Different roughages to organic growing/finishing pigs — Influence on activity behaviour and social interactions

The effect of roughage on pigs' activity behaviour and social interactions was investigated at four observation occasions in this study, which was performed during two years and included two experiments of organic growing/finishing pigs. In experiment 1, 377 pigs were allocated randomly to either a control treatment (C) or one of three treatments with access to additional roughages; hay (H), grass silage (GS) or whole crop barley silage (BS). In experiment 2, 138 pigs were randomly allocated to the C or the GS treatment. Pigs were housed indoors with straw in the lying area and with access to a concrete outdoor run, where H, GS and BS pigs were given roughages ad libitum in hedges. Pigs given roughage were staying outdoors significantly more frequently than control pigs (p = 0.031 in experiment 1 and p = 0.002 in experiment 2) and were more active (p = 0.034 and p = 0.006, respectively). C pigs were rooting in straw more often than GS pigs and tended to root more often than BS pigs, which suggests that pigs with additional roughage are motivated to use it to explore and forage. However, no difference in time spent on eating the different roughages was found. Indoors, the frequency of aggressive behaviour in the lying area was lower for pigs with access to roughage than for pigs in the control treatment in experiment 1 (p = 0.009) and was lower, though not significantly, in experiment 2 (p = 0.121). Our results confirm that access to additional roughage in the outdoor area significantly influences the pigs to go outdoors more frequently and to be more active, and reduces the aggressive behaviour among the pigs.