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ARS Home » Midwest Area » Ames, Iowa » National Laboratory for Agriculture and The Environment » Agroecosystems Management Research » Research » Publications at this Location » Publication #201341
Title: Alcohol, volatile fatty acid, phenol, and methane emissions from dairy cows and fresh manure

Author
item SUN, HUAWEI - UNIVERSITY OF CALIFORNIA
item Trabue, Steven - Steve
item JACKSON, WENDI - UNIVERSITY OF CALIFORNIA
item Scoggin, Kenwood
item PAN, YUEE - UNIVERSITY OF CALIFORNIA
item ZHAO, YONGJING - UNIVERSITY OF CALIFORNIA
item MITLOEHER, FRANK - UNIVERSITY OF CALIFORNIA

Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/6/2007
Publication Date: 3/1/2008
Citation: Sun, H., Trabue, S.L., Jackson, W., Scoggin, K.D., Pan, Y., Zhao, Y., Mitloeher, F. 2008. Alcohol, volatile fatty acid, phenol, and methane emissions from dairy cows and fresh manure. Journal of Environmental Quality. 37:615-622.

Interpretive Summary: There are approximately 2.5 million dairy cows in California. Estimates for the emissions from dairy cows list their waste as the major source of regional air pollutants, which include both smog-forming volatile organic compounds (VOC) and greenhouse gases (GHG). However, actual data on emissions from dairy cows and their waste is sparse with most estimates based on extrapolated data. In this study, VOCs and GHGs emitted from both lactating and non-lactating (dry) dairy cows and their waste was monitored. The study was conducted in a controlled environmental chamber used to simulate commercial freestall cow housing conditions. High fluxes of methanol, ethanol, and methane were measured from dairy cows and their waste. The average methanol and ethanol fluxes were 2.89 and 4.47 kg/cow/yr for dry cows and their waste, respectively. The average methanol and ethanol fluxes were 6.14 and 11.13 kg/cow/yr for lactating cows and their waste, respectively. Both compounds increased over time coinciding with increase in the accumulated waste on the chamber floor. Volatile fatty acids and phenolic compounds were emitted at low levels. Average methane emissions were associated with enteric fermentation from cows rather than waste and were 108 and 160 kg/cow/yr for dry and lactating cows, respectively. Lactating cows produced significantly more gaseous emission of both VOC and GHG than dry cows. In summary, dairy cows and fresh waste have the potential to emit considerable amounts of alcohols and methane and research is needed to determine effective mitigation. Research results described in this report provides animal scientist, regulators, and atmospheric scientist valuable information on the emissions of VOCs and GHG produced from a typical dairy operation in California.

Technical Abstract: There are approximately 2.5 million dairy cows in California. Emission inventories list dairy cows and their waste as the major source of regional air pollutants, but data on their actual emissions remain sparse, particularly for smog-forming volatile organic compounds (VOC) and greenhouse gases (GHG). We report measurements of VOCs, especially alcohols, volatile fatty acids (VFAs), and phenols, as well as GHG (methane) emitted from non-lactating (dry) and lactating dairy cows and their waste under controlled conditions. The experiment was conducted in an environmental chamber that simulates commercial freestall cow housing conditions. High fluxes of methanol, ethanol, and methane were measured from cows and/or their fresh waste. The average methanol and ethanol emissions were 2.89 and 4.47 kg/cow/yr from dry cows and waste, and 6.14 and 11.13 kg/cow/yr from lactating cows and waste, respectively. Both alcohols increased over time coinciding with increasing accumulation of waste on the chamber floor. Volatile fatty acids and phenols were emitted at very low, hardly measurable emission rates. Average methane emissions were associated with enteric fermentation from cows rather than waste and were 108 and 160 kg/cow/yr for dry and lactating cows, respectively. Lactating cows produced considerably more gaseous VOC and GHG emissions than dry cows (P<0.001). Compared with GHG and alcohol emissions, the emissions of VFAs and phenol compounds from dairy cows and manure were close to the lower detection limit of both the assay and the instrumentation. The high variability across the three replicate cow groups with respect to VFAs and phenols and concentrations near the lower detection limit of the assay make further interpretation of tends difficult. In summary, dairy cows and fresh waste have the potential to emit considerable amounts of alcohols and methane and research is needed to determine effective mitigation.