Reproductive consequences of infection with bovine viral diarrhea virus

Bovine viral diarrhea virus (BVDV) has emerged as one of the most important infectious disease agents in cattle [1,2]. The insidious nature of BVDV has led to substantial economic losses in both the dairy and beef industry on a worldwide level [3,4]. Contrary to its name, BVDV has been associated with pathology in several physiologic systems including the respiratory, hematologic, immunologic, neurologic, and reproductive systems. Reproductive losses may be the most economically important consequence associated with BVDV infection and evidence suggests the incidence of BVDV-related reproductive losses are increasing in the United States [5]. In addition to reduced reproductive efficiency, BVDV uses the reproductive system to maintain and spread itself in the cattle population by inducing immunotolerance following fetal infection. resulting in birth of calves persistently infected (PI) with the Virus. Cattle PI with BVDV are the major source of virus spread within and between farms. Reproductive losses associated with BVDV infection was described by Olafson et al in the first clinical description of BVDV [6]. In this report, pregnant cows subclinically infected with BVDV often aborted 10 to 90 days later. Since that time, it has become evident that BVDV can cause a wide array of reproductive losses that are largely dependent on the time of gestation where infection Occurs and the virus strain (Fig. 1). The purpose of this article is to review the effects of BVDV on reproduction.