NAVLE MAIN EXAMINATION QUESTIONS AND
ANSWERS SET A+
✔✔A 2-year old heifer is presented who died the night before. She was stunted
compared to her herdmates, and had a 3-week history of poor appetite, unthriftiness,
diarrhea. Necropsy reveals that the abomasum is edematous and covered in small
umbilicated nodules 1-2 mm in diameter (cobblestone or "Moroccan leather"
appearance).
Several other younger cows in this Spring-calving herd look unthrifty and have diarrhea
too. What is the plan of action?
A - Cull the sick cows, Keep horses off same pasture 3 months
B - Deworm cows post-calving, calves by midsummer, all stock in fall
C - Treat affected heifers with Albendazole
D - Treat affected heifers with Ivermectin, repeat in 6 months
E - Treat herd with Amprolium, repeat q 5 weeks - ✔✔B
Treatment includes deworming cows post-calving, calves by midsummer, all stock in
fall.
An abomasum with a cobblestone or "Moroccan leather" appearance is pathognomonic
for Ostertagia , one of the three stomach worms of cattle. These worms remain dormant
in the gastric glands of the abomasum, emerging in the spring. Rx is based on regular
deworming of whole herd (2-4 times/year). Ivermectin or high dose
Albendazole/Fenbendazole, given repeatedly can help treat the dormant ("hypobiotic")
Ostertagia in the gastric glands.
Amprolium is your treatment of choices for calves and cows with Coccidiosis.
✔✔A practice is using an FeLV test with a sensitivity of 90% and a specificity of 95%.
Assuming the prevalence of feline leukemia in the area is 5%, what is the predictive
value positive (PVP) of the test?
,A - 45%
B - 48%
C - 55%
D - 88%
E - 90% - ✔✔It is 48%. The trick with this kind of question is to pick an imaginary
number of animals that you test, like 1000, and fill out your 2x2 table from there. Follow
the links to see diagrams step by step.
If prev is 5% then there must be 50/1000 cats with FeLV and 950 cats that are disease-
free.
A 90% sensitive test will correctly call 45/50 positive (box "a"), and IN-correctly call 5/50
negative, (box "c": these are the false negs).
If 50/1000 animals are infected, then 950/1000 are disease-free. Your 95% specific test
will correctly call 902/950 disease-free (box "d": 0.95 X 950=902) and IN-correctly call
48/950 positive, (box "b": these are the false pos).
Now your a,b,c,d boxes are all filled, it is easy to calculate PVP
=a/(a+b)=45/(45+48)=48%
✔✔A 4 year old mare has bilateral swelling and drainage of the mandibular lymph
nodes. Rectal temperature is 101.8F (38.8 C). Which of the following is the most
appropriate plan for this horse?
A - Administer corticosteroids
B - Culture the discharge for bacteria
C - Inform the state veterinarian
D - Administer penicillin - ✔✔B
The correct answer is to culture the discharge for bacteria. The most likely diagnosis for
this horse is equine strangles. Strangles most commonly affects younger horses (<5
years of age), but can cause disease in any age horse. The etiologic agent of this
disease is Streptococcus equi subsp. equi. The diagnostic test of choice to confirm this
is bacterial culture. While awaiting culture results, the horse should be separated from
any other horses, as strangles is highly contagious to other horses. Antibiotic therapy is
controversial and thought to lengthen the course of disease rather than shorten it when
given at this stage; also, it may possibly interfere with the natural immunity acquired
from natural infection. This is not a reportable disease.
✔✔When performing a subtotal colectomy on a feline patient, what blood vessel limits
the amount of colon that you are able to remove?
A - Pudendal artery
B - Caudal mesenteric artery
,C - Left colic artery
D - Ileocolic artery - ✔✔D
The correct answer is ileocolic artery. The site for colonic resection is limited by tension
on the ileocolic artery when trying to suture your new end of colon to the rectum.
