China 2021 – African swine fever second wave and breeding sow herd losses
Enforcement Action
In Effect
January 1, 2021
Summary
In late 2020 and the first half of 2021, China experienced a renewed resurgence of African swine fever (ASF) outbreaks — commonly described by analysts as a “second wave” — involving new variant strains and, in some cases, vaccine-derived strains associated with unapproved ASF vaccine use. Independent market analysts estimated that approximately 7–8 million breeding sows died in the six to eight weeks prior to early March 2021, a figure representing an estimated 25% of USDA’s official beginning sow stock estimate for China. Provincial data documented negative sow inventory recoverability in at least 13 provinces in 2021. One large commercial producer reported a 7.5% sow herd decline — approximately 90,000 sows — between December 2020 and February 2021 due to ASF and associated culling. In response, MARA issued a Hog Production Capacity Control Implementation Plan (Provisional) setting a national target of approximately 41 million breeding sows with a retention floor of 37 million, and an April 2021 regional prevention and control work plan restricting pig movements between provinces. This record covers the 2021 second-wave sow losses; the initial 2018–2019 outbreak and herd collapse is documented in a separate Development record.
Background Context
China’s first ASF outbreak was confirmed on 3 August 2018 in Liaoning Province and subsequently spread to all 32 provincial-level regions, causing large declines in the national pig herd and breeding sow inventory through 2019. From late 2019 through 2020, central and provincial authorities introduced subsidies, rebuilding incentives, and biosecurity measures to restore pig and sow inventories, aiming to recover pre-ASF capacity by approximately mid-2021. By December 2020, MARA projected that the pig and sow herds would be fully recovered by the first half of 2021. This projection formed the baseline that the second wave disrupted. Technical and media analyses associated the resurgence with continued ASF virus circulation, emergence of new variant strains, use of unapproved or illegal ASF vaccines particularly in some large-scale breeding operations, and uneven biosecurity implementation.
System Impact
Direction
Reduces Exploitation
Type
Changes Scale
Significance
High
ASF outbreaks and associated sow mortality and culling were documented across multiple provinces in northern and northeastern China from late 2020 into the first half of 2021. Provincial data show negative sow inventory recoverability in at least 13 provinces in 2021, including major producers Henan and Shandong. One large publicly listed pig producer reported its sow herd declined approximately 7.5% — approximately 90,000 animals — between December 2020 and February 2021 due to ASF infection and herd culling. Analyst estimates, not confirmed by official MARA data, put total sow losses in the second wave at approximately 7–8 million in the six to eight weeks prior to early March 2021. Pork production volumes declined during the period of acute herd losses, generating price movements; some substitution toward poultry and other protein sources occurred during periods of pork shortage. In response, MARA issued the Hog Production Capacity Control Implementation Plan (Provisional) in 2021, setting national targets of approximately 41 million breeding sows with a floor of 37 million, and provincial authorities were directed to adjust sow numbers toward this range. An April 2021 Work Plan for Regional Prevention and Control of ASF and Other Major Animal Diseases imposed movement restrictions on pigs between provinces, limiting long-distance transport to breeding pigs, piglets, and pigs originating from ASF-free zones. By 2022, reported official outbreak counts had decreased substantially relative to the early epidemic years.
Anticipated Effects
If MARA’s 2021 Hog Production Capacity Control Implementation Plan is implemented as written across all provinces, breeding sow numbers in China would be managed within a band of approximately 37–41 million, which would condition future pig production scale and may moderate extremes of over-expansion or rapid contraction in response to future disease shocks.
If the April 2021 regional prevention and control work plan functions as designed, restrictions on pig movements between regions would be expected to constrain between-region ASF transmission and concentrate long-distance transport in lower-risk categories, reducing future outbreak spread risk.
If illegal and unapproved ASF vaccine use is effectively curtailed and official biosecurity controls are strengthened across large-scale breeding operations, subsequent ASF-related sow mortality in future waves would be expected to be reduced relative to the 2018–2021 period.
