Bovine Flashcards
You are called out to a dairy herd that has recently been experiencing reproductive problems. The cows were all acquired 1 year ago from an unknown source and have no known vaccinations or tattoos. The dairyman reports that several cows have had late abortions (6-7 months gestation) and weak or stillborn calves in the past year and he’s never had this problem before. Several of the cows that had abortions developed placental retention and/or metritis.
None of the younger pre-pubescent heifers are displaying any clinical signs. You perform a necropsy on two recently aborted fetuses and find lung consolidation in one but no other obvious abnormalities. Which of the following should you recommend?
- Serologic testing for Neospora
- Test for Trichomoniasis
- Test for Campylobacter fetus subsp venerealis
- Serologic testing for Brucellosis
Answer: Serologic testing for Brucellosis
Explanation
You should be most suspicious of Brucellosis based on the assortment of signs (abortions, retained placenta, metritis and lack of signs in younger animals), the timing of abortions (last half of pregnancy), and the relatively normal appearance of the examined fetuses. Plus the cattle are not tattooed as they should be if they were given calfhood brucella vaccine.
Tritrichomonas fetus abortions usually occur in the first half of gestation but do have placentitis and pneumonia in the fetus as does Brucella. Campylobacter fetus subsp venerealis usually causes early embryonic death. Neospora abortions are usually mid gestation and cause necrosis of the cotyledons, with fetal lesions including myocarditis, hepatitis, myositis and encephalitis.
When performing a necropsy on a cow, you find multiple abnormalities including abomasal ulcers, interstitial pneumonia, pericardial effusion, and mastitis. You also see that the liver has a brown- (tan) and red-mottled lobular pattern described as a nutmeg liver. Which of these conditions in the cow could lead to the necropsy findings in the liver?
- Pericardial effusion
- Abomasal ulcers
- Interstitial pneumonia
- Mastitis
Answer: Pericardial effusion.
Explanation
The appearance of a nutmeg liver occurs because there are red central veins and sinusoids between tan areas of swollen hepatocytes. This occurs with right sided heart failure from passive congestion of the sinusoids of hepatocellular hypoxia. Pericardial effusion causes right sided heart failure and is the cause of the liver’s appearance.
You perform a joint tap on a swollen carpus of this bull in the picture and obtain the following results: total protein 4.7 g/dl, total nucleated cell count 26,900/ul, 84% neutrophils. What is your interpretation of these results?
- Normal
- Unlikely to be infected
- Likely to be immune mediated joint disease
- Likely infected
Answer: Likely infected.
Explanation
The correct answer is likely infected.
Guidelines for an infected joint are as follows:
- total protein greater than 4.5 g/di
- total nucleated count greater than 25,000/ul
- polymorphonuclear cell count greater than 20,000/ul
A group of yearling steers were recently fed moldy sweet potatoes two days ago. Yesterday, they began to exhibit tachypnea, dyspnea, grunting, frothing at the mouth, deep cough, and respiratory distress. Today there are several dead. The lungs are wet, firm, and fail to collapse. Lobules are dark red and firm, with hemorrhages, edema, emphysema and bullae throughout the interstitial pneumonia. What is the cause of this disorder?
- 4-ipomeanol
- Bovine virus diarrhea
- 3-methylindole
- Mannheimia hemolytica
- Bovine respiratory syncytial virus
Answer: 4-ipomeanol
Explanation
A metabolite of 4-ipomeanol is a pneumotoxic compound that is produced by the fungus Fusarium solani acting on the sweet potato compound called 4-hydroxymyoporone. This metabolite is toxic to pulmonary tissues. Lesions are similar to those found with acute bovine pulmonary edema and emphysema (ABPE) caused by conversion of ingested L-tryptophan in lush pastures to pneumotoxic 3-methylindole.
The disorder in the steers is caused by 4-ipomeanol, a pneumotoxic compound produced by Fusarium solani acting on sweet potato 4-hydroxymyoporone. This toxin affects pulmonary tissues, causing lesions like those in acute bovine pulmonary edema and emphysema (ABPE) from L-tryptophan conversion to 3-methylindole in lush pastures. Symptoms include respiratory distress and lung pathology.
CGPT: 4-Ipomeanol Toxicosis (Moldy Sweet Potato) and Perilla Ketone Toxicosis (Purple Mint Toxicosis) in Cattle
Definitions and Causative Agents:
• 4-Ipomeanol Toxicosis: Caused by ingestion of moldy sweet potatoes infested with Fusarium solani, producing the pneumotoxin 4-ipomeanol. • Perilla Ketone Toxicosis: Caused by ingestion of leaves and seeds of Perilla frutescens (purple mint), containing a pneumotoxin.
Clinical Changes and Symptoms:
• Similar to acute bovine pulmonary emphysema and edema (ABPEE). • Symptoms: Severe dyspnea, frothy nasal discharge, coughing, tachypnea, and death in severe cases.
Diagnosis:
• Tests: History of ingestion, clinical signs, necropsy findings. • Findings: Pulmonary edema, emphysema.
Treatment:
• Medications: • Corticosteroids: Dexamethasone to reduce inflammation. • Diuretics: Furosemide to manage pulmonary edema. • Supportive Care: Oxygen therapy, maintaining hydration.
Prevention:
• Avoid feeding moldy sweet potatoes or exposure to purple mint.
https://www.merckvetmanual.com/respiratory-system/non-infectious-respiratory-system-diseases-in-cattle/4-ipomeanol-toxicosis-moldy-sweet-potato-and-perilla-ketone-toxicosis-purple-mint-toxicosis-in-cattle?redirectid=4694?ruleredirectid=30
A clinician calls you about a heifer he examined and mentions that he heard a murmur over what he thought was the aortic region. Over which intercostal space would an aortic valve murmur be heard best?
- Left 3rd intercostal space
- Right 3rd intercostal space
- Left 4th intercostal space
- Right 4th intercostal space
- Left 5th intercostal space
Answer: Left 4th intercostal space
Explanation
The correct answer is the left 4th intercostal space. We at VetPrep always think of our left-handed ex-girlfriend PAM. That stands for Pulmonic, Aortic and Mitral and then you just work your way from the 3rd intercostal space (pulmonic) to the 5th intercostal space (mitral). So the point of maximal intensity for an aortic murmur will be on the 4th intercostal space. Keep in mind that this is all on the left side. On the right side the only valve you can appreciate is the tricuspid valve which is audible best between the 3rd and 4th intercostal space.
The aortic valve murmur is best heard at the left 4th intercostal space. Remember “PAM” (Pulmonic, Aortic, Mitral), moving from the 3rd (pulmonic) to the 5th (mitral) intercostal space on the left side. The tricuspid valve is heard on the right side between the 3rd and 4th intercostal spaces.
A cow presents to you for decreased milk production. On physical exam, you determine the cow has a much stronger pulse on expiration than she does on inspiration. What is this pulse associated with?
- Pericardial effusion
- Atrial premature contractions
- Patent ductus arteriosus
- Atrial fibrillation
Answer: Pericardial effusion
Explanation
The correct answer is pericardial effusion. Pulsus paradoxus is an exaggeration of normal variations in the pulse quality during the respiratory cycle; the pulse becomes weaker on inhalation and stronger on exhalation. It is characteristic of constrictive pericarditis or pericardial effusion. Atrial premature contractions are more likely to result in pulse deficits.
Atrial fibrillation is likely to result in pulsus alternans, in which you see two quick normal pulses in a row followed by no pulse.
A patent ductus arteriosus usually is found only in very young animals and results in waterhammer pulses which is a large bounding pulse with a sharp peak and very rapid decline.
Pericardial effusion is associated with a stronger pulse on expiration than on inspiration, known as pulsus paradoxus. This exaggerated variation in pulse quality during the respiratory cycle is characteristic of pericardial effusion or constrictive pericarditis. In contrast, atrial premature contractions cause pulse deficits, and atrial fibrillation leads to pulsus alternans.
A very valuable dairy cow has died after a long illness with fever that the owner had treated with potent antimicrobial drugs for a week, then had given up. He asks you to perform a post-mortem to tell him the cause of death so he can collect insurance money. You find edematous lungs, edema in the ventral thoracic subcutaneous tissues, and this heart lesion. **What is the diagnosis?*
Valvular endocarditis
Pulmonary stenosis
White muscle disease
Tetralogy of Fallot
Ventricular septal defect
Answer: Valvular endocarditis
Explanation
Bacteria can lodge on heart valves and collect platelets and do damage to valves, causing murmurs and dysfunction and in some cases heart failure. The bacteria usually enter via a septic site such as a hoof abscess.
Valuable cows should be treated with penicillin or ceftiofur for several days if they develop hoof abscesses or similar problem.
The diagnosis is valvular endocarditis. Bacteria from a septic site, such as a hoof abscess, can lodge on heart valves, causing damage, murmurs, and potential heart failure. Valvular endocarditis is associated with edematous lungs and subcutaneous edema. Treatment for valuable cows with hoof abscesses includes penicillin or ceftiofur for several days.
What cardiac abnormality is commonly associated with hypocalcemia and milk fever in the cow?
Tachycardia
Atrial fibrillation
Ventricular premature contractions
Sinoatrial node block
Answer: Tachycardia
Explanation
The correct answer is tachycardia. Calcium administration may cause all the other abnormalities if you give too much too fast. You may also see a sinus node arrest. Calcium administration will cause the heart to beat more slowly and more strongly.
The cardiac abnormality commonly associated with hypocalcemia and milk fever in cows is tachycardia. Rapid calcium administration can cause other abnormalities, such as ventricular premature contractions, sinoatrial node block, or sinus node arrest, leading to a slower and stronger heartbeat.
** Parturient Paresis in Cows - Comprehensive Information**
Definitions and Causative Agents:
• Parturient Paresis (Milk Fever): Acute hypocalcemia causing flaccid paralysis around parturition.
• Causative Agents: Low blood calcium due to high calcium demand at lactation onset.
Clinical Findings:
• Stage 1: Hyperexcitability, ataxia, tremors.
• Stage 2: Sternal recumbency, cold extremities, tachycardia, dry muzzle.
• Stage 3: Lateral recumbency, coma, severe muscle flaccidity, potential death.
Diagnosis:
• Clinical Signs: Recumbency, muscle tremors, decreased heart sounds.
• Blood Tests: Hypocalcemia confirmation.
Treatment:
• Stage 1: Oral calcium supplements (40-55 g elemental calcium).
• Stage 2 & 3: IV calcium gluconate (500 mL of 23% solution), slow infusion.
Prevention:
• Dietary Management: Acidogenic diets prepartum (DCAD of -50 to -150 meq/kg).
• Monitoring: Urinary pH to maintain optimal acidification.
