Straw or silage provision influences feeding behaviour of pregnant sows in dynamic groups

Aggressive interactions in dynamic groups of sows occur predominantly on introduction of new animals to the group or when fi ghting for access to feed. The aim of this study was reduction of aggression through provision of additional straw or silage. Three dynamic groups of 47 sows were subjected to a Latin square design involving three treatments: daily provision of 50g straw per animal in the lying area (S), daily provision of 500g per sow of grass silage in racks above the slatted fl oor (G) and a control group (C). Straw and silage were provided at the start of the feeder cycle (7:30h). The Latin square was replicated twice. Each group stayed within one treatment for a period of six weeks. Every week four new sows entered each dynamic group. Sows were fed individually from an automated Fit-mix feeder system, which does not protect sows during feeding. Daily feed intake did not differ between treatments, but C sows had more feeding visits to the stations (57, 45 and 49 visits per sow per day for C, G and S sows respectively; P