Sometimes the tension is too great and instead of a colocolic anastomosis, an ileocolic
anastomosis must be performed. Essentially you are trying to connect a section of
ascending colon to the rectum. Now that can be pretty far! Performing an ileocolic
anastomosis is not ideal because you eliminate the ileocecal valve, and that may
predispose the animal to bacterial overgrowth. The caudal mesenteric artery gives
branches to the rectum and descending colon. The left colic artery also feeds the
descending colon. The pudendal artery supplies the external genitalia. The ileocolic
artery provides blood supply to the ascending and transverse colon.
✔✔Foal heat diarrhea is typically associated with which choice?
A - Hemorrhagic enteritis
B - Neutropenia and fever
C - Decreased suckling
D - Alterations in diet
E - Warm and humid weather - ✔✔D
Mild, self-limiting diarrhea in a foal 7-14 days of age is called foal heat diarrhea,
because it coincides with the first estrus cycle post-foaling in the dam.
Causes of foal heat diarrhea are poorly understood, but are thought to be related to a
foal's tendency to start sampling hay and grain and practice coprophagy by 5 to 7 days
of age, with consequent alterations in bacterial flora.
Foals are active and alert, with a normal appetite and vital signs. Clinical signs such as
fever and lethargy, hematochezia or melena, and laboratory findings such as
neutropenia are not routinely observed.
✔✔An outbreak of diarrheal disease of piglets has occurred which affected the
healthiest animals in the herd, 1-2 weeks after weaning.
Some affected piglets had no signs except peracute death. Other affected piglets exhibit
diarrhea, ataxia, paralysis, and recumbency. What condition is at the top of the
differential diagnosis list?
A - Clostridium perfringens type C enteritis
B - Hemagglutinating encephalomyelitis virus (HEV)
C - Porcine proliferative enteritis
D - Epidemic transmissible gastroenteritis (TGE)
E - Edema disease - ✔✔E
, Edema disease is caused by Shiga toxin-producing E. coli (STEC). Look for severe
acute illness ranging from peracute death with no signs to CNS involvement with ataxia,
paralysis, and recumbency in healthiest pigs 1-2 weeks after weaning.
Hemagglutinating encephalomyelitis virus (HEV), is almost exclusive to piglets less than
4 weeks old. Two clinical presentations: Vomiting and wasting disease (VWD) and
encephalitic.
Clostridium perfringens type C enteritis ,also called enterotoxemia in other animals, is
characterized by a HEMORRHAGIC diarrhea in 1-3 day old piglets.
Porcine proliferative enteritis is principally a diarrheal disease of growing finishing (40-
to 80-lb) pigs and young breeding pigs.
Epidemic transmissible gastroenteritis (TGE) in non-immune pig herds characterized by
HIGH MORBIDITY and HIGH MORTALITY in piglets less than 1 week old.
✔✔Many turkeys on a poultry farm develop whitish "wart-like" nodules and scabs on the
comb, wattles, feet, and vent. Which management intervention would help prevent
spread of the disease?
A - Add antibiotics to the drinking water
B - Mosquito control
C - Raise the room temperature 5 degrees
D - Immediate removal of fecal waste
E - Thoroughly disinfect pens and equipment
F - Tick control - ✔✔B
The condition described here is is the dry form of avian (fowl) pox. This is a relatively
slow spreading disease that can be spread by contact or by mosquitoes that may harbor
infective virus for greater than a month.
In the dry form of the disease, the main sign is raised, whitish wart-like lesions on
unfeathered areas (head, legs, vent, etc.). The lesions heal in about 2 weeks.
Unthriftiness, decreased egg production and retarded growth may be seen. Mortality is
low with this form of the disease. The wet form mainly involves the oral cavity and upper
respiratory tract. Lesions are diphtheritic and can ulcerate or erode mucous
membranes. Marked respiratory involvement can lead to mortality
A diagnosis is usually based on flock history and presence of these lesions. This is a
pox virus and there is no specific effective treatment but there is a vaccine. Disease
control is best accomplished by preventive vaccine as sanitation alone will not prevent
spread of disease. Several vaccines are available and a single application results in
permanent immunity.