• Prophylactic Calcium: Oral calcium around calving.
A rancher has just found a big 2 month-old calf dead in the field and asks you to perform a post-mortem to determine the cause of death. He is worried about a contagious disease in his herd. You find the lungs are edematous and there is mild bronchopneumonia, but this lesion is found in the heart. Which diagnosis best fits?
Pulmonary stenosis
Tetralogy of Fallot
Ventricular septal defect
Patent ductus arteriosus
Bacterial endocarditis
Answer: Ventricular Septal Defect
Explanation
Congenital ventricular septal defect is one of the most commonly encountered congenital cardiac defects in cattle. It may be a relatively benign of cause death, depending on size. If the rancher sees several calves with this defect, he should discontinue using the bull responsible.
The diagnosis is ventricular septal defect, a common congenital cardiac defect in cattle. Its severity can vary, sometimes leading to death. If multiple calves are affected, the rancher should stop using the responsible bull to prevent further cases. Other diagnoses are less likely based on the findings.
A 7 year old Jersey cow presents to you with anorexia, bottle jaw, brisket edema, and a true jugular pulse. She has a heart rate of 90 bpm, rapid respiration, and is depressed. What is your primary differential?
Generalized lymphangitis
Right heart failure
Salt poisoning
Anaplasmosis
Answer: Right heart failure
Explanation
The correct answer is right heart failure. As a result of an inability to pump blood, it backs up and edema and a true jugular pulse occur.
The primary differential is right heart failure. The inability of the heart to pump blood effectively leads to backup, resulting in edema, bottle jaw, brisket edema, and a true jugular pulse. This is consistent with the cow’s clinical signs.
What is the most common supraventricular arrhythmia in cattle?
Atrial fibrillation
Ventricular fibrillation
Sinoatrial node arrest
Atrial standstill
Answer: Atrial fibrillation
Explanation
The correct answer is atrial fibrillation. This usually occurs as a result of digestive disturbances. It is associated with vagal tone, hypokalemia, hyperkalemia, and calcium therapy. You may be able to palpate a pulse deficit and/or pulsus alternans in these animals. On ECG, there will be no P waves because the sinoatrial node is not working. You will see random high frequency, low amplitude depolarizations called F waves. A QRS wave that occurs at irregular intervals will be present.
The most common supraventricular arrhythmia in cattle is atrial fibrillation, often resulting from digestive disturbances. It is linked to vagal tone, electrolyte imbalances, and calcium therapy. On ECG, there are no P waves, with irregular QRS waves and F waves due to sinoatrial node dysfunction.
You are in the process of performing an ECG on a Charolais cow with chronic pulmonary disease and notice that the P wave is tall and slender and measures 0.48mV (normal <0.4 mV), a condition known as P pulmonale. What conclusion as to the nature of the cardiac abnormality can you make from this finding?
Left atrial enlargement
Right atrial enlargement
Congestive heart failure
Left ventricular enlargement
Answer: Right atrial enlargement
Explanation
The correct answer is right atrial enlargement. This ECG finding is known as P pulmonale and is characterized by tall slender peaked P waves greater than 0.4mV. Many times these patients have a history of chronic pulmonary disease.
Left atrial enlargement on an ECG is known as P mitrale. In this case, an increase in duration of the P wave is seen. Usually they will last at least 0.05 seconds. The reason you see these electrical changes is because of the resulting vectors that are produced by having a certain portion of the heart enlarged.
The conclusion is right atrial enlargement, indicated by the P pulmonale finding on the ECG, characterized by tall, slender P waves over 0.4mV. This is commonly seen in patients with chronic pulmonary disease. Left atrial enlargement, or P mitrale, shows prolonged P wave duration instead of increased height.
A rancher who lives at 8000 ft. elevation in Colorado is planning to buy good bulls and wants you to test them for susceptibility to high mountain disease (pulmonary hypertension and cor pulmonale). See image for what high mountain disease looks like. You recommend doing pulmonary artery pressure (PAP) testing in the squeeze chute to measure their susceptibility to pulmonary hypertension. Which of the following PAP measurements, taken at 6000 ft. elevation, would be satisfactory for this ranch to purchase?
45 to 50 mmHg pressure
None, the testing must be done below 5000 ft. elevation to be reliable
None, there is no reliable way to predict susceptibility to high mountain disease
Less than 40 mmHg pressure
55 to 60 mmHg pressure
Answer: Less than 40mmHg pressure
Explanation
PAP testing done at elevations 6000 ft. or above on animals over 12 months of age is a reliable predictor of genetic susceptibility to high mountain disease (the BMPR gene is involved). The lowest pulmonary artery pressure readings are the least susceptible animals. Using local anesthesia, a catheter is inserted into the jugular vein and threaded into the right heart and pulmonary artery where the pressure is taken while the animal is restrained in a squeeze chute. The condition is caused by a genetic predisposition to developing pulmonary hypertension when oxygen tension is reduced. The pulmonary hypertension leads to pulmonary artery hypertrophy, cor pulmonale, and right heart failure. The hallmarks are lethargy, distended jugular vein, and ventral edema (see image), as well as diarrhea, pulmonary edema, and pleural effusion. Ingestion of toxic plants such as locoweed worsen the disease by causing additional pathology. Cold weather, pregnancy and other stresses can also predispose animals and cause borderline susceptible animals to develop the condition.
A satisfactory pulmonary artery pressure (PAP) measurement for bulls at 6000 ft. elevation to predict susceptibility to high mountain disease is less than 40 mmHg. PAP testing at elevations of 6000 ft. or above is reliable for detecting genetic susceptibility. Animals with lower pressures are less likely to develop pulmonary hypertension, cor pulmonale, and right heart failure.
** Bovine High-Mountain Disease (BHMD): NAVLE Study Guide**
Definitions and Etiology
• BHMD: Also known as “Brisket Disease,” it occurs in cattle at high altitudes due to hypoxia-induced pulmonary hypertension.
• Causative Factors: Genetic predisposition, high altitude, pulmonary vascular shunting, and locoweed poisoning (Oxytropis and Astragalus spp.).
Pathophysiology
• Mechanism: Hypoxia causes pulmonary arterial vasoconstriction and hypertrophy, leading to pulmonary hypertension, right ventricular hypertrophy, and eventual congestive heart failure.
• Vascular Remodeling: Chronic exposure results in loss of peripheral pulmonary arteries and increased pulmonary resistance.
Clinical Signs
• Symptoms: Brisket edema, pleural effusion, jugular distension, cyanosis, labored breathing, and sometimes exophthalmos. Animals may become recumbent and show signs of right heart failure.
• Advanced Signs: Ascites, profuse diarrhea, and decreased appetite due to intestinal venous hypertension.
Diagnosis
• Pulmonary Arterial Pressure (PAP): Elevated PAP (>50 mmHg) and visible signs of right ventricular failure. Radiographic and ultrasonographic findings support the diagnosis.
• Differential Diagnosis: Includes other causes of congestive heart failure, such as pericarditis, lymphosarcoma, and myocarditis.
Treatment
• Primary Treatment: Moving affected cattle to lower altitudes, supportive care, diuretics, and thoracocentesis. Affected cattle should not be returned to high altitudes.
• Prevention: Selective breeding for animals with lower PAP measurements, minimizing exposure to locoweed, and addressing concurrent diseases.
Key Points for Veterinary Professionals
• Genetic Selection: Breeding programs should focus on selecting cattle resistant to hypoxia.
• Environmental Management: Control exposure to high-altitude stressors and toxic plants like locoweed.
• Ongoing Research: Studies on genetic markers and improving diagnostic techniques for BHMD are critical for future prevention and management strategies.
In this type of arrhythmia, the P-R interval progressively gets larger until there is a dropped QRS complex (P wave without a QRS complex).
First degree heart block
Third degree heart block
Second degree Mobitz type I heart block
Second degree Mobitz type Il heart block
Answer: Second degree Mobitz type I heart block
Explanation
The correct answer is Second degree Mobitz type I heart block, also known as the Wenckebach beat. In a Mobitz type Il block, the P-R interval duration is unchanged and occasionally you will observe a P wave without a QRS complex. These blocks are thought to be caused by a refractory AV node which is not responding to a delayed atrial depolarization. In a 1st degree heart block, you will observe an increased P-R interval and no dropped QRS. In 3rd degree heart blocks, the P waves are unassociated from the QRS complex.
The arrhythmia described is a Second degree Mobitz type I heart block (Wenckebach beat), where the P-R interval progressively lengthens until a QRS complex is dropped. In contrast, Mobitz type II shows no P-R interval change but occasional dropped QRS complexes. First-degree heart block has an increased P-R interval without dropped QRS, and third-degree heart blocks show no association between P waves and QRS complexes.
A cow presents due to a decrease in milk production. On physical exam, you were unable to hear the heart clearly (it is muffled). You decide to perform an ECG and immediately recognize that this cow has electrical alternans. What is most likely to be occurring?
Right atrial enlargement
Pericardial effusion
Left ventricular enlargement
Right ventricular enlargement
Left atrial enlargement
Answer: Pericardial effusion
Explanation
The correct answer is pericardial effusion. Electrical alternans is a classic finding in cases where there is pericardial effusion. Electrical alternans is characterized by different amplitudes of multiple successive R waves in the QRS complex. This is thought to be a result of the heart shifting around within the fluid filled compartment of the pericardial sac.
The most likely condition is pericardial effusion. Electrical alternans, seen as varying R wave amplitudes in the QRS complex, is a classic sign of pericardial effusion. This occurs due to the heart shifting within the fluid-filled pericardial sac, leading to muffled heart sounds.
A 3-year old Jersey heifer is not doing well and is euthanized with a post-mortem performed in the field. Below is an image of her heart, with the right atrium and right ventricle opened. What is your diagnosis?
Tricuspid valve endocarditis
Ventricular septal defect
Cardiac neoplasia
No significant findings
Tricuspid valve dysplasia
Answer: Tricuspid valve endocarditis
Explanation
The correct answer is tricuspid valve endocarditis. Hemorrhagic and white masses are seen on all leaflets of the tricuspid valve which makes endocarditis the most likely diagnosis in a young heifer. Neoplasia is unlikely on the valve and at this age; tricuspid valve dysplasia would be seen as short, thick chordae but no masses; a VSD would be seen as a hole between the right and left ventricle which is not apparent here.
The diagnosis is tricuspid valve endocarditis. Hemorrhagic and white masses on all tricuspid valve leaflets are indicative of endocarditis, especially in a young heifer. Neoplasia is unlikely at this age and location. Tricuspid valve dysplasia would show thickened chordae without masses, and a ventricular septal defect would appear as a hole between ventricles, which is not present here.
