Bovine Heart Anatomy and Auscultation Landmarks

By Dr. Zubair Khalid, DVM, MS, PhD · 2026-08-11

Key Takeaways

• The bovine heart is centrally located within the thorax, extending from the 3rd to 6th intercostal spaces, with the apex near the sternum at the 5th intercostal space; the right hemithorax offers the primary auscultation window due to the cardiac notch.
• Auscultation landmarks for specific valves are: tricuspid (right, 3rd-4th ICS), pulmonic (left, 3rd ICS), mitral (left, 4th ICS), and aortic (left, 2nd-3rd ICS, dorsal).
• Traumatic reticulopericarditis, a common condition, presents with characteristic auscultatory findings including friction rubs, muffled heart sounds, and potentially splashing sounds due to gas accumulation, necessitating echocardiography for definitive diagnosis.
• Normal resting heart rates are 60-80 bpm in adults and 80-120 bpm in calves; tachycardia above 100 bpm in adults can obscure normal heart sounds and gallop rhythms.
• Murmurs are classified by timing, location, intensity, and quality; systolic murmurs are common, often due to atrioventricular valve regurgitation or ventricular septal defects, while diastolic murmurs suggest valve insufficiency.
• Early detection of cardiac disease, often indicated by tachycardia, abnormal heart sounds, jugular distention, and ventral edema, is critical as prognosis is poor once congestive heart failure develops.

This article provides a practical guide to the gross anatomy of the bovine heart and the correct placement of a stethoscope for cardiac auscultation in cattle. It is written for veterinary students and practitioners who require a working knowledge of thoracic topography, cardiac chamber orientation, valve positions, and the acoustic windows that permit reliable assessment of heart sounds in the field. The content assumes familiarity with general mammalian cardiovascular anatomy and clinical examination technique.

Cardiac disease in cattle is frequently identified only after signs of congestive heart failure have appeared, and the prognosis at that stage is often poor. Tachycardia, abnormal heart sounds, jugular distention, and ventral edema are the cardinal findings, and auscultation remains the most accessible diagnostic step in a field setting Antemortem cardiac diagnostic approaches in cattle. A thorough understanding of bovine thoracic anatomy and disciplined stethoscope placement directly determines whether auscultation yields useful information or misleading noise. This article answers the practical question of where to listen, what to expect, and how to interpret the sounds that reach the stethoscope.

At a Glance

Thoracic Topography and Heart Position

The bovine heart occupies a more upright and centrally positioned location within the thorax than the hearts of small animals. It lies within the mediastinum, extending from the third to the sixth intercostal space, with the base directed dorsocranially and the apex positioned ventrally near the sternum. The heart is enclosed by the pericardium, which in cattle is a relatively tough fibrous sac that attaches to the sternum via the sternopericardiac ligament. This ligamentous attachment has clinical significance because it predisposes cattle to traumatic pericarditis when penetrating foreign bodies migrate from the reticulum through the diaphragm and into the pericardial sac.

The cranial border of the heart is overlapped by the cranial lung lobes, while the caudal border is related to the caudal lung lobes. The cardiac notch of the right lung is larger than that of the left, which means the right hemithorax offers a more direct acoustic window to the heart in cattle. This anatomical arrangement is the reason right-sided auscultation is often more productive in bovine patients than in other species. The heart's long axis is oriented obliquely, running from the craniodorsal base to the caudoventral apex, and this orientation must be understood before the stethoscope is placed.

Cardiac Chamber Orientation and Valve Positions

The bovine heart has four chambers arranged in the standard mammalian pattern, but the spatial relationships differ from those in dogs and cats. The right atrium and right ventricle lie cranially and ventrally, while the left atrium and left ventricle lie caudally and dorsally. The interventricular septum runs obliquely, and the apex of the heart is formed almost entirely by the left ventricle, which gives the bovine heart its characteriztic conical shape.

