SELECTIVE ENUMERATION OF FUSOBACTERIUM-NECROPHORUM FROM THE BOVINE RUMEN

A culture medium containing lactate as the sole energy source and anti biotics (bacitracin, gentamicin, and streptomycin) was used for select ion and enumeration of Fusobacterium necrophorum from bovine ruminal c ontents. F. necrophorum growth was determined by indole production, an d enumeration was performed by the most-probable-number technique. The number of F. necrophorum cells in cattle fed a 100% forage diet was 7 x 10(5)/g of ruminal contents. The number increased (P < 0.05) 10-fol d after the diet was changed to 85% corn grain.