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Open Veterinary Journal, (2026), Vol. 16(8): 5077–5095

Review Article

10.5455/OVJ.2026.v16.i8.5

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Optimizing the thermal environment for piglets in farrowing houses: A comprehensive narrative review

Nombuso N. Nkosi, Peter A. Idowu, Khathutshelo A. Nephawe and Takalani J. Mpofu^*

Department of Animal Sciences, Tshwane University of Technology, Pretoria, South Africa

*Corresponding Author: Takalani J. Mpofu. Department of Animal Sciences, Tshwane University of Technology, Pretoria, South Africa. Email: MpofuTJ [at] tut.ac.za

Submitted: 18/11/2025 Revised: 23/06/2026 Accepted: 09/07/2026 Published: 08/08/2026

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Abstract

Optimizing the thermal environment in farrowing houses is essential for enhancing neonatal piglet survival, welfare, and production efficiency. Newborn piglets possess limited thermoregulatory capacity and low energy reserves, making them highly susceptible to hypothermia during the early postnatal period. Cold stress and crushing collectively account for up to 25% of piglet deaths within the first week of life, underscoring the importance of maintaining suitable microclimates. Despite advances in housing and breeding techniques, increasing litter sizes and variable piglet birth weights have increased the vulnerability of pigs to thermal stress. Current management practices often fail to maintain optimal temperature gradients between sows and piglets, leading to welfare concerns and productivity losses. A comprehensive literature review is required to guide evidence-based strategies for effective thermal regulation in farrowing environments. This narrative review integrates peer-reviewed studies published between 2010 and 2025 from Scopus, Web of Science, and ScienceDirect. The literature was categorized into four themes: piglet thermoregulation and physiology, environmental and housing factors, heating technologies, and maternal–offspring interactions. Key outcomes of thermal comfort, mortality, and performance were synthesized. Localized heating systems, such as infrared lamps, heated mats, and underfloor heating, effectively create microclimates that sustain optimal piglet body temperatures while avoiding heat stress. Piglets that were guided to these heat sources shortly after birth showed improved survival and growth. Sow factors, such as colostrum quality and maternal attentiveness, and piglet traits, such as birth weight and vitality, strongly influence thermoregulation and performance. Ensuring optimal thermal conditions in farrowing houses significantly reduces pre-weaning mortality and supports sustainable productivity. Adoption of localized, sensor-driven heating systems, targeted piglet assistance post-birth, and artificial intelligence-based environmental monitoring are strongly recommended to enhance survival, welfare, and efficiency in modern pig production systems.

Keywords: Neonatal survival, Piglet traits, Pre-weaning mortality, Sow traits.

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Introduction

Pig production is a significant sector of global livestock agriculture, making substantial contributions to food supply, economic development, and rural livelihoods (Mbuthia et al., 2015; Food and Agriculture Organization, 2022; Adesehinwa et al., 2024; Giglio et al., 2025; Mabunda et al., 2025). Pig farming has a broader economic impact, driving related industries such as animal feed production, veterinary care, and equipment manufacturing. Rising pork demand, advances in genetics, and housing and nutrition innovations have accelerated commercial pig farming across many regions of the world (FAO, 2022; Maher et al., 2025; McDowall and McDermott, 2025). The industry continues to expand (McGlone, 2013; Diehl et al., 2022; Vonderohe et al., 2022), and ensuring pigs’ health and productivity, particularly during their early stages of life, is vital to pig production sustainability (Vonderohe et al., 2022; Sossidou et al., 2025). Neonatal piglet mortality remains a major challenge, leading to significant economic losses and raising animal welfare concerns in pig production (Blavi et al., 2021; Farmer, 2022; Farmer and Edwards, 2022).

Thermal vulnerability is one of the underlying factors leading to early piglet mortality (Zhao et al., 2022). Newborn piglets have a high surface/volume ratio (Villanueva-García et al., 2020), limited energy reserves, and underdeveloped thermoregulatory mechanisms (Lezama-García et al., 2022; Gomes et al., 2025). Many mammals, including newborn piglets, lack brown adipose tissue and have poor insulation, making them dependent on external heat sources for survival. Piglets require a much warmer microclimate of 32°C–35°C, whereas sows are most comfortable at 18°C–22°C. Failure to meet these divergent needs within shared farrowing spaces creates management conflicts that directly influence piglet health and outcomes (Andersen and Pedersen, 2016; Lane et al., 2020; Reza et al., 2025). Cold stress at around 20°C (ambient temperatures) can reduce colostrum intake, lower growth performance, and increase hypothermia-related mortality, whereas excessive heat can impair energy balance and immunity, further compromising survival (Mota-Rojas et al., 2024). Suboptimal thermal conditions, including malnutrition and crushing, are also linked to major causes of pre-weaning death (Heldmaier, 1974; Machado et al., 2016; Hu et al., 2023; Malmkvist et al., 2025).

