In the September 2009 BEEF article “Gunning for a New Old BVDV Strain,” on page 38, author Wes Ishmael writes, “…there are no commercially available vaccines today that contain BVDV 1b.”
We received an informed call questioning that statement and asserting that three commercial vaccines contain sub-genotype 1b. Besides wanting to ensure the accuracy of the article and respecting the opinion of the caller, we dug a little deeper.
With the help of veterinarians, best as we can tell, there are no labels that specify BVDV 1b, Modified Live Virus (MLV) or killed. We've no doubt a strain may be present or that cross-reactivity to it may be observed in the vaccines mentioned to us. But, we don't find it on the labels.
Secondly, we were directed to a study published in 2002, authored in part by recognized BVDV experts Chris Fulton and Julia Ridpath — “Bovine viral diarrhea virus (BVDV) 1b: predominant BVDV subtype in calves with respiratory disease.” According to the study, “The BVDV1b subtype has considerable implications, as, with one exception, all vaccines licensed in the United States contain BVDV1a, a strain with different antigenic properties. BVDV1b potentially could infect BVDV1a-vaccinated calves.” The vaccines we received the call about were approved prior to this study.
The bottom line of the article remains the same. Antigenic cartography is helping some veterinarians build an autogenous vaccine that does contain 1b. Using this vaccine alongside a commercial MLV 4-way vaccine that accounts for BVDV genotypes 1a and 2a, these veterinarians have reduced feedyard morbidity by up to 50%, compared to only using the MLV 4-way.
Find more letters from fellow readers at the BEEF mailbag, www.beefmagazine.com.