The British government is looking to expand the ties between the UK and China through pigs (Reuters)

Britain will export quality pig semen to China as part of a £45m a year deal struck during Prime Minister David Cameron's trade trip to the world's second largest economy.

Half of the world's pigs are in China but there are concerns about the quality of the country's stock, which could be improved by doing business with pig farmers in Britain.

"We're doing all we can to ensure that businesses up and down the country reap the rewards from our relationship with China," said a spokesperson for No 10.

"And that includes our pig farmers. This new deal to export pig semen will be worth £45m to UK firms and means Britain's best pigs will help sustain the largest pig population in the world."

Four UK artificial insemination centres, based in England and Northern Ireland, will start making preparations for the exports in the new year.

Environment Secretary Owen Paterson, who is accompanying Cameron, is also negotiating a deal to export pig trotters to China as they are a delicacy there.

"And we're not stopping there, we're talking to the Chinese about serving up pigs trotters on Beijing's finest dining tables. That would be a real win-win - a multimillion pound boost for Britain and a gastronomic treat for Chinese diners," the spokesperson added.

In 2012, Paterson successfully persuaded Russia to accept British beef exports.

Paterson is now understood to be looking at exporting parts of slaughtered chickens to China, in a move which could be worth £70m ($114m, €84.4m) a year to British farmers.