Open Access

Targeted mastitis treatment concepts are the most scientifically validated approaches to comply with the prudent use of antimicrobials. However, this approach is still a challenge for many farmers, who often lack experience with it. Another option for more prudent use of antibiotics in mastitis therapy could be the initial treatment with a nonsteroidal anti-inflammatory drug (NSAID) for nonsevere mastitis. A randomized, multiherd, noninferiority study was carried out to compare 2 treatments of nonsevere mastitis cases. The animals in the studied group were treated with systemic NSAID (ketoprofen [KE]; KE group; n = 104), followed by antibiotic (AB) treatment only in cases without clinical improvement, and the animals in the reference group (AB group) received an intramammary AB (n = 118). The study included 222 cases of nonsevere clinical mastitis on 3 conventional dairy farms in northern Germany between November 2022 and November 2023. Study outcomes were clinical cure at d 5, bacteriological cure, clinical mastitis recurrence in a period of 60 d, and new infection risk. Mixed logistic regression was used to analyze the effect of treatment on outcomes. The noninferiority assumption was checked with the CI of the treatment difference for clinical cure at d 5, calculating using the LSM and their SD. With regard to the clinical cure on d 5, the treatment in the KE group was inferior. Clinical cure (84.7% [100/118] and 61.5% [64/104]) and bacteriological cure (79.3% [73/92] and 61.2% [41/67]) were significantly higher in the AB group than in the KE group. The risks for recurrent cases (7.3% [8/109] and 15.7% [14/89]) were significantly lower in the AB group than in the KE group. The new infection risk did not differ significantly between the treatment groups (6.8% [8/118] in the AB group and 6.7% [7/104] in the KE group). In 87% of the cases (n = 90) of the KE group, a subsequent antibiotic treatment was not necessary to reach clinical cure on d 5. The use of KE as the sole initial treatment for nonsevere mastitis led to a reduction of antibiotic doses by 86%. Our findings revealed that systemic treatment with KE resulted in lower clinical and bacteriological cure rates, higher recurrence rates of clinical mastitis, and an elevated risk of new infections compared with the antibiotic-treated group. Nevertheless, in more than 85% of cases treated with KE, additional intramammary antibiotic treatment was unnecessary. Thus, this treatment concept represents an alternative in mastitis treatment that promoted the deliberate and selective use of antibiotics but has limitations in terms of treatment efficacy in mastitis. A targeted mastitis concept based on the identification of the bacterium involved could help to select cases to be treated with KE alone and therefore overcome this limitation.

Adopting a new milking system at a dairy farm causes various changes. This study examined the impact on udder health when changing from a conventional milking system to an automatic milking system. For this purpose, quarter milk samples were taken six times from 138 cows at one conventional dairy farm in Northern Germany over a five-week period around the time of the milking system changeover. To assess udder health, the absolute number of new intramammary infections and the causative pathogen genera and species were analysed for each individual study time point. Pathogen species were detected using matrix-assisted laser desorption ionisation time-of-flight, and the infection dynamics were analysed using two Poisson regression models. In addition, the prevalence and incidence of new intramammary infections and the infection dynamics of the four most frequently isolated pathogen species were calculated. Mixed models were used to determine the development of the new infection rate, the somatic cell count, the teat-end condition, and the udder hygiene between the individual study time points and to compare the new infection rate before and after the changeover of the milking system. After the automatic milking system had been installed, a significant increase in the quarter-level somatic cell count occurred (p < 0.001). Two days before the installation of the automatic milking system, the mean quarter-level somatic cell count was 11,940 cells/mL milk; one sampling date later, 8 days after the changeover, a mean quarter-level somatic cell count of 60,117 cells/mL milk was measured. The significant increase in somatic cell count was probably caused by the time between the last milking and the quarter milk sampling. Additionally, significantly more udders were scored as clean 8 days (95%) and 15 days (96%) after the changeover of the milking system compared to at the last sampling date (88%). Also, significantly more teat ends were classified as free of hyperkeratosis 15 days (80%) compared to 22 days (67%) after the changeover of the milking system. The highest number of absolute new intramammary infections was detected 8 days before the transition of the milking system (28.6%). The lowest number of absolute new intramammary infections occurred 8 days after the change to the automatic milking system (11.0%). Minor mastitis pathogens, such as non-aureus staphylococci and coryneform bacteria, were mainly responsible for the development of new intramammary infections. The most frequently isolated pathogen species were Staphylococcus sciuri, Staphylococcus chromogenes, Staphylococcus haemolyticus, and Corynebacterium amycolatum, with a prevalence of up to 23.9, 10.7, 8.4, and 5.3%, respectively. By comparing the new infection rate before and after the changeover of the milking system, it was possible to establish that the changeover to the automatic milking system had no significant influence on the new intramammary infection rate (p = 0.988). Therefore, this trial confirmed that the changeover from a conventional milking system to an automatic milking system had no negative influence on udder health.

