In the pig farming industry, sows are the “core assets” of a pig farm, and their production performance directly determines the farm’s capacity, costs, and economic returns. Empirical farming data from the past decade show that the lifetime productivity of efficient, healthy sows can be more than 30% higher than that of inefficient sows. They can also significantly reduce farming losses and improve offspring quality and farming profits. By contrast, retaining inefficient sows continuously takes up housing, feed, and labor resources, creating a vicious cycle of “high input, low output, and low quality”—a key obstacle to improving farm quality and efficiency. Scientifically culling inefficient sows and optimizing the structure of the sow herd are key measures for reducing costs and improving efficiency on modern large-scale pig farms. This article examines breed characteristics, health, reproductive performance, resilience, and offspring meat quality, among other aspects, and identifies the types of inefficient sows that should be culled, providing practical guidance for precise selection and breeding and scientifically culling inferior animals on pig farms.
1: Sows with mixed breeds and deteriorated germplasm must all be culled
Breed is the innate foundation that determines a sow’s production potential, while pure germplasm and superior breeds are prerequisites for high productivity and quality. Industry research and breeding practices confirm that a sow’s breed purity is directly linked to reproductive efficiency, adaptability, and offspring performance. Animals with mixed germplasm have no value for continued breeding.
Liu Jianfeng’s (2026) research on pig breeding indicates that three-way and multi-way crossbred or backcrossed sows with mixed genetic backgrounds and deteriorated hybrid vigor have problems such as unstable reproductive performance and significant segregation of germplasm traits. They should not be retained for breeding and should be prioritized for culling. The National Pig IndustryTechnologySystem (2021) also states in its cost-saving and efficiency-improvement plan that large-scale pig farms should completely cull inefficient sows produced through multi-way crossbreeding and backcross improvement, retaining only high-quality purebred Landrace and Large White sows, two-way crossbred sows, and approved breeding-line sows, in order to optimize the herd’s genetic structure.
Crossbred sows are mainly characterized by atypical breed traits and unstable inheritance of traits. They cannot reliably pass on superior germplasm genes. They not only have low production capacity themselves, but also cause inconsistent growth rates and a sharp decline in production performance among their offspring. Keeping them long term leads to overall deterioration of the herd’s germplasm, making them the first animals to cull when optimizing a pig farm’s herd.
2, and sows with poor health should be firmly culled
Health is essential to a sow’s continued production. Sows with intractable diseases, limb defects, or organ damage have much shorter production cycles and pose extremely high breeding risks, so they are not worth retaining. Multiple pathological studies on pig farming show that diseases and limb problems account for more than 70% of sow culling reasons, making them a major cause of low-efficiency production capacity (Liu Jingshun and Wu Zhenfang, 2019). In their breeding study of the Wenshi WS501 pig line, Wu Zhenfang et al. (2019) specified culling criteria for sows with disease-related issues: sows with congenital reproductive-organ abnormalities, a narrow pelvis, or habitual dystocia; sows whose limb and hoof diseases do not respond to prolonged treatment and that are unable to mate, walk, or farrow normally; and sows infected with serious contagious diseases, or with common diseases that remain unresolved after 2 treatment coursesTreatmentand fail to recover must all be firmly culled. At the same time, PMC global pig-farming statistics show that disease-related factors result in an average annual sow culling rate of 4.8%. Diseased sows not only experience a sharp decline in their own lactation and estrus and mating capacity, but can also readily spread infectious diseases among pigs on the farm, increasing disease-prevention and control costs. In addition, sows with chronically poor condition, an imbalanced body condition, or excessive fatness or thinness that cannot be corrected through feeding adjustments have disrupted metabolism and declining reproductive function, and should likewise be culled as low-efficiency animals.
