Livestock

Enzootic Bovine Leukosis: Welfare and Control

How bovine leukaemia virus affects cattle welfare and how control programmes work.

Key Facts

Enzootic bovine leukosis is caused by bovine leukaemia virus (BLV)
The UK achieved BLV-free status — maintaining it requires vigilance
Most infected cattle remain subclinical — a proportion develop lymphoma
Lymphoma causes welfare compromise through tumour mass effects on multiple organs

Welfare Considerations

BLV-associated lymphoma causes progressive welfare decline — weight loss, lymphadenopathy, and organ dysfunction from tumour masses. In BLV-endemic countries, welfare management focuses on reducing transmission through hygiene around blood-contaminated procedures. Welfare-focused management in BLV-free countries maintains disease-free status through testing of imports and biosecurity.

What You Can Do

Ensure imported cattle are tested for BLV to maintain national disease-free status
Support national surveillance programmes that monitor for BLV incursion
Cull lymphoma-affected cattle promptly — no welfare-preserving treatment exists