Grundriß der Ökologie

Ohne Zusammenfassung     

Procoagulant activity in respiratory tract secretions from horses with chronic pulmonary disease

Cell-free supernatants (sol phases), obtained after centrifugation (50,000 x g for 45 minutes) of respiratory tract secretions from horses with chronic pulmonary disease, were assayed for procoagulant activity (PCA) in a one-stage clotting assay. Of the 103 specimens tested, 59% (61) contained PCA. Procoagulant activity was detected most often in respiratory tract secretions of severely affected horses and was correlated with the quantity of neutrophils in the respiratory tract secretions. In 12 of the 17 secretions tested, the clotting time was decreased in a dose-dependent manner. However, in the coagulation assay, some reversal of PCA or inhibition of coagulation was observed in 4 secretion specimens when greater volumes of sol phase were added. Procoagulant activity was characterized tentatively as tissue factor, because it was temperature stable and was inhibited by phospholipase C and by concanavalin A. Clotting was induced in factor VIII-deficient human plasma; however, with the exception of 1 respiratory secretion specimen, clotting was not enhanced in factor VII-deficient human plasma. Procoagulant activity is a useful indicator of airway inflammation.     

The effect of blood-sucking diptera on the weight of grazing heifers

It was demonstrated experimentally that bloodsucking dipterans (gad-flies, gnats, midges, black flies) influenced negatively weight increments of grazing heifers and that it was suitable to treat the heifers with repellents; 10% water emulsion of the repellent diethyltoluamide was used for heifer spraying in the intervals of 48 hours. Over the 66 days of the experiment, the total live weight of one heifer from the test group increased by 5.00 kg, in comparison with the controls. The coefficient of loss per untreated animal was 105.00 Kcs., the returns of investments per 1.00 Kcs of investment costs were 1.90 Kcs. Owing to worse climatic conditions in the experimental years which significantly differed from meteorological conditions in the previous four years, which ensued from mathematico-statistical evaluation, differences in weight increments over the period of study were statistically insignificant.