IBR
IBR is an acute, contagious respiratory disease of cattle caused by bovine herpesvirus type 1 (BHV-1), commonly affecting the respiratory tract and the reproductive system. It is highly contagious, resulting in rapid spread of respiratory disease among cattle in close confinement, particularly in feedlots and when groups of cattle are transported.
IBR is an acute infection usually characterized by visible signs, including sudden onset of fever, salivation, rhinitis (red nose), conjunctivitis (red, watery eyes), inappetance, and dyspenea (difficult breathing). The nasal mucosa and muzzle are distinctly inflamed, with abundant nasal discharge. Nasal lesions become large, consolidated hemorrhagic (red) areas or white plaques. In advanced cases, respiratory distress increases and open-mouth breathing is evident. If primary BHV-1 infection does not resolve in five to ten days, secondary bacterial infection can occur, leading to bronchopneumonia and death in complicated cases. The reproductive system may also become involved manifested by infertility problems, abortion, and birth defects.
In adult cattle, one of the early signs of BHV-1 infection is a reduction in milk yield.
Diagnosis may be made on clinical signs (fever, nasal discharge and conjunctivitis) and epidemiology. Additional examinations are often required for a definitive diagnosis. (E.g. laboratory tests).
In dairy cattle, prolonged drop in milk production, abortion and reduced fertility are also precursory signs.
There is no specific anti-BHV-1 therapy. The most appropriate treatment is antibiotic therapy designed to control secondary bacterial infection. Management practices designed to reduce stress, isolate infected animals, and provide adequate food and water will limit disease transmission and severity.
The prevention of IBR is based either on preventing the virus from entering the herd or vaccination. Vaccination with modified live virus (MLV) vaccines generally provides adequate IBR protection by helping prevent disease or reducing its severity. Parenteral (intramuscular or subcutaneous) and intranasally administered IBR vaccines are available, with intranasal (IN) products producing a rapid local immune response.
Traditionally, parenteral modified live virus IBR vaccines are not labeled for use in calves nursing pregnant cows because of the risk of shedding of the vaccine virus to pregnant cows, resulting in fetal infection and abortion.
