[Leucosis diagnosis in cattle using the Sudan black B staining method on granulocytes and monocytes]

In the peripheral blood of healthy cattle and cattle suffering from leucosis a positive reaction with Sudan black B was found in neutrophilic and eosinophilic granulocytes: in healthy cattle at an intensity from ++ to ++++, and in cattle suffering from leucosis it was somewhat slighter (++ to +++). This finding can, to a certain extent, help in the distinguishing of reactive lymphocytosis from the leucosis of cattle. Compared with granulocytes the reaction of monocytes is markedly weaker: in healthy cattle at an intensity from 0 to (++), and in diseased cattle from 0 to (+++). In the bone marrow there is a significantly weaker reaction to Sudan black B in the group of large cells (neutrophilic and eosinophilic promyelocytes and myelocytes); in the group of healthy and diseases cattle the reaction is weaker than in neutrophilic and eosinophilic granulocytes of the peripheral blood. The reaction obtained with Sudan black B for lipids can be used as an aid for the distinguishing of cells of the myeloid, monocytic, and lymphoid order of peripheral blood and bone marrow in cattle leucosis.