Therefore, efficient thermal regulation in the farrowing house is essential not only for survival but also for enhancing growth, reducing disease incidence, and improving both sow and piglet welfare (Blavi et al., 2021; Farmer and Edwards, 2022; Johnson et al., 2022; Zhao et al., 2022; Mabunda et al., 2025). Lower body weight piglets are vulnerable to cold stress due to lower body temperatures and underdeveloped thermoregulation (Villanueva-García et al., 2020). To mitigate these risks, farmers employ various heating interventions, such as radiant heaters, lamps, floor mats, and creep areas, that generate warmer microenvironments specifically for piglets (Andersen and Pedersen, 2016; de Oliveira et al., 2019; Lane et al., 2020; Opderbeck et al., 2021; Smith et al., 2021; Sutherland Ramirez et al., 2022). While such systems improve survival and growth rates, they also introduce new challenges related to energy consumption, cost efficiency, and environmental sustainability (Lane, 2019; Wang et al., 2019; Lane et al., 2020; Deeken et al., 2023; Malm, 2024). This trade-off is particularly relevant in the context of global climate change and the need to balance productivity with resource efficiency.

Despite the significance of this issue, the current literature provides disaggregated insights into the interplay between piglet physiology, thermal regulation, housing systems, and sustainability considerations (Gourdine et al., 2021). Some studies have focused on piglet survival or heating technologies; however, few comprehensively integrate these perspectives. Therefore, this review aims to synthesize the current evidence on optimizing the thermal environment for piglets in farrowing houses. This is achieved by examining the physiological and behavioral basis of piglets’ thermal needs and evaluating the impacts of suboptimal temperatures on piglets. Health, survival, and performance, assessing supplemental heating systems and microclimate management strategies, and exploring technological innovations and sustainability implications within the global pig production context.

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Materials and Methods

The review followed a narrative approach, synthesizing findings from relevant peer-reviewed studies. An electronic search strategy involved a systematic search of electronic databases. Only articles that investigated the effect of the thermal environments on pre-weaning piglets were selected. The review critically evaluated the evidence and provided a synthesis of the key findings, synthesizing areas of consensus and disagreement in the literature. Peer-reviewed journal articles, publications in English, and articles discussing the temperature in farrowing houses with a direct focus on piglet growth, health, and welfare were included. Nevertheless, editorials, opinion pieces, conference abstracts, non-English language articles, and articles not related to the temperature of the farrowing houses focusing on piglet growth, health, and welfare were excluded.

Thermal environment in the farrowing houses

The poor capacity of newborn piglets to control body temperature makes them extremely physiologically sensitive, especially in the early days of life (Bienboire-Frosini et al., 2023). In contrast to mature pigs, piglets have a poorly developed thermoregulatory system and very little body fat at birth. They are highly dependent on external heat sources to regulate their body temperature because they lack brown adipose tissue, which is necessary for producing metabolic heat. A high surface-area-to-volume ratio and thin skin also facilitate rapid heat loss through evaporation, convection, and conduction, particularly when exposed to cooler air and surfaces after birth (Curtis, 1983; Vande Pol et al., 2020; Vande Pol et al., 2021; Ramirez et al., 2022). Consequently, if proper warmth is not provided, piglets undergo a sharp and abrupt decrease in body temperature following delivery, which may result in hypothermia. Piglets experience a combination of factors, and their thermal comfort is a result of this complex interplay, not just a single thermometer reading (Fig. 1).

Recent computational and physiological models have underscored that heat loss in neonatal piglets occurs not only from thermal gradients but also from airflow turbulence and surface material interactions, which can now be predicted using Computational fluid dynamics (CFD)-based thermal mapping (Damasceno et al., 2018). These tools simulate air-surface-animal heat interactions by providing precise insights into how design modifications, such as underfloor heating or microclimate shields, can reduce cold stress zones.

The thermal environment is crucial for piglet survival and growth as it directly affects metabolic rate, feed efficiency, immunological response, and vitality (Cottrell et al., 2015). When piglets are kept within their thermoneutral zone, their energy can be directed toward growth and immunological development rather than thermoregulation. However, thermal neutrality is not a static target, but rather a dynamic process influenced by microclimate heterogeneity, sow heat load, and local airflow velocity (Li et al., 2023). Targeted ventilation systems, which provide individualized airflow directly to piglet areas, have achieved up to 77.9% reduction in ventilation energy while enhancing temperature uniformity and biosecurity in farrowing houses. This explains the need for precise, pen-level environmental control, as this condition outperforms conventional tunnel ventilation systems in optimizing thermal balance and pathogen management. Figure 2 presents the decision-making flowchart for optimizing the thermal environment of piglets in farrowing houses. This flowchart provides a structured approach for farmers to make informed decisions regarding thermal management. It starts with an initial assessment of the age of the piglets and the surrounding environmental factors. Then, it guides the farmers through a series of diagnostic questions based on piglet behavior and existing thermal parameters. Adjusting the heating strategies, considering both sow and piglet welfare and energy efficiency, is important. A continuous monitoring loop is recommended to ensure optimal and sustainable thermal environments for piglets.

Fig. 1. Effective environmental temperature (EET) and its components influencing piglet thermal comfort.