3, low-producing sows with persistently poor reproductive performance should be culled decisively
Reproductive performance is a core indicator of a sow’s value. Measures such as lifetime litter size, healthy piglet rate, estrus and mating efficiency, and lactation capacity directly determine a pig farm’s core production capacity. Long-term empirical data show that the lifetime farming benefits of high-producing and low-producing sows can differ by more than ten thousand yuan. Persistently low-producing sows are the greatest source of wasted resources on a pig farm. The industry standardBreeding pigsCulling criteria are clear: sows with extremely poor lactation capacity and fewer than 8 live-born piglets over 2 consecutive litters must be culled. Sows that are not affected by boars or environmental factors, but fail to conceive for 3 consecutive estrous cycles or do not come into estrus within 60 days after weaning, must also be culled. Field trial data from Liu Jianfeng (2026) further refine the culling thresholds: replacement sows with fewer than 10 healthy piglets in their first litter, multiparous sows with fewer than 12 healthy piglets, and breeding sows showing no improvement for 2 consecutive litters, as well as older sows whose productivity has declined sharply after 6 or more litters, should all be culled promptly. A longitudinal study of large-scale pig farms by PMC (2022) found that reproductive disorders and persistently low productivity account for 29.32% of all sow culls. These sows use farm resources without generating corresponding returns; retaining them long term directly reduces the farm’s overall production capacity and profitability.
4, vulnerable sows with poor stress resilience and weak adaptability: cull them without hesitation
A sow’s stress resilience refers to its overall ability to adapt to environmental fluctuations, disease-related stress, and production demands. It directly affects the sow’s productive lifespan, production stability, and the farm’s ability to withstand risks. Sows with poor stress resilience are highly prone to production stoppages, illness, and abortion in response to stressors such as temperature changes, regrouping, farrowing, and disease, resulting in very poor production stability.
Multiple studies on stress resilience in pigs show that sows with excellent stress resilience can have a breeding lifespan extended by more than 57 days, an increase of 0.3 in the number of productive parities, and a significant improvement in lifetime productivity (PMC, 2024). In contrast, sows with weak stress resilience may develop irregular estrus, abortion, stillbirths, abrupt cessation of lactation, or complete loss of appetite in response to even mild stress, leaving very little room for production setbacks. Based on farming practice, two types of sows with low stress resilience should be prioritized for culling: first, sows that adapt poorly to their environment and remain unadapted and unproductive for a prolonged period after seasonal changes, regrouping, or feed adjustments; second, sows with weak disease resistance that become ill frequently, are prone to secondary infections, and are susceptible to common diseases such as PRRS and mycoplasma, with little ability to recover without treatment. These sows are highly unstable producers; in addition to their own low productivity, they also substantially increase the farm’s costs for feeding and disease prevention and control,Treatmentcosts, severely affecting the stability of herd production.
5, sows whose offspring have poor meat quality and inferior traits should be culled promptly
Modern pig farming has long shifted from “emphasizing quantity” to “giving equal importance to quantity and quality.” Sows determine not only the number of piglets born but also directly affect the meat quality and carcass traits of their offspring through maternal genetic effects. Authoritative breeding research has confirmed that key pork quality indicators, including intramuscular fat, water-holding capacity, tenderness, and muscle fiber characteristics, are significantly influenced by maternal effects (Huang Lusheng’s team, 2025). Crossbreeding experiments in pigs by Shu Gang et al. (2015) show that maternal breed and germplasm traits directly determine key meat quality indicators in offspring, such as intramuscular fat content and meat tenderness. Offspring of inferior maternal stock commonly have coarse-textured meat, poor water-holding capacity, and insufficient flavor. Other research has confirmed that sows carrying inferior PRKAG3 and PHKG1 genes are more likely to produce offspring with inferior meat quality, such as excessive glycogen content and acidic meat, substantially lowering pig carcass grades and market prices (PMC, 2020). In practical breeding, any sow whose offspring commonly show slow growth, an imbalanced lean-meat percentage, coarse-textured meat, or a high rate of carcass defects for 2 consecutive litters must be culled decisively, regardless of how many piglets she produces. These sows have genetic defects in their germplasm and will continue to produce low-quality pigs, reducing the market competitiveness of the farm’s products and falling short of the development needs of modern high-quality pig farming.
