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FVH Wiederkäuer practice questions

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Question 1Ruminant metabolism, herd evidence and reproductive health

A 4-year-old Swiss Fleckvieh cow 14 days postpartum presents with anorexia, selective concentrate refusal, decreased rumen motility, and a high-pitched resonant 'ping' on simultaneous auscultation and percussion over the left 9th to 12th intercostal spaces. What characteristic serum biochemical abnormalities are typically expected in this uncomplicated Left Displaced Abomasum (LDA) case?

  1. Hypochloremic, hypokalemic metabolic alkalosis with paradoxical aciduria Correct answer.
  2. Hyperchloremic, hyperkalemic metabolic acidosis with alkaline urine
  3. Normochloremic metabolic acidosis with severe lactic acidemia
  4. Hypernatremic, hypercalcemic respiratory alkalosis

Explanation

Abomasal hypomotility and displacement lead to continued secretion of hydrochloric acid into the abomasal lumen and subsequent sequestration or reflux into the rumen. Sequestration of chloride and hydrogen ions results in hypochloremia and systemic metabolic alkalosis. As the kidneys attempt to conserve sodium and volume in response to dehydration, aldosterone stimulates potassium and hydrogen ion excretion in the renal tubules, producing hypokalemia and paradoxical aciduria.

Question 2Ruminant metabolism, herd evidence and reproductive health

A dairy cow presents with acute severe abdominal pain, tachycardia (115 bpm), cool extremities, dehydration (>8%), and a large resonant percussion area in the right cranial abdomen extending to the 8th rib. Blood analysis reveals severe hypochloremia (68 mmol/L) and an elevated plasma L-lactate concentration of 6.5 mmol/L. What is the primary diagnosis and prognostic interpretation?

  1. Simple right abomasal dilation; excellent prognosis with conservative medical therapy and oral fluids
  2. Cecal volvulus; fair prognosis requiring right paralumbar typhlotomy
  3. Acute vagal indigestion type I; guarded prognosis requiring transfaunation
  4. Right Abomasal Volvulus (RAV) with ischemic wall necrosis; poor to guarded surgical prognosis due to severe hyperlactatemia Correct answer.

Explanation

Right abomasal volvulus (RAV / abomasal torsion) causes vascular strangulation of the abomasal blood supply (omental and gastric vessels), leading to rapid ischemic necrosis, severe fluid sequestration, endotoxemia, and shock. A plasma L-lactate concentration exceeding 4.0 to 5.0 mmol/L in cattle with RAV is a validated objective biomarker indicating extensive abomasal wall ischemia and significantly reduced postoperative survival.

Question 3Ruminant metabolism, herd evidence and reproductive health

What is the primary physiological mechanism by which a negative Dietary Cation-Anion Difference (DCAD) diet fed to dry cows in the final 3 weeks prepartum prevents clinical and subclinical hypocalcemia at calving?

  1. It stimulates insulin secretion and increases renal calcium reabsorption
  2. It induces a mild systemic metabolic acidosis that enhances tissue sensitivity to parathyroid hormone (PTH) and upregulates 1,25-dihydroxyvitamin D3 synthesis Correct answer.
  3. It binds dietary phosphorus in the rumen, directly forcing active intestinal calcium transport
  4. It elevates blood pH, promoting calcitonin release and bone mineral deposition

Explanation

Negative DCAD diets (supplemented with anionic salts such as magnesium sulfate, calcium chloride, or ammonium chloride) induce a mild, compensated metabolic acidosis (target urine pH 6.0–6.5 in Holsteins, 5.8–6.2 in Jerseys). This acidotic state alters the conformation of the PTH receptor on osteoclasts and renal tubule cells, greatly enhancing tissue responsiveness to parathyroid hormone and optimizing osteoclastic bone calcium resorption and active renal 1,25-(OH)2-D3 activation.

Question 4Ruminant reproductive physiology, calving and udder health

A dairy herd in the Swiss plateau experiences an abortion storm affecting 15% of cows in late gestation. Necropsy of aborted fetuses reveals severe, thickened, leathery intercotyledonary placentitis with grey-white exudate. Histopathology and PCR on cotyledons demonstrate massive intracellular infection with Coxiella burnetii. What is the major zoonotic and public health risk associated with this pathogen?

  1. It causes cutaneous larva migrans in veterinarians
  2. It only infects non-human primates through mosquito bites
  3. It is an obligate parasite of the equine stomach with no human pathogenicity
  4. It is the causative agent of Q-fever in humans, shedding heavily in birth fluids, placenta, milk, and feces, and is highly infectious via aerosol inhalation Correct answer.

Explanation

Coxiella burnetii is the zoonotic bacterium causing Q-fever (Query fever) in humans and epizootic abortions in ruminants. The placenta and amniotic fluids of infected ruminants contain massive bacterial loads (up to 10^9 organisms per gram). Humans become infected primarily via inhalation of desiccated aerosolized dust from contaminated birth materials. In humans, acute Q-fever presents as a severe flu-like illness or atypical pneumonia, while chronic Q-fever causes fatal endocarditis.

Question 5Ruminant reproductive physiology, calving and udder health

Bovine Neonatal Pancytopenia (BNP / 'bleeding calf syndrome') was an immune-mediated disorder of newborn calves characterized by profound bone marrow trilineage hypoplasia, severe thrombocytopenia, and generalized cutaneous and mucosal hemorrhage. What was the established immunological pathogenesis of BNP?

  1. Direct viral destruction of megakaryocytes by a mutant pestivirus strain
  2. Inborn autosomal recessive mutation in the thrombopoietin receptor gene
  3. Ingestion of maternal colostrum containing alloreactive anti-MHC class I antibodies induced in dams hyperimmunized with a specific adjuvanted BVDV vaccine (PregSure BVD) Correct answer.
  4. Acute mycotoxicosis caused by T-2 toxin in whole milk replacer

Explanation

BNP was caused by maternal alloreactive antibodies transferred via colostrum to newborn calves. Dams vaccinated repeatedly with a specific highly adjuvanted BVD vaccine (PregSure BVD) produced high-titer alloantibodies against bovine MHC Class I antigens derived from the bovine kidney cell line used to culture the vaccine virus. Ingested colostral alloantibodies bound to the calf's hematopoietic progenitor cells, causing destruction of bone marrow stem cells.

