ABSTRACT
The ruminant animal occupies a unique position among mammals in that it can obtain a majority of its energy requirements from cellu lose. This is possible because of a large-scale microbial fermenta tion which takes place in the first two compartments of the ruminant stomach. Cellulolytic species of anaerobic bacteria, ciliate protozoa, and chytridiomycete fungi are all present in the rumen and can de grade cellulose to end products which serve as energy sources for the host animal. Volatile fatty acids are the principal end products produced, along with lesser amounts of lactic acid, carbon dioxide, and hydrogen. Additional products of the fermentation which can be used by the host are vitamins and microbial protein.
