A small number of the UK’s dairy farms account for an outsized proportion of antibiotic use, according to new research, suggesting that closer scrutiny of antibiotic prescribing practices could help bring down their use.

A study published in the BMJ publication Vet Record found some farms were using “extremely high levels” of antibiotics in their cattle. While most of the dairy farms surveyed showed lower than average use compared with the averages for all livestock reared in the UK, some outlying farms with high levels of use stood out.



The researchers were unable to pinpoint why this small number of farms should exhibit such high use, but said that identifying these hotspots and the reasons their administration of the drugs is so high could prove a big help in reducing antibiotic use.



The use of antibiotics in farming is of increasing concern. On Wednesday, M&S and Waitrose for the first time published data on the use of the medicines in their farming supply chain, showing that both were below the industry average in their usage.

Antibiotics are more widely used in farming than in human health, in the UK and around the world, and experts are worried that the over-use of such medicines could be imperilling human health, by encouraging the growth of resistant bacteria.

The chief medical officer for England, Dame Sally Davies, has repeatedly said that the rapidly increasing resistance to antibiotics and the rise of resistant “superbugs” is one of the greatest threats to human health, which could make even routine operations life-threatening in future. The World Health Organisation called earlier this year for the strongest antibiotics to be banned from use on farms, owing to the likelihood that their use in agriculture would result in them becoming ineffective in human medicine.

Data on antibiotic use in farming is hard to find, as the government collates only national level statistics on the tonnage of the medicines used, rather than breaking it down into finer detail that might reveal prescribing practices across sectors and geographically.

The new study examined 358 dairy farms over a 12-month period, including more than 81,500 cows in its sample – about 7% of all the dairy cows in England. Most of the drugs used were administered by injection.

In the study, the top 25% of farms used just over half – about 52% – of the total antibiotics used across the sample. It is not known why this small number of farms accounted for such high usage.

The researchers said their work should provide a benchmark for future studies of antibiotic use. The called for “targeting the reduction of antibiotics among the minority of high users, while maintaining high standards of health, welfare and production [as a] fast and effective first step to reduce [antibiotic use] at farm, practice and national levels.”

Lucy Coyne, a veterinarian at the University of Liverpool, said the work was timely and welcome and provided insight into how antibiotic use could be reduced. “Through improved antimicrobial use data and a continuation of a united and proactive approach, there should be confidence in the UK dairy sector achieving the reduction target by 2020.”

The government said last month that sales of antibiotics to treat animals in the UK had fallen by 27% in the two years from 2014 to 2016. There was also a drop of 83% in sales of colistin, an antibiotic of last resort that is critical for human health,