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Bovine Respiratory Disease (BRD): The Complete Treatment Guide

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Bovine Respiratory Disease (BRD): The Complete Treatment Guide | Cattle Daily
Cattle Daily — Veterinary Health Guide 2026

Bovine Respiratory Disease (BRD): The Complete Treatment Guide

Updated May 2026  |  14-Minute Read  |  Veterinary Expert Reviewed

Quick Summary

Bovine Respiratory Disease (BRD) — commonly called shipping fever — is the single most economically damaging disease in the North American cattle industry, responsible for more antibiotic use, more death loss, and more performance impairment than any other cattle health condition. Understanding BRD means understanding the interplay between viral pathogens that suppress immunity, bacterial opportunists that cause the actual pneumonia, and the environmental and management stressors that create the vulnerability window when disease strikes. This complete guide covers the causes, clinical signs, scoring systems, antibiotic treatment protocols, metaphylaxis programs, vaccination strategies, and economic impact calculations that every cattle producer and herd manager needs to effectively prevent and manage BRD in 2026.

Table of Contents

  1. Economic Impact of BRD
  2. The Shipping Fever Complex Explained
  3. Viral Causes: The Immune Suppressors
  4. Bacterial Causes: The Pneumonia Producers
  5. BRD Risk Factors and High-Risk Cattle
  6. Clinical Signs and BRD Scoring Systems
  7. Diagnosis: When to Pull and How to Confirm
  8. Antibiotic Treatment Protocols 2026
  9. Metaphylaxis: Mass Treatment at Arrival
  10. Vaccination Programs for BRD Prevention
  11. BRD Impact and Treatment Outcome Chart
  12. Frequently Asked Questions

1. Economic Impact of BRD

Bovine Respiratory Disease is the most costly disease complex in the beef cattle industry — and its economic damage extends far beyond the visible costs of treatment and death loss. Every animal that goes through a BRD event, even a mild one treated successfully, carries a performance penalty for the remainder of its production life. Understanding the full economic burden of BRD motivates the investment in prevention programs that routinely generate 3–5 times their cost in avoided losses.

$3–$5B
Annual economic losses attributed to BRD in the U.S. cattle industry — the single largest disease cost category
16–45%
Percentage of high-risk cattle that experience BRD in the first 45 days after feedlot placement under standard management
$300–$500
Total economic loss per BRD case including treatment cost, reduced gain, carcass quality penalty, and death risk
40–50%
Reduction in lung consolidation lesions at slaughter achievable with effective preconditioning and metaphylaxis programs
The Hidden Costs Beyond Treatment The direct cost of BRD treatment ($15–$40 in antibiotics per case) is only a fraction of the true economic impact. The full cost per case includes: antibiotic cost ($15–$40), labor for identification and treatment ($20–$35), reduced average daily gain during illness ($30–$80 over the illness period), impaired lung function post-recovery reducing lifetime gain ($50–$150), higher carcass condemnation rate and dark-cutter incidence ($20–$80 per affected carcass), and death loss risk ($180–$350 per case as expected value at average case fatality rates). Total: $300–$500 per case when all costs are accounted for.

2. The Shipping Fever Complex Explained

BRD is not a single disease with a single cause — it is a complex interaction of viral infections, opportunistic bacterial infections, and host immunosuppression that typically unfolds over a predictable sequence following a stressor event. The term "shipping fever" captures the most common trigger — the transport, commingling, and environmental stress of moving cattle from their origin to a new location — but the same pathological sequence can be triggered by weaning, processing, weather extremes, or any other significant stress event.

The sequence begins with viral infection. BVDV (Bovine Viral Diarrhea Virus), IBRV (Infectious Bovine Rhinotracheitis Virus / BHV-1), BRSV (Bovine Respiratory Syncytial Virus), and PI3 (Parainfluenza-3 Virus) are the primary viral pathogens. These viruses are not usually fatal in themselves, but they damage the respiratory epithelium's mucociliary clearance apparatus, suppress neutrophil and macrophage function in the lungs, and create the vulnerable environment that allows normally non-pathogenic bacterial species to establish life-threatening pneumonia.

