Reduction of the number of slots in concrete slatted floors for fattening buildings : consequences for pigs and environment

The aim of this study was to compare two types of floors for fattening pigs with different percentage of open area. For the first room (noted control room), the whole surface of the pen floor was made with classic concrete slats with 15% open area (8 cm wide slats and 1.8 cm wide gaps).For the second room (noted mixed room), the floor was made with the same concrete slatted floor on the last third of the pen (back). For the remaining of the surface, the number and the size of slots were reduced to reach 5% open area.Performance was identical for both rooms except for the second replicate. At the beginning of the fattening period, pigs in the mixed room were less present at the back of the pen, which was dirtier. Later, pig repartition was similar in both rooms but the last third of the pen remained the major dunging area (60% and 47% of the whole dry matter excreted for mixed and control rooms respectively). Pigs were dirtier in the mixed room, as well as the floor (middle and back thirds), resulting in more ammonia emission (extracted air). Nevertheless, air quality (ammonia in the ambiance, dust and odours) was similar in both rooms.This floor design can be considered as a first step in the conception of new pen in order to improve welfare and to protectenvironment. Modifications could consist in replacing concrete by metal slats, increasing gap-width of the concrete slatted floor at the back of the pen or increasing the slatted floor area.