Abstract

Under natural conditions, piglets have the opportunity to interact with non-littermates before weaning. Nevertheless, in intensive production systems, piglets only have contact with penmates during lactation. Social interactions can be encouraged by removing the barrier between litters whilst the sows are kept in their own crates. However, when piglets are co-mingled at the first days of lactation, studies have shown that a high percentage of them suck with their own mother during all the suckling period, regardless of nipples availability. This study aimed to investigate the effect of switching sows' positions between early co-mingled litters on suckling episodes, durations and maternal suckling. Eight sows' pairs were housed in adjacent pens before farrowing. Piglets were socialized by removing the separating barriers between two adjacent pens on day 2 post-farrowing. The position of four sows' pairs was switched at day 14 post-farrowing (Switched group), while the remaining four sows' pairs remained in their original crates (Control group). The suckling behaviour of piglets was video recorded during the whole experiment (day 2-23). After sows were switched, a decrease suckling duration was observed in Switched group (P = 0.015), a situation that was also observed when analysing one day before and after the change in position. (P = 0.018). The number of suckling episodes decreased in both groups (P 0.001) after sows were switched. However, when analysing one day before and after switching the number of suckling episodes increased (P 0.001). Maternal suckling decrease in both groups after sows were switched (P = 0.013). However, no differences were observed one day before and after the switching of sows. No effect of switching sows' position was observed on productive parameters of piglets (P 0.05). The suckling behaviour in early comingled piglets slightly change after the sows' position was switched at an intermediate stage of lactation. A decrease in the suckling duration and an increase in the number of episodes one day after sows were switched probably reflect a momentary confusion of the animals. However, although there may have been operant conditioning at the site of consumption, this was not enough to significantly reduce maternal suckling in contrast with previous literature that separated barriers at the middle of the suckling period, reinforcing the operant conditioning through a greater period of conditioning experience.