This text explains the role of hormones in improving and monitoring the production, performance, reproduction, behavior and health of livestock animals. It covers different endocrine systems and how these can be manipulated to advantage, covering the mechanism of action and highlighting common themes to help stimulate 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.