It is well accepted that BVDV contributes to disease in feedlot cattle, most importantly BRD. Preliminary research indicates that PI animals are associated with an increased risk of treatment for BRD. If the excess disease observed is associated with acute BVDV infections, PI animals are, therefore, a significant source of virus for penmates. Other sources of exposure to BVDV include propagation and dissemination of acute infections, and immigration of new virus in acutely infected animals transported to the feedlot. More research is needed to better estimate excess morbidity associated with BVDV, partition this excess morbidity to exposure to PI animals or other sources, and estimate the economic burden of BVDV. Control measures (and as some have proposed, eventual eradication) can then be evaluated for their economic feasibility.
Loneragan GH: Proc Am Assoc Bov Pract Conf 36:52-55, 2003.