Poster. Straw bedding systems are preferred by consumers because they are expected to provide better welfare for pigs and reduce odour nuisance. Nevertheless, the development of this way of raising pigs could be limited by the low availability of straw which is primarily used in beef and cattle productions. Reducing the amount of straw per pig is a simple way to contribute to solving this problem of straw availability. The aim of this study was to determine the impact of a 33% reduction in straw used for bedding on ammonia, GHG and odour emissions. Two successive batches of fattening pigs were grouped in three identical rooms which only differed in the frequency and amount of straw supplied for litter. In the first room (RR), the total quantity of straw for the whole period was fixed at 90 kg per pig. In the second and third room (R33 and R33F), the quantity of straw was reduced by 33% (60 kg per pig). In RR and R33, straw was added every two weeks until 65 kg and weekly after; whereas in R33F, straw was added each week. The reduction in the amount of straw did not induce deterioration in animal performance and in carcass characteristics. Concerning ammonia and odours, the main effect of the reduction of straw was the increase in emissions and the increased dirtiness of the litter, especially for R33. The increase of ammonia and odour emissions appeared to be less important for R33F than for R33. Replenishing litter on a weekly basis is a good way of limiting the negative effects caused by the reduction of straw used per pig.

The environmental impact assessment of the agricultural activities is justifiable, but it’s a subject under development; some methodological points staying debate there. So, in the framework of a French project of displaying of these impacts to the consumer, this study investigated a particular point of the method of carbon impact calculation, up to now weakly approached: the allowance of the upstream impacts between the various parts of the animal , after slaughtering. Six different animal species have been investigated. The objective analysis of the various keys of allowance led to recommend the use of the mass allowance by dry material. Other goal of the study is to determine a functional unit according to which will be represented the environmental impact to the consumer. A nutritional functional unit was built and tested on several foodstuffs. It turns out that it represents an objective alternative to the mass because it takes into account the specific function of the food.

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This study aims to produce multicriteria environmental figures (using Life Cycle Assessment, LCA) associated with socioeconomic indicators for different types of pig units representative of the main French production standards. Eight systems are assessed, defined by their size, the degree of specialization and the location of the pig unit, the slurry management and the pig feeding strategy. The results are expressed per kilogram live pig produced at the farm level, and the field for Life Cycle Analysis includes production and supply of inputs, construction of buildings, pig breeding and management of slurry. These reference standards provide a picture of the socioeconomic and environmental performance of French pig production systems and of their variability between and within systems. The environmental results make it possible to identify the most strategic and easily attainable options of improvement. The efficiency of different strategies is evaluated in connection with feed formulation, improvement of animal performance, and the implementation of recommended good environmental practices. The socioeconomic indicators show the various levels of access to the action levers.

A joint project was conducted for over three years on the diagnostics and solutions for limiting the transfer of agricultural phosphorous to water bodies. Agronomic phosphorous balances were calculated at the departemental level, and in Brittany where soils keep accumulating phosphorous, at the canton level too. At the livestock farm level, two main means of reducing excess phosphorous were demonstrated as being relevant: reducing mineral fertilization and improving feeding (particularly by decreasing the amount of phosphorous in mineral complements and providing phytases). At the plot level, data from field stations showed that (i) the transfer of phosphorous by runoff and drainage increased in soils enriched in phosphorous and/or when organic fertilization was applied, (ii) in drained plots, more phosphorous was lost when tillage was suppressed because of the preservation of preferential drainage channels such as worm burrows. Finally, the comparison between two watersheds highlighted the importance of protecting riverbanks for reducing the loss of phosphorous.
Solutions were proposed at each level for reducing the sources of phosphorous and associated diffuse transfers.

The Economic Interest Grouping farm of Villefranche Grand Sud (farrow-to-finish operator with 140 sows) is equipped with 1200 m² of reed-planted beds for dehydrating the mud from the biological treatment of pig slurry. The full-scale implementation of separation in phases in reed-beds has made it possible to demonstrate that this technique has been mastered. The mud from these beds (19% dry matter) is then composted either with milled green waste or with cow manure low in straw content.
Experimentally, several windrows of different concentrations were erected. In order for composting to occur, there must be an addition of green waste of over 30%. Cow manure low in straw content did not prove to be a good cosubstrate. Additional studies are needed to obtain compost in conformity with standard NFU 44051 standard.
The use of other cosubstrates must also be studied.

