Bovive Viral Diarrhoea (BVD)

 
 

What is Bovine Viral Diarrhoea (BVD)?

BVD is a viral disease that causes substantial losses on dairy and beef units due to reduced fertility. There are several effective licensed vaccines available in the UK which can be used for herd protection. However, it is important to remember that vaccines rarely offer the herd 100% protection so surveillance programs should be discussed with your farm vet to ensure that farm status is not compromised. Host response can be detected at the herd level by testing for antibodies in cohorts (either bulk milk for dairy or a cohort of calves’ bloods).    

Transmission

BVD can exist on the farm as latent infection which can cause mild symptoms and temporarily reduced fertility in healthy animals. Most animals are able to produce antibodies against BVD (these are termed competent animals) and thus are able to counteract the infection.  However, if a pregnant dam becomes infected in the first 120 days of gestation, her calf will be born persistently infected (PI). PI calves are a source for active infection on the farm, shedding vast quantities of virus throughout their life.  They will never produce antibodies and thus will not rid themselves of the infection even when vaccinated. PI calves remain a source of infection and thus a risk for the herd for their entire life. If a PI heifer makes it to sexual maturity, she will always have a PI calf.    

Symptoms

  • Condition loss
  • Occasional diarrhoea
  • Widespread infertility
  • abortion
  • stillborn calves
  • early death in calves
  • malformed calves
  • calf blindness
  • Mucosal disease and sometimes death in adolescent animals

It is important to discuss testing with your farm vet to ensure that the most cost effective method is selected. 

Prevention and management

Prevention of BVD can involve:

  • General surveillance of Bulk Milks (dairy) and youngstock (beef and dairy)
  • Vaccination
  • Tag and testing dead or dying calves
  • Increased biosecurity between youngstock and adult groups
  • Double fencing boundaries between cattle farms
  • Safe disposal of aborted/stillborn calves

Options should always be discussed with the farm vet. 

NML Testing Services

  • Bulk milk antibody ELISA (for dairy herds)
  • Individual milk antibody ELISA
  • Individual cow blood antibody ELISA
  • Individual cow blood antigen ELISA (tests for virus)
  • Individual tag and test tissue antigen ELISA (tests for virus)

Individual Milk tests can be performed on one milk sample through to a whole herd test. NMR recording customers can request individual cow tests on their normal milk recording samples taking the hassle out of testing. For non-NMR recorded herds we will send kits enabling you to take the required number of samples and submit them to the laboratory for testing.

Bulk Milk surveillance (Step 1 taken from BVD monitor)

Our Bulk Milk antibody test can be affected by the vaccine so it is important that vaccinated herds monitor antibody levels quarterly to ensure the trend is level or falling. Unexplained sharp rises should prompt further investigation. To find out more on suggested steps to BVD control please click here.

Bulk milk tests for BVD can be done on an ad-hoc or quarterly basis. The bulk samples can be tested on samples held in the NML fridge or by requesting a bulk milk sample kit.

Tag and Test

Whilst tag and test is primarily recommended for PI identification, it can be used for surveillance in some circumstances. If a new herd is being established or a block-calving system is being used, a season’s calves can be tag and tested. The dams of any calves which have tested negative for virus (non PI) can be deemed as being a non PI.  Furthermore, grand dams of non PIs can be deemed as being non PI. It is important to remember that these assumptions are only applicable where the correct dam is known and proven for her respective calf.  

It is important to discuss testing with your farm vet to ensure that the most cost effective method is selected. 

Click here to find out more information on Tag & Test

Ordering

To order Individual milk tests for BVD simply ask your NMR milk sampler to fill out a blue form to be included in with you recording samples. For Non NMR herds please call customer services to request sampling pots on  042 96 75 353 or email enquiries@imlabs.ie.

To order a BVD bulk milk test please call the NML office along with your Milk Buyer ID on  042 96 75 353 or email enquiries@imlabs.ie

To order a blood test just ask your vet to take a blood sample and submit it to the NML laboratories.

Results

Results are available through normal notification methods. These include post, fax or email.

 

Quicklinks

For ad hoc SCC or constituent testing contact IML