BEIJING, Jan 17 (Reuters) - China produced 57.94 million metric tons of pork in 2023, highest in at least a decade, official data showed on Wednesday, after farmers ramped up slaughter in the last quarter to cut losses amid an oversupply of pigs and an outbreak of African swine fever.

Annual pork output expanded 4.6% from a year ago.

Production in the fourth quarter was at 14.93 million tons, according to Reuters calculations of the data from the National Bureau of Statistics, up 7% from the same quarter of 2022.

The surge in production came as pig enterprises, struggling with a downturn in demand after an aggressive expansion in recent years, faced pressure to cut back on breeding herds and sell farms.

Farmers are also attempting to reduce the impact of a recurring outbreak of African swine fever that has plagued China for years. An initial wave killed millions of pigs in 2018 and 2019.

China’s largest hog breeder Muyuan Foods Co sold 6.6 million hogs in December, up 25% from November and 10% from a year ago, it said in a filing. Second-largest breeder Wen’s Foodstuff Group Co said it sold 2.97 million hogs in December, up 15% from the previous month and up 58% from a year earlier.

The national pig herd dropped 4.1% during 2023 to 434.22 million head, the National Bureau of Statistics, according to the data. (Reporting by Mei Mei Chu; Editing by Tom Hogue)