Preventive Veterinary Medicine

Latent class analysis of real time qPCR and bacteriological culturing for the diagnosis of Streptococcus agalactiae in cow composite milk samples



SOURCE: Ingrid H. Holmøy, Nils Toft, Hannah J. Jørgensen, Tormod Mørk, Liv Sølverød,. and Ane Nødtvedt


ABSTRACT: Streptococcus agalactiae (S. agalactiae) has re-emerged as a mastitis pathogen among Norwegian dairy cows. The Norwegian cattle health services recommend that infected herds implement measures to eradicate S. agalactiae, this includes a screening of milk samples from all lactating cows. The performance of the qPCR-test currently in use for this purpose has not been evaluated under field conditions. The objective of this study was to estimate the sensitivity and specificity of the real-time qPCR assay in use in Norway (Mastitis 4 qPCR, DNA Diagnostics A/S, Risskov, Denmark) and compare it to conventional acteriological culturing for detection of S. agalactiae in milk samples. Because none of these tests are considered a perfect reference test, the evaluation was performed using latent class models in a Bayesian analysis. Aseptically collected cow-composite milk samples from 578 cows belonging to 6 herds were cultured and tested by qPCR. While 37 (6.4%) samples were positive for S. agalactiae by bacteriological culture, 66 (11.4%) samples were positive by qPCR.

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Journal of Dairy Science

Within-herd prevalence thresholds for herd-level detection of mastitis pathogens using multiplex real-time PCR in bulk tank milk samples



SOURCE: J. B. Soltau, E. Einax, K. Klengel, J. Katholm, K. Failing, A. Wehrend, and K. Donat
ABSTRACT: The objective of the study was to assess the value of quantitative multiplex real-time PCR examination of bulk tank milk samples for bovine mastitis pathogens as a tool for herd level diagnosis. Using a logistic regression model, this study is aimed at calculating the threshold level of the apparent within-herd prevalence as determined by quarter milk sample cultivation of all lactating cows, thus allowing the detection of a herd positive for a specific pathogen within certain probability levels. A total of 6,335 quarter milk samples were collected and cultured from 1,615 cows on 51 farms in Germany. Bulk tank milk samples were taken from each farm and tested by bacterial culture as well as the commercial PCR assay Mastit 4A (DNA Diagnostic A/S, Risskov, Denmark) identifying Staphylococcus aureus, Streptococcus dysgalactiae, Streptococcus agalactiae, and Streptococcus uberis.

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Journal of Dairy Science

Within-herd prevalence of intramammary infection caused by Mycoplasma bovis and associations between cow udder health, milk yield, and composition

Published online: June 7, 2017

SOURCE: Anri A.E. Timonen, Jørgen Katholm, Anders Petersen, Kerli Mõtus, Piret Kalmus
ABSTRACT: Subclinical mastitis is one of the major health problems in dairy herds due to decreased milk production and reduced milk quality. The aim of this study was to examine the within-herd prevalence of subclinical intramammary infection caused by Mycoplasma bovis and to evaluate associations between M. bovis and cow daily milk yield, udder health, and milk composition. Individual cow composite milk samples (n = 522) were collected from all lactating dairy cows in 1 Estonian dairy farm in November 2014. Daily milk yield, days in milk, and parity were recorded. Collected milk samples were analyzed for somatic cell count, milk protein, fat, and urea content.

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ICAR The Global Standard For Livestock Data

Proceedings of the 40th ICAR Biennial Session held in Puerto Varas, Chile, 24-28 October 2016


SOURCE: J. Katholm and A. Pedersen, DNA Diagnostic
The use of Real-time PCR tests to identify mastitis pathogenes are growing, as they are faster and more sensitive than conventional bacteriological culturing, especially for Mycoplasma detection. Since 2014 a quantitative real-time PCR test kit (Mastit 4, DNA diagnostic) has been commercially available. the objective of this study was to investigate the correlation between Ct values of the Mastit 4 PCR test kit for and bacterial colony forming units (CFU) in fresh milk samples for the 11 bacteria that can be detected by the Mastit 4 BDF, CFU, PCR test kit.

