Criteria for Judging a True Rumen Organism and a Description of Five Rumen Bacteria

Abstract

About 5000 isolations of bacteria from the rumina of approx. 350 cattle and sheep from several herds in 3 states have been studied. The data from these studies have been used as the basis for the following 5 criteria for true rumen bacteria: Anaerobiosis; presence in numbers of 1 million or more per g. of fresh rumen contents; isolation of a similar type bacterium at least 10 times from at least 2 animals; isolation from animals in at least 2 geographical locations; and production by the organism of end-products found in the rumen from substrates found in the rumen. A description of some physiological characteristics of 5 rumen bacteria is included.