Effects of environmental enrichment on decision-making behavior in pigs

The pigs increased the number of advantageous choices during the course of training. In the acquisition phase, barren-housed pigs chose the advantageous options more often compared to environmentally enriched pigs. No differences werer found during the retention phase. All pigs made less advantageous choices at the start of the retention phase than at the end of the acquisition phase. The level of hair cortisol was higher in the barren-housed than in the enriched-housed pigs. This difference was more pronounced after acquisition than after retention testing. No other differences were found for cortisol in saliva and hair. The environments did not differentially affect body mass at the end of the study. Summarizing, housing in a barren environment appears to be more stressful than housing in an enriched environment, as indicated by higher hair cortisol levels in barren-housed pigs, but it also improved acquisition of the PGT.