Comparison of ammonia and greenhouse gas emissions from fattening pigs kept either on partially slatted floor in cold conditions or on fully slatted floor in thermoneutral conditions

Continuous measurements of ammonia and greenhouse gas were achieved on exhaust air from two fattening rooms differing by the type of floor (totally slatted vs partially slatted floor) and the ambient temperature. Temperature was regulated at 18°C in the room with partially slatted floor (room CP18) and 24°C in the room with fully slatted floor (CI24). Pigs were fed ad libitum. Daily feed intake, growth rate and carcass backfat thickness were significantly higher in pigs from room CP18 than from room CI24, whereas feed conversion ratio tended to be higher in CP18 pigs. Under cold conditions (18°C), the NH3, N2O, CH4 and CO2 daily emissions per pig on partially slatted floor were similar to those on fully slatted floor under thermoneutral conditions (CI24 : 8.9‐0.12‐7.3 and 676 g, CP18: 9.1‐0.15‐8.4 and 629 g, respectively). A further reduction of ammonia emission from pig units on partially slatted floor would require a more pronounced reduction of ambient temperature. However, in such conditions, a deterioration of feed conversion ratio and carcass leanness may be expected. Thus, the extra‐cost induced by the utilization of partially slatted floor in very cold ambient conditions would not be acceptable with regard to the definition of Best Available Techniques given by the IPPC directive.