Q2E on head only stunning of sows

In short the answer is:

In case the electrical parameters are sufficient to induce immediate unconsciousness during head only electrical stunning, an exposure duration of 1-5 seconds is considered to be long enough to guarantee that unconsciousness remains long enough to apply proper bleeding, taking into account that the sticking is performed immediately or shortly after ending the electrical application. In this case, longer exposure times than the minimum required duration will not result in pain or discomfort.

Head only stunning induces an epileptiform seizure, which will result in tonic immobility during and after the exposure of the current which will be followed by a clonic phase some seconds after ending the application of the current. In case of long exposure duration (in this case 14 s) to an electrical current, leading into a long tonic phase, it will be possible that the clonic phase will no longer occur after ending the application. Instead of the clonic phase the pigs will show low muscle tone. In that case tonic-clonic seizure is not an applicable Animal Based Indicator (ABI) for unconsciousness or effective stunning. Other ABI’s that are advised are absence of (rhythmic) breathing, cornea and palpebral reflex, muscle tone and righting reflex. While absence of these ABI’s is indicating effective stunning after the end of the stunning procedure, long current durations carry the risk of masking delayed or, in the case of induced cardiac fibrillation, absent induction of epileptiform seizures during the stunning procedure, which could be a cause of pain or discomfort.

Introphoto: Head-only electrical stunning (©IRTA)