Bovine Cardiac Diseases Overview:
• Cardiac diseases in bovine primarily affect the pericardium, myocardium, and endocardium. Congenital heart diseases, such as ventricular septal defects, are also noted but rare.
Pericardial Diseases:
• Common Diseases: Traumatic pericarditis, pericarditis secondary to pleural or lung infections, neoplastic effusions due to lymphoma or mesothelioma, and idiopathic aseptic pericarditis.
• Pathophysiology: Inflammation of the pericardium due to trauma or infection leads to the accumulation of serous or fibrinous products. The proximity of the reticulum to the pericardium in cattle increases the risk of traumatic pericarditis, particularly due to hardware disease.
• Symptoms: Tachycardia, muffled heart sounds, jugular vein distension, ventral edema, anorexia, decreased milk production, and pyrexia. In advanced cases, there may be diarrhea, congested mucous membranes, and increased capillary refill time.
• Diagnostics: Clinical signs, radiographic findings (enlarged cardiac silhouette), ultrasonography, echocardiography (gold standard), and electrocardiography (base-apex lead system).
• Treatment: Digoxin to improve venous return and reduce afterload, antibiotics like amoxicillin or aminoglycosides, pericardiocentesis for fluid drainage, and in severe cases, surgical pericardiotomy or pericardiectomy.
• Prognosis: Generally poor, with treatments aimed at short-term survival for calving or superovulation.
Myocardial Diseases:
• Common Diseases: Dilated cardiomyopathy (DCM) is the most common myocardial disease in cattle, often affecting Holstein-Friesian cattle due to possible genetic factors.
• Pathophysiology: DCM involves myocardial dysfunction due to various etiologies, including immune dysfunction, viral infections, and genetic predispositions. Other causes include toxic effects from ionophores or selenium deficiency.
• Symptoms: Subcutaneous edema, jugular vein distension, ascites, heart murmurs, diarrhea, and muffled heart sounds.
• Diagnostics: Clinical signs, echocardiography, and biochemical analysis (elevated liver enzymes, creatinine, and transferrin).
• Treatment: No specific treatment for DCM. Supportive care includes correcting electrolyte imbalances and treating underlying causes.
• Prognosis: Fatal in primary DCM; prognosis improves with early detection and resolution of secondary causes.
Endocardial Diseases:
• Common Diseases: Bacterial endocarditis, often secondary to chronic infections (e.g., mastitis, metritis, or abscesses).
• Pathophysiology: Persistent bacteremia leads to endocardial infection, with common bacteria being Arcanobacterium pyogenes and streptococci.
• Symptoms: Weight loss, decreased milk production, tachycardia, murmurs, jugular distension, fever, and edema.
• Diagnostics: Hematological findings (anemia, leukocytosis), echocardiography (vegetative lesions), and blood cultures.
• Treatment: Long-term antibiotic therapy (minimum of four weeks) to arrest valve destruction and eliminate sepsis.
• Prognosis: Dependent on early diagnosis; prognosis worsens with delayed treatment.
Congenital Heart Diseases:
• Common Conditions: Ventricular septal defects, atrial septal defects, and patent ductus arteriosus.
• Symptoms: Ill-thrift, poor growth, respiratory disease, and sudden death.
• Diagnostics: Echocardiography and radiography for assessing congenital defects.
• Treatment: No surgical or medicinal treatments available for congenital heart disease in cattle.
• Prognosis: Varies from guarded to poor.
Cardiac Neoplasia:
• Common Tumors: Lymphoma is the most common, along with others like hemangiosarcoma, fibrosarcoma, and mesothelioma.
• Symptoms: Similar to pericarditis or congestive heart failure, with additional signs of neoplasia like lymphadenopathy.
• Diagnostics: Peripheral lymph node aspirates, echocardiography, and pericardiocentesis.
• Treatment: Palliative treatments like thoracoscopic pericardiotomy or repeated pericardiocentesis; antibiotics and diuretics for symptom management.
• Prognosis: Generally poor, with short-term survival following palliative care.
Congestive Heart Failure (CHF):
• Pathophysiology: Result of progressive heart disease leading to fluid retention and edema.
• Symptoms: Syncope, exercise intolerance, weakness, effusion, and edema.
• Diagnostics: Clinical signs, echocardiography, and blood gas analysis.
• Treatment: Digoxin for initial therapy, potassium supplementation, and cautious use of furosemide to resolve edema.
• Prognosis: Short-term improvement possible with medicinal therapy; long-term outcomes are generally poor.
https://www.researchgate.net/profile/Ashwani-Kumar-54/publication/336121748_An_overview_on_the_diagnostic_and_therapeutic_aspects_of_cardiac_diseases_in_bovine/links/5d8f9b26299bf10cff17f7b4/An-overview-on-the-diagnostic-and-therapeutic-aspects-of-cardiac-diseases-in-bovine.pdf
This 3 1/2 month old calf presents for weakness and failure to thrive. On physical exam you find normal temperature but rapid heart and respiratory rates. A loud holosystolic murmur is heard on both sides of the thorax with maximal intensity in the region of the tricuspid valve. It is also clearly heard on the left side with maximal intensity near the pulmonic valve (far forward). What is the most likely diagnosis?
Endocarditis
Ventricular septal defect
Patent ductus arteriosus
Patent foramen ovale
Traumatic reticulopericarditis
Answer: Ventricular septal defect
Explanation
The correct answer is ventricular septal defect. In order to answer this question, you need to “play the odds” and know that VSDs are the most common congenital heart defect in cattle, and they usually present at about 2-3 months of age because they are failing to thrive and/or are developing pulmonary edema and secondary pneumonia. This defect results in oxygenated blood being pushed back into the right atrium and ventricle. In addition, you will see right ventricular dilation and hypertrophy. The increased flow through the right side creates a relative pulmonic stenosis, and thus the murmur is also heard on the left side in the area of the pulmonic valve. VSD is the most common congenital defect in cattle.
The most likely diagnosis is a ventricular septal defect (VSD). VSDs are the most common congenital heart defect in cattle, usually presenting at 2-3 months of age with failure to thrive. The defect causes oxygenated blood to flow back into the right atrium and ventricle, leading to right ventricular dilation, hypertrophy, and a murmur heard on both sides of the thorax.
Which of the following is not a feature of Tetralogy of Fallot?
Pulmonic valve stenosis
Aortic valve stenosis
Ventricular septal defect
Right ventricular hypertrophy
Dextropositioned aorta
Answer: Aortic Valve Stenosis
Explanation
The correct answer is aortic valve stenosis. Excellent job if you remembered this one! In case you don’t remember the four features of Tetralogy of Fallot, they are: Right ventricular hypertrophy, ventricular septal defect, dextropositioned aorta (over-riding aorta), and pulmonic valve stenosis. Clinical signs include a bilateral basilar murmur, right sided heart failure, cyanosis, and secondary bacterial endocarditis.
***PowerLecture: Cardiology Disease Specific Pearls of Wisdom
* Tetralogy of Fallot in Animals
Definition:
• Congenital heart defect with four components: pulmonic stenosis, ventricular septal defect, right ventricular hypertrophy, and overriding aorta.
Affected Species:
• Dogs (e.g., Keeshonds, English Bulldogs), cats.
Clinical Signs:
• Cyanosis, exercise intolerance, stunted growth, collapse, seizures. • Loud ejection heart murmur, precordial thrill.
Diagnosis:
• Echocardiography: Confirms structural defects. • Radiographs: Right heart enlargement. • ECG: Right ventricular enlargement.
Treatment:
• Beta-adrenergic blockers to manage outflow obstruction. • Periodic phlebotomy for polycythemia. • Surgical options: Palliative techniques, valvuloplasty.
Control:
• Manage based on severity, supportive care, and specific surgical interventions.
While performing a physical exam on a cow, you notice a rapid irregular heart rate with no atrial sounds or compensatory pauses. There is no regular rhythm to the irregularity. What is this?
Sinus arrhythmia
Ventricular tachycardia
Bradyarrhythmia
Atrial fibrillation
Answer: Atrial fibrillation
Explanation
This is descriptive for atrial fibrillation. If you ran an ECG, you would find no P waves and variable intervals between QRS complexes. Atrial fibrillation is the most common arrhythmia in cattle, often due to Gl or electrolyte abnormalities.
The condition described is atrial fibrillation. It presents as a rapid, irregular heart rate without atrial sounds or compensatory pauses, and an irregular rhythm. On ECG, you’d find no P waves and variable intervals between QRS complexes. Atrial fibrillation is common in cattle, often linked to GI or electrolyte abnormalities.
You examine a valuable beef bull that was recently purchased in Texas and taken to the mountains of Colorado. The pasture is a mountain meadow at 10,000 feet elevation. The bull has developed edema of the brisket and ventral thorax, submandibular edema, dyspnea and tachypnea. Rectal temperature is normal. The HR is 90, and heart sounds are clearly audible without murmurs. What is your diagnosis?
Ventricular septal defect
Valvular endocarditis
Cardiomyopathy
High mountain disease
Traumatic pericarditis
Answer: High mountain disease
Explanation
The key to this question is the altitude mentioned in the question and accompanying clinical signs. Also called brisket disease and high altitude disease, this condition can be fatal and is brought on by elevations above 6000 feet. Hypoxic vasoconstriction (worse in some lines of cattle) causes pulmonary hypertension, which leads to cor pulmonale, which is secondary cardiac disease including right heart enlargement and failure.
The diagnosis is high mountain disease, also known as brisket disease or high altitude disease. This condition occurs at elevations above 6000 feet, causing hypoxic vasoconstriction, leading to pulmonary hypertension, cor pulmonale, right heart enlargement, and failure. The clinical signs include brisket edema, submandibular edema, dyspnea, and tachypnea, with normal rectal temperature and clear heart sounds.
Bovine High-Mountain Disease (BHMD): NAVLE Study Guide
Definitions and Etiology
• BHMD: Also known as “Brisket Disease,” it occurs in cattle at high altitudes due to hypoxia-induced pulmonary hypertension.
• Causative Factors: Genetic predisposition, high altitude, pulmonary vascular shunting, and locoweed poisoning (Oxytropis and Astragalus spp.).
Pathophysiology
• Mechanism: Hypoxia causes pulmonary arterial vasoconstriction and hypertrophy, leading to pulmonary hypertension, right ventricular hypertrophy, and eventual congestive heart failure.
• Vascular Remodeling: Chronic exposure results in loss of peripheral pulmonary arteries and increased pulmonary resistance.
Clinical Signs
• Symptoms: Brisket edema, pleural effusion, jugular distension, cyanosis, labored breathing, and sometimes exophthalmos. Animals may become recumbent and show signs of right heart failure.
• Advanced Signs: Ascites, profuse diarrhea, and decreased appetite due to intestinal venous hypertension.
