Disclosed are immunogenic compositions comprising a modified, live bovine viral diarrhea virus type lb (BVDV-lb), and methods for their use in the formulation and administration of therapeutic and prophylactic pharmaceutical agents. In particular, the invention provides immunogenic compositions and methods for preventing, treating, managing, and/or ameliorating a viral or microbial infection, or one or more symptoms thereof, including, for example, those infections giving rise to shipping fever, bovine respiratory disease complex, and/or bovine viral diarrhea, particularly in susceptible or infected animals.