The right atrioventricular valve, the tricuspid valve, is located on the right side of the heart at the level of the 3rd to 4th intercostal space. The pulmonic valve sits at the base of the pulmonary trunk, cranial and slightly dorsal to the tricuspid valve. On the left side, the mitral valve lies at the 4th intercostal space, and the aortic valve is positioned dorsal and cranial to the mitral valve, near the base of the heart. The ascending aorta and brachiocephalic artery arise from the aortic arch and pass cranially, and individual variation in the branching pattern of these vessels is recognized Anatomy of the bovine ascending aorta and brachiocephalic artery. This variability is relevant when interpreting imaging studies and when planning surgical or interventional procedures.

The Pericardium and Its Clinical Significance

The pericardium in cattle is a double-layered sac consisting of an outer fibrous layer and an inner serous layer. The serous layer reflects over the heart as the epicardium, and the small volume of pericardial fluid between the layers permits friction-free movement during the cardiac cycle. The fibrous pericardium is attached to the sternum, the diaphragm, and the great vessels, anchoring the heart within the thorax.

Traumatic reticulopericarditis is a common and serious condition in cattle, particularly in adult dairy animals. Foreign bodies that penetrate the reticulum can migrate through the diaphragm and into the pericardial sac, introducing infection and gas. The resulting pericarditis produces characteriztic auscultatory findings, including muffled heart sounds, a pericardial friction rub in the early stages, and sometimes a splashing sound if gas and fluid accumulate. Echocardiography is the definitive diagnostic tool for this condition, and it can also detect congenital defects such as ventricular septal defects Antemortem cardiac diagnostic approaches in cattle. The prognosis for traumatic pericarditis is guarded to poor, and early recognition through careful auscultation improves the chance of timely intervention.

Auscultation Windows and Stethoscope Placement

The stethoscope should be placed on the thoracic wall where the heart is closest to the surface and where overlying lung tissue is thinnest. In cattle, the primary auscultation window is on the right hemithorax, over the 3rd and 4th intercostal spaces, in the lower third of the thorax just dorsal to the olecranon. The right cardiac notch allows the heart to contact the thoracic wall directly, providing a clear acoustic path for the stethoscope.

On the left side, the heart is partially covered by the left lung, and the acoustic window is smaller. The left-sided window lies over the 4th intercostal space, at the level of the shoulder joint, where the mitral valve is best heard. The aortic valve is auscultated slightly more dorsally and cranially, near the 3rd intercostal space. The tricuspid valve is best heard on the right side at the 3rd intercostal space, and the pulmonic valve is heard on the left at the 3rd intercostal space, dorsal to the tricuspid area.

The examiner should use a stethoscope with a large diaphragm and a bell, and the animal should be restrained in a calm manner to minimize movement and respiratory noise. The hair coat should be dry and free of debris, and firm pressure should be applied to the chest piece to ensure good skin contact. Auscultation should be performed systematically, moving from the right to the left side and from the base to the apex of the heart, with attention to the rate, rhythm, and character of the heart sounds.

Normal Heart Sounds and Their Generation

The bovine heart produces audible vibrations that correspond to mechanical events in the cardiac cycle. The first heart sound (S1) marks closure of the atrioventricular valves at the onset of ventricular systole. It is dull, prolonged, and best heard over the mitral and tricuspid valve areas. The second heart sound (S2) results from closure of the aortic and pulmonary valves at the end of systole. It is shorter, sharper, and of higher frequency than S1. In cattle, S2 is typically louder than S1 over the left base because of the large aortic root and the relatively superficial position of the great vessels.

Physiological splitting of S2 can occur during inspiration, although this is less prominent in cattle than in small animals because of the comparatively slower respiratory rate. Third (S3) and fourth (S4) heart sounds are normally inaudible in adult cattle. Their presence, particularly a distinct S3 or a summation gallop, indicates ventricular dilation, myocardial failure, or restrictive pericardial disease. Tachycardia in cattle, defined as a heart rate above 100 beats per minute in adults, often obscures the distinction between S1 and S2 and makes gallop rhythms difficult to characterize. Antemortem cardiac diagnostic approaches in cattle emphasize that abnormal heart sounds are frequently the first detectable abnormality in cattle with developing cardiac disease, often preceding visible jugular distention or ventral edema.