Cleaning with a medium-pressure nozzle (Fitjet® nozzle, 40 bars) was compared to conventional cleaning at high pressure with a rotary nozzle (160 bars), based on criteria such as working time, water consumption, cost, difficulty of work and cleaning efficiency.
The results suggest that the cost is similar and the cleaning score with contact plates is correct for both nozzles. Concerning the difficulty of work, the results favour the Fitjet® nozzle: the noise level is significantly lower, the visibility during washing is significantly higher, musculoskeletal disorders are lessened, projections towards the operator’s face are significantly reduced and cleaning is considered less difficult and less tiring for the operator.

Two experiments were carried out to determine the influence of bowl drinker flow rate on water consumption and wastage by growing-finishing pigs. The first trial involved two batches of 200 weaned piglets (9-24 kg). In the second trial, two batches of 96 growing-finishing pigs (33-112 kg) were studied. For each trial, two treatments were compared: a flow rate of 1 l/min (FR1) or a flow rate of 2 l/min (FR2). Average water wastage was 20 % of total water consumption during post weaning period and 14 % for growing-finishing pigs. Increased drinker flow rate induced higher water ingestion during both the 8-25 kg period (+68%) and the finishing period (+ 16 %). There was no effect of treatment on animal performance.

Cleaning with a medium-pressure nozzle (Fitjet® nozzle, 40 bars) was compared to conventional cleaning at high pressure with a rotary nozzle (160 bars), using criteria such as working time, water consumption, cost, difficulty of work and cleaning efficiency. The results obtained for the two types of nozzles suggest that the cost is almost the same and that the cleaning score, measured with contact plates, was good. Concerning the difficulty of work, results favoured the medium pressure nozzle; the noise level was significantly lower; the visibility during washing was significantly improved; musculoskeletal disorders were lessened; debris splashback into the operator’s face was significantly reduced and cleaning was considered less painful and less tiring for the operator.

Levels of GHG and ammonia emissions can be determined by continuously measuring concentrations in barn rooms during the entire fattening period. However, the high investment of time and money required by this method limit its widespread application; practically, it would be difficult to justify its use to assess the variability in emissions attributable to housing system, farming practices and climate in a large number of facilities. A simpler and reliable method was needed to assess the variability and develop appropriate mitigation strategies. With that objective in mind, and for two consecutive seasons, NH3, N2O, CO2, CH4 and water vapor were continuously measured during the entire fattening period. The pigs were reared from 30 to 110 kg on a fully slatted floor. To help validate the simplified method, a comparison of emissions measured in both batches with the nitrogen and carbon mass balances deficit was achieved and showed that 85 and 105% of total nitrogen and carbon losses were explained by measured gaseous emissions. Based on the emission kinetics obtained during continuous measurements, emissions were calculated using the concentrations ratios method. This method was based on carbon losses deduced from carbon mass balance combined with mean gas concentrations ratios obtained with spot measurements during the rearing period. Finally, results showed that intermittent gas concentrations measurements performed between 10 a.m. and 16 p.m. on days 25, 60 and 80 of fattening led to estimates of emission levels with an error less than 20%. Additional batches were used to validate this simplified method.

The environmental assessment of farming systems has become an important issue to define the future of livestock with more efficient and environmentally friendly systems. To better evaluate these systems and their possible evolutions, the model MELODIE was developed. Based on a generic architecture coupling decision and biotechnical sub-models, MELODIE enables the simulation of very different livestock farming systems. It compares different scenarios of farm management and evaluates themusing the same farm structure and pedo-climatic context. The many possibilities of model outputs make it an interesting tool for virtual experimentation on farming systems, complementary to experimental design or farms survey.

Methanization is not, strictly speaking, a treatment solution, but the co-generation industry can nevertheless provide its input by dehydrating a fraction of the digestate ahead of export. We led an economics analysis on 4 process protocols coupling dehydration with a methanization unit. Scenarios were built around two digestate volume targets for dehydration (3000 and 10000 m3/yr) and three surplus levels (20, 50 and 80%). The results highlight that scenarios employing a drier-conveyor appear most profitable in most of the settings studied, except (1) for larger-scale methanization units working at 80% surplus, where the heat deficit makes it necessary to employ an expensive add-on boiler requiring heavy investment and fuel-cost outlays,
making it economically more profitable to use multi-stage evaporator-concentrators; (2) for smaller-scale methanization units working at 80% surplus, where no scenario proved profitable. This paper underlines that technical factors (type of co-product obtained, equipment technology, etc.) also need to be integrated when selecting a process protocol.

