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- ItemUncertainty in the measurement of indoor temperature and humidity in naturally ventilated dairy buildings as influenced by measurement technique and data variability(Amsterdam : Elsevier, 2017) Hempel, Sabrina; König, Marcel; Menz, Christoph; Janke, David; Amon, Barbara; Banhazi, Thomas M.; Estellés, Fernando; Amon, ThomasThe microclimatic conditions in dairy buildings affect animal welfare and gaseous emissions. Measurements are highly variable due to the inhomogeneous distribution of heat and humidity sources (related to farm management) and the turbulent inflow (associated with meteorologic boundary conditions). The selection of the measurement strategy (number and position of the sensors) and the analysis methodology adds to the uncertainty of the applied measurement technique. To assess the suitability of different sensor positions, in situations where monitoring in the direct vicinity of the animals is not possible, we collected long-term data in two naturally ventilated dairy barns in Germany between March 2015 and April 2016 (horizontal and vertical profiles with 10 to 5 min temporal resolution). Uncertainties related to the measurement setup were assessed by comparing the device outputs under lab conditions after the on-farm experiments. We found out that the uncertainty in measurements of relative humidity is of particular importance when assessing heat stress risk and resulting economic losses in terms of temperature-humidity index. Measurements at a height of approximately 3 m–3.5 m turned out to be a good approximation for the microclimatic conditions in the animal occupied zone (including the air volume close to the emission active zone). However, further investigation along this cross-section is required to reduce uncertainties related to the inhomogeneous distribution of humidity. In addition, a regular sound cleaning (and if possible recalibration after few months) of the measurement devices is crucial to reduce the instrumentation uncertainty in long-term monitoring of relative humidity in dairy barns. © 2017 The Authors
- ItemA Parametric Model for Local Air Exchange Rate of Naturally Ventilated Barns(Basel : MDPI AG, 2021) Doumbia, E. Moustapha; Janke, David; Yi, Qianying; Prinz, Alexander; Amon, Thomas; Kriegel, Martin; Hempel, SabrinaWith an increasing number of naturally ventilated dairy barns (NVDBs), the emission of ammonia and greenhouse gases into the surrounding environment is expected to increase as well. It is very challenging to accurately determine the amount of gases released from a NVDB on-farm. Moreover, control options for the micro-climate to increase animal welfare are limited in an NVDB at present. Both issues are due to the complexity of the NVDB micro-environment, which is subject to temporal (such as wind direction and temperature) and spatial (such as openings and animals acting as airflow obstacles) fluctuations. The air exchange rate (AER) is one of the most valuable evaluation entities, since it is directly related to the gas emission rate and animal welfare. In this context, our study determined the general and local AERs of NVDBs of different shapes under diverse airflow conditions. Previous works identified main influencing parameters for the general AER and mathematically linked them together to predict the AER of the barn as a whole. The present research study is a continuation and extension of previous studies about the determination of AER. It provides new insights into the influence of convection flow regimes. In addition, it goes further in precision by determining the local AERs, depending on the position of the considered volume inside the barn. After running several computational fluid dynamics (CFD) simulations, we used the statistical tool of general linear modeling in order to identify quantitative relationships between the AER and the following five influencing parameters, the length/width ratio of the barn, the side opening configuration, the airflow temperature, magnitude and incoming direction. The work succeeded in taking the temperature into account as a further influencing parameter in the model and, thus, for the first time, in analysing the effect of the different types of flow convection in this context. The resulting equations predict the barn AER with an R2 equals 0.98 and the local AER with a mean R2 equals around 0.87. The results go a step further in the precise determination of the AER of NVDB and, therefore, are of fundamental importance for a better and deeper understanding of the interaction between the driving forces of AER in NVDB.
