A step forward in quantifying the substitutability of secondary materials in waste management life cycle assessment studies.

Life Cycle Assessment (LCA) is a widespread tool used to guide decision-makers towards optimal strategic choices for sustainable growth. A key aspect of LCA studies of waste management systems where recycling activities are present is to account for resource recovery and the related substitution effects. Although multiple scientific papers assume a 1:1 substitution ratio between similar materials/products, this is often incorrect as the actual ratio is likely to vary. The focus of this paper is on the calculation of the substitutability coefficient for secondary materials based on technical characteristics. A state of the art literature review showed that many different calculation procedures were applied, which led to a wide variety of substitutability coefficients (sometimes provided under different terminology). In this perspective, the objective of this paper is to provide guidelines on the procedure to be followed to calculate the substitutability coefficient for secondary materials, based on technical characteristics. These guidelines are then applied to two waste management case studies, one dealing with bottom ashes from incineration and the other with plastic waste. In total, sixteen technical substitutability coefficients are given for ten secondary materials, based on state of the art and presented case studies. The paper thus represents a step forward in quantifying the substitutability of secondary materials in waste management LCA studies. The guidelines presented may allow other case studies to enrich the list of coefficients, useful for all LCA practitioners in a harmonized way allowing a more correct evaluation of the environmental impacts associated with recycling activities.

Quantitative assessment of biosecurity in broiler farms using Biocheck.UGent in Central Luzon, Philippines.

The biosecurity status of 397 broiler farms in Central Luzon, the highest poultry meat-producing region in the Philippines, was assessed using Biocheck.Ugent. This online biosecurity assessment tool quantifies biosecurity level or compliance of surveyed farms. The system generates scores that reflect the current biosecurity status of each farm in terms of the different external and internal biosecurity measures being implemented in each farm. It was initially developed for pigs and broilers but recently is available for layers, swine, and cattle (beef, dairy, and veal). The overall biosecurity score of broiler farms in Central Luzon was 71.2%, with average external and internal biosecurity scores of 68.5 and 77.2%, respectively. Bataan had the highest biosecurity scores (76.5%) compared with the other 6 provinces. This was also true for the external and internal biosecurity scores of the province, with mean scores of 72.1 and 80.1%, respectively. Of the 11 subcategories of external and internal biosecurity that were assessed, purchase of day-old chicks, feeds and water supply, supply of materials, cleaning and disinfection, and materials between compartments had scores higher than the global scores. Low scores were generated from transport of live animals and infrastructure and biological vectors. The mean biosecurity score of farms with traditional/conventional type of housing was 7.8% lower than that with tunnel vent housing. Every year as the farm gets older, there was a corresponding drop of 0.2% in the biosecurity score. Biosecurity measures are in place in broiler farms in the country. However, there were areas with low scores which need to be prioritized to improve and upgrade the farms' biosecurity status. To date, this is the first quantitative assessment of biosecurity in broiler farms in the Philippines. High biosecurity scores may entail greater protection from disease incursion.

Herd-specific interventions to reduce antimicrobial usage in pig production without jeopardising technical and economic performance.

Pig farmers are strongly encouraged to reduce their antimicrobial usage in order to reduce the risk of antimicrobial resistance. Herd-level intervention is needed to achieve national and European reduction targets. Alternative, especially preventive measures, have to be implemented to reduce the need for antimicrobial treatments. However, little is known about the feasibility, effectiveness and return on investment of such measures. The objective of this study was to assess, across four countries, the technical and economic impact of herd-specific interventions aiming at reducing antimicrobial usage in pig production while implementing alternative measures. An intervention study was conducted between February 2014 and August 2015 in 70 farrow-to-finish pig farms located in Belgium, France, Germany and Sweden. Herd-specific interventions were defined together with the farmer and the herd veterinarian. Farms were followed over one year and their antimicrobial usage and technical performance were compared with values from the year before intervention. Compliance with the intervention plan was also monitored. Changes in margin over feed cost and net farm profit were estimated in a subset of 33 Belgian and French farms with sufficient data, using deterministic and stochastic modeling. Following interventions, a substantial reduction in antimicrobial use was achieved without negative impact the overall farm technical performance. A median reduction of 47.0% of antimicrobial usage was achieved across four countries when expressed in terms of treatment incidence from birth to slaughter, corresponding to a 30.5% median reduction of antimicrobial expenditures. Farm compliance with intervention plans was high (median: 93%; min-max: 20; 100) and farms with higher compliance tended to achieve bigger reduction (ρ=-0.18, p=0.162). No association was found between achieved reduction and type or number of alternative measures implemented. Mortality in suckling piglets, weaners and fatteners, daily weight gain and feed conversion ratio did not significantly change over the course of the study, while the number of weaned piglets per sow per year slightly increased. The median change in net farm profit among Belgian and French farms was estimated to be €4.46 (Q25-Q75:-32.54; 80.50) and €1.23 (Q25-Q75:-32.55; 74.45) per sow per year using the detererministic and stochastic models, respectively. It was more influenced by a change in feed conversion ratio and daily weight gain than by a change in antimicrobial expenditures or intervention direct net cost. Therefore, costs of alternative measures should not be perceived as a barrier, but rather as an opportunity to optimise production practices for sustained productivity and improved animal health.