The BRD Pathogenesis Sequence: Stressor event (transport, weaning, weather) → Immunosuppression (cortisol surge, cold stress, crowding) → Viral infection (BVDV, IBR, BRSV, PI3) → Further immune compromise and respiratory epithelium damage → Bacterial colonization (M. haemolytica, P. multocida, H. somni, M. bovis) → Fibrinous or necrotizing pneumonia → Clinical disease (fever, depression, respiratory distress) → Treatment opportunity window (24–72 hours from first clinical signs) → Recovery or death depending on treatment timing and bacterial susceptibility.

3. Viral Causes: The Immune Suppressors

The viral component of BRD is primarily responsible for creating the vulnerability that allows bacterial pneumonia to develop. Understanding each primary viral pathogen informs vaccination program design — because preventing viral infection, or minimizing its severity, is the most fundamental BRD prevention strategy.

BVDV — Bovine Viral Diarrhea Virus
Disease Role The most immunosuppressive pathogen in the BRD complex. BVDV type 1 and type 2 strains cause profound suppression of neutrophil and lymphocyte function — dramatically increasing susceptibility to secondary bacterial infection. PI (Persistently Infected) cattle shed massive quantities of BVDV continuously and are the primary reservoir in commingled cattle. Key Facts PI cattle are born BVDV-infected after in-utero exposure; they test positive on individual PCR testing. Any PI animal in a pen dramatically increases the BRD rate for all susceptible penmates. Removing PI cattle (identified through PCR ear notch testing) from high-risk groups is one of the most impactful single BRD prevention interventions. Primary Viral — MLV Vaccine Critical
IBR / BHV-1 — Infectious Bovine Rhinotracheitis
Disease Role IBR causes severe upper respiratory tract infection — rhinitis, tracheitis, and conjunctivitis. Like BVDV, it suppresses pulmonary immune function and creates the vulnerability window for secondary bacterial pneumonia. Stress-induced viral reactivation from latently infected cattle can introduce IBR into previously stable groups. Latency BHV-1 establishes latent infection in trigeminal nerve ganglia. Stress (transport, processing, corticosteroid exposure) can reactivate the virus and cause clinical disease and shedding years after initial infection — even in vaccinated cattle. This reactivation phenomenon is why stress management remains important even in well-vaccinated herds. Primary Viral — Modified Live Preferred
BRSV — Bovine Respiratory Syncytial Virus
Disease Role BRSV is the most important viral cause of lower respiratory tract disease in young cattle and is particularly destructive to the alveolar architecture — causing syncytia (cell fusion) that destroys respiratory surface area. BRSV typically causes the most severe acute respiratory signs of the BRD viruses and can cause significant pneumonia even without secondary bacterial infection in susceptible animals. Seasonality BRSV outbreaks often occur in fall — coinciding with peak cattle movement, weather stress, and declining maternal antibody protection in calves. Fall-born calves going through their first weaning and transport are particularly vulnerable. MLV vaccines containing BRSV are essential for high-risk cattle. Primary Viral — High Virulence
PI3 — Parainfluenza-3 Virus
Disease Role PI3 is the "gateway" virus in the BRD complex — ubiquitous in cattle populations and typically causing mild clinical signs in isolation, but acting as a crucial facilitator that opens the respiratory tract to more serious viral co-infections and secondary bacterial invasion. PI3 alone rarely causes significant disease but is rarely found alone in BRD cases. Vaccination Note Vaccination against PI3 alone is insufficient BRD prevention. PI3 protection must be combined with BVDV, IBR, and BRSV in a comprehensive respiratory vaccine to provide meaningful protection against the full viral complex. All major BRD combination vaccines include PI3. Facilitator Pathogen

4. Bacterial Causes: The Pneumonia Producers

Following viral immune compromise, opportunistic bacteria that normally colonize the upper respiratory tract without causing disease descend into the lower respiratory tract and establish life-threatening pneumonia. These bacteria are the primary target of antibiotic treatment programs.

