(BLV, Leukosis, lymphoma, lymphosarcoma)
Bovine leukosis is a disease caused by infection with Bovine Leukosis Virus. This disease is the main cause of lymphoma in adult cattle. Lymphoma (lymphosarcoma) is a malignant cancer of the lymphatic system. Not all cattle that get infected with Bovine Leukosis Virus (BLV) develop cancer. Those that do, show one or a few of different clinical signs, such as, chronic wasting and weight loss, infertility, sudden death, or neurologic disease. This virus is most commonly spread by dirty or reused needles, reusing palpation sleeves, and breeding. Some people believe that flies spread the Bovine Leukosis Virus and some cows are genetically prone to this disease; however, there is little evidence in the scientific literature to support these claims.
-What is Bovine Leukosis?
Bovine Leukosis is a disease caused by a virus called Bovine Leukosis Virus (abbreviated as BLV). This virus often causes a type of cancer called Malignant Lymphoma in adult cattle. Typically, 5-10% of infected cattle will develop Lymphoma and this risk increases with age.
-What are early warning signs of Bovine Leukosis?
Early warning signs are usually very subtle. If you keep good records, you may notice certain cows losing condition, decreasing pregnancy rates or affected cattle may take longer to breed.
-Signs of Bovine Leukosis in cows.
Cows can have one or more of the following:
1. Weight loss
3. Enlarged lymph nodes
4. Down or paralysed in the hind end
5. Difficulty or inability to get pregnant
-Is Bovine Leukosis contagious?
Although suspected, it has not been proven to be spread from one cow to another just from close contact. It can be transferred from a cow to her calf. It is commonly spread by reusing needles from one cow to another, reusing rectal or palpation sleeves, natural breeding, and some authors believe that biting flies tranmit the virus, although this has not been proven.
-Risk factors of Bovine Leukosis:
1. Reusing needles
2. Reusing palpation sleeves
3. Natural breeding infected cattle
4. Increasing age of the herd
5. Purchasing cattle from unknown sources or from herds known to be infected
-How serious is Bovine Leukosis?
BLV is life-threatening to the cattle that develop Malignant Lymphoma. Otherwise, it will decrease herd productivity and become economically damaging to a cattle operation.
-Can Bovine Leukosis impact my herd, or just affect one animal?
BLV can affect all animals in the herd.