Searching for differences in the behavioural response of piglet groups subjected to novel situations.

The Backtest (BT), the Open Field (OF) and the Novel Object (NO) tests have been used to identify individual reaction patterns in piglets and to measure parameters that previous studies have shown to be correlated to the coping strategies of animals. The BT allows for the classification of piglets into two different "coping styles": high-resisting (HR) and low-resisting (LR), which respectively correspond to a (pro-)active and passive (or reactive) behavioural response. During previous research, the subjects were tested singularly, so the aim of this study was to investigate if differences between HR and LR animals could be detected when piglets are tested in a group using the OP and NO tests. A total of 132 piglets were subjected to the BT and then were housed in groups consisting of four individuals each so as to obtain HR pens, LR pens and mixed pens. We found differences in the pigs' behaviour during the OF and the NO tests and according to the type of group. Individual differences in the behavioural response of piglets to the Backtest were not predictive of the behavioural response of the animals subjected to the OF or to NO tests. Our results show that there are no relevant differences between HR and LR piglets when they are subjected in a group to novel situations.