Influence of dry period bacterial intramammary infection on clinical mastitis in dairy cows

M. J. Green*, L. E. Green, G. F. Medley, Y. H. Schukken, A. J. Bradley

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

153 Citations (Scopus)


Milk samples were taken from 1920 quarters (480 cows, six herds) on four occasions to examine the relationship between quarter level intramammary infection (IMI) during the dry period and clinical mastitis in the next lactation. All quarters were sampled at drying off and within 1 wk of calving, and two quarters from each cow were sampled both 0 to 7 and 8 to 14 d before calving. Milk samples were collected from all cases of clinical mastitis during the following lactation. Logistic regression models were developed to investigate the associations between IMI present during the sampling period and clinical mastitis. The probability of a quarter succumbing to clinical mastitis increased when Streptococcus dysgalactiae, Streptococcus faecalis, Escherichia coli, or Enterobacter spp. were cultured at drying off and when Escherichia coli, coagulase-positive staphylococcus, Serratia spp., or Streptococcus faecalis were cultured in two out of three late dry and post-calving samples. Quarters from which Corynebacterium spp. were isolated at drying off were at an increased risk of clinical mastitis, whereas the presence of Corynebacterium spp. in the late dry and post-calving samples was associated with a reduction in the risk of clinical mastitis. The risk of mastitis for specific pathogens increased if the same species of bacteria that had caused mastitis was isolated at least twice in the late dry and post-calving samples. Kaplan-Meier survival plots indicated that clinical mastitis associated with dry period infections was more likely to occur earlier in lactation than clinical mastitis not associated with dry period infections. There was evidence of quarter susceptibility to IMI or the possibility that infection with one organism led to clinical mastitis with another.

Original languageEnglish
Pages (from-to)2589-2599
Number of pages11
JournalJournal of Dairy Science
Issue number10
Publication statusPublished - Oct 2002

Bibliographical note

Funding Information:
We would like to thank the farmers and herdspersons involved in the study and the financial support of Leo Animal Health UK, Ltd . M. J. Green is supported by a BBSRC case studentship, and A. J. Bradley is supported by a Wellcome Trust fellowship.


  • Dry period
  • Intramammary infection
  • Mastitis

ASJC Scopus subject areas

  • Food Science
  • Animal Science and Zoology
  • Genetics


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