Influence of amino acid level and production system on performance, health and behaviour in organic growing pigs

The influence of dietary amino acid levels (recommended, 7% and 14% lower) on performance and carcass quality was studied in organic indoor and outdoor pigs fed ad libitum in a 2-phase feeding system. The outdoor pigs grew faster during phase 2 than the indoor pigs (p=0.001), although feed conversion ratio did not differ (p=0.358). Dressing percentage was higher for outdoor than for indoor pigs (p=0.011) but lean meat content did not differ (p=0.904). The results indicate a discrepancy between pigs housed in different production systems rather than between pigs directed to different dietary amino acid levels. This suggests that growing/finishing pigs fed ad libitum can compensate for dietary amino acid levels lower than the current Swedish recommendations without affecting production results. Behaviour was affected by production system and showed that outdoor pigs walked significantly more (p=0.012) and tended to be rooting more (p=0.098) than indoor pigs. Sniffing, nibbling, pushing (p=0.001 for all) and tail manipulation (p=0.002) occurred more often indoors than outdoors. The incidence of pigs seropositive to erysipelas was higher outdoors (χ2-test; p=0.001). Ascaris suum infections were present in both production systems, whereas Eimeria sp only was found among outdoor pigs