Electrical stunning of cattle

Cattle are normally stunned electrically by three sequential cycles, first a three-second head-only cycle, to stun the animal, secondly a 15-second ca rdiac cycle, to induce ventricular fibrillation (cardiac arrest), and third ly a four-second discharge cycle, to reduce convulsions after death. An eff ective and immediate stun was produced when greater than or equal to1.15 am ps sinusoidal ne at 50 Hz was applied between the nose and neck electrodes for less than one second. However, when applied for three seconds, head-onl y currents of >0.46 amp sinusoidal Ac at 50 Hz were sufficient to induce ep ileptiform activity in the brain, identified as high amplitude low frequenc y activity in the electroencephalogram. The induction of effective head-onl y electrical stunning resulted in an average interval of 50 seconds before the return of rhythmic breathing movements, and positive corneal and palpeb ral reflexes. The cardiac arrest cycle successfully induced ventricular fib rillation when >1.51 amps sinusoidal Ac at 50 Hz was applied for five secon ds between the nose and brisket electrodes.