Antibiotics: Reviewing your use on farm

Dairy Australia's National Animal Health and Welfare Lead, Dr Stephanie Bullen, is encouraging Australian dairy farmers to review how they use antibiotics when treating their animals.

World Antimicrobial Resistance Awareness (AMR) Week running from 18-24 November, and Dr Bullen says that it's a good time to reflect on any opportunities to improve how things are done.

"All users of antibiotics, including dairy farmers, have a responsibility to use antibiotics appropriately," she says.

"They are a critical tool to ensure the welfare of sick animals, but inappropriate and overuse of antibiotics leads to the development of resistance.

"This is when bacteria no longer respond to the antibiotics used to treat them and some infections may become impossible to treat."

AMR is a major risk to both animal and human health. It has been declared a global health emergency and one of the top 10 global health threats by the World Health Organisation (WHO).

WHO data indicates that the number of human deaths attributed to AMR are expected to surpass those caused by cancer by 2050 unless urgent action is taken to address the development of AMR.

Consequently, Dr Bullen is recommending farmers to focus on two specific antibiotics, ceftiofur (e.g. Excenel, Excede, Accent) and virginiamycin (Eskalin).

"These antibiotics belong to essential classes of antibiotics for human health in Australia. Maintaining access to them for treating sick animals is a priority for us, but we must act now to prevent the development of resistance, spillover from dairy animals to people, food and the environment or risk having them removed for use in animals entirely."

Salmonella case study

Dr Rob Bonanno - a Gippsland dairy cattle veterinarian and herd health consultant with decades of experience working in both Australia and internationally - agrees.

Dr Bonanno described a case of multi-antibiotic-resistant Salmonella in dairy calves on a clients' farm. The farm was experiencing high levels of disease despite very high use antibiotics, and the owner engaged Dr Bonanno seeking a 'stronger' antibiotic.

"Instead of dispensing antibiotics, we performed diagnostics to determine the cause. We cultured Salmonella from multiple sites of dead calves on post-mortem and it was resistant to all the antibiotics that were being used, including Excenel [ceftiofur]," Dr Bonanno explains.

"On farm, we improved colostrum management, targeted vaccination to reduce scours, respiratory infections and the Salmonella, improved hygiene and stopped feeding red herd milk."

"Once these were going well and the hygiene and environmental challenges were improved, miraculously no antibiotics were needed, and mortality rates dropped so significantly that the farm had surplus heifers to sell."

Dr Bonanno says that aside from the obvious animal welfare and economic benefits of improving antibiotic use, he is concerned about the potential risk to workers or family members being infected with a multidrug resistant infection such as Salmonella.

"Wouldn't you hate to have a child hospitalised from a multi resistant bacterial infection and know that you might have contributed to that? That's why I care about this issue," he says.

'As little as possible, as much as necessary'

Specialist veterinarian in cattle medicine, Associate Professor John House from the University of Sydney Livestock Veterinary Teaching and Research Unit, supports Dr Bonanno. "The best antibiotic is the one that stays on the shelf," Associate Professor House says.

"Antibiotics are the stop gap to mitigate losses and compromised welfare while work is done to determine why the underlying problem started and to implement strategies to prevent disease in the first place.

"Ceftiofur should never be used for common conditions without conducting laboratory testing to determine if other lower importance antibiotics may be equally effective."

While Dr Bonanno still prescribes ceftiofur and virginiamycin on clients' farms, he adopts an 'as little as possible, as much as necessary' approach.

"There are examples of necessary use of these antibiotics in acute situations. But they should never be used as a crutch for poor management," he says.

The good news is that overall, the current level of AMR on Australian dairy farms is very low.

"However, it's just so important we keep it that way for the sake of our animals, our kids, and the generations to come," Dr Bullen says.

For more information on using antibiotics appropriately, visit our Antimicrobial Resistance page.

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