Animal and farm influences on the dynamics of antibiotic resistance in faecal Escherichia coli in young dairy calves

A. C B Berge, Edward R Atwill, W. M. Sischo

Research output: Contribution to journalArticle

66 Scopus citations


It is believed that the intensive use of antibiotics in the management of disease in pre-weaned calves contributes to high levels of antibiotic resistance in commensal and pathogenic bacteria. We described the temporal dynamics of antibiotic-susceptibility patterns seen in bovine enteric Escherichia coli in pre-weaned calves on dairy farms and dedicated calf-rearing facilities. Cohorts of 30 calves at each of six farms were sampled at 2-week intervals during the pre-weaning period. Faecal E. coli isolates were analyzed for antibiotic susceptibility to 12 antibiotics with the disk-diffusion method and grouped using cluster analysis of inhibition-zone patterns. The influences of calf age, farm-type, and individual-calf antibiotic therapy on the clusterings were assessed using stratified analyses and cumulative multinomial logistic regression using generalized estimating equation with antibiotic-resistance cluster as an ordinal-dependent variable. The model controlled for farm and cohort by a nested design and included a repeated measure on calf at each sampling occasion. E. coli from calves 2 weeks of age were more likely to be increasingly multiply resistant than E. coli from day-old calves (OR = 53.6), as were 4- and 6-week-old calves (OR = 29.8 and 16.4, respectively). E. coli from calves on dedicated calf-rearing facilities were more likely to be increasingly multiply resistant than E. coli from dairy-reared calves (OR = 2.4). E. coli from calves treated with antibiotics within 5 days prior to sampling were also more likely to be increasingly multiply resistant than E. coli from calves not exposed to individual antibiotic therapy (OR = 2.0).

Original languageEnglish (US)
Pages (from-to)25-38
Number of pages14
JournalPreventive Veterinary Medicine
Issue number1-2
StatePublished - Jun 10 2005



  • Antibiotic exposure
  • Antibiotic resistance
  • Cluster analysis
  • Dairy calves
  • Multinomial logistic regression

ASJC Scopus subject areas

  • Animal Science and Zoology
  • veterinary(all)

Cite this