U.S. regulators are asking drug companies to phase out the use of certain antibiotics intended to improve the growth of livestock.
Critics have long argued the practice is contributing to the worldwide antibiotic resistance crisis.
Large-scale livestock farms around the world often use small doses of antibiotics to help healthy animals grow faster with less feed. Public health experts say the practice encourages bacteria to become resistant, making the drugs less effective in fighting infections.
FDA Deputy Commissioner Michael Taylor says the new measure would end that practice over the next three years and require a veterinarian to write a prescription for other uses.
"With these changes, there will be fewer approved uses, and the remaining uses will be under tighter control to minimize the impact on resistance."
Advocates say it is a good first step; but, they note the measure is voluntary and question how many companies will comply.