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Le secteur de l’élevage est aujourd’hui confronté à une demande croissante de produits animaux à laquelle il doit répondre en limitant au maximum ses impacts environnementaux et en assurant sa durabilité. Parmi ces impacts, la pollution de l’air est une préoccupation majeure. Pour faire face au changement climatique et contribuer à l’amélioration de la qualité de l’air, les émissions de polluants atmosphériques et de gaz à effet de serre doivent être mieux caractérisées et maîtrisées afin de les prendre en compte dans l’évolution des pratiques d’élevage (alimentation, gestion des effluents, etc.). Des acteurs de la recherche et du développement se sont donc associés afin de développer une base de données appelée ELFE (ELevages et Facteurs d’Emission), compilant les valeurs publiées dans la littérature internationale des émissions d’ammoniac, de gaz à effet de serre, de particules et d’odeurs, sur toute la chaîne de gestion des effluents des élevages bovins, porcins et avicoles ainsi que leurs métadonnées associées. Parmi les 1 000 références bibliographiques collectées, environ 350 ont été intégrées à ce jour à la base de données, fournissant ainsi, un peu plus de 5 200 valeurs d’émission. La base de données ELFE permet de déterminer des moyennes d’émission associées à leurs écarts-types prenant en compte la diversité des systèmes d’élevage. Ces données pourront ainsi alimenter les inventaires nationaux d’émissions en proposant des facteurs d’émissions ajustés à des systèmes d’élevage définis et également, permettre d’évaluer la mise en place de pratiques de réduction des émissions. Cette base de données représente aussi une source d’information pour la réalisation d’évaluations multicritères permettant notamment, de préciser l’influence des métadonnées sur les niveaux d’émissions (climat, type de bâtiment, etc.). De plus, cette base propose une classification de chaque valeur d’émission en fonction du nombre de métadonnées renseignées dans les références bibliographiques (>50 % ; 30-50 %, The increasing demand for animal products is a major challenge for the livestock sector that must reduce its environmental impacts and ensure its sustainability. This sector has been identified as an important contributor to polluting gas emissions. Improving the knowledge on the origin and the magnitude of air pollutants and greenhouse gases emissions from livestock sector is essential to address climate change and to contribute to improve air quality with the evolution of breeding practices (feeding strategy, manure management, etc.). A consortium involving research and extension services partners was created to build a database called ELFE (ELevages et Facteurs d’Emission) with international data from literature references focusing on emissions of ammonia, greenhouse gases, particles and odors on the different steps of manure management of cattle, pig and poultry productions systems and their associated key variables. Around 350 publications (among 1 000 publications collected) are integrated into the database and provide more than 5 200 emission values. The ELFE database allows calculating average of emission and their standard deviation taking into account the diversity of livestock systems. These data can be used to provide emission factor for national inventories for specific livestock systems and also, to evaluate practices on gas emissions mitigation. This database can also be used to analyze the influence of key variables on the emission factor variability using multicriteria assessment (climate, building type, etc.). Moreover, this database propose a classification of emission factor into three classes according to the degree on which information about their most influential key variables was complete (>50 % ; 30-50 %

ELFE, a database to determine greenhouse gases and ammonia emissions factors from livestock. 20. Nitrogen Workshop. Coupling C-N-P-S cycles

Given the current scarcity of empirical data on ammonia (NH3) emissions from dairy cattle under different management -based mitigation techniques, a modeling approach to assess potential NH3 emission reduction factors is needed. This paper introduces a process-based model that estimates NH3 emission reduction factors for a dairy cattle barn featuring single or multiple management-based NH3 emission mitigation techniques, as compared to another barn, to which no mitigation measure is applied. The model accounts for the following emission mitigation measures: (a) floor scraping, (b) floor type, (c) floor flushing with water and (d) indoor acidification of manure. Model sensitivity analysis indicated that manure acidification was the most efficient NH3 emission reduction technique. A fair agreement was observed between reduction factors from the model and empirical estimates found in the literature. We propose a list of combinations of techniques that achieve the largest reductions. In order of efficiency, they are: (a) floor scraping combined with manure acidification (reduction efficiency 44-49%); (b) solid floor combined with scraping and flushing (reduction efficiency 21-27%); (c) floor scraping combined with flushing and (d) floor scraping alone (reduction efficiency 17-22%). The model is currently being used to advise the Flemish Government (Belgium), on the performance of certain NH3 emission reduction systems for dairy barns in Flanders.

