ICVA NAVLE EXAM 1 2025/2026 WITH 100% ACCURATE ANSWERS
Fifteen of a group of 200, 7 month old feedlot calves are lame. The calves arrived at the feedlot
approximately one month ago, and one week later, 40 of the animals developed pneumonia. These
calves were treated with oxytetracycline, and the pneumonia appeared to resolve. On physical
examination, the affect calves have swellings in the carpi, tarsi, and stifles with distension of associated
tendon sheaths, and stiff gait. Two calves are euthanized. Postmortem eamination shows fibrinous
pleuritis and papillary muscle necrosis. Which of the following organisms is the most likely cuase of
these signs?
a) arcanobacterium (actinomyces) pyogenes
b) histophilus somni
c ) mannheimia hemolytica
d) pasteurella multocida
e) salmonella thyphimurium - (ANSWER)B) histophilus somni
Histophilus somni is a well known cause of systemic disease in feedlot cattle, including respiratory
disease, speticemia, and polyarthritis. In this case, the calves initially developed pneumonia, and now
soe of them show signs of lameness, joint swelling, and stiff gait, which are consistent with septic
arthritis, and polyarthritis that can occur after a histophilus somni infection
- additionally the post mortem finding of fibrinous pleuritis and papillary muscle necrosis also strongly
suggest histophilus soni as the causative agent.
-Known to cause arthritis, pleuritis, myocarditis, and septicemia in calves
What is hyperkalemic periodic paralysis in a horse - (ANSWER)-a genetic disorder that affects muscles
causing episodes of muscle weakness or paralysis.
-It is autosomal dominant
What is the cause of hyperkalemic periodic paralysis - (ANSWER)THe disorder is caused by a mutation in
the sodium channel gene, leading to increased potassium levels in the blood. This affects the electrical
activity of muscle cells, causing the muscles to contract abnormally
What are symptoms of hyperkalemic periodic paralysis in horses - (ANSWER)-muscle twitching or
trembling
-weakness or partial paralysis especially in hindquarters
,ICVA NAVLE EXAM 1 2025/2026 WITH 100% ACCURATE ANSWERS
-episodes of muscle stiffness
-respiratory issues in severe cases
-horse remains alert
what are triggers of hyperkalemic periodic paralysis - (ANSWER)-high potassium intake from feed such
as alfalfa, molasses or certain grains
-stress, exercise or fasting
how would you manage hyperkalemic periodic paralysis - (ANSWER)-dietary modification like feeding
low potassium diets and aoiding alfala and monitor potassium intake
-medicate with acetazolamide and hydrochlorothiazide
-consistent exercise and minimize stress
A 3-year old Percheron mare is undergoing routine dental evaluation. Physical examination shows
bilateral prolapse of the nictitating membrane and muscle fasciculations of the neck, shoulders, and
flank. During examination, the mare's hindlimbs give way, and she leans back in a dog-sitting posture.
Rectal temperature is 100.4 degrees F (38.0 degrees C), heart rate is 60 beats/min, and respiratory rate
is 30 breaths/min.
Which of the following is the most likely diagnosis?
A) Equine degenerative myeloneuropathy
B) Equine motor neuron disease
C) Exertional rhabdomyolysis
D) Hyperkalemic periodic paralysis
E) Tetanus - (ANSWER)D) hyperkalemic periodic paralysis
HYPP leads to episodes of periodic muscle weakness or paralysis.
-Prolapse of the nictitating membrane is characteristic of HYPP due to muscle weakness in the face
,ICVA NAVLE EXAM 1 2025/2026 WITH 100% ACCURATE ANSWERS
-Weakness and collapse suggest muscle paralysis or severe weakness, dog sitting posture strongly
supports this
A 3-year old Percheron mare is undergoing routine dental evaluation. Physical examination shows
bilateral prolapse of the nictitating membrane and muscle fasciculations of the neck, shoulders, and
flank. During examination, the mare's hindlimbs give way, and she leans back in a dog-sitting posture.
