Effects of Stocking Density in the Pen and Lairage Time on Blood Stress Indicators, Skin Lesion Scores, and Pork Meat Quality

The objective of this study was to assess the effects of stocking density in the pen and lairage time before slaughter on blood stress indicators, skin lesions, and pork meat quality traits. A total of 1920 immunocastrated male pigs were shipped to a slaughterhouse. In order to maintain the proposed stocking densities, 72 pigs out of the 1920 animals were removed across loads from the experiment. The remaining 1848 pigs were randomly assigned to two different stocking densities in the lairage pen (0.42 m²/100 kg and 0.66 m²/100 kg) and two lairage times (2 h and 6 h). A total of 360 pigs were selected for the analysis of exsanguination blood glucose, creatine kinase, lactate dehydrogenase, cortisol concentration, hematocrit percentage, and carcass skin lesion scores, whereas meat quality was assessed in 240 loin muscles. Except for blood hematocrit percentage, the interaction stocking density × lairage pen had no effect on any parameter (<i>p</i> > 0.10). When compared to a lower stocking density (0.66 m²/100 kg), pigs kept at a higher stocking density (0.42 m²/100 kg) tended to present lower blood LDH concentrations (<i>p</i> = 0.06) and higher blood cortisol concentrations (<i>p</i> = 0.08) at slaughter and had greater carcass skin lesion scores (<i>p</i> < 0.001) and drier (lower drip loss) loin muscles (<i>p</i> = 0.04). Increased blood hematocrit percentage was found in pigs kept in lairage at a higher stocking density for 6 h when compared with the other lairage conditions (<i>p</i> < 0.01). Overall, stocking density, in particular when it was high, influenced more pigs' stress conditions at slaughter and carcass and meat quality than the time spent in lairage.