BVD Testing
Bovine Viral Diarrhea (BVD)
BVDV is a common cause of respiratory and reproductive issues and is a key component in the bovine respiratory disease complex. Direct and indirect costs to BVDV infection in a herd can include loss of cows and calves, loss in meat and milk, additional labor wages and medications, reproductive inefficiencies, and immunosuppression. Cattle of all ages are susceptible to BVDV infection. Animals can have an acute or persistent infection. Animals that test positive for BVDV can be retested in three weeks to differentiate between the two types. Despite the name, this virus does not always involve diarrhea.
- Acute infection: Also known as transient infection, occurs when any animal encounters the virus via infected herd mates or contaminated items. Symptoms can include fever, lethargy, respiratory infections, and more. However, most infections are subclinical, meaning there are no outward signs of disease.
- Persistent infection (PI): This occurs when a pregnant animal encounters the virus via infected herd mates or contaminated items. Exposure at 60-120 DCC can lead to the calf never recognizing the virus as an invader. If this calf survives to term, it will be infected for its entire life and will constantly shed the virus to herd mates. No animal can become a PI after birth.
- Milk
- Individual (fresh, frozen, or preserved)
- Bulk tank (fresh or preserved)
- How to collect a milk sample
- Serum (fresh)
- Tissue (fresh or frozen ear notch)
WHEN TO USE
- Test at any age or stage
Testing Strategies
- Bulk tank screenings: Monitor milking herd status. Can detect the virus in groups up to 240. Consult technical specialist for herds greater than 240 cows.
- DHI milk samples: Ideal for testing groups or whole herd of milking cows when a PI is suspected in the milking herd. Samples can be tested individually or pooled in the lab to reduce costs. Minimum of 20 samples are required for pooling strategy. Positive pools are broken down to identify positive individual(s).
- Individual serum samples: Use to detect and confirm persistently infected animals.
- Ear notches: Ideal for testing calves at any age. Samples can be tested individually or pooled in the lab to reduce costs. Minimum of 10 samples are required for pooling strategy. Positive pools are broken down to identify positive individual(s).
Result interpretation
Reported as Positive, Negative
ELISA
BVD virus antigen was detected, which could indicate acute or persistent infection.
No BVD virus antigen was detected
PCR
BVD virus was detected, which could indicate acute or persistent infection.
No BVD virus was detected
How do you determine persistent vs acute infection
Retest three weeks later. If the second result is negative, that is indicative of acute infection. If the second result is positive, that is indicative of persistent infection.
| Test Type | Positive | Negative |
|---|---|---|
| Milk & Blood ELISA | >0.15 | <0.15 |
| Ear Notch ELISA | >0.30 | <0.30 |
| Milk, Blood, Ear Notch PCR | <38 | Undetected |
Testing Supplies
- Shippers and sampling supplies available to purchase online
- Ear notcher to collect tissue samples
FAQs
What is Bovine Viral Diarrhea (BVD) and how does it affect cattle?
What’s the difference between acute and persistent BVD infection?
Acute infection (transient): Can occur when any cattle are exposed to the virus. Signs can include fever, lethargy, or respiratory illness, though many cases show no symptoms.
Persistent infection (PI): Happens when a cow is infected during pregnancy (60–120 days of gestation). The calf becomes infected for life and sheds the virus continuously, spreading BVD throughout the herd. No animal can become PI after birth.
When should you test cattle for BVD and what samples are used?
How are BVD test results interpreted?
- ELISA Positive: BVD antigen detected
- Could be acute or persistent infection. Retest in 3 weeks to confirm.
- ELISA Negative: No BVD antigen detected
- Retest annually
- PCR Positive: Virus detected
- Retest in 3 weeks to determine if the infection is persistent.
- PCR Negative: No virus detected
- Retest annually.
If both the initial and follow-up tests are positive, the animal is likely persistently infected (PI). In this case, the dam should be tested as well.
Where can I send samples for BVD testing?
BVD testing can be submitted directly to the CentralStar laboratory. Milk samples can be fresh, frozen, or preserved. Tissue samples can be fresh or frozen. Serum samples should be fresh only. Testing supplies and ear notch collection tools are available for purchase online.
CentralStar’s laboratories provide sample analyses on milk, blood, fecal, and tissue samples for a variety of production, disease and health-related traits. More than 6 million samples are processed annually using state-of-the-art equipment and techniques including infrared spectroscopy, flow cytometry, ELISA, PCR, and more.
CentralStar laboratory services are intended solely for the detection of specific microorganisms or viruses in approved sample types. These services do not evaluate, certify, or guarantee the safety of milk for human consumption. It is recommended that interpretation of the results provided, and management decisions based on these results be done under the advisement of a veterinarian.