BVD is a serious disease of cattle in terms of economic cost, health and welfare, causing abortion, infertility, immunosuppression, failure to thrive and even death.
BVD causes a complex of diseases in cattle, the most important of which can interfere with reproduction, affect the unborn calf and lead to mucosal disease. BVD virus can also cause enteritis during acute or transient infection which is usually mild but occasionally severe enough to cause death, even in adult cattle. Transient BVD virus infection is associated with significant suppression of disease resistance and can contribute to outbreaks of pneumonia or scours in calves, and other diseases.
The disease is mainly spread by persistently infected, or PI, cattle. These are born with the disease, having come into contact with the virus in the womb during the first 120 days of gestation. They will have BVD all their lives and they shed virus extensively, infecting naive cattle directly and indirectly. Most die as calves but a few live much longer. Identifying and removing them from the national herd is critical to any eradication attempt.
The principle BVD order is The Bovine Viral Diarrhoea (Scotland) Order 2019 which sets out the main requirements of the BVD eradication scheme in Scotland.