Slurry funnels with frequent discharge and partial pit ventilation reduce ammonia, methane, and odorants emissions in sow housing

Livestock slurry is an important anthropogenic source of ammonia, methane, and odour. Novel techniques need to replace standard practices to mitigate emissions. This study explores a slurry system based on funnels with frequent slurry discharge and partial pit ventilation in an experimental pig house with farrowing pens for loose sows. In the control section, a flat bottom slurry system was installed and emptied only at the end of the batch. Ammonia and methane concentrations were quantified with cavity ring-down spectroscopy and odorants with proton-transfer-reaction mass spectrometry. Applying 30 % pit ventilation in both sections reduced ammonia emissions by approximately 50 % in the funnel section compared to the control. Without pit ventilation in the control, the ammonia emissions were 25 % lower in the funnel section with 30 % pit ventilation. Methane was 20–80 % lower in the funnel section and the odour activity value was reduced by more than 50 % in all batches compared to the control. Alternative pit ventilation percentages of 20 and 40 % revealed that the pit ventilation should not be higher than 30 % to avoid increased emissions The funnel system with frequent slurry discharge significantly reduces ammonia, methane, and odorants emissions relative to the control system. Furthermore, the inclusion of partial pit ventilation reduces NH₃ concentration above the slats providing a healthier environment for the sow and piglets.