Stunning is a mandatory step for the slaughter of animals in slaughterhouses. It refers to any process that causes immediate loss of consciousness and suppresses the animal’s perception of pain, which lasts until the animal’s death. Employees responsible for stunning are certified and capable of performing and recognizing effective stunning. A second stunning system must be available in the event of a malfunction of the first system (eg: equipment failure, or poor efficiency of the stunning).
Mandatory animal restraint
To facilitate stunning, immobilization of animals is mandatory. It prevents any pain, fear or agitation of animals, protects employees and allows them to ensure good stunning. The operator will find it easier to use the equipment properly if the animal is calm and immobilized in the slaughter box. To limit the stress of the animal, the immobilization should be of short duration and the slaughter should be done without undue delay.
In general, the materials and equipment used for restraint and stunning are suitable for the species and the sizes of the animals.
Checking the animal’s unconsciousness after stunning
Once stunning, the operator checks the animal’s unconsciousness.
The main signs of unconsciousness in animals to observe are:
- the immediate collapse,
- the absence of oriented head movements,
- the absence of a corneal reflex (absence of movements of the eye and eyelids after touching the cornea)
- the absence of vocalization,
- the absence of a respiratory rhythm,
- eyes fixed and motionless.
If all of these signs are observed, then the animal does not present a risk of regaining consciousness. If there is any doubt about a sign, the operator should immediately re-stun the animal to minimize pain.
Warning: Certain reflex movements of the animal, which are a muscular and nervous response to a stimuli, do not correspond to signs of consciousness. This is the case, for example, with the pedaling of the visible legs, in particular during the evacuation of the immobilization system and when the animals are hung by the hind legs.
After stunning, the animal is lifted by the hind leg, in order to accelerate the loss of blood following the bleeding (or section of the blood vessels) of the animal which must be carried out as soon as possible after the stunning, in order to that the animal empties its blood without pain. After bleeding, the operator must verify the death of the animal before continuing any operation on the line (especially the so-called “dressing” phase or removing the leather).