EFFECTS OF SILAGE INOCULANTS ON SILAGE FERMENTATION, AEROBIC STABILITY AND ANIMAL PERFORMANCE

Abstract

Ferulic acid constitutes a major constraint to ruminal fibre digestibility. The overall objective of this study was therefore to determine the effects of a first (non-fibrolytic) - or a third (ferulic acid esterase-producing) - generation inoculant on the fermentation characteristics, aerobic stability and nutritional value of silages. In experiment 1, barley and corn silages were inoculated with a first-generation inoculant containing Lactobacillus plantarum, Enterococcus faecium and Pediococcus acidilactici in a 2 × 2 factorial design. Inoculation induced a more homolactic fermentation in barley than in corn silage but did not improve aerobic stability, DM intake, in situ digestibility or growth performance of growing feedlot steers. Aerobic stability of barley silage, and DM intake and growth performance of steers fed barley silage were improved as compared to corn silage. In experiments 2 and 3, barley silage was inoculated with a third generation inoculant containing ferulic acid esterase-producing Lactobacillus buchneri in combination with Lactobacillus plantarum and Lactobacillus casei. The inoculated silages had higher concentrations of acetic acid and were more aerobically stable than uninoculated silage. Inoculation increased in situ fibre digestibility (experiment 2) and feed efficiency for growing feedlot steers (experiment 3). In the final experiment (experiment 4), barley silage was chopped to a theoretical chop length (TLC) of approximately 1.0 (SC) or 2.0 cm (LC) and inoculated without or with the same inoculant used in experiments 2 and 3 in a 2 × 2 factorial design. Inoculation increased the concentration of acetic acid in the LC silage and improved its aerobic stability, but decreased the concentration of acetic acid and had no effect on the aerobic stability SC silage. Growth performance of finishing feedlot steers were neither affected by TLC, inoculation nor their interactions, however, the proportion of saleable meat and rib eye area of steers was greater for SC than for LC. In conclusion, this study demonstrated that third-generation inoculants could be used to improve the nutritional value of barley silage. Third-generation inoculants could also allow TLC to be increased from 1 to 2 cm without adverse effects on silage fermentation or quality.