Humane-Slaughter-Guidelines

7. When head-only stunning is used, equipment
should be designed so that the animals are bled
within 15 seconds after stunning. Well-designed
commercial plants that perform religious slaughter
with head-only stunning have equipment that
is capable of achieving this goal. The two main
methods for achieving rapid bleeding are either
high-speed hoists or bleeding the animal on a table
immediately after it is ejected from the stun box or
restrainer.
8. The electrodes must be kept clean. A wire brush
should be used to clean the electrodes several times
each day.
9. Stunning tongs or wands should be ergonomically
designed to reduce operator fatigue.
10. Rotate the operators to help prevent fatigue. Data
collected from an electronically monitored stunning
unit showed that after 3 hours, the operator
was more likely to fail to firmly press the electrode
against the animal. Firm contact is essential for an
effective stun. 130
11. Both sides of a V conveyor restrainer should run
at the same speed. If one side runs faster than the
other, the animals will become agitated.
12. Use insulated restraint equipment. Plastic slats are
recommended on V conveyor restrainers, and there
should be no exposed bolts. When single-animal
restrainers are used, they should be insulated with
plastic meat cutting board.
13. For operator safety, all electric stunners should be
equipped with an isolation transformer or other
device that will prevent electricity from flowing
from a single electrode to ground. The electricity
should only flow between the two electrodes. The
metal frame of the restrainer and operator catwalk
must be connected to a good ground.
14. All electric components such as the stunner switch,
plugs, cords, and control box should be kept dry.
The only part of the stunner that should be wetted
is the electrodes. When the plant is cleaned,
the stunning tongs or wand should be removed and
stored in a dry location. The stunner control box
should be either placed in a separate dry room or
kept covered during plant wash down.
15. Several types of restrainers (for head and body)
can be employed for a variety of species. Cattle,
for example, must have a properly designed head
restraint. A head holding device is usually not required
for pigs or sheep.
16. Employee training is essential.
T2.3 Other Physical Methods
T2.3.1 Decapitation
Decapitation is not commonly employed in the
commercial slaughter of food animals, but is often used
for on-the-farm slaughter, primarily of poultry and rabbits.
137 When properly employed, this technique can be
a quick and humane method of slaughter, but if done
incorrectly, it has the potential to induce pain and distress
on the animals. This method may be found to be
aesthetically displeasing to those performing or observing
the technique.
In poultry killed by decapitation, convulsions frequently
occur immediately to several seconds following
application of the technique. Postmortem convulsions
were minimized when chickens were electrically
stunned prior to decapitation. 143
Decapitation without prior stunning is rarely used
in poultry slaughter plants. 121 Decapitation is also a
method that is sometimes used for home slaughter of
poultry. 137 Early studies 144–146 on the effects of decapitation
on brain electric activity in chickens, sheep, and
rats showed persistence of activity for up to 13 to 14
seconds following decapitation, resulting in the conclusion
that the animals’ heads remained conscious during
this time and may have experienced pain. However,
many recent studies 147–150 have shown that this activity
does not imply the ability to perceive pain, and they
conclude that loss of consciousness occurs rapidly following
decapitation. The concern that the blow from
the decapitating device might induce pain is mitigated
by the fact that afferent sensory nerves for the head and
neck enter the spinal cord at the level of the second cervical
vertebrae in most species; therefore, the severing
of the spinal cord at or above that level would prevent
sensory input from the tissue injury from reaching the
brain. 150
Operator competence is required to perform decapitation
in a humane fashion. The operator must
be familiar with the technique and able to accurately
place the blade high on the neck, ideally at the level
of the first vertebra. Blades used for decapitation must
be maintained to be kept sharp and able to sever the
entire head without need for more than one blow. Animals
must be restrained to prevent them from moving
away from the blade. For poultry, restraint in a bleeding
cone will not only facilitate accurate aim, but will
also minimize tissue trauma from postmortem convulsions.
Electrically stunning a bird prior to decapitation
reduces the occurrence of postmortem convulsions. 143
T2.3.2 Cervical dislocation
Cervical dislocation is not commonly employed in
the commercial slaughter of food animals, but is often
used for on-the-farm slaughter, primarily of poultry
and rabbits, 151 therefore the Panel has opted to provide
guidance.
For poultry, the legs of the bird should be grasped
(or wings if grasped at the base) and the neck stretched
by pulling on the head while applying a ventrodorsal
rotational force to the skull. Crushing of cervical
vertebrae and spinal cord is not acceptable unless the
bird is first rendered unconscious. Personnel should be
trained on anesthetized or dead animals to demonstrate
proficiency.
Data suggest that electrical activity in the brain
persists for 13 seconds following cervical dislocation
in rats, 148 and unlike decapitation, rapid exsanguination
does not contribute to loss of consciousness. 149,150
For some classes of poultry, there is evidence that
cervical dislocation may not cause immediate
unconsciousness. 145,152–154
Cervical dislocation is a method that may induce
rapid loss of consciousness, 148,155 does not chemically
contaminate tissue, and can be rapidly accomplished.
However, cervical dislocation may be aesthetically
AVMA Guidelines for the Humane Slaughter of Animals: 2016 Edition 39