Ammonia emission from dairy cow buildings: a review of measurement techniques, influencing factors and possibilities for reduction

Abstract

This study aimed to make an analytical inventory of ammonia emission data of dairy housing systems and to assess possibilities for reduction, based upon the analysis of processes and factors involved in the production and volatilization of ammonia. Mass balance methods for the determination of air exchange rates for naturally ventilated dairy cow buildings that are based upon natural or introduced tracers may have good potential for application in emission studies. Differences occur in housing systems, floor types and manure collection and manure storage systems. Ammonia emission levels for cubicle (loose) houses are higher (20-45 g/day/cow) than for tie stalls (5-27 g/day/cow), and variation in emissions by housing type is large. Integration of knowledge of ammonia emission related processes and factors will support a more detailed analysis of differences and variation, and will allow optimization of possibilities for emission reduction. Substantial emission reductions of up to 50% for cubicle houses with slatted floors can be achieved through each of the following measures: flushing of floors with water or diluted formaldehyde, optimised feeding strategies, and slurry acidification. Highest reductions are possible through V-shaped, solid floors (52%) as a single measure, or in combination with flushing with water (65%) or diluted formaldehyde (80%). Providing that drawbacks are solved, nationwide introduction of one or more these measures will lead to a maximal reduction of the NH3 emission in the Netherlands to 18 kt per year.