Effects of Slaughter Date, On-Farm Handling, Transport Stocking Density, and Time in Lairage on Digestive Tract Temperature, Serum Cortisol Concentrations, and Pork Lean Quality of Market Hogs1

The objective of this study was to evaluate the effect of on-farm handling intensity (conventional vs. passive), transport stocking density: (high vs. low), and preslaughter lairage time (45 min vs. 3 h) on digestive tract temperature, serum cortisol concentrations, and pork quality of market pigs slaughtered in November (NOV; n = 111), February (FEB; n = 113), and August (AUG; n = 112). Pigs slaughtered in FEB had greater (P ≤ 0.027) digestive tract temperatures before loadout than pigs slaughtered in NOV or AUG. The digestive tract temperature of pigs slaughtered in AUG was greater (P ≤ 0.027) during than before loadout. Pigs afforded 3 h of lairage tended to have greater (P = 0.068) digestive tract temperatures than pigs given 45 min of lairage. When pigs were slaughtered in AUG and NOV, those afforded 3 h of lairage had greater (P = 0.042) cortisol concentrations than pigs given only 45 min of lairage. Carcasses of pigs slaughtered in AUG had a paler (P ≤ 0.032) LM than carcasses of pigs slaughtered in NOV and FEB, and greater (P ≤ 0.032) LM purge losses than pigs slaughtered in FEB. Pigs given a 45 min lairage had greater (P = 0.036) 30-h LM pH values, darker LM (P = 0.008), greater (P = 0.012) subjective color scores, and tended (P = 0.069) to have lower purge loss percentages than pigs given a 3-h lairage. Results indicated that pigs should have less than 3 h of lairage when the day\s low ambient temperature is ≤ 22°C to decrease antemortem stress and improve lean quality.