The Preface to the first edition of this book explained the reasons for
the publication of a comprehensive text on the rumen and rumen microbes
in 1988. The microbes of the ruminant's forestomach and those in related
organs in other animals and birds provide the means by which herbivorous
animals can digest and obtain nutriment from vegetation. In turn, humans
have relied, and still do rely, on herbivores for much of their food,
clothing and motive power. Herbivores also form the food of carnivorous
animals and birds in the wild. The importance of the rumen
microorganisms is thus apparent. But, while a knowledge of rumen
organisms is not strictly neces- sary for the normal, practical feeding
of farm animals, in recent years there has been much more emphasis on
increasing the productivity of domesti- cated animals and in rearing
farm animals on unusual feedstuffs. Here, a knowledge of the reactions
of the rumen flora, and the limits to these reactions, can be
invaluable. In addition, anaerobic rumen-type microor- ganisms are found
in the intestines of omnivores, including humans, and can be implicated
in diseases of humans and animals. They are also found in soils and
natural waters, where they playa part in causing pollution and also in
reducing it, while the same organisms confined in artificial systems are
essential for the purification of sewage and other polluting and toxic
wastes.