Diagnosis
• Pulmonary Arterial Pressure (PAP): Elevated PAP (>50 mmHg) and visible signs of right ventricular failure. Radiographic and ultrasonographic findings support the diagnosis.
• Differential Diagnosis: Includes other causes of congestive heart failure, such as pericarditis, lymphosarcoma, and myocarditis.
Treatment
• Primary Treatment: Moving affected cattle to lower altitudes, supportive care, diuretics, and thoracocentesis. Affected cattle should not be returned to high altitudes. • Prevention: Selective breeding for animals with lower PAP measurements, minimizing exposure to locoweed, and addressing concurrent diseases.
Key Points for Veterinary Professionals
• Genetic Selection: Breeding programs should focus on selecting cattle resistant to hypoxia.
• Environmental Management: Control exposure to high-altitude stressors and toxic plants like locoweed.
• Ongoing Research: Studies on genetic markers and improving diagnostic techniques for BHMD are critical for future prevention and management strategies.
When performing a necropsy on a cow, you find multiple abnormalities including abomasal ulcers, interstitial pneumonia, pericardial effusion, and mastitis. You also see that the liver has a brown- (tan) and red-mottled lobular pattern described as a nutmeg liver. Which of these conditions in the cow could lead to the necropsy findings in the liver?
Pericardial effusion
Abomasal ulcers
Interstitial pneumonia
Mastitis
Answer: Pericardial effusion
Explanation
The appearance of a nutmeg liver occurs because there are red central veins and sinusoids between tan areas of swollen hepatocytes. This occurs with right sided heart failure from passive congestion of the sinusoids of hepatocellular hypoxia. Pericardial effusion causes right sided heart failure and is the cause of the liver’s appearance.
The condition that could lead to the nutmeg liver appearance in the cow is pericardial effusion. This occurs due to right-sided heart failure, resulting in passive congestion of the liver’s sinusoids and hepatocellular hypoxia, causing the characteristic red and tan mottled pattern seen on necropsy.
Bovine growth hormone is also called bovine somatotropin (BST). For which approved purpose is BST sometimes given to cattle?
-Produce larger cows capable of avoiding dystocia
-Increase the rate of growth in feedlot cattle
-Prevent milk fever in dairy cattle
-Produce twinning in dairy cows
-Promote milk production
Answer: Promote milk production
Explanation
BST or rBST is given by injection to lactating dairy cows every two weeks to increase the amount of milk produced and to prolong lactation.
Bovine growth hormone, or bovine somatotropin (BST), is given to lactating dairy cows to promote milk production. It is typically administered by injection every two weeks to increase milk yield and extend the lactation period.
Bovine growth hormone is also called bovine somatotropin (BST). For which approved purpose is BST sometimes given to cattle?
-Produce larger cows capable of avoiding dystocia
-Increase the rate of growth in feedlot cattle
-Prevent milk fever in dairy cattle
-Produce twinning in dairy cows
-Promote milk production
Answer: Promote milk production
Explanation
BST or rBST is given by injection to lactating dairy cows every two weeks to increase the amount of milk produced and to prolong lactation.
Bovine growth hormone, or bovine somatotropin (BST), is given to lactating dairy cows to promote milk production. It is typically administered by injection every two weeks to increase milk yield and extend the lactation period.
You examine a 3-year old beef cow which has been acting depressed for the last 24 hours, and has failed to remain with the herd. The cow’s temperature is 104F, (40 C), heart rate is 100 bpm and is pounding loudly, and the respiratory rate is elevated at 42 breaths per minute. The mucous membranes are pale. You take a blood sample back to your nearby clinic and observe the blood smear (see image). The PCV is 20% (24-46%). Of the following, what is the single best, most cost-effective treatment for this cow?
- Long acting tetracycline injection
- Whole blood transfusion
- Procaine penicillin injection
- Vaccinate against parainfluenza-3
- Imidocarb dipropionate injection
Answer: Long acting tetracycline injection
Explanation
The blood smear shows multiple round Anaplasma marginale along the outer membrane of red blood cells.
Anaplasma marginale is an obligate intracellular bacterium. It is the most prevalent tick-borne pathogen of cattle worldwide and is endemic in tropical and sub-tropical regions. Canada is Anaplasma-free.
Infection causes large scale destruction of red blood cells and fever, weight loss, respiratory distress, abortion, and often death.
Although some cattle recover, they can become lifetime carriers as reservoirs. Anaplasma ovis can occur in sheep and goats.
Anaplasma can often be treated successfully with a single injection of long acting tetracycline (20 mg/kg).
When the PCV is below 12%, a blood transfusion may also be needed. In addition, the animal should be given ready access to feed and water.
Even with treatment, animals may remain carriers after all clinical signs resolve.
The best and most cost-effective treatment for this cow with Anaplasma marginale infection is a single injection of long-acting tetracycline (20 mg/kg). Anaplasma marginale is a tick-borne intracellular bacterium that causes red blood cell destruction, leading to fever, weight loss, respiratory distress, and anemia. A blood transfusion may be necessary if the PCV drops below 12%.
Anaplasmosis in Ruminants - Comprehensive Veterinary Information
Definitions and Terminology:
• Anaplasmosis: A tick-borne disease of ruminants caused by intracellular bacteria infecting red blood cells, leading to severe anemia and fever.
Causative Agents:
• Pathogens: Anaplasma marginale, A. centrale, A. ovis, A. phagocytophilum.
Physiopathology:
• Transmission: Ticks (Dermacentor, Rhipicephalus), mechanical via biting dipterans, contaminated needles. • Pathogenesis: Bacteria infect erythrocytes, causing their destruction by the immune system, leading to anemia and jaundice.
Clinical Findings:
• Symptoms: Progressive anemia, fever, weight loss, decreased milk production, icterus. Severe cases may lead to death.
Diagnosis:
• Tests: Blood smears (Giemsa-stain), serologic tests (ELISA), PCR. • Microscopic Findings: Anaplasma organisms in erythrocytes.
Treatment:
• Antibiotics: Tetracyclines (e.g., oxytetracycline 20 mg/kg IM), imidocarb (1.5 mg/kg SC). • Supportive Care: Blood transfusions for severely affected animals.
Control and Prevention:
• Vaccination: Use of live vaccines (e.g., A. centrale) in endemic areas. • Tick Control: Acaricides and environmental management.
Nine out of 100 adult cattle are found weak, depressed, and staring into space. On physical exam, they are found to be pale, icteric, and febrile. None of them have hemoglobinuria. The nine cattle all arrived at the ranch approximately one month ago. What is your most likely diagnosis?
- Leptospirosis
- Anthrax
- Bacillary hemoglobinuria
- Anaplasmosis
Answer: Anaplasmosis
Explanation
The correct answer is Anaplasmosis. The causative agent is Anaplasma marginale. The clinical signs are fairly straight forward, and you need to pick up on a couple key features. The fact that new adults are sick is one feature because cattle are resistant to clinical Anaplasmosis as calves. Also, it should be remembered that hemoglobinuria with Anaplasmosis is never seen because it is all extravascular hemolysis. Since there is no hemoglobinuria, leptospirosis, bacillary hemoglobinuria, and anthrax can be ruled out. Additionally, icterus with anthrax is not seen.
The most likely diagnosis is Anaplasmosis, caused by Anaplasma marginale. Key signs include weakness, depression, pallor, icterus, and fever, especially in newly arrived adult cattle. Unlike other conditions, hemoglobinuria is absent due to extravascular hemolysis. This rules out leptospirosis, bacillary hemoglobinuria, and anthrax, where hemoglobinuria and different signs occur.
You examine a 7-year-old dairy cow with the presenting complaint of poor milk production and weight loss. You find a normal TPR, but the cow is in poor body condition compared to others in the string, and has multiple enlarged lymph nodes at widely scattered locations (see image). You suspect bovine leukosis virus (BLV) has caused clinical lymphoma. Which of the following tests would be the most definitive in making the diagnosis of lymphoma?
- WBC count
- Aspirate lymph node and make slide
- Lymphocyte count
- AGID for BLV antibodies
- ELISA for BLV antibodies
Answer: ELISA for BLV antibodies
Explanation
The best answer to this question is ELISA for BLV antibodies. A biopsy is definitive if you can demonstrate antigen with immunohistochemistry, but many diagnostic labs do not have this capability, so this answer option was not included for this question. The ELISA for BLV only reveals that the cow has antibodies to BLV virus, but not that she has clinical lymphoma. However, multiple enlarged lymph nodes and a positive BLV antibody test are strongly suggestive of lymphoma.
A negative ELISA test would rule out BLV and associated lymphoma.
Aspiration of lymph nodes can lead to false positives, as many inflamed reactive nodes in cattle can have cells that look neoplastic.
The AGID for BLV antibodies is less sensitive than ELISA. The WBC and lymphocyte count lacks sensitivity and specificity.
The most definitive test for diagnosing lymphoma in a cow with suspected bovine leukosis virus (BLV) is the ELISA for BLV antibodies. While it indicates BLV exposure, it strongly suggests lymphoma when paired with multiple enlarged lymph nodes. A negative ELISA rules out BLV and associated lymphoma. Other methods, such as lymph node aspiration, can lead to false positives, and AGID is less sensitive than ELISA.
Bovine Leukosis: Comprehensive Information
Definition
• Bovine Leukosis (Bovine Lymphosarcoma): A cancerous disease caused by Bovine Leukemia Virus (BLV), an oncogenic retrovirus.
Etiology and Transmission
• Causative Agent: Bovine Leukemia Virus (BLV), a C-type oncogenic retrovirus. • Transmission: Primarily horizontal through blood transfer (e.g., contaminated needles, dehorning tools), and rarely vertical (transplacental or via colostrum).
Epidemiology
• Prevalence: High in US dairy herds (~46.5%) and lower in beef herds (~10.3%).
Pathogenesis
• Infection Outcomes: • Asymptomatic: Most animals show no signs. • Persistent Lymphocytosis: ~29% develop this benign condition. • Lymphosarcoma: <5% develop cancerous tumors.
Clinical Findings
• Juvenile Lymphosarcoma: Weight loss, fever, dyspnea, bloat, and posterior paresis. • Thymic Lymphosarcoma: Cervical swelling, dyspnea, bloat, jugular distention, tachycardia. • Cutaneous Lymphosarcoma: Cutaneous plaques, enlarged lymph nodes.
Diagnosis
• Serology: ELISA and PCR for BLV detection. • Cytology/Histology: Biopsy for diagnosing lymphosarcoma.
Treatment and Control
• No Treatment: No effective treatment; symptomatic care with corticosteroids. • Control Measures: Testing and culling infected animals, disinfection of equipment, using single-use needles.
