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
You visit a dairy that has ongoing problems with mastitis. They ask you for advice on proper milking and maintenance of equipment. Which of the following statements is INCORRECT?
- Shut off vacuum before removing the claw
- Replace the liner every 25 milkings
- Pre dip all teats
- Post dip all teats
- Fore strip each quarter
Answer: Replace the liner every 25 milkings
Explanation
The incorrect answer is to replace the liner after 25 milkings. This is the best answer because the liner will last for at least 500 milkings. There are three types of liners: synthetic rubber, natural rubber, and silicone. These are designed to last anywhere between 500 and 10,000 milkings. Post-milking teat disinfection is probably the most effective way of reducing the rate of contagious mastitis. Pre-milking dip will help control environmental mastitis.
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).
There are a number of drugs that are used extra label in beef cattle. When working with any food animal, you always have to consider milk and meat withdrawal. What is the meat withdrawal (in days) for xylazine, tolazoline, lidocaine, and meloxicam, respectively?
- 4, 8, 4, 15
- 15, 1, 8, 4
- 7, 18, 21, 15
- 3, 7, 3, 18
- 4,1, 18, 21
Answer: 4, 8, 4, 15
Explanation
The correct answer is 4, 8, 4, and 15. Remember that xylazine is extremely potent in cattle, taking 10% of the dose that would be given to a horse of equivalent size is sufficient.
Tolazoline is an alpha 2 antagonist. Give the same volume as xylazine. Lidocaine is commonly used during c-sections in cattle. If a producer is doing a c-section as a salvage procedure, it is important to inform that person that the cow cannot go to slaughter for 4 days.
Visit www.farad.org to search for this type of information.
Meloxicam is being used more and more. It is longer acting (~ 4 days) than banamine, but banamine only has 4 days of meat withdrawal. If you plan on going into production medicine, it is important to memorize the numbers for these commonly used drugs so that you can inform the producer.
A dairy has experienced an increase in abortions from midterm to term, as well as the birth of weak calves with neurologic signs. Based upon histopathologic lesions and herd serology, you have diagnosed Neospora caninum. Which of the following steps to help control the disease is most correct?
- Keep cats away from cows and cow feed
- Treat all cows in the herd with long acting tetracycline
- Depopulate and bring in clean seronegative cows
- Keep dogs and coyotes away from cows and cow feed Core Answer
- Keep raccoons away from cows and cow feed
Answer: Keep dogs and coyotes away from cows and cow feed
Explanation
The canine is the definitive host and sheds oocysts in the feces, which cause the disease when consumed by cattle. Like cattle, deer may also be infected as intermediate hosts. The dogs are initially infected by eating infected tissues from the cattle, most commonly an aborted fetus.
Which of the following is a characteristic often associated with bovine pyometra?
- Diarrhea
- High fever
- Polyuria/polydipsia
- Inappetence
- Marked abdominal pain
- Few if any overt signs
Answer: Few if any overt signs
Explanation
Unlike the bitch, who shows overt signs, including polydypsia, polyuria, inappetence, and sometimes high fever and diarrhea, the cow shows very few external signs of pyometra.
Cows localize the problem to the uterine lumen. Diagnosis in cows is obtained by transrectal palpation or transrectal ultrasonography.
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 submitted tissues from a dead dairy cow near a sheep feedlot that died 7 days after exhibiting clinical signs of corneal opacity, high fever, lymphadenopathy, and CNS signs. The lab reports that the brain has lymphocytic perivasculitis. Which of the following disorders is the most likely diagnosis?
- Polioencephalomalacia
- Bovine virus diarrhea virus (BVDV)
- Malignant catarrhal fever (MCF)
- Histophilus somni infection
- Grain overload (rumen acidosis)
Answer: Malignant catarrhal fever (MCF)
Explanation
Malignant catarrhal fever (MCF) in North America is caused by sheep-associated ovine herpesvirus-2. A very high percentage of sheep and goats in North America are infected with OHV-2 and can transmit the virus to susceptible cattle, bison, deer, and other related species, even if only in close proximity and not in direct contact. The virus causes lymphocytic vasculitis and can be fatal.
BVD does cause fever, but uncommonly results in corneal opacity. The marked lymphadenopathy and lymphocytic vasculitis are not consistent with BVD.
**PowerLecture: Malignant Catarrhal Fever - MCF
The owner of a new beef ranch on poor volcanic soil asks you to evaluate 2 steers. They are representative of an ongoing herd problem of chronic diarrhea and respiratory disease that is unresponsive to antibiotic treatment. On physical exam, you notice achromotrichia, ill thrift, and a temperature of 103F
(39.4 C) in both steers. You perform a transtracheal wash in one of the steers and it comes back positive for Pasteurella multocida. What is your diagnosis?
- Selenium deficiency
- Copper deficiency
- Pasteurella pneumonia
- Bovine viral diarrhea
Answer: Copper deficiency
Explanation
The correct answer is copper deficiency. The giveaway is achromotrichia or loss of hair color.
Dilution of the coat color is due to dysfunction of tyrosinase which converts L-tyrosine to melanin. In addition, copper deficient animals will have spontaneous fractures, secondary respiratory disease, diarrhea, ill thrift, decreased immunity, anemia, and poor reproduction. Selenium deficiency and BVD are actually pretty good differentials and if achromotrichia was not present either of those two are reasonable choices.
Molybdenum deficiency would not result in achromotrichia. On the other hand, if there had been excess molybdenum, then the Cu:Mo ratio would be off and copper deficiency could be observed.
Bleeding abomasal ulcers (sometimes called type 2 ulcers) have been diagnosed in a 2-year old dairy cow with melena and anemia. Which of the following treatments is contraindicated?
- Omeprazole
- Blood transfusion
- Flunixin meglumine
- Ranitidine
Answer: Flunixin meglumine
Explanation
Flunixin meglumine is contraindicated in this case. This drug (aka Banamine) is a non-steroidal anti-inflammatory drug (NSAID) and will only promote more ulceration because NSAIDs decrease mucosal blood flow. Blood transfusions are sometimes given if the bleeding is severe. Omeprazole (a hydrogen pump blocker) and ranitidine can be beneficial in calves and raise the abomasal pH, but not useful orally in adults. In adults, IV ranitidine can be used but is very expensive and reserved for high-value animals.
**PowerLecture: Abomasal Ulcers
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
Illness in young calves caused by Eimeria sp. is best treated with which of the following?
- Levamisole
- Ivermectin
- Amprolium
- Penicillin
- Tetracycline
Answer: Amprolium
Explanation
A number of drugs can be used to treat or prevent coccidiosis. The treatment dosage is generally higher but for fewer days than the preventive dosage. Monensin- and sulfa-containing drugs are also frequently used as treatments.
Bovine viral diarrhea virus and Border disease virus are small, enveloped RNA viruses that affect cattle and sheep respectively. What is another closely related pestivirus which affects swine and is of worldwide importance as a pathogen?
- Porcine Parvovirus
- Pseudorabies
- Classical swine fever
- Porcine Cytomegalovirus
- Swine Pox
Answer: Classical swine fever
Explanation
CSF, also known as hog cholera, is very closely related to BVD and Border Disease viruses. It is currently of major importance in Central and South America, Eastern Europe, and Southeast Asia.
***PowerLecture: Foreign Animal Diseases
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.
Which of these treatments is least effective for treating cyanide toxicity?
- Sodium nitrate
- Methylene blue
- Sodium thiosulfate
- Supplemental oxygen
Answer: Supplemental oxygen
Explanation
The answer is supplemental oxygen. Cyanide blocks cellular respiration and blocks oxidative transport. As a result, hemoglobin cannot release oxygen to the tissues and venous blood stays saturated with oxygen and is bright red. Supplemental oxygen is unlikely to change this. The other three options are the usual treatments for cyanide toxicity.
The least effective treatment for cyanide toxicity is supplemental oxygen. Cyanide blocks cellular respiration, preventing hemoglobin from releasing oxygen to tissues, causing venous blood to remain oxygen-saturated and bright red. Supplemental oxygen does not resolve this issue, while other treatments directly counter cyanide’s effects on cellular respiration.
Which of the following situations is most consistent with a diagnosis of Foot-and-Mouth disease?
- Cattle are affected with oral and foot lesions and horses are unaffected
- Horses are affected by foot lesions while cattle are affected with oral and foot lesions
- Sheep are not affected by the disease
- Horses and pigs will not be affected by the disease
- Both cattle and horses are equally affected with oral and foot lesions
Answer: Cattle are affected with oral and foot lesions and horses are unaffected
Explanation
The correct answer is cattle are affected with oral and foot lesions and horses are unaffected. Only cloven-hoofed animals are affected by FMD. Therefore, sheep and pigs are susceptible and horses remain unaffected.
