Inhibiting urease activity to reduce ammonia emissions from dairy houses through application of disinfectants on different floor types

Limiting urease activity on barn floors offers a source-oriented approach to reduce ammonia (NH₃) emissions from dairy houses. This study aimed to find promising disinfectants and test the optimal application frequency to reduce urease activity. First, we investigated the short-term and long-term impact of spraying disinfectants (neutral electrolysed oxidising water (N-EOW), peracetic acid (PAA), hydrochloric acid and formaldehyde) on the urease activity of a standard concrete slatted (SCS) floor, plastic-coated slatted (PSL) floor, and grooved solid (GSO) floor. The promising disinfectants were tested for optimal spraying frequencies. Finally, we tested the impact of N-EOW and PAA on NH₃ emissions. The urease activity of PSL floors was significantly lower than that of SCS and GSO floors, 52, 254 and 2004mg (NH₄⁺ –N) m⁻² h⁻¹, respectively (P < 0.001). PAA and N-EOW were effective in reducing urease activity compared with water and other disinfectants. Long-term reduction of urease activity (for 120 h) was 76 % and 50 % for PAA and N-EOW. During weekly spraying, average urease reduction efficiencies for GSO floors were 76 % for N-EOW and 78 % for PAA immediately after application, but these decreased to 29 % and 34 % a week later. Although PAA is a well-known oxidising agent, N-EOW, may be a safer solution for animals and the environment. This study offers insight into the potential of disinfectant spraying (e.g., spraying N-EOW every 1–2 days) in combination with frequent manure removal to reduce NH₃ emissions. When transferring the results into practice, a comprehensive evaluation, however, is still required.