Prevention
• Blood Precautions: Avoiding exposure to blood from infected animals. • Colostrum Management: Using colostrum from seronegative cows. • Farm Practices: Cleaning equipment and facilities, controlling flies.
Zoonotic Risk
• Human Risk: Potential, but not well-established, zoonotic risk through ingestion of unpasteurized dairy products.
You are called by a rancher and asked to examine a 3-year old beef cow he purchased 4 weeks ago and turned out in the hills of California. The complaint is that she appears weak and disoriented, and even a little belligerent. On exam, you find T=105F or 40.6 C, HR=110, and RR=45. The heart is pounding very loudly and you note a number of ticks on her. Mucous membranes are pale (see image of her vulva), but urine and feces appear normal. Other parameters are not notably abnormal. Which of the following diseases best fits this cow’s clinical signs?
- Piroplasmosis (Babesiosis)
- Purpura hemorrhagica
- Anaplasmosis
- Porphyria
- Bacillary hemoglobinuria (Clostridium novyi type D)
Answer: Anaplasmosis
Explanation
This tick-borne disease has an incubation period of 2 to 4 weeks, and causes these exact signs. Tetracycline is the best treatment.
With piroplasmosis or Clostridium novyi type D infection (bacillary hemoglobinuria), one would expect intravascular hemolysis and dark urine.
You are in the process of giving a cow a blood transfusion and begin to notice tachycardia, dyspnea, ptyalism, and rough lung sounds. Which of the following is NOT a treatment option?
- Epinephrine
- Diazepam
- Dexamethasone phosphate
- Antihistamine
- Oxygen
Answer: Diazepam
Explanation
The correct answer is diazepam. The clinical signs that are described are those of an anaphylactic reaction to the transfusion. Diazepam will not help you in this situation. Epinephrine, antihistamines, dexamethasone, IV fluids and oxygen are all possible treatment options.
You are consulting on a shipment of imported cattle that have arrived in Canada from South America. Ticks have been found on several cattle while they are in quarantine and yesterday one became ill with fever and hemolysis. Hemoglobinuria was observed. A blood smear from this animal is sent to you (see image). Given their origin, the ticks and hemoglobinuria observed, and what you see in the smear, which of the following is the most likely diagnosis?
- Transport stress induced hemolytic syndrome
- Babesiosis
- Copper toxicity
- Bacillary hemoglobinuria
- Anaplasmosis
Answer: Babesiosis
Explanation
Babesia bigemina and Babesia bovis are red cell parasites of cattle found in the Americas and spread mainly by Boophilus ticks. Other species of Babesia can infect man and other animals and are found on most continents.
The disease they cause is characterized by hemolytic anemia, hemoglobinuria (which differentiates it from anaplasmosis), icterus, and death. Bovine babesiosis is also called piroplasmosis, red water, Texas fever, or tick fever. Eradication of Boophilus ticks has been an effective means of control in the United States.
The most likely diagnosis is babesiosis, caused by Babesia bigemina or Babesia bovis, red cell parasites spread by Boophilus ticks in the Americas. Babesiosis leads to hemolytic anemia, hemoglobinuria (distinguishing it from anaplasmosis), icterus, and death. Known as piroplasmosis, red water, Texas fever, or tick fever, eradication of Boophilus ticks controls the disease.
Babesiosis in Animals - Comprehensive Veterinary Information
Definitions and Terminology:
• Babesiosis: A disease caused by Babesia spp., transmitted by ixodid ticks, affecting various mammals, including cattle, horses, sheep, goats, pigs, dogs, and cats.
Causative Agents:
• Pathogens: Various Babesia species, e.g., B. bovis, B. bigemina in cattle; B. canis, B. gibsoni in dogs.
Physiopathology:
• Transmission: Tick bites, transovarial transmission in ticks. • Pathogenesis: Intraerythrocytic protozoan parasites cause erythrocyte destruction, leading to anemia, hemolysis, and potential organ damage.
Clinical Findings:
• Symptoms: Fever, anemia, jaundice, hemoglobinuria, lethargy, weight loss, and in severe cases, CNS involvement. • Postmortem Lesions: Enlarged spleen, swollen liver, congested kidneys, and general anemia.
Diagnosis:
• Tests: Blood smear microscopy, PCR assays, serologic tests. • Microscopic Examination: Identification of parasites in erythrocytes.
Treatment:
• Babesiacides: Imidocarb dipropionate (1.2 mg/kg SC), diminazene aceturate (3.5 mg/kg IM). • Supportive Care: Anti-inflammatories, corticosteroids, fluid therapy, blood transfusions.
Control and Prevention:
• Tick Control: Acaricides, resistant breeds, management practices. • Vaccination: Live attenuated vaccines in some countries.
A beef cow presents for decreased milk production. On physical exam, the cow has a fever of 104.5F. Her urine is yellow, and the dipstick tests are normal. You make a blood smear and see an organism at the margin of the red blood cells. What is your treatment of choice for this animal?
- Procaine Penicillin
- Oxytetracycline
- Chloramphenicol
- Corticosteroids
Answer: Oxytetracycline
Explanation
The correct answer is oxytetracycline. The cow has Anaplasmosis, a rickettsial organism that is transmitted by ticks. Infected calves have a low mortality rate, but adult cattle have a 20-50% mortality rate with this disease.
You are working with a farmer who is having trouble with calves between the age of 2 weeks and 6 months. They are alert, but weak, dyspneic and die suddenly. On necropsy they have pale cardiac and skeletal muscles. What is the farmer’s problem?
- Lightning strike
- Sorghum toxicity
- Copper deficiency
- Selenium deficiency
Answer: Selenium deficiency
The correct answer is selenium deficiency. The pale muscle and clinical signs are classic for vitamin E and selenium deficiency. This is important to remember! Other things that should be on your differential list for this case include cardiotoxic plants.
Nutritional Myopathies in Ruminants and Pigs: Comprehensive Information
Nutritional Myodegeneration (NMD)
Definition: Acute, degenerative disease of cardiac and skeletal muscle due to selenium or vitamin E deficiency in young, rapidly growing animals.
Causative Agents:
• Selenium Deficiency: More critical than vitamin E deficiency. • Vitamin E Deficiency: Common in animals fed poor-quality hay or straw.
Clinical Signs:
• Cardiac Muscle: Respiratory distress, arrhythmias, sudden death. • Skeletal Muscle: Muscle weakness, stiffness, difficulty rising, respiratory distress, dysphagia.
Diagnosis:
• Laboratory Tests: Increased CK, AST, LDH levels. • Definitive Diagnosis: Low selenium in blood/liver, low vitamin E in plasma.
Treatment:
• Injectable Selenium: 0.055–0.067 mg/kg IM or SC. • Vitamin E Supplements: Oral supplementation, injectable products with 300-500 IU vitamin E/mL.
Prevention:
• Dietary Management: Selenium supplementation in feed, periodic injections, high-quality forage.
Hypokalemic Myopathy
Definition: Severe muscle weakness due to low serum potassium (< 2.0 mmol/L) in dairy cattle, often associated with isoflupredone acetate administration.
Clinical Signs: Weakness, recumbency, abnormal head/neck position, rumen hypomotility, anorexia, tachycardia.
Diagnosis: Clinical signs, serum potassium < 2.0 mmol/L, increased CK and AST.
Treatment: Potassium chloride supplementation, addressing primary cause of ketosis and anorexia.
Nutritional Myopathy of Pigs
Specific Conditions: Mulberry heart disease, hepatosis dietetica.
Causative Agents: Selenium or vitamin E deficiency, iron dextran administration.
Clinical Findings:
• Mulberry Heart Disease: Sudden death, pericardial effusion, myocardial necrosis. • Hepatosis Dietetica: Subcutaneous edema, serous cavity transudate, liver necrosis.
Diagnosis: History, clinical signs, necropsy, histology, serum/tissue selenium and vitamin E levels.
Treatment: Selenium and vitamin E supplementation, injections to affected pigs and sows in late gestation.
A 3-year-old beef cow presents with 4 days’ history of poor appetite and rapid weight loss. The cow had calved 10 days previously and had prolapsed her uterus immediately after delivery of a large dead calf that had been “hip-locked”. The cow had received no antibiotics because the uterus was replaced easily and the placenta was already detached from the caruncles. The cow is now weak and depressed. The rectal temperature is 100.8F (38.2 C). The ocular and oral mucous membranes appear slightly congested. The heart rate is 96 beats per minute. The respiratory rate is 30 breaths per minute with a slight abdominal component. The ruminal contractions are reduced and the cow has passed only scant feces. Rectal examination reveals that the uterus is still extending well beyond the pelvic inlet. Vaginal examination reveals approximately 200 mL of foul-smelling brown fluid. Despite treatment with intravenous oxytetracycline and flunixin meglumine for suspected metritis the cow died suddenly 2 days later. Postmortem examination reveals septic metritis and the liver lesions shown here. What condition is affecting the liver?
- Fasciola hepatica
- Mycobacterium paratuberculosis
- Clostridium chauvei
- Fusobacterium necrophorum
Answer: Fusobacterium necrophorum
Explanation
The image shows widespread severe liver abscesses caused by Fusobacterium necrophorum. Fusobacterium necrophorum is a gram-negative, obligate anaerobic bacterium that is a component of normal rumen microflora. In this case, the metritis caused bacteremic spread of the organism which can go to the liver and release local toxins leading to damage and potential abscess formation. Typical Fusobacterium lesions are yellow and spherical with irregular outlines. A diagnosis could be confirmed in this case by culture of the uterine contents and liver. Affected livers are condemned at slaughter. Adhesions to surrounding organs or the diaphragm may require carcass trimming. Liver abscess can also lead to disease associated with thrombosis of the vena cava.
The utility of prophylactic antibiotic therapy in large animal practice is unclear and this practice is often questioned with respect to cost, food safety (milk and meat withdrawal periods), and selection for antibiotic resistance in certain bacterial species. However, in this particular case, prophylactic antibiotics after replacement of the uterine prolapse may have prevented/cleared the uterine infection and/or prevented the bacteremia seeding the liver with fatal consequences.
Fasciola hepatica is the liver fluke of cattle. While Fasciola can cause liver lesions, the lesions typically appear more as tracks and/or hemorrhage. Animals with fasciolosis typically present with abdominal pain or jaundice acutely. Chronically, animals become anemic or anorectic.
Clostridium chauvei is the cause of blackleg in cattle and sheep and causes lameness and fever.
Mycobacterium paratuberculosis is the cause of Johne’s Disease which results in chronic wasting.
