Examinations of the effect of various anionic supplements on the renal excretion of macro elements and their diagnostic value with regard to the prevention of hypocalcaemic parturient paresis in dairy cows

Deckblatt-Impressum Inhaltsverzeichnis Verzeichnis der verwendeten Abkürzungen Einleitung Literaturübersicht Material und Methoden Ergebnisse Diskussion Schlussfolgerungen Zusammenfassung Summary Literaturverzeichnis Anhang Danksagung SelbständigkeitserklärungTrotz jahrelanger intensiver Ursachenforschung und Suche nach Möglichkeiten der Prophylaxe gehört die hypocalcaemische Gebärparese noch immer zu den häufigsten metabolischen Störungen bei Hochleistungskühen. Die hohe Inzidenz, die damit in Verbindung zu bringenden Folgeerkrankungen sowie Beeinträchtigungen der Fruchtbarkeit und effektiven Nutzungsdauer der Tiere sind Ausdruck für die wirtschaftliche Bedeutung dieser Krankheit. Neben anderen prophylaktischen Maßnahmen hat das DCAB-Konzept (dietary-cation-anion- balance) und der damit verbundene Einsatz von sauren Salzen auch vermehrtes Interesse auf dem Gebiet der Wiederkäuerfütterung hervorgerufen. Dieses Verfahren wird zunehmend eingesetzt, die Erfahrungen sind jedoch sehr widersprüchlich. Ziel dieser Arbeit sollte sein, die Auswirkungen verschiedener Anionenergänzungen in Form von Einzelsalzen (CaCl2·2H2O; CaSO4·2H2O; CaSO4·2H2O-D10 (Körnungsgrad: 10 µm); MgCl2·6H2O; MgSO4·7H2O; NaCl; NH4Cl; (NH4)2SO4) und Salzmischungen (CaCl2·2H2O +MgSO4·7H2O; NH4Cl+CaSO4·2H2O) auf die renale Elektrolytausscheidung bei Milchkühen vergleichend darzustellen und die diagnostische Aussagekraft dieser Parameter hinsichtlich eines Einsatzes saurer Salze zu prüfen. Dazu wurden an N = 11 pansenfistulierten Rindern der Rasse Deutsche-Schwarz-Bunte x Holstein Friesian experimentelle Untersuchungen durchgeführt. Alle Tiere waren weiblich, nicht tragend, nicht laktierend und hatten mindestens zwei Laktationsstadien durchlaufen. Die zu testenden Salze wurden pro Versuchsperiode über einen Zeitraum von 2 Wochen mit einer Tagesdosis von 2 Equivalenten je Tier randomisiert gemäß einem 11x11 lateinischen Quadrat zeitgleich zur Futteraufnahme intraruminal verabreicht. Von allen einbezogenen Mengenelementen im Harn ist Kalzium am besten geeignet, die Wirkung der sauren Salze und deren Einfluss auf den Säuren-Basen-Haushalt (SBH) sowie den Kalziumstoffwechsel wiederzugeben. Die engen Beziehungen zu Parametern des SBH und zur DCAB führen zu der Forderung, die renale Kalziumkonzentration zusammen mit der Netto-Säuren-Basen-Ausscheidung (NSBA) und der DCAB als Kontrollparameter der ersten Wahl einzustufen. Als Zielgröße einer optimalen Wirkung von Anionenrationen sind Kalziumkonzentrationen im Bereich von 8 bis 15 mmol/l Harn bzw. FECa von 2,5 bis 3,5% anzustreben. Die Kalium- und Phosphatkonzentrationen im Harn bleiben unter der Salzbehandlung relativ unbeeinflusst. Ein hyperphosphaturischer Effekt infolge azidotischer Belastungen wird nicht nachgewiesen. Natrium-, Magnesium- und Chloridverbindungen führen aufnahmebedingt zu einer signifikant erhöhten Ausscheidung dieser Elemente. Die Bestimmung der renalen fraktionierten Exkretion von Mengenelementen zeigt in dieser Studie keine deutlichen Vorteile im Vergleich zur renalen Mengenelementkonzentration. Das Tagesharnvolumen wird unter Einsatz von sauren Salzen geringfügig erhöht, verbleibt aber innerhalb physiologischer Bereiche. Ein zirkadianer Rhythmus kann für die Chlorid-, nicht aber für die Kalziumausscheidung nachgewiesen werden. Zugrunde liegende Einflüsse bedürfen weiterer Untersuchungen. Gemessen an den Parametern NSBA, Harn-pH und renale Kalziumkonzentration bewirken die Salze CaCl2, CaSO4-D10 und NH4Cl