BISONIANA. LXXX The Hematology of the Free-ranging European Bison

This paper presents the values of hematological parameters and indices for 46 European bison, Bison bonasus (Linnaeus, 1758), 37 of which were free-ranging bison and 9 bisons kept in enclosures. The samples were taken from bison shot during the winter period. Significant differences were found in some blood values connected with the age of the animals examined. In sexually mature bison over 4 years old from the free-ranging herd hemoglobin value, thickness of erythrocytes, mean corpuscular hemoglobin and mean corpuscular volume indices are significantly higher than in younger animals. The eosinophil per-centage increases with the animals ' age and is significantly lower in calves than in older animals. The number of lymphocytes is significantly lower in the group of oldest animals than in calves. The lymphocyte: neutrophil index decreases regularly with increse in the animals ' age. Comparison was made of the blood values for the European bison, American bison, Bison bison (Linnaeus, 1758) and domestic cattle. Attention has been drawn to the frequency of occurence of invasive diseases among the European bison examined (from 12 to 82 % in dif-ferent age groups) and also to the commonness of other diseases, which might have contributed to the wide range of variations in hematological data