Before you test individual cows and calves to see if bovine viral diarrhea virus is present in the herd, consider conducting a bulk-tank test.

A 200-milliliter bulk tank sample in herds of 150 cows or less can be used to detect BVD, explains Don Gardner, veterinarian in Huddleston, Va. The test is called a polymerase chain reaction test and can be conducted at the diagnostic labs at Colorado State University and Cornell University. The cost is $50.

If the sample tests positive for BVD, then testing of individual animals is warranted. In larger herds, string samples can be collected from individual groups as long as the groups have 150 cows or less. (Cornell just recently announced it can now test a sample from groups up to 400 head with the PCR test.)