Bovine Respiratory Disease Complex in Cattle: Signs, Causes, and Treatment
- See your vet immediately if a calf or adult cow has fever, cough, nasal discharge, fast breathing, droopy ears, depression, or reduced feed intake.
- Bovine respiratory disease complex, often called BRD or shipping fever, is a multifactorial pneumonia syndrome linked to stress, viruses, bacteria, and management factors.
- Early treatment matters. Cattle treated in the first stage of illness usually have a better chance of recovery and less long-term lung damage.
- Typical on-farm cost range for an uncomplicated first case is about $40-$150 per animal for exam, temperature check, labeled antimicrobial, and supportive care. More severe cases, repeat treatments, diagnostics, or losses can raise the cost range to $150-$600+ per animal.
What Is Bovine Respiratory Disease Complex in Cattle?
Bovine respiratory disease complex, often shortened to BRD, is a common respiratory illness of cattle. You may also hear it called shipping fever pneumonia or undifferentiated fever. It is not one single infection. Instead, it is a disease complex that develops when stress, immune suppression, viruses, bacteria, and environmental conditions combine to overwhelm the lungs.
BRD is especially common in recently weaned, transported, commingled, or newly arrived feedlot calves, but dairy calves and adult cattle can also be affected. In North American beef systems, it remains one of the most important causes of sickness, death, reduced weight gain, and treatment costs.
In many cases, a viral infection or major stress event damages the normal defenses of the upper airway. Bacteria that may already be present in the nose and throat can then move deeper into the lungs and cause bronchopneumonia. That is why BRD often appears after weaning, hauling, weather swings, crowding, or mixing cattle from multiple sources.
Because BRD can worsen quickly, early recognition is critical. A calf that only looks a little dull in the morning may be breathing hard by evening. Prompt evaluation by your vet helps match treatment intensity to the animal, the group, and the production setting.
Symptoms of Bovine Respiratory Disease Complex in Cattle
- Fever, often over 103.5°F
- Depression, lethargy, or standing apart from the group
- Reduced appetite or slower feed intake
- Cough, especially spontaneous coughing
- Nasal discharge that may start watery and become cloudy or mucopurulent
- Increased respiratory rate or noticeable effort to breathe
- Droopy ears, head tilt, or dull facial expression
- Eye discharge
- Open-mouth breathing, marked dyspnea, or inability to rise
- Sudden death in severe outbreak situations
Early BRD signs can be subtle. Affected cattle may look quiet, lag behind the group, keep their head low, or eat less before obvious coughing starts. Fever, nasal discharge, cough, ear droop, and faster breathing are common field signs used in respiratory scoring systems.
See your vet immediately if breathing becomes labored, the animal is open-mouth breathing, will not rise, stops eating, or multiple cattle in the group are affected. Severe cases can decline fast, and delayed treatment increases the risk of chronic lung damage, poor growth, and death.
What Causes Bovine Respiratory Disease Complex in Cattle?
BRD develops from a combination of infectious and noninfectious factors. Common bacterial pathogens include Mannheimia haemolytica, Pasteurella multocida, Histophilus somni, and Mycoplasma bovis. Important viral contributors include bovine herpesvirus 1, parainfluenza-3 virus, bovine viral diarrhea virus, and bovine respiratory syncytial virus. These viruses can weaken airway defenses and make secondary bacterial pneumonia more likely.
Stress is a major trigger. Weaning, long-distance transport, dehydration, feed changes, crowding, dust, poor ventilation, weather extremes, and mixing cattle from different sources all increase risk. Recently weaned calves and newly received feedlot cattle are especially vulnerable because several stressors often happen at the same time.
Management and immunity also matter. In calves, poor transfer of passive immunity, inadequate colostrum management, underfeeding, and housing problems can raise BRD risk. In older cattle, biosecurity gaps, poor air quality, and repeated pen moves can contribute.
This is why BRD prevention and treatment are rarely one-size-fits-all. Your vet may look at the individual animal, the group pattern, and the farm or feedlot setup before recommending a plan.
How Is Bovine Respiratory Disease Complex in Cattle Diagnosed?
Your vet usually starts with history and a hands-on exam. Important clues include recent weaning, hauling, commingling, weather stress, vaccination history, and how many animals are affected. On exam, your vet may check rectal temperature, attitude, appetite, nasal and eye discharge, cough, ear position, and breathing effort. In many field settings, these signs are combined into a respiratory score to help identify sick cattle early.
