Politics rather than science is behind European moves to limit key antibiotics from veterinary use to protect their efficacy in humans.
Speaking at the British Mastitis Conference, Worcester, Declan O'Rourke of Ortec Consultancy said the link between on-farm use and resistance in human pathogens was unlikely.
"However the reality is that this issue is now driven by politics," he said.
"In the EU, a reported 25,000 deaths are put down to antibiotic resistance and the passing of bacteria such as E coli from farm to fork.
"The question is how many, if any, of these deaths were related to the fact an antibiotic produced in an animal led to resistant bacteria being transferred to a human?"
He referenced a Scottish report which had looked at Salmonella typhimurium DT104 in 1990-2004.
"While ecologically connected, animals and humans have distinguishable DT105 communities," he said.
"It is unlikely that the local population is responsible for the diversity of resistanceobserved in humans. However, this does not let us off the hook," he stressed.
He stated that the Dutch government's "knee jerk reaction" to reduce antibiotic use by 70% by 2015 had no science behind it. However to avoid similar knee-jerk legislation, vets and farmers had to be prepared to take the lead.
"We need to not only demonstrate responsible use of antibiotics on farm but use science and system development to reduce veterinary intervention," he said.
BOX: Antibiotic reduction in Denmark
By advising farmers not to treat chronic cases of mastitis, the Danes have reduced intramammary antibiotic use in lactating dairy cows by 22%.
Jens Yde Blom of Biosens said when a cow had at least two repeat cases of mastitis, a farmer was advised to either cull the animal or treat via dry cow therapy (DCT). This fitted with the Danish Cattle Federation's aim to reduce antibiotic use in dairy cows by 30% by 2015.
"At the last milk recording, a couple of weeks before drying off, a farmer can test chronic cows to select candidates for DCT," said Dr Yde Blom.
As a result of this reduction in lactation intramammary use, there had been a 5% increase in dry cow therapy in Denmark. The total kilos of active antibiotics use was also down 3% and use of 3rd and 4th generation cephalosporins had decreased by 38%.
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