Bovine Leukosis: Welfare Implications in Dairy and Beef Cattle

Enzootic bovine leukosis (EBL) is a slow-progressing viral disease of cattle causing lymphoma and significant welfare impacts in affected animals. Control programmes vary widely between countries.

Key Facts

EBL is caused by bovine leukemia virus (BLV), affecting cattle worldwide
Up to 70% of cattle in some herds may be seropositive without showing clinical disease
A small proportion develop clinical lymphoma with severe welfare impacts
The disease is spread through blood contact including shared needles and rectal palpation
Many European countries have achieved EBL-free status through test-and-cull programmes

Welfare Considerations

While most BLV-infected cattle remain subclinical, those developing clinical lymphoma experience progressive organ failure, weight loss, and significant suffering. Lymphoma can affect multiple organ systems including the heart, spinal cord, and abomasum, causing a range of welfare-compromising conditions. Prolonged survival with untreated tumour progression causes chronic pain and debilitation. Early detection through surveillance and prompt euthanasia of clinically affected animals are essential welfare obligations.

What You Can Do

Participate in national EBL surveillance programmes if operating in endemic countries
Implement strict biosecurity to prevent BLV spread within herds including single-use needles
Monitor cattle for clinical signs of lymphoma and seek veterinary assessment promptly
Support breeding selection for BLV-resistance traits where these are available
Engage with national eradication programmes to achieve herd-level freedom from EBL