I85PREP
⌘ K
Eidgenössisches Examen Veterinärmedizin study materials
Eidgenössisches Examen Veterinärmedizin study resources

Eidgenössisches Examen Veterinärmedizin practice questions

One question at a time. Build your Eidgenössisches Examen Veterinärmedizin understanding.

First 50 of 190 questions. Each one lists the choices, the correct answer, and an explanation. The checker at the top of this page saves progress in this browser when it is available.

Continue in the practice tool above to load more questions, 50 at a time.

Question 1Companion-animal clinical reasoning and individual assessment

A 4-year-old male domestic shorthair cat presents with acute severe hindlimb paralysis, cold pulseless distal hindlimbs, cyanotic hind paw pads, and severe vocalization from pain. Femoral pulses are absent bilaterally. Thoracic radiography and echocardiography reveal severe hypertrophic cardiomyopathy (HCM) with left atrial enlargement (LA/Ao ratio = 2.1) and a 'smoke' spontaneous echocontrast in the left auricle. What life-threatening cardiovascular complication has occurred?

  1. Acute lumbar intervertebral disc extrusion (Hansen Type I IVDD)
  2. Bilateral femoral neck fracture
  3. Feline Aortic Thromboembolism (FATE / Saddle Thrombus / Aortenthrombose), caused by embolization of a left atrial thrombus into the aortic trifurcation Correct answer.
  4. Peripheral polyneuropathy caused by thiamine deficiency

Explanation

Feline Aortic Thromboembolism (FATE / Saddle Thrombus) is a catastrophic complication of feline cardiomyopathy (especially hypertrophic cardiomyopathy, HCM). Severe left atrial enlargement and blood stasis lead to thrombus formation in the left atrial appendage (auricle). Thromboemboli dislodge and lodge at the terminal aortic bifurcation ('saddle'), occluding iliac arteries and producing the classic '5 Ps': Pain, Paresis/Paralysis, Pulselessness, Pallor/cyanosis, and Polar (cold limbs). Emergency analgesia, antithrombotic therapy (clopidogrel, low-molecular-weight heparin), and congestive heart failure management are critical.

Question 2Companion-animal clinical reasoning and individual assessment

A 2-year-old male intact Doberman Pinscher presents with acute weakness, bloody diarrhea, and profuse vomiting. Complete blood count reveals severe panleukopenia (WBC 800/µL, absolute neutropenia 200/µL). Point-of-care fecal ELISA is strongly positive for Canine Parvovirus (CPV-2). What is the primary cellular target of canine parvovirus, and what is the main cause of rapid mortality in affected puppies?

  1. Parvovirus targets mature hepatocytes causing acute hepatic encephalopathy
  2. Parvovirus targets renal podocytes causing acute glomerulonephritis
  3. Parvovirus targets rapidly dividing cells (intestinal crypt enterocytes and bone marrow precursor cells), causing villous blunting/atrophy, destruction of the intestinal barrier, massive bacterial translocation, endotoxemia, and septic shock Correct answer.
  4. Parvovirus destroys alveolar type I pneumocytes causing severe pneumothorax

Explanation

Canine Parvovirus (CPV-2) is an un-enveloped single-stranded DNA virus with absolute tropism for rapidly replicating host cells in the S-phase of the cell cycle: 1) intestinal crypt epithelium (causing crypt necrosis, loss of villous architecture, severe malabsorptive hemorrhagic diarrhea); and 2) bone marrow myeloid and lymphoid precursors (causing profound leukopenia and panleukopenia). Loss of the intestinal mucosal barrier allows enteric Gram-negative bacteria to translocate into the bloodstream, leading to endotoxemia, sepsis, and DIC.

Question 3Companion-animal clinical reasoning and individual assessment

A 5-year-old male neutered Domestic Longhair cat presents with a 3-week history of polyuria, polydipsia, weight loss, and weakness with a plantigrade stance (walking on hocks). Fasting blood glucose is 22 mmol/L (reference 3.8–8.3 mmol/L), serum fructosamine is 520 µmol/L (reference <340 µmol/L), and urinalysis shows glucosuria without ketonuria. What type of diabetes mellitus is typical in cats, and what combination of diet and insulin is standard of care to achieve diabetic remission?

  1. Type 1 autoimmune absolute insulin deficiency; treated with high-carbohydrate grain diets and short-acting regular insulin
  2. Central diabetes insipidus; treated with desmopressin eye drops
  3. Feline Diabetes Mellitus resembles human Type 2 diabetes (characterized by peripheral insulin resistance and beta-cell glucotoxicity/amyloidosis); treated with an ultra-low-carbohydrate / high-protein diet combined with a long-acting insulin analogue (glargine or detemir) Correct answer.
  4. Renal glucosuria; treated with oral furosemide

Explanation

Feline Diabetes Mellitus is pathophysiologically analogous to human Type 2 diabetes, driven by obesity-induced peripheral insulin resistance, islet amyloid deposition (amylin), and beta-cell glucotoxicity. When diagnosed and managed early with an ultra-low-carbohydrate diet (<12% ME from carbs) and long-acting insulin (glargine or detemir), beta-cell glucotoxicity is reversed, enabling diabetic remission (cessation of insulin requirements) in up to 60–80% of feline patients.

Question 4Veterinary imaging, biomechanics and surgical planning

In diagnostic radiography of small animals, which contrast medium is strictly contraindicated for gastrointestinal imaging if perforation of the esophagus, stomach, or bowel is suspected?

  1. Non-ionic iodinated contrast (e.g., Iohexol / 碘海醇)
  2. Barium sulfate suspension (硫酸钡混悬液) Correct answer.
  3. Room air / Carbon dioxide negative contrast
  4. Sterile physiological saline

Explanation

Barium sulfate is an insoluble, non-absorbable heavy metal suspension. If gastrointestinal perforation is present, barium leakage into the mediastinum or peritoneal cavity causes severe, irreversible, foreign-body granulomatous peritonitis/mediastinitis with high mortality. Water-soluble iodinated agents (iohexol) must be used instead.

Question 5Veterinary imaging, biomechanics and surgical planning

In veterinary gastrointestinal surgery, which of the following suture patterns is an Inverting Suture (内翻缝合法) commonly used to close hollow visceral organs (stomach, uterus, bladder) to create a serosa-to-serosa leak-proof seal?

  1. Ford interlocking suture pattern (福特氏连续锁边缝合)
  2. Lembert suture pattern (伦伯特氏缝合法) Correct answer.
  3. Simple interrupted suture pattern (单纯间断缝合)
  4. Cruciate mattress suture pattern (十字褥式缝合)

Explanation

The Lembert suture (and Cushing/Connell/Halsted patterns) is an inverting suture pattern that turns the cut edges inward, bringing serosal surfaces into direct contact (serosa-to-serosa). Serosal contact promotes rapid fibrin sealing and watertight healing in hollow viscera.

Question 6Veterinary imaging, biomechanics and surgical planning

In small animal soft tissue surgery, what are the three anatomical components that define a True External Hernia (真性疝)?

  1. Hernial ring (orifice), Hernial sac (peritoneal lining), and Hernial contents (viscera/omentum) (疝环、疝囊与疝内容物) Correct answer.
  2. Hernial fissure, Fistula tract, and Granulation tissue
  3. Incarceration groove, Suture knot, and Abscess pocket
  4. Mesenteric root, Omental bursa, and Parietal pleura

Explanation

A true anatomical hernia consists of three classic structures: (1) The Hernial Ring (疝环 - the defect in the muscular/fascial abdominal wall), (2) The Hernial Sac (疝囊 - outpouching of parietal peritoneum and skin), and (3) The Hernial Contents (疝内容物 - displaced abdominal viscera, fat, or omentum).

