Exploring implications of new EU legislation for animal welfare and of trends in organic farming on ammonia emissions

Animal welfare legislation in the EU, i.e., the EU Directives for the protection of farm animals coming into force by 2013 the latest, and the EU Regulation on organic farming might lead to an increase in ammonia (NH3) emissions. A review of the available, although rather limited, literature reveals that animal-friendly housings systems, in line with welfare legislation, are not ammonia-neutral compared to the conventional housing systems. NH3 emissions per pig from animal-friendly pig houses vary considerably. Emissions from houses that comply with the EU directives differ between -25 percent and +50 percent, while emissions from organic pig houses range from about -10 percent to +170 percent compared to the reference values for conventional houses. The main reason for higher emissions is associated with additional outdoor area required in organic farming. Careful design of housing area and appropriate management can lead to lower emissions than in conventional systems. NH3 emissions from animal-friendly aviary systems for laying hens were around threefold the emission per hen from battery cages. For organic cattle, emissions from housing are about 50 percent higher than from conventionally kept cattle. The impact of increased penetration of animal-friendly houses and organic farming on NH3 emissions was analyzed with the GAINS model. We have developed two scenarios using low and high emission factors and applied them to the recent national agricultural projections for 2020. For EU-27, we calculate that such a development could lead to a slight decrease or to an increase of NH3 emissions by around five percent by 2020, compared to baseline scenario. However, larger variations occur for specific animal types and countries. An increase in emissions would counteract the EU air pollution policy that calls for a reduction of NH3 emissions by 27 percent in 2020, compared to the 2000 level. Bearing that in mind, development in animal housing systems and their impacts on NH3 emissions need to be analyzed further with more field studies and measurements.