or meat-processing, wholesale business of buying and slaughtering animals and then processing and distributing their carcasses to retailers. The livestock industry is among the largest in the world. In the United States, the plains of the Midwest and Southwest provided good conditions for inexpensively breeding livestock, which was then transported to centrally located packing centers, such as Chicago and Cincinnati, and marketed in the densely populated eastern states. Chicago's Union Stock Yards (1865) was the nation's largest livestock and packing center until the mid-20th cent. It was closed in 1971, because it was unable to compete with newer, more modern facilities. Modern meatpacking dates from the introduction of refrigerated railway cars. In 1869, George Hammond, a meatpacker in Detroit, shipped frozen beef to Boston in a car chilled with ice from the Great Lakes. By 1880 mechanical refrigeration was being used. The introduction of storage and distribution warehouses made possible the rapid and efficient marketing of meat. The grain belt and the high plains of the Midwest are still distribution centers for livestock products in the United States.
Meatpacking byproducts include hides for leather; edible fats; inedible fats for soap; bones for buttons; blood meal for fertilizer; hair for brushes; intestines for sausage casing; as well as gelatin, glue, and glycerin. Byproduct pharmaceuticals include pepsin, testosterone, liver extract, thyroxine, epinephrine, albumin, insulin, thromboplastin, bilirubin, and ACTH.
Federal legislation requires humane slaughtering methods and examination for disease for livestock killed for export or interstate trade. The Wholesome Meat Act of 1967 extended inspections to intrastate trade. A new inspection system requiring scientific tests for bacteria was put in place in 1996. The laws are administered by the U.S. Dept. of Agriculture (USDA). The USDA's grading service stamps beef prime, choice, select, standard, commercial, utility, cutter, and canner, according to the amount of its fat. See also beef; mutton; sausage.