• To produce instantaneous unconsciousness, the bolt must penetrate the brain with a high concussive impact. For cattle, the stunner is placed on the middle of the forehead on an "X" formed between the eyes and the base of the horns. Some plants which save brains, place the stunner on the hollow behind the animal's poll on the back of the head. This position is less effective, therefore the frontal position on the forehead is recommended. Due to concerns about BSE (Bovine Spongiform Encephalopathy) saving brains is not recommended. Brain and spinal cord tissue should be discarded and not used as food for either people or animals.
  
  Cartridge fired captive bolt gun

• For sheep, a captive bolt is placed on the top of the head. This position is more effective for sheep because they have a very thick skull over the forehead. For pigs, the captive bolt is placed on the forehead.

• A good stunner operator learns not to chase the animal's head. Take the time and aim for one good shot. The stunner must be placed squarely on the animal's head. All equipment manufacturers' recommendations and instructions must be followed. Pneumatic stunners must have an adequate air supply. Low air pressure is one cause of poor stunning.
  
  Pneumatic captive bolt gun

• Poor maintenance of captive bolt stunners is a major cause of bad stunning. Pneumatic captive bolt stunners require cleaning and seal replacement every night in large plants. For example, a cattle plant which is double shifted and has a chain speed of 250 head per hour will require two to three pneumatic stunners to be completely serviced every night. It is important to keep stunner cartridges dry and the correct cartridge strength must be used.

• Eye reflexes should be checked often to insure that stunning is making the cattle unconscious. When the eyelid or cornea is touched there should be no response. An animal that blinks is not properly stunned. Breathing should have stopped and there should be no indication of a righting reflex when the animal is hanging on the rail. Reflexes may cause a stunned animal's legs to move, but the head should hang straight down and be limp.

Animal Welfare and Humane Slaughter

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