Clean floors as ammonia mitigation strategy in dairy barns

Background and Objective

Keeping dairy cattle in loose housing contributes to the total emission of ammonia up to 50% and has its main origin from soiled walking areas like slatted floors. The ammonia emissions from the barns have an impact on the environment, as does the soiled floor on the health of the claws.

Thus, the objective of our study was to evaluate the impact of the manure removal from slatted floor on the ammonia emission in dairy barns.

Approach

The cleaning system used is designed to combine the advantages of a wet and a mechanical cleaning-method. It features high-pressure water nozzles, mechanical star discharge rotors and a rubber-scraper.

For the experiment, six exchangeable concrete slatted floor elements (55cm x 62cm x 20cm) were cut out of the existing floor. This way the test elements could be separated from other sources of ammonia emission and moved into closed chambers (120cm x 80cm x 60cm). Via membrane pumps the air carrying emitted ammonia from the slats was run through a solution of sulphuric acid (0,1n) and determined quantitatively in a lab using a photometer.

Results

Compared to untreated control slats, a reduction of the amount of manure weighted on the clean test elements up to 33.2% could be observed. However, no significant effect of the cleaning of the slats on the ammonia emission could be detected. Average ammonia concentrations measured directly after the cleaning (mean temperature in the barn: 21.1°C) were 13.2 mg NH₃ h^-1 m^-2 (clean) and 16.3 mg NH₃ h^-1 m^-2 (control), respectively.