Agriculture Reference
In-Depth Information
bird will not show any signs of rhythmic breathing.
A return to rhythmic breathing in a stunned bird indi-
cates that it may be recovering from the stun.
Existing knowledge of mechanical stunning of
ostriches suggests that the tonic phase does not occur,
and stunning produces an extended period of up to
4 minutes of severe convulsions. Mechanical stunning
should only be used for emergency slaughter when elec-
trical stunning is not available.
At Grahamstown RSA, four operatives carry out the
stunning procedure: one guides the bird into the stun-
ning area, one holds the beak, one applies the electric
current, and the fourth rocks the bird backwards with
legs flexed into the body during the tonic phase, assisted
by the first operative from behind. This enables the
application of a leg clamp at the tarsometatarsal bone,
thus restraining the bird sufficiently to permit shackling.
At this point, the stunning tongs are removed, and the
fourth operative ring/chain shackles the bird via the big
toes and attaches the shackle to a chain hoist.
Extended application of the stunning current, for up
to 10 seconds, has been shown to delay the onset of kick-
ing (clonic phase), facilitate restraint of legs and reduce
the risk of injury during shackling and hoisting.
Bleeding must be carried out without delay after stun-
ning, and the cut must sever at least one of the carotid
arteries or the vessels from which they arise. The ostrich,
like other birds, has an asymmetric arrangement of
blood vessels in the neck, and bleeding should be
achieved by a complete ventral cut of the neck immedi-
ately below the head to sever both carotid arteries and
the jugular veins or by thoracic sticking to sever the
major blood vessels from which the carotid arteries
arise. Although bleeding from a high neck cut is initially
profuse, the total bleed-out time is prolonged, and birds
should be allowed to bleed for approximately 14 minutes
in a bleeding area before manual plucking takes place.
Restraint (Fig. 11.2)
Before stunning, animals must be restrained in an appro-
priate manner in order to ensure avoidable pain, suffering,
agitation or injury. Restraint is required to ensure that stun-
ning is carried out accurately and effectively; it does not
mean that the bird must be immobilised before stunning.
To assist in hoisting and shackling after stunning, birds
may be loosely hobbled at this point, although their legs
must not be tied in any way that may cause them to fall.
The birds should be brought up the raceway one at a
time. When the bird goes through the door, one opera-
tive, wearing rubber gloves, holds the beak or uses a
crook to bring the head down into a position easily
accessible to the stunning equipment.
Stunning
The electrodes should be designed and applied to ensure
maximum contact area with the head and must be cleaned
regularly to maintain optimum current flow. The use of
saline sponges in the stunning tongs may increase con-
tact area and current flow. The stunning tongs must span
the brain, either laterally (on either side of the head and
around the eyes) or vertically (to the top and bottom of
the head). If the birds are hooded during stunning, allow-
ance must be made for the possible effect of the hood
directing current away from the brain, especially if the
hood is wet. An application of 400 mA or greater, with
11 V for 2-6 seconds, causes insensibility for 60 seconds.
There will be a short phase of initial kicking after which
the bird will fall; it will be rigid with its legs flexed beneath
it, and the neck may arch over the back before falling for-
ward (the tonic phase). This is followed by kicking of
varied intensity (the clonic phase). An effectively stunned
Approach race
Operative 1
Dressing
The birds are then skinned, which should be done care-
fully to prevent dander contamination.
A longitudinal incision is made in the neck, the skin
is reflected, and the oesophagus is exposed and tied.
The neck is kept for edible purposes and placed at the
inspection point. Electronic identification devices must
be removed from the carcase at the time of slaughter to
prevent entry into the food chain.
The vent is freed from its attachments, tied and placed
in a plastic bag. Evisceration is performed by a mid-
abdominal incision above the breast plate. Ribs are cut
on both sides of the breast plate. Thoracic viscera are
exposed by pressing the breastplate down. The bagged
vent is pulled into the abdominal cavity, and the intestinal
Bird in optimum
stunning position
Leg clamp
Operative 3
Operative 2
Steel barrier
900 mm high
Operative 4
Figure 11.2
Stunning area and approach race (by kind permis-
sion of Dr Steve Wotton).