Continuous measurements of ammonia and greenhouses gases were achieved on exhaust air from two fattening rooms differing by the type of floor (totally slatted floor vs. partially slatted floor) and the ambient temperature. Temperature was regulated at 18°C in the room with partially slatted floor (room PSF18) and 24°C in the room with fully slatted floor (FSF24). Pigs were fed ad libitum. Daily feed intake, growth rate and carcass backfat thickness were significantly higher for PSF18 pigs than for FSF24 ones, corresponding to a higher feed conversion ratio for PSF18 pigs.
Under cold conditions (18°C), the N-NH3, N-N2O, C-CH4 and C-CO2 daily emissions per pig on partially slatted floor were similar to those on fully slatted floor under thermoneutral conditions (FSF24: 8.9–0.12-7.3 and 676 g, PSF18: 9.1–0.15-8.4 and 629 g/pig, respectively). A further reduction of ammonia emission from pig units on partially slatted floor would require a more pronounced reduction of ambient temperature. However, in such conditions, a deterioration of feed conversion ratio and carcass leanness may be expected. Thus, the extra-cost induced by the utilization of partially slatted floor in cold ambient conditions would not be acceptable with regard to the definition of Best Available Techniques given by the IPPC directive.

A mathematical model was developed from literature data to predict the volume and composition of pig’s excreta (dry and organic matter, C, N, P, K, Cu and Zn contents), and the emission of greenhouse gases (CH4 and CO2) though respiration and from the intestinal tract, for each physiological stage (post-weaning and fattening pigs and lactating and gestating sows). The main sources of variation considered in the model are related to animal performances (feed efficiency, prolificacy, body weight gain, etc.), to water and nutrient intakes and to housing conditions (ambient temperature). Model predictions were validated by using 19 experimental studies, most of them performed in conditions close to those of commercial farms. Validation results showed that the model is precise and robust when predicting slurry volume (R2 = 0.96), slurry N (R2 = 0.91), P (R2 = 0.95) and to a lesser extent dry matter (R2 = 0.75) contents. Faeces and urine composition (minerals and macronutrients) can also be precisely assessed, provided the composition and the digestibility of the feed are well known. Sensitivity analysis showed strong differences in CH4 emission and excretion amounts and composition according to physiological status, animal performance, temperature and diet composition. The model is an efficient tool to calculate nutrient balances at the animal level in commercial conditions, and to simulate the effect of production alternatives, such as feeding strategy or animal performance, on excreta production and composition. This is illustrated by simulations of three feeding strategies, which demonstrates important opportunities to limit environmental risks through diet manipulations.

Since the early 1990s, there has been a surge in the number of different membrane filtration trials led on piggery wastes. Most of these trials have been led at lab scale, but there are examples of trials led at farm scale. Nanofiltration, and logically speaking reverse osmosis, aggregate together the soluble nutrients, including ammonia nitrogen and salts, so that they can be affordably transported outside the surplus-producing zone. This review begins by recapping the principles of membrane filtration before reviewing the clogging issue, which is the main problem arising when implementing these processes, and the solutions imposed:
pre-treatments and scrubbing procedures. It is equally important to understand and address the volume reduction factor, which impacts not just processing costs but also the costs involved in transporting the nutrients.
Finally, ammonia nitrogen, which is one of the more specific components of animal waste, is more complex to handle due to its atypical behaviour profile.
This review highlights that membrane filtration-based separation techniques are recognized as effective, reliable, and easy to implement, but more difficult to correctly scale and finalize. Clogging remains hard to avoid, difficult to reduce, and complex to analyze.

The study tested the use of dynamic floating chambers to measure emissions factors of ammonia (NH3), nitrous oxide (N2O) methane (CH4) and carbon dioxide (CO2) from stored pig slurry and measured the variations of the emissions in time and space.
In 2006, dynamic floating chambers were used for the continuous measurement of gaseous emissions from two experimental tanks filled with fattening pig slurry stored for two summer months and in a pit filled repeatedly with mixed slurry between October and March. To check the influence of air speed on gaseous emissions, each tank was fitted with a chamber : one operating with an air speed at the surface of the slurry of 0.01 m/s, the other with a speed of 1 m/s. To ascertain the spatial variability of the emissions, two identical chambers were used for the pit : one was regularly displaced across the surface of the slurry ; the other was fixed throughout the storage period. The measurements obtained were compared with the nitrogen and carbon input-output mass balances of the slurry. The results indicated that the measured gaseous emissions explained 4 to 38% of the total nitrogen losses and 61 to 285% of the total carbon losses. The use of such dynamic floating chambers is not an appropriate method to evaluate the gaseous emission factors from slurry storage. The kinetics of the emissions underline the importance of measurement periods and their duration to measure emission factors.

