The stability of social prominence and influence in a dynamic sow herd: A social network analysis approach

Abstract Social network analysis has developed as a valid technique in animal behaviour; despite an increase in the number of social network research in this field, comparatively few studies have focused on commercial animals. This study investigated a dry breeding sow herd (average = 69) as a model species for identifying socially prominent sows, individuals engaging in significantly higher levels of direct interactions than their conspecifics and socially influential sows, individuals with significantly higher levels of indirect interactions than their conspecifics. Animals were frequently added and removed from the herd during the study, creating a dynamic unstable social environment. In total, 63 h of video observations were obtained over three production cycles. Each production cycle covered 21 days, and behavioural observations occurred on days 1, 2, 3, 7, 14, 20, 21. The social network metrics of degree centrality (number of interactions), betweenness centrality (number of times an individual falls along the shortest path between two individuals) and centralisation (the extent to which a single individual dominates a network) were analysed to assess the stability of aggressive behaviour and preferential associations between production cycles. Preferential associations refer to lying behaviour