The acute sow losses of the 2021 second wave were followed by renewed herd rebuilding under the capacity-control framework; whether the Chinese breeding sow herd returned to or stabilised within the 41-million target range within the 14th Five-Year Plan period is not established within the scope of this record.
Significance Rationale
Assigned Reduces Exploitation (impact direction) based on documented breeding sow mortality and culling during the second-wave resurgence: analyst estimates of 7–8 million sows lost in approximately six to eight weeks; company-level disclosure of 90,000 sow losses at one large producer; and academic documentation of negative sow inventory recoverability in 13 provinces in 2021. The primary quantitative figure (7–8 million sows) is an industry analyst estimate rather than an official MARA numerical release and should be treated as indicative rather than verified.
Assigned Changes Scale (impact type) because the primary mechanism is breeding sow mortality and disease-control culling directly reducing the reproductive foundation of China’s pig production system. The breeding sow population is the multiplier base for future production capacity; losses at this scale carry consequences for pig numbers beyond the immediate death count.
Assigned High significance because the estimated losses — if accurate — represent approximately 25% of USDA’s beginning sow stock estimate for China in 2021, disrupting herd rebuilding plans across 13 provinces and generating documented national-level market and price effects. The scale change is transitional: the acute sow losses occurred within a discrete period in early 2021 and were followed by renewed rebuilding efforts under the MARA capacity-control framework; the Chinese pig production system did not permanently contract as a result of the second wave.
Key Actors
The Ministry of Agriculture and Rural Affairs (MARA) issued the Hog Production Capacity Control Implementation Plan (Provisional) and the April 2021 regional prevention and control work plan, and oversaw national ASF surveillance and control. Provincial agricultural and rural affairs departments implemented local disease control, culling, movement controls, and herd-rebuilding measures in line with MARA’s national framework. WOAH received official outbreak notifications via Chinese reporting channels. One large commercially listed pig producer reported a 7.5% sow herd decline — approximately 90,000 animals — in Reuters coverage of April 2021. Independent analysts including meat analyst Simon Quilty (quoted by ABC News), the American Farm Bureau Federation, USDA, OECD, and the Asian Development Bank documented second-wave dynamics and production impacts. Technical analyses by researchers at Chinese and international institutions documented variant strain emergence and biosecurity failure as contributing factors.
Editorial Correction Notice
Development date: Set to 1 January 2021 as a placeholder. The second-wave peak mortality and culling period is described in sources as occurring over approximately six to eight weeks before early March 2021, placing the onset around January–February 2021. No single confirmed trigger date is available; the placeholder should be updated if a specific dated outbreak notification or MARA announcement can be identified as the primary anchor event.
Scale & Prevalence: The figure of 7–8 million sows lost is an analyst estimate (attributed to meat analyst Simon Quilty via ABC News and the American Farm Bureau) and has not been confirmed by an official MARA numerical release. It should be treated as indicative rather than verified. The company-level figure of approximately 90,000 sows (7.5% herd decline) is drawn from Reuters and constitutes a named corporate disclosure rather than an official aggregate. Official MARA statistics on sow inventory changes during the 2021 second-wave period would provide the authoritative basis for this field and should be consulted before this record moves to Review.
Development type: Classified as Enforcement Action rather than Trade & Market Change because the primary development mechanism is disease-control enforcement — culling and movement restriction by veterinary and agricultural authorities — rather than a market-driven supply chain shift. The market and price effects are documented consequences of the enforcement action, not the development itself.
Current status: The acute second-wave period is historical (late 2020 – first half 2021). In Effect reflects the continuing ASF control framework and capacity-control plan rather than the ongoing operation of the second-wave sow losses specifically.
Related record: The initial 2018–2019 ASF outbreak and national pig herd collapse is documented in a separate Development record. The capacity-control plan (MARA 2021) could constitute a discrete Government Policy record if sufficient primary source documentation is available; currently documented in this record’s anticipated effects.
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