Rectal temperature is 100.4 degrees F (38.0 degrees C), heart rate is 60 beats/min, and respiratory rate
is 30 breaths/min.
This is a case of HYPP, why would Equine Degenerative Myeloneuropathy be incorrect - (ANSWER)EDM
is a neurodegenerative disease that causes progresse ataxia ( incoordination) and weakness in young
horses, particularly those deficient in vitamin E.
Although it causes weakness, EDM is more associated with ataxia ( uncoordinated movement) rather
than acute muscle fasciculations or prolapse of the nictitating membrane. It is a chronic, progressive
condition, unlike the episodic nature of HYPP
A 3-year old Percheron mare is undergoing routine dental evaluation. Physical examination shows
bilateral prolapse of the nictitating membrane and muscle fasciculations of the neck, shoulders, and
flank. During examination, the mare's hindlimbs give way, and she leans back in a dog-sitting posture.
Rectal temperature is 100.4 degrees F (38.0 degrees C), heart rate is 60 beats/min, and respiratory rate
is 30 breaths/min.
This is a case of HYPP, why would Equine Motor Neuron Disease be incorrect - (ANSWER)EMND is a
neurodegeneratie disorder and is associated with vitamin E deficiency
-EMND causes muscle atrophy and weakness, primarily affecting posture and gait over time. However it
does not typically cause acute episodes of weakness with fasciculation and prolapse of the third eyelid
like HYPP does. EMND is also more chronic in its progression, not episodic.
A 3-year old Percheron mare is undergoing routine dental evaluation. Physical examination shows
bilateral prolapse of the nictitating membrane and muscle fasciculations of the neck, shoulders, and
flank. During examination, the mare's hindlimbs give way, and she leans back in a dog-sitting posture.
Rectal temperature is 100.4 degrees F (38.0 degrees C), heart rate is 60 beats/min, and respiratory rate
is 30 breaths/min.
, ICVA NAVLE EXAM 1 2025/2026 WITH 100% ACCURATE ANSWERS
This is a case of HYPP, why would Exertional Rhabdomyolysis be incorrect - (ANSWER)ER is a condition
where muscle damage occurs after exercise, resulting in muscle stiffness, pain and potentially dark urine
due to myoglobin release.
-While muscle fasciculations and hind limb weakness could suggest muscle damage, ER is typically
associated with exercise induced pain and stiffness rather than sudden collapse. Additionally, prolapse
of nictitating membranes is not a feature of ER
A 3-year old Percheron mare is undergoing routine dental evaluation. Physical examination shows
bilateral prolapse of the nictitating membrane and muscle fasciculations of the neck, shoulders, and
flank. During examination, the mare's hindlimbs give way, and she leans back in a dog-sitting posture.
Rectal temperature is 100.4 degrees F (38.0 degrees C), heart rate is 60 beats/min, and respiratory rate
is 30 breaths/min.
This is a case of HYPP, why would Tetanus be incorrect - (ANSWER)_Tetanus is caused by neurotoxin
produced by Clostridium tetani leading to rigid paralysis, muscle spasms and an exaggerated response to
stimuli
-Tetanus causes rigid muscle contraction and spasms rather than muscle weakness seen in this case.
Prolapse of the nictitating membrane can be seen in tetanus, but the muscle fasciculations and collapse
described are ore consistent with HYPP than the rigid paralysis of tetanus
A 6 year old male cocker spaniel dog has recurrent otitis externa. Microscopic examination of a smear of
purulent discharge from the ear shows large numbers of rod shaped bacteria. Which of the following is
the most likely causative organism?
A) escheria coli
b) klebsiella spp
c) pasteurella multocida
d) pseudomonas aeruginosa
e) staphylococcus intermedius - (ANSWER)d) pseudomonas aeruginosa
Pseudomonas aeruginosa is a gram-negative, rod-shaped bacterium commonly associated with
recurrent and chronic otitis externa in dogs, especially when standard treatment fails. It is known for its
resistance to many antibiotics and its ability to form biofilms, making infections persistent and difficult
to treat.