Question 7Ruminant metabolism, herd evidence and reproductive health

A 5-year-old Swiss Fleckvieh dairy cow 3 weeks postpartum presents with a sudden drop in milk yield, ketonuria, selective anorexia (refusing concentrates but eating hay), and a hollowed left paralumbar fossa. Auscultation with simultaneous percussion over the left 9th to 12th rib intercostal spaces reveals a high-pitched, metallic resonant 'ping' sound. What is the definitive diagnosis and primary pathophysiology?

  1. Primary ruminal lactic acidosis with massive left-sided gas cap accumulation
  2. Left-Displaced Abomasum (LDA / Linksseitige Labmagenverlagerung) caused by abomasal atony, gas accumulation, and displacement dorsally and to the left between the rumen and the left abdominal wall Correct answer.
  3. Cecal dilatation and torsion displaced into the left hypochondriac region
  4. Traumatic reticuloperitonitis with localized gas-forming abscess formation in the omental bursa

Explanation

Left-Displaced Abomasum (LDA) typically occurs in high-yielding dairy cows during the early postpartum transition period. Postpartum metabolic stress, subclinical hypocalcemia, high-concentrate feeding, and decreased rumen fill lead to abomasal hypomotility, accumulation of volatile fatty acids and gas, and dorsal migration of the abomasum along the left body wall. The pathognomonic clinical finding is simultaneous auscultation and percussion ('pinging') in the left 9th–12th intercostal space.

Question 8Ruminant metabolism, herd evidence and reproductive health

A 3-year-old dairy heifer presents with bilateral blindness, head pressing, bruxism, opisthotonos, dorsomedial strabismus, and paddling convulsions. CSF analysis shows mild lymphocytic pleocytosis, and post-mortem brain examination under Wood's lamp (UV light at 365 nm) reveals autofluorescence of the cerebral cortex. What metabolic deficiency causes Polioencephalomalacia (Cerebrocortical Necrosis, CCN) in ruminants?

  1. Vitamin A deficiency causing optic nerve canal hyperostosis
  2. Selenium and Vitamin E deficiency causing nutritional muscular dystrophy
  3. Copper deficiency causing swayback/enzootic ataxia
  4. Thiamine (Vitamin B1) deficiency (or high sulfur/sulfate dietary intake causing mitochondrial respiratory chain inhibition) Correct answer.

Explanation

Polioencephalomalacia (PEM / Cerebrocortical Necrosis, CCN) is a severe neurological disease of ruminants caused by: 1) thiamine (Vitamin B1) deficiency (often secondary to ruminal acidosis altering microflora to produce bacterial thiaminases); 2) excessive dietary sulfur intake (producing neurotoxic hydrogen sulfide); or 3) amprolium toxicity. Lack of thiamine pyrophosphate impairs brain glucose metabolism, causing cerebral cortical laminar necrosis that autofluoresces under Wood's lamp. Prompt IV/IM thiamine administration is curative if given early.

Question 9Ruminant metabolism, herd evidence and reproductive health

A sheep flock in the Swiss Alps reports sudden deaths in several fattening lambs. Necropsy reveals severe bilateral symmetrical encephalomalacia of the basal ganglia, pulpy softened kidneys (Pulpy Kidney Disease / Breinierenkrankheit), glycosuria, and pericardial effusion with fibrin clots. What clostridial pathogen and toxin cause this condition?

  1. Clostridium tetani producing tetanospasmin
  2. Clostridium botulinum producing neurotoxin Type C
  3. Clostridium chauvoei causing Blackleg (Rauschbrand)
  4. Clostridium perfringens Type D producing Epsilon toxin (triggered by sudden carbohydrate-rich feed intake) Correct answer.

Explanation

Enterotoxemia (Pulpy Kidney Disease / Breinierenkrankheit) in sheep and goats is caused by Clostridium perfringens Type D, a normal inhabitant of the gut. When lambs experience sudden dietary changes (lush pasture, grain overfeeding), unabsorbed starch passes into the intestine, fueling massive clostridial overgrowth and production of pro-epsilon toxin, which is activated by trypsin into lethal Epsilon Toxin. Epsilon toxin causes vascular endothelial necrosis, blood-brain barrier disruption, focal symmetrical encephalomalacia, and rapid post-mortem autolysis of renal parenchyma ('pulpy kidney'). Vaccination with multivalent clostridial toxoids is preventive.

Question 10Swine population medicine, infection and production systems

During post-mortem inspection of market hogs, multiple white, fibrous, starlike spots are observed beneath the liver capsule ('milk spot liver' / 乳斑肝). Which parasite's larval migration through the hepatic parenchyma causes this pathognomonic lesion?

  1. Ascaris suum (猪蛔虫幼虫移行) Correct answer.
  2. Metastrongylus apri (猪后圆线虫)
  3. Stephanurus dentatus (猪肾虫)
  4. Oesophagostomum dentatum (猪结节线虫)

Explanation

When infective eggs of Ascaris suum (pig roundworm) hatch in the gut, L3 larvae penetrate the intestinal wall and migrate via the portal vein to the liver. Their destructive migration and resulting eosinophilic inflammatory fibrosis produce hallmark chronic white interstitial hepatitis patches termed 'milk spots' (乳斑肝).

Question 11Swine population medicine, infection and production systems

In the gross necropsy of a pig that died of Classical Swine Fever (CSF / 猪瘟), what hallmark pathological lesions in the ileocecal valve/colon and kidneys are pathognomonic?

  1. Button-like necrotic ulcers (纽扣状溃疡) in the large intestinal mucosa and petechial hemorrhages on the renal cortex ('turkey-egg' kidney / 麻雀蛋样肾) Correct answer.
  2. Large fibrinous pleuropneumonia and pleural adhesions
  3. Diffuse pseudomembrane on the tongue and vesicular erosions on the snout
  4. Chalky white muscle streaks and hepatic necrosis

Explanation

Button-like intestinal ulcers and renal petechiae are classic pathological associations of classical swine fever in the relevant differential. They are not present in every animal or exclusive proof of that infection. Similar serious diseases require appropriate laboratory confirmation, biosafety and the actual competent-authority response rather than a diagnosis by appearance alone.

Question 12Swine population medicine, infection and production systems

A pig breeding farm experiences widespread reproductive failure in pregnant sows (late-term abortions, mummified fetuses, stillbirths) along with severe interstitial pneumonia, eyelid edema, and blue-purple discoloration of the ears in nursery piglets ('Blue-Ear Disease' / 蓝耳病). What pathogen is responsible?

  1. Porcine Parvovirus (PPV / 猪细小病毒)
  2. Swine Influenza Virus (SIV / 猪流感病毒)
  3. Porcine Reproductive and Respiratory Syndrome Virus (PRRSV / 猪繁殖与呼吸综合征病毒 - Arteriviridae) Correct answer.
  4. Japanese Encephalitis Virus (JEV / 乙型脑炎病毒)

Explanation

The combined reproductive and respiratory herd pattern makes PRRS virus the most consistent listed cause in this teaching scenario. Clinical signs alone do not exclude other serious infections or coinfection. Representative testing and the relevant veterinary authority pathway are needed for a real herd event; no animal movement or vaccine programme is prescribed by this answer.

