Abstract
Air impurities, mainly ammonia, were studied in cage- and floor-laying poultry houses. Ammonia caused hygienic problems because insufficient ventilation, especially in winter. The effects of different litter materials on ammonia levels were first assessed in the laboratory. The materials that performed best in the laboratory were tested in three cage-laying and three floor-laying houses. According to laboratory tests, peat, superphosphate, and Stalosan were the best materials. Vermiculite and Enso® bark, made of pine bark and need also were tested in poultry houses. Average ammonia concentrations were 24.6 ppm in cage-laying houses and 44.2 ppm in floor-laying hour without the use of litter. Peat was the best litter in preventing ammonia release from the manure, the major source of ammonia vapor. P diminished the airborne ammonia by 62%, and the reduction in ammonia concentration was statistically significant in two poultry houses p<0.001 and p<0.01). Superphosphate lowered the ammonia level by 20%, which was not statistically significant. Vermiculite lowered 28% and Enso bark maximally by 9%, diminutions which were not statistically significant. The ventilation rate varied from 2.1 to 13.0 m3/hr. The air concentration of ammonia correlated poorly with the ventilation rate according to the linear regression analysis. The carbon dioxide concentration showed a high correlation with the ammonia concentration. The ammonia concentrations were high compared to the TLV® stressing the need for use of litter in order to reduce ammonia levels in poultry houses.