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Abstract：
We reviewed specific literature for emissions of ammonia (NH3) and odours from all stages of pig production together with nitrogen (N) leaching from raising pigs outdoors. Emissions of NH3 decrease with decreases in the crude protein (CP) content of pig diets, at all stages of manure management. The CPs of pig diets have been greatly reduced by matching the CP content to the protein required at each stage of the animals\' growth and by using synthetic essential amino acids to minimise total CP intake. The CP contents of the dietary ingredients needed to provide energy for the animals impose further limits to reductions in dietary CP. Housing systems have been designed and evaluated which offer potential for reducing NH3 emissions. However such designs may not be applicable at all stages of the pigs\' development and the careful management needed to ensure their effective working may be costly and difficult to implement on commercial farms. The factors behind odour emissions are less well characterised. Reducing diet CP to 160 g CP kg(-1) has been shown to reduce odour emissions but further CP reductions may increase them. Some reductions in odour emissions from buildings can be achieved by careful management of the ventilation rate but the most effective measures to reduce emissions of NH3 and odours are to cover slurry stores and to inject slurry into soil. Changes in the feeding and management of outdoor pigs mean that N leaching losses may be up to 50% less than previously reported. No studies have been undertaken that compare the N leached from pigs raised outdoors, versus that arising from the application of pig manure from an equal number of housed pigs. As a precursor to any field study, current models could be used to provide a first estimate of any systematic differences.
摘要：
我们回顾了有关养猪生产各个阶段的氨（NH3）和气味排放以及户外养猪的氮（N）浸出的具体文献。NH3的排放量随着猪日粮粗蛋白（CP）含量的减少而减少，在粪肥管理的各个阶段。通过将CP含量与动物生长的每个阶段所需的蛋白质相匹配，并使用合成必需氨基酸来最大程度地减少总CP摄入量，从而大大降低了猪日粮的CP。为动物提供能量所需的膳食成分的CP含量进一步限制了膳食CP的减少。已经设计和评估了为减少NH3排放提供潜力的外壳系统。然而,此类设计可能不适用于猪只发展的所有阶段,确保其有效工作所需的谨慎管理可能成本高昂且难以在商业农场实施。气味排放背后的因素没有得到很好的表征。已证明将饮食CP减少到160gCPkg（-1）可以减少气味排放，但进一步减少CP可能会增加气味排放。通过仔细管理通风率可以减少建筑物的气味排放，但减少NH3和气味排放的最有效措施是覆盖泥浆储存并将泥浆注入土壤。户外猪的饲养和管理的变化意味着N浸出损失可能比以前报道的减少多达50％。没有进行过比较从户外饲养的猪中浸出的氮的研究，与从相同数量的饲养猪中施用猪粪所产生的差异相比。作为任何实地研究的先驱，目前的模型可以用来提供任何系统性差异的第一个估计。
