Can straw or compost satisfy the rooting motivation of fattening pigs?

Summary

The aim of this study was to investigate whether straw or compost is more appropriate to satisfy the rooting motivation of growing-finishing pigs. In total, 57 pigs were housed in three pens with either minimal straw, deep straw, or compost. Preference for rooting (apple slices hidden in sawdutst) or feeding (directly accessible apple slices) was assessed using Conditioned Place Preference tests (CPPT) and preference tests (PT). For CPPT, pigs were trained to associate chambers with one of the stimuli; in PT, stimuli were presented in troughs next to each other. The first decision (“rooting” or “feeding”), duration per stimulus, and latency to decision were recorded. Pigs housed in pens with minimal straw tended to enter the rooting chamber first in CPPT (p=0.1). Treatment had no effect on the duration of stay per chamber. In PT, pigs housed in pens with compost chose "feed" more often than the other pigs in their first decision (p=0.02). Because the results of the two behavioral tests were not consistent, we cannot conclude whether straw or compost is more appropriate to satisfy the rooting motivation of finishing pigs.