Cellulose digestion by rumen microorganisms as influenced by cereal grains and protein-rich feeds commonly fed to cattle using an artificial rumen.

N UMEROUS communications from this laboratory, Burroughs et al. (I949a, I949b, I949c, I95oa, I9~ob, and I9~oc) have called attention to the influence of nutrients needed by rumen microorganisms in the digestion of roughages, particularly the cellulose fraction. Hungate (I9~o), after extensively reviewing the literature pertaining to rumen cellulose digesting bacteria, concluded that: "Further improvements (cellulose digestion) based on exact studies of the nutritional requirements of the tureen microorganisms appear highly desirable. In approaching the problem it should be kept in mind that the first step in ruminant nutrition is microbial nutrition." The feeding of cattle and other ruminant animals often includes the feeding of grains and protein-rich feeds in combination with roughage. The possibility was presented that these grain and protein-rich feeds when fed with roughage might supply nutritional factors needed by rumen microorganisms in the digestion of the roughage fraction of the ration. The purpose 'of this paper is to present evidence that certain grain and protein-rich feeds contribute to the nutrition of cellulose.digesting tureen microorganisms. Experimental Methods