Specimen: 10 mL serum, 50 mL milk
Container: Red top or gel tube, sterile 50 mL pottle
Collection protocol: Serum -venepuncture; Milk – collect from a well stirred vat one hour after milking finishes. Alternatively, arrange collection from the milk processing company. Contact your local Gribbles Veterinary laboratory for details
Special handling/shipping requirements: Standard, keep chilled
General information about the disease:
Bovine viral diarrhoea virus (“pestivirus”) is one of the most significant viral diseases in cattle. Clinically, there are three forms of the disease:
- A persistently infected (PI) form which may/may not have clinical signs
- An acute transient form characterised by fever and diarrhoea and short term immunosuppression. These animals will mount an immune response and clear the virus in 10-14 days.
- Mucosal disease (MD) only occurring in PI animals. PI animals are infected by a noncytopathogenic strain of the virus. A subsequent spontaneous mutation of the virus to a cytopathogenic strain within the PI animal results in MD, characterised by seromucoid nasal secretions, severe erosive lesions in the oral and intestinal mucosa, diarrhoea and death.
General information about when this test is indicated:
- Recommended for cattle older than 10-months-of-age once all colostral immunity has waned. It may also be used in pre-suckling calves to determine whether exposure occurred during late gestation.
- Once infected, cattle will be viraemic for 10-14 days. About 2-4 weeks after infection is cleared, antibodies to BVD will be produced and can be detected.
- Detecting BVD antibody in the fetus indicates there has been viraemia of both the dam and fetus after 150 days gestation, when the fetus is immuno-competent and antibody has been formed. However antibody positive fetuses have not necessarily died because of BVD infection. Nevertheless, detecting antibody is significant as it shows there was virus circulating in the herd.
- Pooled antibody testing is possible using bulk tank milk or 9-15 pooled sera from non-lactating animals.
- Pooled results are reported as a numerical S/P value. This is the sample value divided by the positive control. The S/P value can be compared with epidemiologically derived values to predict the likelihood of virus infection in the group.
- Individual ELISA values are reported as positive or negative.
- For surveillance, annual testing is recommended of either pooled serum samples from 15 yearling animals and/or a bulk milk antibody test on the lactating animals.
Comparison with other related tests: Used in conjunction with PCR and antigen ELISA testing
BVDv testing summary:
BVD tests to use in calves from conception to 10 months of age. (NOTE: ear notch samples cannot be used for antibody ELISA*)
|Age||PCR||Antigen ELISA||Antibody ELISA||Sample|
|40-120 days gestation||Y||x||x||Foetal fluid|
|150 days – birth||Y||x||x||Foetal fluid|
|Birth-35 days||Y||(ear notch only)||x||Serum|
|35 days -10 months||Y||Y||x||Serum/skin|
|10 months and older||Y||Y||Y*||Serum/skin|
Individual tests for BVD depending on disease or physiological state
|Disease or physiological state||PCR||Antigen ELISA||Antibody ELISA||Sample|
|Transient infection (TI)||Y||Y||Y||Serum/skin*|
|Persistent infection (PI)||Y||Y||Y||Serum/skin*|
Group test options
|Physiological state||PCR||Antigen ELISA||Antibody ELISA||Sample|
|Non milking||Y||x||Y||Pooled serum|
x = No, Y= Yes