this is the Agriculture Report.Regulators in the United Statesare asking companies that make antibiotic drugsto tell farmers to stop usingsome of the drugs on livestock.Antibiotics are medicinesuse to fight bacteria and infections.Large animal farms around the worldoften use small amount of antibioticsto help healthy animals grow faster with less feed.They put the antibiotics in the food and waterthey give to cows, chickens and pigs.Opponents of this use of antibiotic sayit adds to worldwide resistance to such drugs.Public health experts say,using an antibiotic on an animal gives bacteria the chanceto built double defense against the drug.This makes antibiotics less effectivewhen they are used to fight diseases in humans.Last month, the U.S. Food and Drug Administrationasked drug companies to voluntarily change the wordson the containers of antibiotics so far use in farm animals.Michael Taylor is the agency's Deputy Commissioner."With these changes, there will be fewer approved uses,and the remaining uses will be under tighter controlto minimize the impact on resistance," said Taylor.The decision by the FDA to askrather than order the drug companies to make the changeshas angered some activists.But the FDA said, changes would be made more quicklyif it ask the drug companies to voluntarily changehow they use antibiotics.Dimitri Drekonja is a doctorwith the Infectious Diseases Society of America.He supports the FDA's decision to ask for voluntary changes,but he is not sure the drug companieswill do what the agency has asked."If this voluntary effort is taken upby the entire industry and everybody goes along with it,then it will actually be a needed firstand potentially last step.Will that happen? I have my doubts," Drekonja added.Some large drug companies have already agreed to make the changes.Liz Wagstrom is the Chief Veterinarianat the National Pork Producers Council.He says the pig farming industryis preparing for a change in the way it uses antibiotics,even it will cost some farmers money."We may lose some efficiency.We may have some animals that may not grow quite as quicklyor take more grain to reach their full weight, " said Wagstrom.She also says the changes may meanfarmers will have more sick animals.Doctor Drekonja says it may be difficult to measurehow the new policy affects drug resistances."It would be great if there was sort-of like a dashboardand you could watch the needle drop in the amount of antibiotics used and then watch the next gauge,which is the national resistance and see what happens there.We don’t have two simple gauges like that," Drekonja says.He says there is a lack of good informationon the amounts of antibiotics used on farms, as well as by doctors.Some bacteria have continued to be resistant to drugs for yearseven after they have been banned from animal use.But doctor say they have been taking more stepsto limit their use of antibiotics with humans,and they believe farmers should do the same.And that's the Agriculture Report.