- ItemParticulate Matter Dispersion Modeling in Agricultural Applications: Investigation of a Transient Open Source Solver(Basel : MDPI, 2021) Janke, David; Swaminathan, Senthilathiban; Hempel, Sabrina; Kasper, Robert; Amon, ThomasAgriculture is a major emitter of particulate matter (PM), which causes health problems and can act as a carrier of the pathogen material that spreads diseases. The aim of this study was to investigate an open-source solver that simulates the transport and dispersion of PM for typical agricultural applications. We investigated a coupled Eulerian–Lagrangian solver within the open source software package OpenFOAM. The continuous phase was solved using transient large eddy simulations, where four different subgrid-scale turbulence models and an inflow turbulence generator were tested. The discrete phase was simulated using two different Lagrangian solvers. For the validation case of a turbulent flow of a street canyon, the flowfield could be recaptured very well, with errors of around 5% for the non-equilibrium turbulence models (WALE and dynamicKeq) in the main regions. The inflow turbulence generator could create a stable and accurate boundary layer for the mean vertical velocity and vertical profile of the turbulent Reynolds stresses R11. The validation of the Lagrangian solver showed mixed results, with partly good agreements (simulation results within the measurement uncertainty), and partly high deviations of up to 80% for the concentration of particles. The higher deviations were attributed to an insufficient turbulence regime of the used validation case, which was an experimental chamber. For the simulation case of PM dispersion from manure application on a field, the solver could capture the influence of features such as size and density on the dispersion. The investigated solver is especially useful for further investigations into time-dependent processes in the near-source area of PM sources.
- ItemHeat stress risk in European dairy cattle husbandry under different climate change scenarios – uncertainties and potential impacts(Göttingen : Copernicus, 2019) Hempel, Sabrina; Menz, Christoph; Pinto, Severino; Galán, Elena; Janke, David; Estellés, Fernando; Müschner-Siemens, Theresa; Wang, Xiaoshuai; Heinicke, Julia; Zhang, Guoqiang; Amon, Barbara; del Prado, Agustín; Amon, ThomasIn the last decades, a global warming trend was observed. Along with the temperature increase, modifications in the humidity and wind regime amplify the regional and local impacts on livestock husbandry. Direct impacts include the occurrence of climatic stress conditions. In Europe, cows are economically highly relevant and are mainly kept in naturally ventilated buildings that are most susceptible to climate change. The high-yielding cows are particularly vulnerable to heat stress. Modifications in housing management are the main measures taken to improve the ability of livestock to cope with these conditions. Measures are typically taken in direct reaction to uncomfortable conditions instead of in anticipation of a long-term risk for climatic stress. Measures that balance welfare, environmental and economic issues are barely investigated in the context of climate change and are thus almost not available for commercial farms. Quantitative analysis of the climate change impacts on animal welfare and linked economic and environmental factors is rare. Therefore, we used a numerical modeling approach to estimate the future heat stress risk in such dairy cattle husbandry systems. The indoor climate was monitored inside three reference barns in central Europe and the Mediterranean regions. An artificial neuronal network (ANN) was trained to relate the outdoor weather conditions provided by official meteorological weather stations to the measured indoor microclimate. Subsequently, this ANN model was driven by an ensemble of regional climate model projections with three different greenhouse gas concentration scenarios. For the evaluation of the heat stress risk, we considered the number and duration of heat stress events. Based on the changes in the heat stress events, various economic and environmental impacts were estimated. The impacts of the projected increase in heat stress risk varied among the barns due to different locations and designs as well as the anticipated climate change (considering different climate models and future greenhouse gas concentrations). There was an overall increasing trend in number and duration of heat stress events. At the end of the century, the number of annual stress events can be expected to increase by up to 2000, while the average duration of the events increases by up to 22 h compared to the end of the last century. This implies strong impacts on economics, environment and animal welfare and an urgent need for mid-term adaptation strategies. We anticipated that up to one-tenth of all hours of a year, correspondingly one-third of all days, will be classified as critical heat stress conditions. Due to heat stress, milk yield may decrease by about 2.8 % relative to the present European milk yield, and farmers may expect financial losses in the summer season of about 5.4 % of their monthly income. In addition, an increasing demand for emission reduction measures must be expected, as an emission increase of about 16 Gg of ammonia and 0.1 Gg of methane per year can be expected under the anticipated heat stress conditions. The cattle respiration rate increases by up to 60 %, and the standing time may be prolonged by 1 h. This causes health issues and increases the probability of medical treatments. The various impacts imply feedback loops in the climate system which are presently underexplored. Hence, future in-depth studies on the different impacts and adaptation options at different stress levels are highly recommended.