Extremely high temperatures can also compromise the welfare of piglets by causing dehydration, heat stress, and pain (Matthews et al., 2016; Pietrosemoli and Tang, 2020; Gómez-Prado et al., 2022), especially as they develop a greater capacity for heat output. Physiological indices, such as the Temperature-Humidity Index (THI) and the Equivalent Temperature Index for Sows (ETIS), are increasingly being used to assess thermal comfort not only in sows but also in piglets exposed to fluctuating humidity and radiant heat loads (Bjerg et al., 2018; Mengbing Cao et al., 2021). Integrating these indices with real-time sensors can provide adaptive feedback to control systems, ensuring that piglets remain within optimal heat zones while minimizing energy waste. Such physiological-environmental coupling explains the transition from fixed temperature control to responsive, data-driven climate management.

Additionally, computational modeling has further shown that hybrid heating systems, which combine solar energy with electric lamps, are more effective than electric lamps alone (Damasceno et al., 2018). Moreover, CFD simulations have validated that solar-assisted water heating designs maintain floor surface temperatures of approximately 27°C–28°C. This closely aligns with the thermal preference of piglets, signifying a sustainable route for heating design in tropical and subtropical regions. These results indicate that integrating renewable energy-based heating systems can significantly reduce electricity dependence while maintaining animal welfare.

The thermal environment in farrowing houses influences piglets’ survival, health, and growth performance (Machado et al., 2016; Villanueva-García et al., 2020; Zhu et al., 2020; Peltoniemi et al., 2021; Ramirez et al., 2022; Zhao et al., 2022). Newborn piglets are extremely vulnerable to cold stress during the first few days of life (Villanueva-García et al., 2020; Gómez-Prado et al., 2022; Lezama-García et al., 2022; Mota-Rojas et al., 2024). Due to their physiological limitations, piglets rely heavily on external heat sources to maintain their body temperature and prevent hypothermia (Pedersen et al., 2013; Baxter et al., 2015; Andersen and Pedersen, 2016; Opderbeck et al., 2021). The ideal ambient temperature for newborn piglets immediately after birth is between 34°C and 35°C, which lies within their thermoneutral zone (Vande Pol et al., 2021).

Fig. 2. Decision-making flowchart for optimizing the piglet thermal environment in farrowing houses.

Failure to maintain temperatures within this optimal range, especially during the first 48–72 hours of life, can lead to severe consequences, including reduced colostrum intake, weakened immune response, slower weight gain, and higher pre-weaning mortality (Vande Pol et al., 2020). The need for warmth in the neonatal period is further emphasized by the high rate of heat loss experienced by piglets immediately after birth. Piglets lose heat quickly because of wet skin, a high surface-area-to-body-weight ratio, and exposure to cooler surfaces in the farrowing environment due to a mix of environmental and physiological variables (Le Dividich and Noblet, 1981; Godyń et al., 2020). Cooling might cause hypothermia, which limits mobility and the ability to consume colostrum unless piglets are promptly dried and warmed.

Piglets dissipate heat more quickly into the environment due to their high surface area to volume ratio. Because of their modest body mass relative to surface area, more body heat can escape per unit of tissue, and their lack of subcutaneous fat reduces their ability to insulate against cold (Pedersen et al., 2013; Pardo et al., 2022). Convective and conductive heat losses have more than a tenfold cooling effect. The direct transmission of body heat to the floor occurs when pigs lie on cold, uninsulated flooring, causing conductive losses (Godyń et al., 2020; Smith et al., 2021; Ramirez et al., 2022). Meanwhile, cool air currents passing over the piglet’s body cause convective losses (Taylor et al., 2014; Godyń et al., 2020; Ramirez et al., 2022). When combined, these processes can lower the body temperature by 3°C–4°C in the first hour after farrowing if no additional heat is provided.

As the piglets grow older and their thermoregulatory abilities improve, the need for such high ambient temperatures gradually decreases (Zhu et al., 2020; Gómez-Prado et al., 2022; Ramirez et al., 2022). Due to the significant temperature mismatch between the thermal needs of piglets (34°C–35°C) and the typical farrowing house temperature (around 20°C–22°C), supplemental heating methods are essential to provide localized warmth and improve piglet survival (Pedersen et al., 2013; Baxter et al., 2015; Andersen and Pedersen, 2016; Opderbeck et al., 2021). Methods are designed to create microclimates within the farrowing pen that allow piglets to regulate their body temperature independently from the sow’s thermal environment. The integration of computational fluid dynamics-based environmental modeling, real-time physiological monitoring, and targeted ventilation represents a paradigm shift toward precision thermal management (Bjerg et al., 2018; Damasceno et al., 2018; Cao et al., 2021).

Supplemental heating methods

Supplemental heating is indispensable for neonatal piglets, whose limited thermoregulatory capacity and lack of brown adipose tissue make them highly vulnerable to hypothermia immediately post-farrowing (Romero et al., 2022). Their thermoneutral zone of 30°C–34°C is considerably higher than that of lactating sows, creating a thermal disparity that must be balanced within farrowing facilities (Malmkvist et al., 2012). Beyond simple temperature elevation, effective supplemental heating requires the creation of spatially stable, behaviorally adaptive, and energy-efficient microclimates that simultaneously accommodate the needs of both sows and piglets (Sutherland et al., 2009; Smith et al., 2019; Lane et al., 2020; Leonard et al., 2020). Selecting an appropriate supplemental heat source for piglet rearing requires a comprehensive evaluation of multiple factors to ensure optimal welfare and economic efficiency. This decision-making process should meticulously consider the heating unit’s thermal efficiency, which quantifies how effectively it converts energy into usable heat. Equally important is the efficacy of heating piglets, focusing on the system’s ability to deliver warmth directly and uniformly to the animals, thereby creating a suitable microclimate and mitigating cold stress. Furthermore, the cost and ease of maintenance and operation are crucial for long-term economic viability, encompassing energy consumption, labor requirements, and routine upkeep simplicity. Finally, the initial investment and the practical challenges associated with setting up the system, including material expenses, labor, and any necessary infrastructure modifications, are represented by the cost and ease of installation.

