The U.S. Food and Drug Administration for the first time released an estimate on the amount of antibiotics sold for use in domestic food animal production, a move that comes as the agency aims to curb the growth in antibiotic resistance.

The agency estimates that, in 2009, there were just shy of 29 million pounds sold for use in animal agriculture.

“That’s a lot,” as Maryn McKenna, infectious disease journalist and author of “Superbug,” put it on her blog for Wired magazine last week. But, Mckenna notes, it’s not necessarily more or less than was expected, in part because the current estimates vary so wildly.

Though the debate over routinely feeding antibiotics to food animals has grown louder–and has been featured more in the mainstream media–the report was released with no fanfare and has been widely ignored by most news organizations.

McKenna broke the news on her blog, aptly titled ‘Superbug.’

“The reason why antibiotic use on farms is a concern,” says McKenna. “[I]s because such use stimulates the emergence of drug-resistant organisms that move off the farm in animals, in groundwater, in dust, on the wind and in the systems and on the clothes of those who work there, and makes new resistance factors available to be swapped among bacteria.”

Out of these concerns–which have been raised by a variety of consumer, science, and public health groups–leadership at FDA has indicated that the agency will take a serious look at ways to curb resistance by looking at the overuse of antibiotics–in both animal agriculture and human medicine.

“Because more use of antimicrobials is, in general, associated with greater levels of resistance, these data will supplement the FDA’s ongoing activities in antimicrobial resistance prevention,” the FDA reported.  “It also reinforces a recent agency draft guidance on the judicious use of certain antimicrobials in food-producing animals.”

The agency released a draft guidance on judicious use in animal agriculture in June “intended to help reduce the development of resistance to medically important antimicrobial drugs” that are still used widely in food animal production to ward off disease and promote growth.

The document states that the overall weight of evidence supports “the conclusion that using medically important antimicrobial drugs for production or growth enhancing purposes (i.e., non-therapeutic or subtherapeutic uses) in food-producing animals is not in the interest of protecting and promoting the public health.”

The animal health industry has long maintained that antibiotics are a critical tool for animal health and that any move to limit use should be based on science.

“For more than 40 years, antibiotics approved by the Food and Drug Administration have been used to treat sick animals, prevent illness and maintain the health of animals,” the Animal Health Institute, a veterinary industry group, states on its website.  “Livestock and poultry producers rely on these products so they can provide U.S. consumers with the safest food possible.”