Intake, digestibility and aerobic stability of barley silage inoculated with mixtures of Lactobacillus plantarum and Enterococcus faecium

Abstract

The effect of ensiling barley treated with two bacterial inoculants containing mixtures of Lactobacillus plantarum and Enterococcus faecium (1.0 × 10 5 cfu g −1 as fed silage) on the nutritional value and aerobic stability of barley silage was examined. Inoculants differed in the strains they contained and were originally selected by Pioneer Hi-Bred International for use with corn or alfalfa silage, SILA-BAC ® (1174), or with grass silage (X2637). Concentrations of water-soluble carbohydrates were higher (P < 0.05) in inoculated than in control silages. Although inoculants appeared to increase the numbers of lactic acid producing bacteria (LAB) at ensiling, post-ensiling numbers (cfu g −1 ) of yeasts and molds were lower (P < 0.05) in inoculated than in control silages. Lactic acid concentrations and pH were similar among the silages and variations m the growth of yeast and mold populations could not be explained by differences in the production of volatile fatty acids (VFA) among silages. Inoculation of barley silage with either inoculant increased (P < 0.01) the average daily gain of lambs. A digestibility experiment with 12 growing ram lambs showed that inoculants did not alter (P > 0.05) DM intake, feed efficiency or the digestion of DM, organic matter, acid detergent fiber (ADF) and neutral detergent fiber (NDF). Nitrogen intake and retention were greater (P < 0.05) in lambs fed silage inoculated with 1174 as compared with control silage. Yeast populations were increased (P < 0.05) in control and 1174 after 2 d of exposure to air but it required 13 d for a similar yeast population to be established in X2637 silage. Increases in the mold populations within the silages were noted after 2, 5 and 13 d of exposure to air for control, 1174 and X2637, respectively. The temperature of control silage increased (P < 0.05) 2 d after exposure to air, whereas increases in temperature were delayed for 4 d in 1174 and 8 d in X2637. Temperatures rose as high as 30 °C in control silage, but did not exceed 24 °C in inoculated silages during the 13 d period. Key words: Barley silage, inoculant, digestion, aerobic stability, sheep, gain