Question 6Ruminant reproductive physiology, calving and udder health

Which listed tissue and microbial factors can contribute to difficult bacteriological cure of Staphylococcus aureus mastitis, without assigning one universal lactational cure percentage?

  1. Staphylococcus aureus invades deep parenchymal udder tissue, produces microabscesses, fibrous scar tissue capsules, intracellular persistence inside macrophages, and bacterial biofilms that prevent therapeutic drug penetration Correct answer.
  2. Staphylococcus aureus only replicates in arterial endothelium and never contacts milk
  3. Staphylococcus aureus is an obligate anaerobe that is destroyed by oxygen in milk
  4. Intramammary penicillins are inactivated by lactose in high-producing cows

Explanation

Tissue invasion, protected foci and relevant persistence mechanisms can contribute to difficult elimination of an intramammary Staphylococcus aureus infection. Actual response varies with isolate, chronicity, the cow and treatment conditions. In-vitro susceptibility alone does not guarantee an identical clinical cure, and the answer does not prescribe one antibiotic programme.

Question 7Ruminant limb anatomy, claw lesions and locomotor assessment

According to the international M-stage classification for Digital Dermatitis (Mortellaro disease caused by Treponema phagedenis, T. medium, T. pedis), what lesion characteristics define an active, highly painful M2-stage ulcer, and what is the standard targeted individual treatment?

  1. Hyperkeratotic chronic proliferative wart (M4) treated with systemic dexamethasone
  2. Completely healed epithelial scar (M0) requiring no intervention
  3. Ulcerative, bright red, granulomatous, painful lesion > 2 cm in diameter (strawberry-like appearance) located at the interdigital cleft/heel skin; treated with thorough cleaning, drying, and topical oxytetracycline spray/powder under a non-constrictive temporary bandage Correct answer.
  4. Subclinical microscopic lesion only detectable by histopathology

Explanation

In the M-stage classification (Döpfer and Read): M0 = normal skin; M1 = early subclinical lesion (<2 cm); M2 = acute, active, painful ulcerative/granulomatous lesion >= 2 cm diameter with red strawberry-like appearance, responsible for acute lameness; M3 = healing stage under scab; M4 = chronic dyskeratotic/proliferative stage; M4.1 = chronic lesion with active M2 recurrence. Individual M2 treatment requires cleaning, drying, and topical oxytetracycline under a light bandage removed within 2 to 3 days.

Question 8Ruminant limb anatomy, claw lesions and locomotor assessment

A high-yielding dairy cow presents with Grade 3/5 lameness in the left hindlimb. Examination of the lateral claw reveals a circumscribed full-thickness defect of the horn with granulation tissue protruding at the sole-bulb junction (Zone 4 / Rusterholz area). What is the primary biomechanical cause and essential therapeutic intervention?

  1. Sinking and backward rotation of the third phalanx (P3) causing flexor tuberosity compression and ischemia of the corium; treatment requires debriding all loose, underrun horn around the ulcer and applying an orthotic wooden/polyurethane block to the healthy partner (medial) claw to relieve weight-bearing Correct answer.
  2. Direct external penetrating nail injury; treatment requires systemic high-dose corticosteroids
  3. Infection with Clostridium tetani; treatment requires hoof amputation
  4. Congenital malformation of the deep digital flexor tendon; treatment requires tenotomy

Explanation

A Sole Ulcer (Pododermatitis circumscripta / Rusterholz ulcer) occurs in Zone 4 due to excessive focal pressure from the flexor process/tuberculum of the distal phalanx (P3) against the vascular corium. This is exacerbated by subclinical laminitis, degradation of the suspensory digital cushion, and hard concrete flooring. Treatment mandates careful paring away of all detached horn margins around the lesion (no loose edges) and applying an orthotic block to the unaffected partner claw to completely offload the diseased claw.

Question 9Ruminant limb anatomy, claw lesions and locomotor assessment

An adult dairy cow develops peracute severe lameness (Grade 4/5), high pyrexia (40.1°C), symmetrical swelling of the entire coronary band and pastern region with spreading of the claw digits, and a foul-smelling necrotic fissure in the interdigital cleft. What is the diagnosis and appropriate evidence-based therapy?

  1. Sole ulcer; local antiseptic spray only
  2. Interdigital Phlegmon (Foul in the foot / Panaritium) caused by Fusobacterium necrophorum and Porphyromonas levii; treatment requires prompt systemic antimicrobial therapy (e.g., ampicillin, oxytetracycline, or ceftiofur) and systemic NSAIDs Correct answer.
  3. Septic arthritis of the fetlock joint; immediate digit amputation
  4. Bovine spastic paresis (Elso heel); bilateral tibial neurectomy

Explanation

Interdigital Phlegmon (Panaritium / Foul in the foot) is an acute necrotizing infection of the subcutaneous interdigital tissues triggered by skin trauma and synergistic infection with Fusobacterium necrophorum, Porphyromonas levii, and Trueperella pyogenes. Hallmark signs include symmetrical cellulitis above the coronary band spreading the claws apart, severe pain, foul odor, and fever. Because it is a deep cellulitis, prompt systemic antimicrobial and NSAID therapy is mandatory and highly effective.

Question 10Small-ruminant and camelid species distinctions

A group of 6-week-old calves housed in a deep-litter straw pen develops dark, watery diarrhea with flecks of fresh blood, tenesmus, tail soiling, and poor growth. Two calves exhibit neurological signs (hyperexcitability, tremors, opisthotonos - 'nervous coccidiosis'). What is the causative agent and standard targeted metaphylactic/therapeutic drug?

  1. Toxoplasma gondii; treated with penicillin G
  2. Giardia duodenalis; treated with albendazole
  3. Eimeria bovis and Eimeria zuernii; treated with toltrazuril or diclazuril Correct answer.
  4. Haemonchus contortus; treated with levamisole

Explanation

Bovine coccidiosis is caused by Eimeria bovis and Eimeria zuernii. Merogony and gametogony in the endothelial cells of the ileum, cecum, and colon cause extensive mucosal sloughing, leading to hemorrhagic typhlocolitis, tenesmus, and dehydration. Nervous coccidiosis is a severe complication associated with E. zuernii infection, likely mediated by a heat-labile neurotoxin or electrolyte imbalance. Toltrazuril or diclazuril administered orally targets all intracellular schizogony stages.

