Two-thirds of laying hens in the Netherlands were housed in so-called low-emission sheds in 2008. The emission of ammonia in these sheds complies with legal requirements which are to come into effect on 1 January 2010. Most meat chickens, porkers, and sows were still housed in facilities where too much ammonia is emitted.
Animal housing order
A government order came into effect on 1 April 2008 under which all pig and poultry sheds are required to have low-emission systems by 1 January 2010. This means that provisions must be in place to limit the emission of ammonia.
In pig sheds, ammonia emissions are usually reduced by making adaptations to the flooring or slurry pits. Air scrubbers are only used in 10 to 15 percent of animal sheds. In poultry farming emission reduction systems are integrated in the buildings.
Housing of meat chickens and laying hens, 2008
Laying hens in particular in low-emission sheds
Systems to reduce ammonia emissions are mostly applied in sheds for laying hens. In 2008, 40 percent of laying hens were housed in low-emissions battery systems, just over 25 percent in low-emission free-range sheds. Battery systems will be banned from 1 January 2012. From then on, all laying hens must be able to move around in free-range sheds.
Only 20 percent of meat chickens are housed in low-emission sheds. Low-emission sheds which comply with the strict norms in the Netherlands have not been available for very long.
Housing of porkers and dairy cows, 2008
Ammonia emissions in dairy farming remain high
Although the share of ammonia emission accounted for by dairy cattle kept indoors is large, only 5 percent of cows are kept in low-emission sheds; these buildings are not good for animal welfare and are therefore hardly used at all. Traditional loose house facilities will still be allowed for the time being. Farmers who build new loose house barns are obliged to put the cows out to pasture in the summer.
Total ammonia emissions from animals kept indoors comes to about 63 million kg per year. This is nearly half of total ammonia emissions in the Netherlands, and more than half of emissions by agriculture.
Cor van Bruggen and Kees Olsthoorn