"The US livestock sector slaughters more than 150 million head of cattle, calves, hogs, and sheep and more than 55 billion pounds of poultry annually. In addition to protein for human consumption, the meat production system produces an enormous amount of byproducts that are in turn transformed into nearly 20 billion pounds of highly valuable feed and industrial products in the form of various types of fats and proteins.
Rendering is a green industry that protects the environment by recycling carbon and energy and allowing items such as byproducts to be utilized as valuable pet or livestock feed ingredients or biodiesel rather than entering a landfill. Rendering is the most efficient and environmentally sound disposal alternative and has a low carbon footprint." from the National Render's Association.