Pregnant cows can be vaccinated against bovine viral diarrhea virus (BVDV) using killed-virus (KV) vaccines. Modified-live virus (MLV) vaccines should be given when the cow is not pregnant -ideally 30-60 days prior to breeding. Some BVDV MLV products state on the label that they can be safely administered to pregnant cattle if the cattle had also received the same vaccine prior to breeding.
Although some cattle producers prefer to vaccinate during fall work for convenience; it makes the most sense from a BVDV control standpoint to vaccinate prior to breeding so that cattle have the best protection during early pregnancy.
