Eradication of Mycoplasma bovis infection from a dairy herd in Great Britain
Bicknell, S.R.; Gunning, R.F.; Jackson, G.; Boughton, E.; Wilson, C.D.
Veterinary Record 112(13): 294-297
1983
ISSN/ISBN: 0042-4900 PMID: 6845609 Document Number: 207056
A herd of 370 milking cows in which an outbreak of Mycoplasma bovis mastitis started in autumn 1977 [see DSA 40, 6072] was used in an eradication project lastng 104 wk. Initially, quarter milk samples from all cows were examined for bacteria, mycoplasmas and cell count. Between Jan. 1978 and Dec. 1979, quarter milk samples were taken at calving and drying-off, and occasionally to check previous clinical cases. Composite milk samples from the bulk tank were examined weekly throughout the 2 yr. A total of 59 cows were identified (47 by quarter milk sampling) as M. bovis excretors during the project, 2 being clinical cases at sampling, 17 having had previous clinical infection and 40 with subclinical infection. The last excretor was found during wk 55. 5 of the M. bovis excretors were identified at calving and 3 at drying-off. Bulk tank samples were continuously negative from wk 61 onwards. M. bovis was not found in any of 339 nasal swabs examined. Since some infected animals excrete M. bovis only at the calving stage, the importance of detecting infected calvers before they join the milking herd is emphasized.