Transportation of market-weight pigs: I. effect of season, truck type, and location within truck on behavior with a two-hour transport.

There is evidence that season and truck/trailer design play important roles in pig welfare during transportation although little is known about their interaction and effect on pig behavior. This experiment was designed to examine the influence of season and truck/trailer design on the behavior during loading, transit, unloading, and lairage of market-weight pigs transported to slaughter. A total of 3,756 pigs were transported on either a 3-deck pot-belly trailer (PB; n = 181 pigs/wk in 8 experimental compartments) or a double-decker hydraulic truck (DD; n = 85 pigs/wk in 4 compartments) for 2 h to a commercial abattoir in summer and winter (6 wk in each season). Density on both vehicles was 0.40 m(2)/pig. Accounting for the number of pigs, loading took longer (P = 0.033) onto the DD than the PB, but season did not (P = 0.571) influence loading time. Pigs loaded onto the PB moved backward more (P = 0.003) frequently than those loaded onto the DD. The frequency of tapping by handler was the lone handling intervention affected by truck type, with more (P = 0.014) tapping needed to move pigs on and off DD than PB. During loading, pigs made more (P < 0.001) slips and falls, overlaps, 180° turns, underlaps, and vocalizations in winter compared with summer. On truck, more (P < 0.001) pigs were standing on the DD at the farm and in transit than on the PB whereas more (P = 0.012) pigs were lying in transit in summer than in winter. Pigs took longer to unload (P < 0.001) from the PB than the DD, but no difference between vehicles (P = 0.473) in latency to rest in lairage was found. Pigs slipped and fell more (P < 0.001) during unloading, took longer (P < 0.001) to unload, and had a shorter (P = 0.006) latency to rest in lairage in winter than summer. Vehicle design, in particular the presence of ramps, influenced pig behavior before, during, and after transportation, regardless of the season. Season affected loading and unloading behavior, especially in terms of slips and falls on the ramp, and differences in truck/trailer designs were also partly to blame for unloading times and lairage behavior. Ramps and changes in direction during unloading appear to slow down the handling process.