Statistical Modeling of Airborne Bacteria and Endotoxins Concentrations in Australian Piggery Buildings

摘要

The concentrations of total airborne bacteria and respirable endotoxins were monitored in 160 piggery buildings in four states of Australia (Queensland, Victoria, Western and South Australia) between autumn 1997 and autumn 1999. The characteristics ofthe buildings and management systems used were documented at the time of sampling to identify the roles of these factors in contributing to airborne bacteria and endotoxin concentrations. The overall mean airborne bacteria concentration was 1.17 x 105 cfu/m3 and a mean internal concentration of 33.1 EU/m3 was measured for respirable endotoxins. In contrast to husbandry systems with no bedding material (median range of 0.68-0.90 x 105 cfu/m3), the deep-bedded shelters had a least squares median concentration for airborne bacteria of 2.17 x 105 cfu/m3 and endotoxin of 76.3 EU/m~3. These endotoxin and airborne bacteria concentrations exceed exposure limits recommended in Australia and therefore could potentially compromise the health of animals and humans working in the buildings. In addition to the building type affect on both pollutants, endotoxin concentrations positively correlated with increased humidity and airborne bacteria concentrations increased as the level of pen hygiene decreased. These findings will aid the development of strategies for the industry, such as improved cleaning, to improve air quality in pig buildings and in the environment, improving health and welfare of both pigs and piggery staff.