Bovine leukemia virus: the silent thief

Abstract

Bovine Leukemia Virus (BLV) is the causative agent of enzootic bovine leukosis. Prevalence of BLV for dairy herds in North America is about 35 to 45% of cows, and slightly lower for beef (cow-calf) operations. The virus primarily targets B-lympho­cytes, causing disruptions in host cells that lead to altered leuk­ograms, immune dysfunction, and in a small minority of cases, lymphosarcoma. Depending on the stage of infection, affected dairy cattle may have decreased milk production and longevity, and the prevalence of infection within herds is associated with decreased productivity. This paper will offer a brief review the current understanding of this disease, and practical measures to monitor BLV prevalence in herds, as well as control measures that are pragmatic and economical.