There is a need for technical solutions to reduce the concentrations of bioaerosols in the air and in the exhaust air of livestock buildings. A prototype of an air washer combined with a UV-irradiation system was positioned in a commercial pig fattening unit to test its efficiency of reducing culturable airborne microorganisms. No significant reduction in airborne bacteria and fungi was observed when untreated air passed through the device. However, when the air washer or the UV-irradiation system was activated, the concentrations of mesophilic aerobic bacteria, methicillin resistant Staphylococcus aureus and mesophilic aerotolerant cocci were reduced significantly (p < 0.01). Washing the air reduced bacteria by 84 to 96% and the relative reduction due to UV-irradiation ranged between 55 and 90%. The highest relative reduction in airborne bacteria (90 to 99%) was detected when the air washer and the UV-irradiation systems were in simultaneous operation. The concentration of total airborne fungi was reduced significantly (p < 0.05) only when the air was washed and UV-irradiated. Although these preliminary results provided significant and comprehensible findings, long-term studies are required to assess the efficiency of the device in more detail.The combination of air washing and UV-irradiation seem to be a useful technique for abating airborne microorganisms within or emitting from piggery buildings. However, some technical problems remain, such as the deposition of particulate matter on the surface of UV-irradiators and the consumption of fresh water by the air washer. These issues must be resolved before the system may be implemented for general practice.

The available floor space has a strong impact on the execution of various behaviours of laying hens. Presently, in Germany detailed requirements on the housing of pullets are insufficient. In order to get a first approximation, the floor space covered by pullets was determined by the colour contrast planimetric method KobaPlan. The measurements on standing and sitting pullets were done on a random sample of Lohmann Brown (LB), Lohmann Tradition (LT), Lohmann Selected Leghorn (LSL) and Dekalb White (DW) hybrids from the 6th week of life to 18/20 weeks at regular intervals. The hens were weighed and photographed digitally in a specific planimetric box (n = 2600 photographs from pullets in standing and 1360 in sitting position). Afterwards the KobaPlan software program calculated the animal area. The results showed a correlation between floor space covered by the pullets in standing position and the live weight (R-2 = 0.80-0.96). The mean floor space covered by LB and LT at the end of rearing (body weight 1450 +/- 25 g LB and 1500 +/- 25 g LT) was 422.4 +/- 41.9 cm(2) (LB) and 446.7 +/- 49.0 cm(2) (LT) standing, respectively 448.0 +/- 51.0 cm(2) (LB) and 464.5 +/- 42.6 cm(2) (LT) sitting. LSL and DW (body weight 1300 +/- 25 g) used 371.0 +/- 41.3 cm(2) (LSL) and 349.3 +/- 26.3 cm(2) (DW), respectively in standing and 379.5 +/- 41.2 cm(2) (LSL) in sitting position. Maximum stocking density recommendation for pullets based on these planimetric results compared with the space allowance in alternative housing systems for laying hens are between eleven and 14 birds/m(2). To verify this stocking density recommendation for pullets further studies should be complemented by specific ethological observations.

"Livestock-associated" Methicillin-resistent Staphylococcus aureus (LA-MRSA) are frequently found in the air of piggeries, are emitted into the ambient air of the piggeries and may also drift into residential areas or surrounding animal husbandries.. In order to reduce emissions from animal houses such as odour, gases and dust different biological air cleaning systems are commercially available. In this study the retention efficiencies for the culturable LA-MRSA of a bio-trickling filter and a combined three step system, both installed at two different piggeries, were investigated. Raw gas concentrations for LA-MRSA of 2.1 x 10(2) cfu/m(3) (bio-trickling filter) and 3.9 x 10(2) cfu/m(3) (three step system) were found. The clean gas concentrations were in each case approximately one power of ten lower. Both systems were able to reduce the number of investigated bacteria in the air of piggeries on average about 90%. The investigated systems can contribute to protect nearby residents. However, considerable fluctuations of the emissions can occur.

For effective sampling of airborne micro-organisms different techniques such as impingement, filtration and impaction are commonly used. Impaction is the method which allows best for direct collection on adhesive surfaces for immediate microscopic analysis. The efficiency of collection largely depends on the quality of the sampling surface to retain particles. This article compares the suitability of some traditional and new adhesive coatings to collect and retain airborne micro-organisms efficiently for subsequent fluorescence microscopy. Sacharomyces cerevisiae yeast cells were aerosolized in a test tubing system in the laboratory. Samples were collected by a round jet impactor in a defined round deposition area on glass slides coated with different adhesive materials. Particle distribution in the deposition area and collection efficiency as well as particle losses were estimated. Fluorescent staining with Mycoval and DAPI was used to quantify the amount of collected cells and cell losses due to the staining procedure. Filtration was taken as reference system. The collection efficiency of the tested adhesive surfaces ranged from 2 to 97%. Silicone sealants showed with 97% the highest collection efficiency. All particles were located in the central region of the deposition area. Cell losses due to the staining procedure were very small (<1%) and no background fluorescence was observed after DAPI staining. Even after sampling times of 45 min the collection efficiency was still above 90%. Longer collection (>50 min) resulted in increasing cell losses. Collection efficiency was little influenced by relative humidity of the air between 20% and 100%.