Agroscope Reckenholz-Tänikon Research Station ART, CH-8356 Ettenhausen

Odour concentration and emission from dairy cattle housing with an exercise yard

Local authorities, government agencies and courts are increasingly faced with complaints and lawsuits relating to odour annoyance from livestock housing systems. Odour concentration and emission from five naturally ventilated dairy cattle sheds were compared in two seasons and at two times of day. A newly developed tracer ratio method was used for these cowsheds with cubicles, solid floor surfaces and an adjacent exercise yard. Test subjects were used to determine on the olfactometer the odour concentration from area sources on the ground (cubicle, traffic alley and exercise yard) and at a height of 3 m. Whereas at ground level the highest odour concentrations occurred mainly in the traffic alley, the odour concentration at a height of 3 m was comparable over the three area sources. This would indicate that at a height of 3 m there had already been considerable intermixture between these areas. On six of the seven measurement days, odour emission in the afternoon was two to four times higher than in the morning. The variation in odour emission between farms was also high. A comparative assessment of animal housing systems therefore requires broadly supported data on several farms, the inclusion of all seasons and high time-of-day resolution. In order to provide solutions for odour reduction, there is a need for well-founded, up-to-date planning data to determine minimum distances; these data will be used as a basis for extension modelling and the most important variables influencing odour release.

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