Pathogen survival during livestock manure storage and following land application

This paper reports the first year results of field experiments to determine the survival times of pathogens in livestock manures during storage and following land application, using viable count methods. E. coli O157, Salmonella and Campylobacter survived in stored slurries and dirty water for up to three months, with Listeria surviving for up to three months. In contrast, all these pathogens survived for less than one month in solid manure heaps where temperatures greater than 55 degrees C were obtained. Following manure spreading to land, E. coli O157, Salmonella and Campylobacter generally survived in the soil for up to one month after application to both the sandy arable and clay loam grassland soils, whereas Listeria commonly survived for more than one month. These data are being used to develop guidelines on the management of manures to minimize the risks of pathogen transfer from animal manures to the human food chain.     

山西省畜禽业发展及粪尿养分时空变异

随着国家经济的高速发展和人民饮食结构的改变,畜禽养殖业由传统粗放式向规模化、集约化快速转变,畜禽粪尿的循环利用及其对环境的风险评价值得关注.本文利用统计资料和文献数据,通过使用食物链养分流动模型(NUFER)与GIS相结合,深入分析了山西省畜禽养殖量的变化特征,模拟了畜禽粪尿的产生量及其氮、磷养分的资源量,并从时空维度评价了山西省畜禽粪尿资源量及其环境风险.结果表明： 1978-2012年,山西省畜禽粪尿的产生量由1.61×10⁷ t增加至2.75×10⁷ t,增幅达1.71倍,粪尿氮由7.74×10⁴ t增长至17.32×10⁴ t,粪尿磷则由1.09×10⁴ t增长至3.39×10⁴ t,增幅分别达到2.38和3.10倍.除养殖总量增加之外,养殖结构和养殖方式也发生了重大变化.从空间分布看,2012年山西省耕地畜禽粪尿氮、磷承载量呈现晋北、晋中和晋东南高,中北部和西南部低的分布特征,耕地畜禽粪尿养分资源承载量在空间上分布极不平衡,这是区域养殖专业化程度与农业政策共同作用的结果.因此,应通过优化生产布局和区域间养分协同管理等手段,来调控畜禽粪尿的排放与循环利用,减少污染及环境风险,以实现畜禽粪尿养分资源的高效与可持续利用.     

Using land-use management policies to reduce the environmental impacts of livestock farming

The manure produced by livestock animals across all of Japan is approximately 90 million tonnes a year, which represents approximately 25% of the overall biomass of Japan's natural resources. In recent decades, the supply of the livestock animal compost has decreased due to various factors—a decrease in fodder, decrease in deserted cultivated land and increase in the importation of fodder—while the domestic animal manure portion of the livestock waste and associated increases have risen dramatically. Most of this manure leads to negative environmental effects by increasing nitrogen (N) loads in rainfall events and causing excess fertilisation, especially in agricultural areas. Animal manure accounts for approximately 23% of all categories of waste in Japan and 89% of all livestock waste in Japan. This 89% of livestock waste is generally utilised as compost or fertiliser. In Japan, the oversupply of fertiliser has already been identified as a problem in the field of agriculture. To address these issues, we assessed the two-dimensional (2D) concentration distribution of N in a water system to specifically analyse the effect of livestock contamination. From the results of this analysis, we observed that industrial factory wastewater creates a narrow localised impact, while the livestock industry creates a medium/broad impact. Therefore, this study provided a simultaneous representation of the total and specific impacts of both human and livestock activities under typical rural catchment conditions. The difference between the environmental impact index value of the current situation and the policy effect was quantitatively assessed. These results will contribute to the construction of a practical decision-making method. Additionally, reduced greenhouse gas emissions, a widely expanded network of protected areas and/or efforts to provide corridors to ease species movement may be necessary to achieve more globally sustainable practices.     

The future of anaerobic digestion and biogas utilization

One of the common tendencies of animal production activities in Europe and in developed countries in general is to intensify the animal production and to increase the size of the animal production units. High livestock density is always accompanied by production of a surplus of animal manure, representing a considerable pollution threat for the environment in these areas. Avoiding over-fertilization is not only important for environmental protection reasons but also for economical reasons. Intensive animal production areas need therefore suitable manure management, aiming to export and to redistribute the excess of nutrients from manure and to optimize their recycling.     

