Described are strains including Enterococcus faecium strain 8G-1 (NRRL B-50173), Enterococcus faecium strain 8G-73 (NRRL B-50172), Bacillus pumilus strain 8G-134 (NRRL B-50174) and strains having all of the identifying characteristics of each of these strains. One or more of the strains can be used to treat or prevent acidosis. They can also be used to improve other measures of ruminant health and/or performance. Methods of using the strains, alone and in combination, are described. Methods of making the strains are also provided.