Question 13Equine clinical assessment, colic and locomotor problems

A 12-year-old pony gelding presents with recurrent laminitis, generalized hypertrichosis (hirsutism: long, curly hair coat that fails to shed), polyuria, polydipsia, muscle wasting over the dorsum, and bulging supraorbital fat pads. What is the definitive diagnostic test for Pituitary Pars Intermedia Dysfunction (PPID / Equine Cushing's Disease)?

  1. Baseline plasma Adrenocorticotropic Hormone (ACTH) concentration (evaluated against seasonally adjusted reference ranges) or the TRH Stimulation Test Correct answer.
  2. Single urine cortisol-to-creatinine ratio
  3. Oral glucose tolerance test alone
  4. Serum insulin-like growth factor 1 (IGF-1) assay

Explanation

Pituitary Pars Intermedia Dysfunction (PPID) in equids is caused by neurodegeneration of hypothalamic dopaminergic neurons, leading to loss of tonic inhibition and adenomatous hyperplasia of the pituitary pars intermedia with hypersecretion of ACTH, alpha-MSH, and CLIP. Diagnosis is confirmed by measuring resting plasma ACTH concentration (using seasonally adjusted reference intervals, as ACTH rises naturally in autumn) or by performing the Thyrotropin-Releasing Hormone (TRH) stimulation test (measuring ACTH 10 and 30 min post-TRH). Treatment is the dopamine agonist pergolide mesylate.

Question 14Equine clinical assessment, colic and locomotor problems

A 4-year-old Thoroughbred racehorse presents with acute epistaxis (bilateral frank blood dripping from nostrils) following a high-speed gallop. Tracheobronchoscopy performed 60 minutes post-exercise reveals blood in the trachea and mainstem bronchi originating from the caudodorsal lung lobes. What is the diagnosis, and what physiological mechanism causes Exercise-Induced Pulmonary Hemorrhage (EIPH)?

  1. Exercise-Induced Pulmonary Hemorrhage (EIPH); caused by extremely high pulmonary capillary transmural pressures (>75–100 mmHg) during strenuous exercise leading to stress failure of alveolar-capillary membranes Correct answer.
  2. Guttural pouch mycosis with internal carotid artery erosion
  3. Ethmoid hematoma involving the nasal turbinates
  4. Foreign body aspiration into the right mainstem bronchus

Explanation

Exercise-Induced Pulmonary Hemorrhage (EIPH) affects up to 70–90% of racehorses. During maximal exercise, equine cardiac output increases over 8-fold while pulmonary vascular resistance remains relatively high, driving pulmonary capillary transmural pressures above 75–100 mmHg. This extreme mechanical stress causes mechanical 'stress failure' and rupture of the thin pulmonary blood-gas barrier, particularly in the dorsocaudal lung lobes, resulting in alveolar hemorrhage. Endoscopic visualization of tracheal blood is the diagnostic gold standard.

Question 15Veterinary pathology, specimens and interpretation

In the cardiac conduction system of domestic mammals, which specialized myocardial cells are located in the subendocardium and conduct electrical action potentials at the highest velocity to coordinate rapid ventricular contraction?

  1. Sinoatrial node cells (窦房结细胞)
  2. Atrioventricular node cells (房室结细胞)
  3. Purkinje fibers (浦肯野纤维) Correct answer.
  4. Working ventricular myocytes (心室工作肌细胞)

Explanation

Purkinje fibers (浦肯野纤维) are modified cardiac muscle cells with large diameters, abundant glycogen, fewer myofibrils, and extensive gap junctions. They possess the highest conduction velocity (approx. 2–4 m/s) in the heart, ensuring synchronous depolarisation and contraction of both ventricles.

Question 16Veterinary pathology, specimens and interpretation

In mammalian renal physiology, what is the primary driving force that favors the filtration of plasma fluid across the glomerular capillary wall into Bowman's space?

  1. Bowman's capsule hydrostatic pressure (肾小囊流体静压)
  2. Plasma colloid osmotic pressure (血浆胶体渗透压)
  3. Glomerular capillary hydrostatic pressure (肾小球毛细血管流体静压) Correct answer.
  4. Renal medullary interstitial hyperosmolarity (肾髓质组织间隙高渗)

Explanation

Glomerular capillary hydrostatic pressure (PGC, approx. 45–60 mmHg in mammals) is the primary forward force promoting ultrafiltration. Bowman's capsule hydrostatic pressure and plasma colloid osmotic pressure oppose filtration.

Question 17Veterinary pathology, specimens and interpretation

According to the Frank-Starling Law of the Heart (心脏斯塔林定律), what intrinsic hemodynamic factor directly increases ventricular stroke volume during the subsequent cardiac cycle?

  1. Increased ventricular end-diastolic volume / preload (心室舒张末期容量 / 前负荷增加) Correct answer.
  2. Increased systemic arterial resistance / afterload (系统动脉阻力 / 后负荷增加)
  3. Decreased cardiac venous return (静脉回心血量减少)
  4. Selective stimulation of cardiac muscarinic M2 receptors (心肌M2受体选择性兴奋)

Explanation

The Frank-Starling mechanism states that greater ventricular filling during diastole (increased end-diastolic volume/preload) stretches myocardial sarcomeres toward their optimal length, thereby increasing the force of contraction and resulting stroke volume.

Question 18Veterinary epidemiology, zoonoses and food-chain protection

In veterinary epidemiology, what is the definition of Vertical Transmission (垂直传播) of an animal infectious disease?

  1. Transmission between animals of the same herd via aerosol droplets
  2. Mechanical transfer of pathogens between farms on truck tires
  3. Biological transmission through biting arthropod vectors
  4. Transmission of a pathogen directly from a maternal parent to its offspring via transovarial, transplacental, or colostral/perinatal pathways (病原体由母体经卵、胎盘或产道/初乳直接传给后代) Correct answer.

Explanation

Vertical transmission (垂直传播) refers to the direct transmission of infectious pathogens from parent (primarily female) to offspring during reproduction: via ovum (transovarial in poultry, e.g., Salmonella Pullorum), placenta (transplacental, e.g., PRRSV, BVDV), birth canal, or colostrum.

Question 19Veterinary epidemiology, zoonoses and food-chain protection

In veterinary parasitology and public health, which animal species serves as the ONLY definitive host (终末宿主) for Toxoplasma gondii (刚地弓形虫), capable of shedding environmentally resistant oocysts in feces?

  1. Dogs and wild Canidae species
  2. Domestic cats and other Felidae family members (家猫及其他猫科动物) Correct answer.
  3. Swine and domestic boars
  4. Sheep, goats, and cattle

Explanation

Members of the cat family (Felidae) are the sole definitive hosts of Toxoplasma gondii. Only in feline intestinal enterocytes does the sexual cycle (gametogony and oocyst formation) take place, shedding millions of unsporulated oocysts in cat feces.

Question 20Veterinary epidemiology, zoonoses and food-chain protection

What is the mandatory obligate intermediate host (中间宿主) in the lifecycle of the common liver fluke, Fasciola hepatica (肝片吸虫), that infects cattle, sheep, and humans?

  1. Oribatid pasture mites (地螨)
  2. Biting midges (Culicoides spp. / 库蠓)
  3. Freshwater mud snails (Lymnaeidae family, e.g., Galba pervia / 椎实螺 / 截口土蜗) Correct answer.
  4. Coprophagous dung beetles (蜣螂)

Explanation

Fasciola hepatica requires freshwater snails of the family Lymnaeidae (notably Galba pervia / Lymnaea truncatula) as intermediate hosts. Miracidia penetrate snails, developing through sporocyst, redia, and cercaria stages before encysting as metacercariae on pasture vegetation.

