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Multisite study to evaluate a prepartum cholecalciferol injection for prevention of hypocalcemia in pluriparous dairy cows
No full textHypocalcämie ist eine häufig auftretende Stoffwechselstörung der Milchkuh im Zeitraum bis 48 Stunden nach der Abkalbung. Die subklinische Hypocalcämie wird in diesem Zusammenhang häufig als „gateway disease“ bezeichnet, da sie zu zahlreichen Folgeerkrankungen prädisponiert und so zu erheblichen wirtschaftlichen Einbußen und einer Beeinträchtigung der Tiergesundheit führt. Seit den 1970er-Jahren wird bei mehrkalbigen Milchkühen ca. fünf bis sieben Tage vor der erwarteten Kalbung Cholecalciferol gespritzt. Ziel ist es, die Mechanismen der Calciumhomöostase bereits vor der Kalbung zu aktivieren und die Tiere so besser auf das bei Einsetzen der Milchproduktion entstehende Calciumdefizit vorzubereiten (Gürtler et al. 1977).
In der vorliegenden Studie wurde der Einfluss einer Cholecalciferol-Injektion a.p. auf die Serumdynamik von Calcium, Phosphor und Magnesium nach der Kalbung sowie auf die Milchleistung und verschiedene Reproduktionsparameter in der Folgelaktation untersucht. Dazu wurden 446 pluripare Milchkühe, die in der Trockenstehphase eine Ration mit positiver DCAB erhielten, von 11 Betrieben in Nordwest-Deutschland sieben Tage vor dem Kalbedatum mit einer intramuskulären Injektion von 10 Mio. I.E. Cholecalciferol oder einem Placebo behandelt. Alle Tiere wurden fünf bis zehn Tage nach der Kalbung auf Anzeichen einer Metritis untersucht und der Kalbeverlauf sowie das Auftreten von Zwillingen, Totgeburten, klinischer Hypocalcämie und Retentio secundinarum dokumentiert. Bei einer Teilstrichprobe von 95 Tieren wurden an Tag 1, 2 und 3 p.p. jeweils eine Blutprobe entnommen und auf die Konzentration von Calcium, Phosphor und Magnesium untersucht. Des Weiteren wurde bei 38 Tieren zusätzlich zwei Tage nach der Injektion eine weitere Blutprobe entnommen und der Gehalt an Progesteron und Östradiol bestimmt. Die Blutprobensätze von 30 Tieren, bei denen zu allen vier Zeitpunkten Blut gewonnen wurde, wurden zudem auf die Konzentrationen von Cholecalciferol, 25-Hydroxycholecalciferol (25OHD3), 1,25-Dihydroxycholecalciferol (1,25(OH)2D3) und 24,25-Dihydroxycholecalciferol (24,25(OH)2D3) untersucht, um die Metabolisierung des Cholecalciferols im Organismus nachvollziehen zu können. Nach Ende des Beobachtungszeitraums (Mai 2022 bis September 2023) wurden die gesammelten Milchleistungsdaten und Reproduktionsparameter ausgewertet.
Die Injektion von 10 Mio. I.E. Cholecalciferol sieben Tage vor der Kalbung hatte keinen Einfluss auf die Milchleistung in der Folgelaktation (P = 0,67). Die Tiere der Behandlungsgruppe hatten tendenziell höhere Serum-Ca-Werte in den ersten drei Tagen p.p (P = 0,08). Es konnten außer einer erhöhten Inzidenz von Retentio secundinarum in der Behandlungsgruppe (Kontrolle: 7,9%, Behandlung: 14,8%, P = 0,02) keine Auswirkungen der Cholecalciferol-Injektion auf die Inzidenzen von Totgeburten, klinischer Hypocalcämie und Metritis sowie die Milchleistungsdaten und Reproduktionsparameter beobachtet werden.
Die Analyse der Konzentrationen von Progesteron und Östradiol vor der Kalbung ergab keine Unterschiede zwischen den beiden Gruppen (P = 0,81). Die Hypothese aus einer ähnlich aufgebauten Studie von Venjakob et al. (2022) mit Fütterung einer negativen DCAB in der Vorbereiterration, dass die Cholecalciferol-Injektion den Steroidhormonmetabolismus dahingehend beeinflusst hätte, dass es zu einem frühzeitigen Abbau von Progesteron zu Östradiol und damit zu einer vorzeitigen Initiierung der Abkalbung gekommen sein könnte, konnte anhand dieser Ergebnisse nicht bestätigt werden.
Die Untersuchung der Blutproben auf den Gehalt von Cholecalciferol, 25OHD3, 1,25(OH)2D3 und 24,25(OH)2D3 ergab einen etwa 100-fachen Anstieg der Cholecalciferol-Konzentration auf 464,0 ng/ml zwei Tage nach der Injektion und einen vierfachen Anstieg der 25OHD3-Konzentration auf bis zu 205,5 ng/ml in den ersten drei Tagen p.p. in der Behandlungsgruppe. Die 1,25(OH)2D3-Konzentration im Serum der mit Cholecalciferol behandelten Tiere erreichte fünf Tage vor der Kalbung deutlich höhere Werte (89,2 pg/ml) als bei den mit einem Placebo behandelten Tieren (34,9 pg/ml). Nach der Kalbung zeigte jedoch die 1,25(OH)2D3-Konzentration in der Kontrollgruppe einen stärkeren Anstieg (Behandlung: 122,9 pg/ml; Kontrolle: 166,0 pg/mL an Tag zwei p.p.), sodass der 1,25(OH)2D3-Wert an Tag drei p.p. in der Kontrollgruppe signifikant höher lag (Behandlung: 101,6 pg/ml; Kontrolle: 155,6 pg/ml; P < 0,05). Diese Ergebnisse zeigen, dass die Wirkung der Cholecalciferol-Injektion auf den Serum-Ca-Spiegel p.p. in der vorliegenden Untersuchung vermutlich durch 25OHD3 vermittelt wurde.
