Dairy Production (original) (raw)
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Productivity gains and greenhouse gas emissions intensity in dairy systems
Livestock Science, 2011
This paper explores the relationship between productivity of dairy production and greenhouse gas (GHG) emissions on a global scale. A Life Cycle Assessment (LCA) methodology was used to assess GHG emissions from dairy production and processing chains. Milk yield expressed as kg fat and protein corrected milk (FPCM) per animal was chosen as a proxy for system productivity. On a per cow basis, GHG emissions increase with higher yields. However, GHG emissions per kg FPCM decline substantially as animal productivity increases. The contribution of different gases to total GHG emissions of dairy production systems vary; methane and nitrous oxide emissions decrease with increasing productivity, while carbon dioxide emissions increase, but on a lower scale. Productivity increase therefore offers not only a pathway to satisfying increasing demand for milk but also a viable mitigation approach, especially in areas where milk yields are currently below 2000 kg/cow and year.
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.
The environmental impact of dairy production: 1944 compared with 2007
A common perception is that pasture based, low-input dairy systems characteristic of the 1940s were more conducive to environmental stewardship than modern milk production systems. The objective of this study was to compare the environmental impact of modern (2007) US dairy production with historical production practices as exemplified by the US dairy system in 1944. A deterministic model based on the metabolism and nutrient requirements of the dairy herd was used to estimate resource inputs and waste outputs per billion kg of milk. Both the modern and historical production systems were modeled using characteristic management practices, herd population dynamics, and production data from US dairy farms. Modern dairy practices require considerably fewer resources than dairying in 1944 with 21% of animals, 23% of feedstuffs, 35% of the water, and only 10% of the land required to produce the same 1 billion kg of milk. Waste outputs were similarly reduced, with modern dairy systems producing 24% of the manure, 43% of CH4, and 56% of N2O per billion kg of milk compared with equivalent milk from historical dairying. The carbon footprint per billion kilograms of milk produced in 2007 was 37% of equivalent milk production in 1944. To fulfill the increasing requirements of the US population for dairy products, it is essential to adopt management practices and technologies that improve productive efficiency, allowing milk production to be increased while reducing resource use and mitigating environmental impact.
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.
Contribution of milk production to global greenhouse gas emissions
Environmental Science and Pollution Research
Background, aim and scope Studies on the contribution of milk production to global greenhouse gas (GHG) emissions are rare (FAO 2010) and often based on crude data which do not appropriately reflect the heterogeneity of farming systems. This article estimates GHG emissions from milk production in different dairy regions of the world based on a harmonised farm data and assesses the contribution of milk production to global GHG emissions. Materials, methods and results The methodology comprises three elements: (1) the International Farm Comparison Network (IFCN) concept of typical farms and the related globally standardised dairy model farms representing 45 dairy regions in 38 countries; (2) a partial life cycle assessment model for estimating GHG emissions of the typical dairy farms; and (3) standard regression analysis to estimate GHG emissions from milk production in countries for which no typical farms are available in the IFCN database. Across the 117 typical farms in the 38 countries analysed, the average emission rate is 1.50 kg CO2 equivalents (CO2-eq.)/kg milk. The contribution of milk production to the global anthropogenic emissions is estimated at 1.3 Gt CO2-eq./year, accounting for 2.65% of total global anthropogenic emissions (49 Gt; IPCC, Synthesis Report for Policy Maker, Valencia, Spain, 2007). Discussion and conclusion We emphasise that our estimates of the contribution of milk production to global GHG emissions are subject to uncertainty. Part of the uncertainty stems from the choice of the appropriate methods for estimating emissions at the level of the individual animal.
11th European IFSA Symposium, Farming Systems Facing Global Challenges: Capacities and Strategies, Proceedings, Berlin, Germany, 1-4 April 2014, 2014
Life cycle assessment (LCA) is the accepted approach to simulate and compare carbon footprint (CF) of milk. The objective of this study was to apply LCA to compare CF of high performance confinement and grass-based dairy farms. Physical performance data from research herds were used to quantify CF of a high performance Irish grass-based dairy system and a top performing UK confinement dairy system. For the USA 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 systems. The model estimated all on and off-farm GHG sources associated with dairy production until milk is sold from the farm in kg of carbon dioxide equivalents (CO 2-eq) and allocated emissions between milk and meat. The CF of milk was calculated by expressing GHG emissions attributed to milk per t of energy corrected milk (ECM). The comparison showed the CF 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 USA confinement system (898 kg of CO 2-eq/t of ECM) when no GHG emissions were allocated to meat. However, without grassland carbon sequestration, the grass-based and confinement dairy systems had similar CF per t of ECM. Additionally, using different emission algorithms or methods to allocate GHG emissions between milk and meat affected the relative difference and order of dairy system CF. This indicates that further harmonization of several aspects of the LCA methodology is required to compare CF of divergent dairy systems. Relative to recent reports that assess the CF of milk from average Irish, UK and USA dairy systems, this case study indicates that top performing herds of the respective nations have CF about 30% lower than average systems. Although, differences between studies are partly explained by methodological inconsistency, the comparison suggests that there is potential to reduce the CF of milk in each of the nations by implementing practices that improve productivity.
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.
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.
International Dairy Journal, 2013
This article presents a cradle-to-grave analysis of the United States fluid milk supply chain greenhouse gas (GHG) emissions that are accounted from fertilizer production through consumption and disposal of milk packaging. Crop production and on-farm GHG emissions were evaluated using public data and 536 farm operation surveys. Milk processing data were collected from 50 dairy plants nationwide. Retail and consumer GHG emissions were estimated from primary data, design estimates, and publicly available data. Total GHG emissions, based primarily on 2007 to 2008 data, were 2.05 (90% confidence limits: 1.77e2.4) kg CO 2 e per kg milk consumed, which accounted for loss of 12% at retail and an additional 20% loss at consumption. A complementary analysis showed the entire dairy sector contributes approximately 1.9% of US GHG emissions. While the largest GHG contributors are feed production, enteric methane, and manure management; there are opportunities to reduce impacts throughout the supply chain.