Systematic Auscultation Protocol

Auscultation should follow a fixed sequence so that no valve area is overlooked. Begin at the left fourth intercostal space, one hand's width above the olecranon, and listen for the mitral component of S1. Move cranially to the left third intercostal space for the pulmonary valve, then to the left second or third intercostal space at the level of the shoulder joint for the aortic valve. Finally, cross to the right side and auscultate the third and fourth intercostal spaces for the tricuspid valve. Each site should be assessed for at least 15 to 30 seconds, and the heart rate should be counted over a full minute because arrhythmias in cattle are frequently intermittent.

The stethoscope chest piece should be held firmly against the skin with minimal hair interference. In long-haired breeds, wetting the hair coat or parting it along the intercostal space improves acoustic transmission. The diaphragm is preferred for detecting high-frequency murmurs and the bell for low-frequency gallops and S3 sounds, although in practice the diaphragm alone will identify most clinically significant abnormalities. Compare the intensity of heart sounds between the left and right hemithorax. Asymmetry, particularly muffling on one side with normal sounds on the other, suggests a unilateral thoracic effusion, a mass, or pericardial pathology.

Murmur Classification and Interpretation

Murmurs in cattle are classified by timing, location, intensity, and quality. Systolic murmurs are the most common and are typically caused by atrioventricular valve regurgitation or ventricular septal defects. A holosystolic murmur loudest over the left apex with radiation toward the axilla is characteriztic of mitral regurgitation. A harsh, band-shaped systolic murmur best heard over the right hemithorax raises suspicion for a ventricular septal defect, a congenital lesion that echocardiography can confirm. Antemortem cardiac diagnostic approaches in cattle note that ventricular septal defects are among the congenital abnormalities most readily identified with ultrasound in calves.

Diastolic murmurs are uncommon in cattle. When present, they usually indicate aortic or pulmonary valve insufficiency, often secondary to endocarditis. The murmur of aortic regurgitation is decrescendo, begins immediately after S2, and is best heard over the left base. Continuous murmurs are rare and suggest a patent ductus arteriosus or an arteriovenous fistula.

Murmur intensity is graded on a scale of 1 to 6. Grade 1 murmurs are barely audible, grade 2 are soft but readily detected, grade 3 are moderately loud without a palpable thrill, grade 4 are loud with a palpable thrill, grade 5 are very loud but require the stethoscope to be off the chest wall to be heard, and grade 6 are audible with the stethoscope lifted from the skin. A palpable thrill over the left thorax is a reliable indicator of a significant murmur and should prompt a guarded prognosis. Functional murmurs, often called flow murmurs, occur in anemic calves, in cattle with fever, and during late pregnancy when cardiac output rises. These are typically soft, early systolic, and localized to the left base. They disappear when the underlying condition resolves.

Pericardial Disease and Its Auscultatory Signs

Pericarditis in cattle is most frequently caused by traumatic reticulopericarditis, in which a penetrating foreign body from the reticulum migrates through the diaphragm into the pericardial sac. The auscultatory findings evolve with the stage of disease. Early fibrinous pericarditis produces a friction rub, a superficial, scratchy sound synchronous with cardiac motion. As fluid and gas accumulate, the rub disappears and is replaced by muffled heart sounds. If gas-forming organizms are present, a splashing or tinkling sound, termed bruit de moulin, may be heard over the cardiac area. This finding is virtually pathognomonic for septic pericarditis with gas production.

Muffled heart sounds in a cow with jugular distention, ventral edema, and tachycardia should always raise suspicion for pericardial effusion or pericarditis. However, muffling can also result from pleural effusion, pulmonary consolidation, or a large mediastinal mass. Echocardiography is the definitive diagnostic tool and can distinguish pericardial fluid from pleural fluid and from pericardial fat. Antemortem cardiac diagnostic approaches in cattle describe echocardiography as essential for confirming pericardial disease and for guiding the decision between medical management and surgical drainage.

Documentation and Monitoring

Auscultation findings should be recorded systematically to allow comparison over time. Document the heart rate, rhythm, the intensity of S1 and S2 at each valve area, the presence and grade of any murmur, and the character of any adventitious sounds. Include the respiratory rate and the presence or absence of a jugular pulse, because these findings together determine whether cardiac disease is likely and whether it is right-sided, left-sided, or biventricular.

