Jc. Talling et al., SOUND AVOIDANCE BY DOMESTIC PIGS DEPENDS UPON CHARACTERISTICS OF THE SIGNAL, Applied animal behaviour science, 58(3-4), 1998, pp. 255-266
Habituation to novel, loud and predictable sound stimuli appears to oc
cur in pigs, though this has not been unequivocally demonstrated. In a
ddition, different types of sound may be more or less aversive; humans
find unpredictable, intermittent sound more aversive than constant so
und. The aim of this study was to test these two hypothesis in pigs. T
wo groups of 12 pigs, weighing 25 kg, were individually exposed to a t
est sound in a modified unsignalled one-way avoidance procedure. The t
est sound for the first group was a recording from an animal transport
er played at 84 dB(Lin), with a rise time of 2 s (uniform, U). For the
second group, silent fragments, 59 dB(Lin), were randomly inserted in
to the recording, played at 86 dB(Lin), and the rise time was changed
to < 0.1 s (Intermittent, I). A total of 40 consecutive, 5 min tests w
ere carried out for each pig, 20 control and 20 with sound present. So
und present tests were arbitrarily split into three groups, comprised
of tests 1-6, 7-12 and 13-20, for analysis. Pigs did not significantly
avoid the uniform sound in any of the groups of tests, though they di
d increase their performance of active behaviour when the sound was fi
rst introduced (Control test no. 20, 15% of behaviour scans; Sound tes
t no, 1, 37% of behaviour scans; p < 0.01). The intermittent sound was
significantly avoided during all three sets of sound tests (Mean perc
entage of time spent avoiding sound area: Control tests 2-20, 35%; Sou
nd tests 1-6, 67%; Sound tests 7-12, 73%; Sound tests 13-20, 66%, p <
0.05). These pigs also showed significant increases in active behaviou
r during the first sound test (Control test no. 20, 14% of behaviour s
cans; Sound test no. 1, 42% of behaviour scans; p < 0.01), The results
suggest that aversion is dependent on characteristics of the sound, s
uch as uniformity, rather than neophobia, (C) 1998 Elsevier Science B.
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