anhand der vorliegenden Ergebnisse die stärksten Auslenkungen. Unter Einbeziehung der Bewertungskriterien Wirksamkeit und Schmackhaftigkeit stellt sich CaSO4-D10 als saures Salz der ersten Wahl heraus.Despite years of intensive research on causes and in search of preventive methods, hypocalcaemic parturient paresis is still one of the most common metabolic disorders of highyielding dairy cows. The high incidence, follow-up diseases in connection with these disorders as well as the reduction of fertility and effective productivity have been signs for the economic significance of milk fever. Compared with other preventive measures the dietarycation-anion-balance (DCAB) and the use of anionic salts in connection with it have caused an intensified interest in dry cow feeding management. This method has gained increasing practical influence but experiences have been contradictory up till now. The objective of this study was to compare the effects of various anionic supplements in form of single salts (CaCl2·2H2O; CaSO4·2H2O; CaSO4·2H2O-D10 (degree of granulate: 10 µm); MgCl2·6H2O; MgSO4·7H2O; NaCl; NH4Cl; (NH4)2SO4) and mixed salts (CaCl2·2H2O +MgSO4·7H2O; NH4Cl+CaSO4·2H2O) on the urinary excretion of macro elements and to evaluate the diagnostic value of these elements with regard to the use of anionic salts in dairy cows. Therefore experimental examinations were carried out with N = 11 cows belonging to the breed German black pied cows x Holstein Friesian, each with a ruminal fistula. All animals were female, not pregnant, not lactating and had past at least two previous lactations. The tested salts were given in a daily dose of 2 equivalents per animal over a time span of 2 weeks per test period. The sequences were randomized according to an 11 x 11 Latin square design. The salts were administered directly into the rumen during feeding time. Among all included macro elements in the urine, calcium is best to show the effects of anionic salts and their influence on acid-base-balance (ABB) as well as on calcium metabolism. The close relations to parameters of ABB and to DCAB claim the classification of the urinary concentration of calcium in connection with net-acid-base-excretion (NABE) and DCAB as top monitoring parameter. A concentration of calcium in urine from 8 to 15 mmol/l as well as a renal fractional excretion of calcium from 2.5 to 3.5% can be seen as dimensions with optimal effects when using anionic rations. The concentrations of potassium and phosphate in the urine were relatively stable during the treatment with salts. Hyperphosphaturia as a result of acidogenic conditions does not occur.Compounds formed out of sodium, magnesium and chloride lead to a significantly increased urinary excretion of these elements depending on the ingestion. In this study the determination of the renal fractional excretion of macro elements does not offer any clear advantages compared to the determination of the urinary concentration of macro elements. The 24-hour quantity of urine was slightly increased during the use of anionic salts but remains within physiological limits. A certain rhythm depending on the time of a day can be proved for the renal excretion of chloride but not for the renal excretion of calcium. Further studies of underlying influences seem to be necessary here. Referring to the results at hand the salts CaCl2, CaSO4-D10 and NH4Cl show the strongest reactions to the parameters NABE, urinary-pH and renal concentration of calcium. Including criteria like effectiveness and palatability CaSO4-D10 presents itself as top anionic salt

It Pays to Prepare: Human Motor Preparation Depends on the Relative Value of Potential Response Options

