The environmental impact of dairy production: 1944 compared with 2007 (original) (raw)
Related papers
Dairy production: 1940's through today
2010
The sustainability of the US dairy industry is an increasingly significant issue. Producers are challenged with increasing the supply of dairy products to meet the demands of the growing population, whilst maintaining the tradition of environmental stewardship. Advances in nutrition, management, and genetics resulted in a fourfold improvement in dairy cow milk yield between 1944 and 2007. This allowed the US dairy industry to produce 59% more milk using 64% fewer cows and conferred considerable reductions in feed (77%), land (90%), and water (65%) use per gallon of milk. The carbon footprint of the entire US dairy industry was reduced by 41 % over the same time period. The global livestock industry is thought to contribute 18% of greenhouse gases worldwide. However, this global average does not address the variability between systems. Instead, differences in system productivity demonstrate the considerable variation in potential environmental impact between dairy regions. Improving productivity arguably has the greatest potential to reduce the environmental impact of dairy production, regardless of system characteristics. As dairy industries worldwide pledge to reduce total greenhouse gas emissions, attention should be focused on a whole-system life cycle assessment approach rather than racing to find a 'magic bullet' solution focused at a specific process that may confer negative trade-offs.
2010
The sustainability of the US dairy industry is an increasingly significant issue. Producers are challenged with increasing the supply of dairy products to meet the demands of the growing population, whilst maintaining the tradition of environmental stewardship. Advances in nutrition, management, and genetics resulted in a fourfold improvement in dairy cow milk yield between 1944 and 2007. This allowed the US dairy industry to produce 59% more milk using 64% fewer cows and conferred considerable reductions in feed (77%), land (90%), and water (65%) use per gallon of milk. The carbon footprint of the entire US dairy industry was reduced by 41 % over the same time period. The global livestock industry is thought to contribute 18% of greenhouse gases worldwide. However, this global average does not address the variability between systems. Instead, differences in system productivity demonstrate the considerable variation in potential environmental impact between dairy regions. Improving productivity arguably has the greatest potential to reduce the environmental impact of dairy production, regardless of system characteristics. As dairy industries worldwide pledge to reduce total greenhouse gas emissions, attention should be focused on a whole-system life cycle assessment approach rather than racing to find a 'magic bullet' solution focused at a specific process that may confer negative trade-offs.
Journal of Dairy Science, 2014
Life-cycle assessment (LCA) is the preferred methodology to assess carbon footprint per unit of milk. The objective of this case study was to apply an LCA method to compare carbon footprints of high-performance confinement and grass-based dairy farms. Physical performance data from research herds were used to quantify carbon footprints of a high-performance Irish grass-based dairy system and a top-performing United Kingdom (UK) confinement dairy system. For the US confinement dairy system, data from the top 5% of herds of a national database were used. Life-cycle assessment was applied using the same dairy farm greenhouse gas (GHG) model for all dairy systems. The model estimated all on-and off-farm GHG sources associated with dairy production until milk is sold from the farm in kilograms of carbon dioxide equivalents (CO 2 -eq) and allocated emissions between milk and meat. The carbon footprint of milk was calculated by expressing GHG emissions attributed to milk per tonne of energycorrected milk (ECM). The comparison showed that when GHG emissions were only attributed to milk, the carbon footprint of milk from the Irish grass-based system (837 kg of CO 2 -eq/t of ECM) was 5% lower than the UK confinement system (884 kg of CO 2 -eq/t of ECM) and 7% lower than the US confinement system (898 kg of CO 2 -eq/t of ECM). However, without grassland carbon sequestration, the grass-based and confinement dairy systems had similar carbon footprints per tonne of ECM. Emission algorithms and allocation of GHG emissions between milk and meat also affected the relative difference and order of dairy system carbon footprints. For instance, depending on the method chosen to allocate emissions between milk and meat, the relative difference between the carbon footprints of grass-based and confinement dairy systems varied by 3 to 22%. This indicates that further harmonization of several aspects of the LCA methodology is required to compare carbon footprints of contrasting dairy systems. In comparison to recent reports that assess the carbon footprint of milk from average Irish, UK, and US dairy systems, this case study indicates that top-performing herds of the respective nations have carbon footprints 27 to 32% lower than average dairy systems. Although differences between studies are partly explained by methodological inconsistency, the comparison suggests that potential exists to reduce the carbon footprint of milk in each of the nations by implementing practices that improve productivity.
