How does antibiotic use in animals differ from use in humans?
In humans, antibiotics are usually used to treat sick individuals but can occasionally be used to prevent illness. Sick animals are sometimes treated individually, but often whole flocks or herds of animals are treated at once, including animals that are not ill. In humans, antibiotics are sometimes given to healthy persons to prevent specific infections; this type of use is much more common in animals. In humans, antibiotics are not given to promote growth, yet this is a major reason for using antibiotics in animals. How much is used in food-producing animals? In the United States, data on the quantity of antibiotics given to food animals is not available to the public or to government agencies. According to the Union of Concerned Scientists (www.ucsusa.org), about 25 million pounds of antibiotics and related drugs are used every year in livestock for nontherapeutic purposes. The Animal Health Institute (www.ahi.org) estimates that 20.2 million pounds of antibiotics were produced for
