The symptoms of bovine viral diarrhea include fever, nasal discharge, ataxia and diarrhea, according to TheCattleSite. Pregnant cows may spontaneously abort or have stillborn calves, and calves born alive may have birth defects.
Live calves born to BVD-infected cows often have infections themselves, and they can remain contagious for their entire lives, notes TheCattleSite. Congenitally infected calves often have cerebellar hypoplasia, which results in an inability to move normally and an inability to nurse. These calves are more prone to pneumonia and other diseases. BVD can be fatal to calves.
Adult cattle can display many different symptoms, explains TheCattleSite. The animal may become lethargic and lose its appetite, and it may have discharge from its eyes. Nursing or dairy cows may have decreased milk production. Some animals develop mucosal disease, which results in ulcers in the mouth, muzzle and hooves, according to the Institute of Veterinary Virology at the University of Bern. Bloody diarrhea is also a symptom of mucosal disease.
Because animals persistently infected with BVD continue to shed the disease for the rest of their lives, owners generally cull them to prevent the spread of the disease, reports TheCattleSite. However, there are vaccinations available to help prevent infection.