Culling sows is not about blindly clearing the herd. It is a scientific, standardized, and ongoing selection process based on genetics, health, productivity, resilience, and offspring quality. Sows with mixed or poor genetics, chronic health problems, low reproductive efficiency, poor resilience, or offspring with inferior meat quality are five categories of animals that represent key bottlenecks to improving farm productivity and quality, and must be accurately identified and decisively culled. Pig farms should establish a routine sow screening and culling mechanism, taking into account both academic research standards and their own farming conditions. They should regularly identify low-productivity individuals and continuously optimize herd structure to build a core sow herd that is “high-producing, healthy, consistently productive, and high-quality.” This helps reduce farming costs at the source, improve productivity and efficiency, safeguard pork quality, and support stable, long-term profitability for the farm.
1: Sows with mixed breeds and deteriorated germplasm must all be culled
Breed is the innate foundation that determines a sow’s production potential, while pure germplasm and superior breeds are prerequisites for high productivity and quality. Industry research and breeding practices confirm that a sow’s breed purity is directly linked to reproductive efficiency, adaptability, and offspring performance. Animals with mixed germplasm have no value for continued breeding.
Liu Jianfeng’s (2026) research on pig breeding indicates that three-way and multi-way crossbred or backcrossed sows with mixed genetic backgrounds and deteriorated hybrid vigor have problems such as unstable reproductive performance and significant segregation of germplasm traits. They should not be retained for breeding and should be prioritized for culling. The National Pig IndustryTechnologySystem (2021) also states in its cost-saving and efficiency-improvement plan that large-scale pig farms should completely cull inefficient sows produced through multi-way crossbreeding and backcross improvement, retaining only high-quality purebred Landrace and Large White sows, two-way crossbred sows, and approved breeding-line sows, in order to optimize the herd’s genetic structure.
Crossbred sows are mainly characterized by atypical breed traits and unstable inheritance of traits. They cannot reliably pass on superior germplasm genes. They not only have low production capacity themselves, but also cause inconsistent growth rates and a sharp decline in production performance among their offspring. Keeping them long term leads to overall deterioration of the herd’s germplasm, making them the first animals to cull when optimizing a pig farm’s herd.
2, and sows with poor health should be firmly culled
Health is essential to a sow’s continued production. Sows with intractable diseases, limb defects, or organ damage have much shorter production cycles and pose extremely high breeding risks, so they are not worth retaining. Multiple pathological studies on pig farming show that diseases and limb problems account for more than 70% of sow culling reasons, making them a major cause of low-efficiency production capacity (Liu Jingshun and Wu Zhenfang, 2019). In their breeding study of the Wenshi WS501 pig line, Wu Zhenfang et al. (2019) specified culling criteria for sows with disease-related issues: sows with congenital reproductive-organ abnormalities, a narrow pelvis, or habitual dystocia; sows whose limb and hoof diseases do not respond to prolonged treatment and that are unable to mate, walk, or farrow normally; and sows infected with serious contagious diseases, or with common diseases that remain unresolved after 2 treatment coursesTreatmentand fail to recover must all be firmly culled. At the same time, PMC global pig-farming statistics show that disease-related factors result in an average annual sow culling rate of 4.8%. Diseased sows not only experience a sharp decline in their own lactation and estrus and mating capacity, but can also readily spread infectious diseases among pigs on the farm, increasing disease-prevention and control costs. In addition, sows with chronically poor condition, an imbalanced body condition, or excessive fatness or thinness that cannot be corrected through feeding adjustments have disrupted metabolism and declining reproductive function, and should likewise be culled as low-efficiency animals.
3, low-producing sows with persistently poor reproductive performance should be culled decisively
Reproductive performance is a core indicator of a sow’s value. Measures such as lifetime litter size, healthy piglet rate, estrus and mating efficiency, and lactation capacity directly determine a pig farm’s core production capacity. Long-term empirical data show that the lifetime farming benefits of high-producing and low-producing sows can differ by more than ten thousand yuan. Persistently low-producing sows are the greatest source of wasted resources on a pig farm. The industry standardBreeding pigsCulling criteria are clear: sows with extremely poor lactation capacity and fewer than 8 live-born piglets over 2 consecutive litters must be culled. Sows that are not affected by boars or environmental factors, but fail to conceive for 3 consecutive estrous cycles or do not come into estrus within 60 days after weaning, must also be culled. Field trial data from Liu Jianfeng (2026) further refine the culling thresholds: replacement sows with fewer than 10 healthy piglets in their first litter, multiparous sows with fewer than 12 healthy piglets, and breeding sows showing no improvement for 2 consecutive litters, as well as older sows whose productivity has declined sharply after 6 or more litters, should all be culled promptly. A longitudinal study of large-scale pig farms by PMC (2022) found that reproductive disorders and persistently low productivity account for 29.32% of all sow culls. These sows use farm resources without generating corresponding returns; retaining them long term directly reduces the farm’s overall production capacity and profitability.
