Non-therapeutic use of antibiotics may result from the belief that the cost of antibiotic treatment to the producer is offset by gains in productivity, either in increased weight in food animal production or reduced costs from avoiding clinical and subclinical disease. However, a study based on Perdue company data found that productivity gains in poultry production due to the use of antibiotic growth promoters (AGPs) failed to offset the cost of antibiotics, and several other studies of commercial broilers have found no link between non-therapeutic use of antibiotics and increased productivity.11 Antibiotics did not result in higher productivity when fed to pigs during finishing, but significantly improved productivity in nursery pigs.12 Moreover, the phase-out of AGPs from swine production in Denmark did not impact long-term swine productivity.13 While economic impact may vary by the antibiotics administered, the type of animal and when in the lifecycle antibiotics are applied, studies show that response to AGPs diminish under better nutrition and hygiene practices.