Serial auscultation is particularly valuable in monitoring response to treatment. A cow with traumatic pericarditis that improves on medical therapy should show progressive resolution of tachycardia, a return of normal heart sound intensity, and disappearance of the friction rub or splashing sounds. Worsening muffling, increasing heart rate, or the development of a gallop rhythm indicates progression of disease and a need to revisit the diagnosis. In calves with suspected congenital heart disease, auscultation should be repeated at intervals because some murmurs, particularly those from a patent ductus arteriosus, may close spontaneously in the first weeks of life.

Documentation should also note the animal's signalment and production status, because these influence interpretation. A high-producing dairy cow in early lactation may have a soft functional murmur and mild tachycardia that resolve with adequate energy balance. A beef cow in late gestation may show jugular distention from abdominal pressure alone, without cardiac disease. The auscultator must integrate the cardiac examination with the complete physical examination and, where available, with echocardiographic findings before assigning a diagnosis or prognosis. Antemortem cardiac diagnostic approaches in cattle stress that accurate diagnosis depends on understanding bovine anatomy and proper technique, and that auscultation remains the most valuable screening tool in field settings where advanced imaging is unavailable.

Recognized Complications and Early Detection

Bovine cardiac disease is frequently identified only after congestive heart failure signs have developed, and the prognosis at that stage is poor. Antemortem cardiac diagnostic approaches in cattle emphasize that tachycardia, abnormal heart sounds, jugular distention, and ventral edema are the clinical hallmarks that should trigger a complete cardiac evaluation. Early detection depends on recognizing these signs before they progress to recumbency or respiratory distress.

Pericarditis, most commonly secondary to traumatic reticulopericarditis, produces a characteriztic auscultatory finding: a friction rub in the early fibrinous stage, followed by muffled heart sounds with a "washing machine" splashing murmur once fluid and gas accumulate. Serial auscultation at 12 to 24 hour intervals can capture this transition. A sudden worsening of tachycardia with a drop in rumen motility and the development of brisket edema should raise suspicion of cardiac tamponade physiology.

Endocarditis, usually vegetative and affecting the right atrioventricular valve in cattle, presents with a regurgitant murmur, intermittent pyrexia, and shifting lameness. Blood culture remains the definitive diagnostic step, but echocardiography can identify vegetative lesions when available. Antemortem cardiac diagnostic approaches in cattle note that echocardiography also detects congenital defects such as ventricular septal defects, which may be incidental findings in otherwise productive animals.

Congestive heart failure from high-altitude disease or brisket disease warrants pulmonary artery pressure measurement to confirm the diagnosis and stage severity. This requires specialised equipment and expertise that may not be available in ambulatory practice.

Common Errors and Corrective Actions

The most frequent error in bovine cardiac auscultation is incorrect stethoscope placement. The bovine heart lies more caudally and ventrally than students expect, with the apex near the sternum at the level of the fifth to sixth intercostal space. Placing the bell over the triceps muscle or too far cranially produces muffled sounds that are misinterpreted as cardiac disease. Corrective action: palpate the point of the elbow, then move one intercostal space caudally and place the stethoscope directly behind the triceps, high on the thoracic wall for the base and low near the sternum for the apex.

A second common error is failing to distinguish respiratory sounds from cardiac murmurs. Cattle have pronounced bronchovesicular sounds, particularly in the cranioventral lung fields, and these can obscure or mimic cardiac murmurs. Pausing the examination during expiration or briefly holding the animal's respiration by occluding the nostrils clarifies the distinction.

Third, students frequently misinterpret sinus arrhythmia as a pathologic dysrhythmia. Bovine heart rate varies with respiration, and this is a normal finding. True pathologic bradycardia or tachycardia should be assessed against reference ranges for the animal's age and production status.

Fourth, the jugular pulse is often assessed incorrectly. A visible jugular pulse in the lower third of the neck is normal, but a pulse that extends to the upper third or persists after digital occlusion of the jugular vein indicates right-sided heart failure.

