Infectious Bovine Rhinotracheitis (IBR)

IBR is a viral respiratory disease caused by bovine herpesvirus 1 (BHV-1). The virus can also cause a mild venereal infection in adult cattle or a brain infection in calves. IBR is a highly contagious disease of the upper respiratory tract and can lead to serious primary or secondary pneumonia.

Effects 

The virus is shed in respiratory secretions and in the semen of infected bulls. Once infected by BHV-1, an animal mounts an immune response, but the virus is not completely eliminated and remains as a latent infection. When a latently infected animal is subjected to stress, the virus is shed, although there are usually no clinical signs of disease. Latent carrier animals are important in IBR epidemiology as a source of infection.

Herds with endemic IBR suffer mainly from low-grade problems associated with calf pneumonia, decreased fertility and occasional abortions. More serious problems such as milk drop, respiratory disease, abortions and an increase in calf pneumonia are seen on farms that have not been exposed to IBR before, with extremely severe and dramatic respiratory signs in some cases. However, subclinical infection and seroconversion in a naïve herd was also reported.

In calves, concurrent respiratory and neurological signs have been reported consequences of BHV-1 infection where the collostral antibody protection was suspected to be poor.

Diagnosis 

The clinical signs of the disease are nasal discharge, fever and conjunctivitis. Acute disease in dairy cattle is usually accompanied by a severe and prolonged drop in milk production.

Adult cows may also suffer from abortion and reduced fertility. Animals suffering from IBR are highly susceptible to secondary bacterial infections. 

 

This information was taken from:

http://www.vetsweb.com/diseases/infectious-bovine-rhinotracheitis-ibr-d233.html

  

For more information see:

http://www.organicvet.co.uk/Cattleweb/disease/ibr/ibr1.htm

http://www.iowabeefcenter.org/pdfs/bch/03220.pdf