Fifteen of a group of 200, 7 month old feedlot calves are lame. The calves arrived at the feedlot
approximately one month ago, and one week later, 40 of the animals developed pneumonia. These
calves were treated with oxytetracycline, and the pneumonia appeared to resolve. On physical
examination, the affect calves have swellings in the carpi, tarsi, and stifles with distension of associated
tendon sheaths, and stiff gait. Two calves are euthanized. Postmortem eamination shows fibrinous
pleuritis and papillary muscle necrosis. Which of the following organisms is the most likely cuase of
these signs?
a) arcanobacterium (actinomyces) pyogenes
b) histophilus somni
c ) mannheimia hemolytica
d) pasteurella multocida
e) salmonella thyphimurium - (ANSWER)B) histophilus somni
Histophilus somni is a well known cause of systemic disease in feedlot cattle, including respiratory
disease, speticemia, and polyarthritis. In this case, the calves initially developed pneumonia, and now
soe of them show signs of lameness, joint swelling, and stiff gait, which are consistent with septic
arthritis, and polyarthritis that can occur after a histophilus somni infection
- additionally the post mortem finding of fibrinous pleuritis and papillary muscle necrosis also strongly
suggest histophilus soni as the causative agent.
-Known to cause arthritis, pleuritis, myocarditis, and septicemia in calves
What is hyperkalemic periodic paralysis in a horse - (ANSWER)-a genetic disorder that affects muscles
causing episodes of muscle weakness or paralysis.
-It is autosomal dominant
What is the cause of hyperkalemic periodic paralysis - (ANSWER)THe disorder is caused by a mutation in
the sodium channel gene, leading to increased potassium levels in the blood. This affects the electrical
activity of muscle cells, causing the muscles to contract abnormally
What are symptoms of hyperkalemic periodic paralysis in horses - (ANSWER)-muscle twitching or
trembling
-weakness or partial paralysis especially in hindquarters
,ICVA NAVLE EXAM 1 2025/2026 WITH 100% ACCURATE ANSWERS
-episodes of muscle stiffness
-respiratory issues in severe cases
-horse remains alert
what are triggers of hyperkalemic periodic paralysis - (ANSWER)-high potassium intake from feed such
as alfalfa, molasses or certain grains
-stress, exercise or fasting
how would you manage hyperkalemic periodic paralysis - (ANSWER)-dietary modification like feeding
low potassium diets and aoiding alfala and monitor potassium intake
-medicate with acetazolamide and hydrochlorothiazide
-consistent exercise and minimize stress
A 3-year old Percheron mare is undergoing routine dental evaluation. Physical examination shows
bilateral prolapse of the nictitating membrane and muscle fasciculations of the neck, shoulders, and
flank. During examination, the mare's hindlimbs give way, and she leans back in a dog-sitting posture.
Rectal temperature is 100.4 degrees F (38.0 degrees C), heart rate is 60 beats/min, and respiratory rate
is 30 breaths/min.
Which of the following is the most likely diagnosis?
A) Equine degenerative myeloneuropathy
B) Equine motor neuron disease
C) Exertional rhabdomyolysis
D) Hyperkalemic periodic paralysis
E) Tetanus - (ANSWER)D) hyperkalemic periodic paralysis
HYPP leads to episodes of periodic muscle weakness or paralysis.
-Prolapse of the nictitating membrane is characteristic of HYPP due to muscle weakness in the face
,ICVA NAVLE EXAM 1 2025/2026 WITH 100% ACCURATE ANSWERS
-Weakness and collapse suggest muscle paralysis or severe weakness, dog sitting posture strongly
supports this
A 3-year old Percheron mare is undergoing routine dental evaluation. Physical examination shows
bilateral prolapse of the nictitating membrane and muscle fasciculations of the neck, shoulders, and
flank. During examination, the mare's hindlimbs give way, and she leans back in a dog-sitting posture.
