Bovine Respiratory Disease Complex (BRD)
03 Sep 2021
Bovine Respiratory Disease Complex (BRD or “shipping fever”) is a common disease syndrome in intensively managed cattle such as feedlot animals or housed dairy cattle. Recently, North Coast Local Land Services district veterinarians are seeing an increased incidence of the disease in extensively managed beef herds, particularly in calves and weaners. The syndrome is not one specific disease but a complex interaction between commensal viruses and bacteria that usually live harmlessly in the respiratory tract of healthy cattle. However, under certain circumstances can become pathological and cause overt disease in affected animals.
BRD generally presents as pneumonia but can occasionally result in sudden deaths in severely affected or infrequently observed animals. Cattle can display clear to thick mucoid nasal discharge and may stand with their head and neck extended to aid breathing. Breathing can be rapid and shallow or regular but loud and laboured. Coughing is another common symptom, generally starting as a shallow regular cough and progressing to a deep hacking cough. All these symptoms are worsened with physical exertion (such as moving paddocks, being brought to the yards etc.).
The syndrome is usually triggered by a viral infection + subsequent opportunistic bacterial invasion of the airways. The primary cause is stress, which in extensively managed beef animals is typically due to:
- Social stress (weaning, social disruption)
- Commingling near strange animals (transport, saleyards)
- Feed or water change (including a rain event and green flush of feed)
- Extreme weather (extended rainy weather, sudden cold snap)
Once established in a herd, BRD can be complicated to cure and eradicate. Affected animals need specific medications requiring a consult with a private veterinarian and benefit from nursing care which can be very time-consuming and labour-intensive.
However, BRD is very manageable and often preventable using a combination of vaccination (there are several products available, suitability of each product will depend on your operation), and management techniques to minimise stressful events (especially the “stacking” of multiple stressful events at one time eg weaning + transport). If you are buying in youngstock, ask if they have been vaccinated. Even better, request a cattle health declaration document at purchase!
If you would like to develop a BRD prevention program, please contact your closest Local Land Service District Veterinarian.