In a three-pronged approach to BVDV management, Dr. Chis Chase shares why bulk-milk testing can be an effective screening tool In large dairy herds, but not for smaller operations. In terms of biosecurity, Dr. Chase shares his recommendations for how to safely merge replacement heifers into your existing herd. You’ll also learn about BVDV vaccination timing — when is the best time for modified-live-virus vaccines and when should inactivated vaccines be used. Dr. Chase also shares new findings on the emergence of BVDV type 1b, and why your vaccine should include protection against this subtype. He’ll also discuss the role of the Singer strain of type 1a in vaccines and how it can provide additional protection against BVDV 1b. Your veterinarian can play a key role in developing an effective BVDV vaccination strategy, including how to help pregnant animals develop plenty of antibodies for the colostrum, to help new calves off to a strong start.

Cattle First Podcast

How to Protect Your Herd from BVDV

In our final episode, Dr. Chris Chase explains the pros and cons of killed and MLV vaccines. With MLV vaccines, he’ll explore the concepts of reversion to virulence, adventitious agents and maternal antibody interference.  He’ll also discuss the role of adjuvants in killed vaccines. You’ll learn the importance of boosting immunity with MLV vaccines before any animal is bred and how a killed vaccine during pregnancy can help develop high-quality colostrum for the calf. We’ll also explore the difference between vaccination and immunization and how to time vaccination to avoid a milk drop in lactating cows. Hear why Dr. Chase recommends involving your veterinarian in developing a vaccination protocol to help choose the right vaccines at the right time to boost herd health.

Killed vs. Modified-Live-Virus (MLV) Vaccine Choices

In this episode, we’ll learn how PI calves typically acquire the infection in the uterus, before their immune systems have fully developed. You’ll also hear why testing the pregnant animal or the amniotic fluid are not effective for identifying PI calves. Infected calves may be healthy and grow normally or can be poor-doers that don’t live much past a year of age. In either case, the calves are infected for life and will shed the virus in all body secretions, exposing other animals in the herd. If a PI animal escapes detection, it can result in significant costs down the road. Dr. Chase shares the results of a research study that followed a herd with PI animals, including how long it took PI animals to succumb to mucosal disease. Finally, how do you determine if a calf was infected in the uterus or whether it simply has antibodies to the virus from the colostrum of a vaccinated mother? Learn this and more in episode two.

The Impact of BVDV Persistently Infected (PI) Calves

Dr. Chris Chase is a Professor in the Department of Veterinary and Biomedical Sciences at South Dakota State University. His research has focused on developing better methods of detecting disease-causing organisms and preventing viral infections in animals. He has clinical experience in hog, dairy, cow-calf and feedlot herd health. In this episode, learn why testing every animal at birth is so important, well as why stillbirths, abortions and sudden deaths should also be tested. Dr. Chase discusses different testing methods, including polymerase chain reaction (PCR) tests using ear-notches or blood samples. He also covers when pooled laboratory samples may be appropriate. Dr. Chase recommends working with your veterinarian on a testing strategy to help minimize contaminated samples and the influence of recent vaccination that may impact test results. Finally, you’ll learn about transient BVDV infections, or infections that the animal’s immune system can clear it on its own, and when it might be worth a 30-day quarantine for animals that test positive.

Testing Strategies for BVDV

For cattle with bovine viral diarrhea virus (BVDV), diarrhea isn’t the main problem. Less obvious signs can presage economically significant reproductive and respiratory problems. What’s more, persistently infected (PI) calves shed the virus, placing the rest of the herd at risk. In this podcast, Successful Farming editor Bill Spiegel interviews Dr. Chris Chase, a veterinary immunologist at South Dakota State University, about proactive strategies for managing BVDV.

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Cattle First Podcast

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