What is the treatment for bovine cough?

Bovine Cough: Treatment Approach

For bovine cough associated with bovine respiratory disease (BRD), administer florfenicol 20 mg/kg IM with a second dose 48 hours later, or tulathromycin as a single-dose alternative, targeting the bacterial pathogens Mannheimia haemolytica, Pasteurella multocida, and Histophilus somni. 1, 2

Initial Clinical Assessment

Recognize that cough is the single most reliable clinical sign associated with pneumonia in cattle across all production types and ages, though its sensitivity as a standalone diagnostic criterion remains limited (37.4% sensitivity, 85.7% specificity). 3

Key clinical parameters to evaluate:

• Spontaneous or induced cough - the only clinical sign consistently associated with ultrasound-confirmed lung consolidation in dairy, beef, and veal calves 3
• Rectal temperature ≥39.4°C - significant in beef and veal calves, though less reliable in dairy calves 3
• Respiratory rate and pattern - acute respiratory distress with rapid, shallow, open-mouth breathing suggests severe disease or atypical interstitial pneumonia 4, 5
• Duration of clinical signs - animals may progress from clinically normal to severe respiratory distress within 12 hours in acute cases 4

Antimicrobial Treatment Protocol

First-Line Therapy: Florfenicol

For treatment of BRD, administer florfenicol (Norfenicol) 20 mg/kg (3 mL/100 lbs) by intramuscular injection, with a mandatory second dose 48 hours later. 1

• Alternative single-dose regimen: 40 mg/kg (6 mL/100 lbs) subcutaneously in the neck only, not exceeding 10 mL per injection site 1
• Critical injection site: Use only the neck for subcutaneous administration to minimize tissue reaction and trim loss at slaughter 1
• Expected response time: Clinical improvement should be evident within 24 hours; if no positive response within 72 hours, re-evaluate the diagnosis 1

Alternative Therapy: Tulathromycin

Tulathromycin (DRAXXIN) is indicated for treatment of BRD associated with Mannheimia haemolytica, Pasteurella multocida, Histophilus somni, and Mycoplasma bovis in calves, offering single-dose convenience. 2

Differential Diagnosis Considerations

Atypical Interstitial Pneumonia (AIP)

If cattle present with acute respiratory distress, open-mouth breathing, and rapid progression despite being clinically normal 12 hours earlier, consider atypical interstitial pneumonia rather than infectious BRD. 4, 5

• Causative agents: L-tryptophan metabolites (3-methylindole) from lush pasture, perilla mint, moldy sweet potatoes 4, 5
• Pathophysiology: Metabolic activation of xenobiotic compounds causing Clara cell and type I alveolar epithelial cell death 5
• Treatment limitation: Primarily symptomatic and often ineffective; prevention through pasture management is key 4
• Seasonal pattern: Predominantly occurs in late summer or fall when cattle are moved to lush pasture 4

Infectious BRD

BRD results from multifactorial interaction of stressors, animal susceptibility, and respiratory pathogens that are ubiquitous in cattle populations. 6

• Primary bacterial pathogens: Mannheimia haemolytica, Pasteurella multocida, Histophilus somni 1, 2
• Secondary pathogens: Mycoplasma bovis, viral agents 2, 6
• Predisposing factors: Stress from transport, weaning, commingling, environmental changes 6

Treatment Algorithm

1. Identify cough (spontaneous or induced) as primary clinical indicator 3
2. Assess fever (≥39.4°C) and respiratory distress severity 3, 4
3. If infectious BRD suspected: Initiate florfenicol 20 mg/kg IM immediately, repeat in 48 hours 1
4. If acute respiratory distress with rapid progression: Consider AIP; remove from toxic pasture, provide supportive care 4, 5
5. Evaluate response at 24-72 hours: If no improvement, re-evaluate diagnosis and consider alternative pathogens or non-infectious causes 1

Critical Pitfalls to Avoid

• Do not delay antimicrobial treatment - early recognition and treatment are essential for effectiveness in BRD 6
• Do not exceed 10 mL per injection site when using subcutaneous florfenicol 1
• Do not inject subcutaneous florfenicol outside the neck - other sites cause more severe tissue reaction 1
• Do not rely on cough alone for individual animal treatment decisions - sensitivity is too low (37.4%) for antimicrobial stewardship 3
• Do not assume all respiratory disease is infectious - AIP requires different management focused on toxin removal rather than antimicrobials 4, 5

Prevention Strategies

Address management procedures to minimize stressors rather than relying solely on vaccination, as BRD pathogens are ubiquitous and stressors are necessary to initiate disease. 6

• For AIP prevention: Deny access to lush pasture after prolonged dry periods, eliminate toxic plants, provide adequate forage 4
• For infectious BRD: Minimize transport stress, optimize ventilation, reduce commingling of cattle from different sources 6