Este estudo foi conduzido com o propósito de monitorar a emissão de amônia (NH3) de um galpão de frango de corte com ventilação mecânica e outro com ventilação natural (GVM e GVN, respectivamente) e, por fim, calcular seus fatores de emissão de NH3 (fNH3). A densidade de alojamento das aves foi 13.5 e 11.1 aves m-2 para o GVM e GVN, respectivamente. As aves foram removidas para o abate aos 43 dias e a cama consistiu de casca de café, em primeiro uso. As taxas de ventilação nos galpões foram calculadas com base no método do balanço de dióxido de carbono. Os valores de fNH3 obtidos foram 0.32 ± 0.10 e 0.27 ± 0.07 g ave-1 d-1 para o GVM e GVN, respectivamente, e estão de acordo com o que foi apresentado em outros estudos independentes, realizados em condições similares. O valor estimado de fNH3 em base anual foi 58 g ave-alocada-1 ano-1. Concluiu-se que o tipo de sistema de ventilação adotado em cada galpão não afetou, de modo significativo, a parametrização da equação de emissão no processo de modelagem. Os resultados validam a acurácia da metodologia de determinação da emissão de amônia para galpões nas condições brasileiras e contribuem para a formação de base de dados confiável de fatores de emissão em climas tropicais, quando aplicada em um número suficiente de galpões que seja representativo do cenário brasileiro. This study was conducted with the aim of monitoring NH3 emissions from a mechanically and a naturally ventilated broiler house (MVB and NVB, respectively) and calculate their ammonia emission factors (fNH3). Bird stocking density was 13.5 and 11.1 birds m-2 for the MVB and NVB, respectively. The marketing age was 43 days and bedding consisted of dried coffee husks in its first time of use. Ventilation rates were calculated with the metabolic carbon dioxide mass balance method. Values of fNH3 were 0.32 ± 0.10 and 0.27 ± 0.07 g bird-1 d-1 for the MVB and NVB, respectively, and are in agreement to what was presented in other studies performed under similar conditions. The fNH3 estimated on yearly basis was 58 g bird-place-1 year-1. It was concluded that the different types of ventilation system between the studied broiler barns did not significantly affect emissions in the modeling process. The results obtained help providing reliable methodology for the determination of a solid database on NH3 emission factors for tropical conditions that can be used for future inventories, when performed in a sufficient number of barns that is representative for the Brazilian scenario.

The low efficiency of nitrogen (N) intake in dairy cows can increase feed costs and ammonia emissions. At the rumen level, decreasing degradable N to improve the urea reuse in microbial protein synthesis, can increase N efficiency (Neff=Nmilk/Nintake). Moreover, at the animal level, the metabolisable protein (MP) efficiency varies greatly between dairy cows. Applying precision feeding, with adjustment of the diet according to individual observations, could increase this MPeff. The objective of this study was to improve both N and MP efficiencies by combining a reduction in rumen degradable protein (RDP, factor N) with an individual adjustment of MP content in the diet (factor E) in a 2×2 factorial design with 4 groups of 11 cows for 12 weeks fed maize-based diet. Factor N was either at the reference level of INRA for RDP (N0) or at a reduced level (N-10) of -1.4 g of degradable protein per MJ of net energy for lactation (NEL). Factor E was either constant with 14.8 g of MP per MJ NEL (EC), or variable (EV), from 12.0 to 15.5 g MP/ MJ NEL and calculated for each cow according to its MPeff on a 4-week reference period. The lower the efficiency was, the lower the applied MP/NEL ratio was. No interaction occurred between the 2 factors. The decrease in RDP had no significant effect on intake and production. The milk production of EV was 1.7 kg/ day lower than EC, but the energy ef¿ ciency (kg of milk/kg of DMI) was unchanged. The RDP reduction improved Neff (35.7 vs 32.2%) and individual protein feeding mainly improved MPeff (69.1 vs 59.3%). Between extreme treatments (N0_EC vs N-10_EV), crude protein content decreased from 14.9 to 12.5%, Neff varied from 32.1% to 36.4%, and estimated urine urea-N excretion was reduced by 56%. Reducing degradable N content of the diet and applying precision feeding to dairy cows fed indoors is thus a way to better use proteins and to reduce ammonia emissions.

