Epiphytic LAB, e.g., lactobacilli, lactococci, enterococci, pediococci, streptococci, and leuconostocs, play a major role in silage fermentation. Their numbers and populations have become a concern in predicting the adequacy of silage fermentation and in determining whether or not to apply a bacterial inoculant (Bolsen et al, 1989). Epiphytic LAB counts are usually low and variable on silage crops (Lin et al, 1991), and increases in the LAB counts usually occur coincident to the chopping process. Only limited information is available concerning the succession of epiphytic LAB species during the ensiling period of alfalfa (Medicago sativaL.) and maize (Zea mays L.), the two major silage crops in North America. The present studies investigated the epiphytic LAB succession during the pre-ensiling and ensiling periods for two cuttings of alfalfa, each harvested at three stages of maturity, and three whole-plant maize hybrids.

A second-year stand of alfalfa was harvested at the 2nd and 4th cuttings and at the late-bud, 10% bloom, and 50% bloom stages of maturity within each cutting in 1989. Following mowing, the alfalfa was wilted in the windrow for 5 to 6 hours prior to precision chopping.