Livestock agriculture has undergone considerable changes since the end of World War II. These changes have occurred because of the use of new technologies, mechanization, increased chemical use, and government policies that favored maximizing production.

The increased use of machines and government price supports during the past century encouraged farm operators to increase the size of their farms and gain efficiencies.

As a result of these changes, food and fiber productivity in the U.S. has soared. However, because of greatly improved efficiency in production, fewer people work on farms now than 100 years ago. While almost 40 percent of the country's population lived and worked on farms at the beginning of the 20th century, today only 1.8 percent live on farms.