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The usefulness of soluble markers in indirectly differentiating inflamed quarters from healthy quarters of 30 Holstein Friesian cows was tested over a follow-up period of 20 weeks. In comparison to N-acetylfl-D-glucosaminidase (NAGase), lactate dehydrogenase (LDH), Na', Kf and CI-the somatic cell counts (SCC) were determined in foremilk samples. The soluble parameters were measured by means of an autoanalyzer system (Beckman CXSCE) equipped with solid state ion electrodes. Due to dfferent types of inflammatory reactions it is considered to be advantageous to perform two tests in parallel for assessing the mammary gland status. CeU-damaging processes should best be detected by measuring elevated LDH activity, whereas the impairment of the blood-udder barrier is recorded by the respective elevation of the indicators Na+ and Cl-. Among all variables, SCC included, the soluble parameters showed the least dispersions, whereas those of SCC were the most unfavourable in tlus respect. Moreover, NAGase/LDH and Na'/CI-among all variables had the highest correlation coefficients of 0.85 and 0.86, respectively. Threshold values as decision limits are proposed. Additionally, an inter-quarter comparison and evaluation improved the diagnostic value of each indirect mastitis parameter analyzed. By means of discriminant analysis, it is shown that the distribution of inflammation within the udders of this herd was unequal.

Three rat liver foci bioassays have been compared with respect to their sensitivity by the histochemical demonstration of preneoplastic foci, and by the biochemical determination of alterations in enzyme activities of serum indicating hepatotoxicity. We studied the initiation/promotion schedules according to Oesterle and Deml (A), and according to Pereira (B, Broad Spectrum Protocol), and the initiation/selection protocol according to Tatematsu et al. (C), with diethylnitrosamine (DEN), given as a single initiating dose of 10 and 30 mg/kg body wt respectively. With all schedules Sprague-Dawley rats, either females, 3 weeks old (A), or males, 6 weeks old (B, C) were used. For promotion polychlorinated biphenyls (A) or phenobarbital (B) were administered. Selection was performed with 2-acetylaminofluorene (C). The rats in schemes (B) and (C) underwent partial hepatectomy one day prior to initiation. The number and total area of foci deficient in adenosine-5'-triphosphatase (ATPase) and positive in gamma-glutamyltranspeptidase (GGTase) was evaluated. In the complete schedule with 30 mg of DEN in system (A) foci incidence exceeded that of the other systems by about 7-fold (ATPase) and 2-fold (GGTase) respectively. The lower dose of DEN and all control experiments resulted in a respective lower foci yield. With scheme (C), but not with schemes (A) and (B), e.g. serum fructose-1.6-bisphosphatase and alkaline phosphatase were increased, suggesting liver cell damage. Thus tested with DEN, scheme (A) is most sensitive and causes a low impairment of animals' welfare.

A direct and an indirect antibody enzyme-linked immunosorbent assay for duck yolk IgY and duck serum IgY was developed and tested on egg yolk and serum of ducks vaccinated with Riemerella anatipestifer (Ra). Tests were performed either with primary antibodies labelled with horseradish peroxidase or with alkaline phosphatase-labelled secondary antibodies reacting with specifically bound rabbit anti-duck IgY antibodies, respectively. Ra-specific IgYs in egg yolk from three ducks increased rapidly at day 8 after the first of two vaccinations. In two ducks, the IgY titre persisted on a high plateau for 3 months. The concentration of Ra-specific IgYs in the serum of the progeny of vaccinees decreased between day 3 and day 10 after hatching. The fraction of total IgYs decreased less but also significantly. It was shown that antibodies were vertically transmitted and therefore protect offspring against Ra infection at least during the first week after hatching. The test design with anti-IgY rabbit antibodies is further suitable to detect other specific antibodies if respective antigens were fixed on solid phases.

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