An encephalopathy with argyrophilic inclusions in a Holstein-Friesian cow

The brain of a 6-year-old Holstein cow, which showed progressive neurologic symptoms during several months, was examined by histopathologic methods. M any round or oval-shaped cytoplasmic inclusions were observed, mainly in ne urons of the temporal lobe and the hippocampus. Those inclusions were faint ly eosinophilic with hematoxylin and eosin and positive with Bielschowsky's silver stain. Immunohistochemically, the inclusions were recognized by ant iubiquitin and antiphosphorylated tau antibodies. Ultrastructurally, the in clusions were globular and well demarcated from the rest of the cytoplasm, lacked limiting membranes, and were mainly composed of straight fibrils abo ut 15 nm in width. The structure of the inclusions was similar to that of P ick bodies in Pick's disease of humans. The pathogenesis of this bovine con dition is not known.