Question 21Species-aware pharmacology, anesthesia and welfare

What is the primary antimicrobial mechanism of action of beta-lactam antibiotics (beta-内酰胺类抗生素), such as penicillins and cephalosporins, against susceptible bacteria?

  1. Inhibition of penicillin-binding proteins (PBPs) interfering with bacterial peptidoglycan cell wall cross-linking (抑制青霉素结合蛋白，阻碍细胞壁肽聚糖交联) Correct answer.
  2. Binding to the 30S ribosomal subunit to cause mRNA misreading
  3. Inhibition of DNA topoisomerase II (DNA gyrase) preventing DNA replication
  4. Disruption of cytoplasmic membrane phospholipids causing ion leakage

Explanation

Beta-lactam antibiotics (penicillins, ampicillin, cephalosporins) are bactericidal drugs that bind to and inhibit penicillin-binding proteins (PBPs/transpeptidases), preventing the cross-linking of peptidoglycan polymers in the bacterial cell wall, leading to cell lysis under osmotic pressure.

Question 22Species-aware pharmacology, anesthesia and welfare

Which of the following adverse effect profiles is most characteristically associated with aminoglycoside antibiotics (氨基糖苷类抗生素, e.g., gentamicin, kanamycin, amikacin) in domestic animals?

  1. Aplastic anemia and bone marrow suppression
  2. Articular cartilage erosion in immature growing animals
  3. Nephrotoxicity and ototoxicity / vestibulocochlear damage (肾毒性与耳毒性) Correct answer.
  4. Esophageal stricture in feline patients

Explanation

Aminoglycosides (gentamicin, amikacin, streptomycin) accumulate in renal proximal tubular cells and endolymph/perilymph of the inner ear, causing acute tubular necrosis (nephrotoxicity) and irreversible auditory/vestibular hair cell damage (ototoxicity).

Question 23Species-aware pharmacology, anesthesia and welfare

Ivermectin (伊维菌素) exhibits high safety in most livestock but can cause severe neurotoxicity (ataxia, tremors, coma) in Collies and related breeds. What is the underlying pharmacological and genetic mechanism of this toxicity?

  1. Deficiency of renal glucose-6-phosphatase enzyme
  2. A deletion mutation in the ABCB1 (MDR1) gene resulting in deficient P-glycoprotein efflux pump expression at the blood-brain barrier (ABCB1/MDR1基因突变导致血脑屏障P-糖蛋白缺失) Correct answer.
  3. Overexpression of hepatic cytochrome P450 3A4 enzymes
  4. Inhibition of acetylcholinesterase at the neuromuscular junction

Explanation

In Collies and Australian Shepherds, a 4-bp deletion mutation in the ABCB1 (MDR1) gene results in non-functional P-glycoprotein. Without P-glycoprotein to pump ivermectin out of the brain, the drug crosses the blood-brain barrier in high concentrations and binds to neuronal GABA receptors, causing CNS depression, tremors, and coma.

Question 24Companion-animal clinical reasoning and individual assessment

A 6-year-old male neutered German Shepherd presents with chronic small-bowel diarrhea, profound weight loss despite voracious appetite (polyphagia), coprophagia, and poor hair coat. Feces are pale, voluminous, greasy, and clay-colored (steatorrhea). Serum cobalamin (Vitamin B12) is severely decreased (95 pmol/L) and serum canine Trypsin-Like Immunoreactivity (cTLI) is 1.2 µg/L (reference > 5.0 µg/L). What is the definitive diagnosis and primary therapy?

  1. Primary hypoadrenocorticism; treated with fludrocortisone
  2. Protein-losing nephropathy; treated with benazepril
  3. Exocrine Pancreatic Insufficiency (EPI / Exokrine Pankreasinsuffizienz), caused by pancreatic acinar atrophy; treated with lifelong dietary pancreatic enzyme replacement (pancreatin) and parenteral cyanocobalamin supplementation Correct answer.
  4. Giardiasis; treated with fenbendazole for 3 days

Explanation

Canine Exocrine Pancreatic Insufficiency (EPI) in German Shepherds is typically caused by autoimmune Pancreatic Acinar Atrophy (PAA). Loss of >90% of acinar digestive enzyme capacity leads to severe maldigestion, steatorrhea, polyphagia, and severe weight loss. The gold standard diagnostic test is serum canine Trypsin-Like Immunoreactivity (cTLI < 2.5 µg/L). Because the exocrine pancreas is the sole source of intrinsic factor in dogs, secondary severe cobalamin (B12) deficiency is universal. Lifelong pancreatic enzyme supplementation and parenteral B12 injections are curative.

Question 25Companion-animal clinical reasoning and individual assessment

A 2-year-old male Domestic Shorthair outdoor cat presents in summer with acute lethargy, high fever (40.2°C), severe regenerative anemia (PCV 12%), icterus, and splenomegaly. Blood smear examination stained with Wright-Giemsa reveals small, epicellular, basophilic coccoid and ring-shaped organisms adhering to the external surface of erythrocytes. What infectious hemotrophic mycoplasma is causing Feline Infectious Anemia (FIA)?

  1. Cytauxzoon felis
  2. Ehrlichia canis
  3. Mycoplasma haemofelis (formerly Haemobartonella felis) Correct answer.
  4. Bartonella henselae

Explanation

Feline Infectious Anemia (FIA / Hemotrophic Mycoplasmosis) is caused by Mycoplasma haemofelis, an unculturable cell wall-less bacterium that attaches to the outer surface of feline erythrocytes. Immune-mediated destruction of antibody-coated red cells by the splenic mononuclear phagocyte system produces severe, acute hemolytic anemia, icterus, and fever. Transmission occurs via cat bites, flea infestation (Ctenocephalides felis), or transplacental routes. Treatment requires doxycycline (5 mg/kg PO q12h for 14–21 days) and short-course immunosuppressive prednisolone.

Question 26Companion-animal clinical reasoning and individual assessment

A 4-year-old male neutered Domestic Shorthair cat presents with acute vomiting, lethargy, and anorexia. Abdominal ultrasound demonstrates a target-like 'concentric ring' multilayered mass in the ileocecal region. What gastrointestinal emergency is present?

  1. Gastric adenocarcinoma
  2. Megacolon
  3. Intussusception (Invagination), where a proximal segment of bowel invaginates into the lumen of an immediately adjacent distal bowel segment Correct answer.
  4. Linear foreign body laceration

Explanation

Intussusception (Invagination) occurs when a segment of intestine (the intussusceptum) invaginates (telescopes) into the lumen of an adjacent segment (the intussuscipiens). It is typically triggered by enteritis, foreign bodies, parasites, or lymphoid hyperplasia. Ultrasound reveals a pathognomonic concentric multi-layered ring pattern ('target' or 'bullseye' sign in cross section). Emergency surgical reduction or enterectomy is required to prevent ischemic bowel necrosis.

Question 27Companion-animal clinical reasoning and individual assessment

A 7-year-old Domestic Shorthair male cat presents with acute onset of head tilt to the left, horizontal nystagmus with the fast phase to the right, falling and rolling to the left, and left-sided Horner's syndrome (miosis, ptosis, enophthalmos, and third eyelid protrusion). Conscious proprioception and spinal reflexes are normal in all four limbs. What is the anatomical localization of the lesion?