- ItemAirborne bacterial emission fluxes from manure-fertilized agricultural soil(Oxford : Wiley-Blackwell, 2020) Thiel, Nadine; Münch, Steffen; Behrens, Wiebke; Junker, Vera; Faust, Matthias; Biniasch, Oliver; Kabelitz, Tina; Siller, Paul; Boedeker, Christian; Schumann, Peter; Roesler, Uwe; Amon, Thomas; Schepanski, Kerstin; Funk, Roger; Nübel, UlrichThis is the first study to quantify the dependence on wind velocity of airborne bacterial emission fluxes from soil. It demonstrates that manure bacteria get aerosolized from fertilized soil more easily than soil bacteria, and it applies bacterial genomic sequencing for the first time to trace environmental faecal contamination back to its source in the chicken barn. We report quantitative, airborne emission fluxes of bacteria during and following the fertilization of agricultural soil with manure from broiler chickens. During the fertilization process, the concentration of airborne bacteria culturable on blood agar medium increased more than 600 000-fold, and 1 m3 of air carried 2.9 × 105 viable enterococci, i.e. indicators of faecal contamination which had been undetectable in background air samples. Trajectory modelling suggested that atmospheric residence times and dispersion pathways were dependent on the time of day at which fertilization was performed. Measurements in a wind tunnel indicated that airborne bacterial emission fluxes from freshly fertilized soil under local climatic conditions on average were 100-fold higher than a previous estimate of average emissions from land. Faecal bacteria collected from soil and dust up to seven weeks after fertilization could be traced to their origins in the poultry barn by genomic sequencing. Comparative analyses of 16S rRNA gene sequences from manure, soil and dust showed that manure bacteria got aerosolized preferably, likely due to their attachment to low-density manure particles. Our data show that fertilization with manure may cause substantial increases of bacterial emissions from agricultural land. After mechanical incorporation of manure into soil, however, the associated risk of airborne infection is low.
- ItemThe Role of Streptococcus spp. in Bovine Mastitis(Basel : MDPI, 2021) Kabelitz, Tina; Aubry, Etienne; van Vorst, Kira; Amon, Thomas; Fulde, MarcusThe Streptococcus genus belongs to one of the major pathogen groups inducing bovine mastitis. In the dairy industry, mastitis is the most common and costly disease. It not only negatively impacts economic profit due to milk losses and therapy costs, but it is an important animal health and welfare issue as well. This review describes a classification, reservoirs, and frequencies of the most relevant Streptococcus species inducing bovine mastitis (S. agalactiae, S. dysgalactiae and S. uberis). Host and environmental factors influencing mastitis susceptibility and infection rates will be discussed, because it has been indicated that Streptococcus herd prevalence is much higher than mastitis rates. After infection, we report the sequence of cow immune reactions and differences in virulence factors of the main Streptococcus species. Different mastitis detection techniques together with possible conventional and alternative therapies are described. The standard approach treating streptococcal mastitis is the application of ß-lactam antibiotics. In streptococci, increased antimicrobial resistance rates were identified against enrofloxacin, tetracycline, and erythromycin. At the end, control and prevention measures will be considered, including vaccination, hygiene plan, and further interventions. It is the aim of this review to estimate the contribution and to provide detailed knowledge about the role of the Streptococcus genus in bovine mastitis.
