China is flying in record numbers of pigs to improve genetics and boost productivity while rapidly rebuilding the nation’s hog population after it was decimated by African swine fever.

Some 15,346 live swine worth $32 million arrived by air in the first nine months of the year, customs data show. That’s an all-time high, according to Genesus Inc., an international genetics company. The value jumped from $3 million in all of 2019, $13 million in 2018 and $21 million in 2017, the customs data show. China has also imported a record volume of meat this year to ease pork shortages.

Denmark, France and the U.K. are among suppliers of breeding stock acquired by Chinese farms to rebuild their herds.

The hog population is recovering: the number of breeding sows rose 28% from a year earlier to 38 million by the end of September, according to the National Bureau of Statistics. Many farms kept sows for breeding purposes, many of them originally used for meat and less productive, according to Lin Guofa, a senior analyst at Bric Agriculture Group.

Jiangxi Zhengbang Technology, one of the country’s top 10 hog breeders, plans to fly in more breeding stock, increasing its total imports to 10,000 hogs by June from nearly 5,000 so far this year, the company told investors late on Wednesday.

China has allowed imports of live swine stock from Chile and Finland and resumed imports from the U.S. this year, according to customs data. The U.S. was China’s largest supplier in 2018 and 2017, the data showed.