Bacterial Pathogen Prevalence in BRD Disease Characteristic Antibiotic Susceptibility Pattern Key Clinical Notes
Mannheimia haemolytica (Pasteurella haemolytica) Most common primary — 50–70% of cases Rapidly progressive fibrinous pneumonia; high fever; leucotoxin production damages white blood cells Generally susceptible to florfenicol, enrofloxacin, tulathromycin, tildipirosin; increasing macrolide resistance documented Speed of treatment critical — leucotoxin causes irreversible lung damage within hours of infection. Treat within 24 hours of first signs.
Pasteurella multocida Common secondary — 40–60% of cases Less acute than M. haemolytica; bronchopneumonia; often seen in combination with other pathogens Generally susceptible to most BRD antibiotics; more consistent sensitivity than M. haemolytica More common in BRSV-associated BRD; responds well to prompt antibiotic therapy
Histophilus somni (formerly Haemophilus somnus) Significant — 15–30% of severe cases Causes both BRD and thromboembolic meningoencephalitis (TEME); vascular lesions; sudden death possible Susceptible to florfenicol, oxytetracycline, sulfonamides; ampicillin may be effective Any case with neurological signs should raise suspicion for H. somni; TEME cases require urgent intervention
Mycoplasma bovis Increasingly significant — 20–40% of chronic/relapsed cases Causes chronic, non-responsive pneumonia; polyarthritis; otitis media in calves; INTRINSICALLY RESISTANT to all beta-lactam antibiotics Resistant to penicillin and cephalosporins (lacks cell wall); variable response to macrolides and tetracyclines; enrofloxacin may be effective Any cattle not responding to 2–3 treatment rounds should have M. bovis strongly suspected; culling may be more economic than continued treatment

5. BRD Risk Factors and High-Risk Cattle

BRD risk is not random — certain cattle populations and management scenarios consistently produce higher morbidity rates. Understanding these risk factors allows targeted prevention investment in high-risk groups while avoiding unnecessary metaphylaxis cost in lower-risk cattle.

  • Commingling from Multiple Sources: Cattle assembled from multiple farms bring diverse pathogen loads without shared immunity — each source population introduces pathogens to which other source populations are naive. Research consistently shows BRD morbidity 2–4x higher in cattle assembled from multiple sale barn sources compared to load-out direct from a single ranch of origin. Single-source cattle with documented health history carry the lowest BRD risk at placement.
  • Long-Distance Transport (6+ Hours): Transport duration is linearly correlated with BRD risk up to approximately 24 hours, after which risk plateaus. The primary mechanisms are: cortisol-mediated immunosuppression from stress and novel environment; dehydration reducing mucociliary clearance function; temperature and humidity extremes in trailer environments; and forced proximity with cattle of diverse health status.
  • Lightweight Calves Without Preconditioning: Lightweight, unweaned, or recently weaned calves entering the stocker or feedlot system without a preconditioning period are the highest-risk single cattle category for BRD. Maternal antibody waning, first-time exposure to respiratory pathogens, weaning stress, and transport stress all converge simultaneously. Preconditioned calves (VAC-45 program) have BRD morbidity rates 30–50% lower than non-preconditioned calves from equivalent sources.
  • Seasonal Factors (Fall Entry): Fall-placed cattle — the largest annual movement pattern — face the highest BRD risk of any seasonal cohort. Rapidly changing temperatures create thermal stress; humidity and atmospheric conditions favor viral survival and transmission; peak cattle movement maximizes commingling; and the weaning-to-placement transition is typically compressed. Fall placements historically run 5–15% higher BRD morbidity than spring placements of equivalent cattle.
  • Nutritional Status: Cattle in thin body condition (BCS 3 or below) at placement have significantly compromised immune function due to protein-energy malnutrition. Inadequate trace mineral status — particularly selenium, zinc, copper, and Vitamin E — impairs both innate and adaptive immune responses. Pre-arrival mineral supplementation in the cow herd and adequate trace mineral content in receiving rations are practical risk reduction strategies.

