Ammonia emission from four systems for group-housed sows

In The Netherlands in the 1990's many housing systems with low ammonia emission for individual housed dry and pregnant sows were developed. Because of welfare regulations dry and pregnant sows must be housed in a group since 1998 for new and remodeled buildings and for all buildings in 2008. Regulation for ammonia emission is requiring that only housing systems with a maximum ammonia emission of 2.6 kg of NH3 per sow place per year can be used. Four new housing systems for group-housed sows were developed which are simple, flexible and use concrete slats. The systems were: System A: Sloped pit walls with an integrated cooling system and concrete slats System B: Prefabricated manure trays with concrete slats System C: Sloped pit walls with concrete slats System D: Sloped pit walls with concrete and metal slats The objective of this research was to determine the ammonia emission from these four systems. Average ammonia emission from systems A, B, C and D were 4.5, 4.0, 3.6 and 3.2 kg of NH3 per sow place per year, respectively. Ammonia emission from all four systems for group-housed sows exceeded the maximum ammonia level of 2.6 kg of NH3 per sow place per year. But systems B, C and D reduced the ammonia emission with 5, 14 and 24%, respectively, compared with traditional individual stalls.