Article Text

Aetiology of clinical mastitis in six Somerset dairy herds
  1. A. J. Bradley, MA, VetMB, PhD, DCHP, MRCVS1 and
  2. M. J. Green, BVSc, DCHP, MRCVS2
  1. 1 Department of Clinical Veterinary Science, Division ofAnimal Health and Husbandry, University of Bristol, Langford House, Langford, Bristol BS405DT
  2. 2 Orchard Veterinary Group, Wirral Park, Glastonbury, Somerset BA6 9XE


Clinical mastitis was monitored in six Somerset dairy herds for one year. The herds all had three-month geometric mean bulk milk somatic cell counts of less than 250,000 cells/ml. Escherichia coliwas the predominant pathogen isolated on all the farms and in all months of the year. Environmental pathogens accounted for 61-4 per cent of all cases of clinical mastitis and for 79-3 per cent of the mastitis cases in which an aetiological agent was identified. The mean annual incidence was 41-6 cases per 100 cows (range 14 to 75). Affected cows suffered a mean of 1-5 cases and 16-4 per cent of quarters suffered at least one repeat case. Mastitis due to E coliwas more severe than mastitis due to other causes and it tended to be more severe in early lactation and during the housing period. Mastitis was significantly more severe (grades 2 and 3) in the herd with the lowest bulk milk somatic cell count and in the herd which was kept indoors throughout the year than in the other four herds. Mastitis was fatal in 2-2 per cent of cases and resulted in the death of 0-6 per cent of the lactating cows.

Statistics from

Request permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.