BVD: Why Biotype MattersWhen veterinarians discussbovine viral diarrhea (BVD) viruswith producers, they often talkabout the two different genotypes– BVD Type 1 and BVD Type 2. Thetwo BVD biotypes – noncytopathic(NCP) and cytopathic (CP) – areseldom mentioned. Yet, the NCPbiotype causes greater than 90 percentof BVD outbreaks.“According to research, NCPBVD is always the cause of persistentlyinfected (PI) animals,” saysGary Bosch, DVM, director of researchand development at NovartisAnimal Health US, Inc. “NCP isnot something that we can ignore.”If there is a PI animal in the herd,it is constantly shedding the BVDvirus and exposing the herd to diseaseevery day. The animals’ immunesystems are constantly beingprimed to fight off disease, resultingin reduced performance. Theremay not be clinical signs of infection,but economic loss is likely inthe form of a variety of illnesses.BVD viruses fall into two differentgenotypes known as BVD Type1 and BVD Type 2. Viral strains arealso classified by biotype accordingto behavior in cell culture. Astrain is cytopathic (CP) if it killscells in tissue culture or NCP if itdoes not kill cells.“The main difference betweenthe two biotypes is that CP infectscells in the gut lymphoid tissues,”explains Bosch, “while NCP infectsa wider range of cells, including therespiratory tract, blood cells andlymphoid tissue. NCP also persistslonger in the animal.”Producers can eliminate PIcalves, the main source of BVD infection,by:• Screening to detect PIs• Culling positive animals• Quarantining new animals untilthey are determined PI-negativeAffordable <strong>Feedlot</strong>SoftwarePrograms Include:Pro Feeder VIICattle On FeedPro Mini VIIPro Med IIPro Private VRisk ManagerPro Pasture VAge Verification ProgramOption to interface with Quick Books ProOption to interface with other drug and bunk programsAffordable technical support and maintenancePROGRAMS CAN BE INSTALLED ON NETWORKS orMULTIPLE COMPUTERS AT NO ADDITIONAL COST!HI-PLAINS SYSTEMS, INC.www.hiplainsystems.comhiredhand5@cs.com800-327-8295• Incorporating biosecuritymeasures• Vaccinating with a broad-spectrumvaccine that provides protectionagainst BVD Types 1 and 2Because NCP and CP biotypesdistribute through the body differently,research shows that the immunesystem responds differentlyto them, as well. In a research paperpublished in the Journal ofGeneral Virology, Lambot et al. investigatedimmune response differencesof calves infected with a pairof CP and NCP BVD. Results foundthat the NCP biotype produced ahigher and more rapid antibody responsethan the CP virus.In a different research trial, Arsenal®4.1, a modified-live vaccinecontaining NCP and manufacturedby Novartis Animal Health US, Inc.,found that it had a larger, faster antibodyresponse than a vaccinecontaining only CP Type 1.Bosch recommends consultingwith your veterinarian to determinethe best way to control BVD. ♦Five Nations Beef AllianceAgrees on Trade ReformThe national beef associationsof Australia, Canada, Mexico, NewZealand and the U.S. met in Australiarecently and reached a consensuson several items, accordingto NCBA.Among the agreements was aconsensus on trade reform. TheFive Nations Beef Alliance willcontinue to push for further tradeliberalization in the Doha Round ofWTO negotiations. The group supportsexpanded market access viathe removal of tariff and non-tariffbarriers, elimination of export subsidiesand substantial reductionsin domestic support.To achieve fair trade, the allianceurges all beef importing countries toensure that sound science based onOIE guidelines remains the basis forresolving sanitary and photosanitaryissues.♦Circle No. 129 on Reply28 FEED•LOT <strong>February</strong> 2007
Circle No. 130 on Reply