BEIJING • As many as half of China's breeding pigs have either died from African swine fever or been slaughtered because of the spreading disease, twice as many as officially acknowledged, according to the estimates of four people who supply large farms.

While other estimates are more conservative, the plunge in the number of sows is poised to leave a large hole in the supply of the country's favourite meat, pushing up food prices and devastating livelihoods in a rural economy that includes 40 million pig farmers.

"Something like 50 per cent of sows are dead," said Dr Edgar Wayne Johnson, a veterinarian who has spent 14 years in China and founded Enable Agricultural Technology Consulting, a Beijing-based farm services firm with clients across the country.

Three other executives at producers of vaccines, feed additives and genetics also estimate losses of 40 per cent to 50 per cent, based on falling sales for their companies' products and direct knowledge of the extent of the deadly disease on farms across the country.

Losses are not only from infected pigs dying or being culled, but also farmers sending pigs to market early when the disease is discovered nearby, farmers and industry insiders have told Reuters.

Pork prices began rising substantially last month and the agricultural ministry has said they could surge by 70 per cent in coming months as a result of the outbreak. Pork accounts for more than 60 per cent of Chinese meat consumption.

China, which produces half the world's pork, last month said its sow herd declined by a record 23.9 per cent in May from a year earlier, a slightly deeper drop than for the overall pig herd.

Sows, or adult females bred to produce piglets for slaughter, account for roughly one in 10 pigs in China. A decline in the sow herd usually equates to a similar drop in pork output, industry experts say.

The Ministry of Agriculture and Rural Affairs did not respond to a fax seeking comment on claims of much higher losses than officially reported.

It said on June 24 that the disease has been "effectively controlled", state news agency Xinhua reported.

African swine fever, for which there is no cure and no vaccine, kills almost all infected pigs, though it does not harm people. Since China's first reported case last August, it has spread to every province and beyond China's borders, despite measures taken by Beijing to curb its advance. The virus is similar to the strain found in recent years in Russia, Georgia and Estonia.

The government has reported 137 outbreaks so far, but many more are going unreported, most recently in southern provinces such as Guangdong, Guangxi and Hunan, according to four farmers and an official recently interviewed by Reuters.

China had 375 million pigs at the end of March, 10 per cent fewer than at the same time a year ago, according to the National Bureau of Statistics. There were 38 million sows, a decline of 11 per cent on the year, the bureau said.

Beijing has repeatedly called for farmers to restock, but putting new sows on a farm that has been infected with African swine fever is risky, say experts. The virus can survive for weeks outside a host, potentially living on at a farm that has not been thoroughly disinfected.

REUTERS