If lesions are observed in swine, it is important to differentiate FMD from swine vesicular disease. In cattle, it is important to differentiate FMD from vesicular stomatitis, bovine papular stomatitis, pseudocowpox, and bluetongue. Another point is that sheep will not be affected by vesicular stomatitis.
The most consistent situation for Foot-and-Mouth Disease (FMD) is when cattle show oral and foot lesions while horses remain unaffected. FMD affects only cloven-hoofed animals, including cattle, sheep, and pigs, while horses are not susceptible. Differentiation from vesicular diseases in swine and cattle is essential for accurate diagnosis.
Comprehensive Information on Foot-and-Mouth Disease (FMD) in Animals
- Definitions:• Foot-and-Mouth Disease (FMD): A highly contagious viral disease affecting cloven-hoofed animals, causing vesicular lesions.
- Causative Agent:• Foot-and-Mouth Disease Virus (FMDV): An Aphthovirus from the family Picornaviridae with 7 serotypes: O, A, C, Asia 1, SAT 1, SAT 2, and SAT 3.
- Epidemiology and Transmission:• Hosts: Cattle, pigs, sheep, goats, and over 70 species of wild artiodactyls.
• Transmission: Direct contact, aerosolized particles, contaminated feed, fomites, and mechanical vectors.
• Geographical Distribution: Endemic in Africa, the Middle East, and Asia; eradicated from North America and Europe. - Pathophysiology:• Primary Infection Sites: Pharyngeal mucosa, respiratory tract, skin lesions.
• Viral Spread: Via lymphatic system, causing vesicle formation in the mouth, muzzle, teats, and feet. - Clinical Signs:• Cattle: Fever, vesicles in the mouth and on feet, drooling, lameness, weight loss, decreased milk yield, secondary bacterial infections.
• Pigs: Fever, lameness, vesicles on the feet and snout, lethargy, loss of appetite.
• Sheep/Goats: Largely inapparent; lameness, vesicles on feet and mouth.
• Young Animals: Myocarditis leading to sudden death without vesicular lesions. - Diagnosis:• Laboratory Tests: RT-PCR, virus isolation, serology, antigen ELISA.
• Samples: Vesicular epithelium or fluid, oropharyngeal fluid, serum. - Treatment:• No Specific Treatment: Supportive care in endemic regions.
- Control and Prevention:• Culling: In FMD-free regions to control outbreaks.
• Vaccination: Inactivated virus vaccines, particularly in endemic areas.
• Biosecurity Measures: Strict movement controls, disinfection, and rapid reporting of outbreaks.
Medications and Doses:
• Supportive Care: Fluids, antipyretics, antibiotics for secondary infections as necessary. • Vaccination: Regular booster doses based on regional epidemiology and serotype prevalence.
Summary:
• Causative Agent: Foot-and-Mouth Disease Virus (FMDV). • Symptoms: Vesicles, fever, drooling, lameness, myocarditis in young animals. • Diagnosis: RT-PCR, virus isolation, serology. • Treatment: Supportive care. • Control: Vaccination, culling in non-endemic areas, biosecurity measures.
At what age during gestation is a fetus most likely to become persistently infected with the noncytopathic form of bovine viral diarrhea?
- Fetus infected before 125 days of gestation
- Fetus infected at 320 days of gestation
- Fetus infected between 150-200 days of gestation
- Fetus infected between 200-270 days of gestation
Answer: Fetus infected before 125 days of gestation
Explanation
The correct answer is fetus infected before 125 days of gestation, with most of those occurring before 100 days.
A fetus infected with BVD at any time during gestation can be aborted or be a stillbirth. Most congenital defects associated with BVD occur when a fetus is infected between days 90-150 of gestation. Persistent infection of fetuses is seen when they are infected before 125 days of gestation. This is of importance because they have a potential to affect many other herdmates since they shed virus but may show no clinical signs. About half of the persistently infected calves will die during their first year of life. Clinical signs in BVD carriers vary greatly.
They may range from an asymptomatic animal to one that has diarrhea, fever, pneumonia, and oral ulcerations.
Additionally, you may have infected animals that are just repeat breeders. You may also see abortions, stillbirth, and congenital anomalies, The most co and congenital anomalies. The most common congenital anomaly associated with BVD is cerebellar hypoplasia, but there are many others.
**PowerPage: Bovine Viral Diarrhea
**PowerLecture: Bovine Viral Diarrhea
A fetus infected with the noncytopathic form of bovine viral diarrhea (BVD) before 125 days of gestation, particularly before 100 days, is most likely to become persistently infected. These fetuses shed the virus and may remain asymptomatic, but can infect herdmates. Persistent infection is significant due to potential transmission within the herd. Common congenital anomalies, like cerebellar hypoplasia, occur when infection happens between 90-150 days.
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.
Maple syrup urine disease is a genetic disorder associated with spongiform changes in the brain and caused by a deficiency of this enzyme in Hereford and polled Shorthorn calves. It usually shows up at 2 to 3 days of age. Which of the following enzymes is the correct one?
- Pyruvate kinase
- Branched-chain ketoacid decarboxylase
- Carnitine acyl translocase
- Acetyl-CoA carboxylase
Answer: Branched-chain ketoacid decarboxylase
Explanation
The correct answer is branched-chain ketoacid decarboxylase, which will cause accumulation of 2-keto-3-methylvaleric, 2-ketoisocaproic, and 2-isovaleric acids along with their precursors isoleucine, leucine, and valine.
These are excreted in the urine and result in a burnt maple syrup smell (hence the name of the disease). This hereditary disease causes an encephalopathy. Acetyl-CoA carboxylase turns acetyl-CoA into malonyl CoA in fatty acid synthesis. Carnitine acyl translocase helps bring fatty acids across the inner mitochondrial membrane for degradation. Pyruvate kinase turns phosphoenol-pyruvate into pyruvate in the glycolysis pathway.
Maple syrup urine disease is caused by a deficiency in the enzyme branched-chain ketoacid decarboxylase, leading to the accumulation of 2-keto-3-methylvaleric, 2-ketoisocaproic, and 2-isovaleric acids, along with their precursors isoleucine, leucine, and valine. This results in the characteristic burnt maple syrup smell in the urine and causes encephalopathy in affected Hereford and polled Shorthorn calves.
You arrive at a beef ranch in a mountain meadow at 5000 feet elevation in the western US because the owner has called with the complaint of sudden death losses in adult cows, and another one staggering. You examine the sick animal and find fever of 105F (40.6 C), elevated respiratory rate, HR of 100/min, icteric mucous membranes, and weakness. You collect a urine sample and it appears dark red (see image). You also perform a post-mortem on one of the recently dead cows and find a hepatic infarct, icteric tissues and hemoglobinuria. The owner asks for a diagnosis, treatment, and prevention.
- Blackleg; penicillin, vaccination
- Lightning strike; provide shelters with lightning rods
- Acute Fasciola hepatica infestation; penicillin, fluke control
- Bacillary hemoglobinuria; penicillin, vaccination, and fluke control
- Blue-green algae toxicity; no treatment, prevent via clean water source
Answer: Bacillary hemoglobinuria; penicillin, vaccination, and fluke control
Explanation
The diagnosis is bacillary hemoglobinuria caused by Clostridium novyi type D (formerly called Cl. hemolyticum).
Penicillin can be given to any animal showing early signs. Vaccination with Cl. novyi type D vaccine is effective, and prevention should also include fluke control. Migrating flukes cause hepatic damage and anaerobic areas which results in germination of the Cl. novyi spores in the liver, an infarct, and production of the hemotoxin.
Flukes are best controlled by controlling snails in wet areas, fencing off wet areas, and using routine fluke treatments.
The diagnosis is bacillary hemoglobinuria, caused by Clostridium novyi type D. Treatment includes administering penicillin to affected animals. Prevention involves vaccination with Cl. novyi type D and fluke control. Fluke migration creates anaerobic liver areas, allowing Cl. novyi spore germination, leading to hepatic infarcts and hemotoxin production. Controlling snails, fencing wet areas, and routine fluke treatments are essential preventive measures.
Bacillary Hemoglobinuria in Animals - Comprehensive Veterinary Information
Definitions and Terminology:
• Bacillary Hemoglobinuria (Red Water Disease): Acute toxemia caused by Clostridium haemolyticum.