The liver condition in this case is caused by Fusobacterium necrophorum, a gram-negative anaerobic bacterium that can spread through bacteremia from metritis, resulting in liver abscesses. These abscesses are typically yellow, spherical, and irregular. Diagnosis is confirmed by culturing uterine contents and liver samples. Prophylactic antibiotics might have prevented this bacteremia after the uterine prolapse. Other liver-affecting conditions like Fasciola hepatica or Clostridium chauvei cause different lesions and clinical signs.
Key Information on Vena Caval Thrombosis and Metastatic Pneumonia in Cattle
Etiology
• Primary Cause: Ruminal acidosis leading to rumenitis and liver abscessation, with potential for thrombus formation in the caudal vena cava. • Bacteria Involved: Fusobacterium necrophorum, Trueperella pyogenes, staphylococci, streptococci, Escherichia coli.
Clinical Findings
• Acute Signs: Respiratory distress. • Chronic Signs: Weight loss, chronic coughing, tachypnea, tachycardia, hemic murmurs, coughing, pale mucous membranes, increased lung sounds, hemoptysis, and epistaxis.
Diagnosis and Lesions
• Diagnosis: Clinical signs, history, and postmortem examination. • Post-Mortem Lesions: Thrombus in the vena cava, hepatic abscesses, suppurative pneumonia with multifocal abscesses and aneurysms.
Treatment and Control
• Treatment: Antimicrobial therapy is usually ineffective; focus on supportive care. • Control: Nutritional management, gradual adaptation to high-grain diets.
A 2-year old Holstein heifer presents for depression and decreased milk production over the previous week. On physical exam, it is noted her posterior shape is “papple” and she is slightly dehydrated. T=100.2 (37.9 C), P=62, R=28. She does not have episcleral injection. Rumen contractions are not present. Xiphoid pain response is negative and you are able to hear a monotone ping in the rumen on the left side from the 11th rib to the hip. On ballottement and rectal exam a large fluid-filled rumen is palpable. Which of the following is the most likely diagnosis?
- Grain overload (rumen acidosis)
- Failure of omasal transport
- Abomasal torsion or volvulus
- Left displaced abomasum (LDA)
Anwer: Failure of omasal transport
Explanation
The correct answer is failure of omasal transport, a form of vagal indigestion, which leads to an accumulation of fluid and some dorsal gas in the rumen, lack of motility, and inappetance. TRP is a common cause of vagal indigestion; the negative grunt test for xiphoid pain is the result of chronicity and formed adhesions that are no longer acutely painful. It is difficult to clinically distinguish between omasal transport failure and pyloric outflow failure, except that the latter usually has more profound acid-base and electrolyte disturbances, and the cow will appear sicker as a result.
Abomasal torsion can be immediately ruled out because there is no abomasal ping on the right. In addition, if it were a right displaced abomasum, the cow would be showing more signs of distress and systemic disease such as episcleral injection and an elevated heart rate. Left displaced abomasum can be ruled out because the ping is monotone (LDA ping is variable in pitch) and the ping extends all the way back to the hip. Further, the large fluid filled rumen is rectally palpable, whereas a cow with LDA would have an empty rumen. Grain overload (rumen acidosis) would have a large fluid filled rumen, but the cow would be very sick with scleral injection and rapid heart rate.
***PowerLecture: Vagal Indigestion
The most likely diagnosis for this Holstein heifer is failure of omasal transport, a form of vagal indigestion. This condition leads to fluid accumulation, dorsal gas in the rumen, lack of motility, and inappetence. Omasal transport failure and pyloric outflow failure are hard to distinguish clinically, but the latter usually causes more severe electrolyte imbalances and systemic illness. Abomasal torsion, left displaced abomasum, and grain overload are ruled out due to the monotone ping, fluid-filled rumen, and absence of severe systemic signs.
You are called to examine and treat a cow which has eaten green chop alfalfa and has bloat. You first pass a stomach tube but little or no gas escapes, and the cow is in respiratory distress due to the tremendous abdominal pressure. You next insert a trocar into the rumen from the left flank and froth exits as shown in the photo. The pH of the froth is 6.2. You should now treat this cow with what drug to further relieve the bloat?
- Xylazine IV (1 mg/kg)
- Tetracycline IM or IV (label dose rate)
- Penicillin orally (10 million units)
- Oral sodium bicarbonate (1 gm/kg)
- Poloxalene orally (44 mg/kg)
Answer: Poloxalene orally (44 mg/kg)
Explanation
You need to treat with a substance to reduce the surface tension and destabilize the froth. The pH is within normal limits for rumen contents; therefore, oral bicarbonate is not beneficial. In a pinch, one could also use cooking oil to attempt to break down the foam.
To treat the cow’s frothy bloat, administer poloxalene orally at 44 mg/kg. This substance reduces surface tension, helping to destabilize and break down the foam. Since the rumen pH is normal at 6.2, oral bicarbonate is not useful. Cooking oil can be used as an alternative in emergencies.
A 5-day old dairy calf has decreased appetite and is depressed. On physical exam, you note that she has a temperature of 104F (40 C), HR 120, scleral injection, and one eye has cloudy material in the anterior chamber. Pending lab results, you make a tentative diagnosis of what condition?
- Chlamydia psittaci ocular infection and sepsis
- Pinkeye caused by Moraxella bovis
- Malignant catarrhal fever (MCF)
- Bovine viral diarrhea (BVD)
- Failure of passive transfer (FPT) and sepsis, with hypopyon
Answer: Failure of passive transfer (FPT) and sepsis, with hypopyon
Explanation
The history of a neonate with these signs and an elevated temperature, scleral injection and hypopyon are indicative of bacterial sepsis, a result of FPT.
A purebred Holstein breeder wishes to rid his dairy herd of Leptospira interrogans serovar Hardjo (type Hardjo-Bovis), which has been causing reproductive problems in his herd. Which steps are most likely to accomplish this goal?
- Treat all animals with tetracycline to eliminate carriers and regularly vaccinate all cattle against this serovar
- Regularly vaccinate all cattle and eradicate rodents, as they are the maintenance hosts of this serovar
- Regularly vaccinate all cattle and eliminate all dogs from the farm
- Treat all animals with dihydrostreptomycin
- Vaccinate all animals in the herd regularly
Answer: Treat all animals with tetracycline to eliminate carriers and regularly vaccinate all cattle against this serovar
Explanation
Since Hardjo-Bovis is carried by cattle, he needs to both treat and vaccinate. Vaccination can prevent new carriers, but will not eliminate existing carriers. To be cost effective, he may need to mass treat dry cows and young stock using long acting tetracycline.
Swine (and opossums, skunks and raccoons) are carriers of Pomona, dogs of Canicola, rats of Icterohemorrhagiae, swine, mice and horses of Bratislava, and raccoons, muskrats and squirrels of Grippotyphosa.
It is the middle of summer, and located in a pasture with a marshy area, several cattle are found dead. The only clinical sign observed by an employee was red urine. You perform a necropsy on one of the affected animals and notice that urine is dark red and all body fluids are icteric and hemorrhagic. There is evidence of hemorrhage in the abomasum and reticulum. Finally, the liver has an anemic infarct near the portal vein. What are these animals infected with?
- Anaplasma marginale
- Clostridium hemolyticum (Cl novyi type D)
- Leptospira pomona
- Salmonella typhimurium
Answer:
Explanation
The correct answer is Clostridium hemolyticum, now more properly called Cl novyi type D, which causes bacillary hemoglobinuria. The organism resides in the liver until anaerobic conditions develop, and then they start replicating and producing toxins. The finding of an anemic infarct on necropsy is classic for red water disease. Liver flukes are often associated with the disease, as they cause the anaerobic tracts needed for the organism to bloom. Marshy areas with snails are part of the liver fluke cycle of transmission.
Anaplasmosis is not a good answer choice because there is no hemoglobinuria associated with the disease. The same goes for Salmonella. Leptospirosis is a good differential given the history; however, necropsy findings are consistent with bacillary hemoglobinuria.
***PowerLecture: Flukes and Bacillary Hemoglobinuria
You are called to a dairy farm in the western United States because several cows are standing in the corral rather than eating with the others. They have been drooling and champing their mouths. The daughter’s horse is also affected. On physical exam of the cows you find their rectal temperatures to be elevated and that their tongues are ulcerated as shown in the photo, but there are no other lesions you can find on the feet or teats. You call the state and federal veterinarians and say that this looks most like a case of_______
- Contagious ecthyma (Orf)
- Foot and mouth disease (FMD)
- Vesicular stomatitis (VS)
- Woody tongue (actinobacillosis)
- Bovine papular stomatitis (BPS)
Answer: Vesicular stomatitis (VS)
Explanation
VS occurs as an epidemic about once every 7 to 10 years in the western US. It appears to be spread by insect vectors and then spreads by contact and fomites from cow to cow once clinical disease occurs. Horses can also be affected by this virus.
***PowerLecture: Vesicular Stomatitis
A beef ranch in the oak/brush foothills of California has experienced abortions in 40/200 of their new heifers, and the abortions are continuing. These heifers were purchased from Arizona. The fetuses appear to be about 6 to 7 months gestational age. You take several freshly-aborted fetuses (see image) to the diagnostic lab. The lesions they describe include enlarged superficial cervical lymph nodes, spleen, and liver. The thymus is slightly smaller than normal. Based on this information and the history that these animals were not locally raised, you make a tentative diagnosis of epizootic bovine abortion (EBA), also known as foothill abortion. The rancher asks you for information on how best to avoid this scenario again in the future. What is the best preventative strategy?
- Raise heifers in the foothills and put pregnant heifers in the hills only when 6 months or more pregnant
- Feed tetracycline to pregnant heifers for 9 months
- Vaccinate heifers against Chlamydia psittaci
- Put ear tags on all heifers to keep ticks off before putting the heifers in the foothills
- Provide hay periodically so that heifers do not eat oak
Answer: Raise heifers in the foothills and put pregnant heifers in the hills only when 6 months or more pregnant
Explanation
After decades of research, a novel deltaproteobacterium was identified as the causative agent of EBA in 2005.
The disease is transmitted by a ground-dwelling soft tick, Ornithodoros coriaceus. Abortion occurs more than 3 to 4 months after exposure, so keeping pregnant heifers out of the foothills until they are 6 months pregnant means they calve before fetal lesions occur. Raising heifers in the foothills until breeding does provide premunition immunity. Also, the rancher should keep these heifers that abort, as they will now be immune to EBA. Tick control is very difficult on cattle running in the hills, but the ticks do not inhabit irrigated pastures (they live in the dry ground duff of needles and leaves), so bred heifers can be kept in irrigated pastures for months 1-6 of pregnancy. Feeding tetracycline for 9 months is not practical. As of 2019, there is no commercially available vaccine. However, since 2009 the University of California at Davis has been doing field trials on a live bacteria vaccine that has shown promising efficacy.
