Spatial learning in pigs: effects of environmental enrichment and individual characteristics on behaviour and performance

Abstract

This study investigated the eVects of both environmental enrichment and individual behavioural characteristics on spatial cognitive capabilities of pigs, using a novel latent spatial learning paradigm based on Tolman's detour experiments (1948). Pigs were housed either in 'barren' pens or in pens enriched with straw bedding from birth. Pigs were restrained in a Backtest at 10 and 17 days postpartum. Based on their escape behaviour in this test, which has been shown to reXect their behavioural style, six 'high-resisting'(HR) and six 'low-resisting' (LR) pigs were selected from each housing environment (n = 24 in total). At 12 weeks of age, pairs of pen mates (LR and HR) were exposed to a maze three times (exploration trials). Pigs were then placed individually in the maze, and social reinstatement proved to be a strong incentive to Wnd the exit leading to the home pen. We subsequently blocked the direct route to the exit, forcing animals to Wnd a detour (memory test 1, MT1). This test was repeated once to investigate the relative improvement, i.e. detour learning (memory test 2, MT2). Housing condition and Backtest response strongly aVected exploration patterns. In spite of this, no eVects on performance during the subsequent memory tests were found. Performance was substantially improved in MT2, indicating that once a goal is apparent, pigs are able to solve a complex spatial memory task easily. In conclusion, social reinstatement provided a good incentive to complete a spatial task, and the substantial improvement in performance between MT1 and MT2 stresses the need for task complexity when testing spatial memory in pigs. Housing conditions or individual behavioural style did not aVect spatial memory during MT1 or MT2. However, housing environment and behavioural style strongly aVected explorative behaviour of pigs in an unfamiliar maze during both exploration trials and memory tests. This implicates that apparent eVects of environmental enrichment on spatial learning and memory in pigs might reXect diVerences in explorative patterns rather than in cognitive processes.

Tail Biting in Pigs: Blood Serotonin and Fearfulness as Pieces of the Puzzle?

“…Another personality trait that may contribute to the tendency of animals to develop aberrant behaviours is fearfulness or anxiety [19], [20] which may be reflected in the response to novel situations [21], [22]. Additionally, in pigs the behaviour in novelty tests has been associated with coping styles [23], tail biting [20], and serotonergic blood and brain parameters [22]. Therefore, the main aim of our study was to explore whether tail biting in pigs, in a longitudinal study, is associated with behavioural and physiological responses to challenges, and also with blood serotonin.…”

Nurturing brain plasticity: impact of environmental enrichment

“…[24][25][26][27] Although EE research has been mostly focused on rodents, similar effects have been reported in several species of mammals (gerbils, ground squirrels, rabbits, cats and primates). [28][29][30][31][32] …”

Geography, Science, and Subjectivity: Farm Animal Welfare in the United States and Europe

“…2008). And perhaps not surprisingly, researchers have concluded that pigs are good problem‐solvers (Wood‐Gush and Vestergaard 1991; Jansen et al. 2009).…”