Question 11Small-ruminant and camelid species distinctions

Which listed molecular target comparison is used in relevant real-time PCR methods to distinguish virulence-associated Dichelobacter nodosus alleles, without prescribing the entire current Swiss flock-control procedure?

  1. Serum antibody ELISA against Foot-and-Mouth Disease virus
  2. Real-time PCR performed on interdigital swabs targeting the AprV2 gene (virulent Dichelobacter nodosus) versus the AprB2 gene (benign D. nodosus); only flocks positive for AprV2 are classified as infected and subject to statutory sanitation/quarantine Correct answer.
  3. Fecal culture of Fusobacterium necrophorum on blood agar plates
  4. Skin biopsy of the coronary band for fluorescent antibody testing

Explanation

Relevant real-time PCR methods discriminate the aprV2 and aprB2 protease-gene alleles associated with virulent and benign Dichelobacter nodosus patterns. Interpret the validated assay, sampling and clinical context. A target result is part of the actual current Swiss programme, not by itself a complete statement of flock status, treatment or movement requirements.

Question 12Small-ruminant and camelid species distinctions

A flock of grazing sheep on pasture in late summer experiences sudden deaths, severe lethargy, pale ocular mucous membranes, and submandibular edema ('bottle jaw') without diarrhea. What is the primary nematode parasite involved, and what validated on-farm clinical scoring system is used for targeted selective anthelmintic treatment?

  1. Nematodirus battus; scored via McMaster fecal flotation
  2. Dictyocaulus filaria; scored via Baermann larval migration
  3. Haemonchus contortus (Barber's pole worm); scored using the FAMACHA eye conjunctival color chart (Scores 1 to 5) Correct answer.
  4. Trichuris ovis; scored via skin elasticity testing

Explanation

Haemonchus contortus (the Barber's pole worm) is a blood-feeding abomasal nematode of sheep and goats capable of consuming up to 0.05 mL of blood per worm per day. Heavy infections produce severe regenerative anemia, hypoproteinemia, submandibular edema (bottle jaw), and sudden death without diarrhea. The FAMACHA system evaluates the color of the ocular conjunctiva against a 5-point standardized scale (1 = red/non-anemic to 5 = white/severely anemic) to identify only anemic animals requiring anthelmintics.

Question 13Veterinary pathology, specimens and interpretation

When evaluating a dairy cow with suspected traumatic reticuloperitonitis (TRP / hardware disease) using transabdominal ultrasonography from the ventral 6th to 8th intercostal spaces, which diagnostic findings are pathognomonic for TRP?

  1. Hypercontractile biphasic reticular motility exceeding 5 contractions per 2 minutes with anechoic peritoneal fluid
  2. Complete visualization of the splenic vein without any peritoneal effusion
  3. Reduced or absent reticular biphasic contractions, reticular wall thickening, and echogenic fibrinous deposits with encapsulated hypoechoic fluid pockets Correct answer.
  4. Presence of microvesicular gas artifacts in the abomasal fundus with regular reticular gliding motion

Explanation

Normal reticulum exhibits a smooth half-moon contour with regular biphasic contractions (approx. 1 contraction per minute). In traumatic reticuloperitonitis, ultrasonography reveals localized peritonitis characterized by loss of reticular motility, thickening of the reticular serosa (>5 mm), echogenic fibrin strands, inflammatory adhesions to the diaphragm/abdominal wall, and hypoechoic to heterogeneous inflammatory abscesses/exudate.

Question 14Veterinary pathology, specimens and interpretation

What is the fundamental molecular difference between classical Bovine Spongiform Encephalopathy (c-BSE) and atypical BSE (H-type and L-type BSE)?

  1. Classical BSE is caused by an RNA virus, while atypical BSE is caused by a DNA retrovirus
  2. Classical BSE only infects sheep, while atypical BSE only infects red deer
  3. Classical BSE was epidemic and acquired through ingestion of meat-and-bone meal contaminated with the BSE prion, whereas atypical BSE (H- and L-type) arises sporadically and spontaneously in aged cattle and displays distinct molecular Western blot migration profiles Correct answer.
  4. Classical BSE is non-pathogenic to humans, whereas atypical BSE causes variant Creutzfeldt-Jakob disease

Explanation

Classical BSE has the established feedborne epidemic association, while atypical forms have different molecular profiles and are recognized as very rare sporadic forms found in older cattle. Current WOAH language treats spontaneous occurrence as the accepted explanatory context rather than proof of the precise origin of every individual case. Neither type is diagnosed from age alone.

Question 15Veterinary pathology, specimens and interpretation

A calf rearing facility experiences a severe outbreak of Cryptosporidium parvum enteritis in 10-day-old calves. Why are common quaternary ammonium, chlorine, and alcohol-based disinfectants ineffective against Cryptosporidium parvum oocysts in the environment, and what specific chemical disinfectants are required?

  1. Oocysts have no outer membrane and are destroyed by plain tap water
  2. Oocysts only survive inside adult cow erythrocytes and never enter the barn environment
  3. Oocysts are susceptible only to ultraviolet sunlight indoors
  4. C. parvum oocysts possess a thick, rigid, four-layered oocyst wall highly impermeable to standard chemical agents; effective disinfection requires specialized lipid-permeable cresols/phenol derivatives (e.g., amine/cresol-based products), high heat (steam cleaning > 65°C for >10 minutes), or complete desiccating drying Correct answer.

Explanation

Cryptosporidium oocysts can resist some routinely used disinfectant arrangements, making product suitability, cleaning, actual contact conditions and the complete control plan important. A disinfectant category name alone does not prove effective inactivation. Animal care, environmental exposure and zoonotic protection require an appropriate qualified programme rather than a universal chemical or heat recipe.

Question 16Veterinary 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 17Veterinary epidemiology, zoonoses and food-chain protection

Echinococcus granulosus (细粒棘球绦虫) is a severe zoonotic parasite. What is the typical life cycle relationship between definitive and intermediate hosts in pastoral endemic regions?

  1. Sheep harbor adult tapeworms; earthworms harbor larval stages
  2. Cats harbor adult tapeworms; mice harbor hydatid cysts
  3. Pigs harbor adult tapeworms; dogs ingest eggs to develop muscle cysticerci
  4. Dogs/canids harbor adult tapeworms in their small intestines; sheep/ruminants/humans harbor hydatid cysts in liver/lungs (犬为终末宿主排节片，牛羊/人为中间宿主形成包虫囊) Correct answer.

