Predicting the effect of anthelmintic treatment on milk production of dairy cattle in Canada using an Ostertagia ostertagi ELISA from individual milk samples

Show simple item record Vanderstichel, Raphaël Dohoo, Ian Sanchez, Javier Sithole, Fortune Keefe, Gregory Stryhn, Henrik 2013-10-30T08:23:03Z 2013-10-30T08:23:03Z 2013-08
dc.description.abstract Gastrointestinal nematodes, such as Ostertagia ostertagi and several species of Cooperia, are ubiquitous in temperate climates and have been shown to have detrimental effects on production in adult dairy cattle. A published meta-analysis demonstrated that overall, producers lose approximately 0.35 kg of milk per parasitized cow per day. Enzyme-linked immunosorbent assays (ELISAs) have the ability to quantify nematode infections in cattle, and thus, could be used to estimate the amount of milk production loss due to differing levels of parasitism at the individual cow level. ELISA results from individual cow milk samples were used to predict milk production response following a randomized anthelmintic treatment in a large field trial. To increase statistical power, the data collected from this field trial was pooled with data from two other published field trials to form an individual patient data meta-analysis (IPDMA). The ability to predict the effect of anthelmintic treatment on milk production depends on the level of parasitism quantified by an ELISA measuring milk antibodies against O. ostertagi, and reported as optical density ratios (ODRs). Therefore, the estimates from the interaction between ODR and treatment on milk production were used to determine how well the ODR predicted the response of the treatment. It was anticipated that the relationship between milk production and ODR was unlikely to be linear, so fractional polynomials were applied to the continuous ODR values. The interaction in the field trial showed a trend (p = 0.138) toward a beneficial treatment effect when the individual ODR values, measured in late lactation and using Svanovir®, were greater than 0.12. When individual data from two other similar studies were included in an IPDMA, the interaction terms became statistically significant (p = 0.009) indicating that there is a beneficial treatment effect when ODR values are slightly elevated. A graph was used to demonstrate the treatment effect (the estimated difference of kg/cow/day of milk yield between the treated and placebo cows), with 95% confidence intervals, as the ODR values increase. It is important to note that the methods of quantifying the ODR values differed between the three studies in the IPDMA, therefore some caution should be used when using these final estimated values. However, the shape and magnitude of the treatment effects, as well as the other fixed model estimates, were very similar between the field trial and the IPDMA suggesting that any bias would likely be minimal. en
dc.description.librarian hb2013 en
dc.description.librarian mn2013
dc.description.sponsorship Merial Canada Inc., the Dairy Farmers of Canada, Maritime Quality Milk, the Natural Sciences and Engineering Research Council of Canada, and the ELISA kits were provided by an in-kind contribution from Svanova Biotech AB. en
dc.description.uri en
dc.identifier.citation Vanderstichel, R, Dohoo, I, Sanchez, J, Sithole, F, Keefe, G & Stryhn, H 2013, 'Predicting the effect of anthelmintic treatment on milk production of dairy cattle in Canada using an Ostertagia ostertagi ELISA from individual milk samples', Preventive Veterinary Medicine, vol. 111, no. 1-2, pp. 63-75. en
dc.identifier.issn 0167-5877 (print)
dc.identifier.issn 1873-1716 (online)
dc.identifier.other 10.1016/j.prevetmed.2013.04.001
dc.language.iso en en
dc.publisher Elsevier en
dc.rights © 2013 Elsevier. All rights reserved. Notice : this is the author’s version of a work that was accepted for publication in Preventive Veterinary Medicine. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Preventive Veterinary Medicine, vol. 111, no. 1-2, 2013, doi : 10.1016/j.prevetmed.2013.04.001 en
dc.subject Cattle en
dc.subject Ostertagia ostertagi en
dc.subject Milk en
dc.subject Individual patient data meta-analysis en
dc.subject Fractional polynomial en
dc.subject Enzyme-linked immunosorbent assay en
dc.subject ELISA en_ZA
dc.subject.lcsh Nematodes -- Research en
dc.subject.lcsh Anthelmintics en
dc.subject.lcsh Cattle -- Diseases -- South Africa en
dc.title Predicting the effect of anthelmintic treatment on milk production of dairy cattle in Canada using an Ostertagia ostertagi ELISA from individual milk samples en
dc.type Postprint Article en

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