Storage Temperature Effects on Proteolysis in Alfalfa Silage

Abstract

ABSTRACT FIRST and third cutting alfalfa was ensiled in mini-silos (100 ml centrifuge tubes) at 40 or 55% dry matter and incubated at 15, 25 or 35 C for 40 days. In both trials and at both dry matter levels, the amount of proteolysis increased with storage temperature, averaging 10 percentage units as a fraction of total nitrogen between 15 and 35 C. Increasing storage temperature also elevated ammonia concentrations between 15 and 25 C but not between 25 and 35 C. The results of this study indicated that temperature affected the rate of loss of protease activity during fermentation, based on simulations using the silage model of Pitt et al. (1985) as modified by Muck (1987). The experiments suggest that management practices that control or reduce silage temperature may be important in maximizing the amount of nitrogen in alfalfa which remains as true protein through ensiling.