BVD Testing
What’s a BVD PI?
Bovine Viral Diarrhea Virus – Persistent Infection.
A fetus which becomes infected with certain strains of BVD virus between 60-125 days in gestation will tolerate the virus as part of itself and subsequently be born with extremely high levels of virus throughout its body and shedding the BVD virus to herd mates.
Why are BVD PI's a problem?
PI calves can cause infection and immunosuppression of herd mates resulting in reduced conception rates and increased abortions in cows. It may also result in increased pneumonia and other diseases in calves, increasing mortality rates.
How to collect BVD samples:
- Take a 1/2 - 1 cm ear notch with a clean ear notcher.
- Place the ear notch in a sterile milk tube.
- Rinse the ear notcher betweeen calves.
- Record animal ID on the sample tube.
- Refrigerate for 1-3 days or freeze.
- Deliver or ship to Ag Health Labs.
Who should be tested?
- High risk calves from unknown origins or vaccination histories.
- Calves from purchased replacements (who were pregnant when purchased)
- The dam of any BVD PI positive calf.
- Breeding bulls. All initial Breeding Soundness Exams should include a BVD PI Test.
- Dairy Calves. Especially if co-mingled at a heifer grower or calf ranch.
Costs of a PI in your herd:
Cow-calf herd - $14-25 per cow exposed. (Larson, et al, 2002)
Feedlot - $41-93 per cow exposed. (Dr. Dan Grooms, MSU, 2016)
Dairy - $45-55 per dairy cow exposed. (Dr. Derrell Peel, OSU, 2016)
What tests are we running and why?
Pooled PCR – PCR is extremely sensitive and can detect a PI animal out of a pool of up to 24 animals. Pooling samples makes PCR the most cost effective test method. It may also detect transient BVD infections.
ELISA – ELISA is a confirmatory test on individuals in a positive pool. It is highly specific for Persistent Infections.