Bovine viral diarrhoea Virus is the most prevalent infectious disease of cattle worldwide.
In New Zealand cattle farmers lose more than $150 million per year through the negative effects of BVD these include:
BVD infection during pregnancy can result in the production of a persistently infected (PI) foetus. Whilst many farmers recognize the cost of culling a persistently infected (PI) calf the greatest economic cost of BVD is the impact on herd performance. Click here to find out more about persistently infected calves and how they are created.
Whilst BVDV can cause devastating effects on farms that have not had BVDV exposure, due to the widespread nature of BVDV, most producers will see no overt clinical signs of BVDV.
BVDV is a silent killer
3 Types of Infection
1. Acute (transient)
Exposure to the virus normally results in a transient infection (the cow will get better)
2. Foetal Infection:
If a cow is exposed whilst pregnant, abortions, still births and reduced fertility are likely (Reichel et al., 2018).
3. Persistent Infection (PI):
When foetal infections occur before the development of immunocompetence, persistently infected (PI) cattle are born. PI animals shed high levels of virus (Reichel et al., 2018).
The Impact of BVD infection during pregnancy
Approximate timing of infection
0 - 40 days
Early embryo loss
40 - 120 days
Persistently infected calf
How does BVD Spread?
Persistently infected (PI) animals shed large quantities of virus and therefore are the single most important source of infection on farm BVDV is almost exclusively spread by direct contact with PI cattle (Development, 2019).
All BVDV control efforts need to focus on the identification and elimination of PI animals.