Characterization of groups N and D streptococci isolated from rumen fluids.

Twelve strains of streptococci of serological groups N and D were isolated from rumen fluids of nine cows on four rations although both groups were not isolated from the same animal. The twelve were representative of a larger number of streptococci isolated by enrichment in milk. Generally, the physiological characteristics of the isolates indicated members of the lactic or enterococcus groups; however, several were atypical in one or more of the tolerance tests. Physiologically typical Streptococcus lactis but not S. cremoris, were isolated.