Explanation

Echinococcus granulosus maintains a domestic cycle where dogs/canines are definitive hosts harboring adult tapeworms in their intestines. Eggs shed in dog feces are ingested by intermediate hosts (sheep, cattle, humans), developing into slow-growing, fluid-filled hydatid cysts (包虫囊) in the liver and lungs.

Question 18Veterinary epidemiology, zoonoses and food-chain protection

When an animal (such as cattle or sheep) is suspected of having died of Anthrax (炭疽, Bacillus anthracis), what is the most critical biosafety and veterinary public health rule regarding post-mortem handling?

  1. Post-mortem carcass dissection / autopsy is strictly prohibited to prevent vegetative bacilli from forming highly resistant, long-lived spores upon exposure to atmospheric oxygen (严禁就地解剖尸体，防止形成炭疽芽孢污染环境) Correct answer.
  2. Immediate thorough open-air autopsy must be performed on site to examine the spleen
  3. The meat should be distributed immediately to farm dogs to prevent spoilage
  4. The carcass should be washed with warm water and kept at room temperature for 7 days

Explanation

In an animal that has died of suspected Anthrax, Bacillus anthracis exists in vegetative form within tissues and unclotted blood. Opening the carcass exposes the bacilli to atmospheric oxygen, which immediately triggers the formation of durable, highly resistant spores that persist in soil for decades. Hence, carcass autopsy is strictly prohibited by law.

Question 19Species-aware pharmacology, anesthesia and welfare

In veterinary food safety and clinical pharmacology, the 'withdrawal time' (withholding period) of a veterinary pharmaceutical product administered to a food-producing animal is defined as:

  1. The duration of time an animal must be kept without food before receiving an oral anthelmintic
  2. The mandatory statutory interval between the last administration of a veterinary drug to an animal under normal conditions of use and the time when that animal can be slaughtered for human consumption, or its milk/eggs harvested, ensuring that residue levels have declined below the statutory Maximum Residue Limit (MRL) Correct answer.
  3. The time required for an animal to recover completely from general anesthesia before standing
  4. The shelf life of the reconstituted powdered veterinary vaccine before expiration

Explanation

A withdrawal requirement separates an actual medicine use from entry of the relevant animal product into the food chain under applicable rules and instructions. Species, formulation, route, use and current authorization matter. This definition supplies no universal number or automatic permission for an off-label use in a different jurisdiction.

Question 20Swiss veterinary duties, antimicrobial records and food-chain decisions

An adult dairy cow on pasture dies suddenly without prior signs. The carcass exhibits rapid decomposition, incomplete rigor mortis, marked abdominal bloating, and dark, tarry, uncoagulated blood oozing from the nostrils, mouth, and anus. What is the mandatory immediate action required by the attending veterinarian under Swiss veterinary legislation?

  1. Perform a full on-site post-mortem examination including opening the spleen and thoracic cavity
  2. Do NOT open the carcass; immediately notify the Cantonal Veterinary Office (Kantonstierarzt), secure the carcass from scavengers, and obtain a peripheral blood smear from the ear or tail vein for diagnostic confirmation of suspected Anthrax (Milzbrand) Correct answer.
  3. Transport the intact carcass immediately to the local abattoir for emergency slaughter evaluation
  4. Administer oral anthelmintics to the remaining herd and bury the carcass on the farm

Explanation

Anthrax (Bacillus anthracis / Milzbrand) is a dangerous zoonosis and notifiable high-consequence epizootic (auszurottende/hochpathogene Seuche). Under TSG, opening the carcass is strictly forbidden because vegetative bacilli sporulate when exposed to atmospheric oxygen, forming highly resistant spores that contaminate soil for decades. The veterinarian must immediately alert the Cantonal Veterinary Office and take a safe blood smear from a peripheral ear or tail vein.

Question 21Swiss veterinary duties, antimicrobial records and food-chain decisions

Within the actual IS ABV reporting scope, excluding medicines applied and acting exclusively at the surface, which listed recording function supports Swiss veterinary antibiotic-use monitoring?

  1. Tracking national milk prices and cattle export subsidies
  2. Recording annual bovine artificial insemination pedigrees
  3. Managing livestock grazing permits on public alpine pastures
  4. Mandatory electronic recording of all antibiotic prescriptions, direct administrations, and stock dispensing for groups and individual food-producing animals by practicing veterinarians within statutory deadlines Correct answer.

Explanation

IS ABV records relevant veterinary antibiotic prescribing under the current Swiss scope and reporting process. BLV identifies an exception for products applied and acting exclusively at the surface. This reporting exception does not erase other clinical records, and a completed entry does not certify that every prescription was appropriate.

Question 22Ruminant metabolism, herd evidence and reproductive health

A dairy cow shows mild colic, moderate drop in milk production, and a distinct percussion sound ('ping') in the upper right paralumbar fossa between the 10th rib and the tuber coxae. Rectal palpation reveals a blind-ended, rounded, smooth, gas- and fluid-filled organ extending caudally into the pelvic inlet whose apex can be manually moved. What is the diagnosis?

  1. Simple dilatation of the cecum (Cecal dilatation) Correct answer.
  2. Right abomasal volvulus with retroperitoneal rupture
  3. Torsion of the root of the mesentery
  4. Intussusception of the proximal jejunum

Explanation

Cecal dilatation is characterized by an accumulation of gas and liquid in the cecum, creating a resonant ping in the right paralumbar fossa and a palpable, soft, smooth, blind-ending cylinder (diameter 15–30 cm) pointing toward the pelvic inlet on rectal examination. If the apex rotates or twists (cecal volvulus), the organ becomes tense, painful, severely distended, and ischemic, requiring surgical typhlotomy or typhlectomy.

Question 23Ruminant metabolism, herd evidence and reproductive health

In Hoflund's classification of vagus indigestion syndrome in cattle, what functional defect defines Type III vagal indigestion, and what is its classic clinical and laboratory presentation?

