|Title||(Em)pathetic pigs? : the impact of social interactions on welfare, health and productivity|
|Source||Wageningen University. Promotor(en): Bas Kemp, co-promotor(en): Liesbeth Bolhuis; Bas Rodenburg. - Wageningen : Wageningen University - ISBN 9789461739964 - 264|
|Publication type||Dissertation, internally prepared|
|Keyword(s)||varkens - sociaal gedrag - sociaal milieu - emoties - diergedrag - dierenwelzijn - diergezondheid - fokwaarde - dierlijke productie - varkenshouderij - pigs - social behaviour - social environment - emotions - animal behaviour - animal welfare - animal health - breeding value - animal production - pig farming|
|Categories||Pigs / Animal Behaviour and Ethology|
The welfare, health and productivity of intensively raised pigs may be affected by routine management procedures and the physical environment they are housed in, but also by their social environment, i.e. by social interactions between pen mates. In this thesis, the effect of social interactions on pig welfare, health and productivity has been investigated in several ways. On the one hand, a new breeding method based on interactions, i.e. on heritable effects on the performance of pen mates, was investigated. The effect of divergent selection for a relatively positive or negative indirect genetic effect on growth of pen mates on pig behavior and physiology was studied. On the other hand, it was investigated whether pigs can be affected by (the emotional state of) their pen mates on the basis of two social processes, emotional contagion and social support. Pigs selected for a relatively positive indirect genetic effect on the growth of their pen mates seemed less fearful and less stressed in several novelty tests and they had lower leukocyte, lymphocyte and haptoglobin concentrations compared to pigs selected for a relatively negative indirect genetic effect on the growth of their pen mates. Moreover, it was found that pigs can indeed be affected by the emotional state of their pen mates either in a positive or negative way, which points to emotional contagion, a simple form of empathy, in pigs. Furthermore, evidence for social support has also been found. To conclude, this breeding method may be a strategy to improve the social environment of intensively raised pigs as pigs with relatively positive indirect genetic effects for growth may create a less stressful social environment for themselves. In addition, the welfare, health and productivity of pigs may not only depend on their own emotional state, but also on the emotional state of their pen mates.