Comparing the environmental efficiency of milk and beef production through life cycle assessment of interconnected cattle systems
Comparing the environmental efficiency of milk and beef production through life cycle assessment of interconnected cattle systems
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DOI：
10.1016/j.jclepro.2020.124108
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发表时间：
2020-12-20
影响因子：
11.1
通讯作者：
Chadwick, Dave
中科院分区：
文献类型：
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作者：
Mazzetto, Andre M.;Bishop, George;Chadwick, Dave
乳制品生产对环境有重大影响。目前，大多数分析牛奶生产环境负担的研究都采用归因生命周期评估（LCA）来对乳制品系统进行从摇篮到农场的分析。这种方法计算每公斤脂肪和蛋白质校正牛奶（FPCM）的环境足迹。然而，牛奶和牛肉生产本质上是相互关联的，对牛奶生产的狭隘关注忽视了奶牛场边界之外的牛系统之间更广泛的协同效应和权衡。我们首次应用了拉丁美洲奶牛和牛肉耦合生产的扩展边界LCA，将1千克FPCM加上100克牛肉作为功能单位（FU），以反映当前全球牛肉：牛奶需求比，并考虑到哥斯达黎加牛生产系统的复杂性。边界包括多余的奶牛犊牛的增肥，以及产生或避免提供FU所需的乳牛生产。使用农场LCA模型分析了552个哥斯达黎加农场（203个牛肉农场和349个奶牛场）的数据库，得出了五个影响类别（全球变暖潜势- GWP；富营养化；酸化；非生物资源枯竭；和土地占用- LO）的结果。归一化得分表明，养牛系统对人均GWP和LO负担的贡献最大。从摇篮到农场大门归因LCA显示，双用途农场生产的牛奶每公斤FPCM的GWP和LO足迹最大，而专业农场的足迹最小。扩大边界的LCA表明，与专业奶牛场相比，双重用途农场每公斤FPCM加100克牛肉产生的全球变暖潜能值更小，尽管仍然需要更多的土地。关键因素是畜群结构，影响牛肉产量和每头动物的产奶量，反映了乳制品专业化水平。这一关于养牛生产系统环境效率的新证据强调，在设计可持续集约化缓解战略时，必须考虑牛奶和牛肉生产以及相互关联的牛奶和牛肉生产系统中的多重环境压力。(C) 2020 Elsevier Ltd.版权所有。
Dairy production has a substantial environmental impact. Currently, most studies analysing the environmental burdens of milk production employ attributional Life Cycle Assessment (LCA), for cradle to farm-gate analysis of dairy systems. This approach calculates environmental footprints per kg fat and protein corrected milk (FPCM). However, milk and beef production are inherently interconnected, and a narrow focus on milk production neglects wider synergies and trade-offs across cattle systems, outside dairy farm boundaries. For the first time, we applied an expanded boundary LCA of coupled dairy and beef production in Latin America, considering 1 kg FPCM plus 100 g of beef as functional unit (FU) to reflect the current global beef:milk demand ratio and taking into account the complexities of Costa Rican cattle production systems. Boundaries encompassed fattening of surplus dairy calves and incurred or avoided suckler-beef production needed to deliver the FU. A database of 552 Costa Rican farms (203 beef and 349 dairy farms) was analysed using a farm LCA model to generate results across five impact categories (Global Warming Potential - GWP; Eutrophication; Acidification; Abiotic Resource Depletion; and Land Occupation - LO). Normalised scores indicated that cattle systems contribute most strongly to per capita GWP and LO burdens. Cradle to farm-gate attributional LCA showed that milk produced by dual-purpose farms had the largest GWP and LO footprints, whilst specialist farms had the smallest footprints, per kg FPCM. The expanded boundary LCA showed that dual-purpose farms generated smaller GWP footprints per kg FPCM plus 100 g beef than specialised dairy farms, though still required more land. Key factors were the herd structure, influencing the amount of beef produced, and milk yields per animal, reflecting the level of dairy specialisation. This new evidence on the environmental efficiency of cattle production systems emphasises the imperative to consider both milk and beef production as well as multiple environmental pressures across interconnected milk and beef production systems when designing sustainable intensification mitigation strategies. (C) 2020 Elsevier Ltd. All rights reserved.