We studied the hide, neck knots, as well as the liver of calves infected intradermally with strain KOS-Haskovo of Bovid Herpes Virus 2. On the spot of the injection we found necrotic changes in the superficial strata of the epidermis, hydropic distrophy of St. spinosum and also eosinophil intranuclear inclusions in separate epithelial cells. Intranuclear acidophil inclusions were proved also in the macrophages of the lymph knots, whereas in the liver we found a reactive lithic micronecroses. The ontogenic cycle of development took place in the cytoplasm of the infected cell and during this process the nucleocapsid was formed in the nucleus, whereas the virion was formed in the cytoplasm with the membrane elements. It was proved that changes were due to the virus which has a wide range of alteration in the bodies of the calves.