A rancher in the Rocky Mountains has found that many of the beef calves born this season are deformed with cleft palates, arthrogryposis, and crooked spines. The pregnant cows were grazing on pastures that have had a large amount of several species of the plant pictured. What is the problem that caused these congenital anomalies?
- Locoweed
- Lupine
- Tansy ragwort
- Oleander
- Larkspur
Answer: Lupine
Explanation
Some lupines contain alkaloids called sparteine and anagyrine. Cows eating lupine during early gestation often give birth to calves with cleft palates, crooked legs and distorted/malformed spines. Six of the poisonous species implicated in “crooked calf disease” are silky lupine (L. sericeus), tailcup lupine (L. caudatus), velvet lupine (L. leucophyllus), silvery lupine (L. argenteus), lunara lupine (L. formosus), and yellow lupine (L. sulphureus).
You are called to investigate a beef cattle operation where several young adults (1-2 years of age) have developed acute, watery diarrhea (see image). One of the affected cows died and a necropsy reveals worms and petechiae in the abomasum. The wall of the abomasum has a nodular “cobblestone” appearance that is most severe in the fundic region. Which of the following agents is most likely?
- Trichostrongylus axei
- Ostertagia ostertagii
- Haemonchus placei
- Dictyocaulus viviparous
- Mecistocirrus digitatus
Answer: Ostertagia ostertagii
Explanation
This is a description of type Il ostertagiasis.
The other parasites listed could be differentials with the exception of Dictyocaulus which is a lungworm. The main reason that Ostertagia is the best answer is the description of the abomasum.
The cobblestone appearance which is also sometimes described as having a Moroccon leather appearance is essentially pathognomonic for Ostertagia. This occurs because Ostertagia larva undergo hypobiosis (larval inhibition) and lay dormant in the early fourth larval stage within the glands of the abomasum, forming the nodules.
They resume development and emerge seasonally leading to severe signs.
You have decided that you need to do an exploratory right flank surgery on a valuable cow because she has colic and abdominal distention, and is passing scant amounts of dark red feces. There are no obvious pings. She is dehydrated (skin turgor is abnormal and eyes sunken) and totally anorectic. The owner reports that she was normal two days ago when he last looked at her closely.
On exploratory surgery under local anesthesia you find a hard 6- to 8- inch long by 4-inch diameter mass in the small intestine, as shown in the photo. It is painful to the cow when it is touched. The bowel proximal to the mass is distended and the bowel distal is empty. How would you treat this?
- Euthanize the cow as this is an inoperable tumor
- Surgically reset the intussusception
- Perform a surgical bypass of the mass but do not remove it
- Close the cow and give antimicrobial drugs, laxatives and IV fluids
- Manually reduce the mass and close the cow
Answer: Surgically reset the intussusception
Explanation
Hopefully you will be able to recognize that the “mass” visualized in this image is an intussusception.
After removal, an end-to-end anastomosis of the intestine is performed, and the cow is aggressively treated with antimicrobial drugs and IV fluids with a good content of chloride, such as saline, since these animals are usually suffering from hypochloremic hypokalemic metabolic alkalosis.
***PowerLecture: Colic
This 3-year old Charolais cow in the picture presents with a 2-day history of not eating and looking uncomfortable and hunched up. There are no others in the herd affected. On physical exam, there is decreased rumen motility, a temperature of 105.2F or 40.7C, and a heart rate of 82 bpm. You perform a scooch test on the cow by firmly squeezing down over the withers. The test was positive (she refused to dip her back normally). What is your most likely diagnosis?
- Left displaced abomasum
- Bovine spongiform encephalopathy
- Grain overload
- Traumatic reticuloperitonitis
Answer: ** Traumatic reticuloperitonitis**
Explanation
This question provided a classic description of the presentation for TRP. The clinical signs can be vague and misleading, but the localization of xiphoid pain as shown with the scooch test is a strong indicator of TRP. With a positive scooch test, the cow will be stiff, reluctant to scooch down, and grunts may be heard. Sometimes the stethoscope needs to be placed over the trachea because the grunt may be soft. Additionally, the xiphoid region should be pushed up upon to see whether the cow reacts painfully. There is no mention of pinging that would indicate a displaced abomasum. Xiphoid pain would not be seen as a result of grain overload. Cows with bovine spongiform encephalopathy (mad cow disease) will show neurologic clinical signs such as hypermetric ataxia, hyperexcitability, and hyperesthesia.
**PowerLecture: Traumatic Reticuloperitonitis
You examine a group of sixty 4- to 7-month old dairy calves which appear small and thin. The owner says that in the last few weeks several have developed diarrhea and quit eating, and two have recently died. You note some sunburned white areas on the skin, all are thin, and several are very weak. You do a postmortem examination on the worst and find a small hard liver. The biopsy looks as shown in the photo with fibrosis, bile duct proliferation, and megalocytosis. What is your diagnosis?
- Black disease
- Oleander toxicity
- Mycotoxicosis
- Pyrrolizidine alkaloid toxicosis
- Gossypol toxicity
Answer: Pyrrolizidine alkaloid toxicosis
Explanation
PAs inhibit mitosis of hepatocytes, so they cannot multiply. As they age, they become large (megalocytes) and when they die they are replaced by fibrous tissue. Bile ducts proliferate as a nonspecific response to hepatic damage. You then look at some of the older alfalfa bales he was feeding to these calves and find loads of Senecio vulgaris, a PA containing plant.
Aflatoxins (a mycotoxin) from Aspergillus and other fungi can cause liver lesions that are similar, but most pathologists think that finding megalocytes is diagnostic for PA toxicity.
***PowerLecture: Hepatic Disorders
The diagnosis is pyrrolizidine alkaloid (PA) toxicosis. PAs inhibit hepatocyte mitosis, leading to large megalocytes, fibrosis, and bile duct proliferation. The calves likely consumed Senecio vulgaris, a PA-containing plant found in their alfalfa feed. While aflatoxins can cause similar liver lesions, megalocytes are considered diagnostic for PA toxicity.
Comprehensive Information on Pyrrolizidine Alkaloidosis in Animals
- Definitions:• Pyrrolizidine Alkaloidosis (PA): Chronic toxicosis leading to hepatic failure due to ingestion of toxic plants containing pyrrolizidine alkaloids.
- Causative Agents:• Plants: Senecio, Crotalaria, Heliotropium, Amsinckia, Echium, Cynoglossum, Trichodesma.
• Toxins: Pyrrolizidine alkaloids (e.g., jacobine, retrorsine, seneciphylline, monocrotaline). - Pathophysiology:• Absorption and Distribution: Absorbed via GI tract, distributed to liver via portal vein, also found in fetal tissues, milk, and eggs.
• Metabolism: Converted to pyrroles in the liver, causing cytotoxic effects, particularly in hepatocytes.
• Mechanism of Action: Pyrroles create DNA and nucleoprotein adducts, leading to antimitotic effects and megalocytosis, promoting hepatic neoplasms. - Clinical Findings:• Acute: Sudden death from hemorrhagic hepatic necrosis and visceral hemorrhages.
• Chronic: Loss of condition, anorexia, dullness, diarrhea, icterus, ascites, photosensitization, hepatic encephalopathy (head-pressing, wandering, aggressive behavior), pica.
• Lesions: Enlarged, hemorrhagic liver in acute cases; atrophied, fibrous, nodular liver in chronic cases. - Diagnosis:• Clinical Signs: Based on exposure history, clinical signs, and biochemical changes (elevated GGT, GDH).
• Laboratory Tests: Chemical analysis of blood for toxic metabolites, hepatic biopsy showing megalocytosis and fibrosis.
• Postmortem Examination: Histopathologic changes in liver, pulmonary, or renal tissues, hepatic tissue assays for pyrrolic metabolites. - Treatment:• Supportive Care: Hydration, managing photosensitization.
• Diet: High-carbohydrate rations to avoid protein-induced clinical signs.
• Prognosis: Poor for animals showing clinical signs; prevent further intake of toxic plants. - Control and Prevention:• Feed Management: Avoid feeding contaminated hay, silage, or pellets.
• Biological Control: Use of sheep for grazing control, biological agents like predator moths and flea beetles.
• Herbicide Application: Annual applications in spring to control toxic plants.
You have diagnosed nitrate poisoning in a group of yearling cattle which were grazing Sudan grass (see photo). Which of the following is the most effective treatment?
- Methylene blue
- Digitalis
- Vitamin B12
- Sodium thiosulfate
- Calcium gluconate
Answer: Methylene blue
Explanation
Nitrate toxicosis causes methemoglobinemia, in which the blood appears chocolate brown. As a result, the oxygen carrying capacity and delivery is greatly reduced and the animal may die. Methylene blue is usually administered IV as a 1% to 4% solution, with a total dose of 4 to 15 mg/kg body weight to cattle, for treating nitrate toxicosis.
Nitrates are found in high levels in many plants and some water sources. The nitrate is converted in the rumen to nitrite and then absorbed into the blood, which causes oxidation of the heme iron to the +3 ferric state (called methemoglobin). Methylene blue restores the iron in hemoglobin to its normal (reduced) oxygen-carrying state. This is achieved by providing an artificial electron acceptor for NADPH methemoglobin reductase (RBCs usually don’t have one; the presence of methylene blue allows the enzyme to function at normal levels).
The NADPH is generated via the hexose monophosphate shunt.
The most effective treatment for nitrate poisoning in cattle is intravenous administration of methylene blue. Nitrate toxicosis leads to methemoglobinemia, reducing oxygen-carrying capacity. Methylene blue, given as a 1-4% solution at 4-15 mg/kg, restores hemoglobin’s oxygen-carrying ability by acting as an artificial electron acceptor for NADPH methemoglobin reductase.
You are presented with a 10-day old Holstein dairy calf weighing 40 Kg that is cold (Temperature is 97 degrees F, 36.1 degrees C) and nonresponsive. Her eyes appear sunken as in the photo. In addition to placing the calf on a warming pad, what is the best treatment?
- 1 liter of subcutaneous fluids containing glucose, sodium, bicarbonate, chloride and lesser amounts of potassium
- 4 liters fluid containing equal amounts of sodium and chloride
- 4 liters of intravenous fluids containing glucose, sodium, bicarbonate, chloride and lesser amounts of potassium
- Gentamicin intravenously at the label dosage
Answer: 4 liters of intravenous fluids containing glucose, sodium, bicarbonate, chloride and lesser amounts of potassium
Explanation
The calf is in metabolic acidosis (base deficit of about 15) and needs sodium containing fluids IV that contain bicarbonate or other base. 4 liters intravenously is a more appropriate fluid volume for a dehydrated 10-day old calf, calculated as 10% Of the 40 kg body weight. The sunken eye, as seen in the photo, is an important indicator of marked dehydration.
