Interactions of growing pigs with four different applications providing straw

Pigs are often housed in barren intensive housing systems but according to council directive 2008/120/EC, they must have access to enrichment materials. In order to be successful, enrichment should be destructible, edible, nutritional and dung-free. Straw seems to be an interesting enrichment material but is not a practical option for fully-slatted systems. Producers must therefore provide straw applications to reduce straw waste through the slatted floor. Both the type of straw used and the design of the application might influence the interest for and the effectiveness of the materials. It is therefore designated to verify differences in ways to present enrichment materials, in order to detect applications which are less interesting for pigs. To this end, four straw applications were tested simultaneously (1 enrichment application per pen) during 4 cohorts, presenting them each time during two weeks to 6 pigs (total n = 96) in pens with slatted floors. The four applications tested were a straw rack (long-stemmed straw), a straw feeder (long-stemmed straw), a MIK Toy (in rolls pressed chopped straw) and the Ikadan Straw Dispenser with chopped straw. All pigs had ad libitum access to straw from one of the applications. Behaviour was recorded using video cameras. Data were analysed per individual pig for week 1 and week 2 separately using the logistic mixed model. The daily used straw quantity per pen was registered during the entire test period. The quantity of straw use was the highest in presence of the straw rack (P < 0.0001), with an average straw use of approximately 2 kg per pen (6 pigs) per week. Straw use did not differ between week 1 and week 2 for any of the applications, but manipulative behaviour towards the application decreased for all applications during week 2 compared to week 1. This suggests a decrease in the required time to intake straw from the applications. In presence of the straw feeder, most of the time only one pig was occupied with the application, while in presence of the straw rack, the MIK Toy and the Funbar, more pigs interacted simultaneously with the device (P < 0.0001). Pigs spent more consecutive scans interacting with the straw rack and the straw feeder (P = 0.0003), which could be explained by the use of long straw with these applications. The results show that the duration of interactions with the applications might depend on the type of straw that is used. This study was funded by the Federal Public Service of Health, Food Chain Safety and Environment (Contract RT 12/02 SUCANNIB).status: publishe