Cognitive enrichment affects behavioural reactivity in domestic pigs

Abstract

Cognitive challenges presented in connexion with the foraging behaviour of animals may have the potential to enrich the housing environment of captive animals, and thus can have beneficial effects on their behaviour and welfare. Therefore, we have developed a food-rewarded learning system based on a combination of classical and operant conditioning for groups of domestic pigs using acoustic cues (‘call-feeding station’). The present study investigated the characteristics of learning behaviour in seven experimental groups ( n = 8 individuals each) of growing pigs in postnatal weeks 7–20. The behavioural budget of each group was observed weekly within the housing environment and compared to seven conventionally fed control groups ( n = 8) which were supplied with an equal food amount. The alterations of individual behavioural responses after 6 and 12 weeks of cognitive enrichment were analysed in combined open-field/novel-object tests and compared to controls. All experimental pigs were able to discriminate reliably an individual tone that was associated with a locally changing feeding site. Generally, the animals were also willing to work for food (push a button with increasing fixed ratio, FR) but this motivation varied considerably between the groups ranging from FR 1 to 10. Sustained cognitive enrichment also affected other behavioural patterns within the housing environment as indicated by an increased locomotor behaviour and less belly nosing. Behavioural test responses were altered towards a greater reduction in open-field activity as well as a reduced excitement and fear behaviour compared to control pigs. Behavioural differences seem to be more pronounced the longer pigs were faced with the cognitive challenge. However, with equal food intake, the weight gain of the experimental pigs was not different compared to the controls. The present study suggests that, in domestic pigs, the presented cognitive enrichment may induce repeated positive appraisals in pigs by the association of successful coping with a demanding behavioural task rewarded by several small portions of food during the day. This appears to agree very well with pigs’ motivational needs and may also be applicable for animal welfare enhancing management of feeding.