Reducing Antimicrobial Usage in Pig Production without Jeopardizing Production Parameters.

Antimicrobial usage (AMU) has been described to be high in pig production. Although farmers are aware of the high usage, little is known about intervention to improve the situation. This study evaluated the extent to which AMU could be reduced in pig production by the optimization of herd management, biosecurity status, vaccination strategy, anthelmintic therapy and advice on prudent AMU. Furthermore, the effects of these interventions on the herd production results were explored. This intervention study was conducted on 61 Flemish pig herds and included three visits per herd. During the initial visit, information was gathered on herd management, biosecurity status (quantified by means of the Biocheck.UGent™ risk-based scoring system), vaccination strategy, anthelmintic therapy and AMU. This info was then translated into a herd-specific action plan which was discussed with the farmer and herd veterinarian/other advisors during the second visit. In the final herd visit (±8 months later), comparable data were obtained to evaluate the progress. Overall, a significant improvement of 2.4 points external and 7 points internal biosecurity on the herds was obtained, combined with additional vaccination, anthelmintic therapy and prudent AMU. This was accompanied by a significant reduction in the AMU with a decrease of 52% for the pigs from birth till slaughter and 32% for breeding animals, based on treatment incidences (TIs) and included an important reduction in the use of critically important antimicrobials. More importantly, the increased biosecurity levels and decreased AMU were combined with significantly improved technical results such as the number of weaned piglets per sow per year (+1.1), daily weight gain (+5.9 g/day) and mortality in the finisher period (-0.6%). Guided interventions as a team effort of farmer and herd veterinarian/other advisors have shown to be a promising method in the reduction of AMU in pig production.

Guidance on the Selection of Appropriate Indicators for Quantification of Antimicrobial Usage in Humans and Animals.

An increasing variety of indicators of antimicrobial usage has become available in human and veterinary medicine, with no consensus on the most appropriate indicators to be used. The objective of this review is therefore to provide guidance on the selection of indicators, intended for those aiming to quantify antimicrobial usage based on sales, deliveries or reimbursement data. Depending on the study objective, different requirements apply to antimicrobial usage quantification in terms of resolution, comprehensiveness, stability over time, ability to assess exposure and comparability. If the aim is to monitor antimicrobial usage trends, it is crucial to use a robust quantification system that allows stability over time in terms of required data and provided output; to compare usage between different species or countries, comparability must be ensured between the different populations. If data are used for benchmarking, the system comprehensiveness is particularly crucial, while data collected to study the association between usage and resistance should express the exposure level and duration as a measurement of the exerted selection pressure. Antimicrobial usage is generally described as the number of technical units consumed normalized by the population at risk of being treated in a defined period. The technical units vary from number of packages to number of individuals treated daily by adding different levels of complexity such as daily dose or weight at treatment. These technical units are then related to a description of the population at risk, based either on biomass or number of individuals. Conventions and assumptions are needed for all of these calculation steps. However, there is a clear lack of standardization, resulting in poor transparency and comparability. By combining study requirements with available approaches to quantify antimicrobial usage, we provide suggestions on the most appropriate indicators and data sources to be used for a given study objective.

Opinions of veterinarians on antimicrobial use in farm animals in Flanders and the Netherlands.

