Electrical stunning methods used commercially on pigs are effective and induce instantaneous insensibility. Insufficient amperage or a current path that fails to go through the brain will be painful for the animal. It will feel a large electric shock or heart attack symptoms, even though it may be paralyzed and unable to move. When electric stunning is done correctly, the animal will feel nothing. There are two types of electric stunning, head only and cardiac arrest stunning, which stops the heart.
Most large plants use cardiac arrest head to back or head to side of body stunning.
It produces a still carcass that is safer and easier to bleed. Cardiac arrest stunning requires the use of a restraining device to prevent the animal from falling away from the stunning wand before it receives the complete stun. Cardiac arrest stunning kills the animal by electrocution. Head only stunning is reversible. Pigs which are stunned with a head only stunner must be bled within a maximum interval of 30 seconds to prevent them from regaining consciousness.