A large amount of qualitative information has been gathered on many aspects of pig biology, in areas such as genetics, growth and physiology, and welfare. This book begins with descriptions of the animal, its feed and its environment. The latest mechanistic mathematical models which describe particular physiological processes are then provided, taking into account the external factors which influence them. In conclusion, the advantages and implications of a quantitative approach to pig biology are discussed. The ideas presented will be of interest to animal scientists, particularly applied physiologists.