Veterinarians play an important role in the reduction of antimicrobial use in farm animals. This study aims to quantify opinions of veterinarians from the Netherlands and Flanders regarding antimicrobial use and resistance issues in farm animals. An online survey was sent out to 678 and 1100 farm animal veterinarians in Flanders and the Netherlands, of which 174 and 437 were returned respectively. Suboptimal climate conditions were regarded as the most important cause for high antimicrobial use in farm animals. Flemish veterinarians also regarded insufficient biosecurity measures and farmers' mentality as important determinants, while the Dutch respondents ranked insufficient immunity of young animals and economic considerations of farmers as major causes. The majority of Dutch respondents (63.8 per cent) supported the existing national policy, which aimed to halve veterinary antimicrobial use, while the Flemish (32.9 per cent) were less supportive of such a policy. Improvements in housing and climate conditions, biosecurity measures and strict control of specific infectious diseases were seen as important and promising measures to reduce antimicrobial use. To reduce antimicrobial use in farm animals, some shared approaches might be applicable in both countries. However, cultural, political and societal differences between Flanders and the Netherlands require differentiated approaches to reduce veterinary antimicrobial use.

Perceptions of antimicrobial usage, antimicrobial resistance and policy measures to reduce antimicrobial usage in convenient samples of Belgian, French, German, Swedish and Swiss pig farmers.

We conducted a survey among convenient samples of pig farmers (N=281) in Belgium, France, Germany, Sweden and Switzerland. We identified some significant differences among the five investigated countries (independent variable) regarding farmers' antimicrobial usage compared to their own country and worries related to pig farming (dependent variables), but most of the differences were rather small. In general, farmers perceived their own antimicrobial usage to be lower than that of their peers in the same country and lower than or similar to that of farmers from other countries. This may be a consequence of our convenience sample, resulting in self-selection of highly motivated farmers. Farmers were significantly more worried about financial/legal issues than about antimicrobial resistance. They believed that a reduction in revenues for slaughter pigs treated with a large amount of antimicrobials would have the most impact on reduced antimicrobial usage in their country. Further, farmers who were more worried about antimicrobial resistance and who estimated their own antimicrobial usage as lower than their fellow countrymen, perceived more impact from policy measures on the reduction of antimicrobials. Our results indicated that the same policy measures can be applied to reduce antimicrobial usage in pig farming in all five countries. Moreover, it seems worthwhile to increase pig farmers' awareness of the threat of antimicrobial resistance and its relation to antimicrobial usage; not only because pig farmers appeared little worried about antimicrobial usage but also because it affected farmers' perception of policy measures to reduce antimicrobial usage. Our samples were not representative for the national pig farmer populations. Further research is therefore needed to examine to what extent our findings can be generalised to these populations and to farmers in other countries.

Effect of a disinfection strategy on the methicillin-resistant Staphylococcus aureus CC398 prevalence of sows, their piglets and the barn environment.

AIMS: To assess, in a cleaned and disinfected barn environment, the efficacy of an animal disinfection strategy to reduce the livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) prevalence in sows, their offspring and the barn environment. METHODS AND RESULTS: On each farm, six sow rounds were sampled; sows were divided into either a test or control group. Per round, 20 sows and 40 of their piglets were sampled at different time points together with the barn environment. The disinfection strategy of the test groups consisted of washing the sows with a shampoo followed by disinfection of the skin with a solution containing chlorhexidine digluconate and isopropanol. On the first day of disinfection and 6 days after stopping the disinfection, a significant decrease (P < 0·01) of on average 68 and 66% in sow MRSA prevalence was observed on both farms, whereas no decrease was seen in the control groups. Just before weaning, 21-28 days after the end of the disinfection strategy, the difference in MRSA prevalence between both groups was reduced to 4% and no longer significant (P = 0·20). The MRSA prevalence of the piglets in the test groups was significantly lower (26%; P < 0·01) 6 days after the end of disinfection. Just before weaning, this difference was reduced to 5% but still significant (P < 0·01). In the swine nursery unit, no significant difference (P = 0·99) was seen between both groups. Based on semi-quantitative counts, a relationship (r(2)  > 0·6; P < 0·01) was seen between MRSA contamination in the barn environment and the MRSA prevalence in pigs. CONCLUSION: Results show that the tested disinfection strategy reduces temporarily the sow and piglet MRSA status, but does not result in a final reduction in MRSA at weaning or in the nursery unit. SIGNIFICANCE AND IMPACT OF THE STUDY: First report on the efficacy of an animal disinfection strategy to reduce LA-MRSA prevalence in sows, their offspring and the barn environment.

Assessment of human exposure to 3rd generation cephalosporin resistant E. coli (CREC) through consumption of broiler meat in Belgium.

