To reduce the risk of nutrient losses from free-range pigs, it is important to limit stocking density and to reduce nutrient inputs from concentrated feed.
Stimulating pigs’ nutrient intake from foraging. Utilising available biomass is an obvious strategy to improve the sustainability of free-range systems.
• Root foraging crops, like Jerusalem artichokes or sugar beet (photo 1), can cover more than 80 % and 50 % of the energy requirements of pregnant sows and growing/finishing pigs, respectively.
• Protein-rich foraging crops like Lucerne or grass/clover can provide 100 % of the lysine and methionine requirements of pregnant sows and 30-40 % of the lysine and methionine requirements of growing/finishing pigs when including estimated contribution from foraged soil organisms like earthworms
• If pig producers adopt restrictive feeding (limited access to concentrated feed) to stimulate foraging behav-iour, it is important to reduce competition for feed by allowing adequate time and space for feed consump-tion.
• As continuous access to attractive foraging crops stimulates pig foraging behaviour, it is important to consider and develop competitive moveable fences/systems.