blocked on replicate. Although it is recognised that the treatments were not applied at random due to practical constraints, this was not included in the statistical analysis.
3. Results
3.1. Experiment 1 The average times to enter the CO crate on the day of treatment are presented in
2
Table 1. Only pigs that met the training criteria during the training sessions on days 1 and 2 were included in the experiment. In the first replicate, 11 of 15 pigs were trained,
with three pigs assigned to the control treatment, four pigs to the CO treatment and four
2
pigs to the prodder treatment. In the second replicate all pigs were trained, with five pigs Ž
assigned to each treatment. After two training sessions on day 3, treatments control, .
Ž .
90 CO or prodder were applied during the next session labelled session 0 . Because
2
treatment was applied after the pigs entered the CO crate, the times during session 0
2
would not have been affected by treatment. While there was no treatment effect during Ž
. Ž .
session 1 P 0.05 , time to re enter was significantly greater in the prodder than the Ž
control treatment in sessions 2, 3, 4 and 5 P - 0.05, P - 0.01, P - 0.001 and
. Ž
. P - 0.05, respectively . There were no P 0.05 differences between the CO and the
2
Ž . control treatments. Time to re enter was significantly greater in the prodder than the
Ž .
CO treatment in sessions 4, 6 and 7 P - 0.05 .
2
3.2. Experiment 2 The average times to enter the CO crate on the day of treatment during experiment 2
2
are presented in Table 2. In the first replicate, 12 of 15 pigs were trained, with four pigs
Table 1 Ž .
Ž . Experiment 1: Average times s to re enter stunning unit on the day of treatment, with treatment applied
during session 0 Ž
. Control
90 CO Electric prodder
LSD P -0.05
2
Session 0 23.6
23.9 23.6
3.12 Session 1
22.0 27.0
25.9 7.18
a b
Session 2 21.4
25.8 32.9
8.14
p q
Session 3 18.2
22.8 28.6
6.01
x a
y,b
Session 4 18.8
22.3 34.7
8.24
a b
Session 5 18.4
23.1 31.8
11.33
a a
b
Session 6 18.5
20.3 31.9
8.68
a a
b
Session 7 18.2
18.8 30.6
9.62
a,b
P -0.05.
p,q
P -0.01.
x,y
P -0.001.
Table 2 Ž .
Ž . Experiment 2: Average times s to re enter stunning unit on the day of treatment, with treatment applied
during session 0 Ž
. Control
60 CO Electric prodder
LSD P -0.05
2
Session 0 30.6
30.2 27.0
8.59 Session 1
31.9 37.3
46.3 23.39
Session 2 31.6
37.2 50.7
19.72
a a
b
Session 3 32.2
24.4 55.9
19.07
a a
b
Session 4 28.4
26.6 48.4
16.76 Session 5
24.8 21.1
34.9 13.69
Session 6 23.5
22.0 28.4
11.30 Session 7
26.7 20.3
30.9 12.91
a,b
P -0.05.
per treatment. In the second replicate, all 15 pigs were trained, with five pigs per Ž
. treatment. Treatments were applied on day 3 session 0 after two training sessions. No
Ž . differences were found between treatments in time to re enter the crate during session 1
Ž .
Ž .
P 0.05 . However, there were significant P - 0.05 differences between the control treatment and the electrical prodder during sessions 3 and 4. There were no significant
Ž .
P 0.05 differences between the CO and the control treatments during any of the
2
sessions. 3.3. Experiment 3
There is some indication that the CO crate may be slightly more aversive than the
2
V-restrainer belt when the pigs are first presented to these stunning units. The average Ž
. times to enter both stunning units CO crate and V-restrainer belt for the first time on
2
Ž .
the first training day were 38.6 and 22.0 s, respectively P - 0.05 . The difference
between the two units disappeared after training. The average times to enter the stunning units on the day of treatment are presented in
Table 3. In the first replicate 12 of 14 pigs were trained, with six pigs per treatment. In the second replicate, all 14 pigs were trained with seven pigs per treatment. Treatment
on day 3 was applied during session 0. Descent in the crate or transport through the
Table 3 Ž .
Ž . Experiment 3: Average times s to re enter the stunning unit on the day of treatment, with treatment applied
during session 0 Ž
. CO crate
V-restrainer LSD P -0.05
2
Session 0 17.9
19.3 3.16
Session 1 18.4
17.4 2.51
Session 2 18.4
16.4 2.31
Session 3 18.4
16.8 2.25
Session 4 18.3
16.7 2.22
Ž . V-belt restrainer in operation did not significantly change the time to re enter either
Ž .
stunning unit P 0.05 .
4. Discussion
