Ham. Spoolder et al., INDIVIDUAL BEHAVIORAL-DIFFERENCES IN PIGS - INTRA-TEST AND INTER-TESTCONSISTENCY, Applied animal behaviour science, 49(2), 1996, pp. 185-198
Individual differences in behavioural responses are of increasing inte
rest in the behavioural sciences. There could be enormous benefits for
animal husbandry if a test could be developed that would identify cat
egories or types of individuals unlikely to cope with subsequent chall
enges. The present study compared the behavioural responses of two ser
ies of 16 groups (n = 6 or 7 gilts) under four different circumstances
: Situation 1, an open field with a novel stimulus (bucket or human);
Situation 2, individual access to food for 15 min after a 20-h period
of food deprivation; Situation 3, competition for food after food depr
ivation; Situation 4, general activity and feeding behaviour in a grou
p over a 24-h period. Situations 1 and 2 were assessed four and three
times over a 2- and 1-week period, respectively. Both showed high leve
ls of consistency in the behavioural responses of the gilts. Principal
component analyses were used to reduce the number of variables per te
st situation and facilitate measurement of consistency across test sit
uations. The amount of variation explained by the first component was
generally more than twice that explained by any subsequent components.
The only significant correlation between factor scores calculated fro
m the first components was found between Situations 1 and 2 in the fir
st series. None of the calculated factor scores showed bi- or multimod
al distributions. We conclude that, whilst over a short period of time
gilts respond consistently to a specific challenge, they do not displ
ay the same consistency when challenged in a different context. This l
ack of inter-situation correlations, plus the absence of multimodal di
stributions, fails to support the view that behavioural 'types' of gil
ts exist.