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Vet. Res.
Volume 36, Number 1, January-February 2005
Page(s) 101 - 116
How to cite this article Vet. Res. (2005) 101-116
Vet. Res. 36 (2005) 101-116
DOI: 10.1051/vetres:2004055

High milk neutrophil chemiluminescence limits the severity of bovine coliform mastitis

Jalil Mehrzada, b, c, Luc Duchateaua and Christian Burvenicha

a  Ghent University, Faculty of Veterinary Medicine, Department of physiology, Biochemistry and Biometrics, Salisburylaan 133, 9820 Merelbeke, Belgium
b  McGill University, Department of Animal Science, Macdonald-Stewart Building 21, 111 Lakeshore Road, Ste. Anne de Bellevue, H9X 3V9, Quebec, Canada
c  Dairy and Swine Research and Development Centre, Agriculture and Agri-Food Canada, PO Box 90, 2000 Route 108 East, Lennoxville, J1M 1Z3, Quebec, Canada

(Received 20 May 2004; accepted 12 August 2004)

Abstract - Polymorphonuclear neutrophil (PMN) function changes during mastitis. To investigate the contribution of milk PMN to the severity of Escherichia coli (E. coli) mastitis, chemiluminescence (CL) of blood and milk PMN and their efficiency to destroy coliform bacteria in the mammary gland were examined following the induction of E. coli mastitis in early lactating cows. To better assess and define the degree of mastitis severity, cows were classified as moderate and severe responders according to milk production loss in the non-infected quarters at post-infection hour (PIH) 48. There was an inverse relationship between pre-infection milk PMN CL and colony-forming units at PIH 6. In moderate cows, the pre-infection blood and milk PMN CL was ~ 2-fold higher than that of severe cows. The probability of severe response increased with decreasing pre-infection PMN CL. At the beginning of the infection blood and milk PMN CL was consistently higher, and milk PMN CL increased faster after infection in moderate cows. At PIH > 48 milk PMN CL in severe cows exceeded that of moderate cows. The somatic cell count (SCC) in moderate cows increased faster than colony-forming units, whereas in severe cows the results were reversed. The kinetics of CL activity for blood and milk PMN before and during the early phase of infection confirmed an impairment in PMN CL activity for severe responding cows. High pre-infection blood and milk PMN CL and the immediate increase of milk PMN CL and SCC after infection limited bacterial growth thereby facilitating the recovery of E. coli mastitis in moderate cows. Our study strengthens the idea that pre-existing milk PMN (a static part of the udder's immune defense) functions as a "cellular antibiotic" before and during infection, and low milk PMN CL is a risk factor for bovine coliform mastitis.

Key words: bovine / chemiluminescence / mastitis / neutrophil / severity

Corresponding author: Christian Burvenich

© INRA, EDP Sciences 2005