"I spend a lot of time with my Friesians and they definitely 'moo' with a Somerset drawl," he said, referring to the breed of dairy cow he owns.

"I've spoken to the other farmers in the West Country group and they have noticed a similar development in their own herds.

"I think it works the same as with dogs - the closer a farmer's bond is with his animals, the easier it is for them to pick up his accent."

Dom Lane, spokesman for a group called the West Country Farmhouse Cheesemakers to which Green belongs, said it contacted John Wells, Professor of Phonetics at University College London, who said that a similar phenomenon had been found in birds.

"You find distinct chirping accents in the same species around the country. This could also be true of cows," Wells said on the group's Web site (www.farmhousecheesemakers.com).

According to Lane, accents among cows probably develop in a similar way as among humans, and resulted from spending time with farmers with differing accents.

"Apparently the biggest influence on accents is peer groups - on children in the playground, for example," he said. "Herds are quite tight-knit communities and don't tend to leave the area."

He added that more scientific research was needed to prove what was just an anecdotal theory at this stage.