  1. Central vestibular lesion involving the right cerebellar peduncle
  2. Cervical spinal cord segment C1–C5 lesion
  3. Left-sided Peripheral Vestibular System (involving the left inner ear / vestibular apparatus / vestibulocochlear nerve CN VIII) Correct answer.
  4. Forebrain lesion in the right cerebral hemisphere

Explanation

Peripheral Vestibular Disease is characterized by head tilt towards the side of the lesion, horizontal or rotary nystagmus (fast phase AWAY from the lesion), and vestibular ataxia without proprioceptive or motor deficits in the limbs. Concurrent ipsilateral Horner's syndrome frequently occurs in peripheral disease (such as otitis media/interna or nasopharyngeal polyps) because post-ganglionic sympathetic fibers course directly through the middle ear cavity adjacent to the tympanic bulla.

Question 28Companion-animal clinical reasoning and individual assessment

A 4-year-old female Bernese Mountain Dog presents with acute progressive ataxia, ascending flaccid tetraparesis, loss of spinal reflexes (hyporeflexia/areflexia), loss of muscle tone (hypotonia), and weak phonation (dysphonia) developing 10 days after a racoon/fox encounter and tick attachment. Cranial nerve reflexes and sensorium are alert, and deep pain sensation is intact. What peripheral lower motor neuron disease is diagnosed?

  1. Tetanus causing spastic rigidity
  2. Cervical spinal cord compression (Hansen Type I IVDD)
  3. Acute Canine Polyradiculoneuritis (Coonhound Paralysis / Idiopathic Polyradiculoneuritis), an immune-mediated demyelinating neuropathy affecting ventral nerve roots and peripheral nerves Correct answer.
  4. Myasthenia gravis

Explanation

Acute Canine Polyradiculoneuritis (Coonhound Paralysis) is an acute, immune-mediated, post-infectious demyelinating polyneuropathy analogous to human Guillain-Barré syndrome. Autoantibodies target antigens in the ventral motor roots and peripheral nerves, causing rapid ascending Lower Motor Neuron (LMN) flaccid paralysis (hyporeflexia, hypotonia, paresis) starting in pelvic limbs and progressing to thoracic limbs and dysphonia, with sensory and mentation spared. Supportive nursing care (preventing decubital ulcers, respiratory support) leads to recovery over weeks to months.

Question 29Ruminant metabolism, herd evidence and reproductive health

A high-yielding Swiss dairy cow in the 4th week of lactation presents with sweet, fruity (acetone-like) breath odor, sudden drop in concentrate intake, reduced milk yield, firm dry feces, and licking of stall fixtures (pica). Dipstick urine testing reveals ++++ acetoacetate/ketones. What is the fundamental biochemical mechanism of bovine ketosis (Acetonemia), and what is the standard medical treatment?

  1. Excessive dietary protein intake causing ammonia toxicity; treated with oral vinegar
  2. Primary insulin-dependent Type 1 diabetes; treated with lifelong porcine lente insulin injections
  3. Vitamin D intoxication; treated with oral calcitonin
  4. Negative energy balance where glucose demand for milk lactose synthesis exceeds hepatic gluconeogenesis, causing massive adipose lipolysis, NEFA mobilization, and accumulation of ketone bodies (beta-hydroxybutyrate, acetoacetate); treated with oral propylene glycol, IV 50% dextrose, and glucocorticoids Correct answer.

Explanation

Bovine Ketosis (Acetonemia) occurs in high-producing dairy cows during early lactation when energy demands for milk synthesis exceed dry matter intake (Negative Energy Balance). Intense lipolysis mobilizes non-esterified fatty acids (NEFAs) to the liver. When the capacity of the Krebs cycle (requiring oxaloacetate derived from glucose/propionate) is overwhelmed, hepatic acetyl-CoA is shunted into ketogenesis, producing beta-hydroxybutyrate (BHB), acetoacetate, and acetone. Standard treatment provides glucogenic precursors (oral propylene glycol 300 mL bid) and IV glucose.

Question 30Ruminant metabolism, herd evidence and reproductive health

A group of 6-month-old calves at pasture in the Swiss Prealps develops severe paroxysmal coughing, tachypnea, dyspnea with head-extended posture, and poor growth during late summer. Auscultation reveals diffuse crackles and wheezes over the caudodorsal lung fields. Baermann fecal examination reveals first-stage larvae (L1) with an anterior cuticular button and pointed tail. What parasite is causing Bovine Parasitic Bronchitis (Lungworm Disease / Lungenwurmbefall)?

  1. Fasciola hepatica (Liver fluke)
  2. Ostertagia ostertagi (Brown stomach worm)
  3. Haemonchus contortus (Barber's pole worm)
  4. Dictyocaulus viviparus (Bovine lungworm) Correct answer.

Explanation

Dictyocaulus viviparus is the bovine lungworm. Infective L3 larvae on pasture (spread by the fungus Pilobolus) are ingested, migrate via mesenteric lymph nodes to the lungs, and mature in the mainstem bronchi and bronchioles, causing severe parasitic bronchitis, tracheitis, and verminous pneumonia. Diagnosis is confirmed by identifying L1 larvae in feces using the Baermann sedimentation technique. Treatment with macrocyclic lactones (ivermectin, moxidectin) or benzimidazoles (fenbendazole) is highly effective.

Question 31Ruminant metabolism, herd evidence and reproductive health

A dairy cow in third lactation presents with acute clinical mastitis in the right hind quarter 24 hours after calving. The quarter is swollen, hot, and painful, yielding watery, reddish serous secretion with fibrin flakes. The cow displays severe depression, tachycardia (110 bpm), subnormal rectal temperature (37.5°C), cold extremities, scleral injection, and ruminal atony. What pathogen is primarily responsible for this toxic (endotoxic) mastitis?

  1. Streptococcus agalactiae (obligate contagious pathogen)
  2. Corynebacterium bovis
  3. Staphylococcus aureus chronic microabscesses
  4. Escherichia coli (or other coliforms like Klebsiella pneumoniae) releasing Lipopolysaccharide (LPS / Endotoxin) Correct answer.

Explanation

Acute toxic/endotoxic mastitis in dairy cattle is predominantly caused by environmental Gram-negative coliform bacteria, primarily Escherichia coli and Klebsiella pneumoniae. Rapid bacterial lysis within the mammary gland releases massive amounts of Lipopolysaccharide (LPS / Endotoxin) into the circulation, triggering systemic inflammatory response syndrome (SIRS), profound hypocalcemia, distributive shock, hypothermia, ruminal stasis, and dehydration. Therapy requires aggressive IV fluids, NSAIDs (flunixin meglumine), frequent quarter stripping, and systemic antimicrobials.

Question 32Ruminant metabolism, herd evidence and reproductive health

A flock of 150 Swiss White Alpine sheep at pasture in autumn develops severe acute lameness in over 30% of the flock. Examination of the feet reveals moist foul-smelling interdigital necrotizing dermatitis with separation of the hoof horn from the underlying sensitive laminae starting at the axial margin and progressing across the sole. What is the specific primary pathogen causing Contagious Ovine Footrot (Moderhinke), and what is the national eradication strategy in Switzerland?

  1. Staphylococcus aureus; treated with individual intramammary infusions
  2. Clostridium botulinum; managed with oral glucose drenching
  3. Foot-and-Mouth Disease Virus; treated with herbal balms
  4. Dichelobacter nodosus (specifically virulent strains carrying the aprV2 gene) acting synergistically with Fusobacterium necrophorum; Switzerland implemented a national Moderhinke eradication program using PCR testing, footbaths, and culling of chronic carriers Correct answer.