4, vulnerable sows with poor stress resilience and weak adaptability: cull them without hesitation
A sow’s stress resilience refers to its overall ability to adapt to environmental fluctuations, disease-related stress, and production demands. It directly affects the sow’s productive lifespan, production stability, and the farm’s ability to withstand risks. Sows with poor stress resilience are highly prone to production stoppages, illness, and abortion in response to stressors such as temperature changes, regrouping, farrowing, and disease, resulting in very poor production stability.
Multiple studies on stress resilience in pigs show that sows with excellent stress resilience can have a breeding lifespan extended by more than 57 days, an increase of 0.3 in the number of productive parities, and a significant improvement in lifetime productivity (PMC, 2024). In contrast, sows with weak stress resilience may develop irregular estrus, abortion, stillbirths, abrupt cessation of lactation, or complete loss of appetite in response to even mild stress, leaving very little room for production setbacks. Based on farming practice, two types of sows with low stress resilience should be prioritized for culling: first, sows that adapt poorly to their environment and remain unadapted and unproductive for a prolonged period after seasonal changes, regrouping, or feed adjustments; second, sows with weak disease resistance that become ill frequently, are prone to secondary infections, and are susceptible to common diseases such as PRRS and mycoplasma, with little ability to recover without treatment. These sows are highly unstable producers; in addition to their own low productivity, they also substantially increase the farm’s costs for feeding and disease prevention and control,Treatmentcosts, severely affecting the stability of herd production.
5, sows whose offspring have poor meat quality and inferior traits should be culled promptly
Modern pig farming has long shifted from “emphasizing quantity” to “giving equal importance to quantity and quality.” Sows determine not only the number of piglets born but also directly affect the meat quality and carcass traits of their offspring through maternal genetic effects. Authoritative breeding research has confirmed that key pork quality indicators, including intramuscular fat, water-holding capacity, tenderness, and muscle fiber characteristics, are significantly influenced by maternal effects (Huang Lusheng’s team, 2025). Crossbreeding experiments in pigs by Shu Gang et al. (2015) show that maternal breed and germplasm traits directly determine key meat quality indicators in offspring, such as intramuscular fat content and meat tenderness. Offspring of inferior maternal stock commonly have coarse-textured meat, poor water-holding capacity, and insufficient flavor. Other research has confirmed that sows carrying inferior PRKAG3 and PHKG1 genes are more likely to produce offspring with inferior meat quality, such as excessive glycogen content and acidic meat, substantially lowering pig carcass grades and market prices (PMC, 2020). In practical breeding, any sow whose offspring commonly show slow growth, an imbalanced lean-meat percentage, coarse-textured meat, or a high rate of carcass defects for 2 consecutive litters must be culled decisively, regardless of how many piglets she produces. These sows have genetic defects in their germplasm and will continue to produce low-quality pigs, reducing the market competitiveness of the farm’s products and falling short of the development needs of modern high-quality pig farming.
Culling sows is not about blindly clearing the herd. It is a scientific, standardized, and ongoing selection process based on genetics, health, productivity, resilience, and offspring quality. Sows with mixed or poor genetics, chronic health problems, low reproductive efficiency, poor resilience, or offspring with inferior meat quality are five categories of animals that represent key bottlenecks to improving farm productivity and quality, and must be accurately identified and decisively culled. Pig farms should establish a routine sow screening and culling mechanism, taking into account both academic research standards and their own farming conditions. They should regularly identify low-productivity individuals and continuously optimize herd structure to build a core sow herd that is “high-producing, healthy, consistently productive, and high-quality.” This helps reduce farming costs at the source, improve productivity and efficiency, safeguard pork quality, and support stable, long-term profitability for the farm.