As almost any parent of small children can attest, ear infections are becoming harder to treat. Amoxicillin was once the drug of choice to cure the common childhood ailment. But its widespread use has allowed bacteria to adapt to and resist the drug. Now more expensive drugs are often needed to kill the bacteria that cause ear infections. There are even more troubling examples of antibiotic overuse as doctors have reported an increase in antibiotic-resistant tuberculosis and salmonella.

The overuse of antibiotics, long considered wonder drugs for treating once fatal illnesses, is also a problem in livestock where pigs, chickens and cows are routinely fed the drugs to speed growth and stave off illness. The drugs are also added to animal feed to make up for unsanitary conditions.

This could change thanks to Sen. Olympia Snowe and Democrat Edward Kennedy of Massachusetts who will introduce a bill this week to limit the nontherapeutic use of antibiotics in livestock. “We can’t afford to squander the healing power of miracle drugs by allowing them to be used indiscriminately in farm animal feed,” Sen. Kennedy said last week.

The Union of Concerned Scientists estimates that only 10 percent of the 22 million pounds of antibiotics used annually on livestock is for medical treatment. The rest is used to promote growth. The group estimates that the nontherapeutic use of drugs in livestock has increased 50 percent since 1985.

Last month, McDonald’s, one of the world’s largest buyers of meat, announced that it was asking its suppliers to reduce their use of growth-enhancing antibiotics. While other restaurant chains and companies are likely to follow suit, a federal law limiting such use will speed the elimination of the practice.

The Snowe-Kennedy bill would require the U.S. Food and Drug Administration to withdraw the approval of nontherapeutic 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.

The bill also authorizes the secretary of agriculture to make payments to defray the costs of farms transitioning away from the medicines’ use with a priority given to small and family farms. Finally, the bill includes grants to colleges and universities to establish demonstration projects highlighting alternatives to antibiotics for achieving the same goals.

While the bill is likely to be opposed as unnecessary by agriculture officials, the evidence shows that antibiotics overuse in farm animals is a problem that needs to be addressed now. Sen. Snowe’s bill is an important first step.