The Pathology of Abortion Caused by the Virus of Infectious Bovine Rhinotracheitis

Abstract
The fetal lesions which characterize abortions caused by the virus of infectious bovine rhinotracheitis are focal necrotizing hepatitis, necrotizing placentitis, and irregularly distributed focal necrotic lesions in other organs. The abortions occur 18 to 64 days after experimental exposure of the dam. The lesions are quantitatively and qualitatively the same whether in response to infection by vaccine or field strains of the virus. The pattern of abortions which occurred in one herd following vaccination is reported.