synthetic hormones, including estrogen and testosterone, produce leaner, more muscular cattle more rapidly and on less feed There is ongoing research into a variety of growth factors and other drugs that would help producers fine-tune the growth and proportions of fat to lean in cattle and other meat animals Currently, beef producers are allowed to treat meat cattle with six hormones in the United States, Canada, Australia, and New Zealand, but not in Europe Hormone treatments were outlawed in the European Economic Community in 1989 in response to well-publicized abuses; a few Italian veal producers injected their calves with large quantities of the banned steroid DES, which ended up in bottled baby food and caused changes in the sexual organs of some infants Laboratory studies indicate that meat from animals treated with allowed hormone levels contains only minute hormone residues, and that these residues are harmless when ingested by humans Antibiotics Efficient industrial-scale meat production requires that large numbers of animals be raised in close confinement, a situation that favors the rapid spread of disease In order to control animal pathogens, many producers routinely add antibiotics to their feed This practice turns out to have the additional advantage of increasing growth rate and feed efficiency Antibiotic residues in meat are minute and apparently insignificant However, there’s good evidence that the use of antibiotics in livestock has encouraged the evolution of antibiotic-resistant campylobacter and salmonella bacteria, and that these bacteria have caused illness in U.S consumers Because resistant bacteria are more difficult ... advantage of increasing growth rate and feed efficiency Antibiotic residues in meat are minute and apparently insignificant However, there’s good evidence that the use of antibiotics in livestock has encouraged the evolution of. .. favors the rapid spread of disease In order to control animal pathogens, many producers routinely add antibiotics to their feed This practice turns out to have the additional advantage of increasing growth rate and feed...that these residues are harmless when ingested by humans Antibiotics Efficient industrial-scale meat production requires that large numbers of animals be raised in close confinement, a situation that