SOW BODY MOVEMENTS THAT CRUSH PIGLETS - A COMPARISON BETWEEN 2 TYPES OF FARROWING ACCOMMODATION

Crushing by the sow is a major cause of death for piglets. The behavio r of 20 sows and their litters kept in two types of farrowing accommod ation (farrowing crates and more open pens) was video recorded for 4 d ays after farrowing. In total, 24 piglets were killed by maternal crus hing during the study (four in the farrowing crates, 20 in the pens). On 98 other occasions (30 in the farrowing crates, 68 in the pens) pig lets were trapped beneath the sow but survived this 'near-crushing'. E ight categories of sow body movements were recorded, including five ty pes of transition between lying, sitting and standing, and three types of rolling movements. The frequency of these different movements vari ed between the two types of farrowing accommodation: for example, tran sitions from lying to sitting and from sitting to lying were more comm on in crates than pens (1.92 vs. 0.92 movements per sow per h), and ro lls from the side to the udder and from the udder to the side were mor e frequent in the pens than crates (1.03 vs. 0.75 movements per sow pe r h). The rolling movements crushed piglets in pens (10 crushings) but not in crates, and the transitions between lying and sitting crushed piglets in crates (three crushings) but not in pens. The speed of roll ing movements differed between the two types of farrowing accommodatio n. Rolling movements from the udder to the side required on average 12 s in pens vs. 20 s in crates. In both types of accommodation, more cr ushing occurred on the day of farrowing (0.05 crushings per sow per h) than during subsequent days (0.01 crushings per sow per h), and more while farrowing was in progress (0.11 crushings per sow per h) than du ring the rest of the day of farrowing (0.03 crushings per sow per h). The probability of a piglet dying was strongly related to the amount o f time it was trapped under the sow. Of 84 piglets trapped less than 1 min only four were killed, whereas 16 died of the 24 that were trappe d for more than 4 min. These results indicate that piglets an crushed by several different body movements whose relative importance depends on the design of the farrowing environment.