Since the 1950's, feeding poultry antibiotics to boost growth has been a widespread practice. But, fearing the regimen could lead to increased antibiotic-resistant infections in humans, the World Health Organization and the American Medical Association, have argued that the use of growth-promoting antibiotics should be banned.
The Johns Hopkins study did not focus on health issues but instead analyzed the cost benefits of antibiotic feeding programs.
Using data from a study of 7 million chickens previously published by Perdue Farms, a major U. S. producer, researchers found the drugs helped promote growth but cost about a penny per chicken more than the market value the bird gained from antibiotics.
The National Chicken Council, a trade group of major poultry companies, said the study was flawed because it applied average figures for costs that, in fact, vary across the country. In a statement the council also said that poultry producers use antibiotics primarily to treat disease or to promote animal health, not for growth.
The Keep Antibiotics Working coalition, which opposes the use of antibiotics in animal feed, publicized the study which appeared in the January/February edition of the journal "Public Health Reports."
Because there are no government limits or requirements for reporting, there are no precise numbers on how much of the industry uses antibiotics for growth.