Effects of Preslaughter Lairage Duration and Environmental Temperature on Physiological Stress, Behavior, and Meat Quality in Finishing Pigs

This study investigated the interactive effects of lairage duration and environmental temperature on physiological stress responses, behavioral patterns, and meat quality characteristics in finishing pigs. A total of 1,809 crossbred pigs (Duroc × [Yorkshire × Landrace]) weighing 115-120 kg were subjected to two lairage durations (0-4 h vs. 4-8 h) under three environmental temperatures: low temperature (LT, <10°C), normal temperature (NT, 10-24°C), and high temperature (HT, >24°C). Results demonstrated that environmental temperature significantly affected cortisol concentrations (p<0.001), with LT conditions producing elevated stress responses compared to NT and HT treatments. Lairage duration influenced lactate accumulation patterns, indicating differential energy metabolism dynamics across temporal treatments. Interactive effects between temperature and duration were observed for multiple parameters including pH values (p<0.001), glucose concentrations (p=0.036). Water-holding capacity showed significant temperature-dependent variations (p<0.001), while meat color yellowness was significantly affected by thermal conditions (p<0.001), and lightness was significantly affected by lairage duration (p<0.01). Behavioral observations revealed that HT exposed pigs exhibited increased lying behavior and reduced standing time compared to other groups, reflecting thermoregulatory adaptations. Aggressive behaviors and overlap activities were significantly affected by environmental temperature (p<0.001), with HT pigs showing markedly reduced frequencies compared to LT and NT pigs. The incidence of quality defects, particularly PSE characteristics, numerically increased under HT conditions. These findings demonstrate that optimal lairage management requires integrated consideration of both temporal and thermal factors rather than addressing these variables independently. The results emphasize the need for flexible, context-specific protocols that account for environmental conditions and their interactions to maintain animal welfare and product quality under varying commercial conditions.