Influence of enrichment material and herbal compounds in the behaviour and performance of growing pigs

Pigs reared in barren conditions are exposed to many different stressors, compromising their welfare and producing physiological and behavioural changes. The aim of this study was to assess the effect of environmental enrichment (EE) consisting of natural hemp ropes, sawdust, rubber balls, and a herbal compound (HC) of Valerian officinalis and Passiflora incarnata on the behaviour and performance of growing pigs. Fifty-six pigs were used to assess four different treatments divided in two pens of seven animals per treatment (14 pigs/treatment). The treatments tested were: (a) pigs reared with EE, (b) pigs supplemented with HC, (c) pigs provided with both EE and HC, and (d) control group (CG, neither EE nor HC). Body weight and lesions were measured before starting the experiments (week 15) and at 18, 20, 22 and 24 weeks of age. Weekly instantaneous scan and continuous focal sampling were used to record behavioural patterns of activity, social interactions and abnormal behaviours. Three novel tests were carried out at 16, 19 and 23 weeks of age. Body weight at the end of the experiment was found to be significantly lower for the pigs reared in the control group compared to the other treatments (p = 0.0009). Furthermore, pigs reared with EE presented less stereotypies (p = 0.016) and redirected behaviour (0.0188), but more exploratory behaviour (p = 0.008). However, pigs supplemented with HC presented less social interactions (p = 0.048), a trend to present less negative social behaviour (p = 0.09) and less skin lesions (P = 0.0433) than pigs not supplemented. Finally, no remarkable differences were reported in any of the three novel tests. Thus, both EE and HC positively influenced some animal welfare indicators and performance of growing pigs in the present experiment.