Large Animal Medicine Flashcards

Which of the following best describes the pathophysiology of 'hardware disease' (traumatic reticuloperitonitis) in cattle?

Answer: Ingested metallic foreign body penetrates the reticulum wall causing peritonitis

Hardware disease occurs when ingested metal (wire, nails) penetrates the reticulum, causing localized or diffuse peritonitis; a magnet placed in the reticulum is the standard prevention.

A foal is born to a mare with a history of producing isoerythrolysis-affected foals. Which blood type incompatibility is MOST commonly involved in equine neonatal isoerythrolysis?

Answer: Aa and Qa blood group antigens

Equine neonatal isoerythrolysis most commonly involves Aa and Qa blood group antigens, where an Aa- or Qa-negative mare becomes sensitized and produces antibodies passed through colostrum.

A cow presents with sudden blindness, opisthotonus, and pressing behavior. CSF analysis shows glucose depletion and elevated lactate. What is the most likely diagnosis?

Answer: Polioencephalomalacia (cerebrocortical necrosis)

Polioencephalomalacia results from thiamine deficiency or sulfur toxicosis causing cerebrocortical necrosis, presenting with blindness, ataxia, and opisthotonus; it responds to IV thiamine.

During a pre-purchase examination of a horse, bilateral tarsal periarticular remodeling is noted on radiographs with evidence of distal intertarsal and tarsometatarsal joint fusion. This is consistent with which condition?

Answer: Bone spavin (distal tarsal osteoarthritis)

Bone spavin refers to osteoarthritis of the distal tarsal joints (centrodistal and tarsometatarsal), which can progress to bony fusion; it is a common cause of hindlimb lameness in horses.

Which of the following best describes the mechanism of ionophore toxicity (e.g., monensin) in cattle?

Answer: Disruption of mitochondrial cation transport leading to cardiac and skeletal muscle necrosis

Ionophores disrupt mitochondrial sodium/potassium transport, causing energy depletion and cell death in cardiac and skeletal muscle, leading to myopathy and heart failure.

A goat kid presents at 3 days of age with bloody diarrhea and sudden death of littermates. Gram stain of intestinal content shows large gram-positive rods. Which pathogen is most likely responsible?

Answer: Clostridium perfringens type C

Clostridium perfringens type C produces beta-toxin causing hemorrhagic enteritis and rapid death in neonatal ruminants; large gram-positive rods in intestinal content support this diagnosis.

A Standardbred trotter is presented for bilateral hindlimb weakness and muscle wasting. EMG reveals abnormal spontaneous activity in epaxial muscles. PSSM-2 testing is negative. Which condition should be considered?

Answer: Equine motor neuron disease (EMND)

Equine motor neuron disease causes lower motor neuron signs with muscle atrophy, abnormal EMG, and is associated with vitamin E deficiency; retinal pigment changes are pathognomonic.