SRP348815 PRJNA771754 The effect of suckling social contact of piglets It is well known that intensive breeding conditions can improve the performance of farm animals, but seriously damage animal welfare. In recent years, more and more people have a strong interest in animal welfare, European and American countries have also carried out corresponding legislation in the process of animal production. In order to improve animal welfare, combining piglets in their natural state at about 14 postpartum, sows will lead the piglets back into the herd, we provide piglets in the feedlot with the opportunity to interact with strangers in adjacent pens at 14 days of age. The results showed that the enriched social environment during lactation altered gene expression in hypothalamus, prefrontal lobe and colon of piglets. In colon, most of the differentially exposed genes were enriched in nutrient metabolism and absorption, and most of the differentially exposed genes were enriched in cognition and HPA axis in brain. This study will provide a theoretical evaluation of the effects of social contact on intestinal development of piglets during lactation.