Behavioral responses of group-housed pigs are strongly influenced by pigsty environmental conditions, yet their dynamic coupling is difficult to quantify under commercial farming scenarios. This difficulty arises from high inter-pig similarity, complex interactions, and rapidly changing environmental conditions, which pose significant challenges for existing vision-based multi-pig behavior detection and tracking methods. To address these challenges, this study proposes a PIG-Net–based dynamic coupling analysis framework that integrates behavior detection, multi-pig tracking, and behavior-environment interaction analysis. The model uses an EfficientRepBiFusion backbone with bidirectional feature fusion and a lightweight LSDGCD detection head, achieving mean Average Precision (mAP) of 93.5% for PIG YOLO on four pig behaviors—standing, dog-sitting, lateral lying, and prone lying. The integrated PIG-Net system achieves stable tracking performance with identification average rate (IDF1) of 90.7%, multiple object tracking accuracy (MOTA) of 88.6%, and a real-time processing speed of 26 FPS, while environmental sensors continuously record temperature, humidity, and CO₂ levels for long-term correlation analysis. Based on long-term monitoring, Pearson correlation analysis was applied to quantify the associations between pig behaviors and environmental factors, highlighting significant correlations with coefficients |r| ranging from 0.65 to 0.76. By combining these quantitative results with temporal and dimensionality reduction analyses, temperature, humidity, and CO₂ were identified as the primary environmental drivers. Active behaviors decreased under elevated temperature and humidity and increased during cooler and drier periods, whereas prone lying and lateral lying increased under thermal and moisture stress. Elevated CO₂ concentrations further suppressed activity, reflecting inhibitory effects of degraded air quality. These findings provide a quantitative basis for behavior-environment coupling assessment and early health warning in group-housed pigs.

Dairy production zone is often located in the cold regions, such as the northeastern provinces of China. Seasonal calving patterns are predominantly adopted in these cold regions. Calf production has concentrated in winter rather than summer, in order to reduce the negative impact of the heat on the mature cows' milk production. However, the calves can be subjected to severe cold stress during the colder months. The feeding practices during the calf stage can also dominate the adult milk production, thereby contributing 10%–20% of potential milk yield. Compared with the adult dairy cows, the calves exhibit the significantly lower environmental tolerance, due to the underdeveloped thermoregulatory capabilities. It is then required for the optimal architecture and environment of the calf barns. The prevailing low-temperature and high-humidity in winter barns can readily induce the calf diseases, such as diarrhea and respiratory infections, leading to the high morbidity and mortality rates. Alternatively, the retrofitting existing structures can be expected for the energy efficiency level. Before that, the heat load can be predicted to assess the heating energy demand, and standard energy savings rate. Among them, the thermal resistance and insulation performance of the envelope can significantly influence the effectiveness of the heating systems. Existing conventional calf barns generally exhibit inadequate thermal insulation in their envelope structures. Supplemental heating is also required to fully meet the environmental requirements for the calves in winter. It is very urgent to predict the heat load of the calf barns, in order to better understand the energy consumption under specific temperature and the minimum thermal resistance. Precise regulation can also reduce the carbon emissions in modern agriculture. This study aims to predict the winter heat load of the calf barns in the cold regions under dual carbon context. Case subjects were also selected as the representative cities in Northeast provinces of China. According to the energy-mass balance equation and heat exchange, a mathematical model was developed to predict the thermal loads in the cold-region calf barns. Thermal resistance of the building envelopes was firstly optimized to consider the latent heat production from the dairy cows, indoor heating thermal loads, heat loss through envelope structures and ground heat transfer, ventilation heat loss, and air infiltration heat loss. The minimum thermal resistance was recommended for the envelopes of the calf barns in different regions. Furthermore, a one-month validation trial of the thermal load model was conducted at a dairy farm in Ranghulu District, Daqing City, Heilongjiang Province, China, from January 24 to February 24, 2025. The temperature and humidity were then recorded both inside and outside the barn. The information parameters were then measured on the envelope structures of the calf barns. The results revealed that there was a high incidence of calf diarrhea and respiratory diseases in the experimental calf barn, with a mortality rate reaching 16%. Particularly, a large-scale pneumonia outbreak was observed in the barn in December 2025. Therefore, the environmental factors were the critical determinants of the calf health and production efficiency. The high accuracy of the prediction was achieved in a relative error of only 2.4% between theoretical heat load and actual heat dissipation. The minimum thermal resistance was recommended in the range from 0.81 to 1.91 m²·°C/W and 1.01 to 2.39 m²·°C/W, respectively, for the calf barn walls and roofs. There was the significant influence of the indoor humidity on the requirements of the minimum thermal resistance for the winter envelope structures in various cities. Once the relative humidity increased from 50% to 80% at the indoor temperatures of 12°C, the thermal resistance of the Harbin's calf barn south wall raised from 0.41 to 1.23 m²·°C/W—an increase exceeding 200%. Furthermore, the thermal load and carbon emission performance were compared across three building envelope scenarios (model barn, conventional barn, and enhanced barn). A 5 000-head dairy farm calf barn was selected in Harbin City, Heilongjiang Province, China. According to the minimum thermal resistance of the building envelope, the model of the calf barn was predicted to save 154 420 kWh of electricity per month, compared with the conventional barn. This value was translated to approximately 6 930 Yuan in electricity cost savings and a reduction of 8 480 kg of CO₂ emissions, indicating the significant potential to the energy conservation and carbon reduction. The social cost of carbon was incorporated with the economic and environmental benefits. The barn model was further enhanced the prediction, in terms of economic and sustainable environment. Overall, the minimum thermal resistance was determined for the winter heat load for the calf barns in Northeast China. The finding can provide the theoretical references to improve the calf rearing environments in the cold regions, in order to advance the energy conservation and emission reduction in calf barns.

The establishment of biosafety system is of enormous importance to the livestock and poultry production in terms of mitigating the transmission of diseases and implementing regional prevention and control measures. However, the current sterilization technology presents several drawbacks, including time-consuming procedures, chemical residues, and challenges in treating the sewage after rinsing. In this study, a novel cleaning and sterilization method that combines slightly acidic electrolyzed water and high pressure water-jet was developed. An orthogonal test was conducted to examine the correlation between high-pressure conditions and the various non-structural parameters on the efficacy of sterilization rate. In a field test, the effectiveness of the technology in cleaning pig transfer vehicles was evaluated by the total plate count and variations of community composition. The findings revealed that the combination of process parameters, including an available chlorine concentration of 200 mg/L, rinsing pressure of 170 bar, rinsing duration of 10 s, and residence time of 15 min, resulted in a removal rate of colony concentration on the surface of pig transfer vehicles of (96.50±0.91)%. Moreover, it was demonstrated to effectively inhibit a variety of pathogenic bacteria. The innovative cleaning system has the potential to replace traditional methods and reduces pollution while saving time and labor. It introduces a novel approach for sterilization of transportation in livestock and poultry farms as well as the biosafety construction of the animal husbandry.