INDIVIDUAL BEHAVIORAL-DIFFERENCES IN PIGS - INTRA-TEST AND INTER-TESTCONSISTENCY

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.