3. Results
The effects of the stimuli on general behaviour are summarised in Tables 2 and 3. In Trial 1, pigs were generally attracted by the visual stimuli, which reduced turning away
Table 4 Effect of stimulus presentation on change in mean approachravoidance distance from the food box in Trial 1.
Ž .
Mean values have been adjusted for the covariate approachravoidance distance before stimulus presentation Ž .
Stimulus Change in mean distance m
Variance Visual stimuli
0.37 0.32
Funnel 0.46
0.18 Umbrella
0.53 0.47
Torch light y0.04
0.23 Mirror
0.69 0.22
Rod 0.23
0.18 Olfactory stimuli
0.13 0.12
Eucalyptus oil 0.23
0.11 Triethylamine
0.12 0.15
Vanillin 0.29
0.11 Oil of wintergreen
y0.03 0.19
Mineral turpentine 0.08
0.06 Aniseed oil
0.09 0.15
Auditory stimuli y0.19
0.20 Piglet squeal
y0.48 0.10
Bell bird song y0.18
0.19 Buzzer
y0.18 0.21
Sow grunt y0.27
0.31 Cap gun
0.08 0.30
Smoke alarm y0.12
0.10 Tactile stimuli
0.05 0.23
Slap 0.08
0.25 Prod
0.19 0.41
Rub 0.10
0.27 Clip
y0.20 0.10
Water 0.00
0.14 Brush
0.16 0.25
Complex stimuli 0.15
0.25 Toy robot
y0.18 0.36
Standing human 0.35
0.19 Sitting human
0.08 0.36
Sitting human with maskrgloves 0.28
0.10 Green food
0.19 0.09
Control stimuli 0.02
0.20 Control empty
y0.08 0.27
Control food 0.12
0.09 SED
0.132
from the stimulus, elimination, and elicited short latencies to eat and enter the stimulus box.
Olfactory stimuli had virtually no impact on behaviour. Auditory stimuli tended to increase turning behaviour and resulted in the longest latencies to eat and enter the
Table 5 Effect of stimulus presentation on change in mean approachravoidance distance from the food box in Trial 2.
Ž .
Mean values have been adjusted for the covariate approachravoidance distance before stimulus presentation Ž .
Stimulus Change in mean distance m
Variance Visual stimuli
y0.13 0.21
Dropping ball 0.08
0.15 Standing cross
y0.23 0.06
Flashing light y0.04
0.18 Revolving cross
y0.51 0.11
Moving tail 0.05
0.34 Olfactory stimuli
0.13 0.15
Glacial acetic acid 0.20
0.11 Almond oil
0.22 0.22
Ethanedithiol 0.01
0.23 Skatole
0.14 0.17
Amyl acetate 0.14
0.06 Citronella oil
0.05 0.13
Auditory stimuli y0.26
0.12 Dog bark
y0.32 0.13
Pig bark y0.26
0.06 White noise
y0.42 0.16
Siren y0.30
0.20 Compressed air
y0.18 0.05
Vibrating steel y0.05
0.07 Tactile stimuli
y0.04 0.17
Feather duster 0.19
0.24 Aerosol spray
y0.02 0.11
Hot air y0.28
0.19 Control air
y0.17 0.07
Electric prod 0.04
0.22 Control prod
0.01 0.12
Complex stimuli 0.00
0.31 Rabbit
0.12 0.44
Toy dog y0.27
0.39 Quinine food
y0.03 0.29
Sitting human 0.13
0.12 Blue food
0.06 0.23
Control stimuli y0.04
0.09 Control empty
0.06 0.11
Control food y0.14
0.06 SED
0.147
Table 6 P-values for within stimulus-type effects
Trial Stimulus type Variable Turns away Eliminations Latency to eat Latency to stimulus Approachravoid distance
1 Visual
0.12 0.42
0.76 0.36
0.00 Olfactory
0.43 0.96
0.90 0.89
0.20 Auditory
0.64 0.62
0.63 0.04
0.00 Tactile
0.31 0.91
0.58 0.40
0.04 Complex
0.47 0.07
0.55 0.04
0.00 2
Visual 0.05
0.16 0.00
0.09 0.00
Olfactory 0.37
0.61 0.90
0.54 0.70
Auditory 0.03
0.68 0.43
0.20 0.20
Tactile 0.98
0.18 0.72
0.04 0.03
Complex 0.60
0.32 0.12
0.36 0.05
stimulus box. Tactile and complex stimuli had similar effects as auditory stimuli, but tended to reduce rather than increase turning behaviour. In Trial 2, some of the visual
and auditory stimuli appeared to have marked aversive effects with long latencies to eat Ž
. and enter the stimulus box. Several stimuli the revolving cross, pig bark, and siren had
latencies to enter the stimulus box greater than 100 s, which is approaching the maximum limit of 120 s.
The effects of the stimuli on approachravoidance behaviour are summarized in Tables 4 and 5. In Trial 1, visual, olfactory and complex stimuli had a positive effect on
behaviour, whereas auditory stimuli had a negative effect. Tactile and control stimuli were neutral. The most aversive stimuli were the piglet squeal and the sow grunt. The
most attractive stimuli were the mirror, umbrella, funnel and standing human. In Trial 2, visual and auditory stimuli had a negative effect, with olfactory, tactile and complex
stimuli mostly neutral. The most aversive stimuli were the revolving cross, white noise, dog bark and siren. The most attractive were almond oil, glacial acetic acid, and the
feather duster.
The power of the five dependent variables to detect significant differences between stimuli in the five sensory groups is shown in Table 6. There were no significant
differences in elimination, two in turning behaviour, one in latency to eat, and three in latency to enter the stimulus box. In contrast, seven significant differences in
Table 7 Ž
. Pearson product-moment correlations between the five variables for pooled data ns60 stimuli from two
trials. Probability values are given in brackets Eliminations
Latency to eat Latency to stimulus
Approachravoid distance Ž
. Ž
. Ž
. Ž
. Turns
0.045 0.73 y0.381 0.00
y0.249 0.06 y0.223 0.09
Ž .
Ž .
Ž .
Eliminations 0.084 0.52
0.164 0.21 y0.197 0.13
Ž .
Ž .
Latency to eat 0.797 0.00
y0.496 0.00 Ž
. Latency to stimulus
y0.544 0.00
approachravoidance distance were detected. There were significant differences between Ž
. Ž
individual pigs blocks in nine of the 10 anovas comprising Table 6 not elimination, .
Trial 2 . Ž
. Correlations between the five variables Table 7 showed a negative association
between approachravoidance distance and the other four variables. The correlation was significant for latency to eat and latency to enter the stimulus box. There was also a
significant negative association between latency to eat and turning behaviour, and a significant positive association between latency to eat and latency to enter the stimulus
box. Elimination was not significantly associated with the other variables.
4. Discussion
Kategori