Damaging Behaviour and Associated Lesions in Relation to Types of Enrichment for Finisher Pigs on Commercial Farms

SIMPLE SUMMARY: EU legislation states that all pigs must have access to material that allows them to perform investigation and manipulation activities. This reduces the risk of pigs performing damaging behaviours (e.g., tail, ear and flank biting). The aim of this study was to determine associations between damaging behaviours performed by finisher pigs, the related lesions and the use of different types of enrichment. Finisher pigs were observed on 31 commercial pig farms in Ireland and the number of pigs affected by tail, ear and flank lesions as well as all occurrences of damaging behaviour (tail-, ear- and flank-directed behaviour) were recorded. The type (chain, plastic or wood) of enrichment provided was noted; chains were the most common (41.4% of farms), followed by plastic (37.9%) and wood (20.7%). Damaging behaviour was more frequent on farms that provided chains compared to plastic or wood, particularly tail- and flank-directed behaviour was affected. The prevalence of lesions tended to be higher on farms where chains were provided compared to wooden enrichment devices. This was due to a higher prevalence of mild tail lesions on farms using chains. Results suggest that despite chains being commonly used, they did not fulfill their role in reducing damaging behaviours and associated lesions in finisher pigs. ABSTRACT: EU legislation states that all pigs must have access to material that allows them to perform investigation and manipulation activities, thereby reducing the risk of pigs performing damaging behaviours (e.g., tail, ear and flank biting). We aimed to determine associations between damaging behaviours performed by finisher pigs, the related lesions and the use of different types of enrichment. Six randomly selected pens of finisher pigs were observed for 10 min each on 31 commercial pig farms in Ireland. All pigs were counted and the number of pigs affected by tail, ear and flank lesions was recorded. During the last 5 min, all occurrences of damaging behaviour (tail-, ear- and flank-directed behaviour) were recorded. The type (chain, plastic or wood) and number of accessible enrichment objects/pen was recorded. Chains were the most common (41.4% of farms), followed by plastic (37.9%) and wood (20.7%). Damaging behaviour was more frequent on farms that provided chains compared to plastic or wood. Farms with chains were associated with a higher frequency of flank-directed behaviour and tended to be associated with a higher frequency of tail-directed behaviour compared to farms that provided plastic devices. The prevalence of lesions tended to be higher on farms where chains were provided compared to wooden enrichment devices, mostly driven by a difference in the prevalence of mild tail lesions. Results support expert opinions that despite being commonly used, chains did not fulfill a role in reducing damaging behaviours and associated lesions in finisher pigs compared to other forms of enrichment.