Stimulating and thought-provoking, this important new text looks at the welfare problems and philosophical and ethical issues that are caused by changes made to an animal's telos, behaviour and physiology, both positive and negative, to make them more productive or adapted for human uses. These changes may involve selective breeding for production, appearance traits, or competitive advantage in sport, transgenic animals or the use of pharmaceuticals or hormones to enhance production or performance. Changes may impose duties to care for these animals further and more intensely, or they may make the animal more robust. The book considers a wide range of animals, including farm animals, companion animals and laboratory animals. It reviews the ethics and welfare issues of animals that have been adapted for sport, as companions, in work, as ornaments, food sources, guarding and a whole host of other human functions. This important new book sparks debate and is essential reading for all those involved in animal welfare and ethics, including veterinarians, animal scientists, animal welfare scientists and ethologists.