[Pathogenic effect of strains of specific serogroups of Escherichia coli on the development of bovine mastitis. III. Blood changes].

Colimastitis was evoked in 14 cows which were injected into the udder E. coli strains (pathogenic) from the field, belonging to serological groups: 093, 086, 010, non pathological (museum) strains from groups: 0132, 0120, 093 and E. coli endotoxin (serogroup 093). Two cows were used for the studies of each strain and endotoxin. From the animals blood was taken three times before and after 2, 4, 6, 9, 12, 18, 24, 36, 48 hours and 3, 4, 5, 6, 7, 10, 14 days of the infusion of the strains or endotoxin into the udder. In the serum all cows the presense of endotoxin was found between the 4th and 9th hour since the infection. The level of free histamine was also found to increase (in the 2, 4 and 6th hr), and to decrease (in the first 12 hrs), and then an increase of the titre of specific antibodies. In the first 18 hrs after the infection strongly expressed leucopenia was observed. It was shown that general symptoms accompanying colimastitis were associated with the presense of endotoxin at an elevated level of free histamine in blood circulation.