PERSONALITY, COPING PATTERNS AND AGGRESSION IN PIGLETS

To search for a pattern of behaviour similar to the one found for active and passive coping strategies in rodents, we tested piglets in a series of different tests. One of the tests was a restraint test previously used by Hessing et al. (1993a,b). In this test the piglet was turned on its back and held there for 1 min while the number of escape attempts was counted. This first test was done on 65 piglets (males and females, 2 weeks of age). In our study the result of the bad-test was unimodal, not bimodal as suggested by Hessing et al. (1993a,b). The back-test was then repeated over time on another group of piglets (once a week; all piglets female, n = 45, 1-5 weeks old). In addition, a number of other tests were done (8-10 weeks). These were tests designed to measure parameters that previous studies have shown to be correlated to the coping strategies of the animals: namely, extinction time, social dependence, reaction to a novel object, and aggression in an owner/intruder conflict. We did not find any correlation between the latency to attack acid the parameters measured and thus found no evidence for the existence of active/passive copers in domestic pigs. A principal component analysis (that explained 60% of the total variation) suggested three personality traits: aggression (25%), sociability (20%) and exploration (15%).