Gas emissions from dairy cow and fattening pig buildings : effects of animal parameters, climatic factors and manure management on methane and ammonia missions
Abstract: The objective of this research is to contribute to the knowledge concerning the abatement of gas emissions from livestock production. Investigations regarding the choice of sampling locations for gas concentration measurements, quantification of gas emissions and the factors that affect gas emissions were conducted. NH₃, CH₄, CO₂ and N₂O emissions were measured from two naturally ventilated buildings for dairy cows and from a mechanically ventilated building for fattening pigs. Animal activity, temperature and humidity were also measured. Gas and odour emissions from manure samples with and without the addition of wood shavings were measured in a flux chamber at different air and manure temperatures. Significant differences existed in the mean concentrations of all the gases at various indoor sampling locations in a naturally ventilated building for dairy cows. The differences in gas concentrations between various sampling locations were much smaller for long-term, relative to short-term, measurements, suggesting that a single sampling location during long-term measurements may generate representative data. Decreasing daily animal activity was associated with increasing pig weight, and with increasing air temperatures for the cows. Diurnal variations in gas emissions were related to feeding/cleaning routines and to animal activity. Daily emissions from the pig building increased with pig weight and temperature. Air temperature was more important than cow activity for daily NH₃ emissions while cow activity was more important than air temperatures for daily CH₄ emissions. Reducing manure temperatures and increasing manure carbon-to-nitrogen ratio are potential NH₃ abatement techniques. However, low air temperatures may increase cow activity which may in turn increase CH₄ emissions. Increasing the frequency of manure removal from the floor and from animal buildings reduces indoor emissions of most gases. Low N₂O emissions were measured from the buildings in this study; hence the use of liquid manure systems might reduce N₂O emissions.
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