Concentration of noxious gases in dairy, beef and veal calves farms in Northern Italy
Aim of this paper was investigating carbon dioxide and ammonia concentrations through a cross-sectional study applied during winter 2007 in 35 dairy cattle, 21 beef cattle and 30 veal calves farms located in North-eastern Italy. Repeated instrumental gas measurements were carried out in the feeding alley and in the resting area. Regardless of the measure point, gases concentrations in the three categories of cattle did not give reason for concern since average values were below the threshold limit set for animals. Significant difference (P<0.05) were observed among cattle categories with the worse air quality detected in veal calves farms. Twenty percent of these farms had at least one ammonia measure exceeding the recommended level of 10 ppm. Carbon dioxide was higher (P<0.001) in closed barns compared to open barns for both, dairy and beef cattle indicating a worse ventilation efficiency. Within closed barns tethered compared to loosed housed cows showed higher carbon dioxide concentrations. Similar results were found for beef cattle on fully slatted floors compared to bulls on deep litter. These results should drive attention towards specific management practices and facilities but, in order to obtain a full picture on the levels of gases concentration in cattle farms, further research should consider their emissions in different seasons as well as cattle age, breed, and productive level.