animals Article Social Network Analysis of Agonistic Behaviour and Its Association with Economically Important Traits in Pigs Saif Agha 1,2,* , Emma Fàbrega 3 , Raquel Quintanilla 1 and Juan Pablo Sánchez 1 1 Animal Breeding and Genetics, Institute for Food and Agriculture Research and Technology (IRTA), Caldes de Montbui, 08140 Barcelona, Spain;
[email protected] (R.Q.);
[email protected] (J.P.S.) 2 Animal Production Department, Faculty of Agriculture, Ain Shams University, Shubra Alkhaima, Cairo 11241, Egypt 3 Animal Welfare Program, Institute for Food and Agriculture Research and Technology (IRTA), Monells, 17121 Girona, Spain;
[email protected] * Correspondence:
[email protected] Received: 25 September 2020; Accepted: 12 November 2020; Published: 16 November 2020 Simple Summary: Aggression behaviour has several negative consequences on the performance and welfare of pigs. Here, a Social Network Analysis (SNA) approach was employed to (1) identify individual traits that describe the role of each animal in the aggression; (2) investigate the association of these traits with performance and feeding behaviour traits. The study was conducted on 326 Duroc pigs reared in 29 pens. Several individual centrality traits were identified and used to calculate the Social Rank Index. The Dominant, Subordinate, and Isolated animals represented 21.1%, 57.5% and 21.4%, respectively. No significant correlations were observed between out-degree (number of initiated agonistic behaviours) and growth traits, indicating the similarity of growth patterns for dominant and non-dominant animals. Furthermore, out-degree was correlated positively with average daily occupation time (time at the feeder/day) and average daily feeding frequency (number of visits to the feeder/day), but negatively with average daily feeding rate (gr/min).