Alternative motor responses can be prepared in parallel. Here, we used electroencephalography (EEG) to test whether the parallel preparation of alternative response options is modulated by their relative value. Participants performed a choice response task with three potential actions: isometric contraction of the left, the right, or both wrists. An imperative stimulus (IS) appeared after a warning cue, such that the initiation time of a required action was predictable, but the specific action was not. To encourage advanced preparation, the target was presented 200 ms prior to the IS, and only correct responses initiated within ±100 ms of the IS were rewarded. At baseline, all targets were equally rewarded and probable. Then, responses with one hand were made more valuable, either by increasing the probability that the left or right target would be required (Exp. 1; n = 31) or by increasing the reward magnitude of one target (Exp. 2, n = 36). We measured reaction times, movement vigor, and an EEG correlate of action preparation (value-based lateralized readiness potential) prior to target presentation. Participants responded earlier to more frequent and more highly rewarded targets, and movements to highly rewarded targets were more vigorous. The EEG was more negative over the hemisphere contralateral to the more repeated/rewarded hand, implying an increased neural preparation of more valuable actions. Thus, changing the value of alternative response options can lead to greater preparation of actions associated with more valuable outcomes. This preparation asymmetry likely contributes to behavioral biases that are typically observed toward repeated or rewarded targets

Learning to throw

Feedback, Trainingsplan und individuelle Unterschiede zwischen Lernern sind drei Faktoren die den motorischen Fertigkeitserwerb beeinflussen und wurden in der vorliegenden Dissertation untersucht. Ein besonderer Fokus lag auf den zugrundeliegenden Gehirnprozessen von Feedbackverarbeitung und Handlungsvorbereitung, die mittels ereigniskorrelierter Potenziale (EKPs) untersucht wurden. 120 Teilnehmer trainierten auf virtuelle Zielscheiben zu werfen und wurden in einer Folgesitzung auf Abruf und Transfer getestet. Der Trainingsplan verursachte entweder hohe contextual interference (CI) (randomisiert) oder niedrige CI (geblockt). In einer anschließenden Onlinestudie, bearbeiteten 80% der Teilnehmer eine Untermenge der Raven advanced progressive matrices, die schlussfolgerndes Denken (SD) erfassen. Unter hoher CI hängt besseres SD mit größerem Zuwachs im Training und höherer Performanz in Abruf und Transfer zusammen. Ähnliche Effekte von SD im späten Trainingsverlauf unter niedriger CI lassen darauf schließen, dass Variabilität eine notwendige Voraussetzung für positive Effekte von SD ist. Wir folgern, dass CI das Ausmaß an Praxisvariabilität über den Trainingsverlauf beeinflusst und darüber moduliert, ob Regeln abstrahiert werden (Studie 1). Diese Interpretation wird durch differenzielle Lerneffekte auf EKPs in der Vorbereitungsphase gestützt. Hohe CI führt zu einer stärkeren Abnahme von aufmerksamkeits- und kontrollbezogenen EKPs während der Vorbereitungsphase. Die CNV Amplitude, als Maß motorischer Vorbereitungsaktivität nimmt zu, wenn die Anforderungen in Training und Abruf gleich sind, wie bei niedriger CI. Das spricht für zwei parallele Mechanismen motorischen Lernens, die gemeinsam zur CNV Amplitude beitragen (Studie 2). Wir zeigten außerdem, dass sich graduelle Verarbeitung positiven Performanz-Feedbacks in der Variation der Amplitude der Reward Positivity widerspiegelt (Studie 3).Feedback, training schedule and individual differences between learners influence the acquisition of motor skills and were investigated in the present thesis. A special focus was on brain processes underlying feedback processing and motor preparation, investigated using event related potentials (ERPs). 120 participants trained to throw at virtual targets and were tested for retention and transfer. Training schedule was manipulated with half of the participants practicing under high contextual interference (CI) (randomized training) and the other half under low CI (blocked training). In a follow-up online study, 80% of the participants completed a subset of the Raven advanced progressive matrices, testing reasoning ability. Under high CI, participants’ reasoning ability was related to higher performance increase during training and higher subsequent performance in retention and transfer. Similar effects in late stages of low CI training indicate, that variability is a necessary prerequisite for beneficial effects of reasoning ability. We conclude, that CI affects the amount of variability of practice across the course of training and the abstraction of rules (Study 1). Differential learning effects on ERPs in the preparatory phase foster this interpretation. High CI shows a larger decline in attention- and control-related ERPs than low CI. CNV amplitude, as a measure of motor preparatory activity, increases with learning only, when attention demands of training and retention are similar, as in low CI training. This points to two parallel mechanisms in motor learning, with a cognitive and a motor processor, mutually contributing to CNV amplitude (Study 2). In the framework of the “reinforcement learning theory of the error related negativity”, we showed, that positive performance feedback is processed gradually and that this processing is reflected in varying amplitudes of reward positivity (Study 3). Together these results provide new insights on motor learning