  1. Failure of eructation (free gas bloat) resulting from acute vagal nerve trunk laceration
  2. Permanent pyloric outflow obstruction resulting in severe internal abomasal impaction, paradoxical aciduria, and marked hypochloremia Correct answer.
  3. Failure of omasal transport (anterior stenosis) with bradycardia and hyperchloremic acidosis
  4. Generalized abomasal atony with hyperperistalsis of the small intestine

Explanation

According to Hoflund's classification: Type I is failure of eructation (free-gas bloat); Type II is failure of omasal transport (anterior functional stenosis, leading to classic 'papple' shape rumen distension); Type III is permanent pyloric stenosis/outflow failure (posterior functional stenosis), characterized by severe abomasal distension/impaction, reflux of HCl into the rumen, marked hypochloremia, hypokalemic metabolic alkalosis, and dehydration; Type IV is partial pyloric outflow obstruction occurring during late pregnancy.

Question 24Ruminant metabolism, herd evidence and reproductive health

After prolonged recumbency following an initially treated metabolic illness, which listed secondary muscle complication needs consideration even if the cow is now alert and eating?

  1. Irreversible central demyelination caused by acute hypokalemia
  2. Diffuse vertebral osteomyelitis secondary to subclinical metritis
  3. Complete rupture of the cranial cruciate ligament in both stifles
  4. Ischemic muscle necrosis and compartment syndrome of the semitendinosus, semimembranosus, and gracilis muscles with compression neuropathy of the sciatic or peroneal nerve Correct answer.

Explanation

Prolonged recumbency can compromise muscle perfusion and contribute to pressure-related ischemic damage, which can impair the ability to rise after an initial metabolic problem improves. Other neurological, orthopedic and ongoing medical causes remain possible. This concern requires welfare-focused individual assessment rather than a guaranteed diagnosis from the elapsed time alone.

Question 25Ruminant metabolism, herd evidence and reproductive health

A 6-year-old Montbéliarde cow kept on alpine pasture in Valais develops chronic hematuria, progressive weight loss, and dysuria without pyrexia. Cystoscopy reveals multiple bleeding polypoid masses and hemangiosarcomas in the bladder mucosa. What is the underlying etiology of this condition (Enzootic Bovine Hematuria)?

  1. Chronic ingestion of Bracken fern (Pteridium aquilinum) containing ptaquiloside, acting synergistically with Bovine Papillomavirus type 2 (BPV-2) Correct answer.
  2. Infection with Corynebacterium renale causing ascending pyelonephritis
  3. Chronic toxicity from pyrrolizidine alkaloids present in Senecio jacobaea
  4. Immune-mediated glomerulonephritis triggered by subclinical BVDV infection

Explanation

Enzootic Bovine Hematuria is a chronic disease occurring in cattle grazing pastures infested with Bracken fern (Pteridium aquilinum). The carcinogen ptaquiloside induces DNA damage and immunosuppression, which acts synergistically with latent Bovine Papillomavirus type 2 (BPV-2) and BPV-1 in the urinary bladder to induce hemangiomas, hemangiosarcomas, and transitional cell carcinomas.

Question 26Ruminant metabolism, herd evidence and reproductive health

A 5-year-old Simmental cow presents with recurrent low-grade fever, weight loss, shifting lameness, bilateral jugular vein engorgement with visible presystolic pulsations, and a right-sided holosystolic murmur with maximum intensity over the 4th intercostal space. Which cardiac disorder is most consistent with these clinical findings?

  1. Congenital ventricular septal defect with aortic insufficiency
  2. Nutritional cardiomyopathy caused by selenium deficiency
  3. Cor pulmonale secondary to diffuse pulmonary emphysema
  4. Vegetative bacterial endocarditis primarily affecting the tricuspid valve, most frequently caused by Trueperella pyogenes Correct answer.

Explanation

In cattle, vegetative endocarditis predilects the right atrioventricular (tricuspid) valve (approx. 60–70% of cases), followed by the pulmonary or mitral valve. The primary causative pathogen is Trueperella pyogenes originating from chronic suppurative foci (foot abscesses, mastitis, liver abscesses). Tricuspid regurgitation produces a right-sided systolic murmur, jugular distension, positive jugular venous pulsation, hepatomegaly, and intermittent fever.

Question 27Ruminant metabolism, herd evidence and reproductive health

Which listed vector and clinical pattern is associated with bluetongue in a suitable ruminant differential, without assuming the actual status of a current Swiss outbreak?

  1. Transmission via stable flies (Stomoxys calcitrans); exclusive neurological disease in adult bulls
  2. Aerosol transmission indoors during winter; sudden watery diarrhea and milk drop with no mucosal lesions
  3. Tick-borne transmission; acute hemoglobinuria and splenomegaly in calves
  4. Transmission by Culicoides biting midges; fever, coronitis with lameness, facial/lip edema, tongue erosions, severe milk drop in cattle, and high mortality in sheep Correct answer.

Explanation

Bluetongue is an arbovirus transmitted by Culicoides biting midges (primarily C. obsoletus complex in Central Europe). Serotype BTV-3 (and BTV-8) causes severe clinical disease in sheep (facial edema, cyanotic tongue, hyperemic coronary bands, respiratory distress, mortality up to 20-30%) and substantial clinical signs in cattle (fever, coronitis, teat lesions, conjunctivitis, oral/nasal erosions, and drastic drops in milk yield).

Question 28Ruminant metabolism, herd evidence and reproductive health

A 14-month-old beef heifer on summer alpine pasture is found acutely dead without prior observed illness. Necropsy reveals marked subcutaneous crepitation over the right hindquarter, rancid-butter odor (butyric acid), and dark red-black, dry, spongy thigh musculature with gas bubbles. What is the definitive etiologic agent?

  1. Clostridium chauvoei (Blackleg / Rauschbrand) Correct answer.
  2. Bacillus anthracis (Anthrax / Milzbrand)
  3. Clostridium tetani (Tetanus / Wundstarrkrampf)
  4. Trueperella pyogenes (Suppurative myositis)

Explanation

Clostridium chauvoei is the classic etiological association for blackleg with the emphysematous necrotizing muscle pattern described. Other causes can overlap, so appearance does not replace suitable biosafe diagnostic confirmation. The answer does not import an incorrect phospholipase-C toxin identity or authorize routine dissection of every sudden death without hazard assessment.

