Chicory and red clover silage in diets to finishing pigs—influence on performance, time budgets and social interactions

Ley crops can be preserved as silage and can serve as a locally produced feedstuff/enrichment for pigs. It is important to determine the potential for using ley crops grown on-farm in pig production and to evaluate dietary inclusion of different roughage types on pig performance and behaviour. This study examined the influence of access to chicory or red clover silage, in combination with a restricted feeding regime, on pig performance, time budgets and social behaviour. In total, 72 finishing pigs were evenly allocated to three treatments: chicory silage, red clover silage and a control. Pigs in the control treatment were fed 100% commercial liquid feed according to the standards for growing/finishing pigs, while pigs in the chicory and red clover treatments were fed 80% commercial diet (energy basis) and whole-crop chicory or red clover silage ad libitum. Pigs in the chicory silage and red clover silage treatments grew 15 and 10% slower, respectively, than pigs in the control treatment; however, the slower growth rate was not as pronounced as the reduction of energy allowance in the commercial feed. Further, the pigs fed red clover silage had lower feed conversion ratio (based on the commercial cereal-based feed) than pigs fed chicory silage or the control diet, indicating that the red clover silage contributed some energy and nutrients to the finishing pigs. Moreover, pigs fed chicory or red clover silage were more active than control pigs and performed more feed-directed behaviours and less behaviours directed towards other pigs and pen fitting.