- ItemViertelindividuelle Vakuumapplikation für moderne Melksysteme(Darmstadt : KTBL, 2012) Ströbel, Ulrich; Rose-Meierhöfer, Sandra; Hoffmann, Gundula; Ammon, Christian; Amon, Thomas; Brunsch, ReinerDurch den Einsatz von viertelindividueller Melktechnik können die Bedingungen für Melkpersonal und Kühe erheblich verbessert werden. Die getrennte Schlauchführung für die Milch aus den vier Eutervierteln bietet deutliche Vorteile für die technische Weiterentwicklung dieser Melksysteme. Im Folgenden wird der Prototyp eines viertelindividuellen Melksystems mit Vakuumregelungseinheit vorgestellt, der eine milchflussabhängige, präzise Vakuumanpassung für jedes Euterviertel, verbunden mit einer hohen Rate von Sollwert-Istwert-Abgleichen durch die Regelungseinheit, ermöglicht.
- ItemLuftgeschwindigkeit und Hitzebelastung im Milchviehstall - Auswirkungen auf das Tierwohl(Darmstadt : KTBL, 2012) Fiedler, Merike; Hoffmann, Gundula; Loebsin, Christiane; Berg, Werner; von Bobrutzki, Kristina; Ammon, Christian; Amon, ThomasDas Stallklima hat einen wesentlichen Einfluss auf das Wohlbefinden und die Leistungsfähigkeit von Milchkühen. In der vorliegenden Untersuchung wurden Stallklimamessungen innerhalb und außerhalb eines frei gelüfteten Milchviehstalls, mit dem Fokus auf der Luftgeschwindigkeit im Fress- und Liegebereich, durchgeführt. Die Ergebnisse zeigten, dass die untersuchten Stallbereiche aufgrund der heterogen auftretenden Luftgeschwindigkeiten unterschiedlich belüftet wurden. Des Weiteren wurden die Stallklimamessungen mit physiologischen Tierparametern korreliert, um sie in Bezug auf das thermische Wohlbefinden der Tiere interpretieren zu können. An heißen Tagen wichen die analysierten Parameter deutlich von den übrigen Tagen ab.
- ItemAnwendung der Infrarotthermografie bei ferkelführenden Sauen(Darmstadt : KTBL, 2013) Schmidt, Mariana; Hoffmann, Gundula; Ammon, Christian; Schön, Peter; Manteuffel, Christian; Amon, ThomasIn der Nutztierpraxis gilt die Rektaltemperatur als einer der wichtigsten Indikatoren für die Tiergesundheit. Die rektale Temperaturmessung ist jedoch zeitaufwendig und erfordert direkten Tierkontakt. Die Infrarotthermografie (IR-Thermografie) stellt hingegen eine nichtinvasive, kontaktlose Methode dar, um die Körpertemperatur zu messen. Ein Versuch an Sauen im Abferkelbereich unter Praxisbedingungen hat gezeigt, dass sich die Körperregionen Auge und Ohrrücken zur Erfassung der Körpertemperatur mittels IR-Thermografie gut eignen. Damit kann die IR-Thermografie einen wesentlichen Beitrag zur gezielten Krankheitsprävention und zur Verbesserung des Tierwohls ferkeIführender Sauen leisten.
- ItemWindkanaluntersuchungen an einem frei gelüfteten Milchviehstall(Darmstadt : KTBL, 2013) Fiedler, Merike; Schröter, Knut; Reinhardt, Andreas; Saha, Chayan; Loebsin, Christiane; Berg, Werner; Amon, ThomasDie Luftdurchströmung von frei gelüfteten Ställen und der sich daraus ergebende Luftwechsel bestimmen das Stallklima und die Emissionsraten von Schadstoffen. In der Praxis sind diese Kenngrößen aufgrund der zeitlichen wie räumlichen Variabilität der vorherrschenden Prozesse nur schwer zu erfassen. Laborexperimente im Windkanal können unter kontrollierten Bedingungen statistisch repräsentative Daten erzeugen und damit Praxismessungen sinnvoll ergänzen. Windkanalmessungen der horizontalen Windgeschwindigkeitskomponenten wurden an einem Modell eines frei gelüfteten Milchviehstalles durchgeführt. Die Messungen erfolgten unter einer turbulenzarmen Anströmung, um den Einfluss der Einbauten im Stallmodell auf die Luftströmung erfassen zu können. Die Ergebnisse zeigen, dass die Einbauten und der Futtertisch die gemessenen Strömungsgrößen beeinflussen.
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