Causative Agents:
• Pathogen: Clostridium haemolyticum (also known as Clostridium novyi Type D).
Physiopathology:
• Transmission: Ingestion of spores, which remain latent in the liver and germinate under anaerobic conditions caused by liver damage (e.g., liver fluke infestation). • Pathogenesis: Spores germinate in the liver, producing beta toxin (phospholipase C) that causes intravascular hemolysis, leading to hemolytic anemia and hemoglobinuria.
Clinical Findings:
• Symptoms: Sudden onset of severe depression, fever, abdominal pain, dyspnea, severe diarrhea, and hemoglobinuria. Anemia, jaundice, and edema of the sternum may also be present. • Lesions: Liver infarcts, bloody fluid in body cavities, hemorrhagic intestines, dark friable kidneys, and purplish red urine in the bladder.
Diagnosis:
• Clinical Signs: Port wine-colored urine, severe depression. • Postmortem: Liver infarcts with diagnostic confirmation via PCR, IFAT, or other laboratory tests.
Treatment:
• Antimicrobials: High-dose penicillin or tetracyclines. • Supportive Care: Blood transfusions and fluid therapy.
Control:
• Vaccination: With C. haemolyticum bacterin, given once or twice yearly. • Management: Control of liver fluke infestation and improved pasture drainage.
Which of the following is NOT a benefit of providing a DCAD (dietary cation-anion difference) diet to cattle?
- Cows absorb calcium more readily
- There is a lower incidence of milk fever
- Parathyroid hormone function is enhanced
- Cows remain relatively more alkalotic
Answer: *Cows remain relatively more alkalotic
Explanation
DCAD is used to help prevent milk fever. Cows eating a DCAD diet are actually more acidotic which enhances parathyroid hormone function along with a better ability to utilize dietary calcium. The easy measure is to check urine pH (it should be acid) on cows to be sure they are ingesting the diet.
To review, DCAD is dietary cation-anion difference. A DCAD diet is enhanced with more anionic salts containing the strong ions chloride and sulfur, and has decreased amounts of strong cations such as sodium and potassium.
A benefit of providing a DCAD diet to cattle is not that they remain more alkalotic; in fact, DCAD diets make cows slightly more acidotic. This enhances parathyroid hormone function and improves calcium utilization, helping to prevent milk fever. Urine pH should be monitored to confirm proper ingestion of the DCAD diet.
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 have submitted tissues from a dead dairy cow near a sheep feedlot that died 7 days after exhibiting clinical signs of corneal opacity, high fever, lymphadenopathy, and CNS signs. The lab reports that the brain has lymphocytic perivasculitis. Which of the following disorders is the most likely diagnosis?
- Bovine virus diarrhea virus (BVDV)
- Polioencephalomalacia
- Histophilus somni infection
- Grain overload (rumen acidosis)
- Malignant cataral fever (MCF)
Answer: Malignant cataral fever (MCF)
Explanation
Malignant catarrhal fever (MCF) in North America is caused by sheep-associated ovine herpesvirus-2. A very high percentage of sheep and goats in North America are infected with OHV-2 and can transmit the virus to susceptible cattle, bison, deer, and other related species, even if only in close proximity and not in direct contact. The virus causes lymphocytic vasculitis and can be fatal.
BVD does cause fever, but uncommonly results in corneal opacity. The marked lymphadenopathy and lymphocytic vasculitis are not consistent with BVD.
***PowerLecture: Malignant Catarrhal Fever - MCF
The most likely diagnosis is malignant catarrhal fever (MCF), caused by sheep-associated ovine herpesvirus-2 (OHV-2). This virus, common in sheep and goats, can transmit to cattle and cause fatal lymphocytic vasculitis. Key signs include corneal opacity, high fever, lymphadenopathy, and CNS symptoms. BVD is less likely as it rarely causes corneal opacity or marked lymphadenopathy.
Comprehensive Information on Malignant Catarrhal Fever (MCF) in Animals
- Definitions:• Malignant Catarrhal Fever (MCF): A severe, often fatal, lymphoproliferative disease in ruminants caused by ruminant gammaherpesviruses.
- Causative Agents:• Viruses: Ovine herpesvirus-2 (sheep), alcelaphine herpesvirus-1 (wildebeest), caprine herpesvirus-2 (goats).
- Epidemiology:• Hosts: Cattle, water buffalo, bison, deer.
• Transmission: Direct contact or aerosolized virus from carriers like sheep and wildebeest.
• Seasonality: Linked to lambing/calving periods; virus shedding is higher in young animals. - Clinical Signs:• Acute Cases: Fever, depression, oral/nasal erosions, lymphadenopathy, corneal opacity.
• Peracute Cases: Sudden death, hemorrhagic diarrhea, hematuria.
• Chronic Cases: Alopecia, weight loss. - Pathophysiology:• Infection Mechanism: Viral replication in lymphoid tissues leading to widespread vasculitis.
• Lesions: Necrosis and inflammation of mucosal epithelium, generalized lymphoid proliferation, vasculitis. - Diagnosis:• Clinical Signs: Fever, erosions, ocular changes, lymphadenopathy.
• Laboratory Tests: PCR, immunohistochemistry, serology.
• Differential Diagnoses: BVD, IBR, East Coast fever, rabies. - Treatment:• Supportive Care: No specific antiviral treatment; manage stress and secondary infections.
• Prognosis: Grave; high mortality rate. - Control and Prevention:• Biosecurity: Separate carriers (sheep, wildebeest) from susceptible species.
• No Vaccine: Early weaning and isolation of lambs.
Medications and Doses:
• Supportive Care: Antipyretics, fluids, antibiotics for secondary bacterial infections.
Summary:
• Causative Agents: Ruminant gammaherpesviruses. • Symptoms: Fever, nasal/oral erosions, lymphadenopathy, corneal opacity. • Clinical Changes: Vasculitis, necrosis, lymphoid proliferation. • Diagnosis: Clinical signs, PCR, serology. • Treatment: Supportive care. • Control: Biosecurity, no vaccine available.
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.
A 3-year old Holstein dairy cow, 3 weeks post partum, is presented with the complaint that she has dropped in milk production over the last several days. You perform a physical exam and the only abnormality you note is a large amount of ketone bodies in the milk and urine. You decide to administer glucose IV and insulin SQ. What else should this cow be administered?
- IM tetracycline
- Oral propylene glycol
- IM parathyroid hormone
- SQ bovine somatotropin
- IV calcium gluconate
Answer: Oral propylene glycol
Explanation
The oral propylene glycol will serve as a precursor for glucose production, and will help with the demands of lactation that are causing increased fat mobilization and ketosis. A fourth treatment that is sometimes used is corticosteroids, as they decrease milk production and increase gluconeogenesis.
***PowerPage: Ketosis
In addition to IV glucose and SQ insulin, the cow should receive oral propylene glycol. This acts as a glucose precursor, helping to meet the energy demands of lactation, reducing fat mobilization, and combating ketosis. Corticosteroids can also be used to decrease milk production and increase gluconeogenesis.
Mucosal disease, or alternatively, chronic Bovine Virus Diarrhea (BVD) occurs in cattle when:
- A 5-month old calf is infected with CPE biotype of BVD virus and then superinfected with a nonCPE biotype of BVD virus.
A 5-month old calf is persistently infected with a strain of BVD virus which coats platelets; platelets are then removed by the RE system resulting in a bleeding diathesis.
BVD type 2 infects a 5-month old calf.
A 5-month old calf which was persistently infected as a fetus with a non cytopathic (nonCPE) biotype of BVD virus is superinfected with a cytopathic (CPE) biotype of BVD due to rearranging of the parent non-CPE viral RNA.
A 5-month old calf which was persistently infected with the nonCPE biotype of BVD virus as a fetus forms antigen-antibody complexes which cause a fatal immune-mediated disorder.
Answer: A 5-month old calf which was persistently infected as a fetus with a non cytopathic (nonCPE) biotype of BVD virus is superinfected with a cytopathic (CPE) biotype of BVD due to rearranging of the parent non-CPE viral RNA.
Explanation
This is the correct answer because it describes the current understanding of the pathogenesis of both mucosal disease and chronic BVD.
A 5-month old calf is infected with CPE biotype of BVD virus and then superinfected with a nonCE biotype of BVD virus is incorrect because it does not say that there was persistent fetal infection; also, the order of the superinfection is the reverse of what causes mucosal disease or chronic BVD.
A 5-month old calf which was persistently infected with the nonCPE biotype of BVD virus as a fetus forms antigen-antibody complexes which cause a fatal immune-mediated disorder is incorrect because this is not the mechanism by which mucosal disease or chronic BVD occur.
