Endocarditis in Cattle: Heart Valve Infection Signs and Prognosis
- See your vet immediately if a cow has a new heart murmur, fever, weight loss, drop in milk production, fast heart rate, jugular pulses, or swelling under the chest or jaw.
- Endocarditis in cattle is usually a bacterial infection of a heart valve, most often linked to bacteria spreading through the bloodstream from another infection such as mastitis, metritis, pneumonia, navel infection, arthritis, abscesses, or liver disease.
- Diagnosis often needs a farm exam plus bloodwork, repeated blood cultures, and echocardiography. Early cases can be hard to confirm because signs may be vague at first.
- Prognosis is guarded to poor overall, especially once heart failure, severe valve damage, or widespread septic emboli are present. Some carefully selected cattle may improve with prolonged treatment directed by your vet.
What Is Endocarditis in Cattle?
Endocarditis in cattle is an infection and inflammation of the inner lining of the heart, usually affecting one of the valves. In adult cattle, it is the most common valvular heart disease reported. Bacteria circulating in the bloodstream can attach to a damaged or inflamed valve and form infected clumps called vegetations. These lesions interfere with normal blood flow and can damage the valve over time.
In cattle, the tricuspid valve is commonly involved, although other valves can be affected. When the right side of the heart is involved, infected material can break loose and travel to the lungs, causing septic emboli and breathing problems. In more advanced cases, the damaged valve can lead to congestive heart failure, fluid buildup, weakness, and a marked decline in production.
This condition often develops gradually. A cow may first show vague signs like poor appetite, intermittent fever, weight loss, or reduced milk output before obvious heart-related signs appear. Because early signs can look like many other diseases, prompt veterinary evaluation matters.
Symptoms of Endocarditis in Cattle
- New or changing heart murmur
- Fast heart rate that stays elevated
- Intermittent or persistent fever
- Weight loss or poor body condition
- Reduced milk production
- Jugular vein distension or visible jugular pulses
- Swelling under the jaw, brisket, or lower body from fluid buildup
- Exercise intolerance, weakness, or depression
- Rapid breathing, cough, or respiratory distress from septic lung emboli
- Lameness or painful swollen joints from septic spread
When to worry: see your vet immediately if a cow has a heart murmur with fever, a sudden drop in milk production, jugular pulses, brisket edema, breathing trouble, or unexplained weight loss. Endocarditis can be insidious early on, but once heart failure or septic emboli develop, the condition can worsen quickly. Even mild signs deserve attention if the cow also has a known source of infection such as mastitis, metritis, navel ill, pneumonia, or an abscess.
What Causes Endocarditis in Cattle?
Endocarditis in cattle is usually caused by bacteria entering the bloodstream and settling on a heart valve. The valve may already be irritated or damaged, which makes it easier for bacteria to attach. Reported bacteria in bovine cases include Trueperella pyogenes and Streptococcus species, though other organisms can be involved.
The infection often starts somewhere else in the body. Common source problems include mastitis, metritis, pneumonia, liver abscesses, arthritis, foot infections, umbilical infections in calves, traumatic reticuloperitonitis, and other chronic abscesses or septic conditions. In some cattle, no obvious original source is found by the time heart disease is recognized.
Risk tends to rise when a cow has a prolonged untreated infection, repeated bacteremia, or chronic inflammatory disease. Dairy cattle may first be noticed because of falling production, poor appetite, or failure to recover as expected from another infection. Finding and addressing the original source is an important part of your vet's workup.
How Is Endocarditis in Cattle Diagnosed?
Diagnosis starts with a careful farm exam. Your vet will listen for a murmur, assess heart rate and rhythm, check the jugular veins, look for edema, and evaluate the lungs and overall condition. Because the signs can overlap with traumatic reticulopericarditis, pneumonia, caudal vena cava problems, and other causes of heart failure, endocarditis is rarely diagnosed from one sign alone.
Common tests include a CBC and chemistry panel, plus blood cultures when feasible. Repeated blood cultures can help identify the bacteria involved, although prior antibiotic use may reduce the chance of a positive result. Echocardiography is one of the most useful tests because it may show vegetative lesions on the valve, valve insufficiency, chamber enlargement, or secondary heart changes.
Your vet may also recommend thoracic ultrasound, radiographs where practical, or additional testing to look for the original infection source. In published bovine data, blood culture and echocardiography are among the more sensitive antemortem tools, but diagnosis can still be challenging in living cattle. Sometimes the final confirmation is made only after death or at necropsy.
Treatment Options for Endocarditis in Cattle
Spectrum of Care means you have options. Here are treatment tiers at different price points.
Budget-Conscious Care
- Farm call and physical exam
- Focused assessment of heart murmur, fever, jugular pulses, edema, and respiratory signs
- Basic bloodwork if available
- Treatment of the suspected primary infection source when identified
- Empirical systemic antibiotics selected by your vet for food-animal use and withdrawal compliance
- Anti-inflammatory or supportive care when appropriate
- Discussion of welfare, production outlook, culling, or humane euthanasia if prognosis is poor
Recommended Standard Treatment
- Farm exam plus CBC and chemistry
- Repeated blood cultures when feasible before antibiotics
- On-farm or referral echocardiography
- Targeted antimicrobial plan directed by your vet, often for a prolonged course
- Supportive care for fever, dehydration, pain, or mild heart failure signs when appropriate
- Evaluation for the original infection source such as mastitis, metritis, pneumonia, abscess, or joint infection
- Recheck exam to assess appetite, temperature, murmur, heart rate, and production response
Advanced / Critical Care
- Referral-level hospitalization or intensive herd-side management
- Comprehensive echocardiography and serial monitoring
- Repeated cultures or additional diagnostics to identify septic emboli or concurrent disease
- Aggressive supportive care for dehydration, respiratory compromise, or congestive heart failure signs
- Longer and more closely supervised antimicrobial treatment plan within food-animal regulations
- Frequent reassessment of welfare, breeding value, milk withdrawal, slaughter withdrawal, and realistic prognosis
Cost estimates as of 2026-03. Actual costs vary by location, clinic, and individual case.
Questions to Ask Your Vet About Endocarditis in Cattle
Bring these questions to your vet appointment to get the most out of your visit.
- What findings make you most suspicious for endocarditis in this cow?
- Do you hear a murmur, and if so, what does its location suggest?
- What tests are most useful on this farm right now: bloodwork, blood cultures, ultrasound, or referral echocardiography?
- Is there a likely original infection source such as mastitis, metritis, pneumonia, a foot infection, or an abscess?
- Based on this cow's stage of disease, is treatment reasonable or is the prognosis too poor?
- If we treat, how long might therapy last and what signs would tell us the plan is working or failing?
- What milk and meat withdrawal considerations apply to the medications you are considering?
- At what point should we discuss humane euthanasia for welfare reasons?
How to Prevent Endocarditis in Cattle
Prevention focuses on reducing bloodstream infections. Work with your vet on strong mastitis control, clean calving management, prompt treatment of metritis, careful navel care in calves, and early attention to pneumonia, lameness, foot infections, and abscesses. Chronic untreated infections give bacteria more chances to seed the heart.
Good hygiene during injections, catheter use, dehorning, castration, and other procedures also matters. Clean equipment, proper restraint, and following labeled or veterinary-directed protocols can lower the risk of introducing bacteria. In dairy and beef systems alike, routine observation helps catch sick cattle before a localized infection becomes systemic.
If a cow has persistent fever, poor thrift, or a slow recovery after another infection, ask your vet whether a heart exam is warranted. Endocarditis cannot always be prevented, but fast recognition and treatment of primary infections is the most practical way to reduce risk across the herd.