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Prevalence of Salmonella spp in cull (market) dairy cows at slaughter

H. Fred Troutt VMD, PhD, DACVN1, John C. Galland PhD2, Bennie I. Osburn DVM, PhD, DACVP3, Robert L. Brewer DVM4, R. Kenneth Braun DVM, MS, DACT5, John A. Schmitz DVM, PhD, DACVP6, Phil Sears DVM, PhD7, Asa B. Childers DVM, MS8, Ed Richey DVM9, Edward Mather DVM, PhD, DACT10, Michael Gibson PhD11, Kris Murthy DVM, MS, MVSE12, and Alan Hogue DMV, MS, DACVPM13
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  • 1 Food Animal Production Medicine Consortium, Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois, Urbana, IL 61802.
  • | 2 Food Animal Health and Management Center, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506.
  • | 3 Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, CA 95616.
  • | 4 USDA-FSIS, OPHS, Rm 392, Aerospace Center, Washington, DC 20250.
  • | 5 Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610.
  • | 6 Department of Veterinary and Biomedical Sciences, University of Nebraska, Lincoln, NE 68583.
  • | 7 Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824.
  • | 8 Department of Veterinary Anatomy and Public Health, College of Veterinary Medicine, Texas A&M University, College Station, TX 77843.
  • | 9 Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610.
  • | 10 Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824.
  • | 11 Department of Veterinary Anatomy and Public Health, College of Veterinary Medicine, Texas A&M University, College Station, TX 77843.
  • | 12 USDA-FSIS, OPHS, Rm 392, Aerospace Center, Washington, DC 20250.
  • | 13 USDA-FSIS, OPHS, Rm 392, Aerospace Center, Washington, DC 20250.

Abstract

Objective—To determine the prevalence of Salmonella spp in the cecal-colon contents of cull (market) dairy cows at slaughter because of potential public health ramifications.

Design—Survey study.

Sample Population—Cecal-colon contents collected from 5,087 cull (market) dairy cows at slaughter at 5 slaughter establishments across the United States.

Procedure—During 2 periods of the year, winter (January and February) and summer (July through September), 5 cull (market) cow slaughter establishments in the United States—west (WE), southeast (SEE), central (CE), north central (NCE), and south central (SCE)—establishments were visited, and cecalcolon contents of cull dairy cows were obtained at the time of slaughter. Samples were examined by microbiologic culture at a single laboratory for Salmonella spp.

ResultsSalmonella spp were detected in 23.1% of cecal-colon content samples from cull dairy cows across the 5 slaughter establishments. The highest site prevalence (54.5%) was detected at the WE during the summer period, whereas the lowest was found at the CE during the summer (4.3%) and at the NCE during the winter (4.5%). Considerable variation in the daily prevalence of Salmonella spp was found, particularly at the WE and the SCE. Salmonella spp were isolated from 93% of cecal-colon contents collected on a summer day at the WE.

Conclusions and Clinical Relevance—Results strongly suggest that there is a high prevalence of Salmonella spp in cull dairy cows at slaughter, which could burden Hazard Analysis Critical Control Point programs implemented in slaughter establishments. Procedures to reduce Salmonella load at the dairy farm and during transport to slaughter could reduce the risk of spread during the slaughter process. (J Am Vet Med Assoc 2001;219:1212–1215)

Abstract

Objective—To determine the prevalence of Salmonella spp in the cecal-colon contents of cull (market) dairy cows at slaughter because of potential public health ramifications.

Design—Survey study.

Sample Population—Cecal-colon contents collected from 5,087 cull (market) dairy cows at slaughter at 5 slaughter establishments across the United States.

Procedure—During 2 periods of the year, winter (January and February) and summer (July through September), 5 cull (market) cow slaughter establishments in the United States—west (WE), southeast (SEE), central (CE), north central (NCE), and south central (SCE)—establishments were visited, and cecalcolon contents of cull dairy cows were obtained at the time of slaughter. Samples were examined by microbiologic culture at a single laboratory for Salmonella spp.

ResultsSalmonella spp were detected in 23.1% of cecal-colon content samples from cull dairy cows across the 5 slaughter establishments. The highest site prevalence (54.5%) was detected at the WE during the summer period, whereas the lowest was found at the CE during the summer (4.3%) and at the NCE during the winter (4.5%). Considerable variation in the daily prevalence of Salmonella spp was found, particularly at the WE and the SCE. Salmonella spp were isolated from 93% of cecal-colon contents collected on a summer day at the WE.

Conclusions and Clinical Relevance—Results strongly suggest that there is a high prevalence of Salmonella spp in cull dairy cows at slaughter, which could burden Hazard Analysis Critical Control Point programs implemented in slaughter establishments. Procedures to reduce Salmonella load at the dairy farm and during transport to slaughter could reduce the risk of spread during the slaughter process. (J Am Vet Med Assoc 2001;219:1212–1215)