The Air Quality in Transylvanian Dairy Barns with Tie-Stalls

The aim of this work was to assess the quality of the air in dairy barns with tie-stalls, based on the total numberof mesophilic bacteria and on the concentrations of noxious gases (ammonia, carbon dioxide and hydrogen sulphide).We also studied the correlations between the main indicators of the air quality and the parameters of the microclimate(temperature, relative humidity and air flow velocity). Forty dairy cow barns were investigated in Transylvania in thecold season. The parameters were tested using specific methods. The numbers of the total mesophilic bacteria in the airvaried between 2.50 x 104 cfu/m3 and 3.36 x 105 cfu/m3, with a main value of 1.52 x 105 cfu/m3. The ammonia waspresent in all of the barns, having concentrations from 3.00 ppm to 37.00 ppm, with a mean value of 22.47 ppm.Ammonia exceeded the threshold limit in 57.5% of the investigated barns. The carbon dioxide was below the thresholdlimit in all of the barns and no hydrogen sulphide was found. Positive correlations were demonstrated between theammonia concentration and the air temperature (Spearman r = 0.451, p <0.05) and between the ammonia and therelative humidity of the air (Spearman r = 0.634, p <0.05). The air quality was low in more than a half of theinvestigated barns due the high concentration of the ammonia.