Straw is frequently supplied as a rooting material to improve the welfare of pigs. In Denmark, organically raised slaughter pigs must have access to both straw and roughage. In order to evaluate whether roughage can he used as an appropriate rooting substrate for pigs, the effects of six different roughage types on pigs’ behaviour was examined. Pairs of 11-week-old pigs were placed in specially designed 4 m2 pens. Each pen contained a self-feeder for cereal, a water bowl, a box for roughage, a straw- bedded area and a dunging area. Four replicates were carried out, each consisting of seven pairs of pigs. In each replicate, each pair of pigs was supplied with either whole-crop silage of oats, vetch and lupin (Avena sativa, Vicia sativa, and Lupinus luteus (OVL), whole-crop silage of barley and peas (Hordeum vulgare and Pisum sativum ssp. arvense) (BP), whole-crop silage of clover and grass (Trifolium repens and Lolium perenne (CG), green grass meal (Poa ssp.) (GM), hay of clover and grass (Trifolium repens and Lolium perenne (H), fodder beets (Beta vulgaris ssp. vulgaris) (B), or no roughage (the control treatment) (CON). The pigs manipulated OVL for longer than the other roughage products (P < 0·01). When OVL was omitted from the analysis, B was manipulated for longer than CON (P < 0·05). The pigs that were offered CON manipulated equipment for a longer time than pigs offered B (P < 0·05) and tended to manipulate equipment for longer than pigs offered OVL (P = 0·065). Interestingly, OVL and B were the two products with the lowest dry-matter content. It may suggest that the amount of time spent manipulating roughage will depend considerably on the specific characteristics of the roughage offered, for instance dry matter content and complexity but probably also texture, smell and taste. In addition, the time spent manipulating other elements in the pen will depend on the type of roughage offered. In conclusion, the present study shows that some, but not all, types of roughage are suited as an enrichment of the pig’s environment.
