The test is accurate even for calves soon after birth, allowing earlier detection of persistently infected animals. We're finding a few positives.
Symptoms range from mild to severe diarrhea.
BVD also suppresses the immune system, which can lead to other bacterial and viral infections. Persistently infected animals aren't common but can be difficult to detect, and a single case can be devastating. The BVD virus spreads from animal to animal in a herd. When a pregnant cow becomes infected at between 80 and 150 days gestation, the virus passes to the fetus. The fetus's immune system isn't developed enough to recognize the virus as an infection.