Bovine Leukosis: Welfare and Biosecurity Considerations
Enzootic bovine leukosis (EBL) is a slow-spreading retroviral disease causing lymphoma in cattle, with welfare and trade implications for affected herds.
Key Facts
- Caused by bovine leukemia virus (BLV), spread by blood and insect vectors
- Most infected cattle remain healthy carriers; around 5% develop lymphoma
- Lymphoma typically affects cattle over 4 years old, causing rapid deterioration
- EBL is an OIE-listed disease affecting international trade status
- Several countries have achieved EBL-free status through testing and culling programs
Welfare Considerations
Bovine leukosis welfare implications center on the minority of infected cattle that develop lymphoma. These cattle experience rapid deterioration, with enlarged lymph nodes causing external compression of airways, esophagus, and other structures. Affected animals show weight loss, decreased production, and progressive debilitation. The unpredictable nature of which infected animals will develop lymphoma makes individual prognosis challenging. Welfare management requires regular monitoring for clinical signs and prompt euthanasia of cattle showing signs of advanced lymphoma.
What You Can Do
- Participate in regional BLV testing and eradication programs
- Use single-use needles and equipment to prevent iatrogenic spread
- Monitor older cattle regularly for signs of lymphoma development
- Euthanize affected cattle promptly to prevent prolonged suffering
- Purchase cattle from accredited EBL-free herds when possible