Explanation

Contagious Ovine Footrot (Moderhinke) is an infectious, highly contagious pododermatitis of small ruminants caused by virulent strains of Dichelobacter nodosus (harboring the aprV2 protease gene), which invade macerated interdigital skin pre-damaged by Fusobacterium necrophorum. In Switzerland, a mandatory national Moderhinke eradication program was launched utilizing flock-level real-time PCR testing (distinguishing virulent aprV2 from benign aprB2 strains), zinc/copper sulfate footbaths, and strict culling of refractory sheep.

Question 33Ruminant metabolism, herd evidence and reproductive health

A pastured group of beef steers in Switzerland shows sudden onset of dark red urine (redwater / hemoglobinuria), high fever (41.0°C), severe hemolytic anemia, icterus, ataxia, and pipe-stem feces during late spring. Blood smear examination stained with Giemsa reveals paired, pear-shaped intraerythrocytic protozoal merozoites within red blood cells. What vector-borne hemoparasite causes Bovine Babesiosis (Redwater Fever / Piroplasmose)?

  1. Theileria annulata
  2. Trypanosoma evansi
  3. Anaplasma marginale
  4. Babesia divergens (transmitted by the tick Ixodes ricinus) Correct answer.

Explanation

Bovine Babesiosis (Redwater / Piroplasmose in Central Europe) is caused by Babesia divergens, an intraerythrocytic protozoan parasite transmitted by the hard tick Ixodes ricinus. Trophozoites replicate inside host erythrocytes, causing acute intravascular hemolysis, marked hemoglobinuria ('redwater'), fever, icterus, and anemia. Diagnosis is confirmed by demonstrating small, paired divergence-angled merozoites on thin blood smear. Treatment with imidocarb dipropionate or diminazene aceturate is curative.

Question 34Ruminant metabolism, herd evidence and reproductive health

A group of 3-week-old calves in a collective rearing pen develops severe watery, yellowish diarrhea, dehydration, and weakness. Fecal flotation using saturated sucrose solution and modified Ziehl-Neelsen acid-fast staining reveals spherical, red-staining oocysts measuring 4 to 5 µm in diameter. What protozoan zoonotic parasite is responsible for neonatal calf cryptosporidiosis?

  1. Eimeria zuernii
  2. Giardia duodenalis
  3. Toxoplasma gondii
  4. Cryptosporidium parvum Correct answer.

Explanation

Cryptosporidium parvum is an intracellular, extracytoplasmic protozoan parasite that infects microvillous enterocytes in the distal small intestine of calves aged 1 to 4 weeks, causing villous blunting, malabsorptive watery diarrhea, and dehydration. Diagnosis is confirmed by identifying 4–5 µm acid-fast oocysts on modified Ziehl-Neelsen fecal smears or point-of-care rapid antigen tests. C. parvum is a major zoonotic pathogen causing severe gastroenteritis in humans. Halofuginone lactate or paromomycin provides therapeutic/prophylactic suppression.

Question 35Ruminant metabolism, herd evidence and reproductive health

A sheep flock in the Swiss Prealps grazing in wetlands during autumn experiences acute mortality in multiple ewes. Post-mortem examination reveals acute hemorrhagic tracts through the hepatic parenchyma, subcapsular hematomas, blood-stained peritoneal effusion, and immature flukes in the liver tissue. What parasitic liver fluke and intermediate host snail are responsible for Fasciolosis (Großer Leberegelbefall)?

  1. Dicrocoelium dendriticum, utilizing land snails and Formica ants
  2. Paramphistomum cervi, utilizing planorbid water snails
  3. Taenia hydatigena, utilizing dogs as definitive hosts
  4. Fasciola hepatica, utilizing the mud snail Galba truncatula (Lymnaea truncatula) as intermediate host Correct answer.

Explanation

Fasciola hepatica (the Common Liver Fluke) is a major parasite of ruminants across wet pastures in Switzerland. Miracidia infect the mud snail Galba truncatula (Lymnaea truncatula), where they multiply into cercariae and encyst as metacercariae on grass. Following ingestion, juvenile flukes excyst in the duodenum, penetrate the intestinal wall, and burrow through hepatic parenchyma for 6–8 weeks, causing acute traumatic hepatitis, blood loss, and death (Acute Fasciolosis) before maturing in bile ducts (Chronic Fasciolosis). Triclabendazole is the drug of choice for killing both immature and adult flukes.

Question 36Ruminant metabolism, herd evidence and reproductive health

A dairy farm in Switzerland experiences a summer outbreak of acute hemorrhagic enteritis, fever, and drop in milk yield in adult cattle, while several 2-month-old calves present with acute fibrinous pneumonia, polyarthritis, and septicemia. Fecal and tissue culture confirms Salmonella enterica subspecies enterica serovar Dublin. What is the characteristic epidemiological feature of Salmonella Dublin in cattle herds?

  1. Salmonella Dublin is non-pathogenic in adult cattle and causes disease only in horses
  2. Salmonella Dublin is an obligate parasite of intestinal cestodes
  3. Salmonella Dublin cannot survive in farm environments for more than 2 minutes
  4. Salmonella Dublin is host-adapted to cattle, capable of establishing lifelong latent carrier states in mesenteric lymph nodes and gallbladders of recovered animals, shedding bacteria during periods of parturition or transport stress Correct answer.

Explanation

Salmonella enterica serovar Dublin is a host-adapted, highly invasive serovar of cattle. It causes severe septicemic enteritis and abortion in adult cows, and acute bacteremia, pneumonia, and osteomyelitis in calves. A crucial epidemiological hallmark of S. Dublin is its ability to establish permanent latent carrier status in the liver, gallbladder, and mesenteric lymph nodes of recovered animals. These asymptomatic carrier cows intermittently shed high bacterial loads during immunosuppressive stress (calving, transport), driving endemic herd persistence.

Question 37Equine clinical assessment, colic and locomotor problems

A 5-year-old pony with severe grain overload develops acute, bilateral forelimb laminitis (Hufrehe). The pony stands with forelimbs extended forward, shifting weight onto its hindquarters, and displays bounding digital pulses and warm hooves. Lateral radiographs of the front feet reveal 8 degrees of palmar rotation of the third phalanx (P3 / pedal bone) with thinning of the sole depth. What anatomical structure is primarily damaged during laminitis?

  1. Interlocking dermal and epidermal laminae (suspensory apparatus of the distal phalanx / Hufbeinträger), leading to biomechanical separation under the tensile pull of the deep digital flexor tendon (DDFT) Correct answer.
  2. Collateral cartilages of the foot (cartilago ungularis)
  3. Proximal sesamoidean ligaments
  4. Common digital extensor tendon

Explanation

Equine laminitis (Hufrehe) is a debilitating disease characterized by inflammation, enzymatic degradation, and ischemic necrosis of the interdigitating epidermal and dermal laminae (the Hufbeinträger / laminar suspensory apparatus) that anchor the third phalanx (P3) to the inner hoof wall. Failure of this laminar attachment allows the downward pulling force of the deep digital flexor tendon (DDFT) and body weight to rotate or sink the distal phalanx (P3) toward the sole.

Question 38Equine clinical assessment, colic and locomotor problems

A 10-year-old Warmblood gelding in an equestrian facility in the Swiss canton of Bern presents with acute ataxia, symmetric proprioceptive deficits in all four limbs (worse in hindlimbs), pelvic limb weakness, toe dragging, and circumduction when turned in tight circles. Cervical radiographs reveal vertebral canal narrowing and static/dynamic malformation at C5–C6 and C6–C7. What is the clinical diagnosis?

