Ammonia emissions from pig houses in The Netherlands, Denmark and France

In recent decades pig production has been intensified in most European countries. This has resulted in a surplus of manure and a serious concern about the effect of ammonia emissions on environmental acidification and the pollution of ground and surface water. In The Netherlands, Denmark and France approximately 50% of the ammonia emissions from pig production is from pig housing and slurry storage. Ammonia emissions from pig houses can be reduced by: (1) lowering the concentrations of urea and ammonia in the slurry; (2) lowering the temperature of the slurry; (3) reducing the emitting surface area; (4) reducing the pH of the slurry. Various housing techniques have been developed to reduce ammonia emissions. Most of these techniques are costly but cheaper systems are becoming available. A combination of housing and feeding measures seems most promising to achieve a substantial reduction in ammonia emissions at relatively low costs. Lowering the protein content of the diet, including non-starch polysaccharides and adding acidifying salts instead of CaCO3 are the main possibilities at the moment to reduce the ammonia emission by dietary means. (C) 1999 Elsevier Science B.V. All rights reserved.