Familiarity and personality affect social support in juvenile pigs in a foam stunning situation

Abstract: Animals in distress can experience an attenuation of their stress response if provided companionship. This thesis studied the social support phenomenon in 72 nine-week old juvenile pigs (Sus scrofa domesticus) of the crossbreed Yorkshire/Hampshire. Pigs were placed either alone or with a familiar or an unfamiliar age-matched conspecific of the opposite sex in a stunning box. Half of the groups were exposed to an air-filled foam inside of the box and the other half was exposed to an empty box. All pigs underwent an individual behaviour assessment at eight-weeks of age for a personality evaluation. The results of this thesis indicate that pigs were startled by the foam exposure as suggested by changes in activity, escape attempts and vocalisations. Indications of social buffering were found with regards to performance of escape attempts, altered activity patterns and engagement in affiliative social behaviours. Differences were observed in the social behaviour of familiar and unfamiliar pig pairs, suggesting that familiarity between pigs should be preferred from a welfare perspective. Correlations between possible personality traits and the pigs’ behaviour in the foam box study can be understood within the coping style framework. The results suggest that pigs show variation in their need for social support and that personality could have been a bias in interpreting the pigs’ behavioural response to the foam stunning situation. This thesis provide support that the welfare of pigs during foam stunning may be improved if pigs are stunned in groups of familiar individuals.