Differential effects of electrical stunning on the early post-mortem glycolysis in sheep

Electrical stunning methods have been examined to determine the effect on post-mortem glycolysis in various muscles of sheep. Although there was no effect on the ultimate pH achieved in any of the muscles, there were marked differences in the pH drop which occurred during stunning. When curare was used to block neuromuscular transmission much of the effect of stunning on glycolysis was removed. In the absence of neuromuscular blockage, head-only stunning produced the least drop in initial pH and the head-to-back and head-to-foreleg methods the greatest drop, especially in the anterior portions of the LD. Gash cutting without prior stunning produced marked drops in pH in most muscles. Prolonged (120s) head-to-back stunning gave more substantial drops in pH in the LD, BF, SM and ST muscles than did a shorter stun (1·4s). The prolonged stunning did not produce a change in rate of pH fall. Electrical stunning cannot be considered as a substitute for effective electrical stimulation as a means of hastening glycolysis to avoid cold shortening.