title: Results of a longitudinal study of the prevalence of Escherichia coli O157:H7 on cow-calf farms.
abstract: OBJECTIVE
  To describe the frequency and distribution of Escherichia coli O157:H7 in the feces and environment of cow-calf herds housed on pasture.
  
  
  METHODS
  Fecal and water samples for 10 cow-calf farms in Kansas.
  
  
  METHODS
  Fecal and water samples were obtained monthly throughout a 1-year period (3,152 fecal samples from 2,058 cattle; 199 water samples). Escherichia coli O157:H7 in fecal and water samples was determined, using microbial culture.
  
  
  RESULTS
  Escherichia coli O157:H7 was detected in 40 of 3,152 (1.3%) fecal samples, and 40 of 2,058 (1.9%) cattle had > or = 1 sample with E coli. Fecal shedding by specific cattle was transient; none of the cattle had E coli in more than 1 sample. Significant differences were not detected in overall prevalence among farms. However, significant differences were detected in prevalence among sample collection dates. Escherichia coli O157:H7 was detected in 3 of 199 (1.5%) water samples.
  
  
  CONCLUSIONS
  Implementing control strategies for E coli O157:H7 at all levels of the cattle industry will decrease the risk of this organism entering the human food chain. Devising effective on-farm strategies to control E coli O157:H7 in cow-calf herds will require an understanding of the epidemiologic characteristics of this pathogen.
authors: Food Animal Health and Management Center, College of Veterinary Medicine, Kansas State University, Manhattan 66506-5606, USA.
authors: J M
authors: JM
authors: Sargeant
authors: J R
authors: JR
authors: Gillespie
authors: R D
authors: RD
authors: Oberst
authors: R K
authors: RK
authors: Phebus
authors: D R
authors: DR
authors: Hyatt
authors: L K
authors: LK
authors: Bohra
authors: J C
authors: JC
authors: Galland
mesh_terms: D000822:Animal Husbandry / Q000379:methods; D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology* / Q000382:microbiology; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D019453:Escherichia coli O157 / Q000302:isolation & purification*; D005243:Feces / Q000382:microbiology; D005260:Female; D006799:Housing, Animal; D007615:Kansas / Q000453:epidemiology; D008137:Longitudinal Studies; D008297:Male; D015995:Prevalence; D012307:Risk Factors; D012621:Seasons; D014871:Water Microbiology