Insgesamt zeigen die Resultate dieser Untersuchung, dass die Kombination einer Injektion von 10 Mio. I.E. Cholecalciferol ca. sieben Tage vor der erwarteten Kalbung und der Fütterung einer kationenreichen Ration in der Trockenstehphase zu deutlich geringeren Auswirkungen auf die Serumdynamik von Ca und Pi als die Kombination mit einer Vorbereiterration mit negativer DCAB führte. Es konnten abgesehen von einer höheren Inzidenz von Retentio secundinarum in der Behandlungsgruppe dennoch keine negativen Effekte auf die Inzidenz von Metritis sowie die Milchleistung und Güstzeit in der Folgelaktation nachgewiesen werden.Hypocalcemia is a common metabolic disorder in dairy cows up to 48 hours after calving. In particular, subclinical hypocalcemia often described as a gateway disease predisposes the cow to numerous subsequent diseases and thus leads to major economic losses. Injectable cholecalciferol is used for prevention of hypocalcemia in pluriparous dairy cows since the 1970s (Gürtler et al. 1977). The injection was recommended to be performed approximately five to seven days before the expected parturition, in order to activate calcium metabolism already before calving as the calcium demand increases dramatically at the onset of lactation.
In the present study we investigated the effect of a treatment with an intramuscular injection of 10 x 106 IU of cholecalciferol on serum dynamics of calcium, phosphorus and magnesium after calving as well as on milk production and reproductive parameters in subsequent lactation. For this purpose, 446 pluriparous dairy cows of 11 farms in northwest Germany received a diet with positive DCAD during the dry period and were treated with an intramuscular injection of 10 x 106 IU of cholecalciferol or a placebo (10 ml of NaCl 0,9%) seven days before calving. After parturition, calving related data were recorded (i.e. calving ease, stillbirth, twins) and cows were monitored for retained placenta and clinical signs of hypocalcemia. In a subsample of 95 animals, blood samples were drawn on 1st, 2nd, and 3rd DIM and analyzed for serum calcium, phosphorus and magnesium concentration. All animals were examined once between 5 to 10 DIM for signs of metritis. In 38 animals, an additional blood sample was drawn 2 days after the injection for determination of the progesterone and estrogen concentration. Blood samples of 30 animals drawn 2 days after injection and on 1st, 2nd, and 3rd DIM were also analyzed for cholecalciferol, 25-hydroxycholecalciferol (25OHD3), 1,25-dihydroxycholecalciferol (1,25(OH)2D3) and 24,25-dihydroxycholecalciferol (24,25(OH)2D3) concentrations to evaluate cholecalciferol metabolism. At the end of the observation period (May 2022 to September 2023), the effect of cholecalciferol treatment on milk production and reproduction parameters in subsequent lactation were analyzed.
The injection of 10 x 106 IU cholecalciferol had no effect on milk production in subsequent lactation (P = 0.67). Animals in the treatment group tended to have higher serum Ca levels during the first three days after calving (P = 0.08). Beside a higher incidence of retained placenta in the treatment group (control: 7.9%, treatment: 14,8%, P = 0.02), no effects of the treatment with cholecalciferol on the incidence of stillbirths, clinical hypocalcaemia, metritis, days to pregnancy and culling risk were observed.
Analyses of progesterone and oestrogen concentrations before calving revealed no differences between the two groups (P = 0,81). The hypothesis from a similar investigation that cholecalciferol treatment may result in an early degradation of progesterone to estrogen and therefore shortened gestation length (Venjakob et al., 2022) could not be confirmed. In this study, however, close-up cows were fed with a negative DCAD diet.
Analysis of blood samples for serum cholecalciferol, 25OHD3, 1,25(OH)2D3 and 24,25(OH)2D3 revealed an approximately 100-fold increase in serum cholecalciferol concentrations of treated animals to 464.0 ng/ml two days after injection and a 4-fold increase in serum 25OHD3-concentration up to 205.5 ng/ml at the first three DIM in the treatment group. The serum 1,25(OH)2D3 concentration in the treatment group (89.2 pg/ml) was five days before calving significantly higher than in the control group (34.9 pg/ml). After calving the serum 1,25(OH)2D3 concentration in the control group showed a greater increase (treatment: 122.9 pg/ml; control: 166.0 pg/ml on day two p.p.). On 3rd DIM the 1,25(OH)2D3 concentration was significantly higher in the control group (treatment: 101.6 pg/ml; control: 155.6 pg/ml; P < 0.05). These results indicate that the effect of cholecalciferol treatment on serum Ca levels p.p. in the present study was probably mediated by 25OHD3.
Overall, the results of this study show, that the combination of an antepartum injection of 10 x 106 IU of cholecalciferol approximately seven days before the expected calving and a positive DCAD during the dry period led to much smaller effects on the serum dynamics of calcium and phosphorus than the combination with an negative DCAD diet. Apart from a higher incidence of retained placenta in the treatment group, there were no negative effects on the incidence of metritis, milk production and time to pregnancy in subsequent lactation
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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