TEST FOR AND CONTROL BVD > FACT-SHEET
BVD IN NEW ZEALAND
BVD is widespread
- 95% of dairy herds show evidence of past exposure (BVD antibody detectable in bulk tank milk)
- At of 2015, approx. 60% of dairy herds were “actively infected” (s:p >0.75)
Contact with PI animals is the source of active BVD infection. So, BVD control requires two phases:
- Find and eliminate PIs
- Monitoring
- Culling PIs
- Prevent new PIs from being created
- Biosecurity
- Vaccination
MONITORING
BVD antibody testing
- Blood or milk samples from >9 animals
- Indicates herd’s level of past exposure to PIs
- Higher group antibody = more recent & widespread PI exposure
- S:P > 0.75 means there may be a PI in contact with the herd now: “active” BVD infection
BVD virus testing
- Blood, milk or body tissue (ex: ear notch) from one or more animals
- A positive test means an animal which has been tested is either a PI or is transiently infected
- Isolate and retest positive animals (or cull them straight away)
- Cull all confirmed PIs ASAP — they will always be a source of BVD infection!
- Get vet involved to find PIs or possible sources of PI contact
BEST PRACTICE MONITORING & CULLING PROGRAM FOR DAIRY FARMS:
- Bulk milk testing
- Antibody (s:p): 2-3 times per year
- Virus test (PCR): necessary if bulk milk antibody is >0.75, or has gone up significantly since last test. Recommended 1-2 times per year, before mating, when all cows are contributing to the vat
- Get vet involved: if you need to find a PI or a source of PI contact, they will be able to help!
- Calf & purchased/leased animal testing
- Virus test (PCR or Antigen ELISA) blood samples or ear notches
- Cull/reject any PI animals you find
- This checks how well your biosecurity and vaccination programs are working
- Service bulls
- Virus test (PCR or Antigen ELISA) blood samples or ear notches
- Vaccinate (sensitiser & booster) 1 month before mating
Additional biosecurity & vaccination measures are necessary if your animals are ever at risk of PI contact.
REFERENCES
- Weir, A. (2016). Epidemiology of BVD in New Zealand dairy herds. Massey University PhD thesis dissertation.
- Hill, F et al. (2010). Testing of pooled sera to predict the BVDv infection status of cattle. VetScript. 05/2010: 38-39.
- MC Gates, CA Evans, C Heuer, H Voges & JF Weston (2021) Temporal trends in bulk tank milk antibody ELISA and PCR test results for bovine viral diarrhoea in New Zealand pastoral dairy herds, New Zealand Veterinary Journal, 69:2, 73-82.
FOR MORE:
Visit https://www.bovilis.co.nz/bovilis-bvd/
Or find us on YouTube by searching: TopFarmersNZ
Or visit: msd-animal-health.co.nz
Top Farmers Know-How provides a reference library of industry best practice in some key animal health management areas including mastitis, dry off, calf health, BVD, salmonella and campylobacter. We know that farmers and vets are busy people, so we’ve created resources in different formats and in bite-sized chunks to make it more flexible and accessible.