6. Clinical Signs and BRD Scoring Systems

Early and accurate identification of BRD is the most critical management skill for reducing its economic impact. The time between first clinical signs and treatment initiation is the single most important determinant of treatment success — and cattle left untreated for 48–72 hours after early signs develop have significantly worse outcomes than those treated at the first subtle signs.

Clinical Sign DART Score Severity / Clinical Significance Action Threshold
Depression / Attitude (D) 0 = Alert; 1 = Mildly dull; 2 = Moderately depressed; 3 = Severely depressed Attitude change is often the first observable sign — cattle stop competing at bunk, stand apart from group, show reduced response to stimuli Score 2+ warrants pull; Score 3 = emergency treatment
Appetite / Feed Intake (A) 0 = Normal; 1 = Mildly reduced; 2 = Not eating Reduced feed intake visible at bunk; animal standing back from crowd during feeding; not competing for hay Score 1+ combined with other signs = pull candidate
Respiration (R) 0 = Normal; 1 = Increased rate; 2 = Labored; 3 = Very labored with open mouth Elevated respiratory rate (>30 breaths/min), abdominal breathing, flared nostrils — indicates significant pulmonary involvement Score 2+ = pull immediately; Score 3 = emergency
Temperature (T) Normal: 101–102.5°F; Mild: 103–103.9°F; Moderate: 104–105°F; Severe: 105°F+ Rectal temperature most objective single BRD indicator — 104°F+ in a depressed animal is virtually diagnostic for BRD in high-risk receiving cattle 103.5°F+ in high-risk cattle with any other sign = treat; 104°F+ alone = treat
Nasal/Ocular Discharge 0 = None; 1 = Serous (clear); 2 = Mucopurulent Mucopurulent nasal discharge indicates active bacterial infection in lower respiratory tract; serous discharge is less specific Score 2 with other signs confirms BRD; contributes to total DART score
DART Total Score Sum of individual scores across all criteria Total DART score ≥4 has high sensitivity and specificity for BRD in high-risk receiving cattle Score 4+ = pull and treat; Score 6+ = aggressive treatment protocol
The "Eyes and Ears" Rule: The two most reliable early signs that a cattle pen walker should look for during twice-daily pen riding are: ear droop (one or both ears hanging lower than normal, indicating depression and systemic illness) and a runny nose with mucopurulent discharge visible on the muzzle. An animal showing both of these signs in the first 14–21 days after placement in high-risk cattle has an extremely high probability of being BRD-positive when pulled and should be treated immediately rather than watched for additional signs.

7. Diagnosis: When to Pull and How to Confirm

Accurate diagnosis of BRD — distinguishing it from other causes of fever and depression — is essential for appropriate antibiotic selection and avoiding unnecessary treatment. A confirmed DART score combined with fever above 104°F in a high-risk animal during the first 21 days of placement provides sufficient clinical basis for treatment in most feedlot and stocker protocols.

  • Rectal Temperature: The most objective, reproducible diagnostic data point. Record temperature for every animal that scores DART ≥4 before treatment — this creates a baseline for evaluating treatment response. If temperature is not above 103.5°F in an animal with clinical signs, reconsider whether another condition (lameness, hardware disease, other systemic illness) may be the primary problem.
  • Auscultation: Stethoscope evaluation of lung sounds is the gold standard for confirming pulmonary involvement — crackles, wheezes, and areas of silence (consolidation) indicate pneumonia. All cattle treated for BRD in an operation with a veterinary relationship should have lung auscultation confirmed at initial treatment. Workers performing chute-side treatment can be trained to recognize abnormal lung sounds as an additional confirmation tool.
  • Blood Work and Culture: Routine blood work is rarely practical in field BRD management, but a complete blood count (elevated total white cell count, neutrophilia with band neutrophils indicating acute bacterial infection) can be valuable in animals with atypical presentations or poor treatment response. Broncho-alveolar lavage (BAL) culture for Mycoplasma bovis should be considered in any animal that has failed 2–3 antibiotic treatment rounds — culture results guide antibiotic selection in refractory cases.
  • Response to Treatment as Diagnostic Confirmation: For field-level BRD management, response to appropriate antibiotic therapy within 48 hours (temperature returning toward normal, attitude improving) is both a treatment outcome indicator and retrospective diagnostic confirmation. An animal that shows no temperature reduction or clinical improvement 48 hours after appropriate antibiotic therapy should be re-evaluated for M. bovis, concurrent disease, treatment failure from resistant bacteria, or non-infectious conditions.

