The first edition of this book, published in 1993, was very well received as providing a comprehensive review of the digestion and metabolism of ruminant animals. Since its publication, much new research has been conducted in the subject and knowledge has increased. This is incorporated in this second edition through the addition of five completely new chapters. These cover; the gas production technique in feed evaluation; calorimetry; the relationship between pasture characteristics and animal performance; feed processing; and the integration of data in feed evaluation systems. Other chapters have been fully expanded and updated as appropriate and Dr Dijkstra has also been enrolled as the lead editor. This book brings together quantitative approaches used in the study of mechanisms of ruminant digestion and metabolism.