With the intensification of European regulation on atmospheric pollution, reduction of ammonia emitted by pig units become a priority for farmers. Conflicts between pig farmers and neighbourhood are generally based on odours emissions. The part of buildings in ammonia produced by pig production is estimated of 60% of the whole ammonia emitted. For odours, this part is around 70%. Sows and the rearing of piglets until 30 kg represent less than 30% of ammonia and around 40% of odours emitted by the building. Focus the means of reduction of ammonia and odours produced by rooms housing grower-finisher pigs appears to be a great way to decrease the whole quantity of ammonia and odours emitted by a pig farm. Nowadays, in pig production, the implementation of wet scrubber is probably the only means to reduce both. Wet scrubber equipment in pig production has a great development but several types of scrubber are proposed to farmers who not really know what are the main criteria illustrating the optimal efficiency of scrubbers on ammonia and odours. The aim of this article is to synthesise these main criteria based on studies achieved on experimental stations and on commercial units equipped with different kind of wet scrubbers. The incidence of some technical parameters of wet scrubber conception – volume, air and water flow rate - are illustrated on the efficiency on ammonia, odours and dust reduction. Global results of various types of wet scrubber are presented and their efficiency on ammonia, odours and dust emissions are showed in relation with season and physiological stages. In a last part, an economic comparison is realized between wet scrubbers and others ways of reduction proposed at present to pig farmers

Technical institutes have drafted a methodological guide called "GES’TIM" for estimating the impact of agriculture on greenhouse gas (GHG) emissions.
The implementation of this method has provided an evaluation of the carbon footprint of French pig breeding (up to the farm gate) at 2.69 ± 0.4 kg CO2eq/kg pig liveweight, by identifying the main emission sources (direct emission of effluents and indirect emissions through food). This work has also revealed sources of inaccuracy in evaluation (through lack of references or because of high uncertainty in available values) and pinpoints the sources that are most sensitive in this respect. Additional work will now be needed to consolidate these references. This need is seen in several current projects, e.g., environmental labelling of consumer items provided for by the National Consensus on the Environment (planned for early 2011) and the carbon tax. The challenge this work must meet is to give the pork industry a set of values representative of the French production context, and that are sensitive to the diversity of pig breeding practice and possible directions for further progress.

The study tested the use of dynamic floating chambers to measure emissions factors of ammonia (NH3), nitrous oxide (N2O) methane (CH4) and carbon dioxide (CO2) from stored pig slurry and measured the variations of the emissions in time and space.
In 2006, dynamic floating chambers were used for the continuous measurement of gaseous emissions from two experimental tanks filled with fattening pig slurry stored for two summer months and in a pit filled repeatedly with mixed slurry between October and March. To check the influence of air speed on gaseous emissions, each tank was fitted with a chamber : one operating with an air speed at the surface of the slurry of 0.01 m/s, the other with a speed of 1 m/s. To ascertain the spatial variability of the emissions, two identical chambers were used for the pit : one was regularly displaced across the surface of the slurry ; the other was fixed throughout the storage period. The measurements obtained were compared with the nitrogen and carbon input-output mass balances of the slurry. The results indicated that the measured gaseous emissions explained 4 to 38% of the total nitrogen losses and 61 to 285% of the total carbon losses. The use of such dynamic floating chambers is not an appropriate method to evaluate the gaseous emission factors from slurry storage. The kinetics of the emissions underline the importance of measurement periods and their duration to measure emission factors.

Poster. Alternative solution of pig corpses management could be the bio-digestion. Corpses were stored in a tank with hot water (38°C) for two periods (3 months each). Air extracted from the tank was treated with a biofilter combined with activated charcoal in a chimney. A global study was achieved on technical aspects of this alternative method but this article focused only on gaseous and odorous emissions. GC-MS and GC-sniffing were applied with olfactometric analysis on air samples taken during the whole study (6 months) from the exit of the tank, just after the biofilter and after the unit of activated charcoal. On the air samples taken from the tank, odour concentration was very high (109 odour units/m3) but it decreased until the end of the study to 105 odour unit/m3. Considering odours emitted to the atmosphere, levels varied around 103 odour units/m3 showing the great efficiency of the air treatment. Ammonia concentrations were around 500 ppm at the exit of the tank, and only 5 ppm in the air exhausted to the atmosphere. Some sulphurous compounds such as DMDS (DiMethyl DiSulfur) appeared to have a great incidence on odours emissions. A positive correlation was found between the concentration of DMDS in the air and the level of odours emissions.
This correlation was established on the air extracted from the tank or emitted to the atmosphere. Although the bio-digestion could be an alternative for an efficient management of corpses on commercial farms, it wouldn’t be possible to install it without air treatment.