The Relationship Between Cow Production and Environmental Impact
Take Home Message • US dairy industry sustainability is increasingly important as producers are challenged with increasing dairy product supply to meet the demands of the growing population, while maintaining the tradition of environmental stewardship • Advances in nutrition, management and genetics resulted in a four-fold improvement in milk yield between 1944 and 2007. This allowed the US dairy industry to produce 59% more milk using 64% fewer cows and conferred considerable reductions in feed (77%), land (90%) and water (65%) use per gallon of milk. The carbon footprint of the entire US dairy industry was reduced by 41% over the same period. • The global livestock industry is thought to contribute 18% of greenhouse gases worldwide. However, this global average does not address variability between systems. Differences in system productivity demonstrate the considerable variation in environmental impact between dairy regions. • As dairy industries worldwide pledge to reduce total greenhouse gases emissions, attention should be focused on a whole-system approach rather than a ‘magic bullet’ solution that may confer negative trade-offs. • Improving productivity has the greatest potential to reduce the environmental impact of dairy production, regardless of system characteristics.
2011
Take Home M essage US dairy industry sustainability is increasingly important as producers are challenged with increasing dairy product supply to meet the demands of the growing population, while maintaining the tradition of environmental stewardship Advances in nutrition, management and genetics resulted in a four-fold improvement in milk yield between 1944 and 2007. This allowed the US dairy industry to produce 59% more milk using 64% fewer cows and conferred considerable reductions in feed (77%), land (90%) and water (65%) use per gallon of milk. The carbon footprint of the entire US dairy industry was reduced by 41% over the same period. The global livestock industry is thought to contribute 18% of greenhouse gases worldwide. However, this global average does not address variability between systems. Differences in system productivity demonstrate the considerable variation in environmental impact between dairy regions. As dairy industries worldwide pledge to reduce total greenhouse gases emissions, attention should be focused on a wholeconfer negative trade-offs. Improving productivity has the greatest potential to reduce the environmental impact of dairy production, regardless of system characteristics.
Regional carbon footprint analysis of dairy feeds for milk production in the USA
Purpose A greenhouse gas emissions analysis (carbon footprint) was conducted for cultivation, harvesting, and production of common dairy feeds used for the production of dairy milk in the USA. The goal was to determine the carbon footprint (grams CO 2 equivalents (gCO 2 e)/kg of dry feed) in the USA on a regional basis, identify key inputs, and make recommendations for emissions reduction. Methods Commonly used dairy feeds in the USA, such as soybeans, alfalfa, corn, and others, were identified based on a recent literature review and information from dairy farm surveys. The following input data for the cultivation and harvesting of dairy feeds were collected for five US regions: crop production data, energy input, soil amendments, and crop protection chemicals. Life cycle inventory input data were mainly collected from the US Department of Agriculture National Agricultural Statistical Service on a state-bystate basis as well as from state extension services forage crop budget estimates. In addition to consulting other life cycle assessment studies and published articles and reports, this cradle-to-farm gate carbon footprint analysis was conducted using the Ecoinvent™ unit processes in SimaPro version 7.1© (PRé Consultants 2009). Results The final carbon footprint results (gCO 2 e/kg of dry dairy feed) varied regionally depending on a number of factors such as lime and fertilizer application rates. The average national US carbon footprint results of the main feeds were: corn grain (390), corn silage , dried distillers grains with solubles (910 dry mill, 670 wet mill), oats (850), soybeans (390), soybean meal (410), winter wheat (430), alfalfa hay (170), and forage mix (160).
The carbon footprint of dairy production systems through partial life cycle assessment
Journal of dairy science, 2010
Greenhouse gas (GHG) emissions and their potential effect on the environment has become an important national and international issue. Dairy production, along with all other types of animal agriculture, is a recognized source of GHG emissions, but little information exists on the net emissions from dairy farms. Component models for predicting all important sources and sinks of CH 4 , N 2 O, and CO 2 from primary and secondary sources in dairy production were integrated in a software tool called the Dairy Greenhouse Gas model, or DairyGHG. This tool calculates the carbon footprint of a dairy production system as the net exchange of all GHG in CO 2 equivalent units per unit of energy-corrected milk produced. Primary emission sources include enteric fermentation, manure, cropland used in feed production, and the combustion of fuel in machinery used to produce feed and handle manure. Secondary emissions are those occurring during the production of resources used on the farm, which can include fuel, electricity, machinery, fertilizer, pesticides, plastic, and purchased replacement animals. A longterm C balance is assumed for the production system, which does not account for potential depletion or sequestration of soil carbon. An evaluation of dairy farms of various sizes and production strategies gave carbon footprints of 0.37 to 0.69 kg of CO 2 equivalent units/ kg of energy-corrected milk, depending upon milk production level and the feeding and manure handling strategies used. In a comparison with previous studies, DairyGHG predicted C footprints similar to those reported when similar assumptions were made for feeding strategy, milk production, allocation method between milk and animal coproducts, and sources of CO 2 and secondary emissions. DairyGHG provides a relatively simple tool for evaluating management effects on net GHG emissions and the overall carbon footprint of dairy production systems. Figure 1. Primary and secondary emission sources and sinks for a partial life cycle assessment of the carbon footprint of dairy production systems.