Descriptive epidemiology of bovine leukemia virus among herds enrolled in a national study of the impacts of infection on dairy cow longevity and production

Abstract

Bovine leukemia virus (BLV) is a deltaretrovirus prevalent in approximately 80% of US dairy herds and 30% of US dairy cattle. Previous work by our research group and others has shown that BLV infection leads to decreased milk production, impaired immune response, and decreased longevity among positive dairy cattle. Much of this work was part of a 2010 study of 113 Michigan dairy herds. Our research group is currently undertaking a nationwide study of bovine leukemia virus, in which we will be enrolling 120 herds from 11 states. The objective of this study is to confirm our findings from Michigan on a broader national scope. The descriptive epidemiology of bovine leukemia virus among herds enrolled in this study are presented here.