Water sprinkling market pigs in a stationary trailer. 1. Effects on pig behaviour, gastrointestinal tract temperature and trailer micro-climate

Pigs are often transported to slaughter under conditions outside their thermo-neutral zones, which can lead to reduced welfare and increased losses. Water sprinkling in barns is used to control microclimate resulting in pig body temperature reduction and improved welfare; however there is no clear evidence of these effects during transport. The aim of this study was to observe the effect of sprinkling pigs in trailers on behaviour and body temperature during transport and lairage, as well as to observe the effects on trailer microclimate e. In each of 12 weeks, 2 pot-belly trailers with 208 pigs each (n=4,992) were transported from the same farm on the same day 2 h to slaughter. One trailer was equipped with sprinklers that ran for 5 min ( 3c125 L) before departure and before unloading, the other trailer served as the control. In each trailer, 4 compartments were outfitted with cameras, ammonia detectors and temperature/humidity data loggers. The gastrointestinal tract temperature (GTT; \ub0C) of 4 randomly chosen pigs (n=384) in each test compartment was recorded using orally administered data loggers. Trailer and deck loading order were randomized. Behaviour during transport, unloading and lairage was recorded from video or live observations. Data were analyzed through ANOVA with ambient temperature external to the trailer (AmbT) as a covariate. AmbT averaged 19.5 \ub0C\ub13.8 \ub0C (range: 13.6 to 25.8 \ub0C). Sprinkled trailers showed lower (P=0.002) increases in internal compartment temperature from loading to unloading, smaller (P23 \ub0C, there was no effect of sprinkling on behaviour on the trailer, but at AmbT24 \ub0C (P=0.08). These data suggest that sprinkling pigs in a stationary vehicle when AmbT exceeds 23 \ub0C has the potential to prevent increases in body temperature during short duration transport without detrimental effects on ammonia levels or behaviour during unloading