8. Antibiotic Treatment Protocols 2026

BRD treatment requires a veterinarian-client-patient relationship (VCPR) and a written herd health protocol — the Veterinary Feed Directive (VFD) framework and USDA antibiotic stewardship requirements mean that BRD treatment protocols must be developed with your veterinarian, not improvised at the chute. The following table covers the primary antibiotic options used under written veterinary protocols in the United States in 2026.

Drug (Class) Dose / Route Duration of Action Meat Withdrawal Spectrum Key Notes
Tulathromycin (Draxxin) — Macrolide 2.5 mg/kg SQ; single dose Long-acting — 14 day residual effect; single treatment protocol 18 days (beef cattle) Broad spectrum; M. haemolytica, P. multocida, H. somni; some M. bovis activity Most widely used single-dose BRD treatment; high tissue concentration; may be less effective against M. haemolytica with acquired resistance
Tildipirosin (Zuprevo) — Macrolide 4 mg/kg SQ; single dose Long-acting — similar residual duration to tulathromycin 14 days M. haemolytica, P. multocida, H. somni; comparable to tulathromycin Alternative single-dose option; often shows high cure rates in fresh BRD cases; shorter withdrawal than tulathromycin
Florfenicol (Nuflor) — Phenicol 20 mg/kg SQ q48h × 2 doses OR 40 mg/kg SQ once Moderate duration; dose-dependent 38 days (SQ), 28 days (IM) Very broad spectrum; excellent activity vs M. haemolytica, P. multocida, H. somni; active against Mycoplasma Excellent choice for BRD cases where macrolide resistance is suspected; effective against relapsed cases; long withdrawal limits use in short-fed cattle
Enrofloxacin (Baytril) — Fluoroquinolone 7.5–12.5 mg/kg SQ once Long-acting; single dose 28 days Broad spectrum; excellent M. haemolytica; best available activity vs M. bovis; H. somni Reserved for cases failing other treatments due to FDA VFD category; potent fluoroquinolone — antimicrobial stewardship requires veterinary oversight
Oxytetracycline (LA-200) — Tetracycline 20 mg/kg IM q48h or LA formulation per label Moderate; multiple dose regimens common 22–28 days Broad spectrum; useful for H. somni; less reliable vs M. haemolytica due to acquired resistance in many populations Lower cost; OTC availability; useful in early-stage cases or where broad pathogen coverage at lowest cost is priority; significant resistance concern
Ceftiofur Crystalline Free Acid (Excede) — Cephalosporin 6.6 mg/kg SQ behind ear Long-acting — 7-day residual 13 days M. haemolytica, P. multocida, H. somni; NOT active vs Mycoplasma IMPORTANT: No Mycoplasma activity (beta-lactam); short withdrawal advantage; often used as first treatment in high-turnover stocker cattle
Treatment Failure Protocol: When an animal has not improved temperature or attitude within 48–72 hours of appropriate initial treatment ("no response" or "relapse"), the second treatment should ideally switch antibiotic class (e.g., from macrolide to florfenicol or fluoroquinolone) rather than repeating the same drug. Third-treatment relapses strongly suggest Mycoplasma bovis involvement or antibiotic resistance — consult your veterinarian for culture results and consider whether treatment economics justify continued therapy or whether culling is more appropriate for that individual.

