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Conference paper, 2007

Förbättrad luftkvalitet för värphöns i lågbeläggningssystem

von, Wachenfelt Hans


A field investigation of laying hens on floors was carried out including 18 randomly chosen hen-houses in southern and central parts of Sweden. The object was to assess knowledge of existing laying hen floor systems in regard to climate and indoor environment. Of the total floor area the manure pit and straw bedding areas varied between 80-95 %. As bedding material, 70 % of the producers used wood shavings, the others used straw or in some cases a mixture of shavings, straw and sand. The surfaces of the manure pits were equipped with waterlines and nipples, feed was supplied through a circular chain trough. In the studied hen-houses the average manure pit area was ca 50 % of the total floor area. Thirty-nine per cent of the hen-houses had their manure pits daily cleaned by manure conveyors in the bottom of the pits, the remaining hen-houses only cleaned out the manure when the hens had left the building. None of those with a manure removal system had a manure gas evacuation fan or a stop valve in the culvert. Only two hen-houses used supplementary heating during the year and none was provided with a permanent heating system. The results from the studied hen-houses indicate that with regular manure removal the levels of NH3-concentrations fell below 30 ppm at the designed outdoor temperature in winter time. The majority of the hen-houses with permanent manure storage inside the house had levels of NH3-concentrations exceeding 50 ppm. One hen-house had NH3-concentrations that fell below the hygienic limit no matter what time of the year. Identified factors that affected NH3-concentration were manure removal and ventilation systems

Published in

Book title: Ammonia emissions in agriculture
ISBN: 978-90-8686-029-6
Publisher: Wageningen Academic Publishers, P.O. Box 220, NL-6700 AE Wageningen, The Netherlands


International Conference on Ammonia in Agriculture: Policy, Science, Control and Implentation

    SLU Authors

    • Von Wachenfelt, Hans

      • Department of Rural Buildings and Animal Husbandry [LBT], Swedish University of Agricultural Sciences

    UKÄ Subject classification

    Agricultural Science

    Permanent link to this page (URI)