How to cite this article: Vet. Res. (2008) 39:23
DOI: 10.1051/vetres:2007060

Association between Coxiella burnetii shedding in milk and subclinical mastitis in dairy cattle

John Barlow¹, Brad Rauch², Frank Welcome², Sung Guk Kim³, Edward Dubovi³ and Ynte Schukken<sup>2, 3

1</sup>  Department of Animal Science, University of Vermont, Terrill Hall 570 Main Street Burlington, Vermont 05445, USA
²  Quality Milk Production Services, New York State College of Veterinary Medicine, Cornell University, 22 Thornwood Drive Ithaca, New York 14850, USA
³  Department of Population Medicine and Diagnostic Sciences , College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, USA

(Received 20 May 2007; accepted 19 November 2007; published online 7 February 2008)

Abstract - The objective of this research was to explore the potential association between Coxiella burnetii shedding in milk and chronic subclinical mastitis in dairy cattle. In two separate studies, we identified an association between PCR-based detection of C. burnetii in milk and chronic subclinical mastitis in lactating dairy cows. These studies were conducted in a commercial dairy herd where there was ongoing intensive monitoring of subclinical mastitis by aerobic bacteriology, but no prior knowledge or management of C. burnetii infections. In a case-control study, quarter level C. burnetii status determined by real-time quantitative PCR (RT-qPCR) was strongly associated with chronic subclinical mastitis as measured by milk somatic cell counts. In a subsequent cross sectional study, 147 (45%) of 325 lactating cows were positive for C. burnetii by RT-qPCR of composite milk samples. In a generalized linear model, accounting for the effect of covariates including aerobic intramammary infection status, C. burnetii PCR status was a significant predictor of linear somatic cell count score. In agreement with a small number of previous reports, this research provides evidence that there may be mammary gland specific manifestations of C. burnetii infections in dairy cattle.

Key words: Coxiella burnetii / dairy cattle / mastitis

Corresponding author: john.barlow@uvm.edu

© INRA, EDP Sciences 2008