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Methane emissions from the storage of liquid dairy manure: Influences of season, temperature and storage duration
Methane emissions from livestock manure are primary contributors to GHG emissions from agriculture and options for their mitigation must be found. This paper presents the results of a study on methane emissions from stored liquid dairy cow manure during summer and winter storage periods. Manure from the summer and winter season was stored under controlled conditions in barrels at ambient temperature to simulate manure storage conditions. Methane emissions from the manure samples from the winter season were measured in two time periods: 0 to 69 and 0 to 139 days. For the summer storage period, the experiments covered four time periods: from 0 to 70, 0 to 138, 0 to 209, and 0 to 279 continuous days, with probing every 10 weeks. Additionally, at the end of all storage experiments, samples were placed into eudiometer batch digesters, and their methane emissions were measured at 20 °C for another 60 days to investigate the potential effect of the aging of the liquid manure on its methane emissions. The experiment showed that the methane emissions from manure stored in summer were considerably higher than those from manure stored in winter. CH4 production started after approximately one month, reaching values of 0.061 kg CH4 kg−1 Volatile Solid (VS) and achieving high total emissions of 0.148 kg CH4 kg−1 VS (40 weeks). In winter, the highest emissions level was 0.0011 kg CH4 kg−1 VS (20 weeks). The outcomes of these experimental measurements can be used to suggest strategies for mitigating methane emissions from manure storage.
Viertelindividuelle Vakuumapplikation für moderne Melksysteme
Durch 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.
Luftgeschwindigkeit und Hitzebelastung im Milchviehstall - Auswirkungen auf das Tierwohl
Das 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.
Direct Measurements of the Volume Flow Rate and Emissions in a Large Naturally Ventilated Building
The direct measurement of emissions from naturally ventilated dairy barns is challenging due to their large openings and the turbulent and unsteady airflow at the inlets and outlets. The aim of this study was to quantify the impacts of the number and positions of sensors on the estimation of volume flow rate and emissions. High resolution measurements of a naturally ventilated scaled building model in an atmospheric boundary layer wind tunnel were done. Tracer gas was released inside the model and measured at the outlet area, using a fast flame ionization detector (FFID). Additionally, the normal velocity on the area was measured using laser Doppler anemometry (LDA). In total, for a matrix of 65 × 4 sensor positions, the mean normal velocities and the mean concentrations were measured and used to calculate the volume flow rate and the emissions. This dataset was used as a reference to assess the accuracy while systematically reducing the number of sensors and varying the positions of them. The results showed systematic errors in the emission estimation up to +97%, when measurements of concentration and velocity were done at one constant height. This error could be lowered under 5%, when the concentrations were measured as a vertical composite sample.
Windkanaluntersuchungen an einem frei gelüfteten Milchviehstall
Die 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.
How the Selection of Training Data and Modeling Approach Affects the Estimation of Ammonia Emissions from a Naturally Ventilated Dairy Barn—Classical Statistics versus Machine Learning
Environmental protection efforts can only be effective in the long term with a reliable quantification of pollutant gas emissions as a first step to mitigation. Measurement and analysis strategies must permit the accurate extrapolation of emission values. We systematically analyzed the added value of applying modern machine learning methods in the process of monitoring emissions from naturally ventilated livestock buildings to the atmosphere. We considered almost 40 weeks of hourly emission values from a naturally ventilated dairy cattle barn in Northern Germany. We compared model predictions using 27 different scenarios of temporal sampling, multiple measures of model accuracy, and eight different regression approaches. The error of the predicted emission values with the tested measurement protocols was, on average, well below 20%. The sensitivity of the prediction to the selected training dataset was worse for the ordinary multilinear regression. Gradient boosting and random forests provided the most accurate and robust emission value predictions, accompanied by the second-smallest model errors. Most of the highly ranked scenarios involved six measurement periods, while the scenario with the best overall performance was: One measurement period in summer and three in the transition periods, each lasting for 14 days.
Airborne bacterial emission fluxes from manure-fertilized agricultural soil
This 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.
Anwendung der Infrarotthermografie bei ferkelführenden Sauen
In 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.
Particulate matter emissions during field application of poultry manure - The influence of moisture content and treatment
Along with industry and transportation, agriculture is one of the main sources of primary particulate matter (PM) emissions worldwide. Bioaerosol formation and PM release during livestock manure field application and the associated threats to environmental and human health are rarely investigated. In the temperate climate zone, field fertilization with manure seasonally contributes to local PM air pollution regularly twice per year (spring and autumn). Measurements in a wind tunnel, in the field and computational fluid dynamics (CFD) simulations were performed to analyze PM aerosolization during poultry manure application and the influence of manure moisture content and treatment. A positive correlation between manure dry matter content (DM) and PM release was observed. Therefore, treatments strongly increasing the DM of poultry manure should be avoided. However, high manure DM led to reduced microbial abundance and, therefore, to a lower risk of environmental pathogen dispersion. Considering the findings of PM and microbial measurements, the optimal poultry manure DM range for field fertilization was identified as 50–70%. Maximum PM10 concentrations of approx. 10 mg per m3 of air were measured during the spreading of dried manure (DM 80%), a concentration that is classified as strongly harmful. The modeling of PM aerosolization processes indicated a low health risk beyond a distance of 400 m from the manure application source. The detailed knowledge about PM aerosolization during manure field application was improved with this study, enabling manure management optimization for lower PM aerosolization and pathogenic release into the environment.
The Role of Streptococcus spp. in Bovine Mastitis
The 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.