Accuracy of the composite somatic cell count to detect intra-mammary infection in dairy cows using latent class analysis

Vissio, Claudina; Dieser, Silvana Andrea; Agnelli, Héctor; Odierno, Liliana; Larriestra, Alejandro

doi:10.1016/j.prevetmed.2013.11.016

Cited by 19 publications

(12 citation statements)

References 47 publications

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“…We used an elevated SCC as an indicator for the presence of an IMI (Schukken et al, 2003;Vissio et al, 2014). In line with the thresholds for elevated SCC used in Dutch national milk recording, primiparous cows with an SCC ≥150,000 cells/mL and multiparous cows with an SCC ≥250,000 cells/mL were classified as infected (de Haas et al, 2008).…”

Section: Scc Dynamics During the Dry Periodmentioning

confidence: 99%

“…By applying SDCT, only those cows with a higher risk of an IMI at dry-off are targeted with intramammary antimicrobial DCT. A commonly used threshold for the presence of an IMI is an SCC ≥200,000 cells/mL (Schukken et al, 2003;Vissio et al, 2014). The recommended thresholds for intramammary antimicrobial DCT described in the guideline on the use of antimicrobials at dry-off in dairy cattle in the Netherlands are below this level at 150,000 cells/mL (primiparous cows) and 50,000 cells/mL (multiparous cows; see Appendix for details).…”

Section: Scc Dynamics During the Dry Periodmentioning

confidence: 99%

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Effects of reduced intramammary antimicrobial use during the dry period on udder health in Dutch dairy herds

Vanhoudt

Hees-Huijps²,

Knegsel

et al. 2018

Journal of Dairy Science

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Dry cow therapy (DCT) in the Netherlands changed from mainly blanket to selective antimicrobial DCT. This transition was supported by a national guideline, with the individual somatic cell count (SCC) at the last milk recording before dry-off as the main selection criterion for antimicrobial DCT. The aim of this retrospective observational study is to evaluate the SCC dynamics during the dry period at the herd and individual dry period level following the national transition from mainly blanket to selective antimicrobial DCT. At the herd level, we used 2 data sets to evaluate the SCC dynamics during the dry period: (1) a national data set containing 3,493 herds with data available from 2011 through 2015 and (2) a veterinary practice data set containing 280 herds with data available from 2013 through 2015. The herd level analysis was carried out using key performance indicators provided via milk recording (CRV, Arnhem, the Netherlands): the percentage of cows that developed a new intramammary infection (IMI) during the dry period and the percentage of cows cured of an IMI during the dry period. The effect of DCT at individual dry period level was analyzed with a mixed-effects logistic regression model based on 4,404 dry periods from 2,638 cows in 20 herds within the veterinary practice data set. For these 20 herds, individual SCC data from milk recordings and individual cow DCT were available from 2013 through 2015. No significant changes were observed to the SCC dynamics during the dry period at the herd level. The percentage of cows that developed a new IMI during the dry period ranged between 16 and 18%, and the percentage of cows cured from an IMI during the dry period ranged between 74 and 76%. At the individual dry period level, a low SCC at the first milk recording following a dry period was associated with the use of intramammary antimicrobial DCT with or without the concurrent use of an intramammary teat sealer [odds ratio (OR) = 2.16 and OR = 2.07, respectively], the use of DCT with an intramammary teat sealer only (OR = 1.35), and a low SCC at the last milk recording before dry-off (OR = 1.78). This study demonstrates that the selection of cows for DCT without antimicrobials based on SCC thresholds at the last milk recording is possible without significant changes to udder health and reduced the use of antimicrobials.

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Section: Scc Dynamics During the Dry Periodmentioning

confidence: 99%

Section: Scc Dynamics During the Dry Periodmentioning

confidence: 99%

Effects of reduced intramammary antimicrobial use during the dry period on udder health in Dutch dairy herds

Vanhoudt

Hees-Huijps²,

Knegsel

et al. 2018

Journal of Dairy Science

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“…An option that enables circumventing this issue is represented by the LCA approach (Hui and Walter, 1980), which is based on a probabilistic cross-classification of results and provides a better estimate of Se and Sp of a novel diagnostic test in the absence of a true gold standard (Georgiadis et al, 2003). Latent class analysis is increasingly being implemented in the evaluation of methods for detecting mastitis and IMI (Dohoo et al, 2011;Koop et al, 2011;Fosgate et al, 2013;Vissio et al, 2014) For the latent class model to be applicable, 3 assumptions need to be satisfied: the prevalence differs among the populations examined, Se and Sp are constant across subpopulations, and the tests are conditionally independent from each other. Conditional independence among tests implies that when the disease status of a test subject is known, the probability of a test result is unaffected by the outcome of another test (Dawid, 1979;Toft et al, 2005).…”

