Confinement of sows 24Â h before expected farrowing affects the performance of nest building behaviours but not progress of parturition

The effects of confinement prior to farrowing on the performance of nest building behaviour and progress of parturition were investigated using hyper prolific sows. Forty first parity and 41 second/third parity sows were allocated to one of two treatments: loose housed (40) or confined (41). All sows had free access to a straw rack with long stemmed straw and were housed in a freedom farrowing pen with an option of confinement. Loose sows were loose housed throughout the observational period and confined sows were confined from 2 days before expected farrowing until the completion of parturition. Sows were video recorded from 2 days before expected farrowing until birth of the last piglet, and behaviours (biting/rooting pen fittings, straw directed and rooting/pawing floor) and postures (lying sternal, lying lateral, sitting and standing/walking) of the sows during the last 24 h before farrowing were recorded continuously. The time of birth of every piglet was recorded from the video recordings, and it was noted if the piglet was alive or stillborn. Treatments were compared by use of linear models with treatment and parity as fixed effects. Results showed that confinement did not influence duration of the nest building period, but affected the performance of nest building behaviour. Loose housed sows tended to perform more nest building behaviour during the nest building period than confined sows (817 (95% CI: 713-929) vs 686 (590-789) s/h/sow, P = 0.08). Loose housed sows had fewer bouts of nest building behaviours than confined sows (4.6 ± 0.48 vs 6.1 ± 0.48 bouts/sow/h, P = 0.03) but mean duration of bouts was longer (154 (95% CI: 136-173) vs 98 (83-114) s/bout, P < 0.001). Loose housed sows tended to spend a greater proportion of time during the nest building period standing/walking (21 ± 1.33 vs 17 ± 1.33 min/h, P = 0.05). Overall, salivary cortisol concentrations were lower in confined compared with loose housed sows (13 vs 20 nmol/L, P < 0.001). No differences were found in total born piglets per litter (L: 17.4 ± 0.4; C: 17.6 ± 0.4, P = 0.70), the duration of farrowing (L: 283 min; C: 258 min, P = 0.38), mean birth interval (L: 17.4 min; C:15.7 min, P = 0.30), or number of stillborn (L: 0.5; C: 0.7, P = 0.18). In conclusion, loose sows spent a greater proportion of the nest building period performing nest building, especially rooting and pawing behaviours, in comparison with confined sows. Furthermore, loose housed sows were standing or walking more than confined sows, but housing did not affect duration of farrowing or piglet birth intervals.