Antibiotic use in livestock is the use of antibiotics for any purpose in the husbandry of livestock, which includes treatment when ill (therapeutic), treatment of a batch of animals when at least one is diagnosed as ill (metaphylaxis - similar to the way bacterial meningitis is treated in children), preventative treatment against disease or prophylaxis of infection, but also the use of subtherapeutic doses in animal feed and/or water to promote growth and improve feed efficiency in intensive animal farming outside of Europe, where the last practice has been banned since 2006. This article primarily looks at antibiotic use for growth promotion and the situation in the United States.