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Gas emissions from livestock are subject to strong diurnal and short term fluctuations, which cause several emission peaks over the day. One main influencing factor is the variation of the ventilation rate, which commonly is mainly temperature controlled in mechanically ventilated livestock buildings. Concluding from known relations between the emissions and ventilation, a possibility is seen to reduce the mean gas emissions from a pig house by cutting emission peaks which occur because of animal activity, feeding and day-night rhythms. In the scope of a research project at a pig facility special emphasise is laid on the development and test of several innovative ventilation control systems which go hand in hand with a verifiable emission reduction and an animal acceptable indoor air quality.

The test of different ventilation control strategies will be carried out over four successive 16 weeks fattening periods at two spatially separated compartments. A previous fattening period served to adapt and check the measuring methods as well as the newly developed ventilation control software and hardware devices as part of preliminary investigations.

Both compartments are subdivided into two large pens with 27 pigs per pen, featuring concrete floor half fully slatted (slot share 14%) and half with a reduced slot share of 6%. The mechanical ventilation is designed as underfloor extraction with fresh air supply through pore channels. The measuring system allows the continuous registration of gas concentrations, ventilation rates, temperatures, humiditys, and the animal activity.

Three ventilation control strategies will be compared with a conventional temperature controlled ventilation as reference. The ventilation control strategies to be tested feature different direct or indirect methods to adjust or limit the ventilation rate by means of temperature, gas concentrations (e.g. CO2), a slowed down response time of the ventilation, cooling the air by water fogging, and consideration of the animal activity and feeding strategy.

After the first completed fattening periods in spring 2003 results for assessing the mode of operation and effectiveness of the different ventilation control strategies will be available. (Download PDF)    (Export to EndNotes)