Although pigs tend to separate lying and eliminating areas, one of the problems of intensive pig production is the occurrence of dirty lying areas in fattening pig pens resulting in a higher labour input and lower technical results. Slatted floors are hygienic and require less maintenance. The main disadvantage is that they offer little comfort since the requirements of a lasting, clean floor are incompatible with the requirements of a soft lying area. Furthermore, the development of welfare-friendly housing systems requires a better knowledge of the factors influencing a clear elimination/lying separation. This study's aim was to assess some factors that could e ncourage pigs to structure their environment in an hygienic manner i.e.: shelter, a mat and proximity of a trough, and further how these should be combined as to optimize the separation.

Two adjacent fully-slatted pens (3.70 x 2.30 m) housing three piglets each were used. Subjects were 13 weeks old when introduced into the pens and had been group-housed. Food (trough) and water (nipples) were available ad lib. Social behaviour and spatial distribution of the pigs were recorded. Defecation sites, room and foreseen lying area temperature, were recorded daily. A colour CCD camera, connected to a Panasonic AG-6730 time-lapse video cassette recorder, was aimed sideways at the pen. The VCR recorded 4 one-hour periods spread over the entire day (09.00, 12.00, 18.00, 21.00) during twenty days. A focal sampling analysis was carried out using The Observer Video-Pro software (Noldus Information Technology).

In the first experiment 3 piglets had a roof shelter (1 x 2.30 m) while the control group was housed in the barren pen. In a first period the trough was situated at the opposite side from the shelter close to the nipple. In the second one it was moved under the shelter. A new group of 2 x 3 piglets was used in the second experiment. Experimental piglets had a mat (1 x 2.30 m) instead of the shelter, the control group staying in the barren pen. In the second period the trough was moved on the mat.

A first analysis of the results showed that the pigs did not lie in the sheltered area. Instead they favoured to sleep close to the trough and kept that area clean. During the second period, the trough was moved under the shelter. This resulted in an immediate switch between the lying and dunging area. In the second experiment the piglets lied partly on the mat, partly on the slats. During the second period, the trough was placed on the mat, which resulted again in a switch between the former lying and dunging areas.

Regular registration of the temperature indicated that it had no influence on a relocation of the lying area. We conclude that, under the present conditions, the separation between lying and elimination area was essentially determined by the location of the feeding trough and not by the presence of a shelter or a mat.

© 2000 Noldus Information Technology b.v.