ANTIBIOTIC USAGE PRACTICES IN FOOD ANIMAL PRODUCTION

Alan G. Mathew

Department of Animal Science, The University of Tennessee, Knoxville

The use of antimicrobial products has remained an integral part of livestock production since the discovery of their benefits in the early 1950s. Estimates vary widely with regard to the relative amounts of antimicrobials used in agriculture compared to use for human therapies; however, it is most commonly reported that at least half of such products used in the US are directed towards livestock. The two primary uses of antibiotics for meat animal production include treatment or prevention of diseases (therapeutic) and enhancement of production performance (nontherapeutic). Antimicrobials, when used therapeutically are generally applied after the onset of a disease condition and are used under the direction of a veterinarian. Nontherapeutic use of antimicrobial products includes low doses (typically less than 200g/ton of feed) over longer periods of time, most often applied via inclusion in feedstuffs. The use of feed-based antimicrobial products has consistently been shown to benefit livestock production, increasing the ability of farms to maintain profitable margins, reducing effects of animal wastes on the environment, and lowering animal pathogen, and in some cases foodborne pathogen carriage in livestock. These benefits have helped in the development of modern animal production practices, allowing producers to maintain profitable margins with less labor and capital, while at the same time meeting ever increasing consumer demands for a safe, high quality, and relatively inexpensive protein source. However, concerns regarding antibiotic resistant bacteria that may disseminate from farm sources has caused a questioning of current widespread use of antimcrobial products, particularly for nontherapeutic purposes. Responses to this concern have included aggressive research efforts to identify non-antibiotic alternatives and education of producers and veterinarians regarding judicious use practices.