This volume is comprised of invited papers presented at the Seventh International Symposium on Ruminant Physiology, held in Sendai, Japan, in September 1989. Papers are invited on the recommendations of 300 international experts. The proceedings of this symposia provides the most comprehensive coverage available of current research in ruminant physiology.

The International Symposium on Ruminant Physiology (ISRP) is the premier forum for presentation and discussion of advances in knowledge of the physiology of ruminant animals. This book brings together edited versions of the keynote review papers presented at the symposium.

Fundamental research on sheep and cows has often provided answers to significant questions, not only for investigators of the gastrointestinal tract of ruminant and other species, but also for workers in practical areas such as world food supplies, animal husbandry, and medical practice. This book is an interdisciplinary survey of some of the most recent advances in ruminant research, especially on comparative aspects of the digestive tract. Fourteen articles by an international group of leading scientists cover a wide range of topics: comparative anatomy related to digestive function; microbial ecology; pathophysiology; neurophysiology; endocrinology; ionic transport; energy, intermediary, and mineral metabolism; and differential rate of flow of digesta.

Lipid Metabolism in Ruminant Animals is a nine-chapter book that first discusses the anatomy, physiology, and microbiology of the ruminant digestive tract. Subsequent chapters center on lipid metabolism in the rumen; digestion, absorption and transport of lipids in ruminant animals; the composition, structure and function of lipids in the tissues of ruminant animals; and the effects of diet and other factors on the lipid composition of ruminant tissues and milk. Other chapters focus on lipid metabolism in the mammary gland, adipose tissue, liver, and other selected tissues of ruminant animals.

Two questions could not be avoided in the avant-propos of this book; (i) what is the importance to man of ruminant livestock, and (ii) what results of practical relevance in the growing mountain of scientific verbiage could be found in the Proceedings of this Symposium. Herbivores are an integral and critical part of the natural ecosystem which must be preserved because of their impact on human welfare. Wh at makes ruminants especially important to man is that they can thrive on fibrous forage and are thus the only viable enterprise over much of the earth's surface where crop growing is impracti cable. They contribute a wide array of products in addition to 50000 000 tonnes ofmeat (1977) and represent a 'capital reserve' that can be drawn upon in times of emergency: milk for example (450000000 tonnes) can make the difference between subsistence and starvation. About 60% of the world's meat and 80 % of the milk are produced by one third of the world ruminant population in the developed regions and as much as 99 % of the power for agriculture is provided by the ruminant population in developing countries. For the next two decades, a probable increase by 30 % for . cattle and buffalo and more than 40 % for sheep and goats is expected by improving health, fertility, nutrition and genetic potential rather than feed resources.

This monumental text-reference places in clear persepctive the importance of nutritional assessments to the ecology and biology of ruminants and other nonruminant herbivorous mammals. Now extensively revised and significantly expanded, it reflects the changes and growth in ruminant nutrition and related ecology since 1982. Among the subjects Peter J. Van Soest covers are nutritional constraints, mineral nutrition, rumen fermentation, microbial ecology, utilization of fibrous carbohydrates, application of ruminant precepts to fermentive digestion in nonruminants, as well as taxonomy, evolution, nonruminant competitors, gastrointestinal anatomies, feeding behavior, and problems fo animal size. He also discusses methods of evaluation, nutritive value, physical struture and chemical composition of feeds, forages, and broses, the effects of lignification, and ecology of plant self-protection, in addition to metabolism of energy, protein, lipids, control of feed intake, mathematical models of animal function, digestive flow, and net energy. Van Soest has introduced a number of changes in this edition, including new illustrations and tables. He places nutritional studies in historical context to show not only the effectiveness of nutritional approaches but also why nutrition is of fundamental importance to issues of world conservation. He has extended precepts of ruminant nutritional ecology to such distant adaptations as the giant panda and streamlined conceptual issues in a clearer logical progression, with emphasis on mechanistic causal interrelationships. Peter J. Van Soest is Professor of Animal Nutrition in the Department of Animal Science and the Division of Nutritional Sciences at the New York State College of Agriculture and Life Sciences, Cornell University.