Effects of different enrichment devices on some welfare indicators of post-weaned undocked piglets

Two experimental trials were carried out in order to test the effectiveness of different environmental enrichments in improving the welfare of weaned pigs. A total of 120 undocked piglets was used. In trial one, group C1 received a metal chain and group WL a wooden log mounted on a frame. In trial two, the enrichments proposed were a hanging chain (group C2), an edible block (group ED) and a wooden briquette (group WB) mounted on a frame. The effectiveness of the enrichments was assessed in terms of animal behaviour, cortisol from bristles, hematologic and hematic profiles, cutaneous (skin and tail) lesions. Growth parameters were also recorded. Although some differences were detected in growth parameters in trial 1 (with C1 group having better productive outcomes than WL group) and some minor differences were observed in animal behaviour in both trials, the overall welfare status did not differ among the experimental groups. On the other hand, no welfare issues emerged in groups C1 and C2, receiving the enrichment device which is generally believed to be scarcely attractive, i.e. the hanging chain. We can therefore conclude that, if no managerial errors are made (floor space availability, feed inadequacy, group stability, microclimate, illumination), under the tested experimental conditions, hanging chains can provide a sufficient environmental enrichment for undocked piglets, even when compared to more attractive enrichments (e.g. an edible block).