Traditionally, supplemental heating relies on radiant or conductive systems to generate localized warmth. Radiant systems, predominantly infrared (IR) lamps, deliver short-wave energy that uniformly warms the piglets and nearby floor surface but not the air. Conductive systems, such as heated mats or underfloor heating, transmit warmth through direct contact and maintain consistent temperature gradients across creep areas (Lane et al., 2020; Zhu et al., 2020). However, the modern approach has shifted toward precision-controlled heating, where geometry, heat flow distribution, and behavioral feedback guide system performance rather than static temperature setpoints.

The integration of advanced ventilation and heating strategies is emerging as a major innovation (Deeken et al., 2023; Khaowdang et al., 2025). Coupling targeted ventilation systems with localized heating creates a self-regulating microenvironment that maintains temperature uniformity while reducing ventilation energy (Hu et al., 2023; Kim et al., 2023; Li et al., 2023). These CFD-based systems are designed to optimize airflow and heat distribution concurrently, effectively balancing animal welfare, energy efficiency, and biosecurity.

Furthermore, solar-assisted and hybrid renewable heating systems are being tested as sustainable alternatives to fossil fuel-dependent methods (Zhu et al., 2020). Incorporating phase-change materials or solar collectors into underfloor heating configurations can sustain consistent surface temperatures even under variable climatic conditions, aligning with the drive for low-emission livestock systems. Collectively, these findings position supplemental heating as part of a broader precision thermal ecosystem, which is a concept where temperature regulation, airflow management, animal behavior, and renewable energy integration function cohesively to enhance piglet survival, welfare, and production efficiency.

Efficacy of the heating sources

Comparative studies on heating technologies have revealed limitations between radiant and conductive systems that extend beyond simple thermal efficiency. The effectiveness of any heating system depends not only on heat output but also on how it interacts with piglet behavior, stall design, and environmental management (Table 1).

Heated mats consistently maintain more stable surface temperatures and lower energy consumption than IR lamps (Lane et al., 2020; Zhu et al., 2020; Ramirez et al., 2022). Their conductive mechanism minimizes convective losses and concentrates warmth directly beneath resting piglets, thereby promoting even distribution and reducing piling behavior. In controlled trials, no differences in growth rates were observed between piglets using one or two lamps, but the energy use doubled with the two-lamp configuration (Leonard et al., 2020). On the other hand, Sutherland et al. (2009) and Smith et al. (2019) reported that compared with open lamps, semi-enclosed mats reduced overlay mortality and electricity consumption by over 45%. Collectively, these results indicate that conductive systems provide more stable and behaviorally favorable conditions while meeting sustainability targets. Nonetheless, the performance of heated mats depends heavily on operational management. Poor insulation, inadequate thermostatic control, or insufficient mat size can diminish their benefits and increase heat stratification within creep zones (Smith et al., 2019; Smith et al., 2021; Ramirez et al., 2022; Sun et al., 2024). Recent studies have advocated the integration of temperature sensors and feedback controllers to dynamically regulate mat output according to piglet activity and age (Xiang et al., 2025; Zhang et al., 2025; Cuan et al., 2026). Modern heating solutions are evolving from a constant output model to a sophisticated, demand-responsive approach to thermal regulation.

In contrast, heat lamps retain unique advantages during the immediate post-farrowing period, when rapid surface drying and localized radiant heat help prevent early hypothermia and hypoglycemia (de Oliveira et al., 2019). However, their long-term energy efficiency is limited; lamps primarily warm the air and nearby structures rather than piglets directly (Lane, 2019; Zhu et al., 2020; Malm, 2024). Some researchers (Leonard et al., 2020; Zhu et al., 2020) further note that uneven radiant fields can lead to piglet clustering beneath heat lamps, thereby increasing the risk of crushing and competitive stress. Therefore, contemporary design thinking favors hybrid strategies using radiant sources for the first 24–48 hours post-farrowing, followed by conductive or semi-enclosed heating for sustained thermoregulation. This hybridization aligns with the precision thermal ecosystem framework proposed by several researchers (Costantino et al., 2021; Li et al., 2023; Malm, 2024), where adaptive control systems harmonize localized heat, airflow, and animal distribution data to maintain both comfort and energy balance. Ultimately, the efficacy of supplemental heating must be evaluated through a multi-dimensional lens encompassing thermal stability, behavioral outcomes, biosecurity, and carbon footprint. Radiant and conductive systems should no longer be compared solely on energy metrics, but with their contribution to integrated welfare-performance-energy optimization in modern farrowing houses. Table 1 shows the different heating systems and how they enhance piglet survival and welfare.

