If you want to sum up the debate over antibiotics in food animals, try this – the more we expose organisms to antibiotics in animals, the more opportunity there is for them to develop resistance to those antibiotics and, ultimately, to affect human health.

That linear thinking has been the source of decades of debate about whether or not, or to what extent, antibiotics should be used in animals. At the center of the debate is the use of low-level antibiotics for growth promotion and feed efficiency.

Here’s the rub: “While it’s plausible, there is simply no hard evidence that connects human cases of infection with a resistant bacteria and the use of antimicrobials in animals,” says Ron DeHaven, American Veterinary Medical Association (AVMA) executive vice president. “Further, there is little evidence at this point to suggest that eliminating or greatly reducing the use of antimicrobials in food animals improves human health or results in less antimicrobial resistance in humans.”

He points to Denmark as an example. That country banned the use of antibiotics for growth promotion and feed efficiency in pigs in 2000. Following the ban, Danish hog produces reported significant animal health problems, particularly in the early stages. As a result, veterinarians had to resort to greater use of therapeutic doses of antibiotics to maintain animal health and welfare.

“That ban has been in place for quite some time and yet there has been no improvement in terms of the increased frequency of antimicrobial resistance seen in humans,” DeHaven says. “Indeed, some evidence suggests there’s been an increasing prevalence of antimicrobial-resistant infections in people since the ban.”

A Closer Look: Is Solving The Antibiotic Resistance Dilemma Possible?

That suggests a number of things, he says, not the least of which is that there may be a therapeutic response to subtherapeutic use of antibiotics.

Nonetheless, U.S. politicians and regulators are forging ahead, seeking to limit the use of antibiotics in food animal production.

DeHaven says the FDA Center for Veterinary Medicine, the regulatory body over antibiotic use, recognizes and supports the importance of antibiotics in animals for control and prevention of disease. “Long term, they would like to see a phase in of greater veterinary oversight and a phase out of growth promotion and feed efficiency use,” he says. “In the meantime, we need data to see if, in fact, the benefit we’re seeing in terms of growth promotion and feed efficiency is because we’re seeing a therapeutic benefit from the use of antibiotics given in low doses to large numbers of animals.”

So what’s ahead? Likely, it’s more veterinary oversight on all antibiotic use and an eventual reduction in flexibility, if not an outright ban, of low-level antibiotics in feed and water. While AVMA supports more veterinary oversight of antibiotic use, DeHaven says the group does have some workforce concerns.

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Those concerns revolve largely around limitations in the number of rural veterinarians to carry out the needs of greater veterinary oversight. If you have to wait on your veterinarian to write a prescription for an antibiotic before you head to the feed store, the delay could result in greater animal suffering and increased disease incidence as the bugs spread through your herd.

DeHaven says FDA will likely use the existing Veterinary Feed Directive as the vehicle to impose more regulations on antibiotic use in food animals. The directive essentially calls for a veterinarian’s prescription to use antibiotics in feed and water. “We do have workforce concerns, hence the need for more flexibility in how we apply the Veterinary Feed Directive,” he says.