All other answer choices are incorrect because they each describe one of the acute clinical syndromes from primary infection, rather than either mucosal disease or chronic BVD.
***PowerPage: Bovine Viral Diarrhea
Mucosal disease or chronic Bovine Virus Diarrhea (BVD) occurs when a 5-month-old calf, persistently infected as a fetus with the non-cytopathic (nonCPE) biotype of BVD virus, is superinfected with the cytopathic (CPE) biotype due to rearrangement of the parent non-CPE viral RNA. This describes the current pathogenesis of both mucosal disease and chronic BVD.
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.
During a visit to a dairy, several cows are noted to have 1-3 cm cysts on their backs with small holes at the center resembling breathing pores created by larvae. If these are breathing pores, what organism are the cows infected with?
- Simulium
- Anopheles
- Culicoides
- Sarcophaga
- Hypoderma
Answer: Hypoderma
Explanation
The correct answer is Hypoderma bovis or H lineatum. Hypoderma is also known as the cattle grub, heel fly, or warble fly. The life cycle begins with the female attaching up to 500 eggs to the hairs around the hocks and lower portions of the cow. First-stage larvae will hatch in just a few days and burrow into the skin. At this point, they begin their tour de cow and migrate towards the epidural fat in the spinal canal(H bovis) or via the esophagus (H lineatum). After several months in this beautiful location, they become L2s and migrate to the subcutaneous tissues of the back where they will molt once more, and become L3s. Once they are L3s, the swelling on the cows’ backs can be felt. After 5-11 weeks, the L3s mature and burst through the skin, dropping on the ground where they will become adults in another 1-3 months. Sarcophaga spp are known as the flesh flies. An adult female will deposit her eggs in wounds and ulcers; the larvae then feed off the wounds.
Eventually, they mature into L3s and fall off to pupate on the ground.
Simulium flies are also known as buffalo gnats or black flies. Adult females are the key problem with these flies because they suck blood! They prefer the legs, abdomen, head, and ears. Additionally, they will only eat during daytime. Female flies are an annoyance to cows and cause decreased productivity.
Anopheles are just mosquitoes; however, they are the most important vectors of human malaria and spread
West Nile Virus.
Culicoides are also known as no-see-ums, biting midges, and punkies. They are a great annoyance to cows and have the potential to transmit bluetongue and Onchocerca. In horses, they are thought to be the cause of sweet itch, a Type I hypersensitivity to their saliva.
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.
You perform an exam on a calf that was born with a twin. The calf has an enlarged clitoris and an abnormally small ano-genital distance. What is your diagnosis?
- Lupine toxicosis
- Negative energy balance
- Ponderosa pine needle toxicosi
- Freemartin
Answer: Freemartin
Explanation
The correct answer is that this calf is a freemartin. This is evident by the clinical signs provided. A freemartin results from in utero exposure of the female to Mullerian-inhibiting hormone (also called anti-mullerian hormone or AMH) being secreted by the male. She is exposed via anastomosis between the two fetuses’ chorioallantoic vessels. Lupine causes fetal arthrogryposis if ingested, and ponderosa pine needles induce late abortion if consumed.
Freemartin Heifer and Blood Types
Freemartinism in Cattle
Freemartinism is a condition of sterility observed in female cattle (heifers) that are born as twins to male calves. Approximately 92% of such heifers are sterile. This condition arises due to the vascular connections between the placentas of the twin fetuses, which allows the transfer of anti-Müllerian hormone from the male to the female fetus. This hormone inhibits the development of the female reproductive tract, leading to varying degrees of masculinization of the female genitalia.
Characteristics of Freemartin Heifers
• Genitalia: Affected heifers typically have a short vagina that ends blindly, without communication with the uterus. The cervix is often absent, and the ovaries usually remain underdeveloped and small. • Reproductive Organs: The tubular genital organs may range from cord-like structures to near-normal uterine horns, depending on the extent of masculinization.
Diagnostic Criteria
• Vaginal Length: In calves 1-4 weeks old, the normal vaginal length is 13-15 cm, whereas in freemartin heifers, it is about 5-6 cm. This can be measured by gently inserting a lubricated probe with a blunt end into the vagina. • Cytogenetic Examination: Freemartins typically exhibit a mix of XX and XY chromosome patterns due to the interchange of cells in the placental circulation between the fetuses. • Blood Types: Freemartinism can also be indicated by the presence of two different blood types in a single animal, reflecting the cellular exchange between the twin fetuses.
A beef cow presents for palpation at approximately 30 days of gestation. Which positive sign of pregnancy will be present?
- Chorioallantoic membrane slip
- Palpable uterine artery fremitus
- Placentomes are palpable
- Fetus is palpable
Answer: Chorioallantoic membrane slip
Explanation
The correct answer is chorioallantoic membrane slip. Placentomes will be palpable starting between 75-90 days of gestation. The fetus itself will be palpable beginning at approximately 60 days, but may be out of reach between months 4-7 of gestation. Uterine artery fremitus will be evident on the ipsilateral pregnant horn at about 120 days of gestation. From 7 months on, fremitus is palpable bilaterally. Fremitus does not necessarily indicate a viable pregnancy.
At approximately 30 days of gestation, the positive sign of pregnancy in a beef cow is the chorioallantoic membrane slip. Placentomes are palpable at 75-90 days, the fetus at 60 days, and uterine artery fremitus appears around 120 days, but fremitus doesn’t always indicate a viable pregnancy.
A necropsy of an aborted bovine fetus shows enlarged lymph nodes and spleen, destructive lesions to the thymus, and evidence of chronic granulomatous infection. What is the most likely cause of this abortion?
- Infectious bovine rhinotracheitis
- Brucellosis
- Tritrichomonas foetus
- Epizotic bovine abortion
Answer: Epizotic bovine abortion
Explanation
The correct answer is epizootic bovine abortion (EBA), also called foothill abortion. EBA is an important disease for beef producers in the foothill and mountainous regions of California, Northern Nevada and Southern Oregon. The lesions described in the question are consistent with this diagnosis. The etiologic agent of EBA is a bacteria, Pajaroellobacter abortibovis and the vector is a tick, Ornithodoros coriaceus.
Tritrichomona foetus is involved with early embryonic death.
Brucellosis abortions are rare since it has been almost completely eradicated from the U.S. Lesions include autolysis, placentitis, and bronchopneumonia.
Infectious Bovine Rhinotracheitis (IBR) causes rapid fetal death; therefore, there is very little time for fetal response. Lesions you are likely to see include autolysis and focal necrosis of the organs.
The most likely cause of this abortion is epizootic bovine abortion (EBA), also known as foothill abortion. EBA occurs in foothill and mountainous regions of California, Northern Nevada, and Southern Oregon. The lesions described, such as enlarged lymph nodes, spleen, and chronic granulomatous infection, are consistent with EBA, caused by Pajaroellobacter abortibovis and transmitted by the tick Ornithodoros coriaceus.
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 dihydrostreptomycin
- 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
- Vaccinate all animals in the herd regularly
- Treat all animals with tetracycline to eliminate carriers and regularly vaccinate all cattle against this serovar
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.
Leptospirosis in Animals - Comprehensive Veterinary Information
Definitions and Terminology:
• Leptospirosis: A zoonotic disease caused by pathogenic serovars of Leptospira.
Causative Agents:
• Pathogens: Leptospira interrogans, Leptospira borgpetersenii.
Physiopathology:
• Transmission: Direct or indirect contact with urine from infected animals, contaminated water, or soil. • Pathogenesis: Bacteria penetrate mucous membranes or broken skin, spread through the bloodstream, and localize in the kidneys, liver, lungs, and other organs.
Clinical Findings:
• Symptoms: Fever, anorexia, vomiting, dehydration, icterus, renal failure, hemolytic anemia, uveitis, abortion, stillbirths. • Lesions: Interstitial nephritis, hepatitis, pulmonary hemorrhage.
Diagnosis:
• Tests: Microscopic agglutination test (MAT), PCR, culture, ELISA. • Sample: Blood, urine, tissue samples.
Treatment:
• Antibiotics: Doxycycline, amoxicillin, penicillin. • Supportive Care: Fluids, blood transfusions.
Prevention:
• Vaccination: Polyvalent inactivated vaccines. • Hygiene: Avoid exposure to potentially contaminated environments.
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 dihydrostreptomycin
- 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
- Vaccinate all animals in the herd regularly
- Treat all animals with tetracycline to eliminate carriers and regularly vaccinate all cattle against this serovar
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.
