Behaviour and performance of growing and finishing pigs depending on different housing conditions and sire breeds

Abstract

Although aggressive interactions between newly regrouped pigs are studied since the 1970s (Ewbank and Bryant, 1972; Peden et al., 2018) and tail-biting was even already mentioned in the 1940s , both problematic issues are still persistent in conventional pig husbandry, challenging farmers and putting the pigs at a welfare risk.Weaning is probably the most stressful event in a piglet's life . Under conventional housing conditions, piglets are usually weaned abruptly within one day at the age of three to four weeks (Council Directive 2008/120/EC) although it is known that weaning under (semi-)natural conditions happens gradually within four months . The separation from the dam, the relocation and regrouping induce a stress reaction accompanied by an increased synthesis of the stress hormone cortisol (Moberg, 2000; Cornale et al., 2015).The mixing of unfamiliar pigs leads to aggressive rank fights in order to establish a social hierarchy, which result in skin lesions Kanaan et al., 2008;, an impaired immune response and declined performance (Ekkel et al., 1995). Studies showed that pigs compensate stressful events individually different and that this coping strategies might lead to oral manipulation and biting of pen mates (Benus et al., 1991; Rushen, 1993). Therefore, the optimisation of the management at weaning and an adjustment in the housing conditions might be a way to reduce both, aggressive interactions at weaning and tailbiting at long-term (Schrøder-