Human-animal interactions during on-farm truck loading of finishing pigs for slaughter transport

Finishing pigs and transport drivers (TDs) interact closely when pigs are loaded for transport, which can be very stressful for both. We aimed to investigate relationships between TD handling actions and pig behaviours during loading for slaughter transport. In total 2,476 finishing pigs were loaded by 18 TDs (2 women, 16 men) during 18 loadings at 18 pig farms in Sweden over a 6 month period. Tactile, vocal and visual TD handling actions were recorded and characterized as 'moderately-strongly negative', 'mildly negative' or 'positive'. In the pigs, 'stress related', 'flow', 'disrupted flow' and 'relaxed' behaviours were recorded in all animals within 2 m in front of the TDs, using continuous video recordings, and summarized in 5-s intervals. Logistic models were constructed to estimate associations between actions and behaviours, including the preceding one or two intervals. The odds of stress related behaviour in the pigs was found to increase 5.4 and 4.1 times when a moderately-strongly negative and any negative TD action, respectively, occurred in the same interval. When a moderately-strongly negative and any negative TD action occurred in the preceding interval, the odds of stress related behaviour increased 2.0 times and 1.4 times, respectively. The odds of disrupted flow increased 1.6 times when any negative TD action occurred in the same interval. Furthermore, the odds of moderately-strongly negative TD action increased 5.4, 3.4 and 1.9 times, and the odds of any negative TD action increased 3.6, 2.9 and 2.1 times when stress related pig behaviour occurred in the same interval, the preceding interval and the interval before that, respectively. Pos-itive TD action in the same or preceding interval was associated with relaxed pig behaviour. This study suggests a reciprocal relationship between TD actions and pig behaviour, which provides an opportunity to improve TD actions through training in order to reduce stress behaviours in pigs.