In Vietnam, large-scale pig farms are leading the adoption of innovations and progressing through initial digital transformation stages. This transition is expected to reshape the livestock sector by reducing the dominance of disease-vulnerable smallholder farms, promoting sustainable and biosecure production(Qui et al., 2025);(Zhu et al., 2023). Technological applications such as microclimate monitoring(Gao et al., 2022) and artificial intelligence (AI) are increasingly integrated to ensure optimal housing, detect abnormal behaviors, monitor health parameters(Balthazar et al., 2025);(Reza et al., 2025), enable early disease detection(Bordignon et al., 2025);(Reza et al., 2025), and facilitate rapid outbreak response. Furthermore, automation minimizes human-animal interaction, limiting pathogen transmission and mitigating stress caused by frequent human presence in intensive settings(Bossert & Coeckelbergh, 2024);(Williams et al., 2024).

Despite these advances, the rapid adoption of digital systems raises concerns regarding animal welfare (freedom from hunger and thirst, freedom from discomfort, freedom from pain, injury or disease, freedom to express normal behavior, and freedom from fear and distress) in intensive pig production globally(Herlin et al., 2021). Overemphasis on productivity can increase stress(Karaer et al., 2023);(Michielon et al., 2024), adversely affecting physiological balance and ultimately compromising pork quality(Gagaoua et al., 2025);(Ogawa et al., 2024). Studies show animal welfare improvements have a nonlinear relationship with productivity(Morgado et al., 2023), depending on the degree of enhancement and linked to the animal’s physiological responses(Riesner et al., 2025).

Restricted space allowance is a major welfare issue, escalating competition for resources(Camp et al., 2021);(Chidgey, 2024), elevating aggression, and promoting skin lesions and lameness(Camp et al., 2021);(Vermeer et al., 2017). Gilts, in particular, may sustain more severe injuries than mixed-sex groups(Angela et al., 2023) due to factors like higher growth rates(He et al., 2019).

Stress, whether from an adverse environment or management, activates neural and endocrine pathways(Lee et al., 2024). While acute stress causes increased blood cortisol and abnormal behavior(Lee et al., 2024), chronic stress exerts long-term physiological impacts, including suppressed immune function and altered lipid metabolism(Lomax et al., 2013). Cholesterol is central as a precursor(Salisbury et al., 2023);(Zhang et al., 2019) for steroid/reproductive hormones (testosterone, estradiol, and cortisol steroid hormones (testosterone, estradiol, cortisol), vitamin D, and bile acids(Celso & Elise, 2024);(Ma et al., 2024), essential for homeostasis, reproductive function, and lipid metabolism. Prolonged stress is linked to reduced lymphocyte count and altered monocyte quality(Maydych et al., 2017), leading to impaired immune function(Alotiby, 2024);(Dhabhar, 2014). Consequently, growth indicators such as average daily gain (ADG) are reduced(Rodrigues et al., 2024);(Silpa et al., 2025), and slaughter age is delayed(Hultgren et al., 2022);(Terlouw & Gagaoua, 2023).

Given these challenges, achieving a balance between production efficiency and animal welfare is critical for the modern pig industry. Especially in rapidly digitalizing Vietnam, integrating welfare assessment into management is essential for sustainable development and improved meat quality. Therefore, the present study was designed to evaluate the welfare status (good feeding, good housing, good health, and appropriate behavior) of finishing pigs (aged 124 - 156 days) and assess post-slaughter meat quality indicators across farms of different production scales.

Restricted space allowance in most commercial pig production systems and industrial limits the animals’ ability to move freely and express natural behaviors. In the present study, the average space provided for finishing pigs (126-154 days old) ranged between 0.4 and 0.6 m² per pig (Gonçalves Vero et al., 2023), which is considerably lower than the recommended standard of 0.8-1.2 m² per pig established by welfare guidelines(Kim et al., 2016). Such confinement conditions can increase competition for space, feed, and water resources, leading to heightened stress and aggressive interactions among pigs.

One common management practice contributing to welfare challenges is regrouping, particularly during the transition from the nursery to the growing-finishing stage(Coutellier et al., 2007). Pigs originating from different litters are frequently mixed according to similar age or body weight(Angela et al., 2023), which often provokes fighting behavior as animals attempt to establish new social hierarchies(Clavell-Sansalvador et al., 2024). These confrontations may result in skin lesions(Clavell-Sansalvador et al., 2024), leg and hoof injuries(Boyle et al., 2022), and negative emotional states, such as fear or avoidance of human contact(Lecorps et al., 2020), which can be observed through behavioral changes within pens.

Furthermore, several painful husbandry and management procedures are still routinely implemented across farms of all sizes, probably due to preventive measures. Among these, tail docking remains a common practice to mitigate the risk of tail biting(Valros, 2024) during the growing-finishing period(D’eath et al., 2014). However, findings from this study demonstrated that this management intervention contributed to one of the lowest welfare scores under the criterion “absence of pain induced by management procedures.” This outcome reinforces concerns that routine invasive practices can adversely affect animal welfare, emphasizing the need for refinement or replacement with less painful alternatives.

