Effects of a multi-strain inoculant on the fermentation characteristics of lucerne silage.

An effective biological additive contains a range of specifically selected strains of bacteria designed to dominate and direct the fermentation of silage. The multi-strain inoculant (Microsil Extra Plus (MEP), Medipharm, Sweden) was tested for its ability to reduce pH, and improve the fermentation profile and aerobic stability of lucerne (Medicago sativa) silage. Lucerne at 340 g kg-1 dry matter (DM) from five fields was untreated or treated with MEP at 1.5×105 colony forming units g-1 fresh forage before ensiling in 0.7 and 3-litre silos. Treatments were replicated three times. Addition of MEP resulted in a more rapid reduction of pH after 3 days (4.79 vs. 5.28; P<0.01) and 97 days of ensiling (4.53 vs. 4.97; P<0.01). Silage prepared with MEP had a higher concentration of lactic acid (26 vs. 20 g kg-1 DM; P<0.01) and a lower concentration of butyric acid (1.0 vs. 5.1 g kg-1 DM; P<0.05) and ammonia-N (41 vs. 63 g kg-1 total N; P<0.01). The MEP also reduced fermentation losses (61 vs. 85 g kg-1 DM). While MEP silage had a marginally better aerobic stability, both treated and untreated silage were aerobically stable for more than six days.