Effect of dry ice addition and wilting on the rates of fermentation and proteolysis in ensiled alfalfa.

The aim of this study was to determine the effect of dry ice addition at different levels and herbage wilting on the rate of fermentation and changes in crude protein (CP) composition in ensiled alfalfa. Alfalfa was ensiled with the addition of the following quantities of dry ice at each degree of wilting (0-h and 12-h wilting): 0 g, 0.5 g, 1 g, 2 g. Silages were made in mini silos, which were opened after 1, 3, 7, 15, 30 days. The addition of dry ice and wilting had a significant effect on the analyzed parameters (p ≤ 0.05). The slowest decrease in true protein content was noted in silage produced after a 12-h wilting with the addition of 2 g of dry ice (p = 0.014). On fermentation day 30, silage produced after a 12-h wilting with the addition of 2 g of dry ice was characterized by the significantly lowest proportions of fractions of ammonia nitrogen (PA1) (p = 0.027), buffer-soluble true protein (PA2) (p = 0.028), and indigestible protein (PC) (p = 0.044), and the highest proportions of fractions of buffer-insoluble true protein (PB1) (p = 0.045) and fiber-bound protein (PB2) (p ≤ 0.001). The study demonstrated that the addition of 2 g of dry ice combined with a 12-h wilting prior to ensiling positively influenced the fermentation pattern and reduced proteolysis, thus improving the nutritional value of CP in alfalfa silage.