PREVALENCE AND CLINICAL SYMPTOMS OF PERSI STENT BVD-VIRUS INFECTION IN CATTLE HERDS OF LOWER-SAXONY

In Lower Saxony within two years 20,253 cattle of 329 herds were teste d by using an antigen-capture-ELISA for persistent BVD viral infection s, 428 (2.1 percent) cattle persistently infected (p.i.) with BVD viru s in 149 (45.3 percent) herds were detected, Of these persistently inf ected animals, 256 were retrospectively monitored for clinical symptom s indicative of BVD viral infection, 123 (48 percent) cattle showed no clinical symptoms while in 133 (52 percent) p.i. cattle growth retard ation and unthriftyness (''runting syndrome'') was observed, Most of t he p.i. cattle were found at an age of up to 1 year (66 percent) while only 10 percent were older than 2 years, The results are discussed wi th regard to the necessity of finding and eliminating p.i. cattle, The BVD control programme presently patronized is demanded mainly for use in cattle breeding herds.