In both captive bolt and electrically stunned animals kicking will occur. Ignore the kicking and look at the head. To put it simply, THE HEAD MUST BE DEAD. When cattle are shot with a captive bolt, it is normal to have a spasm for 5 to 15 seconds. After the animal is rolled out of the box or hung up its eyes should relax and be wide open. After electrical stunning, a properly stunned animal should have a rigid (tonic) phase followed by a clonic (paddling of the legs) phase. This is an indication of a grand mal epileptic seizure. The seizure induces insensibility. Very long application of the current may weaken or eliminate these reactions in a properly stunned animal.

Below are the signs of a properly stunned animal:

  1. The legs may kick, but the head and neck must be loose and floppy like a rag. After captive bolt or electrical stunning, a normal spasm may cause some neck flexing, but the neck should relax and the head should flop within about 20 seconds. Check for natural blinking that looks like a live animal in the yards if flexing continues. Animals stunned with gas stunning equipment should be limp and floppy though they may exhibit slow limb movement.
  2. The tongue should hang out and be straight and limp. A stiff curled tongue is a sign of possible return to sensibility. If the tongue goes in and out, this may be a sign of partial sensibility.
  3. When cattle and pigs are hung on the rail, its head should hang straight down and the back must be straight. In sheep, the head should be limp and floppy but due to anatomical differences, the neck may be on an angle. It must NOT have an arched back righting reflex. When a partially sensible animal is hung on the rail it will attempt to lift up its head. It will be stiff. Momentary flopping of the head is not a righting reflex. Compared to cattle and pigs, sheep necks may not hang completely straight due to differences in anatomy.
  4. When captive bolt is used the eyes should be wide open with a blank stare. There must be no eye movements. Immediately after electrical stunning the animal will clamp its eyes shut, but they should relax into a blank stare. It is normal for animals stunned properly with electricity to have nystagmus (vibrating eye).
  5. When captive bolt is used the animal must NEVER blink or have corneal reflex in response to touch. In electrically stunned pigs eye movements can be misinterpreted when untrained people indiscriminantly poke at the eyes. It is often best to observe without touching the eye. If a pig blinks with a natural blink where the eye closes and then re-opens it is not properly stunned. If you are not sure what a natural blink looks like, go and look at live pigs in the yards (lairage) before assessing insensibility. Natural blinking must be absent after all stunning methods.
  6. Rhythmic breathing must be absent after ALL stunning methods. Count as rhythmic breathing if the animal’s ribcage moves two or more times. Gasping is a sign of a dying brain and is acceptable after gas or electric stunning. It will look like a fish out of water. A twitching nose (like a rabbit) may be a sign of partial sensibility. Gasping must be absent after captive bolt.
  7. In captive bolt stunned animals, insensibility may be questionable if the eyes are rolled back or they are vibrating (nystagmus). Nystagmus is permissible in electrically stunned animals, especially those stunned with frequencies higher than 50 or 60 cycles. Nystagmus must not be confused with natural blinking.
  8. Shortly after being hung on the rail, the tail should relax and hang down.
  9. No response to a nose pinch or pinprick on the nose. The painful stimulus should be applied only to the nose. Animals entering a scauld tub must not make a movement that is in direct response to contact with the hot water. For all types of stunning this is an indicator of possible return to sensibility.
  10. No vocalization (moo, bellow or squeal) after all methods of stunning.

The above methods can be used for determining insensibility for all types of stunning and for ritual slaughter which is done without stunning. Just remember, kicking reflexes are normal in captive bolt stunned animals, electrically stunned animals and after ritual slaughter. They should be absent or very feeble for C02. Captive bolt stunning induces instant insensibility by both concussion and physical destruction of the brain. Stunner maintenance is essential to maintain maximum hitting power.