• Intra-Group Lethal Gang Aggression in Domestic Pigs (Sus scrofa domesticus)

      Camerlink, Irene; Chou, Jen-Yun; Turner, Simon P.; European Cooperation in Science and Technology; Scottish Government Strategic Research (MDPI AG, 2020-07-28)
      Intraspecific coalitional aggression is rare among all species, especially within stable social groups. We report here numerous cases of intraspecific lethal gang aggression within stable groups of domestic pigs. The objective was to describe this extreme aggression and to identify potential causes. Management data were collected from farms with (n = 23) and without (n = 19) gang aggression. From one farm, 91 victims were assessed for skin injuries and body condition score. Lethal gang aggression was significantly associated with deep straw bedding, which may be related to various other factors. Gang aggression tended to occur more in winter, and was unrelated to genetic line, breeding company, group size or feed type. It occurred equally in female-only and mixed sex groups (male-only groups were not represented), from around eight weeks of age. Injuries typically covered the whole body and were more severe on the front of the body. Victims who survived had a lower body condition score and fewer injuries than victims found dead. There are still many unknowns as to why this abnormal social behaviour occurs and it deserves further research attention, both for its applied relevance to animal welfare as for the evolutionary background of lethal gang aggression.
    • Multi-Step Tail Biting Outbreak Intervention Protocols for Pigs Housed on Slatted Floors.

      Chou, Jen-Yun; O'Driscoll, Keelin; D'Eath, Rick B; Sandercock, Dale A; Camerlink, Irene; European Cooperation in Science and Technology; Teagasc Walsh Fellowship Programme; Department of Agriculture, Food and the Marine; Rural & Environmental Science & Analytical Services, Scotland (MDPI, 2019-08-20)
      Solutions are needed to keep pigs under commercial conditions without tail biting outbreaks (TBOs). However, as TBOs are inevitable, even in well managed farms, it is crucial to know how to manage TBOs when they occur. We evaluated the effectiveness of multi-step intervention protocols to control TBOs. Across 96 pens (1248 undocked pigs) managed on fully-slatted floors, 40 TBOs were recorded ( 3 out of 12–14 pigs with fresh tail wounds). When an outbreak was identified, either the biters or the victims were removed, or enrichment (three ropes) was added. If the intervention failed, another intervention was randomly used until all three interventions had been deployed once. Fifty percent of TBOs were controlled after one intervention, 30% after 2–3 interventions, and 20% remained uncontrolled. A high proportion of biters/victims per pen reduced intervention success more so than the type of intervention. When only one intervention was used, adding ropes was the fastest method to overcome TBOs. Removed biters and victims were successfully reintroduced within 14 days back to their home pens. In conclusion, 80% of TBOs were successfully controlled within 18.4 1.7 days on average using one or multiple cost-effective intervention strategies.