Bovine leukemia virus (BLV) is preventable. One-third of the nation’s beef cattle and nearly half of all dairy cattle are infected with the lifelong, incurable virus. In the 1960s and 70s, only 10% of dairy cattle were infected. It is estimated that more than 20 countries have eradicated this virus by culling all cattle with BLV antibodies.

The virus comprises cattle immune systems, leading to a 23% higher chance of being culled or dying than their healthy herd mates. Poor cow longevity is an animal welfare issue and an economic concern. However, a new laboratory test can measure a cow’s BLV proviral load (PVL) – the concentration of infectious BLV provirus in the blood and other body fluids. PVL testing can discern which cattle are responsible for most new infections and can be removed from the herd. Upon doing so, BLV rates drop rapidly.

Read more on BLV prevention and testing here.