Environmental assessment of United States dairy farms

Authors: Rotz, Clarence - Al; Stout, Robert; Leytem, April; Feyereisen, Gary; Waldrip, Heidi; THOMA, GREG - University Of Arkansas; HOLLY, MICHAEL - University Of Wisconsin; Bjorneberg, David - Dave; Baker, John; Vadas, Peter; Kleinman, Peter

Submitted to: American Dairy Science Association Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 4/6/2021
Publication Date: 7/11/2021
Citation: Rotz, C.A., Stout, R.C., Leytem, A.B., Feyereisen, G.W., Waldrip, H., Thoma, G., Holly, M., Bjorneberg, D.L., Baker, J.M., Vadas, P.A., Kleinman, P.J. 2021. Environmental assessment of United States dairy farms[abstract]. American Dairy Science Association Abstracts. P.1.

Interpretive Summary: No Interpretive Summary is not required for this Abstract Only. JLB.

Technical Abstract: Dairy farms in the United States are diverse and although regional dairy production and farm strategy has been evaluated for environmental impact, a comprehensive national assessment is important to define national priorities for sustainable intensification. We estimated important environmental footprints of dairy farm production using process-level simulation and cradle-to-farm gate life cycle assessment. Dairy farms representing the sizes and management practices found in six regions were simulated with the Integrated Farm System Model (IFSM). Regional and national environmental footprints were determined as an average of all simulated farms weighted by the portion of milk each contributed to the total. Nationally, dairy farms were assessed to emit 99,000 ± 8,480 Gg CO2e of greenhouse gas, equivalent to 1.5% of the estimated U.S. total greenhouse gas emission, with a commodity-based intensity of 1.01 ± 0.09 kg CO2e/kg of fat and protein corrected milk (FPCM) produced. Fossil energy consumption was 242,700 ± 38,400 TJ, 0.3% of the U.S. total, or 2.48 ± 0.39 MJ/kg FPCM. Blue (non-precipitation) water consumption was 11,600 ± 2,480 Tg, roughly 3.0% of the estimated U.S. total freshwater use, with an intensity of 119 ± 25 kg/kg FPCM. While these environmental footprints represent a relatively small portion of their respective national inventories, the dairy industry’s contribution to reactive nitrogen (N) losses appears to be considerably greater. Losses of reactive N were estimated at 970 ± 133 Gg, with an intensity of 9.92 ± 1.36 g/kg FPCM. Although there are no national estimates of total reactive N emissions, dairy farms were found to contribute 19 – 24% of national inventories of ammonia (NH3) emissions. While strategies are available to reduce NH3 emissions, finding economical and sustainable solutions that do not result in pollution swapping remains a challenge for the dairy industry.