畜禽粪便好氧堆肥过程氧化亚氮排放机制

好氧堆肥是实现畜禽粪便处理及资源化的有效途径,但畜禽粪便好氧堆肥过程是全球温室气体N2O的潜在来源,与全球温室效应和大气臭氧空洞等问题密切相关.随着畜禽养殖规模的扩大和畜禽粪便堆肥产量的急剧提升,畜禽粪便好氧堆肥过程N2O排放问题日趋严重,堆肥过程N2O排放机制机理研究引发学者们的关注.本文综述了畜禽粪便好氧堆肥过程中N2O的产生途径、排放规律、排放影响因素及其相关微生物学机理研究动态,总结了该过程中减排N2O的措施,并对该领域的研究趋势进行了展望.     

利用畜禽粪便饲养家蝇的技术及应用

随着畜牧业的发展,粪便的污染和蛋白饲料的缺乏已成为养殖业中急待解决的两个突出问题。近些年来,利用蝇蛆转化畜禽粪便,蝇蛆作为饲料来养殖禽畜的技术渐趋成熟。文章归纳并综述了利用禽畜粪便养殖蝇蛆的理论和技术,对蝇蛆饲料和蛆粪有机肥的应用和效果做了简要的阐述。     

Biochar from animal manure: A critical assessment on technical feasibility,economic viability,and ecological impact

Animal manure has been used to manage soil fertility since the dawn of agriculture. It provides plant nutrients and improves soil fertility. In the last decades, animal husbandry has been significantly expanded globally. Its economics were optimized via the (international) trade of feed, resulting in a surplus of animal manure in areas with intensive livestock farming. Potentially toxic elements (PTEs), pathogenic microorganisms, antibiotic residues, biocides, and other micropollutants in manure threaten animal, human, and environmental health. Hence, manure application in crop fields is increasingly restricted, especially in hotspot regions with intensive livestock activities. Furthermore, ammonia volatilization and greenhouse gas (GHG) emissions during manure storage, field application, and decomposition contribute to air pollution and climate change. Conventional manure management scenarios such as composting and anaerobic digestion partially improve the system but cannot guarantee to eliminate sanitary and contamination risks and only marginally reducing its climate burden. Hence, this review discusses the potential of pyrolysis, the thermochemical conversion under oxygen-limited conditions as an alternative treatment for animal manure providing energy and biochar. Manure pyrolysis reduces the bioavailability of PTEs, eliminates pathogenic microorganisms and organic micropollutants, and reduces GHG emissions. Pyrolysis also results in the loss of nitrogen, which can be minimized by pretreatment, that is, after removing soluble nitrogen fraction of manure, for example, by digestion and stripping of ammonia–nitrogen or liquid–solid separation. However, conclusions on the effect of manure pyrolysis on crop yield and fertilization efficiencies are hampered by a lack of nutrient mass balances based on livestock unit equivalent comparisons of manure and manure biochar applications. Hence, it is essential to design and conduct experiments in more practically relevant scenarios and depict the observations based on the amount of manure used to produce a certain amount of biochar.     

Prevention and control of losses of gaseous nitrogen compounds in livestock operations: a review

Nitrogen (N) losses from livestock houses and manure storage facilities contribute greatly to the total loss of N from livestock farms. Volatilisation of ammonia (NH3) is the major process responsible for the loss of N in husbandry systems with slurry (where average dry matter content varies between 3 and 13%). Concerning this volatilisation of NH3, the process parameters of pH and air temperature are crucial. During a period of approximately 10 years, systematic measurements of NH3 losses originating from a large variety of different livestock houses were made. One of the problems with NH3 emissions is the large variation in the measured data due to the season, the production of the animals, the manure treatment, type of livestock house, and the manure storage. Generally speaking, prevention and control of NH3 emission can be done by control of N content in the manure, moisture content, pH, and temperature. In houses for growing pigs, a combination of simple housing measures can be taken to greatly reduce NH3 emissions. In houses for laying hens, the control of the manure drying process determines the emission of NH3. Monteny has built an NH3 production model with separate modules for the emission of the manure storage under the dairy house and the floor in the house. Manure spreading is also a major source of NH3 emission and is dependent on slurry composition, environmental conditions, and farm management. The effects of these factors have been employed in a model. Losses via NO, N2O, and N2 are important in husbandry systems with solid manure and straw. The number of experimental data is, however, very limited. As N2O is an intermediate product of complex biochemical processes of nitrification and denitrification, optimal conditions are the key issues in N2O reduction strategies. We may expect that in the near future the emission of greenhouse gases will get the same attention from policy makers as NH3. Sustainable livestock production has to combine low emissions of gaseous N compounds with acceptable odour emissions, low emissions of greenhouse gases, and acceptable standards of animal welfare. For the entrepreneur, the strategy must be built on the regulations, the special conditions of his farm, and what is reasonably achievable.     

