Four experiments were carried out in Lelystad, The Netherlands in 1994,
in which perennial ryegrass
wilted to 421–568 g dry matter (DM) kg−1 was ensiled with
and without an inoculant containing
Lactobacillus plantarum and Enterococcus faecium strains in
1-litre capacity laboratory silos. Treated
silages showed a markedly increased rate of pH decline. The final pH of treated
silages was reached
20–30 days after ensiling, whereas acidification of control silages continued
during the full 180-day
ensilage period. After 180 days ensilage, treated silages showed significantly
(P<0·001) lower pH,
DM loss and ammonia-N concentrations and significantly (P<0·001)
higher lactic acid
concentrations than control silages in all experiments. Concentrations of
ethanol and acetic acid were
significantly (at least P<0·05) lower for the treated
silages, except for acetic acid in one experiment
and ethanol in another. Butyric acid was not found in any of the silages. One
of the control silages
(ensiled at 517 g DM kg−1) contained ethanol as the major
fermentation product indicating that
alcoholic fermentation had taken place, probably by yeasts. Treated and
untreated grasses used in the
first experiment (432 and 442 g DM kg−1, respectively) were
also used to produce silages in two 40-t
capacity clamp silos. Similar to the laboratory silos, the treated silage had
a higher lactic acid
concentration and lower pH and ethanol, acetic acid and ammonia-N concentrations
than the untreated silage.