Characterisation of sows' postures and posture changes with regard to crushing piglets

The aim of this study was to analyse different behavioural traits of sows to describe posture changes and to determine the influences of these traits on piglet losses. The behaviour of 386 German Landrace sows (with 438 pure-bred litters) was videotaped continuously starting 12 h prepartum until 48 h postpartum in a nucleus herd for 1 year. From this population, 40 sows were randomly sampled with a block data design. Twenty sows which crushed one or more than one piglet (C-sows) were compared to 20 sows which crushed no piglets (NC-sows). The postural behavioural traits were analysed according to duration, manner and frequencies of positions (descending-from-standing-lying behaviour, standing-up behaviour) as well as the time taken for various posture changes. Each respective trait was calculated according to the difference between NC-sows and C-sows. Results revealed that prepartum, NC-sows were more restless; primiparous ones in particular performed more posture changes (P = 0.109) and tended to stand up more often (P < 0.01). Additionally, they stood more often (P < 0.05) and performed nest-building behaviour with higher frequencies, particularly in the seventh (P < 0.01) and sixth hours (P < 0.1) before parturition and with longer durations than C-sows. Postpartum, NC-sows performed no different activities in movement pattern compared to C-sows. However, compared to primiparous NC-sows, primiparous C-sows showed more rolling movements (P < 0.01). C-sows preferred ventral recumbency within rolling movements (P < 0.05) and as the final position of descending from standing to lying (P < 0.1). Furthermore, the bouts of sitting behaviour of C-sows were much longer than of NC-sows, especially multiparous ones (P < 0.01). NC-sows performed lateral recumbency much longer and also more often as the final position of descending from standing to lying (P < 0.01). These results suggested that posture patterns of NC-sows and C-sows are different, especially nest-building behaviour prepartum and ventral or lateral recumbence postpartum, indicating a possible use to characterise the maternal abilities of sows in minimising piglet crushing.