Superbugs may be passed on to humans through undercooked meat, a report has warned.
The use of antibiotics in farming must be reduced because it represents a critical threat to public health, the Government-commissioned Review on Antimicrobial Resistance said.
Among the risks from widespread use of drugs in agriculture is that drug-resistant infections could be transferred from animals to humans eating undercooked meat, the review led by Government antibiotics tsar Jim O'Neill claimed.
Consumption of antibiotics by animals is greater than that by humans in many countries around the world, Lord O'Neill said, describing the finding as "staggering".
The trend poses a risk that the so-called superbugs will develop and spread, whether through direct contact between humans and animals, consumption of undercooked meat, or from animal waste, the report said.
A phased reduction of antibiotics in agriculture is recommended in the latest proposal by the review, suggesting countries could have agreed limits on their use over the next 10 years.
The report, entitled Antimicrobials in agriculture and the environment: reducing unnecessary use and waste, also calls for strict standards around industrial pollution, ensuring as little manufacturing waste as possible is released into the environment.
Last month researchers in China identified a gene that makes infectious bacteria such as Escherichia coli (E.coli) highly resistant to polymyxins, the last group of antibiotics left after all others have failed.
The discovery in China, described as "extremely worrying" by one scientist, suggests the gene can easily be transferred to bacteria with the potential to cause epidemics.
An E.coli strain showing resistance to the polymyxin drug colistin was isolated from an intensively-farmed pig in Shanghai during routine testing.
Lord O'Neill said: "I find it staggering that in many countries most of the consumption of antibiotics is in animals, rather than humans. This creates a big resistance risk for everyone, which was highlighted by the recent Chinese finding of resistance to colistin – an important last-resort antibiotic which has been used extensively in animals.
"As we've highlighted, most of the scientific research provides evidence to support curtailing antibiotic use in agriculture, it's time for policy makers to act on this. We need to radically reduce global use of antibiotics and to do this we need world leaders to agree to an ambitious target to lower levels, along with restricting the use of antibiotics important to humans."
The review is expected to present further proposals on how to deal with antimicrobial resistance early next year.