Ear-notching calves to test and identify ones that are persistently infected with BVD is an important step that all producers should follow, says Julia Ridpath, microbiologist in the USDA Virus and Prion Diseases of Livestock Research Unit, in Ames, Iowa. However, it can get expensive to test each calf.

One alternative, says Ridpath, is to ask the diagnostic lab to perform a combined ear-notch test.  In a combined test, the lab places the extracts from each ear-notch sample into one test. (Depending on the lab, group size for testing will range from 10 to 100 samples.) If the group test comes back positive, the lab then tests each individual sample. But if the group test comes back negative, you have just cleared that many calves for the cost of one test.

In addition, always use a reputable lab with a proven track record. Don’t be afraid to ask for references, she adds.