This book describes and evaluates animal biotechnology and its application in veterinary medicine and pharmaceuticals as well as improvement in animal food production. Transgenic technologies are used for improving milk production and the meat in farm animals as well as for creating models of human diseases. Transgenic animals are used for the production of proteins for human medical use. Biotechnology is applied to facilitate xenotransplantation from animals to humans. Genetic engineering is done in farm animals and nuclear transfer technology has become an important and preferred method for cloning animals. Biotechnology has potential applications in the management of several animal diseases such as foot-and-mouth disease, classical swine fever, avian flue and bovine spongiform encephalopathy. The most important biotechnology based products consist of vaccines, particularly genetically engineered or DNA vaccines. Gene therapy for diseases of pet animals is a fast developing area because many of the technologies used in clinical trials humans were developed in animals and many of the diseases of cats and dogs are similar to those in humans. RNA interference technology is now being applied for research in veterinary medicine. Molecular diagnosis is assuming an important place in veterinary practice. Polymerase chain reaction and its modifications are considered to be important. Fluorescent in situ hybridization and enzyme-linked immunosorbent assays are also widely used. Newer biochip-based technologies and biosensors are also finding their way in veterinary diagnostics. This book is an attempt to unravel the mysteries of biotechnology as it affects animal health and production.