  1. Cervical Vertebral Stenotic Myelopathy (CVSM / Wobbler Syndrome) Correct answer.
  2. Equine Protozoal Myeloencephalitis (EPM)
  3. Tetanus caused by deep puncture wound
  4. Polyneuritis equi (Cauda equina syndrome)

Explanation

Cervical Vertebral Stenotic Myelopathy (CVSM / Wobbler Syndrome) is a developmental/degenerative orthopedic disease in horses characterized by narrowing (stenosis) of the cervical vertebral canal leading to dynamic (flexion-induced) or static spinal cord compression. Compressive damage to ascending and descending spinocerebellar and motor tracts produces characteristic symmetric, uncoordinated tetraparesis and proprioceptive deficits ('wobbly' gait, toe scuffing, circumduction). Definitive diagnosis utilizes standing cervical radiographs, intravertebral sagittal diameter ratios (<50%), and myelography.

Question 39Equine clinical assessment, colic and locomotor problems

A 4-year-old Warmblood gelding presents with acute, high fever (40.2°C), severe depression, petechiae on mucous membranes, anorexia, marked ventral edema of the sheath and distal limbs, and severe icteric sclera. Complete blood count shows severe thrombocytopenia (35,000/µL), anemia, and leukopenia. Direct blood smear reveals basophilic, morulae-like intracytoplasmic inclusion bodies inside neutrophils. What is the diagnosis and vector-borne organism?

  1. Equine Granulocytic Anaplasmosis (formerly Ehrlichia equi), caused by Anaplasma phagocytophilum and transmitted by Ixodes ricinus ticks Correct answer.
  2. Equine Infectious Anemia (EIA / Lentivirus)
  3. Piroplasmosis caused by Babesia caballi
  4. Lyme disease caused by Borrelia burgdorferi

Explanation

Equine Granulocytic Anaplasmosis (EGA, formerly Ehrlichia equi) is caused by the obligate intracellular bacterium Anaplasma phagocytophilum, transmitted across Europe by the sheep tick Ixodes ricinus. The organism infects circulating neutrophils. Clinical hallmarks include high fever, lethargy, distal limb edema, petechiae, ataxia, and profound thrombocytopenia. Diagnosis is confirmed by identifying characteristic intracytoplasmic morulae clusters in neutrophils on blood smear or via PCR. Intravenous oxytetracycline produces rapid clinical recovery.

Question 40Equine clinical assessment, colic and locomotor problems

An 8-year-old Icelandic horse presents in summer with intense pruritus, excoriations, alopecia, and skin lichenification localized along the mane, dorsal midline, and tail base ('sweet itch' / Sommerekzem). What is the underlying immunological hypersensitivity and insect vector responsible for Equine Insect Bite Hypersensitivity (IBH)?

  1. Type I (IgE-mediated) and Type IV hypersensitivity reaction to salivary antigens of biting midges (Culicoides spp.) Correct answer.
  2. Direct mechanical irritation caused by houseflies (Musca domestica)
  3. Sarcoptic mange mite infestation (Sarcoptes scabiei var. equi)
  4. Autoimmune pemphigus foliaceus targeting desmoglein-1

Explanation

Equine Insect Bite Hypersensitivity (IBH / Summer Eczema / Sommerekzem) is the most common allergic skin disease of horses worldwide, particularly prevalent in Icelandic horses imported to mainland Europe. It is an IgE-mediated Type I and cell-mediated Type IV allergic reaction to salivary allergen proteins injected during the bites of biting midges (Culicoides spp., e.g., C. obsoletus, C. pulicaris). Management relies on fly sheets/rugs, housing horses during peak twilight midge feeding hours, topical insect repellents (permethrin), and corticosteroids.

Question 41Equine clinical assessment, colic and locomotor problems

A 7-year-old Quarter Horse gelding is presented for routine dental examination. Oral speculum examination reveals marked sharp enamel points on the buccal aspect of the maxillary cheek teeth and lingual aspect of the mandibular cheek teeth, causing painful buccal ulcerations. What anatomical feature of the equine skull and anisognathic jaw relationship creates this predictable pattern of dental wear?

  1. The equine maxilla is wider than the mandible (anisognathism), and the normal side-to-side (lateral) masticatory grinding motion causes sharp enamel points to form on the outer (buccal) edge of upper cheek teeth and inner (lingual) edge of lower cheek teeth Correct answer.
  2. Horses have brachydont teeth that do not erupt continuously
  3. Enamel points form only when horses are fed high-grain commercial feeds
  4. Upper cheek teeth are aligned entirely medial to lower teeth

Explanation

Equine dentition is hypsodont (continuously erupting ~2–3 mm/year). The equine skull is naturally anisognathic: the maxillary arcade is approximately 30% wider than the mandibular arcade. During lateral figure-eight chewing cycles, incomplete occlusion of the outermost upper edges and innermost lower edges results in the formation of sharp enamel points on the buccal aspect of maxillary cheek teeth and lingual aspect of mandibular cheek teeth. Routine dental rasping (floating) removes these points to prevent oral ulcerations.

Question 42Equine clinical assessment, colic and locomotor problems

A 10-year-old Warmblood mare presents for breeding soundness examination. Transrectal ultrasonography reveals a large (12 cm), unilateral, multicystic 'honeycomb-like' ovary with destruction of normal follicular architecture, while the contralateral ovary is small, inactive, and atrophic. The mare has displayed persistent stallion-like aggressive behavior, neck crest development, and continuous anestrus. What ovarian neoplasm is diagnosed?

  1. Granulosa-Theca Cell Tumor (GCT / Granulosazelltumor); diagnosis confirmed by elevated serum Anti-Müllerian Hormone (AMH), inhibin, or testosterone Correct answer.
  2. Ovarian Teratoma
  3. Dysgerminoma
  4. Ovarian papillary adenocarcinoma

Explanation

Granulosa-Theca Cell Tumor (GCT) is the most common ovarian neoplasm in mares. It is benign and secretes excessive hormones: 1) Inhibin (which feeds back to suppress pituitary FSH, causing atrophy and inactivity of the contralateral ovary); 2) Testosterone (causing masculine stallion-like behavior and cresty neck); and 3) Anti-Müllerian Hormone (AMH). Serum AMH assay has a diagnostic sensitivity >95% for equine GCT. Unilateral laparoscopic ovariectomy is curative, and the atrophic contralateral ovary typically resumes normal cyclicity within 1–2 years.

Question 43Equine clinical assessment, colic and locomotor problems

A 5-year-old Arabian mare presents with acute, progressive muscle stiffness, third eyelid prolapse when startled, erect ears, flared nostrils, 'sawhorse' rigid stance, trismus ('lockjaw'), and hypersensitivity to light and noise. What neurotoxin-producing bacterium causes Tetanus (Wundstarrkrampf) following anaerobic wound infection?

  1. Clostridium tetani producing tetanospasmin, which blocks the release of inhibitory neurotransmitters (GABA and glycine) from Renshaw interneurons in the spinal cord Correct answer.
  2. Clostridium botulinum producing botulinum neurotoxin
  3. Listeria monocytogenes causing microabscesses in the brainstem
  4. Bacillus anthracis producing lethal toxin

Explanation

Tetanus (Wundstarrkrampf) is caused by Clostridium tetani, a spore-forming anaerobic soil bacterium that infects puncture wounds. Tetanospasmin neurotoxin ascends retrogradely along motor axons to the spinal cord, where it cleaves synaptobrevin and irreversibly prevents the exocytosis of inhibitory neurotransmitters (GABA and glycine) from Renshaw inhibitory interneurons. This leads to unregulated, continuous motor neuron firing, producing spastic tetanic paralysis, third eyelid prolapse, sawhorse posture, and respiratory failure.