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NMC Annual Meeting Proceedings (2017)

Providing Routine PCR Testing as Part of Official Milk Recordings Options


SOURCE: Angela Dawn Coburn, Agsource Cooperative Service, Verona, Wisconsin USA
Introduction: Obtaining Somatic Cell Count (SCC) value from routine milk sample analysis is, historically, a primary reason U.S. dairy producers participate in official milk recordings program. With improves management of environmental conditions and general cow health, SCC levels have shown a steady decline over the past 4 years. Among Agsource herds, weighted average SCC for Holstein have dropped from 263,000 in 2012 to 227,000 in 2016. The percent of cows with SCC over 200,000 SCC has dropped from 24,3 % to 20,4 %.

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Jena at IDF Nantes Mastitis Conference (2016)

Jena at IDF Nantes Mastitis conference


SOURCE: J. B. Soltau, E. einax, K. Klengel, K. Donat, Animal Health Service, Thuringian animal Diseases Fund, Jena, Thuringia Germany. J. Katholm, DNA diagnostic, Risskov Denmark. K. Failing, Unit for Biomathermatics and Data Processing, Justus-liebig University, Giessen, Hesse Germany. A. Wehrend, Clinic of Obstetrics, gynaecology and Andrology for small and large Animals, Justus-Liebig University, Giessen, Hesse Germany.
Introduction: The aim of the study was to analyse the value of a polymerase chain reaction (PCR) examination of bulk tank samples for bovine mastitis pathogens as a tool to estimate the within herd prevalenceof these pathogens.
A total of 6,335 quarter milk samples were collected from 1,615 cows farms in Germany. Additionally, two bulk tank milk samples were collected from each farm. The quarter milk samples were cultivated in the laboratory of Animal Disease Fund (Jena, Thuringia, Germany). The bulk tank milk samples were tested by the commercial PCR assay Mastit 4 (DNA Diagnostic, Denmark) that identified Staphylococcus aureus, Streptococcus dysgalactiae, Streptococcus agalactiae and Streptocuccus uberis.

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NMC Annual Meeting Proceedings (2016)

Test characteristics of the qPCR test Mastit 4 to identify Major Pathogenes in spiked and originally infected Milk samples.


SOURCE: Torben W. Bennedsgaard, Line Svennesen, Ilka C. Klaas Aarhus University, Foulum Denmak and University of Copenhagen Denmark
Introduction: Real-time PCR tests are increasingly used to identify mastitis pathogenes as they are faster and more sensitive than conventional bacteriogical culturing. Recently a new commercially availeble quantitative real-time PCR test kit (Mastit 4, DNA Diagnostic) was introduced in Denmak and is mainly used to test cows prior to dry -off for subclinical intramammary infections or in herd screenings for eradication of Streptocuccus agalactiae. The objective of our study was to investigate the association between ct values of the Mastit 4 PCR test kit for and colony forming units in fresh milk samples from quaters without clinical mastitis for Streptocuccus agalactiae, Staphylocuccus aureus, Streptocuccus uberis and Streptococcus dysgalactiae.

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NMC Annual Metting Proceedings (2015)

Bulk Tank milk Surveillance For Contagios Mastitis Pathogenes: Comparison Of Two Commercial Real-Time PCR Test Kits


SOURCE: Erik Rattenborg, Carl O. Paulrud, Søren K. S. Jensen and Jørgen Katholm
Knowledge center for agriculture, Cattle, Aarhus N, Denmak
Eurofins, Vejen, Denmark
DNA diagnostic, Risskov, Denmark
As part of the Danish Surveillance program for Streptococcus agalactia. bulk tank milk (BTM) samples from all dairy herds are tested annually. since 2009 the bulk tank samples has been analyzed using real-time PCR PathoProof Mastitis assay (Thermo fisher Scientific, Vantaa, Fiinland) In 2009 and 2010 the analyses were carried out with the complete 12 Kit and in 2011-2013 with the complete 16 kit. Indseptember 2014 the real-time PCR Mastit 4 B (DNA Diagnostic, risskov, Denmark) was made commercially availeble. the objective of this study was to compare the PathoProof Mastitis Complete 16 kit with the Mastit 4b kit regarding the detection of four species of bacteria tested by both test (Staphylococcus aureus, Streptococcus agalactiae, Streptococcus uberis and Mycoplasma bovis) the comparison reveals essential knowledge tha may be used in designing the future surveillance program.

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