Age, geographic, and temporal distribution of fecal shedding of Cryptosporidium parvum oocysts in cow-calf herds

Edward R Atwill, Eileen Johnson, Donald J. Klingborg, Gary M. Veserat, Gary Markegard, Wayne A. Jensen, David W. Pratt, Richard E. Delmas, Holly A. George, Larry C. Forero, Ralph L. Philips, Sheila J. Barry, Neil K. McDougald, Rhonda R. Gildersleeve, William E. Frost

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Abstract

Objective - To evaluate fecal shedding of Cryptosporidium parvum from California cow-calf herds with respect to age, geographic region, temporal effects, and association with watery feces. Animals - Cows and calves from 38 beef cow-calf operations. Procedure - Fecal specimens were collected and examined for C parvum oocysts, using immunofluorescent microscopy. Associations between age, geographic region, month of collection, watery feces, and likelihood of shedding C parvum were evaluated. Results - 3.9% of cattle were shedding C parvum oocysts. Prevalence of shedding among calves ranged from O to 13%, and was 0.6% among cattle ≥ 12 months old. The odds of shedding C parvum among 2-month-old calves were 41 times greater than among cattle > 4 months old. The odds of shedding C parvum among cattle tested in May were 8.7 times greater than among cattle tested during June, July, or August. The odds of infected individuals having watery feces were 3 to 4 times greater than for noninfected individuals, but the etiologic fraction was only 8 to 9%. Conclusions and Clinical Relevance - Substantial fecal shedding of C parvum by cow-calf herds was limited to calves 1 to 4 months old, with low prevalence detected in older animals. Risk of contamina-tion of watersheds with C parvum was limited to those periods when young calves were in the herd. Although the odds of having watery feces were greater for animals infected with C parvum than for noninfected animals, the low etiologic fraction suggests that most calves with watery feces were not infected with C parvum.

Original languageEnglish (US)
Pages (from-to)420-425
Number of pages6
JournalAmerican Journal of Veterinary Research
Volume60
Issue number4
StatePublished - Apr 1999

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ASJC Scopus subject areas

  • veterinary(all)

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Atwill, E. R., Johnson, E., Klingborg, D. J., Veserat, G. M., Markegard, G., Jensen, W. A., Pratt, D. W., Delmas, R. E., George, H. A., Forero, L. C., Philips, R. L., Barry, S. J., McDougald, N. K., Gildersleeve, R. R., & Frost, W. E. (1999). Age, geographic, and temporal distribution of fecal shedding of Cryptosporidium parvum oocysts in cow-calf herds. American Journal of Veterinary Research, 60(4), 420-425.