2.3. Behavioural observations
Behaviour of the pigs was recorded on 2 days within
the same week when the pigs were an average of 13 and
20 weeks of age (approx. 40 and 90 kg live weight,
respectively). The number of pigs in each pen assuming
the postures and performing the behavioural elements
described in Table 1 were recorded at 15 min intervals
(instantaneous recording) during 1 h before allocation
of rooting material (starting at 09.00 h), during 1 h
after allocation of rooting material (starting at 10.00 h),
and during 1 h in the afternoon (starting at 13.00 h).
The behavioural elements ‘root pig’, ‘chew tail’, ‘chew
ear’ and ‘nose pig’ were combined to one element
‘manipulate pig’. Due to practical problems with
allocation of rooting material the observation at 13
weeks of age was not conducted for the 12
pens in building one. Thus the data included for building
one were 12 pens1 age2 days3 h and for
building two 24 pens 2 ages 2 days 3 h; i.e. a total
of 360 h of observation. For each hour of observation
there were four recordings, and the mean percentage of pigs performing any of the behavioural elements per
hour was calculated and used as input in the statistical
analyses.