Acquired resistance of Escherichia coli to 3rd generation cephalosporin antimicrobials is a relevant issue in intensive broiler farming. In Belgium, about 35% of the E. coli strains isolated from live broilers are resistant to 3rd generation cephalosporins while over 60% of the broilers are found to be carrier of these 3rd generation cephalosporin resistant E. coli (CREC) after selective isolation. A model aimed at estimating the exposure of the consumer to CREC by consumption of broiler meat was elaborated. This model consists of different modules that simulate the farm to fork chain starting from primary production, over slaughter, processing and distribution to storage, preparation and consumption of broiler meat. Input data were obtained from the Belgian Food Safety agencies' annual monitoring plan and results from dedicated research programs or surveys. The outcome of the model using the available baseline data estimates that the probability of exposure to 1000 colony forming units (cfu) of CREC or more during consumption of a meal containing chicken meat is ca. 1.5%, the majority of exposure being caused by cross contamination in the kitchen. The proportion of CREC (within the total number of E. coli) at primary production and the overall contamination of broiler carcasses or broiler parts with E. coli are dominant factors in the consumer exposure to CREC. The risk of this exposure for human health cannot be estimated at this stage given a lack of understanding of the factors influencing the transfer of cephalosporin antimicrobial resistance genes from these E. coli to the human intestinal bacteria and data on the further consequences of the presence of CREC on human health.

Cumulative exergy extraction from the natural environment (CEENE): a comprehensive life cycle impact assessment method for resource accounting.

The objective of the paper is to establish a comprehensive resource-based life cycle impact assessment (LCIA) method which is scientifically sound and that enables to assess all kinds of resources that are deprived from the natural ecosystem, all quantified on one single scale, free of weighting factors. The method is based on the exergy concept. Consistent exergy data on fossils, nuclear and metal ores, minerals, air, water, land occupation, and renewable energy sources were elaborated, with well defined system boundaries. Based on these data, the method quantifies the exergy "taken away" from natural ecosystems, and is thus called the cumulative exergy extraction from the natural environment (CEENE). The acquired data set was coupled with a state-of-the art life cycle inventory database, ecoinvent. In this way, the method is able to quantitatively distinguish eight categories of resources withdrawn from the natural environment: renewable resources, fossil fuels, nuclear energy, metal ores, minerals, water resources, land resources, and atmospheric resources. Third, the CEENE method is illustrated for a number of products that are available in ecoinvent, and results are compared with common resource oriented LCIA methods. The application to the materials in the ecoinvent database showed that fossil resources and land use are of particular importance with regard to the total CEENE score, although the other resource categories may also be significant.

Exergy-based efficiency and renewability assessment of biofuel production.

This study presents an efficiency and renewability analysis of the production of three biofuels: rapeseed methyl ester (RME), soybean methyl ester (SME) and corn-based ethanol (EtOH). The overall production chains have been taken into account: not only the agricultural crop production and the industrial conversion into biofuel, but also production of the supply of agricultural resources (pesticides, fertilizers, fuel, seeding material) and industrial resources (energy and chemicals) to transform the crops into biofuel. Simultaneously, byproducts of the agricultural and industrial processes have been taken into account when resources have to be allocated to the biofuels. The technical analysis via the second law of thermodynamics revealed that corn-based EtOH results in the highest production rate with an exergetic fuel content of 68.8 GJ ha(-1) yr(-1), whereas the RME and SME results were limited to 47.5 and 16.4 GJ ha(-1) yr(-1). The allocated nonrenewable resource input to deliver these biofuels is significant: 16.5, 15.4, and 5.6 MJ ha(-1) yr(-1). This means that these biofuels, generally considered as renewable resources, embed a nonrenewable fraction of one-quarter for EtOH and even one-third for RME and SME. This type of analysis provides scientifically sound quantitative information that is necessarywith respect to the sustainability analysis of so-called renewable energy.

Exergy analysis in the assessment of the sustainability of waste gas treatment systems.

This study focuses on the sustainability of different technological options for the treatment of waste gases from a waste water treatment plant loaded with volatile organic compounds. The options considered are biofiltration, active carbon adsorption and catalytic and thermal oxidation. The amount of resources and utilities to construct and operate each system have been investigated from the point of view of the Second Law of thermodynamics. The unit in which all resources are treated is Joules of exergy. It was concluded that biofiltration was the most exergetically efficient system. The cumulative exergy consumption of the resources and utilities for construction and operation have been quantified in exergy terms. Further on, the requirements for the abatement of emissions generated by operating the waste gas treatment systems and the amount of renewables have been taken into account in the assessment of the sustainability of the waste gas treatment technologies. Finally, a comparison between exergy analysis and life cycle analysis in assessing the sustainability of the waste gas treatment options, is presented.