Without much fanfare, American poultry producers this year announced that they have stopped feeding antibiotics to healthy birds for growth promotion.

"Tyson Foods and other poultry companies weren't feeding near the amount of antibiotics that the detractors were claiming," explains Ed Nicholson, spokesperson for Tyson Foods, which leads the poultry industry with sales of 216 million pounds of chicken annually. "We felt that needed clearing up."

Still, the announcement is extraordinary. For more than 20 years, U.S. poultry producers have resolutely defended the use of all antibiotics in chicken production. Even as recently as this past summer, when Russia cited antibiotic use as a reason to ban U.S. poultry imports, the industry stood behind its production practices.

And this turnaround isn't just for the birds. The National Pork Board has announced it will use checkoff funds to support five research projects dealing with alternatives to sub-therapeutic antibiotic use in weaned pigs. Subtherapeutics are usually used to prevent or decrease the incidence of bacterial diseases and to cause improvements in productivity of food-producing animals.

Consumers at work. The use of antibiotics in food animals has been worrisome since the 1970s, when the Food and Drug Administration (FDA) first called for restrictions on antibiotics in animal feed. Debate heated up after 1995 when fluoroquinolones-considered one of the most valuable drug classes available to treat human infections-were approved for poultry. FDA has been trying since 2000 to ban a chicken drug called Baytril, which is similar to Cipro, the human drug that is used to treat anthrax in humans, as well as food-borne illnesses like Salmonella.

"The antibiotic-resistance issue has been building for a long time," says Liz Wagstrom, director of veterinary science for the National Pork Board. "What's different now is there is increasing pressure from consumer activist groups that are well organized and extremely well funded."

Most notable is the Keep Antibiotics Working group, which has launched a full-fledged media blitz to end the use of medically important antibiotics for humans in food animals. The Sierra Club has also started a new campaign this year to inform consumers about antibiotic use in food animals and promote farms that raise animals without routine use of antibiotics or additional hormones.

"The only way corporate agriculture will stop abusing your medicine is if you demand meat raised without routine usage of antibiotics," Kendra Kimbiauskas, organizer for the Sierra Club's Antibiotics in Agriculture project, told a group of supporters at the club's first antibiotic-free barbecue in July.

Corporate consumers, like McDonald's and Wendy's, have further raised consumer attention to the antibiotic resistance issue by refusing to buy chicken that has been treated with certain types of antibiotics.

Not black or white. Adding frustration to the antibiotic-resistance issue is lack of definitive evidence that antibiotic use in food animals leads to human resistance. "Honestly, we don't know what the exact contribution of antibiotics in food animals is to the overall problem of resistance in humans," says Dr. John Rosenblatt, infectious disease specialist at the Mayo Clinic in Rochester, Minn., and spokesperson for the Sierra Club's antibiotic-free livestock campaign.

"But even if it is only a small percentage, the situation does need to be improved," Rosenblatt says.

The pork industry is beginning to question just how much antibiotic is really needed in an animal's diet, Wagstrom says. "We have increasing evidence that in some of our modern facilities it may be a good idea to research what exactly the benefits of growth-promoting antibiotics are in certain situations," says Wagstrom.

Even though subtherapeutic antibiotics, like tetracycline, are approved as safe for use in beef cattle, producers are moving away from feeding them in an effort to prevent disease, says John Paterson, beef specialist at Montana State University.

"We just don't see our producers feeding a lot of subtherapeutics," says Paterson. "If there is a sickness like pneumonia or foot rot, they'll hit the cattle hard with a therapeutic injectable antibiotic and clear it up."

Economics is also helping drive the shift away from feeding subtherapeutic antibiotics, says Dennis Erpelding, corporate manager for Elanco Animal Health. "Economically, producers are not going to use antibiotics if they don't have to," Erpelding says. "They are becoming more interested in other preventative production practices."

Regulation on the horizon. Ultimately, opponents hope Congress will legislate a phaseout of subtherapeutic antibiotics fed to food animals. Rep. Sherrod Brown, D-Ohio, has already introduced such a bill in the House, which would phase out non-therapeutic agricultural use of eight specific antibiotics-including penicillin and tetracycline-in farm animals over two years.

The bill would be "a devastating blow to animal health while providing little public health benefit," and would "strip veterinarians and livestock and poultry producers of important products used to treat, control and prevent animal disease and produce a safe food supply," according to a statement by the Coalition for Animal Health, which includes the Animal Health Institute, American Association of Swine Veterinarians, American Veterinary Medical Association and American Feed Industry, as well as major livestock organizations.

A ban on feed-grade antibiotics could increase pork production costs by about $6 per head within 10 years, reports an Iowa State University study. However, with higher live hog prices because of a resulting smaller pork supply, researchers estimate net profit would only drop by 79¢ per head over a 10-year period.

Wagstrom noted that no matter what the outcome of the current legislation, FDA is in the process of developing new standards for registering animal antibiotics. The administration is creating a framework, or set of guidelines, to assess the human risk of animal antibiotics as they come to market. FDA plans to use this framework to license new food-animal drugs, says Wagstrom, and to go back and look at existing licenses. "It's just not an easy issue," Wagstrom says. "The livestock industry has to do what is right for public health, but not to the point we don't use science to make good decisions."