Table 1. Effect of different supplemental heating sources on the performance and behavior of piglets.

Microclimates in the farrowing stalls

The concept of microclimates within farrowing stall crates has become an essential component of thermal management in modern pig production systems (Lane et al., 2020; Smith et al., 2021; Ramirez et al., 2022; Lucas et al., 2025). A microclimate refers to a small, localized area within a larger environment that is maintained at a specific set of environmental conditions, particularly temperature, to suit the unique needs of piglets. Localized climate is often created using supplemental heating sources such as heat lamps. Microclimates allow piglets to access a warm zone even when the ambient temperature of the farrowing house is kept lower for the comfort of the sow (de Oliveira et al., 2011). The fundamental thermal differences between the requirements of the sow and her piglets play a key role in the importance of microclimates (Wang et al., 2019; Lane et al., 2020; Ramirez et al., 2022). Newborn piglets need an ambient temperature of approximately 34°C–35°C to maintain their body temperature during the first few days of life, while lactating sows are most comfortable at around 18°C–22°C.

Maintaining the microclimate of the whole farrowing room at piglet-level temperatures would compromise the sow’s comfort and result in significant energy waste (Johnson et al., 2022). Microclimates provide a practical solution by allowing the sow to remain in a cooler environment while giving piglets access to warmer areas that support their early development and survival (Andersen and Pedersen, 2016; Lane et al., 2020; Reza et al., 2024). One of the key benefits of creating microclimates is reducing energy consumption and heating costs. Instead of heating the entire room, energy is concentrated in specific zones, such as creep areas, where it is most needed (Lane et al., 2020; Ramirez et al., 2022; Lucas et al., 2025). Microclimates improve piglet survival and growth performance. Microclimates also encourage piglets to lie away from the sow when resting, thereby reducing crushing incidents, one of the leading causes of pre-weaning deaths (Smith et al., 2019; Lane et al., 2020; Malmkvist et al., 2025). In warm microclimates, piglets are more active, nurse more effectively, and convert energy into growth rather than using it for thermoregulation (Wang et al., 2019; Sadeghi et al., 2023).

The success of a microclimate depends on several key elements, including the type of heating source, insulation quality, and floor space allocation to ensure that each piglet has adequate and consistent access to warmth (Sutherland et al., 2009; Vasdal et al., 2010; Smith et al., 2019; Ramirez et al., 2022). The heating source type is fundamental in shaping the thermal environment within the creep area. As discussed in previous sections, conductive heating sources such as heated mats offer uniform surface temperatures, encouraging piglets to spread evenly and rest comfortably (Pedersen et al., 2013). When paired with thermostatic controls, systems are particularly effective, allowing for temperature adjustment as piglets grow. Barriers, such as plastic or rubber side panels, around the microclimate zone are effective in retaining heat and shielding piglets from drafts, further stabilizing the thermal environment. Space allocation is another vital aspect of microclimate design. Each piglet must have adequate space to comfortably access the heated area without crowding. The optimal floor space per pre-weaned piglet varies across countries (Chidgey, 2024), which consequently determines the creep area microclimate size depending on the number of piglets in the litter. Ensuring sufficient space within the heated zone improves piglet distribution, reduces stress, and improves growth performance. Well-designed microclimates can significantly lower electricity use compared with uniform heating strategies, making them both economically and environmentally advantageous (Lane et al., 2020; Ramirez et al., 2022). Different farrowing system designs, such as conventional farrowing crates, free farrowing pens, and compromised designs, influence piglet survival, particularly mortality due to sow crushing. Conventional farrowing crates, which restrict the sow’s movement, are widely used to reduce the risk of piglet crushing because they limit sudden posture changes and rolling movements that can injure or kill piglets. Free farrowing pens provide the sow with greater freedom of movement, which improves sow welfare, but if not properly managed, can result in higher piglet mortality due to crushing (Baxter et al., 2018; Goumon et al., 2022; Baxter et al., 2024). Modern designs often include protective features such as anti-crush bars, sloped walls, and designated heated creep areas to encourage piglets to be away from the sow (Hales et al., 2014; Nicolaisen et al., 2019; Nevrkla et al., 2024; Pedersen, 2024). A compromise design is the temporary crating system, where the sow is confined only for the first few days after farrowing, when the risk of crushing is highest, and then released into a larger pen. The system can maintain low mortality rates while improving sow comfort in the later lactation period (Hales et al., 2014). The inclusion of well-designed microclimates, such as heated creep areas, within farrowing pens not only supports piglet thermoregulation but also reduces their need to stay close to the sow, thereby reducing crushing risk. The overall design of the farrowing environment must strike a balance between ensuring piglet safety and allowing the sow to express natural behaviors (Vande Pol et al., 2020).

