Effects of a high protein starter diet with fermented soybean cake on growth performance of organic pigs weaned outdoor

•A high protein starter diet with fermented soybean cake was tested under organic European conditions.•Organic pigs weaned outdoor benefitted from being fed the high protein starter diet.•The high protein starter diet improved daily gain by 8% and feed efficiency by 12%.•The high protein diet reduced the estimated nitrogen excretion of outdoor organic weaners.•Subjective evaluation showed no effect of dietary treatment on post-weaning diarrhea.