Pig slaughtering procedures: Head-to-back stunning

High voltage head-to-back electrical stunning can induce vertebral compression fractures, blood splash and poor meat quality in pigs. This experiment was designed to determine the optimum position of the rear electrode which would not only stun and kill pork and bacon weight pigs with a 1·3 A 50 Hz sinewave but would also produce a good carcass with desirable meat quality. Although there was a trend for less breaks to occur the further forward the rear electrode was positioned, there was no position which gave 100% cardiac fibrillation and an absence of breaks. The incidence of blood splash, muscle haemorrhages and the variations in meat colour were not related to electrode position and fell in the ‘normal’ range quoted by other workers. The severity and incidence of kicking after stunning was reduced the more caudal the electrode position. This was in direct contrast to the effect on compression fractures where a reduction was seen with the more rostral applications.