[Stress response of slaughter pigs in two different access systems to electrical stunning]

Investigations on two batches of 25 pigs each were carried out to characterize two different access systems for electrical stunning by physiological responses such as heart frequency (HF) and the blood constituents lactate and cortisol. All animals were of the same hybrid breeding program. The access race in system A, where the animals are separated was 11 m long. The personnel used different equipments including electrical rods to move the pigs forward. The lairage time after transport was between 1 to 2 h. In system B the animals arrived the evening before slaughter and spent the night in groups in straw-littered lairage boxes. The access race was 3.5 m long. The heart frequencies of the pigs in system A were between 80 and 240 beats/min, in system B the average HF were between 60 and 170 beats/min. In the lairage the HF were at about 113 beats/min (system A) and 66 beats/min (system B). Blood samples were taken immediately after stunning. The lactate concentrations differed by 6 mmol/l (8.6 mmol/l in system A, 2.6 mmol/l in system B). Cortisol was distinctly higher in the blood of the animals from system A (166 ng/ml) compared to system B (126 ng/ml). The results show that the used techniques are suitable to examine stress indicators of pigs under practical conditions. Access systems with long races seem to pose a higher stress than short access ways. The influence of handling (human factor) and management (size of groups, origin of pigs) is equally important. The role of longer resting times in the lairage should be investigated in more detail. This should also include the keeping conditions on the farm where the animals are raised.