ANSWERS SET A+
✔✔A 2-year old heifer is presented who died the night before. She was stunted
compared to her herdmates, and had a 3-week history of poor appetite, unthriftiness,
diarrhea. Necropsy reveals that the abomasum is edematous and covered in small
umbilicated nodules 1-2 mm in diameter (cobblestone or "Moroccan leather"
appearance).
Several other younger cows in this Spring-calving herd look unthrifty and have diarrhea
too. What is the plan of action?
A - Cull the sick cows, Keep horses off same pasture 3 months
B - Deworm cows post-calving, calves by midsummer, all stock in fall
C - Treat affected heifers with Albendazole
D - Treat affected heifers with Ivermectin, repeat in 6 months
E - Treat herd with Amprolium, repeat q 5 weeks - ✔✔B
Treatment includes deworming cows post-calving, calves by midsummer, all stock in
fall.
An abomasum with a cobblestone or "Moroccan leather" appearance is pathognomonic
for Ostertagia , one of the three stomach worms of cattle. These worms remain dormant
in the gastric glands of the abomasum, emerging in the spring. Rx is based on regular
deworming of whole herd (2-4 times/year). Ivermectin or high dose
Albendazole/Fenbendazole, given repeatedly can help treat the dormant ("hypobiotic")
Ostertagia in the gastric glands.
Amprolium is your treatment of choices for calves and cows with Coccidiosis.
✔✔A practice is using an FeLV test with a sensitivity of 90% and a specificity of 95%.
Assuming the prevalence of feline leukemia in the area is 5%, what is the predictive
value positive (PVP) of the test?
,A - 45%
B - 48%
C - 55%
D - 88%
E - 90% - ✔✔It is 48%. The trick with this kind of question is to pick an imaginary
number of animals that you test, like 1000, and fill out your 2x2 table from there. Follow
the links to see diagrams step by step.
If prev is 5% then there must be 50/1000 cats with FeLV and 950 cats that are disease-
free.
A 90% sensitive test will correctly call 45/50 positive (box "a"), and IN-correctly call 5/50
negative, (box "c": these are the false negs).
If 50/1000 animals are infected, then 950/1000 are disease-free. Your 95% specific test
will correctly call 902/950 disease-free (box "d": 0.95 X 950=902) and IN-correctly call
48/950 positive, (box "b": these are the false pos).
Now your a,b,c,d boxes are all filled, it is easy to calculate PVP
=a/(a+b)=45/(45+48)=48%
✔✔A 4 year old mare has bilateral swelling and drainage of the mandibular lymph
nodes. Rectal temperature is 101.8F (38.8 C). Which of the following is the most
appropriate plan for this horse?
A - Administer corticosteroids
B - Culture the discharge for bacteria
C - Inform the state veterinarian
D - Administer penicillin - ✔✔B
The correct answer is to culture the discharge for bacteria. The most likely diagnosis for
this horse is equine strangles. Strangles most commonly affects younger horses (<5
years of age), but can cause disease in any age horse. The etiologic agent of this
disease is Streptococcus equi subsp. equi. The diagnostic test of choice to confirm this
is bacterial culture. While awaiting culture results, the horse should be separated from
any other horses, as strangles is highly contagious to other horses. Antibiotic therapy is
controversial and thought to lengthen the course of disease rather than shorten it when
given at this stage; also, it may possibly interfere with the natural immunity acquired
from natural infection. This is not a reportable disease.
✔✔When performing a subtotal colectomy on a feline patient, what blood vessel limits
the amount of colon that you are able to remove?
A - Pudendal artery
B - Caudal mesenteric artery
,C - Left colic artery
D - Ileocolic artery - ✔✔D
The correct answer is ileocolic artery. The site for colonic resection is limited by tension
on the ileocolic artery when trying to suture your new end of colon to the rectum.
