Evidence is mounting that the routine use of antibiotics to promote growth in farm animals is unnecessary and can pose a threat to humans. At the same time, momentum is building to change farming practices to grow healthy cows, pigs and poultry without using drugs. So far the biggest prod for change came from McDonald’s, one of the world’s largest buyers of meat. The restaurant chain in June announced that it was asking its suppliers to stop using antibiotics to promote growth. Another big push came when Sens. Olympia Snowe and Edward Kennedy introduced a bill to limit the use of drugs in livestock to promote growth rather than fight illness.

These efforts got a boost recently when the World Health Organization released a report showing that the pork and poultry industries can thrive without relying on antibiotics to enhance animal growth. The conclusion was based on the experience of Denmark where non-therapeutic antibiotic use was stopped completely by 1999. Sine then, the WHO found, there has been a 54 percent reduction in the use of such drugs leading to a large decrease in the levels of antibiotic-resistant bacteria found in farm animals. This means a smaller threat to public health, although the report acknowledged that instances of human health problems caused by resistance to drugs fed to animals were rare in Denmark before the ban because the country has high standards for hygiene and closely monitors antibiotic use and patterns of drug resistance.

The WHO report reiterates that reducing the routine feeding of drugs to healthy animals is a good idea. Farms now use antibiotics to make up for overcrowded and dirty conditions. And, even if the danger is small, overuse of antibiotics in livestock can decrease the drugs’ effectiveness in humans.

The Kennedy-Snowe bill would require the U.S. Food and Drug Administration to withdraw the approval of non-therapeutic use of eight classes of antibiotics within two years, if the animal drug use is not proven harmless to people. It would also require the manufacturers of animal drugs and medicated feed to make available records of their sale so the Centers for Disease Control will have better usage data and be better able to track resistance trends.

This bill is a good first step in stopping a growing problem. However, humans also must use fewer antibiotics. Demanding immediate cures for the common cold and other viral ailments has prompted doctors to write increasing numbers of prescriptions for antibiotics.