About Bovine Respiratory Disease Complex
Bovine respiratory disease complex (BRDC) affects beef and dairy herds worldwide causing significant welfare and economic impact. It is most prevalent in young calves in the first few months of life housed in close quarters. BRDC appears to be initiated by environmental stress combined with infections in the upper respiratory tract (URT), with resultant inflammation then allowing for the development of secondary infections in the lower respiratory tract (LRT).
The economic consequences of BRDC are globally significant. In the UK alone, it is estimated that BRDC affects 1.9 million animals at a cost of £60-£80 million per year due to illness and death. However, BRDC is also underdiagnosed, potentially by as much as 50%, suggesting that the impact of the disease could be much higher.
Management of BRDC by appropriate vaccination, early diagnosis of cases, and prompt appropriate treatment will help farmers minimise costs and maximise animal welfare and production efficiency. It is essential that management starts early because BRDC can be seen in very young calves: in one UK study across 11 herds, BRDC was diagnosed in over 45% of calves younger than nine weeks old, and 5% at only one week old1. A sound herd health plan that recognises and addresses the balance between the costs and benefits of BRDC protection should be the basis for on-farm management (see Figure 1). Such plans should also include regular reviews to check they are working, for example recording antibiotic usage and other data so that BRDC treatment rates, calf growth rates and mortality rates can be determined. Very high and very low treatment rates may indicate problems.
- Sometimes known as bovine pneumonia, bovine respiratory disease complex (BRDC) is a multi-factorial disease affecting mainly young stock in the first few months of life and is considered to have among the highest economic impacts of any infectious condition of cattle
- It is the result of multiple contributing factors – infectious agents, environmental factors, and stress-related – that lead to disease of the lungs
- The main clinical signs of BRDC are depression, discharge from the nose and eyes, coughing, abnormal breathing, gaunt appearance, and lack of appetite
- Infection also leads to blockages in lung tissue and loss of lung capacity, leading to significant morbidity and mortality if it is not treated successfully
- Moredun has recently developed a new diagnostic test that can detect four major viruses and four major bacterial pathogens involved in BRDC from a single sample, potentially allowing faster and more targeted treatment
- Disease management may also involve attention to housing, ventilation, nutrition (including adequate colostrum) and protection from adverse weather
- Farmers should discuss BRDC with their vet as part of an overall herd health programme. Diagnostic testing should be used to guide treatments and disease prevention and control strategies including vaccination