home, farm, & garden by Sarah Southard, DVM
BVDV –
A SILENT LURKER
We’ve all done it – joined a group on a popular social media website and quietly observed all the shenanigans therein. We’ve all been “the lurker.” Depending on the group, we’ve even learned something useful while we’ve done it. Bovine viral diarrhea virus is a not-so-innocent lurker of sorts among cattle. Unaffected carrier animals are silently shedding millions of virus particles which are seeking out a vulnerable bovine in which to reproduce and wreak havoc. And in a naive herd, the havoc quickly becomes widespread and very costly. Bovine viral diarrhea (BVD) is a serious disease of cattle caused by the bovine viral diarrhea virus. It is widespread throughout the world and virtually all cattle are susceptible to disease. When the virus enters an unvaccinated or improperly vaccinated herd, a severe disease complex develops within a week, spreads through the herd and can be difficult to stop. Signs of infection include anorexia, high fever, bloody diarrhea, and pneumonia. Some animals will die quickly while others may recover within a couple of weeks. Recovered animals may have lasting damage to the gastrointestinal tract or lungs which leaves them unthrifty and poorly productive for the remainder of their lifetime. Cows which are infected and recover during pregnancy may lose the pregnancy or may give birth to a persistently infected calf that does not develop disease but carries and sheds the virus during its entire life. Proper herd vaccination and biosecurity protocols are the best ways to prevent a problem in your herd. Consult with your
veterinarian regarding which vaccines to give and at what time(s) during the year. Also develop a biosecurity plan for your herd regarding newly acquired animals. An isolation and quarantine period of one to two weeks should be sufficient to determine whether purchased animals are acutely infected with BVD. To determine whether new additions are persistently infected carriers, testing would need to be done prior to introduction into your herd. If a herd experiences an acute BVD outbreak, immediate treatment should be sought from the herd veterinarian. Also, a long-term control program will need to be implemented to test and cull any persistently infected animals from the farm. All calves born into the herd for a minimum of a year from the outbreak will need to be tested as soon as possible after birth to look for carrier status. Persistently infected carrier calves should be removed from the herd as soon as possible to prevent continued virus spread. Check and double-check your vaccine protocols to be certain that you are protecting your cow herd against BVD. Vaccination is by far the most cost-effective way to prevent a problem in your herd. Also be choosy about where you source animals from. Certain outlets are riskier regarding disease transmission than others. Quarantine all new additions prior to introduction to the herd. No cattleman wants to bury a portion of his calf crop or cow herd and then watch the remainder struggle to recover and remain unthrifty long-term. Take time to vaccinate and to isolate. “An ounce of prevention is worth a pound of cure!”
SURRY LIVING Oct. 2021 Issue • 15
