Pre-lying behaviour patterns in confined sows and their effects on crushing of piglets

In order to determine the influences of different posture patterns of sows on piglet losses, the present study aimed at the analysis of different elements of pre-lying behaviour peri and post partum. Over the course of 1 year, the behaviour of 386 German Landrace sows (with 438 pure-bred litters) in a nucleus herd was videotaped continuously starting 12 h ante partum until 48 h post partum. From these animals, 40 sows were randomly sampled with a block-data design. Twenty sows which crushed one or more than one piglet (designated as C-sows) were compared to 20 sows which crushed no piglets (designated as NC-sows). The analysis covered the frequency, duration and manner of the sows’ pre-lying behaviour. Combinations with other positions were assessed. The piglets’ resting-activity cycles and their location regarding the sow were also recorded. The respective behaviour was calculated according to the differences between NC-sows and C-sows. Results showed that post partum, NC-sows – in particular primiparous ones – performed ‘sniffing’ as an element of pre-lying behaviour significantly more often and with longer duration (30 s) than primiparous C-sows. Before ‘kneeling down on their front legs’ and changing into ‘lateral recumbency’, the primiparous NC-sows ‘sniffed’ more often than the C-sows (P < 0.01). Furthermore, NC-sows – especially multiparous ones – ‘looked around’ more often, also towards the piglet's nest site, before descending from standing to lying by ‘kneeling on front legs’ (P < 0.05). ‘Nosing’, often in combination with ‘looking around’, was significantly more frequent in primiparous NC-sows than in primiparous C-sows. The duration of the sleeping and activity behaviour at the mammary gland had a tendency to be longer in the piglets of C-sows than in those of NC-sows (P < 0.1). Thus, these results indicate that elements of pre-lying behaviour of NC-sows and C-sows are performed in different ways. Therefore, ‘sniffing’, ‘looking around’, and ‘nosing’ as components of the pre-lying behaviour represent useful elements to characterise the maternal responsiveness of sows in relation to the crushing of piglets.