School of Agriculture, Food, and Rural Development, Newcastle University, Newcastle upon Tyne, NE1 7RU United Kingdom.
Poult Sci. 2012 Jan;91(1):26-40. doi: 10.3382/ps.2011-01635.
The aim of this study was to apply a life cycle assessment (LCA) method, from cradle to gate, to quantify the environmental burdens per 1,000 kg of eggs produced in the 4 major hen-egg production systems in the United Kingdom: 1) cage, 2) barn, 3) free range, and 4) organic. The analysis was based on an approach that applied a structural model for the industry and mechanistic submodels for animal performance, crop production, and nutrient flows. Baseline feeds representative of those used by the UK egg production industry were used. Typical figures from the UK egg production industry, feed intake, mortality of birds, farm energy, and material use in different systems were applied. Monte Carlo simulations were used to quantify the uncertainties in the outputs and allow for comparisons between the systems. The number of birds required to produce 1,000 kg of eggs was highest in the organic and lowest in the cage system; similarly, the amount of feed consumed per bird was highest in the organic and lowest in the cage system. These general differences in productivity largely affected the differences in the environmental impacts between the systems. Feed production, processing, and transport caused greater impacts compared with those from any other component of production; that is, 54 to 75% of the primary energy use and 64 to 72% of the global warming potential of the systems. Electricity (used mainly for ventilation, automatic feeding, and lighting) had the second greatest impact in primary energy use (16-38%). Gas and oil (used mainly for heating in pullet rearing and incineration of dead layer birds) used 7 to 14% of the total primary energy. Manure had the greatest impact on the acidification and eutrophication potentials of the systems because of ammonia emissions that contributed to both of these potentials and nitrate leaching that only affected eutrophication potential. The LCA method allows for comparisons between systems and for the identification of hotspots of environmental impacts that could be subject to mitigation.
本研究旨在采用从摇篮到大门（cradle to gate）的生命周期评估（LCA）方法，量化英国四大蛋鸡生产系统（1）笼养、2）舍饲、3）散养和 4）有机）每生产 1000 公斤鸡蛋的环境负担。分析基于一种应用行业结构模型和动物性能、作物生产和养分流动的机制子模型的方法。使用了代表英国蛋鸡生产行业使用的基础饲料。应用了英国蛋鸡生产行业的典型数据，包括饲料摄入量、鸟类死亡率、农场能源和不同系统中的材料使用。蒙特卡罗模拟用于量化输出的不确定性，并允许对系统进行比较。生产 1000 公斤鸡蛋所需的鸟类数量在有机系统中最高，在笼养系统中最低；同样，有机系统中每只鸟消耗的饲料量最高，笼养系统中最低。这些生产力方面的总体差异在很大程度上影响了系统之间环境影响的差异。饲料生产、加工和运输造成的影响比生产的任何其他组成部分都大；也就是说，系统的主要能源使用的 54%到 75%和全球变暖潜能值的 64%到 72%来自这些方面。电力（主要用于通风、自动喂养和照明）在主要能源使用方面的影响排名第二（16%到 38%）。天然气和石油（主要用于育雏期的加热和淘汰鸡的焚烧）使用了总初级能源的 7%到 14%。由于氨排放对这两种潜力都有贡献，以及硝酸盐淋溶仅对富营养化潜力有影响，因此粪便对系统的酸化和富营养化潜力影响最大。LCA 方法允许对系统进行比较，并确定可以进行缓解的环境影响热点。
