Bovine Respiratory Disease: Welfare & Prevention

Bovine Respiratory Disease Complex

Bovine respiratory disease (BRD) is the most economically significant and welfare-impactful disease in cattle globally. Particularly devastating in young cattle at housing, weaning, and during transit, BRD causes acute pain, chronic lung damage, and significant mortality. Its prevention and rapid treatment are central welfare priorities.

Aetiology

BRD is multifactorial — viruses impair immune defences, allowing secondary bacterial infection to establish pneumonia:

Primary viral pathogens: IBR (Infectious Bovine Rhinotracheitis — BHV-1), BVDV (Bovine Viral Diarrhoea Virus), BRSV (Bovine Respiratory Syncytial Virus), PI3 (Parainfluenza 3)
Secondary bacterial pathogens: Mannheimia haemolytica, Pasteurella multocida, Histophilus somni, Mycoplasma bovis
Risk factors: Stress (weaning, transport, mixing), poor ventilation, high stocking density, concurrent disease, nutritional deficiency

Welfare Impacts

Acute fever, dyspnoea, and nasal discharge cause significant discomfort
Chronic lung consolidation reduces respiratory capacity permanently in survivors
Pain from pleuritis (lung lining inflammation) is particularly severe
Reduced growth rate and performance reflect ongoing welfare compromise
Chronic mycoplasma infection causes persistent, difficult-to-treat welfare harm

Clinical Signs and Scoring

DART scoring (Depression, Appetite loss, Respiratory signs, Temperature) provides systematic BRD detection:

Temperature >39.5°C — fever indicator
Increased respiratory rate and effort
Nasal and ocular discharge
Dull demeanour and reduced appetite
Reluctance to move or stand apart from group

Treatment and Welfare

Antibiotics: Prompt treatment with appropriate antibiotics (tulathromycin, enrofloxacin, florfenicol — based on culture and sensitivity) reduces duration and severity
NSAIDs: Meloxicam alongside antibiotics significantly improves welfare outcomes — reduces fever, pain, and inflammation
Timing: Every hour of delay in treatment worsens prognosis; treatment within 24 hours of clinical signs dramatically improves outcomes

Prevention

Comprehensive vaccination programme (IBR, BRSV, PI3, BVD, M. haemolytica)
BVD eradication at herd level through testing and removal of PI animals
Housing design: appropriate ventilation (0.04m²/bovine unit at ridge; positive airflow)
Reducing stocking density and minimising mixing of unfamiliar animals
Colostrum management to ensure adequate passive immunity in calves
Nutritional management to support immune function

Key Takeaways

BRD causes widespread, preventable welfare harm. Combining comprehensive vaccination, rigorous early detection (DART scoring), prompt treatment including NSAIDs, and housing management is the most effective approach to reducing the burden of this important disease.