Livestock waste treatment systems for reducing environmental exposure to hazardous enteric pathogens: Some considerations

Intensive livestock production systems produce significant quantities of excreted material that must be managed to protect water, air, and crop quality. Many jurisdictions mandate how livestock wastes are managed to protect adjacent water quality from microbial and chemical contaminants that pose an environmental and human health challenge. Here, we consider innovative livestock waste treatment systems in the context of multi-barrier strategies for protecting water quality from agricultural contamination. Specifically, we consider some aspects of how enteric bacterial populations can evolve during manure storage, how their fate following land application of manure can vary according to manure composition, and finally the challenge of distinguishing enteric pathogens of agricultural provenance from those of other sources of fecal pollution at a policy-relevant watershed scale. The beneficial impacts of livestock waste treatment on risk to humans via exposure to manured land are illustrated using quantitative microbial risk assessment (QMRA) scenarios. Overall, innovative livestock treatment systems offer a crucially important strategy for making livestock wastes more benign before they are released into the broader environment.     

Animal Board Invited Review: Comparing conventional and organic livestock production systems on different aspects of sustainability

To sustainably contribute to food security of a growing and richer world population, livestock production systems are challenged to increase production levels while reducing environmental impact, being economically viable, and socially responsible. Knowledge about the sustainability performance of current livestock production systems may help to formulate strategies for future systems. Our study provides a systematic overview of differences between conventional and organic livestock production systems on a broad range of sustainability aspects and animal species available in peer-reviewed literature. Systems were compared on economy, productivity, environmental impact, animal welfare and public health. The review was limited to dairy cattle, beef cattle, pigs, broilers and laying hens, and to Europe, North America and New Zealand. Results per indicators are presented as in the articles without performing additional calculations. Out of 4171 initial search hits, 179 articles were analysed. Studies varied widely in indicators, research design, sample size and location and context. Quite some studies used small samples. No study analysed all aspects of sustainability simultaneously. Conventional systems had lower labour requirements per unit product, lower income risk per animal, higher production per animal per time unit, higher reproduction numbers, lower feed conversion ratio, lower land use, generally lower acidification and eutrophication potential per unit product, equal or better udder health for cows and equal or lower microbiological contamination. Organic systems had higher income per animal or full time employee, lower impact on biodiversity, lower eutrophication and acidification potential per unit land, equal or lower likelihood of antibiotic resistance in bacteria and higher beneficial fatty acid levels in cow milk. For most sustainability aspects, sometimes conventional and sometimes organic systems performed better, except for productivity, which was consistently higher in conventional systems. For many aspects and animal species, more data are needed to conclude on a difference between organic and conventional livestock production systems.     

Sustainable intensive livestock production demands manure and exhaust air treatment technologies

Intensive livestock production is connected with a number of environmental effects, including discharges to soils and surface waters and emissions to the atmosphere. In areas with a high livestock density the low availability of nearby arable land, together with the preferred use of chemical fertilizer by arable farmers, results in high off-farm disposal costs for manure. Furthermore, ammonia abatement technologies, such as treatment of exhaust air, are important as ammonia emissions may account up to a quarter of the total nitrogen flux.     

