British Prime Minister David Cameron was in China for the past three days for a trip that has seen some controversial moments. However, there's at least one clear success: The United Kingdom has signed a deal to export porcine semen to China that will net British farmers a reported £45 million ($73 million) a year.

Yes, pig sperm.

According to a report in the Guardian, beginning next year British pigs will be taken to one of four artificial insemination centers in the U.K. and their semen will then fly to China (either frozen or fresh) and be used to inseminate the Chinese pig population.

Big trades of sperm may seem unusual, but in the world of pig farming this makes complete sense. The Chinese pork industry is staggeringly huge — more than half of the pigs in the world are believed to live in China and it is a major source of protein for Chinese citizens — but the industry is out of date and inefficient. Incredibly, despite its huge pig population, China became a net importer of pork in 2008.

British pigs could help. Not only is their meat considered high quality (for example, Berkshire pork, one of the most lauded varieties in the world, originates in the U.K.), it's a world leader in breeding economical pigs: Chris Jackson, export manager of the British Pig Association, told the Financial Times that British pigs can grow faster than their Chinese counterparts, and they eat less food and reproduce quicker. Amazingly, the cost of a pig in the U.K. is reported to be half that of one in China.

Crucially, the deal is a big win for British pork farmers, who have struggled domestically for years. The industry is reported to net around £300 million ($490 million) a year, but that's down from double that a decade ago, and pork prices are severely constrained by supermarket shoppers' demands for cheap meat. Sperm is one way to make money off high-quality pigs without affecting the domestic supply, and there are broader hopes within the U.K. agricultural industry that Britain could turn itself into something like the Saudi Arabia of sperm, selling its "liquid gold" not only from pigs, but also from cattle and sheep, to China and other places all around the world.

There's another neat detail to the U.K.-China deal too: Pig trotters (feet) may be next. Stewart Houston, chairman of the British Pig Executive, told the FT that semen was a "big deal" but "nothing compared with the trotters." While pig trotters aren't commonly used in British cuisine, they are considered a delicacy in China — in October a Chinese official was suspended after racking up bills totaling 700,000 yuan ($115,000) at a pig trotter restaurant over three years. The U.K. government believes trotters, essentially waste products in Britain, could net U.K. farmers £7.5 million ($12 million) a year if an agreement is made.