NAVLE END OF COURSE QUESTIONS AND
ANSWERS SET A+
✔✔A 4-year-old Thoroughbred mare is presented with a sudden onset of profuse,
watery diarrhea and marked depression.
The mare has been treated intermittently with phenylbutazone over the last 2 months for
minor lameness and was recently transported to the racetrack by trailer for 9 hours.
On physical exam the horse is dehydrated, with a slow capillary refill time, purplish
mucous membranes, and cold extremities.
No gastric reflux is present. No distention or displacement of bowel is found with rectal
exam, but the rectal wall feels thickened.
T=97.0 F (37.8 C)..[N 99-101.3 F, N=37.2-38.5 C]
HR=92 bpm.............[N 28-40 bpm]
RR=50 brpm............[N 10-14 brpm]
PCV=70%................[N 32-53%]
Total protein 4.0 g/dl .......[N 5.8 - 7.5 g/dl]
The horse dies 3 hours later. On necropsy the walls of the cecum, large colon, and
rectum are edematous and hemorrhagic; intestinal contents are primarily
serosanguinous flu - ✔✔E
This is the clinical picture of colitis X, a lethal diarrheal disease of horses with an acute
to peracute-onset.
The specific cause is unknown, but infectious and toxic etiologies are most likely.
Anaphylaxis also produces similar intestinal lesions. Look for signs of shock, peracute
severe diarrhea and a packed red cell volume (PCV) above 65%, and sudden death.
Some cases may die before diarrhea is seen. The cause is unknown but stress (like
transport) or surgery often precedes disease. This is a diagnosis of exclusion.
, If other potential causes of peracute diarrhea such as Salmonellosis, Potomac horse
fever (PHF), Clostridial enterocolitis, cantharidin toxicity, etc., are ruled out, you are left
with Colitis X.
This is not likely to be NSAID-associated right dorsal colitis due to the distribution of
lesions seen at necropsy and the minimal amount of NSAIDs the horse had received
(and not recently).
✔✔Which one of the following ectoparasites normally spends its entire life cycle on the
chicken, causing feather damage, anemia and irritation?
A - Neocnemidocoptes gallinae
B - Dermanyssus gallinae
C - Northern fowl mite
D - Trombicula alfreddugesi
E - Red chicken mite - ✔✔C
The Northern fowl mite (Ornithonyssus sylviarum) is the only poultry mite that normally
spends its entire life cycle on the host. O. sylviarum is the most important parasite of
caged layers and breeding chickens in the U.S..
Click here to see northern fowl mites on a hen.
MOST chicken mites are nocturnal feeders that are only on the birds at night. They hide
during the day away from the chicken, under manure and in crevices of the chicken
house, where they lay eggs.
✔✔Which of these drugs has the greatest potential for causing acute renal failure in the
horse?
A - Oxytetracycline
B - Xylazine
C - Dexamethasone
D - Neomycin
E - Diphenhydramine - ✔✔D
The correct answer is neomycin. Aminoglycosides are one of the most common causes
of renal tubular nephrosis and acute renal failure. Of the aminoglycosides, neomycin is
probably the most nephrotoxic, followed by gentamicin, amikacin, and streptomycin.
The other big class of nephrotoxic drugs is non-steroidal anti-inflammatory drugs.
✔✔A 4 month old calf from a small beef herd presents with a fracture of the right
metatarsus. He was normal last night. The owner found the calf this morning after
rounding up the herd for deworming. This is the 5th calf this season with fractured
bones. One had a vertebral fracture, two calves had humeral fractures, and one other
ANSWERS SET A+
✔✔A 4-year-old Thoroughbred mare is presented with a sudden onset of profuse,
watery diarrhea and marked depression.
The mare has been treated intermittently with phenylbutazone over the last 2 months for
minor lameness and was recently transported to the racetrack by trailer for 9 hours.
On physical exam the horse is dehydrated, with a slow capillary refill time, purplish
mucous membranes, and cold extremities.
No gastric reflux is present. No distention or displacement of bowel is found with rectal
exam, but the rectal wall feels thickened.
T=97.0 F (37.8 C)..[N 99-101.3 F, N=37.2-38.5 C]
HR=92 bpm.............[N 28-40 bpm]
RR=50 brpm............[N 10-14 brpm]
PCV=70%................[N 32-53%]
Total protein 4.0 g/dl .......[N 5.8 - 7.5 g/dl]
The horse dies 3 hours later. On necropsy the walls of the cecum, large colon, and
rectum are edematous and hemorrhagic; intestinal contents are primarily
serosanguinous flu - ✔✔E
This is the clinical picture of colitis X, a lethal diarrheal disease of horses with an acute
to peracute-onset.
The specific cause is unknown, but infectious and toxic etiologies are most likely.
Anaphylaxis also produces similar intestinal lesions. Look for signs of shock, peracute
severe diarrhea and a packed red cell volume (PCV) above 65%, and sudden death.
Some cases may die before diarrhea is seen. The cause is unknown but stress (like
transport) or surgery often precedes disease. This is a diagnosis of exclusion.
, If other potential causes of peracute diarrhea such as Salmonellosis, Potomac horse
fever (PHF), Clostridial enterocolitis, cantharidin toxicity, etc., are ruled out, you are left
with Colitis X.
This is not likely to be NSAID-associated right dorsal colitis due to the distribution of
lesions seen at necropsy and the minimal amount of NSAIDs the horse had received
(and not recently).
✔✔Which one of the following ectoparasites normally spends its entire life cycle on the
chicken, causing feather damage, anemia and irritation?
A - Neocnemidocoptes gallinae
B - Dermanyssus gallinae
C - Northern fowl mite
D - Trombicula alfreddugesi
E - Red chicken mite - ✔✔C
The Northern fowl mite (Ornithonyssus sylviarum) is the only poultry mite that normally
spends its entire life cycle on the host. O. sylviarum is the most important parasite of
caged layers and breeding chickens in the U.S..
Click here to see northern fowl mites on a hen.
MOST chicken mites are nocturnal feeders that are only on the birds at night. They hide
during the day away from the chicken, under manure and in crevices of the chicken
house, where they lay eggs.
✔✔Which of these drugs has the greatest potential for causing acute renal failure in the
horse?
A - Oxytetracycline
B - Xylazine
C - Dexamethasone
D - Neomycin
E - Diphenhydramine - ✔✔D
The correct answer is neomycin. Aminoglycosides are one of the most common causes
of renal tubular nephrosis and acute renal failure. Of the aminoglycosides, neomycin is
probably the most nephrotoxic, followed by gentamicin, amikacin, and streptomycin.
The other big class of nephrotoxic drugs is non-steroidal anti-inflammatory drugs.
✔✔A 4 month old calf from a small beef herd presents with a fracture of the right
metatarsus. He was normal last night. The owner found the calf this morning after
rounding up the herd for deworming. This is the 5th calf this season with fractured
bones. One had a vertebral fracture, two calves had humeral fractures, and one other
