Chronic Respiratory Disease (CRD)

Chronic respiratory disease (CRD) is a long-term (chronic) condition defined by persistent infection despite appropriate and aggressive treatment; it is non-reversible and often slowly progressive. Chronic infection causes irreversible changes in the lungs and nasal passages. Cure of infection in these animals is unlikely, and chronic recurring bovine respiratory disease (BRD) is common. 
Chronic respiratory disease is initiated by multiple bacteria and viruses. Prevention for viruses via vaccination, as well as secondary bacterial treatments are possible solutions.