EXPERIENCE IN SUBSTRATE-ENRICHED AND SUBSTRATE-IMPOVERISHED ENVIRONMENTS AFFECTS BEHAVIOR OF PIGS IN A T-MAZE TASK

Previous research showed that pigs reared in substrate-impoverished co nditions performed a smaller proportion of their total behavioural rep ertoire in their home pens (showed lower behavioural diversity), than pigs reared in substrate-enriched conditions. This study examined whet her these differences were the result of fundamental changes in behavi oural organisation. A T-maze task was used to test the hypothesis that substrate-impoverished pigs are prone to develop fixed, unvarying beh aviour which may underlie their reduced behavioural diversity. They we re predicted to be poorer at reversing previous response patterns in t he maze, and less able to alter their behaviour in response to a novel (distracting) stimulus. Female pigs were housed singly for five month s in substrate-impoverished pens with bare concrete floors (N = 10) or substrate-enriched pens with straw and other foraging material (N = 1 0). The pigs were then trained to negotiate a T-maze to reach a food s ource. There were no differences in responses to a distracting stimulu s in the start arm of the maze but, contrary to expectation, substrate -enriched pigs were less able to change their behaviour when the route to food was switched. Thus, the hypothesis was not supported. During training trials, substrate-enriched pigs moved fairly rapidly to the f ood while substrate-impoverished pigs spent more time investigating th e maze; their motivation to 'explore' the maze appeared to override th eir interest in food. The rapid, food-directed behaviour of the substr ate-enriched pigs probably became more fixed and routine-like than the more exploratory behaviour of the substrate-impoverished pigs. The ap parent importance of exploration to pigs reared in substrate-impoveris hed environments suggests that such conditions provide inadequate stim ulation.