[Control measures in officially acknowledged brucellosis-free and leukosis unsuspected dairy herds on the basis of bulk milk samples in combination with ELISA tests].
1. EC- and National Regulations. Since 1988 the EC-regulations accept in addition to the on Agar Gel Immunodiffusion test (AGIDT) based blood serum testing of cattle herds that are filed as "free from Enzootic Bovine Leucosis" the use of ELISA for this purpose. The regular testings in dairy cattle herds can be done alternatively with single or pooled milk samples, in other herds with pooled blood sera using ELISA. General condition is only a minimal sensitivity of the test to detect the European EBL Antibody Standard ("E4") in a dilution of 1:10 in negative serum or 1:250 in negative milk. Adequate national regulations are in preparation. The present limitation of pool sizes, blood maximum 50 animals without preparation steps 20, and milk after concentration treatment 50 cows is neutralized by proceedings in development of higher sensitive ELISA tests. This limitation should be canceled. Herd bulk milk samples without size limitations are accepted to be tested with "Milk Ring Test" by EC for the regular testings in filed "Brucellosis Free Dairy Cattle Herds". The alternative use of more sensitive (and more specific) ELISA tests for this purpose including the technical conditions is in a final discussion. 2. Scientific-Technical Base for Using the Chances of the Proceeding in the EC-Regulations. The realisation of the EC accepted or final discussed ELISA based bulk milk testing to control filed "EBL- and/or Brucellosis Free Herds" depends on some basic conditions like sensitivity, specificity, and variability of the ELISA systems. Field trials of more than 20,000 bulk milk samples in case of Brucellosis and more than 2,000 in case of EBL show the feasibilities and the limits of the ELISA systems in defining the status of the herds. The Brucellosis respectively the EBL situations of the dairy cattle herds tested in this trail were well known by history and by investigation of single animal blood samples using conventional tests. Special test run variations of pretested assays demonstrated the possibilities to define the EBL status of dairy cattle herds up to 50 lactating cows without preparation of the bulk milk sample and up 100 after concentration of the antibodies by the rennet-ammonium sulfate method. The concentration limit for detection of Brucellosis antibodies is 100 lactating cows. The bulk milk of smaller herds can be tested without concentration. On principle the evaluation of the test values bases on defined relations to a "weak positive" reference.(ABSTRACT TRUNCATED AT 400 WORDS)
Forschner
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Bünger
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Krause
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HP
Küttler
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D
D000818:Animals; D002007:Brucellosis, Bovine / Q000175:diagnosis* / Q000517:prevention & control; D002417:Cattle; D002418:Cattle Diseases / Q000175:diagnosis* / Q000517:prevention & control; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D007938:Leukemia / Q000175:diagnosis / Q000517:prevention & control / Q000662:veterinary*; D001909:Leukemia Virus, Bovine; D008892:Milk / Q000276:immunology*
Kontrollmassnahmen in amtlich anerkannten brucellosefreien und leukoseunverdächtigen Milchviehbeständen auf der Basis von Tankmilch-Proben in Kombination mit ELISA-Tests.