The aim of this book is to give a concise account of the factors affecting the health of livestock under modern conditions of husbandry and describe the most important diseases. Most classic livestock diseases have either been completely eliminated or kept under control with vaccines or drugs but animals tend now to be affected by less obvious but nevertheless serious and often chronic infections which reduce productivity. In addition, farm animals are increasingly afflicted with metabolic disorders, which cause severely adverse effects on production and health due to partial or total collapse of the animals' metabolic processes when pushed beyond their normal capabilities. And new virus diseases, borne by wind or vectors, are causing some quite devastating effects for a time, especially in the larger livestock units. Sometimes, these diseases so cripple the enterprise that it never recovers. Much has happened since the first edition was published ten years ago. Some totally new and important diseases have emerged, and the general public has shown much greater interest in farm animal welfare. The new edition which has been extensively rewritten, reflects the new developments and challenges, and sets out in detail suitable techniques for prevention and control.