Limitations of Current Evidence

The evidence base for bovine cardiac auscultation is largely descriptive and derived from clinical experience instead of controlled trials. The MSD Veterinary Manual provides standard reference values for heart rate and auscultatory findings, but these are drawn from mixed breed and production populations and may not apply to all cattle types. Expert opinion differs on the clinical significance of soft murmurs in adult cattle, particularly in dairy cows where high cardiac output during lactation can produce physiologic flow murmurs.

The bovine ascending aorta and brachiocephalic trunk show considerable anatomic variation, and studies of total artificial heart implantation have documented vascular anomalies that complicate surgical approaches. This variability has implications for interpreting thoracic radiographs and echocardiograms, where apparent aortic dilation may be a normal variant instead of pathology.

Virtual implantation techniques developed for transitioning device testing from porcine to bovine models have improved understanding of bovine thoracic anatomy, but these studies focus on surgical applications instead of clinical auscultation. The correlation between auscultatory findings and echocardiographic or postmortem confirmation in cattle remains incompletely characterized.

Referral and Escalation Criteria

Referral for echocardiography or specialist consultation is warranted when a murmur is loud, diastolic, or associated with clinical signs such as tachycardia, jugular distention, or exercise intolerance. Congenital heart disease suspected in a neonate or young stock animal should be confirmed by echocardiography before making breeding or culling decisions, as antemortem cardiac diagnostic approaches in cattle note that accurate diagnosis enables timely management and prognosis.

Laboratory involvement is indicated for suspected endocarditis, where blood cultures and serial hematology can support the diagnosis, and for suspected myocardial disease where cardiac biomarker measurement may be considered. Pulmonary artery pressure measurement requires referral to a facility with the appropriate equipment.

Regulatory reporting obligations vary by jurisdiction. Suspicion of notifiable diseases that can present with cardiac signs, such as certain systemic infections, should be checked against WOAH terrestrial animal health standards and local veterinary authority requirements. AVMA practice resources provide guidance on professional obligations regarding zoonotic disease communication and record keeping.

When congestive heart failure is advanced and treatment options are limited, discussion of humane euthanasia is appropriate. The poor prognosis associated with late-stage bovine cardiac disease should be communicated clearly to the owner, with emphasis on welfare considerations and the limited likelihood of recovery.

Frequently Asked Questions

How should I adapt my auscultation approach when working in a chute or head gate with limited access to the left thoracic wall?

Position the animal with its head restrained and body shifted slightly to the right in the chute, which widens the intercostal spaces on the left side. If the left thoracic window is inaccessible, move to the right hemithorax. The right fourth to sixth intercostal spaces transmit tricuspid and pulmonic valve sounds with acceptable fidelity, though the right-sided window is narrower and deeper than the left. Use a large-diaphragm stethoscope head and apply firm, steady pressure to displace the heavy triceps and cutaneous musculature. For fractious animals, auscultate during quiet rumination instead of after handling, since stress-induced tachycardia and tachypnea obscure murmurs and alter sound intensity. Antemortem cardiac diagnostic approaches in cattle emphasize that auscultation remains the most practical field screening tool despite these positional constraints.

What can I do when a high-quality stethoscope is unavailable or damaged?

A standard human adult stethoscope with a large chest piece is adequate for most bovine cardiac assessments. The key limitation is acoustic insulation, not the bell-versus-diaphragm distinction. Place the chest piece directly on clipped skin, not over hair, and use both hands to seal the rim completely. If the tubing is cracked, replace it instead of taping, since air leaks attenuate low-frequency sounds disproportionately. In emergency settings, a rolled cardboard tube pressed firmly against the thoracic wall can transmit S1 and S2, but it will not resolve murmurs or pericardial friction rubs reliably. Document the equipment limitation in the record and note that subtle findings may have been missed. The MSD Veterinary Manual advises that auscultatory findings should always be interpreted alongside heart rate, jugular filling, and mucous membrane color.

How do I distinguish a clinically significant murmur from a functional or flow murmur in a growing calf?

