There is mounting concern that use of antibiotics in livestock will contribute to antimicrobial-resistant pathogens, with repercussions for human and animal health. This report explores how limiting antibiotic use for livestock productivity-enhancement purposes may affect farmer practices and profits, as well as market prices and volumes. The animal agriculture sector is a major user of antibiotic drugs for disease treatment, disease control, disease prevention, and "production purposes" (such as growth promotion). Routine use of antibiotics-in humans or animals-can encourage antimicrobial...