Meristem: Beef Science

Research is helping Canada's beef industry strengthen the management of antimicrobial drugs, to reduce resistance issues and producer cost while supporting animal health.

"Finding ways to reduce reliance on antimicrobials is not an easy thing, but it's clear that's direction the industry has to move," says Dr. Tim McAllister, beef cattle researcher at Agriculture and Agri-Food Canada's (AAFC) Lethbridge Research Centre.

"We have the knowledge today to manage animals better. We know about handling procedures that minimize stress. And we know about a range of animal management practices in the feedlot, including dietary strategies, that can minimize the risk of disease without adding major cost to production. Employing those practices can go a long way toward reducing reliance on antimicrobials."

Research is focused on helping provide producers with further options, says McAllister. For example, scientists are exploring nutritional strategies, such as proper dietary introduction when cattle first enter the feedlot. "That alone could greatly reduce the need for antimicrobials," he says.

McAllister discusses the research effort to strengthen antimicrobial strategies in a new, "Perspectives on Beef Science" article on the Meristem Land and Science Web site, www.meristem.com. Land and Science is a service featuring information on the sustainability of agriculture, food production and the environment. It is presented by Meristem Information Resources Ltd., in co-operation with partners in agriculture, food, environment and life sciences.

Because antimicrobials are employed in some cases to boost animal performance through behaviour such as higher feed intake, a key focus for researchers is understanding more about this potential effect, says McAllister, a veteran rumen microbiologist and nutritionist.

"If we know more about how specific antimicrobials affect feeding behavior, we can better determine if they have value as performance enhancers," he explains. "If they don't, that provides further rationale for reducing use. If they do, we can then look for other feed additives or management practices that can produce the same benefit."

Antimicrobial drugs administered to cattle have long played a critical role in animal health, helping to ensure a strong supply of safe, high-quality beef.

But their use has faced increasing scrutiny, particularly as administering antimicrobials at sub-therapeutic levels to healthy animals has become routine practice to prevent animal health problems in an easy-to-manage way and to promote animal growth.

"The fact is, the more an antimicrobial is used, the more pressure it places on the microbes it targets to evolve and eventually become resistant. That process reduces the effectiveness of the antimicrobial, leaving producers potentially with new, more difficult animal disease concerns and less options for treating sick cattle."

Concern has also risen that antimicrobial use in cattle production may contribute to the development of resistant microbes that threaten human health. An extensive study, funded by the Canada Alberta Beef Industry Development Fund (CABIDF) and completed in 2004, thoroughly examined this question.

While this study ruled out several major concerns and found no immediate human health threats linked to cattle production practices, researchers cautioned antimicrobials must be used judiciously to minimize the potential for future issues relevant to both animal and human health.

Meristem "Perspectives" articles and reports are an ongoing series designed to bring to light various important perspectives on issues critical to sustainable agricultural, food and environmental systems.

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Research champions new approach to antimicrobials for beef industry