Effects of prepartum housing environment on abnormal behaviour, the farrowing process, and interactions with circulating oxytocin in sows

We evaluated the effects on sows of prepartum housing environment on bar-biting (BB) behaviour prior to parturition, farrowing duration from first to tenth piglets, litter size, and circulating oxytocin (OT) concentrations during birth of the first five piglets. A total of 35 sows, approximately seven days before the expected parturition date, were housed in: (1) CRATE (N = 11): the farrowing crate closed (210 × 80 cm), with provision of a bucketful of sawdust, (2) PEN (N = 12): the farrowing crate opened, with provision of a bucketful of sawdust, and (3) NEST (N = 12): the farrowing crate opened, with provision of abundant nesting materials. All sows were crated without additional supply of nesting materials when parturition started. Plasma samples from farrowing sows were collected via an indwelling catheter at 0, 2, and 4 min, after delivery of each of the first five piglets to assess circulating OT concentrations. Prepartum BB behaviour was observed in sows for a 20 min period each hour, from 18 h prior to parturition to the birth of the first piglet. Farrowing intervals were monitored between birth of the first and fifth piglet, and duration was recorded until the tenth piglet was born. Prepartum sows in CRATE showed higher frequency and tendency for increased total duration in BB behaviour than in PEN or in NEST (P < 0.05, P < 0.10, respectively). Prepartum housing environment did not affect circulating OT concentrations in sows while the first five piglets were born, or piglet stillbirths (P > 0.10). Farrowing duration between birth of the first and tenth piglet was shorter in sows with prepartum confinement than for those not confined (P < 0.05). Average farrowing intervals during birth of the first five piglets tended to be shorter in sows crated prepartum compared with non-crated sows (P < 0.10). OT during prepartum was correlated with OT concentrations during farrowing (r = 0.40, P < 0.0001). However, circulating OT concentrations during both periods were not correlated with farrowing performance or duration. In conclusion, the provision of nesting materials, space or both prior to parturition could reduce BB behaviour in prepartum sows. However, crating at the beginning of parturition after housing in open-crates during prepartum could increase farrowing intervals and duration in sows, possibly due to additional stress induced by sudden confinement.