BVD & LIC Results

Bulk Milk testing

LIC offers a Bovine Viral Diarrhoea (BVD) bulk milk test as part of your regular herd test.  This test will measure two aspects of your bulk milk sample in relation to this disease.

SP Ratio

The first is the SP ratio which looks at antibody levels.

This is the paintball splat with a letter appearing on the graph in the middle.  If the levels are high, it means the cows have been exposed to BVD and are actively producing antibodies. If low, they are less likely to have been exposed and hence antibody is not being actively produced. If the levels are somewhere in between, it may mean that in the past, the herd was exposed, but the antibody levels are declining, or a BVD-free herd may have been recently exposed, and therefore the antibody levels are increasing.

BVD Antigen

The second thing measured is the presence or absence of the virus (different from the antibodies produced in response to exposure to the virus).

This is represented by the arrow at the top of the graph. If you get the red arrow, it tells us that one of the cows that contributed to the vat on the day they were tested is a carrier. If you get a clear arrow, then there are no carrier cows amongst the cows that contributed milk to the vat that day.  Remember that is not to say there isn’t a carrier cow in the penicillin mob or the younger stock.

Low Antibodies

In general, a low antibody level (yellow or orange splatter) tells us that your herd has a low level of exposure to BVD.

That’s fine if your herd is biosecure, but you are at risk of a more severe outbreak if it is introduced. A high antibody level tells us your herd has a high level of exposure and is likely to have been exposed recently to BVD, usually meaning that there is a carrier lurking somewhere in your herd.

There is no one size fits all solution to BVD. The best thing to do is, armed with your most recent LIC splatter and arrow graph, accost your friendly vet next time he/she is on the farm to work out what would best work for you.

Warkworth Veterinary Services Ltd

We are a seven vet mixed practice, serving the greater Warkworth and Wellsford regions, from Puhoi in the south to Maungaturoto in the north and from east to west coast in between.