Effects of microbial inoculants on the fermentation, nutrient retention, and aerobic stability of barley silage

Fermentation characteristics, nutrient retention and aerobic stability of barley silages prepared using 6 commercial inoculants were evaluated using 126 mini-silos (3-L) in a completely randomized design. Whole barley forage was chopped; wilted to 39% DM and treated with water (control, S) or one of six inoculants: A (containing Lactobacillus plantarum); B (L. plantarum and Enterococcus faecium); C (L. plantarum and Pediococcus cerevisiae); D (L. plantarum, Pediococcus pentosaceus and Propionibacterium freudenreichii, plus hydrolytic enzymes); E (Lactobacillus buchneri plus hydrolytic enzymes); F (L. buchneri and P. pentosaceus plus hydrolytic enzymes). Samples of treated forage were collected for analysis at the time of ensiling, and then 18 silos of each treatment were filled. capped and weighed. Triplicate silos were weighed and opened after 1, 3, 5, 7, 33, and 61 d. On d 61, 400 +/- 5 g of material from each silo was placed in 1-L styrofoam containers, covered with cheesecloth and held at room temperature. Silage temperature was recorded hourly for 14 d via implanted thermocouple probes. Chemical composition of the forage at ensiling was consistent with previously reported values. At d 61, pH was lowest (p < 0.01) in silage S. Ammonia-N was lower (p < 0.05) in silage A than in silages S, B, E. or F. Compared to pre-ensiling values, water soluble carbohydrate concentrations were elevated in silages S, A, B. C and D, and decreased in E and F. Lactic acid concentrations were similar (p > 0.10) across treatments. Acetic acid levels were highest (p < 0.01) in silage E and lowest (p < 0.01) in silage D. Recovery of DM was lower (p < 0.01) in silage F than in silages S, A, B, C, or D. On d 61. yeasts were most numerous (p < 0.01) in silage D, which was the only silage in which temperature rose more than 2 C above ambient during aerobic exposure. Silage D also had the highest (p < 0.01) pH and ADIN content after aerobic exposure. Lactic acid and WSC content of silage D decreased dramatically during the 14-d aerobic exposure period. Yeast counts (at d 14 of exposure) were lowest (p < 0.01) in silages E and F. In general, the commercial inoculants did not appear to enhance the fermentation of barley silage to any appreciable extent in laboratory silos.