Bovine viral diarrhea (BVD) is a disease that can cause reproductive losses, reduced performance, and suppression of the immune system. The most common route of transmission is exposure to persistently infected (PI) calves. A PI occurs when a fetus is infected with BVD between 30 and 125 days of gestation, the virus is not recognized as a pathogen and after birth the calf will shed large quantities of the virus for the rest of its life. Exposure can also occur from cattle that are temporarily infected or in rare cases from contamination of clothing or equipment.