Moisture content (Psi) of poultry manure or litter is an important property of the material. Relating manure or litter Psi to its ammonia (NH3) emission is conducive to assessing and/or controlling real-time ammonia emissions from the manure or litter. However; means to measure manure or litter on a real-time basis is lacking. This study was carried out to characterize the operational performance of a commercially available soil moisture sensor for measuring V of meat-bird (broiler and turkey) litters and laying-hen manure. The Psi tested ranged from 27.1% to 65.7% for broiler litter, 22.8% to 56.1% for turkey litter, and 11.0% to 75.0% for layer manure. Bulk density (rho) ranged from 318 to 468 kg m(-3) (20 to 29 lb ft(-3)) for the broiler and turkey litters and from 151 to 943 kg m(-3)(9 to 55 lb ft(-3)) for laying-hen manure. Linear regression equations were developed to relate the sensor output to Psi and rho for the meat-bird litters and to Psi for the laying-hen manure, all yielding good fit (R-2=0.95 -0.99). An uncertainty analysis performed on the developed calibration equations revealed average errors in the V estimation of +/- 7.1% estimated value for the poultry litters and +/- 6.7% estimated value for the laying-hen manure. Litter temperature was found to have a small impact on Psi measurement by the sensor, 0.31% of measured mV per degrees C (0.17% per degrees F) deviation from the mean operating temperature over the range of 4 degrees C to 24 degrees C (39 degrees F to 75 degrees F). Results of the study indicate that when properly calibrated, the soil moisture sensor offers a reasonable means for real-time measurement of poultry litter or manure moisture content.

A great deal of effort has been given through intensive research toward studying the sources of gaseous emissions from animal feeding operations (AFOs) and their influencing factors. Ammonia (NH3) is the most predominant noxious gas released from poultry production facilities and it is mainly affected by diet composition, manure temperature, moisture content and stacking configuration and manure surface area exposed to ambient air. However, current literature lacks information on bird age effects on NH3 emissions, even though changes in diet composition with bird age are expected to affect the emissions. Also, some producers have been using different bird stocking densities (SD) as an attempt to improve bird welfare. Nevertheless the effects of different bird SD regimens on NH3 emissions remain unknown. Moreover, it has been shown that different housing styles can have significant impacts on the magnitude of NH3 emissions from laying-hen facilities in that the high rise (HR) systems (typical of US egg production) emit 61 to 71 % more ammonia than the manure-belt (MB) systems (gaining more popularity in the US). The impact of manure accumulation time on the belts in MB systems on NH3 emissions needs to be quantified. Hence, a research study was conducted in a laboratory setting that resembled a commercial MB system for laying hens. The results of the study are presented in this thesis. Chapter 2 describes the effect of different SD regimens (155 to 619 cm2 bird-1 or 24 to 96 in2 bird-1) and manure accumulation time (MAT, 1 to 6 d) of pullets (hens < 18 weeks of age) and laying hens on NH3emissions. Results showed that daily NH3 emission rate (ER) for pullets and laying hens increased exponentially with bird age and MAT, while SD effect on NH3 ER was more pronounced for MAT ≥ 3d (P