To fully understand the changes in European animal husbandry during the long twentieth century, it is necessary to examine all aspects of the food chain devoted to supplying proteins and fats to a growing population. Indeed, the twentieth century saw great changes in animal husbandry - towards a market-oriented, intensified and specialized production. This influenced and was influenced by policies, trade, aspects of animal and public health, food supply issues, aims in animal breeding, development of production systems, principles in feeding and impact of producer cooperatives. Because it is not possible to apprehend all these global changes from a rural point of view, this book aims to bring together many different expert perspectives in fields such as: agronomy, veterinary medicine, microbiology, history of sciences, economic and cultural history, and sociology. Taking into account both national idiosyncrasies and changes from an international perspective, the book gathers scientists from Italy, Spain, France, England, The Netherlands and Sweden. The first part of the book will be devoted to the evolution of animal husbandry and commercialization from the end of the nineteenth century to the beginning of the twenty-first century. The second part of the book is devoted to the increasing medicalization of this sector with a special focus on the role of veterinarians and the on the increasing uses of antibiotics.