Leptospirosis in Animals - Comprehensive Veterinary Information
Definitions and Terminology:
• Leptospirosis: A zoonotic disease caused by pathogenic serovars of Leptospira.
Causative Agents:
• Pathogens: Leptospira interrogans, Leptospira borgpetersenii.
Physiopathology:
• Transmission: Direct or indirect contact with urine from infected animals, contaminated water, or soil. • Pathogenesis: Bacteria penetrate mucous membranes or broken skin, spread through the bloodstream, and localize in the kidneys, liver, lungs, and other organs.
Clinical Findings:
• Symptoms: Fever, anorexia, vomiting, dehydration, icterus, renal failure, hemolytic anemia, uveitis, abortion, stillbirths. • Lesions: Interstitial nephritis, hepatitis, pulmonary hemorrhage.
Diagnosis:
• Tests: Microscopic agglutination test (MAT), PCR, culture, ELISA. • Sample: Blood, urine, tissue samples.
Treatment:
• Antibiotics: Doxycycline, amoxicillin, penicillin. • Supportive Care: Fluids, blood transfusions.
Prevention:
• Vaccination: Polyvalent inactivated vaccines. • Hygiene: Avoid exposure to potentially contaminated environments.
What is the effect of PGF2-alpha during anestrus in cattle?
- Induces an LH surge
- There is no effect
- Causes the lysis of the corpus luteum
- Induces FSH release
Answer: There is no effect
Explanation
The correct answer is that there is no effect when the cow is in anestrus. That is the problem with using PGF2-alpha to synchronize estrus cycles in cows. A mature corpus luteum is needed so that PGF2-alpha can lyse it; the cow goes back into estrus in about 2-5 days.
You are called out early in the morning to examine a recumbent 7-year-old Friesian cow which calved at some stage during the night and is now unable to rise with the abnormality seen in the picture. What should you do?
- Administer epidural anesthetic, remove attached fetal membranes, clean and lubricate the uterus and replace in normal position, then administer oxytocin and calcium gluconate
- Administer epidural anesthetic and excise the extruded tissue
- Administer epidural anesthetic, empty the bladder if necessary, lubricate the vagina and replace in normal position, place a Buhner suture around the vestibule at the point at which the initial eversion of the vaginal wall occurred
- Administer epidural anesthetic, reduce and retain the rectum with a purse-string suture that is loose enough to allow 2 fingers into the opening, administer fecal softeners
Answer: Administer epidural anesthetic, remove attached fetal membranes, clean and lubricate the uterus and replace in normal position, then administer oxytocin and calcium gluconate
Explanation
This is a case of uterine prolapse. Because images may sometimes be difficult to differentiate uterine versus other prolapses, the clinical history can be useful in helping differentiate which type of prolapse is likely. Uterine prolapse occurs immediately or within hours of parturition. Vaginal prolapse occurs primarily in late pregnancy.
Rectal prolapse is typically associated with straining to defecate.
The uterus is more easily replaced if the cow is standing. If she remains recumbent it may help to put her sternal and pull both hind legs into a position behind her.
The oxytocin will help involute the uterus and expel fluids, and the calcium gluconate will help treat or prevent hypocalcemia. Do not give oxytocin before replacing the uterus because this makes it turgid and much more difficult to replace. Although not mentioned in any of the answer choices, administration of an antibiotic (i.e. oxytetracycline) may be useful to reduce metritis.
If the cow remains down and unable to rise, she should be lifted using a flotation tank. The sooner this is done, the more likely she is to recover.
You are performing a routine pregnancy examination via rectal palpation on an Angus beef cow and note that placentomes of variable size, some as big as a half-dollar coin are present and also note bilateral uterine artery fremitus. At what point in gestation is the fetus?
- 60 days
- 5 months
- 35 days
- At least 6 months
- 4 months
Answer: At least 6 months
Explanation
The correct answer is at least 6 months. Placentomes (cotyledons on the placenta / caruncules on the uterus) will be palpable starting between 75-90 days of gestation and at 150 days can reach the size of a half-dollar coin. Three or more placentomes must be palpated to rule out that you are not palpating an ovary.
Uterine artery fremitus which is hypertrophy of the middle uterine artery with fluid turbulence that gives a “buzz” feeling to the artery will be evident on the ipsilateral pregnant horn at about 120 days of gestation. From 6-7 months on, the fremitus can be felt bilaterally. Fremitus is not a positive sign of pregnancy, but can be useful in staging.
You are asked to evaluate the breeding soundness of a 1-year old, 675 lb Brown Swiss bull. Vital parameters and your general physical examination are unremarkable. You collect semen via electro-ejaculation and note an acceptable semen quantity and quality. Scrotal circumference is 33 cm. You note 2 small penile warts near the tip of the penis that have a broad head and narrow stalk. There are no warts detected elsewhere on the bull and no other abnormalities associated with the penis. What should you recommend to the owner?
- The bull should not be bred because he has not yet reached puberty. Warts should be re-evaluated when the bull reaches puberty.
- You suggest vaccination with an autogenous vaccine
- The bull should not be bred until at least 6 months after regression of all warts
- Warts are not contagious but the bull has a very small scrotal circumference and is not considered a good breeding animal
- You suggest surgical removal and sexual rest for 2-3 weeks
Answer: You suggest surgical removal and sexual rest for 2-3 weeks
Explanation
Penile warts in young bulls are quite common and are caused by bovine papilloma virus-1 (BPV-1) which can also cause warts on the nose or teats. Warts are very contagious and primarily spread by contamination of facility equipment but also spread directly from bull to bull. BPV-1 infection is not associated with other health problems. The treatment of choice for penile warts is surgical removal. Surgical damage to the warts frequently stimulates an immune response against BPV-1. Healing is usually complete within 2-3 weeks.
Autogenous vaccines have been used to treat penile warts but this is rarely practiced now due to cost and risk of severe reactions and relatively little benefit compared to surgical removal. It is not necessary to wait 6 months before breeding. Bulls typically reach puberty at 9-11 months of age depending on breed. Scrotal circumference of a 1 year-old bull also varies by breed but >30 cm is typically recommended for breeding at this age.
The best recommendation is surgical removal of the penile warts, followed by 2-3 weeks of sexual rest. Penile warts in young bulls, caused by bovine papilloma virus-1 (BPV-1), are common and highly contagious. Surgical removal typically triggers an immune response, leading to complete healing within 2-3 weeks. Autogenous vaccines are rarely used due to cost and risk, and it’s unnecessary to delay breeding for six months. The scrotal circumference of 33 cm is acceptable for a 1-year-old bull, indicating readiness for breeding.
Which of the following is not a cause of teat lesions?
- Anaplasmosis
- Pseudocowpox
- Herpes mammillitis
- Vesicular stomatitis
- Bluetongue virus
Answer: Anaplasmosis
Explanation
The correct answer is Anaplasmosis, which is a cause of extravascular hemolysis. Pseudocowpox is a parapox virus and results in proliferative teat lesions. Vesicular stomatitis is a reportable disease caused by a rhabdovirus.
It is reportable because it is similar in presentation to foot and mouth disease. Clinical signs include ulceration of the teats and mouth. Bluetongue and herpes mammillitis also result in ulcerative lesions.
The 5-month old calf in the picture has diarrhea, fever and oral ulcers mainly on the dental pad. The calf entered a feedlot about 2 weeks before. Based on these clinical signs and history, the most likely diagnosis is ___________
- Bovine viral diarrhea (BVD)
- Infectious bovine rhinotracheitis (IBR)
- Vesicular stomatitis
- Heavy metal toxicity
- Contagious ecthyma
Answer: Bovine viral diarrhea (BVD)
Explanation
BVD typically causes clinical illness in young susceptible animals exposed and stressed through transport or crowding and can result in oral ulcerations.
**PowerPage: Bovine Viral Diarrhea
**PowerLecture: Bovine Viral Diarrhea
A valuable bull that has been heavily grain fed for show for over 3 months is found bleeding from the nose. You examine the animal and note a fever of 104 F(40 C), rapid respiratory rate, and HR of 90 beats/min. You tell the owner that this bull may have developed rumen acidosis in the past, a resulting liver abscess and has now developed_______
- Peracute Mannheimia hemolytica bronchopneumonia
- Bleeding diathesis due to clotting defect
- Bloody nose form trauma
- Bovine respiratory syncytial virus pneumonia
- Vena caval thrombosis and metastatic pneumonia
Answer: Vena caval thrombosis and metastatic pneumonia
Explanation
By chance a liver abscess in a few animals that develop rumen acidosis may form near the posterior vena cava and cause infected thrombi to break off and move down pulmonary arteries into the lung until they lodge and form an abscess. Pulmonary embolic abscesses then create tracts from affected arteries to an airway, which results in pulmonary bleeding. This condition is extremely difficult to treat successfully and animals usually die within months of a massive bleed.
