This book explains the role of hormones in improving and monitoring the production, performance, reproduction, behaviour and health of livestock animals, focusing on cattle, pigs, sheep, horses, poultry and fish. Beginning with the principles of endocrinology and the methods to study endocrine systems, it then covers the different endocrine systems that affect different aspects of animal production and describes how these systems can be manipulated or monitored to advantage. The mechanism of action is covered, and common mechanisms and themes highlighted in order to understand potential methods for altering these systems, and stimulate ideas for the development of new methods. A refreshed, updated resource that highlights new areas of endocrinology with applications in commercial animals, additions to this new edition include: - information on G protein receptors, function of CREB, methods for identification of DNA regulatory sequences and DNA binding proteins, circadian rhythm and the biological clock; - expanded coverage of in vitro models to include 3D cell culture and organ-on-a-chip; - new knowledge on gene editing, antibody production, hormone delivery methods and DNA cloning and sequencing methods; - the role of the gut microbiome, as well as effects of antibiotics and antimicrobials; - skin as an endocrine organ and related information on wool production and endocrine defleecing; - updated information on protocols for assessing endocrine disruptor chemicals. An invaluable text for students of animal science and veterinary medicine, this book also provides a useful resource for those in academia and industry interested in applications of endocrinology in animal production systems.