Sometimes the tension is too great and instead of a colocolic anastomosis, an ileocolic
anastomosis must be performed. Essentially you are trying to connect a section of
ascending colon to the rectum. Now that can be pretty far! Performing an ileocolic
anastomosis is not ideal because you eliminate the ileocecal valve, and that may
predispose the animal to bacterial overgrowth. The caudal mesenteric artery gives
branches to the rectum and descending colon. The left colic artery also feeds the
descending colon. The pudendal artery supplies the external genitalia. The ileocolic
artery provides blood supply to the ascending and transverse colon.
✔✔Foal heat diarrhea is typically associated with which choice?
A - Hemorrhagic enteritis
B - Neutropenia and fever
C - Decreased suckling
D - Alterations in diet
E - Warm and humid weather - ✔✔D
Mild, self-limiting diarrhea in a foal 7-14 days of age is called foal heat diarrhea,
because it coincides with the first estrus cycle post-foaling in the dam.
Causes of foal heat diarrhea are poorly understood, but are thought to be related to a
foal's tendency to start sampling hay and grain and practice coprophagy by 5 to 7 days
of age, with consequent alterations in bacterial flora.
Foals are active and alert, with a normal appetite and vital signs. Clinical signs such as
fever and lethargy, hematochezia or melena, and laboratory findings such as
neutropenia are not routinely observed.
✔✔An outbreak of diarrheal disease of piglets has occurred which affected the
healthiest animals in the herd, 1-2 weeks after weaning.
Some affected piglets had no signs except peracute death. Other affected piglets exhibit
diarrhea, ataxia, paralysis, and recumbency. What condition is at the top of the
differential diagnosis list?
A - Clostridium perfringens type C enteritis
B - Hemagglutinating encephalomyelitis virus (HEV)
C - Porcine proliferative enteritis
D - Epidemic transmissible gastroenteritis (TGE)
E - Edema disease - ✔✔E
, Edema disease is caused by Shiga toxin-producing E. coli (STEC). Look for severe
acute illness ranging from peracute death with no signs to CNS involvement with ataxia,
paralysis, and recumbency in healthiest pigs 1-2 weeks after weaning.
Hemagglutinating encephalomyelitis virus (HEV), is almost exclusive to piglets less than
4 weeks old. Two clinical presentations: Vomiting and wasting disease (VWD) and
encephalitic.
Clostridium perfringens type C enteritis ,also called enterotoxemia in other animals, is
characterized by a HEMORRHAGIC diarrhea in 1-3 day old piglets.
Porcine proliferative enteritis is principally a diarrheal disease of growing finishing (40-
to 80-lb) pigs and young breeding pigs.
Epidemic transmissible gastroenteritis (TGE) in non-immune pig herds characterized by
HIGH MORBIDITY and HIGH MORTALITY in piglets less than 1 week old.
✔✔Many turkeys on a poultry farm develop whitish "wart-like" nodules and scabs on the
comb, wattles, feet, and vent. Which management intervention would help prevent
spread of the disease?
A - Add antibiotics to the drinking water
B - Mosquito control
C - Raise the room temperature 5 degrees
D - Immediate removal of fecal waste
E - Thoroughly disinfect pens and equipment
F - Tick control - ✔✔B
The condition described here is is the dry form of avian (fowl) pox. This is a relatively
slow spreading disease that can be spread by contact or by mosquitoes that may harbor
infective virus for greater than a month.
In the dry form of the disease, the main sign is raised, whitish wart-like lesions on
unfeathered areas (head, legs, vent, etc.). The lesions heal in about 2 weeks.
Unthriftiness, decreased egg production and retarded growth may be seen. Mortality is
low with this form of the disease. The wet form mainly involves the oral cavity and upper
respiratory tract. Lesions are diphtheritic and can ulcerate or erode mucous
membranes. Marked respiratory involvement can lead to mortality
A diagnosis is usually based on flock history and presence of these lesions. This is a
pox virus and there is no specific effective treatment but there is a vaccine. Disease
control is best accomplished by preventive vaccine as sanitation alone will not prevent
spread of disease. Several vaccines are available and a single application results in
permanent immunity.