Question 29Ruminant metabolism, herd evidence and reproductive health

A 3-year-old dairy cow housed in close contact with lambing sheep develops high fever (41.2°C), bilateral severe corneal opacity starting at the limbus and progressing centripetally, purulent bilateral keratoconjunctivitis, profuse mucopurulent nasal discharge with crusting erosions of the muzzle, enlarged prescapular lymph nodes, and terminal encephalitic signs. What is the most likely diagnosis?

  1. Infectious Bovine Keratoconjunctivitis (Moraxella bovis)
  2. Bovine Viral Diarrhea - Acute mucosal disease
  3. Malignant Catarrhal Fever (MCF) caused by Ovine Herpesvirus-2 (OvHV-2) Correct answer.
  4. Listeriosis (Listeria monocytogenes encephalomeningitis)

Explanation

Malignant Catarrhal Fever (MCF / Bösartiges Katarrhalfieber) in cattle in Europe is caused by Ovine Herpesvirus-2 (OvHV-2), an asymptomatic gammaherpesvirus endemic in domestic sheep. Transmission occurs via aerosol during sheep lambing. The virus causes generalized T-lymphocyte proliferation and necrotizing panvasculitis, producing high fever, panophthalmitis with centripetal corneal edema, mucosal crusting, generalized lymphadenopathy, and death.

Question 30Ruminant metabolism, herd evidence and reproductive health

An outbreak of acute respiratory distress in a group of 4-month-old indoor calves is characterized by tachypnea, pronounced expiratory dyspnea with abdominal grunt, subcutaneous emphysema over the withers, and high pyrexia. Post-mortem examination reveals heavy, non-collapsing, hyperinflated lungs with extensive interlobular and subpleural bullous emphysema. What is the primary viral pathogen?

  1. Bovine Parainfluenza-3 Virus (PI-3)
  2. Bovine Respiratory Syncytial Virus (BRSV) Correct answer.
  3. Bovine Adenovirus Type 3
  4. Bovine Coronavirus (BCoV)

Explanation

Bovine Respiratory Syncytial Virus (BRSV / Pneumovirus) targets ciliated bronchial and alveolar epithelial cells, causing syncytia formation, loss of ciliary clearance, and necrotizing bronchiolitis. Bronchiolar obstruction acts as a one-way valve, trapping air in alveoli and causing severe alveolar rupture, subpleural/interlobular emphysema, and dissecting subcutaneous emphysema over the back and neck.

Question 31Ruminant metabolism, herd evidence and reproductive health

A dairy farm experiences multiple calves with purulent otitis media (ear droop, head tilt), polyarthritis with joint distension, and adult cows with refractory, painless mastitis with brown clotted milk. Diagnostic investigations suspect Mycoplasma bovis. Why are beta-lactam antimicrobials (penicillins, cephalosporins) completely ineffective against Mycoplasma bovis?

  1. Mycoplasma bovis produces an inducible high-affinity AmpC beta-lactamase
  2. Mycoplasma bovis resides solely within intraerythrocytic vacuoles
  3. Mycoplasma bovis rapidly metabolizes beta-lactams as a nitrogen carbon source
  4. Mycoplasma species lack a peptidoglycan cell wall, the target of all beta-lactam antimicrobials Correct answer.

Explanation

Mycoplasma species are unique mollicute prokaryotes that completely lack a peptidoglycan cell wall, possessing only a triple-layered cholesterol-containing plasma membrane. Consequently, all antimicrobial classes targeting bacterial cell wall synthesis (penicillins, cephalosporins, carbapenems, vancomycin) have zero pharmacological efficacy. Effective treatments require protein- or nucleic acid-synthesis inhibitors (e.g., macrolides, fluoroquinolones, tetracyclines, florfenicol).

Question 32Ruminant metabolism, herd evidence and reproductive health

Young dairy heifers introduce cauliflower-like, hyperkeratotic cutaneous papillomas across the head, neck, and teats. What is the typical biological behavior and recommended standard clinical management of Bovine Papillomavirus (BPV) warts in heifers?

  1. Most cutaneous warts undergo spontaneous cell-mediated immune regression within 6 to 12 months; conservative observation or surgical removal of mechanically obstructive teat lesions is indicated Correct answer.
  2. Infection is invariably fatal within 30 days due to metastatic osteosarcoma
  3. Immediate intravenous chemotherapy with cisplatin is mandatory under Swiss veterinary law
  4. Total herd depopulation and carcass condemnation is required under TSG

Explanation

Many compatible cutaneous papillomas can regress with a developing immune response, but timing and outcome vary. Atypical, persistent, painful or interfering lesions need actual assessment rather than a guarantee of resolution within one calendar range. The pattern should be integrated with clinical evidence before every growth is assigned the same diagnosis or management.

Question 33Ruminant metabolism, herd evidence and reproductive health

A 3-week-old dairy calf presents with an irreducible, firm, painful swelling at the umbilicus, purulent discharge from the umbilical stalk, unthriftiness, and intermittent low-grade fever. Transabdominal ultrasound reveals an infected, thickened tubular structure (diameter > 15 mm) extending from the internal umbilical ring cranially toward the liver. What is the diagnosis and appropriate surgical management?

  1. Simple uncomplicated umbilical hernia; application of an external wooden clamp
  2. Omphaloarteritis; conservative antibiotic treatment only
  3. Omphalophlebitis (infection of the umbilical vein); surgical resection (marsupialization or complete excision) of the infected umbilical vein up to the liver capsule under general anesthesia or deep sedation with local anesthesia Correct answer.
  4. Urachal cyst; injection of 5% iodine into the bladder

Explanation

The umbilical vein runs cranially from the umbilicus into the falciform ligament and liver parenchyma. Infection (omphalophlebitis) produces a thickened, purulent tube visible ultrasonographically extending cranially. Treatment of choice is exploratory laparotomy with complete surgical excision of the infected umbilical vein. If the abscess extends into the liver parenchyma, the cranial vein stump is marsupialized to the ventral abdominal wall to allow continuous external drainage.

Question 34Ruminant reproductive physiology, calving and udder health

Which environmental mastitis pathogen is capable of thriving in deep organic straw bedding, frequently produces recurrent clinical flares with high somatic cell counts, and often exhibits persistent colonization amenable to extended dry period therapy?

  1. Streptococcus agalactiae
  2. Trueperella pyogenes
  3. Corynebacterium bovis
  4. Streptococcus uberis Correct answer.