Question 44Companion-animal clinical reasoning and individual assessment

In the stated classical teaching sequence of inspection, palpation, percussion and auscultation, which listed order reproduces that convention rather than a mandatory physiological order for every veterinary examination?

  1. Auscultation, Palpation, Blood biochemistry, Endoscopy
  2. Percussion, Surgery, Inspection, Palpation
  3. Olfaction, Biopsy, Inspection, Auscultation
  4. Inspection (Visual exam), Palpation, Percussion, Auscultation (视诊、触诊、叩诊、听诊) Correct answer.

Explanation

The four fundamental non-invasive physical examination techniques in veterinary diagnostics are Inspection (视诊 / visual evaluation from a distance and up close), Palpation (触诊 / manual touch for temperature, pain, consistency), Percussion (叩诊 / tapping to elicit resonant/dull sounds), and Auscultation (听诊 / listening to heart, lung, and gastrointestinal sounds).

Question 45Companion-animal clinical reasoning and individual assessment

In feline and canine clinical diagnostics, what abnormal mucosal coloration is characteristically caused by elevated levels of circulating total bilirubin (> 2.0 mg/dL or > 34 micromol/L) due to pre-hepatic hemolysis, hepatic disease, or post-hepatic biliary obstruction?

  1. Cyanosis (发绀 / 紫绀)
  2. Jaundice / Icterus (黄疸) Correct answer.
  3. Pallor (苍白)
  4. Cherry-red hyperemia (樱桃红 / 充血)

Explanation

Jaundice (黄疸 / Icterus) is the yellow discoloration of mucous membranes, sclera, and non-pigmented skin caused by hyperbilirubinemia, resulting from hemolytic crisis (pre-hepatic), hepatocellular failure (hepatic), or bile duct obstruction (post-hepatic).

Question 46Companion-animal clinical reasoning and individual assessment

A 4-month-old unvaccinated puppy presents with acute onset of high fever (40°C), intractable vomiting, severe foul-smelling bloody diarrhea ('tomato soup' appearance), profound dehydration, and severe leukopenia (WBC 1.2 x 10^9/L). Rapid fecal ELISA is positive. What is the diagnosis and primary pathophysiology?

  1. Infectious Canine Hepatitis; primary endothelial necrosis in hepatic sinusoids
  2. Canine Coronavirus enteritis; superficial villus tip sloughing only without leukopenia
  3. Canine Parvovirus (CPV-2 / 犬细小病毒病); viral destruction of intestinal crypt epithelial cells and lymphoid bone marrow progenitor cells (病毒破坏肠隐窝上皮与骨髓造血干细胞) Correct answer.
  4. Salmonella enterica infection; chronic localized typhlitis without bone marrow involvement

Explanation

Canine Parvovirus Type 2 (CPV-2) targets rapidly dividing cells: the germinal cells of intestinal crypts (causing severe villous blunting, mucosal collapse, and foul-smelling hemorrhagic diarrhea) and hematopoietic progenitor cells in bone marrow and lymphoid tissues (causing severe panleukopenia).

Question 47Companion-animal clinical reasoning and individual assessment

A 6-month-old stray dog is rescued with a history of biphasic fever (双相热), purulent oculonasal discharge, severe coughing, hyperkeratosis of the footpads and nasal planum ('hard pad disease' / 硬足垫病), followed 3 weeks later by localized chorea (myoclonus muscle twitching) and seizures. What is the pathogen?

  1. Rabies Virus (狂犬病毒 - Lyssavirus)
  2. Canine Adenovirus Type 2 (犬腺病毒2型)
  3. Bordetella bronchiseptica (支气管败血鲍特氏菌)
  4. Canine Distemper Virus (CDV / 犬瘟热病毒 - Morbillivirus) Correct answer.

Explanation

Canine Distemper Virus (CDV, genus Morbillivirus) produces multi-systemic pathology: respiratory catarrh, gastrointestinal enteritis, hyperkeratosis of digital footpads and nose planum (hard pad disease), and secondary central nervous system demyelinating encephalitis causing characteristic rhythmic myoclonus (chorea) and seizures.

Question 48Companion-animal clinical reasoning and individual assessment

A 5-month-old kitten presents with sudden high fever, profound lethargy, persistent vomiting, severe dehydration, and sitting with its head hung over the water bowl without drinking. Complete blood count reveals WBC count of 0.4 x 10^9/L (extreme panleukopenia). What is the causative virus?

  1. Feline Panleukopenia Virus (FPV / 猫泛白细胞减少症病毒 / 猫瘟病毒 - Parvovirus) Correct answer.
  2. Feline Herpesvirus-1 (FHV-1 / 猫疱疹病毒1型)
  3. Feline Calicivirus (FCV / 猫杯状病毒)
  4. Feline Leukemia Virus (FeLV / 猫白血病病毒)

Explanation

Feline Panleukopenia Virus (FPV / feline distemper) is a feline protoparvovirus that destroys active mitotic cells in the bone marrow (causing profound panleukopenia affecting all leukocyte cell lines) and the intestinal crypt epithelium (causing intractable vomiting and severe hemorrhagic enteritis).

Question 49Companion-animal clinical reasoning and individual assessment

A 1-year-old cat presents with progressive abdominal distension, fluctuating fever unresponsive to antibiotics, and weight loss. Abdominocentesis yields viscous, straw-yellow, sticky fluid with high total protein (> 35 g/L), low albumin/globulin ratio (A:G < 0.4), and a positive Rivalta test (李凡他试验阳性). What disease does this effusion profile strongly indicate?

  1. Bacterial septic peritonitis caused by gastrointestinal perforation
  2. Congestive right-sided heart failure pure transudate
  3. Effusive 'Wet' Feline Infectious Peritonitis (渗出型猫传染性腹膜炎 / 湿性传腹 - FIP / Feline Coronavirus mutation) Correct answer.
  4. Hepatic cirrhosis pure hypoalbuminemic transudate

Explanation

Effusive (Wet) FIP is caused by mutated Feline Coronavirus (FCoV) replicating in monocytes and inducing systemic pyogranulomatous vasculitis. The resulting peritoneal effusion is characteristically straw-yellow, viscous, non-septic, high in protein (> 3.5 g/dL) and globulins (A:G < 0.4–0.6), and strongly positive on the Rivalta test.

Question 50Ruminant metabolism, herd evidence and reproductive health

In the ruminant stomach anatomy, which compartment is lined with a glandular mucous membrane that secretes gastric juice, pepsinogen, and hydrochloric acid, functionally equivalent to the monogastric stomach?

  1. Rumen (瘤胃)
  2. Reticulum (网胃)
  3. Omasum (瓣胃)
  4. Abomasum (皱胃) Correct answer.

Explanation

The Abomasum (皱胃) is the true glandular stomach of ruminants (cattle, sheep, goats). Unlike the forestomachs (rumen, reticulum, omasum), which have stratified squamous aglandular epithelium for mechanical mixing and microbial fermentation, the abomasum possesses gastric glands that secrete hydrochloric acid, pepsinogen, and rennin for enzymatic digestion.