Currently, the most cost effective and sensitive strategy for BVDV persistent infection testing at the ISU VDL is immunohistochemistry on formalin-fixed ear notch samples.
In certain situations, pooled PCR testing of fresh ear notch samples can be a cost effective way to screen groups of calves. Recent vaccination or a current acute BVDV infection in the group can result in positive PCR results. As long as samples arrive in good condition, IHC testing on any PCR positive pool can be used to identify persistently infected calves within that pool.
Materials and Equipment Needed:
1. An ear notching tool that yields a 1cm a side notch, these are available from sources listed below, as well as others.
• Nasco: 800-558-9595, Order ID medium C0024N
• Dairy Health USA: 800-276-7933, Order ID medium 440-31
• Stone Livestock Identification, Show Equipment:
816-231-4020 Order ID medium 7125
2. Snap–cap milk tubes [please do not use whirl-pac bags].
3. Shipping container rack that organizes individual tubes in slots.
4. Submission form: Use the Ruminant Health Test Request form found here.
5. Vaccination and tattoo ink do not affect immunohistochemistry techniques, when done at the same time samples, are taken. Recent vaccination may result in positive PCR testing or fresh ear notches.
Collection Procedure for IHC testing (formalin fixed ear notches):
- Label collection tubes with the animal ID’s and sequence number’s (#1 through number in submission).
- Dip notching tool in disinfectant, then rinse. Residual disinfectant does not affect immunohistochemical techniques.
- Take a proper size ear notch from a clean portion of the ear (Figure 1).
- Place notch into a labeled, collection tube with enough 10% buffered neutral formalin to cover the notch. Ensure that the ear notch is submerged in formalin during shipping.
- Ear notches can be stored for up 1 week prior to shipping. Refrigeration once formalin-fixed is not required.
Figure 1: Best location for taking ear notch
Collection Procedure for PCR testing (fresh ear notches):
- Label collection tubes with the individual animal ID’s and sequence number’s (#1 through number in submission).
- Dip notching tool in disinfectant, then rinse well (clean well between each calf).
- Take a proper size ear notch from a clean portion of the ear (Figure 1).
- Place notch into a labeled, empty, dry collection tube.
- Chill/refrigerate as soon as possible; DO NOT FREEZE samples. Ship to the lab immediately.
- Ear notches can be pooled as desired, up to 25 per pool.
- PCR positive pools can be tested via IHC to identify any potential persistently infected calves: fresh ear notches are placed in formalin at the lab after samples have been tested via PCR, in case IHC testing is required.
Submitting Samples
Contact Information
Feel free to contact Dr. Drew Magstadt at 515-294-1950 or any of the diagnostic pathologists at ISU VDL with any questions regarding BVDV surveillance and sample collection, or to discuss the various testing options available.