Nose-clip use in semi-free ranging pigs reduces rooting without disrupting affiliative behaviour or causing prolonged stress

Domestic pigs (Sus scrofa) raised under natural conditions can show their complete behavioural repertoire. However, rooting behaviour can have a great impact on the environment. In the context of the promotion of farm animal welfare and environmental concerns, this study investigated the potential of nose-clips as a less invasive alternative to nose-rings for the management of rooting behaviour of free-ranging pigs. We collected behavioural data and salivary cortisol levels on two groups: an experimental group (n = 17) with nose-clips and a control group (n = 17) without nose-clips. After the nose-clipping, we observed a temporary increase in anxiety-related behaviour and cortisol levels during the 1st week, followed by a return to pre-application levels in the following weeks. We found a temporary decrease in affiliative interactions involving the nose during the 1st week after the application of nose-clips, whereas no differences in affiliative interactions without nose contact and aggression levels were observed. Moreover, nose-clips effectively reduced destructive excavation behaviours, without leading to a simultaneous increase in other exploratory behaviours. In conclusion, our findings show that nose-clips could be a solution that mitigates destructive rooting while preserving social interactions and animal welfare. Further research is essential to consolidate these findings and assess the long-term implications of this approach.