Effect of cold stress on piglet health, growth performance, and behavior

Cold stress is a major environmental challenge that adversely affects neonatal piglets’ survival and productivity (Mota-Rojas et al., 2024; Lucas et al., 2025). Piglets have limited thermoregulatory ability due to their small body size, lack of brown adipose tissue, and minimal subcutaneous fat reserves. These characteristics result in rapid heat loss through conduction, convection, and evaporation, particularly in cold or drafty farrowing environments (Gómez-Prado et al., 2022; Tucker et al., 2023). A drop in body temperature immediately after birth reduces the mobility and vitality of piglets (Santiago et al., 2019). Failure of a piglet to successfully locate and suckle from the sow’s teats to ingest colostrum can subsequently lead to severe consequences such as starvation, dehydration, and a compromised immune system, increasing the risk of disease and mortality. Cold piglets tend to huddle together for warmth, often lying in proximity to the sow, which increases the likelihood of crushing incidents (Mayorga et al., 2018; Conrad et al., 2022).

Low temperatures prolong the time piglets spend lying in wet bedding or on cold surfaces, further worsening heat loss and increasing the chance of hypothermia-related mortality (Renaudeau et al., 2012). Cold stress also negatively affects piglet physiology, leading to measurable changes in body temperature, heart rate, and respiratory rate. Piglets exposed to cold environments can experience a drop in rectal temperature from 38°C–39°C to 34°C within the first hour of life (Pedersen et al., 2013; Conrad et al., 2022; Tucker et al., 2023), accompanied by reduced heart and respiratory rates. Physiological disturbances not only impair organ function but also decrease the piglet’s ability to metabolize energy efficiently, leading to weight loss and poor growth performance (Blavi et al., 2021).

Cold stress impairs piglet immune function. Hypothermic piglets absorb less colostrum, which contains the essential immunoglobulins needed for passive immunity. Lower colostrum intake reduces serum IgG levels, leaving piglets more vulnerable to infections such as scours, respiratory diseases, and systemic bacterial infections (Miguel et al., 2021). Cold-stressed piglets also have delayed leukocyte responses and lower disease resistance, which contributes to increased morbidity in the pre-weaning phase (Vande Pol et al., 2020). When exposed to cold, piglets respond behaviorally by huddling, shivering, and becoming more restless. Table 2 summarizes the effect of cold stress on piglet performance and behavior. Behaviors are energy-consuming and reflect the piglet’s attempt to conserve or generate heat. However, the energy diverted toward thermoregulation would otherwise be used for growth and immune development. Cold-exposed piglets may spend more time in high-risk areas, such as under the sow or in areas with high traffic, increasing their chances of injury or death (Lane et al., 2020; Ramirez et al., 2022). Maintaining appropriate thermal conditions in farrowing houses is critical for minimizing the negative impacts of low temperatures on piglet health, physiology, and behavior. Preventing cold stress through proper heating systems, microclimate design, and immediate postnatal care is crucial for enhancing piglet survival, reducing disease incidence, and promoting healthy growth. Table 2 summarizes the effect of cold stress on piglet performance and behavior. As indicated in Table 2, cold stress is harmful to piglet growth performance, welfare, and behavior. This underscores the importance of supplemental heating for piglets.

Effects of heat stress on piglet health, growth performance, and behavior

In farrowing environments, exposure to high ambient temperatures negatively impacts piglet health, growth performance, and welfare (Pedersen et al., 2015; Johnson and Stewart, 2025). When temperatures rise above the upper critical limit of the piglet’s thermoneutral zone, above 34°C for neonatal piglets and 28°C–30°C for older pre-weaned piglets, animals experience heat stress, triggering physiological and behavioral changes that compromise productivity (Gourdine et al., 2021). High temperatures impair growth traits, including average daily gain (ADG), body weight, and Feed conversion ratio (FCR) (Serviento et al., 2020; Dourmad et al., 2022). Heat-stressed piglets naturally reduce feed intake to minimize metabolic heat from digestion (Nguyen et al., 2023). Reduced feed intake, coupled with energy redirected from growth to thermoregulation, results in lower weight gain and higher FCR, reflecting decreased feed efficiency and increased production costs (Serviento et al., 2020; Wang et al., 2023).

Heat stress also induces distinct behavioral adaptations. Feeding behavior declines, with piglets reducing nursing and creep feed intake to avoid generating additional metabolic heat (Liu et al., 2022; Kazantseva et al., 2025). As a compensatory mechanism for fluid loss through respiration and evaporation, water intake increases (Gómez-Prado et al., 2022), highlighting the importance of providing easy access to clean water (Hoeck and Büscher, 2015; Brody, 2021; Liu et al., 2022; Vande Pol et al., 2022; Schale et al., 2023). Under heat stress, resting behavior is altered; piglets spread out, lie on cooler surfaces, and avoid contact to maximize heat dissipation (Lane, 2019; Zhu et al., 2020; Liu et al., 2022; Kazantseva et al., 2025; Kim et al., 2025). As thermoregulatory responses, they seek shaded, ventilated areas and exhibit increased panting or labored breathing (Liu et al., 2022; Chidgey, 2024; Kazantseva et al., 2025). Social interactions are also affected by increased aggression or competition for cooler spots in crowded or poorly ventilated environments (Renaudeau, 2020; Liu et al., 2022; Chidgey, 2024; Kazantseva et al., 2025). Activity and play behavior decline in extreme heat, and piglets often become lethargic and isolated to minimize internal heat production (Godyń et al., 2020; Liu et al., 2022; Kim et al., 2025).

