant proteins during ensilage (Fairbairn et al., 1988). Since this may lead to a better understanding of the mechanisms involved in proteolysis and thus to improvement in its control the present study was designed to follow changes in the major nitrogenous constituents, particularly proteins and peptides, through time course sampling of silages made from perennial ryegrass with and without additives.

Perennial ryegrass (23% dry matter) was ensiled in laboratory silos (1 kg fresh matter), either untreated (UT) or treated with formic acid (FA) (ADD-F, BP Chemicals, UK: 3.3 l/tonne) or a cellulase enzyme preparation (E) (FSO-1), Forum Feeds, Finland; 0.22 1/tonne).