The nose-ringing of outdoor pigs (Sus scrofa), although commonly practiced as a means to inhibit rooting behaviour and therefore reduce pasture damage and soil erosion, has been questioned on ethical grounds and alternatives are being sought. In this experiment, the effect of overground environmental enrichment was assessed as a possible alternative. 12 multiparous sows were housed in groups of four and randomly allocated to one of three treatments in a 3 × 3 Latin square design. Treatments were: 1) no environmental enrichment, 2) edible overground enrichment in the form of grass silage, and 3) inedible overground enrichment in the form of branches and tyres. Sows that received silage as overground enrichment spent significantly less time rooting the paddock (P < 0.01) than did sows on the other two treatments. The absence of a significant difference between treatments in overall foraging time budgets suggests that the manipulation of edible substrates may substitute for rooting behaviour in outdoor sows.