In recent years, many large-scale pig production systems have adopted modernized, biosecure housing models to reduce the risk of infectious diseases such as African Swine Fever (ASF). One common innovation is the implementation of zero-discharge slatted floor systems(Butucel et al., 2022);(Witkowska & Ponieważ, 2022), which aim to minimize water usage and wastewater generation. These systems help maintain lower humidity levels within barns(Han et al., 2024);(Mosquera et al., 2019) and effectively limit the proliferation of pathogenic microorganisms, including bacteria and fungi that thrive in moist environments(Cheng et al., 2024);(Haq et al., 2024). However, despite their biosecurity advantages, such systems may pose potential welfare challenges. In addition, the accumulation of manure or urine on the animals’ bodies, due to infrequent washing or inadequate drainage, can cause pigs to develop skin irritations or diseases and dermatological disorders/coughing symptoms(Chen et al., 2024);(Duniere et al., 2024). Thus, these factors may be associated with the relatively low scores observed for the “absence of disease” criterion in large-scale farms.

Nutritional management also plays a crucial role in maintaining welfare outcomes across production scales. Understanding the nutrient requirements of pigs at different growth stages allows farms to maintain relatively consistent body condition scores (BCS) (3.5-4.5 points per maximum of 5) in finishing herds(Moniruzzaman et al., 2023);(Song et al., 2025). Additionally, most large-scale farms ensure sufficient nipple drinkers that provide continuous and unrestricted access (ad libitum) to clean water. Therefore, the “good housing” principle consistently achieved higher ratings, reaching the enhanced welfare level across scales. Furthermore, large-scale farms are also more likely to invest in modern housing designs, such as enclosed housing systems (EHS), which provide improved environmental control compared with conventional indoor housing (IHS)(Delsart et al., 2020). For example, Song et al. (2011)(Song et al., 2025) reported that the EHS facilities maintained summer temperatures between 24.8 and 29.1 °C, while conventional barns exhibited wider fluctuations (up to 7.6 °C) with peaks of 32.3 °C. Such temperature stability is essential for maintaining animal comfort and productivity.

Moreover, most large-scale pig farms operate under integrated commercial or contract farming models, where companies collaborate with farmers through structured production and marketing agreements(Thawee et al., 2024). In contrast, small-scale farms often lack comprehensive feed planning(Thawee et al., 2024), resulting in inconsistent feed quality or occasional shortages(Thawee et al., 2024). Many large-scale farms have established contracts with feed mills, supported by silo storage and automated feeding systems, ensuring both feed consistency and efficiency(Miller et al., 2023);(Thawee et al., 2024). As a result, pigs raised under large-scale systems may exhibit minor differences in chemical composition and nutritional value compared with those from smaller farms.

From a meat science perspective, stress-induced physiological changes affect muscle glycogen reserves, which play a key role in post-mortem glycolysis and meat quality. Depletion of glycogen prior to slaughter limits lactic acid production, leading to high ultimate pH and the development of dark, firm, and dry (DFD) meat(Kiyimba et al., 2024);(Terlouw et al., 2021). In contrast, acute pre-slaughter stress accelerates glycolysis, causing rapid glycogen breakdown and excessive lactic acid accumulation while carcass temperature remains high, resulting in protein denaturation, reduced water-holding capacity, and the formation of pale, soft, and exudative (PSE) meat(Ma et al., 2022);(Michelle et al., 2024);(Ogawa et al., 2024). Numerous studies have demonstrated the antimicrobial and antioxidative properties of plant-derived compounds, which can enhance gut health, immunity, and overall growth performance. The incorporation of herbal extracts not only supports disease resistance but also contributes to improved meat quality indicators, particularly in terms of lipid profile. In fact, the antimicrobial ability of various herbal extracts has been well-documented in numerous studies(Hemeg et al., 2020), primarily due to the natural bioactive compounds present in plants, which contribute to improved animal health(Njimoh et al., 2015) and reduced disease incidence(Alem, 2024);(Guo et al., 2024). Phytogenic additives play an important role as natural antioxidants, helping to reduce oxidative stress and improve meat quality(Orzuna-Orzuna et al., 2024);(Orlowski et al., 2018). These bioactive compounds are associated with increased proportions of unsaturated fatty acids (such as linoleic, linolenic, and arachidonic acids) and a higher UFA/SFA ratio, aligning with the growing consumer preference for healthier, nutritionally balanced pork products.

The assessment results indicated that large-scale pig farms achieve higher standards in animal welfare principles, specifically regarding feeding and housing management, compared to medium and small-scale farms. However, health status and behavioral indicators remain relatively consistent across all production scales. In terms of meat quality, while large-scale farming influences certain quality traits, the overall differences in chemical composition and water retention properties among the scales are not substantial. These findings suggest that although large-scale production systems may provide relatively more consistent environmental management and feeding practices, their potential advantages in meat quality were limited under the conditions of the present study.