Mixing of selenium and anthelmintic drench

Extract

Bovine viral diarrhoea (BVD) virus has a worldwide distribution and investigations in various parts of the world have shown that 60%–80% of cattle have neutralising antibodies to the virus⁽¹⁾⁽²⁾. Bovine viral diarrhoea virus infection is also common in New Zealand dairy herds⁽³⁾, and its epidemiology on dairy farms is well understood. It had been considered that the traditional beef cattle population was essentially free from this infection and there was a concern that the rapidly expanding dairy-beef industry may introduce infection into an essentially naive beef cattle population. However, a recent study has shown that BVD virus infection is widespread in beef herds throughout New Zealand⁽⁴⁾. To explore the issue further, we have examined the prevalence of BVD virus antibody- positive animals in selected dairy-beef operations and traditional cow-calf herds, and how BVD-virus infection, if present, is maintained within these cattle populations.