Captive bolt gun t i stunning

Captive bolt gun
stunning
Bo Algers
Swedish University of Agricultural Sciences

I wish to acknowledge
my PhD student Sophie Atkinson who
did most of the studies presented here.

The placement of the weapon on cattle:

Placement of the weapon, sheep and goat without horns:
Placement, sheep and goat with horns:
OBS! Shorter stun-to-stick:
15 sek!

Stun should cause immediate unconsciousness

Background
• The Swedish regulation requires sticking
within 60 seconds after stun (cattle & pigs).
• Industry wanted extensions of this time;
(If stun quality was good – could stun to
stick intervals be extended)
- development of stun quality audits.

Objectives
• Monitor the stun to stick intervals times
• Assess the stun quality
- 100 bulls & 100 other cattle classes
(per audit)

shooter
Stunbox
Stun crate
Stun effect observation
Back leg shackling
2 m
2 m
3 m
3 m
sticking
sticking
Stun to stick was timed
- Started when shot was heard
- Stopped when knife thrust into throat

Results
Stun to stick intervals
• 5% of the cattle were stuck within 60
seconds

Stun Quality
Good stun
Poor Stun
Undefined
Symptoms
- dilated pupils
- no eyeball rotation
ti
- no corneal reflex
- minimal reaction to sticking
- corneal reflex
- spontaneous blinking
- breathing/respirations
- fixed eyeball rotation ti to stick
- gasping, groaning
- excessive struggling at stick
(with no other symptoms)

Stun quality results cattle
% Poor stuns
Abattoir Cows Bulls Both
1( (c) 36 3.6 15 10
Uneven edge on bolt
1 (c) 3 15 7.2
1(c) 13 1.3 13 63 6.3
2 (c) 0 28 16.6
2(p) 0.3 1.7 0.6
3 (c) 0.7 16.3 6.7
4 (c) 0 13 4
5 (c) 1.3 5.8 3.7
Total 1.4%
A
13.5%
6.8%
(n= 1552) n=1250 (n = 2802)
Damp amunition
Pnuematic stunner
c= captive bolt
p = pneumatic stunner

Pneumatic bolt stunner

E
B
A
C
D

%of animal class showing poor stun symptoms shot in skull area A
Bulls
91% Cow s
8%
Steers
1%
* Total amount showing poor stun 10%

Percent of each cattle class reshot
Pe ercentage e
20
18
16
14
12
10
8
6
4
2
0
97/585
20/306
3/58
4/49
Bulls Cows Steers Calves
Animal class

Percent of cattle class with poor stun quality all audits
%
16
14
12
10
8
6
4
2
0
13,6
1,4
Bulls
(n=1250)
cows,heifers,strs,calves
, ,
(n=1552)

Conclusions
This audit system provided a valuable tool
for assessing & improving
welfare of animals at slaughter
Stunning large cattle with a captive bolt gun
may result in a large proportion of animals not
being properly stun.

Stun quality in relation to cattle size,
gun type and brain haemorrhages

Objectives:
Examine, in depth, the causes behind poor stun
quality in cattle, especially large animals.
594 cattle in two abattoirs (A and B) were observed
by assessing stun quality. 14 of those were examined
macroscopically for brain haemorrhages.

A captive gun bolt (abattoir A and B) and a pneumatic bolt (B)
were used.
The firing velocity and energy values were for the 0.22
calibre gun bolt:
Black cartridges - 66.8 m/s and 517 joules
Rd Red cartridges tid - 56.4 m/s and 361 joules
Specifications for the pneumatic bolt were;
Operating pressure 11-12 bar
Air consumption per cycle
41 L
Penetrating bolt diameter 15.9 mm

: Displayed signs grouped and rated from 1 - 4
Rating
1
2
3
Signs displayed
•Corneal reflex
•Spontaneous blinking
•Full or partial eyeball rotation up to sticking
•Full or partial eye ball rotation followed by pupil
dilation i before sticking
4 •Gasping, groaning
•Excessive struggling or kicking at sticking

