BEHAVIORAL AND HORMONAL RESPONSES OF PIGS DURING TRANSPORT - EFFECT OF MIXING AND DURATION OF JOURNEY

Two experiments investigated the welfare of pigs during transport. In experiment 1, 12 groups of four 90-kg pigs were transported to slaught er in a commercial livestock lorry for 1.5 h. Half the animals were tr ansported in their social groups (unmixed condition) and half were tra nsported with groups of previously unfamiliar pigs mixed together (mix ed condition). Behaviour was recorded, a general activity index scored and saliva samples taken at different stages of the journey for analy sis of cortisol. Pigs spent most of their time standing in both condit ions. The journey was very rough (as revealed by characterization with an accelerometer) and in the unmixed condition the pigs appeared to s tand to reduce travel sickness. In contrast, in the mixed condition, t his preference for standing seemed to be due to fighting which stresse d and exhausted the animals (the general activity index was three time s the unmixed condition). Levels of salivary cortisol were higher in t he mixed condition at the beginning, middle and end of the journey. In experiment 2, six 35-kg pigs, prepared in advance with jugular vein c atheters, were loaded onto a commercial livestock lorry (09.30 h) wher e they were individually penned. The vehicle remained stationary with the engine off and blood samples were taken at 30-min intervals during the next 8 h (control). Two days later this procedure was repeated wh ile the vehicle tons driven for 8 h (on main roads and motorways). Pla sma concentrations of cortisol and beta-endorphin increased markedly i n both conditions immediately after loading. Cortisol levels were grea ter (relative to control) at the beginning, in the middle and at the e nd of the journey. Concentrations of beta-endorphin did not differ bet ween control and experimental conditions except during the final 180 m in of the journey when the control levels were higher.