A 3-year old Holstein dairy cow is one month fresh and the milker has noted that her production has dropped in the last week. On physical exam you find normal TPR, a gaunt abdomen, scant but normal-appearing feces, and no abnormalities on rectal exam. She has a prominent ping with variable changing pitch on the left side of the abdomen between the 10th and 13th ribs when simultaneous auscultation and percussion are used. The image shows a model of her abdominal organs viewed from the left side. What is the correct diagnosis?
- Free abdominal gas from uterine rupture
- Abomasal volvulus
- Gas in the rumen
- Left displaced abomasum
- Right displaced abomasum
Answer: Left displaced abomasum
Explanation
The gas-filled abomasum has moved from its normal position near the ventral midline to the left of the rumen, where it is trapped (see image). As gas bubbles in and out, it sounds like the end of a toilet flush. When percussed and auscultated, the changing gas pressures yield a variable high-pitched ping.
***PowerLecture: Left Displaced Abomasum
A dairyman calls to say he has lost several 5 week old calves to acute respiratory signs in the last week. The calves have fever, depressed attitude, decreased appetite, cough and nasal discharge. They do not seem to respond to antibiotic therapy and may die within a few days. On postmortem of one, you find the lungs fail to collapse when the thorax is opened (see image), and they have interstitial emphysema and a rubbery consistency. You believe this is most likely caused by Bovine Respiratory Syncytial Virus (BRSV). What should now be recommended for the herd?
- Vaccination of all calves against IBR
- Metaphyllaxis of all calves from birth with tetracycline IM every 3 days
- Intratracheal use of antiviral drugs in all affected calves
- Vaccination of all calves against BVD
- Vaccination of all calves against BRSV
Answer: Vaccination of all calves against BRSV
Explanation
Until the calves have time to develop immunity, new animals should be raised apart from and isolated from the current group of calves where the virus is circulating. Treatment of individual calves affected by BRSV may include antimicrobial drugs and NSAIDs; some veterinarians advocate the use of corticosteroids if pulmonary edema is severe.
A rancher’s favorite bull has a lesion in the interdigital area of the left front foot (see image). The bull has recently become slightly lame on the left front leg. You tell the rancher that it is a corn. The owner wants you to fix it. What treatment should you undertake?
- Tetracycline topically daily
- Inject 10% formalin into the lesion
- Procaine penicillin IM daily for 5 days
- Surgical removal using sedation and local anesthesia
- General anesthesia and careful dissection to surgically remove the mass
Answer: Surgical removal using sedation and local anesthesia
Explanation
The medical term for a corn is interdigital hyperplasia. Corns are thought to result from stretching of the insertions of the distal interphalangeal ligament in heavy beef breeds. In dairy breeds, corns can occur when cows are continuously standing in slurry, or have some other chronic source of irritation such as interdigital dermatitis.
Corns are best treated by surgical removal of the mass, being careful to avoid the interdigital fat pad. The area is then bandaged, and the claws can be temporarily wired together if necessary. Wiring the claws is often not necessary if the surgery is only skin deep.
A 6-year old dairy cow presents with a 1-week history of progressive abdominal distension and loss of body condition. The cow has had a poor appetite and appears anxious. On rectal exam, there is only scant feces that are hard fecal balls coated in mucus. The abdomen is markedly distended from “10 to 4 o’clock” when viewed from behind (see image). Temperature is 100.9 F (38.3 C), heart rate is 36 beats per minute, and respiratory rate is 24 breaths per minute. There is decreased force of rumen contractions occurring four times per minute. You pinch the cow’s withers and she lowers her withers normally. Passage of a stomach tube yields a small amount of gas. Ultrasound of the anterior abdomen is within normal limits (no abscesses seen). Abdominocentesis yields a small quantity of straw-colored fluid with low protein concentration and low numbers of cells, mainly lymphocytes and is considered within normal limits. What should you tell the farmer?
- The cow appears to have an impaction from Ostertagia or Haemonchus and should be treated with levamisole
- The cow appears to have free gas bloat and requires trocarization of the rumen and possible rumenotomy
- The cow appears to have vagal indigestion of undetermined cause and is unlikely to respond to medical management
- The cow appears to have frothy bloat and requires antifoaming agents
Answer: ** The cow appears to have vagal indigestion of undetermined cause and is unlikely to respond to medical management**
Explanation
This cow likely has vagal indigestion based on the chronicity and clinical appearance. Frothy bloat is typically much more acute. Due to the severity and chronicity of this cow’s signs, its prognosis should be considered poor even without determination of the specific underlying cause. Most cases of vagal indigestion require surgery to identify the underlying cause and medical management alone is usually ineffective.
This dairy cow in the picture presents for a decrease in appetite and milk production. You systematically do your physical exam and as you percuss and auscultate you hear a monotone “boink” on the left side, dorsally, approximately between rib spaces 9-13 and extending to the hip. What gas-filled organ are you hearing?
- Rumen
- Cecum
- Spiral colon
- Abomasum
Answer: Rumen
Explanation
The correct answer is rumen. The location extending up to the hip and the monotone “boink” (not ping) are indicative of the rumen. A cow with LDA would have a variable-pitched ping heard to only just in back of the last rib (not to the hip). It is variable because the rumen is usually still contracting medial to the displaced abomasum, and the changing gas pressures result in a pitch that changes during percussion and auscultation.
A 3-year old Holstein dairy cow is one month fresh and the milker has noted that her production has dropped in the last week. On physical exam you find normal TPR, a gaunt abdomen, scant but normal-appearing feces, and no abnormalities on rectal exam. She has a prominent ping with variable changing pitch on the left side of the abdomen between the 10th and 13th ribs when simultaneous auscultation and percussion are used. The image shows a model of her abdominal organs viewed from the left side. What is the correct diagnosis?
- Abomasal volvulus
- Gas in the rumen
- Free abdominal gas from uterine rupture
- Left displaced abomasum
- Right displaced abomasum
Answer: Left displaced abomasum
Explanation
The gas-filled abomasum has moved from its normal position near the ventral midline to the left of the rumen, where it is trapped (see image). As gas bubbles in and out, it sounds like the end of a toilet flush. When percussed and auscultated, the changing gas pressures yield a variable high-pitched ping.
***PowerLecture: Left Displaced Abomasum
A 10-day old commercial dairy calf has diarrhea that is white in color (see photo). The calf is dehydrated, hypovolemic, weak and unable to stand. T=10OF (37.8 C), HR=100, and RR=20. No other abnormalities are found on physical examination. Based on these findings, what is the treatment of choice?
- IV fluids containing only saline
- IV fluids with added sodium bicarbonate
- Oral fluids containing high levels of both sodium and chloride
- Oral fluids containing sodium bicarbonate
- IV fluids containing 50 meq/L of potassium
Answer: IV fluids with added sodium bicarbonate
Explanation
This calf is typical of those suffering from nonspecific calf diarrhea, most often associated with enteropathogenic E coli, rotavirus, or cryptosporidium. The calf develops hypovolemia and metabolic acidosis and requires sodium-containing IV fluids which contain additional alkali such as sodium bicarbonate.
One can assess that the calf is severely acidotic given that it is lethargic and unable to stand. While oral fluids may also be useful, at this stage, the calf will require IV fluids.
***PowerLecture: Calf Diarrhea Part 2
You are called out to see a 2-month old beef calf that collapsed this morning (see image). The farmer reports that the calf appeared well-nourished and was doing well a couple of days ago. You examine the calf and find temperature 100.6 F or 38.1 C, pulse 120 bpm, and respiratory rate 32 bpm with a slight expiratory grunt. The calf’s eyes are sunken and you estimate that it is 7-10% dehydrated based on decreased skin turgor. The ocular and oral mucous membranes appear congested. The abdomen is distended and palpation elicits a painful grunt. A quick field ultrasound shows several liters of peritoneal fluid and abdominocentesis yields blood tinged fluid. You quickly prepare the calf for a midline exploratory laparotomy and you identify a single, focal 1.5 cm perforating abomasal ulcer. With appropriate surgical and medical intervention, what is the calf’s prognosis?
