Use of different wood types as enrichment to reduce tail biting in pigs managed on fully-slatted floors

Tail-biting is a serious issue in pig farming, with significant negative effects for pigs and farmers alike. This study aimed to find an economically feasible and effective solution on farms managed on fully-slatted slurry systems to reduce tail-biting, focusing on assessing the adequacy of using wood as environmental enrichment. Four different wood types (beech, larch, spruce and Scots pine) were assessed. A total of 800 tail docked finisher pigs on an Irish commercial farm were used, with 8 pens (n=25 pigs/pen) provided with each wood type, conducted over time in 2 replicates (16 pens/replicate). In each pen a single wooden post was offered to the pigs in commercially available metal wood dispensers. Two chains hung from either side of the bottom of the holder. The length, weight, moisture level and hardness of the wood were measured weekly. Tail and ear lesion scores, tear-staining, tail posture, and direct behaviour observation of pigs were carried out every other week. Carcasses were inspected in the slaughterhouse for further verification of tail damage and condemnation records. Results showed that spruce was consumed significantly more quickly than other types of wood in terms of weight loss and reduction in length of the posts (p<0.001). With regard to time spent interacting with the wood, pigs were observed using the spruce more frequently than the other wood types (p<0.05). Pigs also interacted with the wood more often than the chains in spruce pens (p<0.001). However, there was no difference in the frequency of harmful behaviours (tail/ear/flank-biting) observed between treatments. There was a positive correlation between ear lesion and tear-staining scorings (rp=0.286, p<0.01), and between tail lesion and tail posture scorings (rp=0.206, p<0.05). These results indicate that tail posture and tear staining could have potential as on-farm welfare assessment tools to inspect the severity of pen-level tail and ear biting respectively. No visceral condemnation that could be associated with wood use was found in the factory, and different wood types did not affect the average daily gain of pigs. There were no difference in the effectiveness of the different types of wood in reducing tail or ear damage, but levels were low in all treatments. Further work will focus on detailed analysis of pig behaviour with these wood types, and using undocked pigs.