Iowa State University animal sciences professor Colin G. Scanes has written extensively on growth hormones and endocrinology, particularly for the poultry industry. In this text designed for advanced courses in agriculture and animal sciences, he surveys the latest advances in knowledge of growth biology for the full range of domestic animals, from livestock to pets.

The origins of domesticated livestock date back at least 11,000 years to an area in what is now Iraq where sheep were first reared and pastured by neolithic humans. Since then, domestication has spread throughout the word and come to include cattle, dogs, horses, pigs and poultry. This man-animal relationship is reviewed in the early chapters before it delves into the fundamental biological process of growth and reproduction that are critical to livestock production.

"This volume covers the fundamental process of growth both from a systems viewpoint and at the organ level," Scanes explains in his Preface. "The interface of growth with other disciplines -- including nutrition, genetics, and environment/management -- are considered, as are specific aspects of growth in livestcok and companion animal species."

Scanes and other contributors to the text cover critically examine the physiological, cellular and molecular processes of production and companion animals as they grow and mature. Livestock producers, as well as dog and horse breeders, will find valuable insights in these pages. 

Genetic Selection for Lean Growth

One of the prime considerations in the meast industry is to produce -- at the least cost -- the highest quantity of muscle tissue for conversion to meat. Since growth and carcass characteristics are moderately highly heritable, it is possible to achieve improvement in carcass composition using genetic selection. 

Selection for improved growtrh rate and carcass composition will typically result in improvement in these traits. Animal scientists must be aware of changes in metabolism of muscle that are associated with improvement in growth and monitor how those changes will impact the quality of the product.