Ammonia and odour emitted from deep litter and fully slatted floor systems for growing-finishing pigs

Two identical pig rooms, with mechanical ventilation, were used to compare the environmental impact of a deep litter fermentation system for growing-finishing pigs with a fully slatted floor system. The pig manure in the fully slatted floor room was removed manually twice daily, but in the fermented deep litter room, no manure was removed. Indoor and outdoor temperature, relative humidity, and ammonia concentration were measured continuously during the whole experimental period. Odour was sampled and analysed using the triangle odour bag method for 15 days during the experimental period. The performance of the pigs was not significantly different between the floor types. There were significant differences for both NH3 concentrations and emissions according to floor type (p < 0.001). NH3 emissions from pigs raised on the slatted floor and on the fermented deep litter were 8.82 and 2.16 g d−1 pig−1, respectively. Emissions increased from the first period to the second by about 4.9 times for NH3 with fully slatted floor and 1.1 times for NH3 with fermented deep litter. The parameters of floor type, pig weight, outdoor temperature and ventilation rate explained most of the variability of NH3 emissions. There were significant differences in odour concentration as odour units (OU), between floor types (p < 0.01). Mean odour concentrations during the whole experiment were 105.4 OU for the slatted floor room and 67.5 OU for the deep litter room. It was concluded that the deep litter fermentation system for pig production shows advantages in reductions of ammonia and odour.