- Grave (‹10% chance of survival and recovery)
- Good (80-90% chance of survival and recovery)
- Guarded (20-40% chance of survival and recovery)
- Fair (50-70% chance of survival and recovery)
- Excellent (>95% chance of survival and recovery)
Answer: Grave (‹10% chance of survival and recovery)
Explanation
This calf has an abomasal perforation and acute septic peritonitis based on the description. The prognosis is grave, even with prompt veterinary attention. The calf’s signs of dehydration, weakness, and expiratory grunt are additional poor prognostic indicators. Very few animals recover from diffuse peritonitis and those that do will have massive abdominal adhesions. Acute abomasal perforation through a single 1-2 cm ulcer occurs sporadically in young (2-4 month old) beef calves and the cause is unknown.
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?
- Perform a surgical bypass of the mass but do not remove it
- Close the cow and give antimicrobial drugs, laxatives and IV fluids
- Surgically resect the intussusception
- Manually reduce the mass and close the cow
- Euthanize the cow as this is an inoperable tumor
Answer: Surgically resect 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
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?
- Pulmonary stenosis
- Tetralogy of Fallot
- Ventricular septal defect
- Valvular endocarditis
- White muscle disease
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.
You are treating a very valuable 15-day old calf with total parenteral nutrition (TPN) because it had very severe diarrhea, weight loss, and anorexia (see image). You have already added glucose and amino acids to the TPN mixture. What other component must be added?
- Lactose
- Sucrose
- Vitamins
- Low-density lipoproteins
- Lipids
Answer: Lipids
Explanation
A typical TPN mixture for a calf this size would be 1L of 10% amino acids, 1L of 50% glucose and 500 ml of 10% lipids per day.
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?
- Malignant catarrhal fever (MCF)
- Failure of passive transfer (FPT) and sepsis, with hypopyon
- Chlamydia psittaci ocular infection and sepsis
- Pinkeye caused by Moraxella bovis
- Bovine viral diarrhea (BVD)
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 dairy farmer in California calls you in distress. He has just found 16 dead yearling Holstein heifers in a pasture near his home. There are no survivors. All 16 were observed yesterday and appeared normal. You perform a postmortem on two animals and find the plant pictured in the rumen. You walk out to look at his pasture and note that this plant is growing in the cemetery adjacent to his pasture, and you find a pile of clippings containing grass and the plant near the fence. What is the plant?
- Yew
- Skunk cabbage
- Oleander
- Locoweed
- Lupine
Answer: Yew
Explanation
Both Japanese yew (Taxus cuspidata) and English yew (T. baccata) contain alkaloids called taxines that are highly toxic and depress myocardial conduction by blocking sodium movement through membranes. Collapse and sudden death are commonly seen when this plant is ingested, often when clippings are consumed by livestock.
Oleander causes similar clinical scenarios.
A cow presents with a hard bony mass lesion at the ventral mandible (see image). Which treatment is known as being effective but is not recommended in pregnant animals as a result of concerns about it causing abortion and not for use in lactating dairy animals as a result of food safety issues?
- Oxytetracycline
- Intravenous sodium iodide
- Ceftiofur
- Corticosteroids
- Penicillins
Answer: Intravenous sodium iodide
Explanation
The correct answer is intravenous iodine. It is commercially available as a 20% solution at a dose of 15 ml/100 Ibs (66 mg/Kg). The clinical signs are suggestive of lumpy jaw, which is caused by Actinomyces bovis. The prognosis is poor, so most animals should be culled. Penicillins are reportedly successful at arresting the lesion in very early cases. However, there may be a better chance with intravenous 20% sodium iodide. That being said, due to concerns that iodide may cause abortion and because of food safety concerns, the label warns not to use sodium iodide in pregnant or lactating cattle. Ceftofur may not be used in this extra label fashion.
A 6-year old Friesian cow presents to you with a mass on the left mandible (see image). The farmer reports that the mass has developed over the last several weeks and the cow has recently had some difficulty eating and lost weight. On examination, the mass is firm, immobile, and painful on manipulation. You note a thick discharge with small granular particles. Based on the most likely diagnosis, what should you tell the farmer?
- The most effective treatment is oral sodium
iodide - Treatment is unlikely to be successful and the cow should be culled
- Treatment with sodium iodide intravenously is likely curative but the cow’s milk and meat will not be suitable for human consumption for 120 days
- Intravenous penicillins are likely to be effective
Answer: Treatment is unlikely to be successful and the cow should be culled
Explanation
This is a case of Actinomyces bovis or “lumpy jaw”.
The keys to the diagnosis are the firm mass that is immobile over the mandible. The presence of
“sulfur granules” in the discharge is also a characteristic finding with this disease.
Unfortunately, simply making the diagnosis is not sufficient to answer this question correctly. All of the answer choices are potential treatments for lumpy jaw but this represents a moderate to severe case which is unlikely to respond to treatment due to difficulty in achieving the necessary antibiotic concentration over a sustained period. Therefore, the best answer choice in this case is to cull the cow.
You are presented with a Holstein bull because he is not eating well. He has a normal temperature, HR=80 and RR=20. There is ventral abdominal edema (see image) and his breath smells like ammonia. Ultrasonography of the abdomen reveals free abdominal fluid and a collapsed urinary bladder. You suspect a ruptured bladder and urethra with secondary uroperitoneum due to a urolith in the urethra. Which of the following test results on blood are most useful in confirming your diagnosis?
- Hyponatremia, hypochloremia, hyperphosphatemia
- Azotemia, hypophosphatemia, hypernatremia
- Hyponatremia, hypokalemia, hyperchloremia
- Hypernatremia, hyperchloremia, hyperkalemia
Answer: Hyponatremia, hypochloremia, hyperphosphatemia
Explanation
These are the electrolyte abnormalities that should be expected in cases of uroabdomen. There would also be azotemia (elevated urea nitrogen), and possibly hyperkalemia in the blood.
***PowerLecture: Urolithiasis In Ruminants
The image demonstrates a sole abscess on the left rear medial claw of a commercial dairy cow which freshened one month previously. You plan to pare out the abscess and drain it. What additional step is most effective (and cost effective) to keep this cow in production while this problem resolves?
- Give IM penicillin for 5 days
- Apply wooden hoof block to affected left rear medial claw
- Soak the foot twice daily in hot Epsom salts and water for one hour
- Apply wooden hoof block to left rear lateral claw
- Give long acting tetracycline injection IM
Answer: Apply wooden hoof block to left rear lateral claw
Explanation
This is easy and inexpensive and gets the cow’s weight off the sore medial claw so she will ambulate and eat relatively normally.
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?
- IV fluids to treat dehydration
- Antiviral drug therapy
- High doses of IV ceftiofur
- Immunostimulant drugs IV
- Blood transfusion with fresh whole blood
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.
In January you examine a group of dairy calves which range in age from 2 to 7 months, with a complaint of hair loss and pruritus. The calves are thin and mucous membranes are pale. One has developed bronchopneumonia, and is also febrile and depressed. You do a skin scraping and find the parasite shown in the image, which your technician identifies as Solenopotes sp. The CBC shows the calves to be severely anemic. What treatment recommendation should you now make to the dairy owner?
- Treat all calves for mange
- Treat all calves with long acting tetracycline
- Treat all calves for lice
- Vaccinate all calves against Mannheimia hemolytica
- Treat all calves with hematinics
Answer: Treat all calves for lice
Explanation
This is a blood sucking genus of louse, and can cause severe anemia. The anemic calves become thin and more susceptible to diseases like pneumonia. You can tell this is a louse and not a tick or a mite because lice are insects with 6 legs and ticks and mites are arachnids with 8 legs.
The three genera of blood sucking cattle lice are Solenopotes, Linognathus, and Hematopinus.
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?
- AGID for BLV antibodies
- Lymphocyte count
- ELISA for BLV antibodies
- WBC count
- Aspirate lymph node and make slide
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.
A group of 3-4 month old dairy calves have oral ulcers and appear reluctant to eat hay because their mouths are sore. You examine 3 affected calves and find that they are of normal size and weight, have normal feces and normal TPR, but have ulcers around the dental pad and gums. The poor quality alfalfa hay contains some grass as shown in the photo. Based on these findings, what is the correct diagnosis?
- Actinobacillosis
- Bluetongue
- Water grass poisoning
- Bovine virus diarrhea
- Bristle grass (Setaria lutescens) irritation
Answer: Bristle grass (Setaria lutescens) irritation
Explanation
Yellow bristle grass contains sharp miniature barbs that stick into the mucosa of young cattle and horses and cause ulcers. Simple removal from the diet results in healing.