Group-Level EEG-Processing Pipeline for Flexible Single Trial-Based Analyses Including Linear Mixed Models

Here we present an application of an EEG processing pipeline customizing EEGLAB and FieldTrip functions, specifically optimized to flexibly analyze EEG data based on single trial information. The key component of our approach is to create a comprehensive 3-D EEG data structure including all trials and all participants maintaining the original order of recording. This allows straightforward access to subsets of the data based on any information available in a behavioral data structure matched with the EEG data (experimental conditions, but also performance indicators, such accuracy or RTs of single trials). In the present study we exploit this structure to compute linear mixed models (LMMs, using lmer in R) including random intercepts and slopes for items. This information can easily be read out from the matched behavioral data, whereas it might not be accessible in traditional ERP approaches without substantial effort. We further provide easily adaptable scripts for performing cluster-based permutation tests (as implemented in FieldTrip), as a more robust alternative to traditional omnibus ANOVAs. Our approach is particularly advantageous for data with parametric within-subject covariates (e.g., performance) and/or multiple complex stimuli (such as words, faces or objects) that vary in features affecting cognitive processes and ERPs (such as word frequency, salience or familiarity), which are sometimes hard to control experimentally or might themselves constitute variables of interest. The present dataset was recorded from 40 participants who performed a visual search task on previously unfamiliar objects, presented either visually intact or blurred. MATLAB as well as R scripts are provided that can be adapted to different datasets

Group-Level EEG-Processing Pipeline for Flexible Single Trial-Based Analyses Including Linear Mixed Models

Here we present an application of an EEG processing pipeline customizing EEGLAB and FieldTrip functions, specifically optimized to flexibly analyze EEG data based on single trial information. The key component of our approach is to create a comprehensive 3-D EEG data structure including all trials and all participants maintaining the original order of recording. This allows straightforward access to subsets of the data based on any information available in a behavioral data structure matched with the EEG data (experimental conditions, but also performance indicators, such accuracy or RTs of single trials). In the present study we exploit this structure to compute linear mixed models (LMMs, using lmer in R) including random intercepts and slopes for items. This information can easily be read out fromthematched behavioral data, whereas itmight not be accessible in traditional ERP approaches without substantial effort.We further provide easily adaptable scripts for performing cluster-based permutation tests (as implemented in FieldTrip), as a more robust alternative to traditional omnibus ANOVAs. Our approach is particularly advantageous for data with parametric within-subject covariates (e.g., performance) and/or multiple complex stimuli (such as words, faces or objects) that vary in features affecting cognitive processes and ERPs (such as word frequency, salience or familiarity), which are sometimes hard to control experimentally or might themselves constitute variables of interest. The present dataset was recorded from 40 participants who performed a visual search task on previously unfamiliar objects, presented either visually intact or blurred. MATLAB as well as R scripts are provided that can be adapted to different datasets.Peer Reviewe