class 10

BRD, also known as Bovine Respiratory Disease Complex or Shipping Fever, is a critical issue in cattle, particularly in feedlot and dairy settings.
It is a leading cause of morbidity and mortality, with significant economic impact due to medication costs and reduced growth efficiency.
Young calves (under six months) are most affected, while mature lactating cows rarely exhibit the disease.

Key Factors Contributing to BRD:
- Environment: Stressful conditions increase disease risk.
- Pathogens: Bacteria and viruses present in the environment can trigger disease.
- Host Factors: Individual animal health, vaccination status, and overall well-being play critical roles.

Stressors: Stress from weaning, transportation, environmental conditions (heat vs. cold), and handling significantly impact calf health.
Pathogens: Commensal bacteria in the upper respiratory tract can cause disease if they migrate into the lower respiratory tract, often following viral infections or stressors.
Major Pathogens:
- Bacteria: Mannheimia haemolytica, Pasteurella multocida, Histophilus somni, Mycoplasma bovis.
- Viruses: Bovine viral diarrhea (BVD), Bovine respiratory syncytial virus (BRSV), Parainfluenza, Infectious bovine rhinotracheitis (IBR), Bovine coronavirus.

Disease Development: As the respiratory tract is disrupted (e.g., due to stress or viral infection), bacteria that are typically harmless can proliferate and invade deeper lung tissues, leading to bronchopneumonia.
Symptoms: Increased respiratory rate, coughing, ocular and nasal discharge, depression, and decreased feed intake.
Inflammatory Response: Introduction of pathogens causes local inflammation, leading to systemic signals of disease.

Management Recommendations:
- Investing in calf comfort (e.g., appropriate bedding, good ventilation, environment control) may reduce disease occurrence more effectively than additional vaccines in some cases.
- Vaccination protocols should focus on both viral and bacterial pathogens, with particular emphasis on effective vaccination schedules and optimizing timing (i.e., during non-stressful periods).

Common Treatments:
- Antimicrobials are the primary treatment for clinical BRD, with around 99% of affected cattle receiving injectable antibiotics.
- Anti-inflammatories like NSAIDs (e.g., Banamine) are often used in conjunction with antimicrobials to reduce inflammation.
- Supportive care may include vitamin C, fluids, and electrolytes, particularly for dehydrated animals.

Importance of Vaccination:
- Vaccination against viral and bacterial pathogens has become more prevalent, with >90% of feedlots now utilizing viral vaccines and increased use of bacterial vaccines.
- Vaccination should ideally be administered before stressors such as transportation or weaning.
Considerations: When developing vaccination programs, understand the specific pathogens endemic to your region and the health status of incoming animals.

Economic losses attributed to BRD are substantial, particularly in light of high cattle prices.
Attention to calf health and proactive prevention measures are crucial for mitigating loss.