Bovine Viral Diarrhea continues to cause significant concern to cattle producers’ nation wide. Bovine virus diarrhea virus (BVDV) persistently infected (PI) animals are the main source of spreading BVDV. Allowing a PI animal to remain in a herd with other animals of breeding age perpetuates the virus by producing additional PI animals in the herd. Therefore, continual testing in conjunction with adopting adequate biosecurity measures and vaccination procedures is the way to eliminate BVD from a herd.  Testing protocols vary but often begin with the testing of the entire calf crop followed by testing any dams from positive calves and cows not represented by the testing of the calf crop.

It has been observed that the BVDV antigen-capture ELISA, currently used for testing BVDV PI animals, may yield occasional false positive results when testing serum samples, and test specificity may be higher on ear notch samples. Because of the lower specificity of serum, animals testing positive on serum should be confirmed by ear notch ELISA or by whole blood virus isolation.  Alternately, the initial submission of ear notch samples may avoid the need for resubmissions.  We now recommend EAR NOTCH AS THE SAMPLE OF CHOICE for testing BVDV PI animals.  

When submitting the ear notch:

1. Collect an ear notch approximately 1 cm x 1 cm (3/8 in x 3/8 in) in size.  Only fresh ear notch samples are acceptable for the antigen-capture ELISA assay. The ear should not be cleaned with anything but water.  Disinfectant of any kind (e.g. Novasan) can interfere with the test.

2. Place the fresh ear notch in a sterile clean Vacutainer red top serum test tube (no residue of detergent, bleach or material for separation of serum)

3. Number (or pre-number) the tubes using consecutive numbers (1, 2, 3, etc) and keep a list of the corresponding animal ID or tattoo numbers.  This method of labeling significantly reduces the turn around time in the laboratory and gets the results to you faster.

4. Notify the laboratory in advance prior to shipment regarding the number of samples and when they will be sent. This allows us to have adequate supplies for testing and to arrange staffing to do the testing.

5. Send samples to the laboratory with sufficient ice packs to chill the specimen during shipment. Saline or other media must NOT be added to the tube containing the ear notch.  Likewise, please DO NOT use any fixative (e. g. formalin).

Dr. Ed McKinley, Pathologist, Assistant Director, C.E. Kord Animal Disease Diagnostic Laboratory