Factors Affecting the Transportation of Market-weight Pigs19 September 2013
Experiments in Canada reveal that pigs take longer to load into and double-decker trailers than pot-bellied trailers but the reverse occurs at unloading and there were differences in behaviour during lairage. Ramps and tight turns slowed the pigs' movement. Season affected the pigs slipping, falling and lairage resting behaviour.
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 behaviour, according to S. Torrey of Agriculture and Agri-Food Canada and others in two papers published in Journal of Animal Science. Other authors collaborating on the work represented the universities of Guelph, Manitoba, Saskatchewan and Laval (Quebec) and the Prairie Swine Centre - all in Canada.
Effect of Season, Truck Type and Location within Truck on Behaviour with a Two-hour Transport
The first experiment was designed to examine the influence of season and truck/trailer design on the behaviour during loading, transit, unloading and lairage of market-weight pigs transported to slaughter.
A total of 3,756 pigs were transported on either a three-deck pot-belly trailer (PB; n=181 pigs per week in eight experimental compartments) or a double-decker hydraulic truck (DD; n=85 pigs per week in four compartments) for two hours to a commercial abattoir in summer and winter (six weeks in each season). Density on both vehicles was 0.40 square metres per 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-degree turns, underlaps and vocalisations in winter than 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.
Torrey and co-authors concluded that vehicle design - in particular the presence of ramps - influenced pig behaviour before, during and after transportation, regardless of the season.
Season affected loading and unloading behaviour, 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 behaviour. Ramps and changes in direction during unloading appear to slow down the handling process.
Effect of Season and Location within Truck on Behaviour with an Eight-hour Transport
The second experiment by the same group of researchers examined the same parameters but for a longer trip of eight hours and only in a pot-belly truck.
A total of 1,170 pigs were transported (n=195 pigs per week in seven experimental compartments) for eight hours to a commercial abattoir in summer (six weeks) and winter (five weeks).
Pig behaviour was observed at loading, in transit, at unloading and in lairage. Handler intervention at loading was observed, and the time to load and unload was recorded.
Although season did not (P=0.91) affect loading time, more prods (P=0.014) were necessary to load pigs in summer than winter. Loading in winter also tended to be longer (P=0.071) into compartments involving internal ramps.
In transit, more pigs (P=0.025) were standing in winter than in summer.
Unloading took longer (P<0.006) in winter than in summer and from compartments where pigs had to negotiate ramps and 180-degree turns.
Furthermore, pigs in summer experienced more slipping (P=0.032), falling (P=0.004), overlapping (P< 0.001) and walking backward (P<0.001) than pigs in winter.
Pigs unloading from compartments with internal ramps slipped more (P<0.0001) than other pigs.
Season influenced latency to rest in lairage, with those transported in summer resting sooner (P<0.0001) than those in winter.
Torrey and co-authors conclusions following the second experiment were that season and location within trucks differentially affect pig behaviour before, during and after long-distance transportation.
They added that differences in lighting and temperature between seasons and the inclusion of internal ramps within vehicles may play important roles in the welfare of pigs transported to slaughter.
Torrey S., R. Bergeron, T. Widowski, N. Lewis, T. Crowe, J.A. Correa, J. Brown, H.W. Gonyou and L. Faucitano. 2013. Transportation of market-weight pigs: I. Effect of season, truck type, and location within truck on behavior with a two-hour transport. J. Anim. Sci. 91(6):2863-2871. doi: 10.2527/jas.2012-6005
Torrey S., R. Bergeron, L. Faucitano, T. Widowski, N. Lewis, T. Crowe, J.A. Correa, J. Brown, S. Hayne and H.W. Gonyou. 2013. Transportation of market-weight pigs: II. Effect of season and location within truck on behavior with an eight-hour transport. J. Anim. Sci. 91(6):2872-2878. doi: 10.2527/jas.2012-6006