Cross-sectional 2D models often represent a computationally efficient alternative to full 3D models, when simulating complex multi-physical magnet systems. However, especially for the case of self-protected, superconducting magnets, where the stored energy has to be dissipated within the magnet coils, the thermal diffusion and the quench development in all three dimensions become key aspects. In order to further improve the simulation of transients in 2D models, a new modelling method for simplified quench development along the direction of the transport current is introduced. The original 2D model is hereby utilized for modelling the thermal domain, and the electrical resistance of each turn is scaled by the estimated time-dependent fraction of quenched conductor. Furthermore, the turn to turn quench propagation following the electrical connections is implemented. The proposed approach allows a very computationally efficient and easy-to-implement calculation since the model is effectively two-dimensional while providing a good approximation of the coil resistance development with sufficient accuracy. In order to illustrate the proposed quench-propagation modelling approach, simulations are compared to experimental results for the case of a self-protected, superconducting Nb-Ti dipole magnet. In general, a very good agreement between measurements and simulations was achieved.

Bürstenlose Generatorsysteme mit doppelt gespeisten Kaskadenmaschinen werden zurzeit für die regenerative Energieerzeugung z. B. mit Windkraftanlagen untersucht. Sie sind eine Alternative zu Generatorsystemen mit doppelt gespeisten Induktionsmaschinen. Kaskadenmaschinen arbeiten mit zwei Drehfeldern verschiedener Polpaarzahlen. Im Stator befinden sich zwei Wicklungen für die beiden Polpaarzahlen oder eine Wicklung zur gleichzeitigen Erzeugung der beiden Drehfelder über jeweils getrennte Anschlüsse. Der Rotor trägt eine in sich kurzgeschlossene Wicklung, die gleichzeitig mit beiden Drehfeldern verkettet ist und deren Strom beide Drehfelder gleichzeitig erzeugt. Der vorliegende Beitrag beschreibt wie die elektromagnetische Wirkung unsymmetrischer Rotorwicklungen für Kaskadenmaschinen mit der Drehfeldanalyse behandelt werden kann. Dieser Beitrag ist eine Erweiterung des früheren Beitrags Kaskadenmaschine ... Analyse der Rotorwicklung (https://doi.org/10.25968/opus-3071) um die Kenngrößen der Rotorwicklung. Die Rotorwicklungen erzeugen gleichzeitigen beide Grundfelder der Kaskadenmaschine. Sie sind z. T. mit Wicklungszweigen aufgebaut, die in verschiedenen Knoten zusammen geschaltet sind. Mit dem hier dargestellten Rechenverfahren wird die elektromagnetische Kopplung zwischen den Wicklungszweigen und zur Statorwicklung erfasst. Für das Verhalten der Wicklung werden Kenngrößen angegeben.

Bovine mastitis is one of the most important diseases in the dairy industry and has detrimental impact on the economy and welfare of the animals. Further, treatment failure results in increased antibiotic use in the dairy industry, as some of these mastitis cases for unknown reasons are not resolved despite standard antibiotic treatment. Chronic biofilm infections are notoriously known to be difficult to eradicate with antibiotics and biofilm formation could be a possible explanation for mastitis cases that are not resolved by standard treatment. This paper reviews the current literature on biofilm in bovine mastitis research to evaluate the status and methods used in the literature. Focus of the current research has been on isolates from milk samples and investigation of their biofilm forming properties in vitro. However, in vitro observations of biofilm formation are not easily comparable with the in vivo situation inside the udder. Only two papers investigate the location and distribution of bacterial biofilms inside udders of dairy cows with mastitis. Based on the current knowledge, the role of biofilm in bovine mastitis is still unclear and more in vivo investigations are needed to uncover the actual role of biofilm formation in the pathogenesis of bovine mastitis.