Routine use of antibiotics in food animals increases protein production and reduces prices.

Sir—In the policy context of assessing whether developing countries that want cheaper, more-plentiful meat would be well-advised to use animal antibiotics, Collignon and colleagues reported in a recent article that “Some persons argue that the routine addition of antibiotics to animal feed will help alleviate protein undernutrition in developing countries by increasing meat production. In contrast, we estimate that, if all routine antibiotic use in animal feed were ceased, there would be negligible effects in these countries. Poultry and pork production are unlikely to decrease by more than 2%” [1, p. 1007]. In support of these conclusions, the authors cite a US Department of Agriculture report that, they claim, “calculated that the US hog industry would have a net saving of $7 million if the use of antibiotic growth promoters ceased” [1, p. 1012]. But what the cited analysis actually says is that “Each producer is able to improve his or her net returns by feeding antimicrobial drugs. However, when all producers act in concert, feeding antimicrobial drugs, the collective result is to increase hog supplies; the increased supplies decrease hog prices” [2, p. 7]. Thus, this analysis supports the claim that feeding antimicrobial drugs to food animals (specifically hogs) expands supply and reduces prices; presumably, this is a significant finding for developing countries that desire these outcomes. Similarly, the conclusion that “Poultry and pork production are unlikely to decrease by more than 2%” [1, p. 1007] appears to be a misreading of available data that only considers weight gain among animals rather than prevention of disease and mortality (and consequent loss of production) among animals raised without antibiotics. For example, since the antibiotic growth promoter bans were imposed in Europe, “Denmark, the worldleading pork exporter, has seen the number of pigs that die from illnesses increase by 25 percent over the past decade to about seven million animals a year. Of the 32 million pigs born in the Scandinavian country last year, 21.2 percent died. ” [3, p. 1]. An increase in mortality rates from ∼17% (prior to implementation of the animal antibiotic bans) to ∼21.2% (after implementation of the bans) clearly represents a decrease in pork production of 12%. Finally, Collignon and colleagues conclude that “Eliminating the routine use of in-feed antibiotics will improve human and animal health, by reducing the development and spread of antibiotic-resistant bacteria” [1, p. 1007]. However, sound risk management policy also requires consideration of whether eliminating in-feed antibiotics will harm human and animal health by increasing the spread of antibiotic-susceptible bacteria. Recent experience in Europe suggests that this is indeed the case, and quantitative modeling suggests that the potential harm to human health from increased microbial loads of susceptible bacteria may exceed the potential benefit to human health of a decreased prevalence of resistant bacteria by a ratio of 11000:1 [4]. Thus, prudent use of animal antibiotics may be effective in helping developing countries that seek safer, cheaper, more-plentiful meat supplies to achieve these goals.