Rectal temperature is 100.4 degrees F (38.0 degrees C), heart rate is 60 beats/min, and respiratory rate
is 30 breaths/min.
This is a case of HYPP, why would Equine Degenerative Myeloneuropathy be incorrect - (ANSWER)EDM
is a neurodegenerative disease that causes progresse ataxia ( incoordination) and weakness in young
horses, particularly those deficient in vitamin E.
Although it causes weakness, EDM is more associated with ataxia ( uncoordinated movement) rather
than acute muscle fasciculations or prolapse of the nictitating membrane. It is a chronic, progressive
condition, unlike the episodic nature of HYPP
A 3-year old Percheron mare is undergoing routine dental evaluation. Physical examination shows
bilateral prolapse of the nictitating membrane and muscle fasciculations of the neck, shoulders, and
flank. During examination, the mare's hindlimbs give way, and she leans back in a dog-sitting posture.
Rectal temperature is 100.4 degrees F (38.0 degrees C), heart rate is 60 beats/min, and respiratory rate
is 30 breaths/min.
This is a case of HYPP, why would Equine Motor Neuron Disease be incorrect - (ANSWER)EMND is a
neurodegeneratie disorder and is associated with vitamin E deficiency
-EMND causes muscle atrophy and weakness, primarily affecting posture and gait over time. However it
does not typically cause acute episodes of weakness with fasciculation and prolapse of the third eyelid
like HYPP does. EMND is also more chronic in its progression, not episodic.
A 3-year old Percheron mare is undergoing routine dental evaluation. Physical examination shows
bilateral prolapse of the nictitating membrane and muscle fasciculations of the neck, shoulders, and
flank. During examination, the mare's hindlimbs give way, and she leans back in a dog-sitting posture.
Rectal temperature is 100.4 degrees F (38.0 degrees C), heart rate is 60 beats/min, and respiratory rate
is 30 breaths/min.
, ICVA NAVLE EXAM 1 2025/2026 WITH 100% ACCURATE ANSWERS
This is a case of HYPP, why would Exertional Rhabdomyolysis be incorrect - (ANSWER)ER is a condition
where muscle damage occurs after exercise, resulting in muscle stiffness, pain and potentially dark urine
due to myoglobin release.
-While muscle fasciculations and hind limb weakness could suggest muscle damage, ER is typically
associated with exercise induced pain and stiffness rather than sudden collapse. Additionally, prolapse
of nictitating membranes is not a feature of ER
A 3-year old Percheron mare is undergoing routine dental evaluation. Physical examination shows
bilateral prolapse of the nictitating membrane and muscle fasciculations of the neck, shoulders, and
flank. During examination, the mare's hindlimbs give way, and she leans back in a dog-sitting posture.
Rectal temperature is 100.4 degrees F (38.0 degrees C), heart rate is 60 beats/min, and respiratory rate
is 30 breaths/min.
This is a case of HYPP, why would Tetanus be incorrect - (ANSWER)_Tetanus is caused by neurotoxin
produced by Clostridium tetani leading to rigid paralysis, muscle spasms and an exaggerated response to
stimuli
-Tetanus causes rigid muscle contraction and spasms rather than muscle weakness seen in this case.
Prolapse of the nictitating membrane can be seen in tetanus, but the muscle fasciculations and collapse
described are ore consistent with HYPP than the rigid paralysis of tetanus
A 6 year old male cocker spaniel dog has recurrent otitis externa. Microscopic examination of a smear of
purulent discharge from the ear shows large numbers of rod shaped bacteria. Which of the following is
the most likely causative organism?
A) escheria coli
b) klebsiella spp
c) pasteurella multocida
d) pseudomonas aeruginosa
e) staphylococcus intermedius - (ANSWER)d) pseudomonas aeruginosa
Pseudomonas aeruginosa is a gram-negative, rod-shaped bacterium commonly associated with
recurrent and chronic otitis externa in dogs, especially when standard treatment fails. It is known for its
resistance to many antibiotics and its ability to form biofilms, making infections persistent and difficult
to treat.