To treat metabolic acidosis caused by loss of sodium containing fluids you need to give more sodium than chloride, so sodium bicarbonate is the fluid of choice. Neonates such as this one tend to develop severe metabolic acidosis as they dehydrate due to absorption of acids from the gut and due to loss of renal compensatory mechanisms due to poor renal perfusion. The calf is also likely to be hypoglycemic, so adding glucose is essential. As you rehydrate and bring up blood glucose, the serum potassium will be driven back into cells and needs to be replaced with some potassium in the fluids.
***PowerLecture: Calf Diarrhea Part 2
The best treatment for this 10-day-old dehydrated Holstein calf is 4 liters of intravenous fluids containing glucose, sodium, bicarbonate, chloride, and potassium. The calf is in metabolic acidosis with a base deficit of about 15, requiring sodium bicarbonate to correct the acidosis. Adding glucose helps address likely hypoglycemia, and potassium replenishment is essential as rehydration drives potassium back into cells.
Several beef cows present with a history of decreased appetite and excessive salivation. On physical exam, their tongues are firm on palpation, nodular, and painful (see image). You diagnose actinobacillosis. What is your recommendation to the owner?
- Begin therapy with an aminoglycosides
- Isolate affected animals and submit one of them for necropsy
- Isolate animals at once
- Change feed and treat
- Sell affected animals for meat
Answer: Change feed and treat.
The correct answer is to change feed and begin treatment of the animals affected with woody tongue, as the response is often good. Sodium iodide and antibiotics are effective. Given the presentation and clinical signs, these animals have probably begun to ingest very rough and stemmed (scabrous) feed items that have injured their mouths. Upon injury, the normal inhabitant Actinobacillus lignieresii invades the soft tissues and causes the characteristic woody tongue granulomatous inflammation.
These animals don’t have rabies, and there is no need to cull them. Change feed before additional animals are affected. Do not use aminoglycosides as they have an extremely long withdrawal period.
You are in charge of a slaughter house and are asked about why so many of the culled dairy cattle in a recent shipment have liver abscesses (see photo) and what can be done about it. The abscesses result in a significant financial loss for the owner because the liver is condemned, and he is concerned. What is the cause?
- Liver fluke migration
- Rumen acidosis
- Black disease
- Foot abscesses showering bacteria to the liver
- Traumatic reticuloperitonitis with hepatic involvement
Answer: Rumen Acidosis
Explanation
Dairy cattle which are fed a high concentrate diet should be gradually introduced to it. Even so, an additional dietary buffer may be needed. The herd veterinarian should check rumen pH on about 5 high-producing cows by needle stick of the rumen 2 to 3 hours after they are fed. If some fall below pH 5.5, additional sodium bicarbonate should be added to the ration.
The low rumen pH causes rumenitis allowing bacteria to translocate through the mucosa and be filtered from the hepatic portal circulation by the liver, resulting in one or more hepatic abscesses.
The key to picking rumenitis is that there are many culled dairy cattle coming in with this problem of hepatic abscess. If it were feet or hardware it would only occasionally lead to a liver abscess.
You examine a valuable beef bull which has been in a remote pasture unobserved for several months. The owner has noted that he has a swollen lower jaw. You note the hard, relatively non-painful swelling shown in the photo and diagnose:
- Tooth root abscess
- Osteosarcoma
- Lymphoma
- Actinobacillosis
- Actinomycosis
Answer: Actinomycosis
Explanation
Also known as lumpy jaw, this condition results from the entry of the normal rumen inhabitant Actinomyces bovis into the bony mandible (usual site) or maxilla through a break in the mucous membranes or teeth. It may be arrested with therapy using sodium iodide, antimicrobials or even isoniazid off-label, but the bony swelling seldom changes much, even if arrested.
- Actinomycosis: A chronic bacterial infection caused by gram-positive, anaerobic bacteria Actinomyces.
-
Causative Agents:
- Actinomyces bovis: Lumpy jaw in cattle.
- A. suis (A. denticolens): Pyogranulomatous mastitis in swine.
- A. hordeovulneris: Localized abscesses and systemic infections in dogs.
- A. viscosus: Cutaneous abscesses, pneumonia, pyothorax in dogs.
- Cattle: Slow-growing, firm mass attached to the mandible, facial distortion, loose teeth, dyspnea, ulceration, and fistulous tracts.
- Swine: Pyogranulomatous mastitis, subcutaneous granulomatous lesions, lung and organ abscesses.
- Dogs: Localized abscesses, pyogranulomatous pleuritis, peritonitis, and visceral abscesses.
- Methods: Clinical signs, culture (anaerobic conditions), Gram stain, radiology, cytology, and biopsy.
- Ruminants: Intravenous sodium iodide (70 mg/kg of a 10%-20% solution, repeated at 7-10 day intervals), with antimicrobials like penicillin, florfenicol, or oxytetracycline.
- Swine: Rarely successful; surgical removal may be required.
- Dogs: Surgical debridement, penicillin, cephalosporins, sulfonamides, and repeated chest drainage for pyothorax.
- Cattle: Avoid coarse, stemmy feeds or feeds with plant awns to prevent mucosal damage.
For more detailed information, visit the Merck Veterinary Manual - Actinomycosis in Cattle, Swine, and Other Animals.
Two 3 year-old bulls have died and another 5 are very ill with severe dyspnea and tachypnea. The affected animals are grunting, open-mouth breathing and frothing at the mouth. You are unable to catch one to check HR and rectal temperature or to listen to the chest.
The group of 20 animals was moved to a much better grass pasture 10 days ago. You perform a necropsy on one of the dead bulls and find that the lungs are edematous, emphysematous and full of bullae (see image). There is very little in the airways except froth, and no pleuritis is present. Based on the history and pathologic findings, you diagnose what disorder?
-Lungworm infestation
- Acute bovine pulmonary edema and emphysema
- Histophilus somni pneumonia
- Bovine respiratory syncitial virus
- Mannheimia hemolytica bronchopneumonia
Answer: Acute bovine pulmonary edema and emphysema
Explanation
This condition is an ARDS (acute respiratory distress syndrome) of cattle that usually occurs after animals are moved from poor quality feed to an improved lush pasture. The mechanism involves ingestion of L-tryptophan in lush feed being converted to 3-methylindole in the rumen. 3-MI is pneumotoxic and causes pulmonary edema, alveolar epithelial hyperplasia, hyaline membranes, and emphysema.
Lesions of the other choices are different from the ones described here. The two bacterial pneumonias usually occur in younger, often confined and stressed, animals. BRSV tends to affect young calves peracutely, and would not cause signs as described in these 3 year-old animals. Lungworm infestation could have similar clinical signs but is unlikely to be this acute and severe in 3 year-old animals, and parasitic pneumonia has a great deal of coughing associated with it. The pathology would be different with more consolidation and bronchial exudates.
Pulmonary Emphysema, Edema, and Interstitial Pneumonia in Cattle
Definitions and Causative Agents:
• Acute Bovine Pulmonary Emphysema and Edema (ABPEE): Also known as “fog fever”, caused by metabolites of L-tryptophan in lush pasture. • Pathogenesis: L-tryptophan is converted by ruminal microorganisms to 3-methylindole, which is pneumotoxic.
Clinical Changes and Symptoms:
• Symptoms: Mild to severe dyspnea, tachypnea, hyperpnea, mouth breathing, drooling, expiratory grunt, minimal coughing. • Lesions: Pulmonary edema, emphysema, alveolar epithelial hyperplasia, hyaline membrane formation.
Diagnosis:
• Assessment: History of pasture change, clinical signs, necropsy findings. • Histopathology: Congestion, alveolar edema, epithelial hyperplasia.
Treatment:
• No effective treatment: Manage affected animals with caution to prevent further stress and possible sudden death.
Prevention:
• Pasture Management: Gradual introduction to lush pastures, use of hay before grazing, strip grazing, grazing with less susceptible animals first. • Medications: Monensin or lasalocid to inhibit bacteria converting L-tryptophan to 3-methylindole.
For detailed information, visit the Merck Veterinary Manual - Pulmonary Emphysema, Edema, and Interstitial Pneumonia in Cattle.
A dairyman brings his prize 6-month old bull calf to your clinic because he is not eating all his feed today and has diarrhea. He has just purchased this registered bull calf from a neighboring state, and it was shipped a week ago during some very cold weather. You examine the bull calf and find T=104 F (40 C), HR=90, and RR=35, with poor rumen motility. There are several ulcers on the dental pad, and the diarrhea is foul-smelling and contains flecks of blood. The calf is hemorrhaging from small scleral blood vessels (see photo). You quickly take a blood sample and have your assistant run it to the state diagnostic lab, which calls you less than an hour later to say that the thrombocyte count is 5000 (normal is 100,000-800,000/ul). You tell the owner that the calf appears to have bovine virus diarrhea infection with thrombocytopenia. What should your first line of therapy be if you are to save this calf?
- Blood transfusion with fresh whole blood
- High doses of IV ceftiofur
- Immunostimulant drugs IV
- Antiviral drug therapy
- IV fluids to treat dehydration
Answer: Blood transfusion with fresh whole blood
Explanation
The thrombocytopenia is caused by BVD virus adhering to thrombocytes which are then removed by the reticuloendothelial (RE) system. Once the number gets this low, fatal hemorrhage is possible at any moment.
Although not usual, this form of BVD has been described. The other forms of therapy may be needed as well. If the calf survives, you will also need to determine whether or not he remains persistently infected with BVD… if he does, he should not be retained.
Comprehensive Information on Bovine Viral Diarrhea (BVD) for NAVLE Preparation
Definition & Etiology:
• Bovine Viral Diarrhea (BVD): A disease caused by Bovine viral diarrhea virus (BVDV), a Pestivirus in the Flaviviridae family. • Transmission: Mainly through direct contact with infected animals or contaminated fomites. Vertical transmission can lead to persistently infected (PI) calves.
Pathophysiology:
• BVDV can cause immunosuppression, leading to secondary infections. • Cerebellar Hypoplasia: In utero infection during mid-gestation can result in cerebellar hypoplasia in calves, characterized by ataxia, tremors, and inability to stand properly.
Clinical Signs:
• Diarrhea, fever, nasal discharge, immunosuppression, and mucosal disease in PI animals. • Neurological signs in calves with cerebellar hypoplasia include ataxia, intention tremors, and hypermetric gait.
Diagnosis:
• PCR and virus isolation are used to detect BVDV. • Serology to identify antibodies in the dam or calf.
Prevention:
• Vaccination: Prophylactic vaccination of breeding animals is essential to prevent vertical transmission and cerebellar hypoplasia in calves.
Treatment:
• No specific antiviral treatment; focus on supportive care and prevention of secondary infections.
