Bovine Viral Diarrhoea (BVD) in Cattle

Bovine viral diarrhoea (BVD) is a costly infectious disease for the dairy industry. Advances in the knowledge of disease transmission and the introduction of effective vaccines have enabled the control and eradication of the BVD virus from infected herds.

Infection with BVDV can have different clicinal manifestions depending on the herd’s immune and reproductive status. Infertility or abortion diarrhoea, mucosal disease and respiratory signs are common clinical signs and can be seen simultaneously in a herd.

Etiology of BVD

The causative agent of BVD is bovine virus diarrhoea virus (BVDV). Two genotypes have been identified:

• BVDV-1, distributed worldwide
• BVDV-2, identified mainly in North America and occasionally in Europe.

The BVD virus exists as two different biotypes: the noncytopathic (ncp) and the cytopathic (cp) biotypes. Only the ncp biotype can cause persistent infection of the bovine fetus. Calves persistently infected with an ncp BVD virus will develop mucosal disease if the virus mutates spontaneously into the cp biotype or the calf is infected with a cp virus closely related to its own ncp BVDV strain.

Control of BVD

• Vaccination against BVD - The main emphasis of vaccination is to prevent the birth of persistently infected calves. Therefore, only vaccines that have demonstrated efficacy in terms of fetal protection should be used.
• Diagnostics - Apart from vaccines, diagnostic tests are important tools in BVD control. Laboratory tests both for virus- and antibody testing in serum and (bulk) milk samples have been developed and improved over the past years.
• Eradication schemes - BVD eradication programs on national or regional level are in progress or in preparation in a number of European countries.