Cow #13 and Her Calf

Cow #13 was experimentally infected with M. paratuberculosis by feeding it a low dose (one million bacterial cells) in its evening bottle of milk on each of three nights. Three years later she had a calf.

At calving, cow #13 was somewhat thinner than the non-infected control cows, but not extremely so. She developed diarrhea shortly after calving and the diarrhea persisted but was never watery. Two months after calving cow #13 was euthanized. M. paratuberculosis was isolated from the milk of this cow and from multiple internal organs. The calf was euthanized at 5 months of age and was found to be infected with M. paratuberculosis.

The pattern of diagnostic test results (351.6K) and the pathology seen at necropsy (mesenteric lymph nodes, 351.6K) (thick, corrugated ileum, 351.6K) are shown in other photographs.

This experimental infection illustrated several features of paratuberculosis in cattle:

1. Infected animals can appear normal, eat well, and have calves.
2. In the late stage of infection, M. paratuberculosis is excreted in milk.
3. In late stage of infection, the M. paratuberculosis infection is disseminated to several internal organs.
4. Calves born to infected cows have a high probability of becoming infected, particularly if they stay with their mother and nurse naturally.

Top of Page
Back to Photo Home Page

All material Copyright © 1996 by the Board of Regents of the University of Wisconsin System. School of Veterinary Medicine, all rights reserved. If you have questions or comments about this page email us at: collinsm@svm.vetmed.wisc.edu