Evaluating ammonia emission potential from concrete slat designs for pig housing

In growing-finishing pig houses, ammonia (NH3) is mainly produced by excreta on the concrete slatted floor surface and in the slurry pit. The objective of this study was to reduce the amount of NH3 emissions produced on the fouled floor surfaces of growing-finishing pig houses by finding a slat design that minimises the contact between excreta and concrete. Concrete slat prototypes were tested with regards to their NH3 emission potential under fouling simulations. Three factors were studied; the slats cross-section shape, the presence or absence of a notch along the slats, and the presence or absence of an epoxy coating applied to the slats. Slats were uniformly fouled with a urea–urease solution. Immediately after fouling, the slats were inserted in an environmental emission chamber and NH3 concentrations were measured at 2, 24, 48, 72 and 96 h after the fouling event. Emission rates were calculated for each of these five sampling events. Statistical analysis showed that only the presence of a notch had a significant effect on the reduction of NH3 emission rates. Compared with the control design that is typically used in pig houses, the presence of a notch resulted in average reductions between 23 and 42%.