Mitigating climate change: the role of domestic livestock

Livestock contribute directly (i.e. as methane and nitrous oxide (N2O)) to about 9% of global anthropogenic greenhouse gas (GHG) emissions and around 3% of UK emissions. If all parts of the livestock production lifecycle are included (fossil fuels used to produce mineral fertilizers used in feed production and N2O emissions from fertilizer use; methane release from the breakdown of fertilizers and from animal manure; land-use changes for feed production and for grazing; land degradation; fossil fuel use during feed and animal production; fossil fuel use in production and transport of processed and refrigerated animal products), livestock are estimated to account for 18% of global anthropogenic emissions, but less than 8% in the UK. In terms of GHG emissions per unit of livestock product, monogastric livestock are more efficient than ruminants; thus in the UK, while sheep and cattle accounted for 32% of meat production in 2006, they accounted for 48% of GHG emissions associated with meat production. More efficient management of grazing lands and of manure can have a direct impact in decreasing emissions. Improving efficiency of livestock production through better breeding, health interventions or improving fertility can also decrease GHG emissions through decreasing the number of livestock required per unit product. Increasing the energy density of the diet has a dual effect, decreasing both direct emissions and the numbers of livestock per unit product, but, as the demands for food increase in response to increasing human population and a better diet in some developing countries, there is increasing competition for land for food v. energy-dense feed crops. Recalculating efficiencies of energy and protein production on the basis of human-edible food produced per unit of human-edible feed consumed gave higher efficiencies for ruminants than for monogastric animals. The policy community thus have difficult decisions to make in balancing the negative contribution of livestock to the environment against the positive benefit in terms of food security. The animal science community have a responsibility to provide an evidence base which is objective and holistic with respect to these two competing challenges.     

抗生素耐药基因在畜禽粪便-土壤系统中的分布、扩散及检测方法

抗生素耐药基因作为一种新型的环境污染物已引起研究者的高度关注。畜禽养殖业长期将抗生素添加到饲料中,在促进动物生长、预防和治疗动物疾病等方面起了重要作用。这些抗生素大多数不能被动物完全吸收,在动物肠道中诱导出耐抗生素细菌和抗生素耐药基因,并随着粪便排出体外。畜禽粪便作为重要的抗生素、耐抗生素细菌和抗生素耐药基因储存库,通过堆粪、施肥等农业活动进入土壤环境中,可刺激土壤中耐抗生素细菌和抗生素耐药基因的富集。耐药基因借助于基因水平转移等方式在土壤介质中进一步传播扩散,甚至进入植物中随食物链传播,对生态环境和人类健康造成极大的威胁。为了正确评估抗生素耐药基因的生态风险,本文结合国内外相关研究,系统阐述了畜禽粪便-土壤系统中抗生素耐药基因的来源、分布及扩散机制,同时探讨了细菌耐药性的主要研究方法,指出堆肥化处理仍是目前去除抗生素耐药基因的主要手段,并对今后的研究方向进行展望。     

Management considerations for organic waste use in agriculture

Organic wastes are utilized in agriculture mainly for improving the soil physical and chemical properties and for nutrient sources for growing crops. The major source of organic waste used in agriculture is animal manure, but small amounts of food processing and other industrial wastes (along with municipal wastes) are also applied to land. In the last 35 years, and especially in the last 10 years, there have been increasing environmental regulations affecting farms that have resulted in more animal manure treatment options, and thus affecting characteristics of residues that are subsequently applied to land. Farms are being assessed for nutrient balances, with the entire nutrient and manure management system evaluated for best management alternatives. Because of inadequate available land on the animal farm in some cases, organic wastes must be treated and/or transported to other farms, or utilized for horticultural or other uses. This paper discusses the various factors and challenges for utilizing organic wastes in agriculture.     