9. Metaphylaxis: Mass Treatment at Arrival

Metaphylaxis — the administration of a long-acting antibiotic to an entire group of high-risk cattle at arrival processing, before clinical disease appears — is one of the most cost-effective BRD management tools available when used in appropriate risk categories. It is neither routine blanket antibiotic overuse nor avoidance of necessary treatment — it is a risk-based decision tool calibrated to the predictable BRD morbidity rate of specific cattle populations.

1

Defining High-Risk Cattle for Metaphylaxis

Metaphylaxis is economically justified when predicted BRD morbidity exceeds approximately 10–15% without treatment — the threshold at which metaphylaxis cost per head ($8–$18) is less than the avoided treatment and performance loss cost. High-risk cattle meeting this threshold include: cattle from multiple sources commingled at auction; unweaned or recently weaned lightweight calves from unknown preconditioning history; stocker calves traveling 6+ hours; cattle arriving in fall with visible stress signs (dehydration, weight loss during transit); and any group where the previous year's BRD morbidity exceeded 15%.

2

Choosing the Right Metaphylactic Product

Tulathromycin (Draxxin) and tildipirosin (Zuprevo) are the most commonly used metaphylaxis products due to their single-injection administration, long-acting residual tissue concentration, and broad spectrum against the primary BRD bacterial pathogens. Florfenicol is sometimes used when macrolide resistance is suspected in a specific risk group based on culture data or prior treatment failure patterns. Ceftiofur crystalline free acid is used in some low-risk metaphylaxis situations where shorter withdrawal time is desired. The specific product choice should be made with your veterinarian based on your operation's history, regional antimicrobial resistance patterns, and withdrawal time requirements.

3

Documenting Metaphylaxis for Antibiotic Stewardship

All metaphylaxis events must be documented under your written herd health protocol with veterinary oversight. Records must include: date, product name, dose per head, number of animals treated, lot or pen identification, withdrawal date calculation, and the veterinary protocol number authorizing the use. These records satisfy FDA VFD documentation requirements, support BQA antibiotic stewardship compliance, and provide the audit trail needed for any premium market program requiring documented health management. Electronic records linked to EID tag numbers are the gold standard for metaphylaxis documentation.

10. Vaccination Programs for BRD Prevention

A comprehensive BRD vaccination program is the most important investment in BRD prevention available to cattle producers at all production stages — from cow-calf producers vaccinating before weaning to feedlot operators vaccinating at arrival processing. Vaccination reduces the severity and duration of viral infections, reduces immunosuppression depth and duration, and reduces the probability that viral infection will progress to fatal bacterial pneumonia.

Vaccine Category Administration Timing Products Available Expected Benefit Key Considerations
Modified Live Virus (MLV) — 5-Way Respiratory 4–8 weeks before weaning or transport (allows immune development); booster at weaning Pyramid 5 Plus, Vista Once SQ, Bovi-Shield Gold, Bovilis Nasym Superior immune response vs killed vaccines; single dose often sufficient if given adequate time before stress Requires 2–3 weeks post-vaccination for adequate immune response; do NOT vaccinate within 2 weeks of transport (stress can suppress response)
Killed Virus — 5-Way Respiratory At weaning or arrival when MLV is contraindicated (pregnant cows, immunocompromised) Triangle 9, Bovilis MH+IBR, Express 5 Safer for pregnant cows and immune-compromised cattle; requires 2-dose series for primary response; lower efficacy than MLV in most trials Use when MLV is contraindicated; boost with MLV when appropriate
Mannheimia haemolytica Toxoid Primary: 4–6 weeks before weaning; Booster: at weaning Once PMH, Presponse SQ, Nuplura Specific antibody against M. haemolytica leucotoxin; reduces severity of M. haemolytica pneumonia; highly complementary with respiratory virus vaccines Requires 2-week minimum to develop adequate leucotoxin antibody; most impactful in preconditioning programs before the highest-risk period
IBR/BVD (MLV or KV) Part of 5-way respiratory protocol Included in all major 5-way BRD vaccines BVDV protection essential for preventing the most immunosuppressive pathogen; IBR booster reduces reactivation risk Ensure BVDV Type 1 and Type 2 coverage; consider single-antigen BVDV booster in high-risk scenarios
Intranasal IBR + PI3 At arrival in feedlot (can be given with other products) InForce 3, Nasym Rapid mucosal immunity onset (24–48 hours); can be given simultaneously with injectable MLV; useful for high-risk cattle already in transport stress Valuable when immunocompromise from transport prevents injectable MLV from working optimally; does not replace injectable MLV protection

