Leadership linked to group composition in Highland cattle ( Bos taurus ): Implications for livestock management
Résumé
Animals kept for livestock or conservation form strong cohesive groups when foraging and moving, in the same
way as their wild counterparts. Collective decision-making involves making compromises by consensus to
maintain group cohesion and synchronisation. This type of consensus can be observed during collective
movements, when a leadership can emerge. In a distributed leadership, many group members may initiate
collective movements but some individuals initiate more frequently than others and are more frequently followed
by their conspecifics due to socio-demographic factors such as age, sex or dominance. In this study, we
focused on organisation and leadership in the collective movements of semi-wild groups of Highland cattle (Bos
Taurus). Highland cattle being often used in eco-pasture, studying leadership emergence and the use of space by
animals may improve livestock and pastureland management. We studied nine different compositions (i.e., same
location but with transfers of individuals) of four groups over a six-month period. The group sizes ranged from
nine to 21 individuals. Results revealed that leadership is widely distributed in Highland cattle groups, with
some individuals initiating more often than other group members. Indeed, in large groups, some group members
never initiated movements. The number of followers within a movement was particularly influenced by the age
of the initiator, its social centrality and dominance, but was also affected by the increase of pre-departure
activities. This study also shows the influence of several variables on the joining rank of individuals during
movement progression, such as age and social centrality. Finally, social centrality and the number of followers
explained the departure latency between two individuals. Here, we proposed how these findings can help
manage livestock.