The use of plant extracts, once dismissed as quack science, is attracting growing interest from the industry. Dr Henry Greathead, researcher at the department of biology, is experimenting with essential oils from thyme as a treatment for coccidiosis, a disease of chickens currently controlled with in-feed antibiotics.

"Antibiotics are excellent growth promoters, and the ban will put EU farmers at a competitive disadvantage with producers elsewhere, so we are trying to find sustainable alternatives," said Greathead.

"Plant extracts are natural and their production would help ensure a diverse agriculture. Above all they are acceptable to the consumer."

Another University project is investigating the use of extracts from garlic and aniseed to increase digestive efficiency in dairy cows. Plant extracts may also replace the use of growth-promoting hormones, which are used to boost animal production in many countries, but are banned in the EU.

"It's unlikely that plant extracts alone will ever be as effective as antibiotics, but I'm confident that we can maintain high levels of production with good husbandry - and without needing antibiotics and steroids."