Frequency of signs rated 1 or 2 in abattoir A
and B.
Abattoir Gun type Sign ratings 1& 2
Cows
(n=400)
Bulls
(n=194)
A Gun Bolt 30% 3.0% 15.0%
B Gun Bolt 0.0% 28.0%
B Pneumatic Bolt 0.3% 1.7%

Effect of bolt velocity and diameter of a captive bolt gun on energy transfer (joule),
To the animal´s head and the presence of Visual‐Evoked Responses in the brain
(Gregory and Shaw, 2000)
Bolt velocity (m/sec ‐1 )
47 55
Bolt diameter Energy VER Energy VER
(mm) transfer transfer
12 97+17 3/6 124+25 1/8
14 125+18 2/8 139+25 1/8
16 158+20 1/7 186+30 0/7
VER´ s were measured as an index of brain function
by way of electrocorticograms taken from electrodes planted into the
brains of the cattle. The electrical wave values given indicate the brains
ability to respond to external stimulus, which in this case were light
flashes from a source 1 meter in front of the animal’s eyes.

Phineas Gage (1823-1860), railroad
construction foreman in Vermont, USA,
got 1848 this rod through his head,
survived but had severe changes in
his personality.
After a couple of minutes he
was able to talk and then
walk to a carriage in which
he in sitting position traveled
a few kilometers to get medical
assistance.

Brain damage on captive bolt shot bull showing
signs of good stunning.

Blood haemorrhages in the range of 25-50% after
Blood haemorrhages in the range of 25 50% after
captive bolt stunning with poor stun quality.

E
B
A
C
D
Recommended area, A,
for placing the bolt
in a 90 degree angel.

Cartridge bolt shot bull
shot 3 times.
Pneumatic bolt shot bull
shot once.

Bleeding in brain cavity of a bull
shot with captive bolt and which
showed signs of poor stunning.
Bleeding in brain cavity of a bull
shot with a captive bolt and which
showed signs of good stunning.

: Displayed signs grouped and rated from 1 - 4
Rating
1
2
3
Signs displayed
•Corneal reflex
•Spontaneous blinking
•Full or partial eyeball rotation up to sticking
•Full or partial eye ball rotation followed by pupil
dilation i before sticking
4 •Gasping, groaning
•Excessive struggling or kicking at sticking

Reflex symptoms & related brain bleedings damage around level the brain stem
11
. cattle
No
10
9
8
7
6
5
reflex rate 0
Reflex rate 4
Reflex rate 3
Reflex rate 2
Reflex rate 1
4
3
2
1
0
Major brain
stem bleedings
Minor brain
stem bleedings

Normal shot
angle
Shot angle that t would optimize i damages
to brain stem area
The brain damages seen by the pneumatic bolt tended to be larger,
with more and heavier bleeding areas at the back of the brain.
This suggests that the brain is shaken more vigorously with the
pneumatic bolt at shooting, contributing to higher stun quality.
Bleedings on the brain as a result of a hit, tend to occur on the
opposite part of the brain where the impact occurred (“contre-coup”
-effect).
To create a rapid and massive bleeding it is favourable to cause an
arterial bleeding in the subdural or subarachnoidal areas around the
brain stem and basal parts of the brain.

Conclusions:
Heavy blood haemorrhage or even brain matter disintegration
in the frontal regions of the brain, does not necessarily indicate
certain unconsciousness or insensitivity to pain.
However, if there are arterial bleedings around the brain stem,
even if small, and subarachnoid haemorrhaging at the base
of the brain, there will be definite, rapidly commencing
state of unconsciousness and a high probability of death.

45
CNR
40
PSCR
35
PSR
% Anim als
30
25
20
15
CNR
CNR
CNR
10
5
0
PSCR
PSR
PSCR
PSR
PSCR
PSR
Bulls
Cows, steers,
calves
All cattle
Cattle category

Conclusions:
A penetrating bolt stunner should have enough power,
but further investigations are needed to assess which is
the proper direction of the bolt gun, in particular in large
animals, in order to obtain arterial bleedings around the
brain stem and at the base of the brain.

I don´t want to
hear no more!!