Diagnosis is often clinical at first, especially when treatment decisions need to be made quickly. A rectal temperature above about 103.5°F together with depression, cough, and nasal discharge can support a working diagnosis of BRD. Your vet may also listen to the lungs and assess hydration and rumen fill.
When cases are severe, recurrent, not responding as expected, or affecting many animals, additional testing can help. Depending on the situation, your vet may recommend nasal or nasopharyngeal swabs, transtracheal wash, bronchoalveolar lavage, PCR testing for viral agents, culture, or necropsy of animals that died. Cornell's current bovine respiratory PCR options list transtracheal wash or bronchoalveolar lavage fluid as preferred samples for some respiratory panels.
These tests do not replace a farm-level assessment. They work best when paired with treatment records, timing of illness, and a review of ventilation, stocking density, nutrition, and handling practices.
Treatment Options for Bovine Respiratory Disease Complex in Cattle
Spectrum of Care means you have options. Here are treatment tiers at different price points.
Budget-Conscious Care
- Prompt on-farm exam and rectal temperature check
- Early pull and isolation from the main group when practical
- One labeled first-line antimicrobial selected by your vet
- Basic supportive care such as easy access to water, palatable feed, shade or wind protection, and reduced handling stress
- Simple treatment records and recheck plan in 24-48 hours
Recommended Standard Treatment
- Veterinary-guided treatment protocol for the individual or group
- Labeled antimicrobial therapy with dose and route matched to weight and production class
- Anti-inflammatory or fever-control medication when appropriate and legal for the case
- Hydration support and nursing care
- Defined pull criteria, retreatment intervals, and monitoring of appetite, temperature, and breathing
- Review of group risk factors such as ventilation, stocking density, transport stress, and vaccination timing
Advanced / Critical Care
- Full veterinary reassessment for severe, relapsing, or outbreak cases
- Diagnostics such as PCR, culture, transtracheal wash or bronchoalveolar lavage, and necropsy review when indicated
- Second-line or targeted antimicrobial changes based on response or test results
- More intensive supportive care, including fluids and close monitoring
- Management investigation for ventilation, biosecurity, commingling, passive transfer, and handling stress
- Decision-making support for chronic cases, culling, or outbreak control plans
Cost estimates as of 2026-03. Actual costs vary by location, clinic, and individual case.
Questions to Ask Your Vet About Bovine Respiratory Disease Complex in Cattle
Bring these questions to your vet appointment to get the most out of your visit.
- Based on this animal's signs and temperature, does this look like early BRD or a more advanced pneumonia case?
- Which pathogens are most likely in our herd or feedlot, and would testing change treatment or prevention decisions?
- What treatment protocol fits this animal's age, weight, production class, and withdrawal requirements?
- When should we recheck temperature, appetite, and breathing, and what signs mean the first treatment is not working?
- Should this animal be isolated, and what group-level monitoring should we start right away?
- Are our weaning, transport, commingling, or pen-move practices increasing BRD risk?
- Does our vaccination and preconditioning program need to change before the next high-risk period?
- When do you recommend necropsy, PCR, or airway sampling in our operation?
How to Prevent Bovine Respiratory Disease Complex in Cattle
BRD prevention works best when it addresses multiple risk factors at once. Vaccination programs, preconditioning, biosecurity, and early detection are core tools. Merck Veterinary Manual notes that prevention and control rely on vaccination, preconditioning, identifying subclinically affected animals, and biosecurity.
Stress reduction is a major part of prevention. Work with your vet to review weaning timing, transport plans, commingling, stocking density, pen moves, and handling methods. Cornell extension materials from 2025 also emphasize minimizing stress, improving ventilation, reducing overcrowding, and using low-stress handling.
For calves, strong colostrum management and passive transfer matter. Good nutrition, clean housing, dry bedding, and steady feeding programs support immune function. Avoid abrupt diet changes when possible, and pay attention to air quality, drafts, humidity, and dust.
If BRD keeps recurring, ask your vet for a herd-level review rather than focusing only on individual treatments. Looking at records, necropsy findings, vaccination timing, and facility design often reveals practical changes that lower future disease pressure.