Results of an epidemiological survey of enzootic bovine leukosis in the northern part of Lower Saxony and a preliminary communication of an examination into relationship between BLV-antibody development and calving.

The Agar-Gel-Immunodiffusion-Test as proposed by EEC has been carried out during the last 2 1/2 years within a defined test area of Lower Saxony. About 500 leukosis-infected herds with a total of about 20.000 head of cattle have been tested five times now within three to six months sequences. The AGIDT has proved to be an easy and very practical test for routine diagnosis in large scale surveys. Our results described again show the superiority of the glykoprotein-antigen over the ether-treated p24-antigen in the AGIDT. Slaughter of AGIDT-reactors within this population led to a fast decrease of leukosis-infection as detected by the test. Epidemiological herd-data show, that spreading of infection within a herd depends largely on direct contact between infected and noninfected animals. Moreover our data give rise to the suspicion that the manipulations during blood-sampling seem to be implicated in the spread of the disease within a herd. Possible reasons for inconsistencies of antibody-titer in infected animals are discussed.