Table 2. Effect of cold stress on piglet health, growth performance, and behavior.

Understanding these physiological and behavioral responses is essential for designing effective thermal management strategies, including environmental modifications, supplemental heating or cooling, and water and shade access. The effects of heat stress on piglet health, growth performance, and behavior are summarized in Table 3.

Table 3. Effect of heat stress on piglet health, growth performance, and behavior.

Mitigation strategies for heat stress in piglets

Heat stress is a major challenge in pig production, particularly during warmer seasons or in poorly ventilated farrowing environments. Therefore, effective mitigation strategies must be implemented to minimize its adverse impacts on piglets (Cottrell et al., 2015; Mayorga et al., 2019; Godyń et al., 2020; Kumar et al., 2025). Strategies often involve a combination of environmental modifications and nutritional adjustments aimed at improving thermal comfort and supporting physiological resilience during periods of elevated temperature (Justino et al., 2014; Cottrell et al., 2015; Perin et al., 2015; Godyń et al., 2020; Renaudeau, 2020; Blavi et al., 2021).

Environmental modifications, such as evaporative cooling pads, misters, and tunnel ventilation, to enhance air circulation and lower ambient temperatures, are particularly effective in tropical or subtropical regions where natural ventilation alone is insufficient (Mayorga et al., 2018; Mayorga et al., 2019; Liu et al., 2021). Air quality and ventilation are also vital elements of environmental management (Mayorga et al., 2019; Hu et al., 2023; Li et al., 2023; Khaowdang et al., 2025). Inadequate ventilation leads to heat accumulation and poor air quality, increasing the risk of respiratory infections and heat stress (Mayorga et al., 2019; Godyń et al., 2020; Brody, 2021; Ramirez et al., 2022; Hu et al., 2023; Li et al., 2023). Providing shaded areas, reflective roofing, and insulation in farrowing houses can help minimize heat build-up during the day (Machado et al., 2016; Malm, 2024; Lucas et al., 2025).

Installing flooring materials with good heat dissipation properties and separating sow and piglet thermal zones using barrier curtains also improves microclimate control for each age group (Godyń et al., 2020; de Oliveira et al., 2021; de Oliveira et al., 2024). Nutritional strategies designed to support piglet health and performance under heat stress conditions are also important and effective (Mayorga et al., 2018; Liu et al., 2021). Piglets typically reduce their feed intake during periods of high temperature, which can negatively affect their growth and immune response. However, to counteract this, dietary energy density can be increased using highly digestible fats and oils, allowing piglets to meet energy requirements without increasing feed volume (Liu et al., 2021). Supplementation with antioxidants such as vitamin C, vitamin E, selenium, and zinc improves cellular defense mechanisms and reduces high-temperature-induced oxidative stress (Gomes et al., 2025). Functional feed additives, such as electrolytes, probiotics, and betaine, also help maintain hydration, gut integrity, and metabolic balance during thermal stress (Sales, 2011; Mendoza et al., 2017; Singh et al., 2022; Lachica et al., 2024).

Water management is also an essential component of the mitigation of nutritional heat stress. Piglets exposed to heat stress have an increased need for cool, clean, and easily accessible drinking water. Ensuring that water is continuously available at appropriate temperatures not only supports hydration but also regulates body temperature and aids digestion (Schale et al., 2023). Continuous availability of water promotes regular intake, which facilitates digestion and nutrient absorption, ensuring efficient use of energy and minerals even under high-temperature settings (Shurson et al., 2021). Water at appropriate temperatures can help dissipate excess body heat, acting as a simple yet effective cooling mechanism that complements environmental and dietary interventions. Management practices such as proper placement of waterers, regular cleaning to prevent microbial contamination, and monitoring flow rates ensure that all piglets are healthy and grow well (Kumar et al., 2025).

Monitoring technologies in farrowing environments

The monitoring technologies in farrowing houses are tools and systems used to monitor the health, behavior, and environmental circumstances of sows and piglets. Their goal is to improve piglet welfare, productivity, and survival, especially during the critical newborn period when they are more susceptible to temperature stress, crushing, malnutrition, or sickness. These tools enable farm managers to identify problems early and take appropriate action to reduce losses and boost overall herd performance. The assessment of piglet welfare using thermal imaging involves the use of IR cameras to measure and display the surface temperatures of piglets, thereby preventing physical contact or distress (Kammersgaard et al., 2013; Gómez-Prado et al., 2022; Reza et al., 2024).

