Muck, R.E., USDA, Agricultural Research Service, US Dairy Forage Research Center, 1925 Linden Drive, Madison, WI 53706, United States
Weinberg, Z.G., Volcani Center, Bet Dagan, Israel
Contreras-Govea, F.E., University of Wisconsin-Madison, Madison, WI, United States

Lucerne and two maize crops were ensiled with and without Lactobacillus plantarum and fermented for 4 or 60 d to assess the effect of inoculant on in vitro rumen fermentation of the resulting silages. Water and 80% ethanol extracts of the silages were also analysed for effects on in vitro rumen fermentation. The inoculant affected lucerne silage characteristics but had little effect on the maize silages. In vitro fermentation of the silages showed few effects except increased microbial biomass yield (MBY) at 24 h in the inoculant-treated lucerne silages. In vitro fermentation of the lucerne silage water extracts produced no differences due to treatment except for reduced MBY in the inoculant-treated extracts. The ethanol extracts produced results inconsistent with the in vitro results of the silages. Consequently it appears that the factor in in vitro fermentation of inoculated silages causing increased MBY was in neither the water nor ethanol extracts.