Functional murmurs in calves under six months are typically systolic, soft, and localized to the left heart base, with no associated tachycardia, jugular distention, or growth retardation. Pathologic murmurs are louder than grade 3 of 6, radiate widely, and persist when heart rate normalizes. A ventricular septal defect produces a harsh pansystolic murmur at the right cranial thorax, whereas a functional murmur is best heard at the left base and varies with respiratory phase. Serial re-examination is the most useful discriminator: functional murmurs diminish as the calf grows, while structural lesions remain stable or worsen. Echocardiography is the definitive tool when doubt persists, and antemortem cardiac diagnostic approaches in cattle note that congenital defects such as ventricular septal defects are reliably detected with ultrasound in field settings.

What findings on cardiac auscultation should prompt immediate referral or euthanasia consideration?

A heart rate above 120 beats per minute in an adult cow at rest, combined with a gallop rhythm or muffled heart sounds, indicates advanced cardiac compromise. Jugular distention that persists after the animal lowers its head, ventral edema extending to the brisket, and a palpable precordial thrill all suggest congestive heart failure. A pericardial friction rub early in the disease course, followed by muffled sounds with a "washing machine" splashing murmur, points to traumatic pericarditis with gas-forming infection. These animals deteriorate rapidly and carry a grave prognosis. Discuss the findings with the owner and present options for diagnostic confirmation, salvage, or humane euthanasia. WOAH terrestrial animal health standards address the welfare obligations that apply when an animal cannot be treated effectively.

How should I document auscultatory findings so another clinician can interpret them later?

Record the heart rate, rhythm regularity, and the location, timing, grade, and quality of any murmur using a standardized format. Specify the intercostal space and the third of the thoracic height where the finding was loudest. Use a grading scale from 1 to 6 and state whether a thrill was palpable. Describe the character of S1 and S2 separately, and note any splitting, accentuation, or muffling. Include the animal's body condition, age, and recent handling history, since these affect heart rate and sound transmission. Note the stethoscope type and whether the skin was clipped. The AVMA practice resources recommend that clinical records support continuity of care and defensible decision-making, so include a plan for recheck timing and any referral discussions.

How do I explain cardiac findings to a producer who needs to make a financial decision?

Lead with the prognosis and the timeline, not the anatomy. State clearly whether the animal is in heart failure, whether treatment is feasible, and what the expected survival is with and without intervention. Use the auscultatory findings as supporting evidence: a loud murmur with a thrill means structural disease, while a soft murmur in a calf may resolve. Explain that blood tests and ultrasound can refine the diagnosis but add cost, and that in many cases the physical findings are sufficient to decide. For breeding stock, mention that some cardiac defects are heritable and that affected animals should not be retained. The NCBI Bookshelf collection provides background on comparative cardiac physiology that can help frame the discussion in terms producers understand, such as comparing the failing heart to a worn pump.

Related Clinical & Scientific Guides

• Canine Respiratory System: Anatomy and Physiology
• Comparative Anatomy of the Mammalian Kidney
• Feline Cardiopulmonary Physiology: Heart-Lung Interactions

References and Further Reading

• Antemortem Cardiac Diagnostic Approaches in Cattle.. 2026.
• Virtual implantations to transition from porcine to bovine animal models for a total artificial heart.. 2020.
• Anatomy of the bovine ascending aorta and brachiocephalic artery found unfavorable for total artificial heart implant.. 2015.
• NCBI Bookshelf: Veterinary and Comparative Biomedical Sciences. NCBI Bookshelf.
• MSD Veterinary Manual, Professional Edition. MSD Veterinary Manual.
• American Veterinary Medical Association Practice Resources. American Veterinary Medical Association.
• WOAH Terrestrial Animal Health Code. WOAH.

Related Articles

• Comparative Anatomy of the Mammalian Heart
• Bovine Female Reproductive Anatomy and Physiology
• Feline Cardiovascular Anatomy and Physiology
• Bovine Mammary Gland Anatomy and Lactation Physiology
• Bovine Musculoskeletal Anatomy: Axial Skeleton and Joints

This article is educational professional reference material for veterinary audiences. It is not a substitute for veterinary diagnosis, individual clinical judgment, current product labeling, or applicable regulatory requirements.