Using this technology, the natural IR radiation of the piglet’s body is detected and transformed into a thermal image, in which the temperature fluctuations throughout its skin are represented by distinct colors (Kammersgaard et al., 2013; Soerensen and Pedersen, 2015; Gómez-Prado et al., 2022). The health, comfort, and thermal welfare of a piglet can all be determined by thermal imaging (Vranken and Berckmans, 2017; Akinyemi et al., 2023; Reza et al., 2024) because temperature is directly related to physiological and environmental factors (Vranken and Berckmans, 2017; Govindasamy et al., 2022). Piglets benefit greatly from thermal imaging due to their inability to control their body temperature and susceptibility to hypothermia or heat stress. Piglets are in their thermoneutral zone, which is the range of temperatures where they are at ease and do not expend more energy to be warm or cool. Farmers and researchers can obtain temperature readings from key body parts, such as the ears, snout, and limbs. Thermal imaging can be used to detect fever, poor blood circulation, or cold stress without the need to handle the animal. The thermal imaging readings have a strong correlation with rectal temperatures, making it a viable non-invasive welfare evaluation method (Kammersgaard et al., 2013; Pardo et al., 2022; Stukelj et al., 2022; Tucker et al., 2023). The adoption of precision livestock farming technologies can enhance producers’ ability to maintain optimal environmental conditions in farrowing houses. Technologies enable the continuous monitoring of temperature, humidity, and air quality, allowing for real-time adjustments to ensure the welfare of both sows and piglets (Njenga et al., 2021; Papakonstantinou et al., 2024). The integration of smart sensors, automated controllers, and data management systems has become a cornerstone of modern pig production (Pandey et al., 2021; Burns and Spajić, 2024; Neethirajan, 2024; Marić et al., 2025), especially during the critical farrowing and lactation stages, when thermal and environmental stressors are highly sensitive to animals.

Environmental sensors are installed at various points within the farrowing unit to measure air temperature, relative humidity, floor temperature, CO₂ levels, and ammonia concentration (Wang et al., 2023). Sensors transmit real-time data to central control units or cloud-based platforms, enabling producers to detect deviations early and automatically adjust ventilation rates, heating elements, or cooling systems (Leliveld et al., 2024; Gassar and Jafar, 2025). The use of automated environmental monitoring improves piglets’ thermal comfort and reduces energy costs by maintaining consistent microclimates tailored to their developmental stage (Zheng et al., 2021; Kim et al., 2023; Burns and Spajić, 2024; Gassar and Jafar, 2025; Reza et al., 2025).

The ability of real-time data collection to prevent environmental extremes that can lead to health problems and increased mortality is important (McLennan and Mahmoud, 2019; Njenga et al., 2021; Papakonstantinou et al., 2024). Temperature drops in the creep area may expose newborn piglets to hypothermia, and humidity levels can increase the risk of respiratory infections (Kim et al., 2023). Continuous monitoring ensures that such risks are minimized by alerting farm personnel or triggering automatic system responses. Moreover, real-time data allow for the documentation and analysis of environmental trends, which can be used to optimize management decisions and improve overall farm performance (McLennan and Mahmoud, 2019; Njenga et al., 2021; Papakonstantinou et al., 2024).

Prospects and opportunities

Despite advances in optimizing farrowing environments, significant gaps remain in the understanding of individual variability in piglet thermoregulation, especially regarding hybrid, birth weight, and intrauterine growth restriction (Diehl et al., 2022). Future work should shift from generalized thermal recommendations toward precision phenotyping that links physiology, genotype, and behavior to adaptive microclimate requirements (Prates, 2025). Integrating precision livestock farming tools, such as IR thermography, wearable sensors, and Artificial intelligence-driven analytics, offers opportunities for real-time monitoring and predictive adjustment of temperature and airflow (Khaowdang et al., 2025), transforming thermal management from reactive to proactive control (Kammersgaard et al., 2013; Gómez-Prado et al., 2022; Akinyemi et al., 2023; Trabachini et al., 2025). Coupling these technologies with computational fluid dynamics modeling and digital twin simulations could enable genotype-specific, data-informed environmental design, while genomic and metabolomic insights may identify thermotolerant lines for selective breeding. Thus, the future of piglet climate control lies in the development of climate-smart farrowing systems that integrate animal physiology, engineering, and digital intelligence to enhance welfare, energy efficiency, and sustainability in intensive pig production (Pietrosemoli and Tang, 2020).

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Conclusion

Maintaining an optimal thermal environment in farrowing houses is fundamental to the survival, growth, and welfare of neonatal piglets. Because newborn piglets possess limited energy reserves and immature thermoregulatory capacity, even minor deviations from their thermoneutral zone can result in hypothermia or heat stress, compromising feed intake, immune function, and overall vitality. Effective thermal management requires an integrated approach that combines localized heating systems, precision ventilation, and data-driven microclimate control to sustain stable and comfortable environments. Recent advances in renewable energy integration, sensor-based environmental monitoring, and adaptive control algorithms offer new opportunities to enhance pig production efficiency while reducing the carbon footprint. Continued innovation in intelligent, energy-efficient heating technologies and climate-smart farrowing design will be pivotal for improving piglet welfare, reducing pre-weaning mortality, and ensuring resilient, sustainable productivity under changing climatic and production conditions.

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Acknowledgments

None.

Conflict of interest

The authors declare no conflicts of interest.

Funding

The APC was provided by the Tshwane University of Technology.

Author contributions

N. N. Nombuso: Conceptualization; methodology; validation; resources; writing—original draft preparation. Peter A. Idowu: Methodology; validation; resources; writing—review and editing. Khathutshelo A. Nephawe: Writing—review and editing; supervision. Takalani J. Mpofu: Conceptualization; methodology; validation; resources; writing—review and editing; supervision.

Data availability statement

All data were provided in the manuscript. No new data were created or analyzed in this study.

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