Bovine viral diarrhea (BVD) is a common viral disease that affects cows worldwide. It is caused by the bovine viral diarrhea virus (BVDV) and can cause a range of clinical signs in infected cows, including fever, diarrhea, respiratory issues, decreased milk production, and reproductive problems. BVD is primarily spread through contact with infected animals, such as through nasal secretions, saliva, feces, and milk. It can also be spread through contaminated equipment or facilities. There are two types of BVDV: non-cytopathic and cytopathic. Non-cytopathic BVDV is the most common type and typically causes mild or subclinical infections. However, cows that are infected with non-cytopathic BVDV can become persistently infected (PI) and shed the virus throughout their lives, serving as a source of infection for other cows. Cytopathic BVDV is less common but can cause severe clinical signs, including hemorrhagic syndrome and death. Preventing the spread of BVD in cows involves implementing biosecurity measures, such as testing new animals before introducing them to the herd, isolating and treating infected animals, and properly cleaning and disinfecting equipment and facilities. Vaccines are also available to help prevent BVD, but their effectiveness can vary depending on the type of vaccine and the strain of BVDV present in a given area. BVD can have a significant impact on the health and productivity of cow herds. In addition to the clinical signs mentioned earlier, BVD can also cause immunosuppression, making cows more susceptible to other infections. It can also cause reproductive issues, such as infertility, abortion, and congenital defects in newborn calves. It is important to note that BVD can affect cows of all ages, but pregnant cows and young calves are especially vulnerable. Pregnant cows that become infected with BVDV during the first trimester of pregnancy may give birth to calves that are persistently infected with the virus, which can be a significant source of infection in the herd. Calves that are born with congenital defects due to BVDV infection may also have a reduced chance of survival or face long-term health issues. Diagnosis of BVD in cows typically involves laboratory testing of blood or tissue samples to detect the presence of BVDV or antibodies against the virus. Once a diagnosis is made, treatment options for BVD are limited, and management strategies typically focus on preventing the spread of the virus and providing supportive care for affected animals. Overall, prevention is the best approach to managing BVD in cow herds. This involves implementing biosecurity measures, using appropriate vaccines, and maintaining a healthy and well-managed environment for the cows. Working closely with a veterinarian can help ensure that the appropriate prevention and management strategies are in place for a specific herd.