Bovine respiratory disease (BRD) is the most common and costly disease affecting beef cattle in the world. It is a complex, bacterial infection that causes pneumonia in calves which can be fatal. The infection is usually a sum of three codependent factors: stress, an underlying viral infection, and a new bacterial infection.
In the Nigerian beef industry, BRD continues to be the primary cause of morbidity and mortality in feedlots. It has contributed to losses in performance, carcass quality and health. Notably a total infections of 764 Cattles recorded in Nigeria’s northern state of Kaduna in 2019.
This disease can damage the defence mechanisms of the upper respiratory tract and predispose to secondary bacterial infections of the lungs. In the early stages, BRD typically presents as inappetence with cattle appearing hunched and lethargic.
As the disease progresses coughing and nasal discharge may be seen. Cattle may appear depressed and withdrawn from the main herd. In many animals the disease may go unnoticed, silently impacting weight gain and meat quality.
The disease is spread by direct contact with an infected animal, through infected droplets in the breath.
Not all affected animals will show obvious signs during a respiratory outbreak, but they are still likely to suffer a setback in performance. Early identification of affected cattle is vital, and pens of cattle should be checked daily.
Bovine respiratory disease is best prevented by a combination of good management, appropriate building design and ventilation, and effective vaccination against the major pathogens on that particular unit well before the risk period.
Causes of Bovine Respiratory Diseases
This disease is multi-factorial including the following causes:
- Stress – is a major predisposing factor to Pneumonia outbreaks. Stress can arise from: Passage through marts, Commingling, Weaning, castration, dehorning
- Infectious agents: Bacteria infections are frequently isolated from the lungs of sick cattle. These pathogens are associated with a high mortality rate. Other pathogens that may also be responsible for disease including: Respiratory viruses, Parasites e.g. lungworm may also contribute to disease.
- Management: The environment in which animals are kept, nutrition and management of animals may all contribute to increases in pneumonia incidence on individual farms.
Symptoms of Bovine Respiratory Diseases
Clinical signs of BRD in cattle depend on many factors including  the age of the animal, the causative organism(s) and the stage of the disease.
General signs include:
- Fever – The connection between BRD and fever is extremely strong. BRD is one of the most common causes of fever. Fever is always one of the earliest signs of the BRD complex.
- Depression.
- Lack of appetite.
- Dullness
- Rapid, shallow breathing.
- Coughing
- Serous (watery), then purulent (pussy), and/or bloody nasal and eye discharge.
- Salivation.
Diagnosis
Diagnosis of the disease-causing agents involved in bovine respiratory disease on your farm will require assistance from your veterinarian. Knowing the specific cause allows specific prevention strategies and treatment protocols to be put in place.
Treatment and Control
- General animal husbandry can also help reduce the risk of disease. Providing clean dry bedding, avoiding overcrowding, using low stress handling techniques, proper ventilation of barns, and minimizing dust can help to reduce disease
- Vaccinations exist for several biological BRD precursor. Vaccines are not completely effective in stopping the disease, but are merely helpful in mitigation. Many of the problems with vaccine effectiveness rest with improper use. Failing to time vaccine doses appropriately, or not administering them before shipping.
- In the absence of vaccination, antibiotics can help to stop the bacterial factors of the disease.Â
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