Title: Grazing: the whole picture Author
Submitted to: Trade Journal Publication
Publication Type: Trade Journal
Publication Acceptance Date: May 26, 2011
Publication Date: January 27, 2012
Citation: Rotz, C.A. 2012. Grazing: the whole picture. Hoard's Dairyman. 157(1):10. Interpretive Summary: An interpretive summary is not required.
Technical Abstract: Environmental concerns for our farms include nutrient leaching to ground water, runoff in surface water, gaseous emissions, and the carbon footprint of our production systems. Recent reports have labeled grazing-based dairies as less environmentally sustainable compared to year around confinement systems. These reports have not been comprehensive in their evaluation though, and perhaps biased by their goal. The carbon footprints of grazing and confinement type production systems vary considerably with the management practices used, so a decisive comparison of footprints is not possible. We find that the carbon footprints of grazing-based systems vary from somewhat less to greater than that of confinement systems where the comparison is greatly influenced by the fat-corrected milk produced by each. During the transition to perennial pasture, carbon sequestration in the soil can reduce the footprint of grazing systems below that of confinement systems. The use of well managed rotational grazing practices generally increase nitrate leaching to groundwater and reduce erosion and sediment bound phosphorus loss. Dissolved nutrient losses in runoff may be increased, but these losses should remain below that from cropping systems where manure remains on the soil surface. Ammonia, hydrogen sulfide, and VOC emissions should all be reduced per unit of milk produced. All dairy production systems have both positive and negative environmental effects when compared to others. With all factors considered, grazing-based dairy production systems should not be viewed as less environmentally sustainable compared to higher producing year around confinement systems. Let’s not pass the blame, and let’s all work together to improve the economic and environmental sustainability of our dairy industry.