Livestock Workshops: eradication of disease

This workshop provided a brief overview of bovine viral diarrhoea (BVD) and sheep scab, with a focus on how the Gwaredu BVD and Gwaredu Scab programmes have helped on the path to disease eradication and how veterinarians can use the ideas developed in these schemes in their own practice.

BVD virus is in the Flaviviridae family. There are two genotypes, BVD 1 and 2. BVD 1 occurs in the UK, and there are two biotypes: cytopathic and non-cytopathic. Most persistently infected calves have non-cytopathic BVD at the point of diagnosis. Cytopathic virus causes mucosal disease. BVD is an immunosuppressive disease of cattle that causes increased pneumonia, diarrhoea and abortions, and increased disease overall. There is also an increase in greenhouse gas emissions in comparison to uninfected populations. BVD causes a persistent and long-term drag on productivity.

The most important agent of spread is the persistently infected calf. Persistently infected calves are born infected – BVD virus infects the calf in utero (at 40–120 days gestation) and is viewed by the immune system as part of the calf and therefore these calves never have an immune response and they spread virus in large amounts for the rest of their lives.