Which type of urolith occurs most commonly in western U.S. range cattle grazing mature grasses as shown in the photo?**
- Calcium oxalate
- Calcium carbonate
- Silicate
- Struvite
Answer: Silicate
Explanation
Silicate stones are the result of high intakes of silica in mature range grasses, combined with other factors such as dehydration. Struvites (ammonium, magnesium, and phosphate) tend to be found in feedlot animals receiving large amounts of grain. Calcium carbonate stones are most common in sheep grazing pastures high in calcium and oxalates.
This cow in the picture presents for chemosis and oculonasal mucopurulent discharge. On physical exam, you note her to be sneezing, febrile, and having small white fibrinonecrotic plaques on her conjunctival and nasal mucosa. What is your diagnosis?
- Moraxella bovis
- Infectious bovine rhinotracheitis
- Calici virus
- Mannheimia hemolytica
Answer: Infectious bovine rhinotracheitis
Explanation
The correct answer is infectious bovine rhinotracheitis. The key clinical sign to make this diagnosis is the white fibrinonecrotic plaques. None of the other answer choices cause white fibrinonecrotic plaques.
You are called early one cold spring morning to see a 5-year old dairy cow which is down in the corral. She freshened three days ago and is fed TMR. You find her to be barely responsive and unable to assume or maintain sternal recumbency, T=98F or 36.7 C, Hr=100/min and weak, and there is no rumen motility. The uterine lochia is red and mucoid. On rectal exam you find normal feces and a full bladder. How should you treat this cow?
- IV saline, large volumes
- Blood transfusion
- IV magnesium
- Broad spectrum antibiotics
- IV calcium
Answer: IV calcium
Explanation
This cow has the history and classic signs of hypocalcemia, also called milk fever. Skeletal, cardiac and smooth muscle weakness lead to the signs, and she is unable to maintain her body temperature in cold weather.
A large flock of sheep pastured on western US mountain rangeland has had several deaths and continues to have sick animals. The animals initially are observed to have ataxia and tremors, which progresses to lethargy, salivation, respiratory distress, bloating, and death. You visit the pasture to see what is occurring and perform a post-mortem on one animal. No significant gross lesions are found. The pasture seems to contain a great deal of lupine (see image), many species of which are known to contain toxic nicotinic-acting alkaloids such as quinolizidine alkaloids. The adjacent pasture contains the same plants and pregnant beef cows belonging to the same rancher. What should you tell him with regard to the cows?
- Pyrrolizidine alkaloids can damage the liver of cattle
- Expect cattle to develop bone marrow suppression and hemorrhage
- Lupine alkaloids can be teratogenic in cattle
- Cattle are likely to develop diarrhea if they consume lupine, but no other problems
- Cattle will show signs similar to the sheep, but have chocolate brown-colored blood
Answer: Lupine alkaloids can be teratogenic in cattle
Explanation
Different quinolizidine alkaloids in various species of lupine can cause either neurologic signs or teratogenesis.
Sheep are often more affected with neurologic signs by acute toxicity to lupine, although cattle and horses can also be affected. Cattle experience fetal teratogenesis more often than sheep. Classic lesions are arthrogryposis (crooked calf) or cleft palate. Some laboratories can assay for lupine alkaloids in urine or serum, so these can be collected to help confirm the diagnosis in the sheep.
Other plants with similar nicotinic-acting alkaloids include tobacco, Indian tobacco and tree tobacco, locoweeds, Scottish broom, mountain thermopsis, and poison hemlock. The best course of action is to move the animals to safer pastures.
Pyrrolizidine alkaloids are liver toxins and are not noted in this pasture. Bone marrow suppression occurs in cattle that consume large amounts of bracken fern. Brown-colored blood is associated with nitrate toxicity, which is associated with other plants.
You examine a 4-year old Holstein dairy cow that was a high producer for the first 2 months of the current lactation but has suddenly developed poor appetite and a markedly decreased milk production. On physical exam, you find temperature is 103.5F (39.7 C), HR=55, there is no rumen motility palpable or audible, and feces are scant. The cow has a papple shape when viewed from the rear (see image), with a slight “boink” hollow sound over the left flank. What is your tentative diagnosis?
- Cecal displacement
- Grain overload
- Abomasal torsion/volvulus
- Vagal indigestion
- Left displaced abomasum
Answer: Vagal indigestion
Explanation
The most common cause of vagal indigestion is a metallic foreign body penetrating the reticulum (hardware disease). The local peritonitis leads to poor motility of the forestomachs, so that the rumen fills with fluid and develops a gas cap, and the abomasum accumulates fluid; these give the shape from the rear of pear on the right and apple on the left (papple shape) as seen in the photo.
***PowerLecture: Vagal Indigestion
A 4-day old bull calf has been unable to bear weight on the right forelimb since birth which was an assisted delivery in anterior presentation using a calving aid. There is loss of muscle tone and markedly reduced reflexes in the right foreleg (see image). The right foreleg is non-painful on palpation. The left foreleg and the hindlimbs are weight bearing with normal reflexes. What should you tell the farmer?
- The calf appears to have a fracture of the distal third metacarpal growth plate due to traction at birth and has an excellent prognosis to improve with supportive care
- The calf appears to have a right brachial plexus avulsion due to traction at birth and it is unknown whether it will improve with time
- The calf appears to have right sided radial nerve paralysis due to traction at birth and prognosis for recovery is grave; the calf should be euthanized
- The calf appears to have a radius fracture from traction at birth and is likely to improve with splinting of the distal limb
Answer: The calf appears to have a right brachial plexus avulsion due to traction at birth and it is unknown whether it will improve with time
Explanation
The most likely conditions to consider for this calf are brachial plexus avulsion and radial nerve paralysis due to traction at birth. This injury results in an inability to extend the elbow, carpus and fetlock and bear weight on the affected limb with loss of muscle over the shoulder with resultant prominent spine of the shoulder blade. There is a dropped elbow, scuffing of the hooves as the leg is moved forward, and the foot is knuckled over at rest. Depending on the severity of injury, many calves can recover with supportive care. It is often recommended to carefully splint the distal limo to prevent contraction of the flexor tendons.
Other differentials could include spinal cord trauma or congenital sarcocystosis. Fractures are less likely given the presentation and lack of pain on palpation.
Several steers in a feedlot have interdigital lesions as shown in this image. They are lame and the lesion appears to be painful. You diagnose interdigital necrobacillosis or infectious footrot. Which of the following is the most effective feedlot treatment?
- Table all lame cattle and treat lesions with tetracycline bandages
- Florenicol SQ, one dose
- Chloramphenicol IM daily for 5 days
- Walk all cattle in the feedlot through a formalin footbath daily for 5 days
- Flunixin daily for 10 days
Answer: Florenicol SQ, one dose
Explanation
One dose of 40 mg/kg florenicol is reported to be an effective therapy and would be favored by a feedlot because the single treatment would avoid costly repeated handling. The use of
chloramphenicol is prohibited in cattle in the USA.
The image shows an infarct in the liver discovered on post mortem exam of a mature beef cow which died one hour before in a western mountain pasture, after being observed to appear normal one day earlier. There is also dark red urine in the bladder. The pasture contains native plants, some pine trees, and a marshy area with water plants. The cows are unvaccinated and were never wormed. Given this history and the lesion found, the most likely cause of death is
- Bacillary hemoglobinuria
- Blue-green algae toxicity
- Pine needle poisoning
- Viral hepatitis
- Death camas toxicity
Answer: Bacillary hemoglobinuria
Explanation
Also known as redwater, bacillary hemoglobinuria is caused by germination of Clostridium Novyi type D spores in the liver after anaerobic damage by migrating liver fluke larvae. Cl. Novyi was formerly called Cl. hemolyticum. Vaccination can prevent this disease.
***PowerLecture: Flukes and Bacillary Hemoglobinuria
A client brings the one-half inch grub shown in the image to you one spring day, telling you it emerged from a hole in the back of one of his prize show cattle. He wants to know what to treat his cattle with and when.
- Moxidectin now, in spring
- Ivermectin in February
- Ivermectin in early fall
- Thiabendazole in early fall
- Organophosphates in summer
Answer: Ivermectin in early fall
Explanation
This is a cattle warble called Hypoderma. The 2 species are H. bovis and H. lineatum. They undergo a long migration in tissues and only emerge from the back of the animal in spring. The crucial treatment time is early fall when larvae are just beginning to migrate in tissues. Organophosphates or one of the macrocyclic lactones (ivermectin, doramectin, eprinomectin or moxidectin) are effective.
