|Rotz, Clarence - Al|
Submitted to: Dairy Herd Management Symposium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 11/2/2011
Publication Date: 11/7/2011
Citation: Risse, L.M., Belflower, J.B., Rotz, C.A., Kiepper, B., Benard, J. 2011. A case study comparing the environmental impacts of grazing and confined dairies. Dairy Herd Management Symposium Proceedings, November 1-2, 2011, Tifton, Georgia. 2011 CDROM. Interpretive Summary: An interpretive summary is not required.
Technical Abstract: Two actual dairy farms in Georgia were simulated using the Integrated Farm System Model (IFSM). Comparing the model’s outputs to the actual farm performance verified the ability of the model to assess conditions in this region. Further simulations assessed the environmental impacts of these production systems. The carbon footprints of the milk produced by the two farms were similar with the footprint of the pasture-based system about 4% greater than that of the confinement system. However when potential soil carbon sequestration was considered, the carbon footprint of the pasture-based dairy was about 10% less than that of the confinement dairy. Erosion and phosphorus runoff were much greater on the confined dairy because of the high clay content in the soil and the large area of land tilled each year to produce annual crops. Nitrate leaching was greater on the pasture-based dairy because of the coarser soil texture and because urine and feces deposits on pasture created high nitrogen concentrations on small land areas. Ammonia volatilization was greater from the manure on barn floors, during storage, and following land application on the confined dairy. Annually, the confined dairy used 6.0 gallons of water per pound of energy corrected milk produced and 0.047 kWh of energy per pound of energy corrected milk produced. The pasture-based dairy used 15.8 gallons of water and 0.048 kWh of energy per pound of energy corrected milk. Because different land bases were used for the two dairy farms, this analysis was not intended to provide a comprehensive comparison of pasture-based and confinement fed dairy production systems, but rather a comparison of representative dairy farms of the region. The IFSM provided a valuable tool for evaluating the environmental impact of dairy farms in the southeastern United States; even though, it could not fully represent the triple cropping practices sometimes used in this region. An examination of how management changes affected water and energy use and predicted nutrient losses gives farm managers guidance on how management of their farms can affect the environment.