Veterinary antibiotics in the aquatic and terrestrial environment

The fate of antibiotics in the environment, and especially antibiotics used in animal husbandry, is subject to recent studies and the issue of this review. The assumed quantity of antibiotics excreted by animal husbandry adds up to thousands of tonnes per year. Administered medicines, their metabolites or degradation products reach the terrestrial and aquatic environment by the application of manure or slurry to areas used agriculturally, or by pasture-reared animals excreting directly on the land, followed by surface run-off, driftage or leaching in deeper layers of the earth. The scientific interest in antimicrobially active compounds in manure and soil, but also in surface and ground water, has increased during the last decade. On the one side, scientific interest has focused on the behaviour of antibiotics and their fate in the environment, on the other hand, their impact on environmental and other bacteria has become an issue of research. Analytical methods have now been developed appropriately and studies using these new techniques provide accurate data on concentrations of antimicrobial compounds and their residues in different organic matters. Some antibiotics seem to persist a long time in the environment, especially in soil, while others degrade very fast. Not only the fate of these pharmaceuticals but their origin as well is an object of scientific interest. Besides human input via wastewater and other effluents, livestock production has been recognised as a source of contamination. One main concern with regard to the excessive use of antibiotics in livestock production is the potential promotion of resistance and the resulting disadvantages in the therapeutic use of antimicrobials. Since the beginning of antibiotic therapy, more and more resistant bacterial strains have been isolated from environmental sources showing one or multiple resistance. There have been several attempts to use antibiotic resistance patterns in different bacteria as indicators for various sources of faecal pollution. This review gives an overview of the available data on the present use of veterinary antibiotics in agriculture, on the occurrence of antibiotic compounds and resistant bacteria in soil and water and demonstrates the need for further studies.     

Eco-efficient approaches to land management: a case for increased integration of crop and animal production systems

Eco-efficiency is concerned with the efficient and sustainable use of resources in farm production and land management. It can be increased either by altering the management of individual crop and livestock enterprises or by altering the land-use system. This paper concentrates on the effects of crop sequence and rotation on soil fertility and nutrient use efficiency. The potential importance of mixed farming involving both crops and livestock is stressed, particularly when the systems incorporate biological nitrogen fixation and manure recycling. There is, however, little evidence that the trend in developed countries to farm-level specialization is being reduced. In some circumstances legislation to restrict diffuse pollution may provide incentives for more diverse eco-efficient farming and in other circumstances price premia for produce from eco-efficient systems, such as organic farming, and subsidies for the provision of environmental services may provide economic incentives for the adoption of such systems. However, change is likely to be most rapid where the present systems lead to obvious reductions in the productive potential of the land, such as in areas experiencing salinization. In other situations, there is promise that eco-efficiency could be increased on an area-wide basis by the establishment of linkages between farms of contrasting type, particularly between specialist crop and livestock farms, with contracts for the transfer of manures and, to a lesser extent, feeds.     

Livestock production: recent trends, future prospects

The livestock sector globally is highly dynamic. In developing countries, it is evolving in response to rapidly increasing demand for livestock products. In developed countries, demand for livestock products is stagnating, while many production systems are increasing their efficiency and environmental sustainability. Historical changes in the demand for livestock products have been largely driven by human population growth, income growth and urbanization and the production response in different livestock systems has been associated with science and technology as well as increases in animal numbers. In the future, production will increasingly be affected by competition for natural resources, particularly land and water, competition between food and feed and by the need to operate in a carbon-constrained economy. Developments in breeding, nutrition and animal health will continue to contribute to increasing potential production and further efficiency and genetic gains. Livestock production is likely to be increasingly affected by carbon constraints and environmental and animal welfare legislation. Demand for livestock products in the future could be heavily moderated by socio-economic factors such as human health concerns and changing socio-cultural values. There is considerable uncertainty as to how these factors will play out in different regions of the world in the coming decades.     

The effect of climate change on the occurrence and prevalence of livestock diseases in Great Britain: a review

There is strong evidence to suggest that climate change has, and will continue to affect the occurrence, distribution and prevalence of livestock diseases in Great Britain (GB). This paper reviews how climate change could affect livestock diseases in GB. Factors influenced by climate change and that could affect livestock diseases include the molecular biology of the pathogen itself; vectors (if any); farming practice and land use; zoological and environmental factors; and the establishment of new microenvironments and microclimates. The interaction of these factors is an important consideration in forecasting how livestock diseases may be affected. Risk assessments should focus on looking for combinations of factors that may be directly affected by climate change, or that may be indirectly affected through changes in human activity, such as land use (e.g. deforestation), transport and movement of animals, intensity of livestock farming and habitat change. A risk assessment framework is proposed, based on modules that accommodate these factors. This framework could be used to screen for the emergence of unexpected disease events.     