11. BRD Impact and Treatment Outcome Chart

BRD Management Intervention Value Score — Economic Benefit per High-Risk Pen of 100 Cattle (Relative Scale 0–100)
Score represents relative economic benefit per pen of 100 high-risk receiving cattle. Based on USDA AMS data, KSU and Texas A&M feedlot health research, and veterinary economic analysis 2022–2026. Higher = greater economic return from intervention.
Preconditioning (VAC-45) Before Placement
96 — Reduces morbidity 30–50%; best cost:benefit of any intervention
MLV Respiratory + M. haemolytica Vaccine
88 — Foundation of prevention; 3–5x return on vaccine cost
Metaphylaxis on High-Risk Arrivals
82 — Positive ROI when morbidity risk exceeds 15%
Twice-Daily Pen Riding (Early Pull)
78 — Each day of treatment delay reduces cure rate by 10–15%
BVDV PI Testing + Removal
72 — High-value in commingled cattle; removes continuous shedder
Appropriate First-Line Antibiotic Selection
66 — Antibiotic class matching to pathogen profile improves cure rates 15–25%
Arrival Nutrition and Stress Reduction
58 — Water and palatable hay first; electrolytes in stressed cattle
Treatment Protocol Written with Vet (VCPR)
50 — Regulatory compliance + better decisions + premium market access