The pork production industry faces a number of environmental challenges, and there is pressure on pig farms to internalize how environmental externalities are managed by deploying environmental management tools. A set of 9 pig barn performance indicators has been put forward. The rationale is to enable individual pig farms to run controls on their performance while enabling a network of farms to pool the results (thereby building a ‘reference framework’). These indicators measure direct consumption (water, energy) and emissions (NH3, greenhouse gases, and smells) and gauge output of excretions (N, P2O5, Cu and Zn) and waste, with the results quantified in kg/pig produced. The indicators are based on in-farm data and existing technical-economic methods of analysis. Results from 7 farms employing the indicator system demonstrated high inter-farm and intra-farm sensitivity, which is an advantage over straightforward averaged-out references. Certain indicators do require the deployment of measurement systems adapted to pig-farm settings in order to yield good-quality assessments. Studies are currently underway to launch a pilot network, which will work with actors from the sector to exploit the lessons learned.

This paper summarises the contributions made by the «Porcherie verte» programme in the overall integrated evaluation of pig production systems, considering on different scales the different pertinent aspects of sustainability, beyond environmental impact. The multiple criteria comparison of two types of breeding management considers all the aspects of sustainability (environment, society, economy) but at a level restrained to pig breeding. Pigs raised on litter with access to a small courtyard have better welfare, better growth performances but with fatter carcasses than pigs raised on wood slats. Their meat has a poorer technological quality but a better sensorial quality.
This type of management produces less unpleasant odours but is more costly. The products can, however, be better valorised by a label.
Modelling aimed at optimisation of a farm considers the environmental and economic aspects, but not those of society, when comparing the different ways to manage waste. The scale of the approach is larger than in the preceding study, considering the interactions between animal and plant production on the farm’s property, which corresponds to a fundamental decision scale in agriculture. The «raw manure» waste management leads to an improved gross margin, with good environmental balance, but the production is limited to 60 pigs per hectare. The biological treatment of manure without phase separation allows increasing pig production but deteriorates the phosphorus balance of the farm and significantly reduces the gross margin per pig produced. Phase separation before biological treatment of manure allows an increased pig production that respects environmental phosphorus constraints, but it decreases the gross margin per pig produced.
Manure composting can be an alternative to biological treatment for small farms, but its environmental balance is poor. Exporting manure compost slightly improves the apparent N and P balances of the farms but does not change gas emissions. It allows maintaining good gross emissions, even with high numbers of animals. Pig breeding on litter allows the production of more pigs/ha but is unfavourable for the environmental impact and increases production costs. Composting litter manure increases pig production per ha but only in the absence of environmental constraints on phosphorus and the growth of the gross margin is low. Exporting the compost surplus allows increasing pig production by lowering the apparent N and P balances, but not gas emissions. Biological treatment seems to give the best compromise between gross margin and environmental impact amongst the different types of treatment that allow a large number of animals, as long as one does not consider the impact of transfers outside of the farm. Amongst the different types of treatment with exportation that allow very high population levels, the composting of manure seems to cumulate the disadvantages in terms of gross margin and environmental impacts, if one neglects the impact of transfers outside of the farm associated with biological treatment.
The global evaluation of environmental impact of pig farms is restrained to the environmental aspects but its scale of approach integrates all the impacts associated with the processes upstream of the farm. The analysis of the life cycle (ACV) is a method of choice to do this evaluation and was developed for the comparison of the environmental impacts of the three contrasted scenarios of pig production. The most intensive production according to the scenario of good agricultural practices has the lowest impact on climate change, but the highest impact on acidification. Biological production that is not intensive uses a large surface but has a lower impact on eutrophisation.
Generally, the best compromise between production costs and environmental respect are obtained by the most economic systems in terms of surface, which uses the soil’s capacities the best to produce feed for animals and receive their waste. The absence of a link to soil is expensive and has a high impact on ecology.