A number of welfare and production problems are associated with weaning piglets including belly-nosing, ear and tail-biting, depressed immune responses, low intake of pelleted feed and impaired growth rate. These problems are, however, less pronounced in piglets reared on outdoor systems, which initially consume more pelleted food and show less belly-nosing and ear and tail biting than comparable indoor reared piglets. The objective of this study was to investigate how these differences in post weaning behaviour relate to the piglets' pre-weaning behaviour in the two rearing environments.

The study was carried out on a 200 sow breeding herd (Camborough line 12) with sows equally divided between extensive and intensive systems. In the intensive system, sows were singly housed prior to farrowing in crates and their piglets received a pelleted “creep” feed prior to weaning. On the outdoor system, sows were allowed to build straw nests in arks for farrowing and both sow and piglets had access to pasture. Each ark had observation holes in the front and back to allow sampling of the piglet's behaviour without disturbing the sow. Indoor and outdoor piglets were weaned at three weeks of age and mixed together in groups of 90-120 in straw-yard housing with access to a pelleted feed.