Gesundheit und Leistungsfähigkeit von Milchkühen im ökologischen Landbau interdisziplinär betrachtet – eine (Interventions-) Studie zu Stoffwechselstörungen und Eutererkrankungen unter Berücksichtigung von Grundfuttererzeugung, Fütterungsmanagement und Tierhaltung

Im Mittelpunkt des Projektes stand die Stoffwechsel- und Eutergesundheit von ökologisch gehaltenen Milchkühen im prä- und peripartalen Zeitraum sowie in den ersten 100 Laktationstagen und deren Beeinflussung durch die Futter- und Nährstoffversorgung und die Haltungsumwelt im umfassenden Sinn. In einer bundesweiten Feldstudie auf 106 ökologisch wirtschaftenden Milchviehbetrieben erfolgten Erhebungen mit dem Ziel einer Risikomodellierung zu Stoffwechsel- und Eutererkrankungen. Vor diesem Hintergrund wurden die Produktionssysteme von der Pflanzenzusammensetzung im Grünland und im Ackerfutter über die Grobfutterproduktion, Futterqualität und Rationsgestaltung, Haltungsumwelt bis hin zur Tiergesundheit und Milchqualität analysiert, um hier einzelbetriebliche Risikoeinschätzungen vorzunehmen, Optimierungspotenziale aufzuzeigen und Handlungsempfehlungen abzuleiten, die anschließend betriebsindividuell implementiert wurden. Die Effektivität des so geschaffenen präventiv orientierten Tiergesundheitsmanagements wurde anhand der Entwicklung ausgewählter Kennzahlen der Euter- und Stoffwechselgesundheit geprüft. Es konnte gezeigt werden, dass sich mit dieser Vorgehensweise auch unter Praxisbedingungen die Tiergesundheitssituation signifikant verbes-sern lässt. Die Feldstudie wurde mit experimentellen Untersuchungen ergänzt, die sich speziellen Fragen der Analyse von nXP in Grasprodukten, des Kraftfuttereinsatzes, der Wahl der geeigneten Rasse, dem Infektionsgeschehen, der Nutzung von Haltungstechniken im Fütterungsmanagement und der Verbesserung der Grasnarbe widmeten. Die im Projekt generierten, aufgrund ihrer Ableitung aus der Praxis widerspruchsarmen Erkenntnisse wurden über vielfältige Formen des Wissenstransfers an die Akteure in der Ökologischen Milchviehhaltung vermittelt. Ein Merkblatt zur Euter- und Stoffwechselgesundheit bei Biomilchkühen und ein modular aufgebautes Wissenstransferkonzept wurden erarbeitet, um die Projektergebnisse nachhaltig nutzen zu können

Efficiency of two commercial onfarm pasteurizers for inactivation of mastitis pathogens in milk intended for feeding od calves

Two commercially available pasteurizers for on farm pasteurization of milk intended for feeding calves were tested for their efficiency to inactivate mastitis pathogens. Raw bulk tank milk of the experimental farm Schaedtbek of the Max Rubner-Institute was artificially contaminated with twelve different strains of mastitis pathogens (intended level 7-8 log10 colony forming units [cfu]/ml). The average contamination level was 7.6 log10 cfu/ml in trials with pasteurizer 1 (P1) and 7.3 log10 cfu/ml in trials with pasteurizer 2 (P2), with lowest counts for yeasts (5.1 log10 cfu/ml for P1 and P2). Average reduction rates of > 5.8 log10 cfu/ml for P1 (72 degrees C, 12 s) and > 6.2 log10 cfu/ml for P2 (64 degrees C, 35 min) revealed an appropriate efficiency of both pasteurizers for practical purposes. Pathogens surviving pasteurization (enterococci in trials with both pasteurizers and of Staphylococcus aureus and Escherichia coli with P1) demonstrate the limits of pasteurization as a function of raw milk quality and emphasize the necessity for appropriate handling of pasteurized milk to prevent excessive multiplication of microbial pathogens

Feeding untreated and pasteurized waste milk and bulk milk to calves: effects on calf performance, health status and antibiotic resistance of faecal bacteria

Non-saleable milk (waste milk, WM) is contaminated with an undefined spectrum of potentially harmful pathogens and antimicrobial residues. The objective of this study was to determine the impact of feeding bulk milk (BM) or WM - both pasteurized or not - on calf performance, health and the antibiotic resistance of specific faecal bacteria. A total of 114 calves from a large-scale dairy were housed outdoors in individual hutches and were randomly assigned to one of four feeding groups. The calves were fed either WM, pasteurized WM (pWM), BM or pasteurized BM (pBM) from day 3 to 56 of life. Milk samples taken from the pasteurizer and calves' nipple buckets were investigated at regular intervals for total plate count and counts of thermoduric bacteria, coliforms and mastitis pathogens. Faecal samples were taken on days 2, 14, 28 and 56 of life from randomly selected calves of the WM, pWM and BM groups (each N = 8-9) and processed to obtain from each sample preferably two isolates of Escherichia (E.) coli and Enterococcus spp. respectively. Isolates were tested for their antimicrobial susceptibility to 25 antimicrobial agents by broth microdilution. Daily weight gain, milk and calf starter intake and health parameters did not differ significantly between the calves of the four feeding groups. The proportion of resistant E. coli isolates was significantly higher in calves fed WM and in calves fed pWM (most pronounced for cephalosporins) than in calves receiving BM. No differences in resistance were found for Enterococus spp. Thus, the concerns for selecting resistant faecal bacteria by feeding WM seem to be justified. Nonetheless, pasteurized WM of cows not treated with antimicrobials represents an acceptable feed for young calves

Large Eddy Simulation of a laboratory-scale gas-assisted pulverized coal combustion chamber under oxy-fuel atmospheres using tabulated chemistry

This paper analyses a new gas-assisted pulverized coal combustion chamber, specially designed for the validation of numerical models under oxy-fuel atmospheres. For this purpose, an overall method is developed based on Large Eddy Simulation (LES) for oxy-fuel pulverized coal combustion chambers. One essential aspect of this is the embedding of a 4D Flamelet Generated Manifold (FGM) table coupled with an artificially thickened flame (ATF) model in the Euler-Lagrange (EL) framework. The four dimensions of the generated manifold represent the finite rate chemistry, mixing of volatiles, and char products and heat losses in the gas phase. Before the model is applied in the combustion chamber, its validity is demonstrated utilizing verification cases. Subsequently, the simulation results of the combustion chamber are validated and discussed with the help of the available measurement data. Operating points with increasing complexity are investigated, starting with a single-phase case that analyzes the reproduction of the assisting methane flame based on tabulated chemistry coupled with ATF. For the validation process, velocity fields from Particle Image Velocimetry (PIV) are used as well as flame positions from planar laser-induced fluorescence of the OH radical (OH-PLIF). Subsequently, operating conditions using different coal mass flows are investigated. To validate the flame stabilization mechanism, velocity data for the near burner region are available. Further examinations of the gas-assisted coal flame are carried out, in particular the influence of the coal particles on the flame stabilization mechanism is carried out

Untersuchungen zur Untertagevergasung in grosser Teufe Abschlussbericht

With 117 figs., 25 tabs., 112 refs.SIGLETIB: FR 4029 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman