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Results of a longitudinal study of the prevalence of Escherichia coli O157:H7 on cow-calf farms

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  • 1 Food Animal Health and Management Center, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506-5606.
  • | 2 Food Animal Health and Management Center, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506-5606.
  • | 3 Food Animal Health and Management Center, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506-5606.
  • | 4 Animal Sciences and Industry, College of Agricultur, Kansas State University, Manhattan, KS 66506-5606.
  • | 5 Food Animal Health and Management Center, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506-5606.
  • | 6 Animal Sciences and Industry, College of Agricultur, Kansas State University, Manhattan, KS 66506-5606.
  • | 7 Food Animal Health and Management Center, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506-5606.

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.

Sample Population—Fecal and water samples for 10 cow-calf farms in Kansas.

Procedure—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.

ResultsEscherichia coli O157:H7 was detected in 40 of 3,152 (1.3%) fecal samples, and 40 of 2,058 (1.9%) cattle had ≥ 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 and Clinical Relevance—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. (Am J Vet Res 2000;61:1375–1379)