Why and how antibiotics are used in swine production.

In summary, published research data clearly show that the use of antibiotics during all phases of growth benefits the rate and efficiency of body weight gain, reduces mortality and morbidity, reduces subclinical disease, and improves health in pigs. Also, antibiotics at breeding and during lactation benefits reproductive and lactational performance in sows. The economic benefits are several-fold greater than the cost of the antibiotic when a cost-effective antibiotic is used for this purpose. Monitoring and surveillance of microbial resistance in animals and humans has continued, with no animal-to-human infection path being clearly delineated. Although the incidence of antibiotic resistance in the human population remains high, there is no clear evidence that the levels or patterns have changed. The high levels of antimicrobial resistance in humans likely result from antibiotics prescribed directly to humans, because well over half of the antibiotics produced in the United States is used in human medicine. Whether antibiotic usage in swine, poultry, and other food-producing animals contributes to antibiotic resistance in the human population will continue to be debated. Even though antibiotics have been fed for nearly 50 years to literally billions of animals, there is still no convincing evidence of unfavorable health effects in humans that can be directly linked to the feeding of subtherapeutic levels of antibiotics to swine or other animals. Hopefully, policy decisions in the future regarding the use of antimicrobials in animals will be based on science and sound risk assessment, and not on emotionalism.