The Dairy Authority Lab
Bovine Leukemia Virus (BLV)
Bovine Leukemia Virus is the causative agent of bovine leukosis, a highly fatal form of cancer in cattle. Clinical signs are often absent until the extremely late stages of the disease. Late stage leucosis is characterized by lymphadenopathy(enlarged lymph nodes) in various regions of the body, commonly in the subiliac(pelvic) region. These tumors are often found by rectal exam. Tumors can also often be found in the abomasum, uterus and the spine.
Once infected with BLV virus, cattle are lifetime carriers and shedders of the virus. Virus is spread through animal to animal contact via blood, milk/colostrum and in-utero from dam to offspring. Also, an important means of transmission is though blood contamination of needles and surgical instruments as well as rectal sleeves used in multiple cows.
The BLV ELISA test is used to detect the presence of Anti-BLV antibodies in serum. A positive result indicates exposure to the virus. All positive animals will not necessarily develop tumors and may not be chronic carriers. Test results should be discussed with a veterinarian before any decision is made to sell or retain individuals or groups of cows based on test-positive status. There are numerous components of a BLV control program and veterinary consultation is recommended before any BLV control program is initiated.
To learn more about delivering samples to the lab, visit the Laboratory page.
Questions may also be submitted through our online contact form.