Explanation

Streptococcus uberis is a versatile environmental and opportunistic mastitis pathogen whose primary reservoir is organic bedding (particularly straw), pasture soil, and bovine skin. It produces capsule and biofilm factors, allowing it to adhere to and invade mammary epithelial cells. It accounts for a large proportion of clinical and subclinical mastitis cases during both the dry period and early lactation.

Question 35Ruminant reproductive physiology, calving and udder health

A dairy cow 5 days postpartum develops acute toxic mastitis in the right rear quarter. The cow is recumbent with hypothermia (37.6°C), severe tachycardia (120 bpm), scleral injection, cold extremities, watery serum-like milk secretion, and ruminal atony. What is the central pathophysiological cascade driving this clinical crisis, and what is the primary therapeutic priority?

  1. Exotoxin-induced osteomyelitis; immediate surgical amputation of the digit
  2. Lipopolysaccharide (LPS / endotoxin) release from dying Escherichia coli triggering massive TNF-alpha, IL-1, and nitric oxide surge leading to septic distributive shock; primary therapy is aggressive IV isotonic/hypertonic fluid resuscitation, NSAIDs (e.g., flunixin or ketoprofen), and frequent udder stripping Correct answer.
  3. Ascending Clostridium tetani neurotoxin release; administration of 500,000 IU tetanus antitoxin
  4. Acute hypovitaminosis E causing hepatic rupture; immediate slaughter

Explanation

Acute coliform mastitis (Escherichia coli or Klebsiella pneumoniae) causes rapid lysis of Gram-negative bacterial outer membranes, releasing large amounts of lipid A (LPS / endotoxin) into circulation. Endotoxemia stimulates macrophages to release pro-inflammatory cytokines (TNF-a, IL-1, IL-6) and nitric oxide, producing vasodilation, capillary leakage, hypovolemic/distributive shock, and multi-organ failure. Immediate aggressive intravenous fluid resuscitation combined with NSAIDs is life-saving.

Question 36Ruminant reproductive physiology, calving and udder health

A dairy cow 4 days postpartum develops puerperal toxic metritis characterized by high fever (40.8°C), depression, marked drop in milk yield, and foul-smelling, reddish-brown watery lochia. Why is routine intrauterine infusion of irritating antiseptics (e.g., Lotagen or iodine solutions) contraindicated during the first 10 days postpartum?

  1. Intrauterine antiseptics stimulate excessive progesterone secretion from the corpus luteum
  2. The large, thin-walled, friable puerperal myometrium and disrupted caruncular epithelium permit systemic absorption of toxins, risk uterine rupture, and chemical irritants destroy natural phagocytic uterine defenses and induce severe tissue necrosis Correct answer.
  3. Intrauterine infusions permanently alter the genetic karyotype of future blastocysts
  4. Swiss TAMV law requires all cows with lochia to receive mandatory surgical hysterectomy

Explanation

In acute puerperal metritis (<10 days postpartum), the myometrial wall is exceptionally thin, hyperemic, and friable. Infusion of caustic or hypertonic solutions risks chemical necrosis, myometrial perforation, and impaired neutrophil phagocytosis. Furthermore, large fluid volumes cannot reach deep bacterial microabscesses in the myometrium. The evidence-based medical treatment is systemic antimicrobial therapy (e.g., ceftiofur, ampicillin, or penicillin) alongside NSAIDs and supportive fluids.

Question 37Ruminant reproductive physiology, calving and udder health

What is the primary physiological mechanism responsible for the normal detachment and expulsion of fetal membranes (placenta) within 6 to 12 hours after physiological parturition in cattle?

  1. Acute elevation of serum progesterone causing myometrial tetany
  2. Mechanical pulling by the weight of the standing calf on the umbilical cord
  3. Immediate enzymatic digestion of cotyledons by ruminal microflora
  4. A surge in maternal uterine collagenase activity and leukocyte recognition/breakdown of the fetal-maternal collagen bridge (syndesmochorial detachment) accompanied by strong myometrial contractions Correct answer.

Explanation

Normal placental detachment requires: 1) Decreased progesterone and increased estrogen/PGF2alpha before calving; 2) Exsanguination of fetal cotyledonary villi after umbilical rupture; 3) Activation of maternal and fetal proteases/collagenases; 4) A cell-mediated immune recognition (MHC class I disparity) where maternal leukocytes actively attack and degrade the caruncular-cotyledonary interface. Impairment of this immune/enzymatic cascade results in retained fetal membranes (Retentio secundinarum).

Question 38Ruminant reproductive physiology, calving and udder health

In beef breeding herds utilizing natural service bulls, what are the characteristic transmission, clinical presentation, and diagnostic sampling procedures for Tritrichomonas foetus and Campylobacter fetus subsp. venerealis?

  1. Venereal transmission during coitus; asymptomatic carrier bulls harbor pathogens in the preputial fornix and smegma; infected cows exhibit early embryonic death, delayed return to estrus, low pregnancy rates, and occasional post-coital pyometra; diagnosed by preputial washings/scraping for culture and qPCR Correct answer.
  2. Airborne transmission in winter barns; acute abortions in month 9 with massive placental calcification; diagnosed by milk serology
  3. Transmission via contaminated drinking water; acute orchitis in bulls with total sterility; diagnosed by liver biopsy
  4. Transmission by biting flies; persistent high fever in pregnant cows; diagnosed by skin scraping

Explanation

Both Tritrichomonas foetus (a flagellated protozoan) and Campylobacter fetus subsp. venerealis (a microaerophilic Gram-negative bacterium) are obligate venereal pathogens. Mature bulls (>3–4 years) develop chronic, lifelong, asymptomatic carrier states in the crypts of the preputial and penile mucosa. In cows, infection causes subacute endometritis, early embryonic death, irregular estrus return intervals, and herd infertility. Diagnosis requires preputial scrapings/washings examined via real-time PCR or culture.

Question 39Ruminant reproductive physiology, calving and udder health

In a supplied aligned 21-day reproductive-cohort model, how is pregnancy rate related to the submission rate and conception rate, rather than asserting one universal excellent herd target?