Frequently Asked Questions

What is the best antibiotic for treating BRD in cattle?
There is no universally "best" antibiotic for BRD — the best choice depends on the clinical severity, the pathogens most likely involved, your operation's antibiotic use history, withdrawal time constraints, and your veterinarian's written protocol. That said, long-acting macrolides — tulathromycin (Draxxin) and tildipirosin (Zuprevo) — are the most widely used first-line BRD treatments in the U.S. due to their single-injection convenience, long residual tissue concentration providing extended coverage during the high-risk period, and broad-spectrum activity against M. haemolytica, P. multocida, and H. somni. Florfenicol (Nuflor) is the preferred alternative when macrolide resistance is suspected or when Mycoplasma bovis is involved (florfenicol has some activity against Mycoplasma; macrolides are less reliable). Enrofloxacin (Baytril) is reserved for refractory BRD cases under veterinary oversight due to its fluoroquinolone class critical importance in human medicine — antimicrobial stewardship guidelines call for limiting this drug to cases where other options have failed or culture results indicate it is the appropriate choice. Never base antibiotic selection entirely on convenience or cost when BRD case fatality is on the line — consult your veterinarian and use culture and sensitivity data from your operation when available.
What is the difference between BRD and shipping fever?
Shipping fever is the historical common name for the most typical manifestation of Bovine Respiratory Disease — the acute pneumonia that develops in cattle 4–14 days after transport and commingling. The term reflects the original observation that cattle that have been "shipped" (transported) frequently develop high fever and respiratory illness shortly after arrival at a new location. BRD is the broader, more precise medical term that encompasses all manifestations of respiratory disease in cattle — including shipping fever, calf pneumonia (enzootic pneumonia), chronic BRD, and Mycoplasma bovis pneumonia — regardless of the specific trigger. All shipping fever is BRD, but not all BRD is shipping fever. The pathological process is the same: viral infection creates the immunosuppressive vulnerability window that allows bacterial pathogens (primarily M. haemolytica, P. multocida, and H. somni) to colonize the lower respiratory tract and establish pneumonia. The trigger may be transport stress (shipping fever), weaning stress, weather stress, or other immunosuppressive events — the resulting disease complex is the same regardless of what precipitated it.
How do you know if a cow has BRD?
The most reliable field identification approach for BRD in high-risk receiving cattle combines the DART scoring system with rectal temperature measurement. Observe each animal for: Depression (dull attitude, standing away from the group, not competing at the feed bunk); Appetite loss (not eating during feeding periods); Respiratory abnormalities (elevated breathing rate, flared nostrils, labored breathing); and Temperature (rectal temperature above 104°F is highly significant in a depressed animal during the first 21 days of placement). Ear droop — one or both ears positioned lower than normal — is one of the earliest and most reliable visual signs of systemic illness in cattle and should always prompt closer examination. A mucopurulent nasal discharge (thick, yellowish-green mucus visible on the muzzle) indicates active bacterial infection. The combination of fever (104°F+) + depression + reduced feed intake + nasal discharge in a high-risk animal during the first 14 days of placement is virtually diagnostic for BRD and warrants immediate antibiotic treatment under your written veterinary protocol. Lung auscultation with a stethoscope — crackles, wheezes, or areas of silent (consolidated) lung — provides the most definitive field confirmation of pneumonia. Train yourself to listen to 5–10 healthy lung sounds first so you can recognize the distinctly abnormal sounds of active BRD.
Can BRD be prevented without antibiotics?
Yes — a significant proportion of BRD cases are preventable through non-antibiotic strategies, and this should be the primary focus of every cattle health program. The most effective non-antibiotic BRD prevention strategies are: preconditioning calves before movement (45-day post-weaning program with viral respiratory and M. haemolytica vaccination reduces morbidity by 30–50%); comprehensive vaccination with modified live virus respiratory vaccines given 2–4 weeks before transport when the immune system can fully respond; BVDV PI testing and removal to eliminate the most powerful immunosuppressive pathogen reservoir from commingled groups; stress reduction through good handling, appropriate transport density and timing, and immediate access to water and palatable feed at arrival; and optimizing trace mineral status (selenium, zinc, copper, Vitamin E) in the cow herd and in receiving rations. These strategies together can reduce BRD morbidity in many high-risk groups from the 25–40% range to 8–12%, which may still require some antibiotic intervention but substantially reduces overall antibiotic use and associated cost. The goal of modern BRD management is not zero antibiotics — it is targeted, appropriate antibiotic use in genuinely sick animals combined with maximal non-antibiotic prevention that reduces the number of animals that need treatment.
What is the economic impact of BRD on a 100-head feedlot pen?
In a 100-head pen of high-risk receiving cattle with no BRD prevention program, typical industry morbidity rates run 25–40%. Using 30% as a representative figure (30 cattle treated), the economic impact calculation is: Direct treatment costs (antibiotic + labor): 30 animals × $55 average = $1,650. Performance penalty (reduced ADG during illness + chronic lung damage): 30 animals × $85 = $2,550. Death loss (2.5% typical, 2–3 animals): 2.5 × $1,200 average value = $3,000. Carcass quality penalty (dark cutters, condemnations in survivors): 30 cases × $40 average = $1,200. Total estimated BRD economic loss: approximately $8,400 per 100-head pen, or $84 per head placed. Compare this to the cost of a comprehensive prevention program: tulathromycin metaphylaxis ($15/head) + 5-way MLV vaccine ($8/head) = $23/head in prevention. If prevention reduces morbidity from 30% to 10% (a realistic expectation for good programs): 10 animals treated × $55 = $550 + 10 × $85 performance = $850 + 1 death × $1,200 = $1,200 + 10 × $40 carcass = $400. Total with prevention: $3,000. Savings from $8,400 to $3,000 = $5,400 per 100-head pen. Prevention cost: $2,300. Net return from prevention: $3,100 per 100-head pen, or $31/head. This is why BRD prevention programs consistently generate 3–5x their cost — the avoided losses are significantly greater than the prevention investment.

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