Impact of early socialization environment on social behavior, physiology and growth performance of weaned piglets

Abstract Weaning and mixing cause substantial social stress among piglets and frequently lead to stress, injury, inflammation, immunosuppression and growth retardation. This study aimed to investigate the effects of different early social environments on social behavior, physiology and growth performance of weaned piglets. In total, 133 YDM (Large White × DM [Duroc × Min pig]) piglets from 12 litters were studied from weaning (35 day-old) to the end of the nursery period (63 day-old). Three pre-weaning treatments were examined: intermittent contact (INT, 4 litters), piglets of two neighboring litters were socialized twice a week for 3 h from day (D) 14 to D35; continuous contact (CONTIN, 4 litters), piglets of two neighboring litters were socialized from D14 to D35; non contact (NC, 4 litters), the other 4 litters were kept separate. After weaning, NC piglets were randomly regrouped into 4 new litters as the control group (CON, 4 litters); 4 litters of INT were mixed with nonadjacent litters from same group as the intermittent mixing group (IM, 4 litters); similarly, CONTIN was regrouped into the continuous mixing group (CM, 4 litters). The results revealed that within 72 h after mixing, the number of fighting in CM CON (P = 0.024). This study revealed that intermittent socialization pattern had positive effects on social behaviors, growth performance and physiology of piglets after weaning. Intermittent socialization patterns may be helpful for improving the welfare of weaned piglets, but further confirmation is necessary.