[PCB concentration in hair, blood, tissues and secretions of chronically exposed dairy cows, fattening bulls and calves].

Fattening bulls (n = 8) and cows (n = 10) affected chronically with PCB were kept in barns on PCB-free feeding (silage, straw, concentrates). The cows were dried off. The kinetics of PCB-concentrations in hair, blood and feces were examined.

[PCB concentrations in hair, blood, tissues and secretions of chronically-exposed dairy cows, fattening bulls and calves. 1. Course and relation of some polychlorinated biphenyls in hair, milk and tissues in exposed nursing cows and conventionally raised dairy cows].

20 cows contaminated chronically with PCB were kept as nurse cows or in a tie-stall. The contamination in different substrates (hair, milk, blood, feces) was examined for a period up to 8 months. The distribution of PCB in the carcass of some animals was registered in addition.

[The use of ELISA systems for control of epizootics: safety of test standards using batch assays].

One of the advantages of ELISA techniques is to achieve a higher degree of safety by standardization. Bases of these standardizations should be, if available, international or national standards in combination with cutoff definitions. The cutoff definitions should be expressed, separate for the main kinds of samples, defined as a dilution of the standard.

[Experiences in the control of brucellosis in cattle herds in the government district of Hannover].

Caused by imported beef cattle new outbreaks of Brucellosis (subtype III) were observed in the government district of Hannover, which was "Brucellosis free" over a long period. With the aim to interrupt the series of infections from herd to herd it seemed to be necessary to introduce a herd screening system including frequent tests. It was not possible to screen the herds by the usual way of blood serum testing because of reasons of practicability and economy.

[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.