Student Case Presentation
Chronic Weight Loss and Diarrhea in a Postpartum Angus Cow: Diagnosis of Johne’s Disease
| Date/Time: |
8/27/2026 Poster 07
|
| Presenter: |
Haley Konoval |
| Veterinary School: |
UCD |
Abstract:
A 3-year-old postpartum Angus beef cow from the UC Davis Beef Barn was presented to the UC Davis Herd Health Service for evaluation of chronic weight loss and persistent diarrhea. The cow had calved two weeks prior and was dewormed at that time. The calf was undersized and required milk replacer supplementation. Despite treatment, diarrhea and progressive weight loss persisted, although appetite and water intake remained normal.
On physical examination, the cow was bright, alert, and responsive with normal vital parameters and no clinical dehydration. Notable findings included severe muscle wasting with prominent ribs and tuber coxae, decreased rumen fill, and a fecally contaminated hair coat. Rumen motility was reduced (1 contraction per minute). Rectal examination revealed profuse watery diarrhea. The uterus was appropriately involuting for the postpartum period. The mammary gland was underfilled, consistent with agalactia. Peripheral lymph nodes were within normal limits.
Based on the clinical presentation of chronic weight loss and diarrhea with preserved appetite, Johne’s disease was prioritized as a primary differential. Fecal real-time PCR was selected due to its high sensitivity in clinically affected animals. Testing was positive for Mycobacterium avium subspecies paratuberculosis (MAP) and negative for Salmonella spp., confirming Johne’s disease.
Management recommendations included immediate calf separation, isolation of the affected cow, and supportive oral electrolyte therapy. Due to the grave prognosis and risk of herd transmission, the cow was culled.
This case highlights the importance of early recognition of Johne’s disease and its significant herd-level implications. Prompt diagnosis enables implementation of targeted control measures, including test-and-cull strategies, improved calving area hygiene, and reduction of fecal-oral transmission to susceptible calves. Veterinarians play a critical role in guiding producers in biosecurity, surveillance, and management practices to mitigate the impact of MAP and maintain herd health and productivity.
