The effects of distance traveled during loading, lairage time prior to slaughter, and distance traveled to the stunning area on blood lactate concentration of pigs in a commercial packing plant1, 2, 3

A total of 144 market-weight swine were used to evaluate marketing stress: 1) distance traveled by pigs during loading at the production facility (LD; 15 m vs. 46 m), lairage duration at the slaughter plant (RST; 30 min vs. 240 min), and distance traveled by pigs to stunning (STN; 20 m vs. 300 m). Pigs were moved a short or long LD during loading and then transported 2.5 h to a commercial slaughter facility. Pigs were unloaded, rested for a short or long RST, and were then moved a short or long STN to the stunner. Pigs were electrically stunned and then exsanguinated. Blood lactate concentration ([LAC]) was measured in each individual pig at 7 sampling points during the marketing process: baseline, postload, preunload, prelairage, postlairage, postmovement, and at exsanguination. Blood lactate concentration changed (P < 0.0001) during the marketing process. Baseline [LAC] was 3.5 ± 0.2 mM. Long-LD pigs had greater (P = 0.0001) [LAC] postloading than did short-LD pigs (8.3 and 6.0 ± 0.4 mM). Long-RST pigs had greater (P ≤ 0.02) [LAC] than short-RST pigs postlairage, postmovement, and at exsanguination. Blood lactate concentration was greater (P < 0.02) in pigs moved a short STN as compared with a long STN (7.2 and 6.0 ± 0.2 mM). Blood lactate concentration responds to alterations in preslaughter swine management procedures at the production and the packing facility.