Search

Fear induced by exposure to humans, and anxiety induced by novel environmental changes may both function as stressors and have negative effects on reproduction in pigs. An earlier experiment indicated that reactions to humans and novelty had some repeatability between the ages of 8 and 24 weeks, thus reflecting personality traits. The present experiment therefore tested for predicted negative relationships between behaviour related to fear and anxiety measured at 8 weeks of age and later reproduction in 30 sows. Factor analysis of behaviour in a voluntary human approach test performed in the home cage and a novel object test performed in a novel arena indicated that behavioural measures related to investigation of these stimuli loaded on separate factors and may therefore reflect independent underlying dimensions. One factor related to investigation of the human was interpreted as reflecting the level of fear of humans, while another was correlated to investigation of the novel object and interpreted as indicating novelty-induced anxiety. Factor scores were generated for ‘fear’ and ‘anxiety’ and used in regression analysis as predictors of maternal behaviour and reproductive parameters. Higher levels of fear of humans were associated with longer durations of farrowing, larger variation in inter-birth intervals, and a higher number of piglets dying without milk in their stomachs. The duration of farrowing was positively correlated to the number of live born piglets dying within 3 weeks of age. Higher fear also tended to associate with a higher number of stillborn and a higher number of live born piglets dying within 3 weeks of age. High anxiety only tended to be associated with a higher number of stillborn. These results are interpreted as supporting the hypothesis that there are negative associations between fear of humans and maternal ability in sows. [Copyright &y& Elsevier]

The coping styles hypothesis states that animals have consistent behavioural and physiological coping responses that can be characterised on a continuum from reactive to proactive. According to this hypothesis, animals can be characterised by consistency in responses across social and non-social situations as well as over time. We evaluated the validity of this hypothesis for predicting the coping responses of pigs by testing for predicted correlations between responses to a variety of challenges. Animals were exposed to an immobility test at 3 weeks of age. At 8 and 24 weeks, animals were exposed to an unknown pig in the test animal’s home cage, a human in the home cage, and a novel object (bucket) in a novel arena. None of the predicted correlations were found between the duration of immobility and behaviour in the later tests. Many behavioural measures had some repeatability between the ages of 8 and 24 weeks, despite significant changes in the observed level of responses, but there were few correlations between responses to social and non-social situations. Responses to a human and novel object were positively correlated when measured at 8 weeks but not at 24 weeks. The results indicate that the coping styles hypothesis has very limited value in predicting the coping responses of pigs representing the population as a whole. The existing correlations could more parsimoniously be described as reflecting responses to specific or closely related stimuli. It is suggested that future research on pig personality should investigate the possibility that specific coping behaviours—for example, those mediated by fear and anxiety—may have consequences for different elements of coping ability related to welfare and productivity. [Copyright &y& Elsevier]

The aim of the present experiment was to examine the effects of pre-test transport duration and animal age on the behaviour of 40 weaned pigs in a porcine elevated plus-maze (PEPM). The transport constituted of holding test animals together with pen mates in a transport trolley kept in motion by the experimenter. Multiple regression of behaviour on transport duration and animal age (between 33 and 54 days) indicated that longer duration of pre-test transport was associated with increases in the activity-related measure closed entries (CLE) in the PEPM, but was not associated with changes in the activity-related variable total entries (TE) or either of the anxiety-related behavioural elements percent open time (POT) or percent open entries (POE). Increasing animal age, on the other hand, was associated with decreases in both activity-related measures, but not with anxiety-related parameters. These results imply that animal age and the duration of transport prior to testing should be standardised across treatments in experiments in which evaluation of activity in this novel environment is important, but that measures related to PEPM anxiety are robust to the effects of variation in transport duration and animal age. [Copyright &y& Elsevier]