  1. Calving Interval divided by 365 days; target > 95%
  2. Total pregnant cows divided by total dry cows; target > 80%
  3. The percentage of eligible non-pregnant cows that become pregnant in a 21-day cycle (Calculated as: 21-day Insemination/Submission Rate x Conception Rate); target >= 20% to 25% Correct answer.
  4. Number of live heifer calves born per 100 inseminations; target > 60%

Explanation

When the cohort and time definitions are aligned, the fraction submitted multiplied by the fraction conceiving among those submitted gives the fraction becoming pregnant in that period. Percentages must be converted consistently when multiplying. Actual performance depends on eligibility, records and biological context; this identity does not establish one universal excellent target.

Question 40Small-ruminant and camelid species distinctions

What is the primary epidemiological rationale for implementing Targeted Selective Treatment (TST) strategies rather than whole-flock blanket anthelmintic deworming in small ruminant flocks?

  1. To reduce the total volume of water consumed by sheep on pasture
  2. To eliminate all nematode eggs from the farm within 24 hours
  3. To stimulate active immunity against Clostridium tetani
  4. To maintain an unselected nematode population in 'refugia' (worms unexposed to anthelmintics), thereby diluting resistant alleles and significantly slowing the development of anthelmintic resistance Correct answer.

Explanation

Blanket whole-flock deworming destroys susceptible parasites, leaving only resistant worms to reproduce and contaminate pasture, accelerating multi-drug anthelmintic resistance. Targeted Selective Treatment (TST)-deworming only clinically compromised animals (e.g., FAMACHA scores 4–5, poor body condition, or low growth rates)-preserves a substantial parasite population in 'refugia' (both in untreated animals and on pasture). This maintains susceptible genes in the parasite gene pool.

Question 41Small-ruminant and camelid species distinctions

A goat buck presents with a painless, cold, well-encapsulated fluctuating swelling (diameter 8 cm) located at the parotid lymph node. Aspiration yields thick, greenish-white, non-odorous cheesy pus. Histopathology reveals characteristic concentric laminations ('onion-ring' appearance). What is the causative organism of Caseous Lymphadenitis (CLA / Pseudotuberkulose)?

  1. Mycobacterium bovis
  2. Streptococcus equi subsp. zooepidemicus
  3. Corynebacterium pseudotuberculosis Correct answer.
  4. Staphylococcus aureus subsp. anaerobius

Explanation

Caseous Lymphadenitis (Pseudotuberkulose) in sheep and goats is caused by Corynebacterium pseudotuberculosis, a Gram-positive facultative intracellular bacterium. It enters through shearing or skin wounds, spreads via lymphatics to regional lymph nodes, and forms chronic granulomas characterized by inspissated, dry, caseous exudate with concentric laminar fibrous rings ('onion-ring' pattern on cross-section).

Question 42Small-ruminant and camelid species distinctions

A flock of Texel sheep accidentally fed cattle mineral concentrate containing 35 mg/kg of copper for 6 weeks develops acute anorexia, depression, severe icterus, dark port-wine-colored urine (hemoglobinuria), and death in 4 ewes. Necropsy shows yellow-orange liver and enlarged, black-blue ('gunmetal') kidneys. What is the pathophysiological mechanism of chronic copper toxicosis in sheep?

  1. Sheep have a low biliary excretion capacity for copper; excess dietary copper accumulates silently in hepatic lysosomes for weeks until hepatic storage capacity is overwhelmed; sudden release of ionic copper into the bloodstream causes massive intravascular hemolysis, methemoglobinemia, and acute hemoglobinuric nephrosis Correct answer.
  2. Copper binds directly to cardiac muscle acetylcholine receptors, causing acute asystole
  3. Copper causes immediate ulceration of the reticular groove
  4. Copper stimulates excessive production of parathyroid hormone, causing acute hypercalcemia

Explanation

Sheep (especially Texel, Suffolk, and East Friesian breeds) are uniquely sensitive to copper toxicity due to limited biliary copper excretion. Ingested copper accumulates silently in hepatic lysosomes. When hepatic capacity is exceeded (often triggered by stress, transport, or handling), massive amounts of copper are released into circulation, causing acute lipid peroxidation of red blood cell membranes, severe intravascular hemolysis, methemoglobinemia, icterus, and tubular blockage by hemoglobin ('gunmetal' kidneys).

Question 43Small-ruminant and camelid species distinctions

In the genetic selection for resistance against Classical Scrapie (TSE) in sheep under European and Swiss breeding programs, which PrP (prion protein) codon 136/154/171 genotype confers the highest resistance against classical scrapie?

  1. VRQ / VRQ (Valine-Arginine-Glutamine)
  2. ARQ / VRQ (Alanine-Arginine-Glutamine / Valine-Arginine-Glutamine)
  3. AHQ / ARQ (Alanine-Histidine-Glutamine / Alanine-Arginine-Glutamine)
  4. ARR / ARR (Alanine-Arginine-Arginine / Alanine-Arginine-Arginine) Correct answer.

Explanation

Among the listed genotypes, ARR/ARR is associated with strong relative resistance to classical scrapie in the relevant sheep-breeding context. It is not an absolute guarantee against every prion infection, and it does not ensure resistance to atypical scrapie. The disease entity and current breeding framework must be specified.

Question 44Small-ruminant and camelid species distinctions

A 3-month-old rapidly growing fattening lamb grazing rich pasture dies suddenly. Necropsy reveals soft, autolyzed kidneys ('pulpy kidney'), straw-colored pericardial effusion with fibrin clots, and glycosuria on urinalysis. What is the diagnosis and causative clostridial toxin?

  1. Black disease caused by Clostridium novyi Type B alpha toxin
  2. Enterotoxemia (Pulpy Kidney Disease) caused by Clostridium perfringens Type D epsilon toxin Correct answer.
  3. Tetanus caused by Clostridium tetani tetanospasmin
  4. Malignant edema caused by Clostridium septicum

Explanation

Enterotoxemia (Pulpy Kidney Disease) in sheep and goats is caused by Clostridium perfringens Type D. Rapid intake of starch or rich pasture allows C. perfringens to proliferate in the intestine, producing the protoxin epsilon, which is activated by trypsin into a potent vascular toxin. Epsilon toxin increases endothelial permeability, producing brain edema, pericardial effusion, rapid post-mortem renal cortical autolysis ('pulpy kidney'), and marked glucosuria.

Question 45Ruminant 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 46Ruminant 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 47Ruminant 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 48Ruminant 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 49Ruminant 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 50Ruminant 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.