Before this round of pork price surges, China's pork prices had flattened out at low levels for more than two years and farmers were forced to reduce the scale of hog raising because it was not profitable.

"This round of pork price rises has also come from external factors that pig farmers and enterprises cannot control," said Zhang, referring to the spread of African swine fever and the environmental control policies by some local governments. "The combination of the two factors has led to sharp decreases in the numbers of pigs and sows."

As African swine fever spreads, pig farmers and enterprises have become more alert and taken measures to prevent it.

"The government, industrial associations and ourselves have taken time to learn how to control the spread of the disease and now we are more experienced and more capable, both in terms of methodology and equipment, to control it," said Wang of the Jilin University pig farm.

Wang said his farm has increased frequency of disinfection and keeps more disinfection equipment in store so that the procedure will not be interrupted by dysfunctional equipment.

Many newly built pig farms have had equipment, such as that used for ventilation and automatic dung clearing, installed so that the improved living environment would help improve the immune systems of the pigs to help prevent infection, Wang said.

Some local governments that had forbidden pig raising in the name of environmental protection, meanwhile, are revising their policies, Zhang of the CASS said.