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confidence: 99%

Evaluation of milk cathelicidin for detection of dairy sheep mastitis

Addis¹,

Tedde²,

Dore

et al. 2016

Journal of Dairy Science

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Mastitis due to intramammary infections is one of the most detrimental diseases in dairy sheep farming, representing a major cause of reduced milk productions and quality losses. In particular, subclinical mastitis presents significant detection and control problems, and the availability of tools enabling its timely, sensitive, and specific detection is therefore crucial. We have previously demonstrated that cathelicidins, small proteins implicated in the innate immune defense of the host, are specifically released in milk of mastitic animals by both epithelial cells and neutrophils. Here, we describe the development of an ELISA for milk cathelicidin and assess its value against somatic cell counts (SCC) and bacteriological culture for detection of ewe mastitis. Evaluation of the cathelicidin ELISA was carried out on 705 half-udder milk samples from 3 sheep flocks enrolled in a project for improvement of mammary health. Cathelicidin was detected in 35.3% of milk samples (249/705), and its amount increased with rising SCC values. The cathelicidin-negative (n=456) and cathelicidin-positive (n=249) sample groups showed a clear separation in relation to SCC, with median values of 149,500 and 3,300,000 cells/mL, respectively. Upon bacteriological culture, 20.6% (145/705) of the milk samples showed microbial growth, with coagulase-negative staphylococci being by far the most frequent finding. A significant proportion of all bacteriologically positive milk samples were positive for cathelicidin (110/145, 75.9%). Given the lack of a reliable gold standard for defining the true disease status, sensitivity (Se) and specificity (Sp) of the cathelicidin ELISA were assessed by latent class analysis against 2 SCC thresholds and against bacteriological culture results. At an SCC threshold of 500,000 cells/mL, Se and Sp were 92.3 and 92.3% for cathelicidin ELISA, 89.0 and 94.9% for SCC, and 39.4 and 93.6% for bacteriological culture, respectively. At an SCC threshold of 1,000,000 cells/mL, Se and Sp were 93.3 and 91.9% for cathelicidin ELISA, 80.0 and 97.1% for SCC, and 39.4 and 93.5% for bacteriology, respectively. In view of the results obtained in this study, the measurement of cathelicidin in milk by ELISA can provide added Se while maintaining a high Sp and may therefore improve detection of subclinical mastitis.

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“…60,66 Cell counts below this threshold in composite milk samples indicate that a mammary gland is likely to be free of IMI, 15 but this threshold is based on the assumption that the culture test is perfect, which does not take into account the chances of false-negative results in a SCC ≤200,000 cells/mL. Therefore, a study 77 determining the accuracy of both SCC and culture to detect IMI proposes a lower threshold of 150,000 cells/mL, which can account for misclassification of the culture. The authors of that study suggest this is a more accurate SCC cutoff, providing information about the prevalence of subclinical mastitis corresponding to test sensitivity and specificity maximization.…”

Section: Mastitis Detectionmentioning

confidence: 99%

Technological advances in bovine mastitis diagnosis

2015

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Abstract. Bovine mastitis is an economic burden for dairy farmers and preventive control measures are crucial for the sustainability of any dairy business. The identification of etiological agents is necessary in controlling the disease, reducing risk of chronic infections and targeting antimicrobial therapy. The suitability of a detection method for routine diagnosis depends on several factors, including specificity, sensitivity, cost, time in producing results, and suitability for large-scale sampling of milk. This article focuses on current methodologies for identification of mastitis pathogens and for detection of inflammation, as well as the advantages and disadvantages of different methods. Emerging technologies, such as transcriptome and proteome analyses and nano-and microfabrication of portable devices, offer promising, sensitive methods for advanced detection of mastitis pathogens and biomarkers of inflammation. The demand for alternative, fast, and reliable diagnostic procedures is rising as farms become bigger. Several examples of technological and scientific advances are summarized which have given rise to more sensitive, reliable and faster diagnostic results.

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Accuracy of the composite somatic cell count to detect intra-mammary infection in dairy cows using latent class analysis

Cited by 19 publications

References 47 publications

Effects of reduced intramammary antimicrobial use during the dry period on udder health in Dutch dairy herds

Effects of reduced intramammary antimicrobial use during the dry period on udder health in Dutch dairy herds

Evaluation of milk cathelicidin for detection of dairy sheep mastitis

Technological advances in bovine mastitis diagnosis

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