Nitrogen in global animal production and management options for improving nitrogen use efficiency

Animal production systems convert plant protein into animal protein. Depending on animal species, ration and management, between 5% and 45 % of the nitrogen (N) in plant protein is converted to and deposited in animal protein. The other 55%-95% is excreted via urine and feces, and can be used as nutrient source for plant (= often animal feed) production. The estimated global amount of N voided by animals ranges between 80 and 130 Tg N per year, and is as large as or larger than the global annual N fertilizer consumption. Cattle (60%), sheep (12%) and pigs (6%) have the largest share in animal manure N production.The conversion of plant N into animal N is on average more efficient in poultry and pork production than in dairy production, which is higher than in beef and sheep production. However, differences within a type of animal production system can be as large as differences between types of animal production systems, due to large effects of the genetic potential of animals, animal feed and management. The management of animals and animal feed, together with the genetic potential of the animals, are key factors to a high efficiency of conversion of plant protein into animal protein.The efficiency of the conversion of N from animal manure, following application to land, into plant protein ranges between 0 and 60%, while the estimated global mean is about 15%. The other 40%- 100% is lost to the wider environment via NH3 volatilization, denitrification, leaching and run-off in pastures or during storage and/or following application of the animal manure to land. On a global scale, only 40%-50% of the amount of N voided is collected in barns, stables and paddocks, and only half of this amount is recycled to crop land. The N losses from animal manure collected in barns, stables and paddocks depend on the animal manure management system. Relative large losses occur in confined animal feeding operations, as these often lack the land base to utilize the N from animal manure effectively.Losses will be relatively low when all manure are collected rapidly in water-tight and covered basins, and when they are subsequently applied to the land in proper amounts and at the proper time, and using the proper method (low-emission techniques).There is opportunity for improving the N conversion in animal production systems by improving the genetic production potential of the herd, the composition of the animal feed, and the management of the animal manure. Coupling of crop and animal production systems, at least at a regional scale, is one way to high N use efficiency in the whole system. Clustering of confined animal production systems with other intensive agricultural production systems on the basis of concepts from industrial ecology with manure processing is another possible way to improve Nuse efficiency.     

Nitrogen in global animal production and management options for improving nitrogen use efficiency

Animal production systems convert plant protein into animal protein. Depending on animal species, ration and management, between 5% and 45 % of the nitrogen (N) in plant protein is converted to and deposited in animal protein. The other 55%-95% is excreted via urine and feces, and can be used as nutrient source for plant (= often animal feed) production. The estimated global amount of N voided by animals ranges between 80 and 130 Tg N per year, and is as large as or larger than the global annual N fertilizer consumption. Cattle (60%), sheep (12%) and pigs (6%) have the largest share in animal manure N production. The conversion of plant N into animal N is on average more efficient in poultry and pork production than in dairy production, which is higher than in beef and sheep production. However, differences within a type of animal production system can be as large as differences between types of animal production systems, due to large effects of the genetic potential of animals, animal feed and management. The management of animals and animal feed, together with the genetic potential of the animals, are key factors to a high efficiency of conversion of plant protein into animal protein. The efficiency of the conversion of N from animal manure, following application to land, into plant protein ranges between 0 and 60%, while the estimated global mean is about 15%. The other 40%-100% is lost to the wider environment via NH3 volatilization, denitrification, leaching and run-off in pastures or during storage and/or following application of the animal manure to land. On a global scale, only 40%-50% of the amount of N voided is collected in barns, stables and paddocks, and only half of this amount is recycled to crop land. The N losses from animal manure collected in barns, stables and paddocks depend on the animal manure management system. Relative large losses occur in confined animal feeding operations, as these often lack the land base to utilize the N from animal manure effectively. Losses will be relatively low when all manure are collected rapidly in water-tight and covered basins, and when they are subsequently applied to the land in proper amounts and at the proper time, and using the proper method (low-emission techniques). There is opportunity for improving the N conversion in animal production systems by improving the genetic production potential of the herd, the composition of the animal feed, and the management of the animal manure. Coupling of crop and animal production systems, at least at a regional scale, is one way to high N use efficiency in the whole system. Clustering of confined animal production systems with other intensive agricultural production systems on the basis of concepts from industrial ecology with manure processing is another possible way to improve N use efficiency.