Determining where to cut antimicrobial use for dairy calves

Stock photo, 2015.

All livestock producers have been urged to cut unnecessary antibiotic use, to try to prevent resistant bacteria from developing in their herds and flocks.

But on the farm, the question is where, and how?

Consider dairy calves, for example. More than half of the deaths of dairy calves are from diarrhea. Producers often treat that condition with antibiotics, as soon as they detect it. They’re concerned that delaying treatment could harm calf health and welfare.

But a University of Guelph research team says methodic management — in particular, using practices such as oral electrolyte replacement and water, when calves are dehydrated from diarrhea — can provide better results. They’ve found antimicrobials are required just a fraction of the time.

The team members, from the Ontario Veterinary College, have created a flow chart or algorithm (see below) to help guide producers’ decisions about treating diarrhea with antibiotics.

They are one of the first research teams to investigate the effectiveness of protocols to reduce and refine antimicrobial treatment in pre-weaned calves.

“Use of the algorithm for treatment of diarrheic calves reduced antimicrobial treatment rates without a negative impact on their health,” says lead researcher and professor, Scott Weese.

Weese says antimicrobial therapy is commonly recommended for diarrhea regardless of its cause, to try to eliminate the suspected pathogen that’s causing the problem.

But to some extent, almost all calves get diarrhea.

“We don’t need to treat them all with antibiotics; there are other ways,” he says. “Antibiotics may not be beneficial, and in fact may lead to longer recovery times, because besides killing pathogens, they’re also killing the beneficial bacteria in the gut.”

Working for a year with two Ontario dairy farms with a total of 1,200 calves, the researchers found antibiotics were seldom a necessary treatment for diarrhea. In fact, by adhering to the algorithm they created, they cut antimicrobial use by a whopping 80 percent, with no consequences.

On the test farms, the researchers found that with good management, calves usually got better, in time. Mostly, those measures centred around fluid replacement. Fluid losses during diarrhea are significant, but the current go-to treatment of antibiotics doesn’t fix fluid losses.

“Antibiotics are important if the calves have an infection outside their intestines,” he says. “But if the infection is inside their intestines, don’t use antibiotics to try to help the calf get better. You can save yourself money…we’ve shown that the algorithm works. ”

This research has recently been expanded to include 10 Ontario farms. Weese feels the flow chart will work for farmers outside Ontario, as well.

Research sponsors were the Ontario Ministry of Agriculture, Food and Rural Affairs, and the Dairy Farmers of Ontario.

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