How To Systematically Manage BVDV
Your focus needs to be on PI animals!
PI animals are born from other PI’s (approximately 10%) or from animals which were transiently infected with BVD (approximately 90%).
PI animals propogate transient infections in other animals. However, unlike other diseases, transient infections normally do not propagate the disease. Prior exposure or vaccination to BVD prior to being exposed to a PI provides a level of protection to the individual animal and herd.
The goals of systemic BVD control are straightforward:
Identify at risk management groups and provide them with immunity
Ensure annually that each new replacement heifer management group is both PI free and reasonably immune prior to their first joining
Ensure no adult PI animals exist within any of the pre-existing adult management groups
Maintain simple biosecurity procedures
There are 3 tools for managing BVD
Blood Testing (Antibody) Exposure Test
The IDEXX BVDV Total Ab Test is an enzyme immunoassay (ELISA) designed to detect BVD antibodies in serum, plasma and milk samples. A positive test result indicates prior exposure (or vaccination) to BVD.
Bulk milk screening
An easy, non-invasive, cost effective way to monitor BVD management efforts. It can be an early indicator of a problem before clinical signs or symptoms can be seen.
Ear Notch Testing (Antigen) Finding the PI
Ear Notch testing using the IDEXX BVDV Ag Serum Plus test is the easiest and most widely used test globally to reliably detect PI animals.
Individual PCR testing
The most sensitive and specific method of identifying BVD infection. However, it does not differentiate between transient and persistently infected animals. A PCR positive animal should be quarantined and re-tested 2 weeks later. In order to identify only PI’s the superior test is the IDEXX Antigen ELISA.