Horses II Flashcards
At what age does Galvayne’s groove begin to appear in the horse?
- 5 years
- 15 years
- 9 years
- 6 months
Answer: 9 years
Explanation
The correct answer is 9 years. This is useful for the purposes of aging horses. It is a longitudinal groove noted on 13. 11 erupts at 2.5 years, 12 erupts at 3.5 years, and 13 at 4.5 years. The canine tooth erupts at 5 years. The cup from 11 disappears at 6 years, 12 at 7 years, and 13 at 8 years. Galvayne’s groove is half way down the tooth at 15 years and then completely down at 20 years of age.
Which of the following fractures in an adult horse has a grave prognosis for return to function?
- P3 (distal phalanx)
- Ulna
- Tibia
- P1 (proximal phalanx)
Answer: Tibia
Explanation
The correct answer is tibia. Fractures of the tibia are usually non-reconstructable comminuted fractures. Due to the lack of soft tissue coverage, these fractures are highly susceptible to infection, which makes them poor candidates for recovery. As long as the articular surface of P3 is not involved, P3 fractures carry a good prognosis. Most P1 fractures are fairly easily repaired with lag screws as long as they are not comminuted. Ulnar fractures are usually treated with bone plates and have a good prognosis, with about 70% of horses returning to function.
A 2-year old Quarter Horse presents for intermittent muscle fasciculation followed by weakness. What condition should you suspect?
- Grass tetany
- Myotonia
- Stringhalt
- Hyperkalemic periodic paralysis
- Tetanus
Answer: Hyperkalemic periodic paralysis
Explanation
The correct answer is hyperkalemic periodic paralysis (HYPP). HYPP is seen in Quarter Horses due to a point mutation in a key part of a skeletal muscle sodium channel subunit. This results in elevation of the resting membrane potential to increase the likelihood of depolarizing. Excess concentrations of potassium can result in failure of the sodium channels to inactivate. Therefore, treatment is directed at decreasing dietary potassium.
***PowerLecture: Musculoskeletal Disorders
Which condition is associated with apical fracture of the proximal sesamoid bones, avulsion fractures of the palmar aspect of the third metacarpal bone, or fractures of the distal third of the small metacarpal bones in horses?
- Suspensory ligament desmitis
- Superficial digital flexor tendonitis
- Sweeney
- Deep digital flexor tendonitis
Answer: Suspensory ligament desmitis
Explanation
The correct answer is suspensory ligament desmitis. The presence of these fractures would indicate ultrasonography as the next diagnostic test to evaluate for suspensory ligament desmitis, since these fractures are present with this condition 25% of the time.
A 9-day old foal is experiencing mild diarrhea. What is the most likely diagnosis?
- Clostridium perfringens
- Lactose intolerance
- Foal heat diarrhea
- Rhodococcus equi
Answer: Foal heat diarrhea
Explanation
The correct answer is foal heat diarrhea. Although any of these answers could be correct, sometimes this is all you have to go on for some exam questions. To answer this question you need to know at what time periods foals get what diarrhea and the severity.
Foal heat diarrhea is mainly seen at the age of 7-14 days and is usually very mild in nature, making this the best answer choice.
Rhodococcus equi will result in diarrhea in foals that are between the ages of 1-4 months; however, remember that this organism primarily causes respiratory disease, so look for that too.
Clostridium perfringens Types A, B, and C will usually result in an acute to peracute diarrhea in foals, leaving most of them dead in 48 hours if treatment is not instituted.
Primary lactose intolerance is rare in foals.
***PowerLecture: Foal Diarrhea
A 9-day old foal is experiencing mild diarrhea. What is the most likely diagnosis?
- Clostridium perfringens
- Lactose intolerance
- Foal heat diarrhea
- Rhodococcus equi
Answer: Foal heat diarrhea
Explanation
The correct answer is foal heat diarrhea. Although any of these answers could be correct, sometimes this is all you have to go on for some exam questions. To answer this question you need to know at what time periods foals get what diarrhea and the severity.
Foal heat diarrhea is mainly seen at the age of 7-14 days and is usually very mild in nature, making this the best answer choice.
Rhodococcus equi will result in diarrhea in foals that are between the ages of 1-4 months; however, remember that this organism primarily causes respiratory disease, so look for that too.
Clostridium perfringens Types A, B, and C will usually result in an acute to peracute diarrhea in foals, leaving most of them dead in 48 hours if treatment is not instituted.
Primary lactose intolerance is rare in foals.
***PowerLecture: Foal Diarrhea
What is the causative agent of Tyzzer’s disease?
- Clostridium botulinum
- Clostridium perfringens
- Clostridium chauvoei
- Clostridium piliforme
- Clostridium difficile
Answer: Closridium piliforme
Explanation
The correct answer is Clostridium piliforme. This is a motile, filamentous, gram negative, spore forming bacterium. Of note, all Clostridia are categorized as gram positive organisms with the exception of Clostridium piliforme, which is gram negative (yes, Microbiology is confusing). Clinical signs associated with Tyzzer’s include depression, anorexia, coma, convulsions, and jaundice. Horses between 6 days and 6 weeks of age are affected; however, most are affected at 1-2 weeks. Affected foals will have elevated liver enzymes, marked hypoglycemia, and acidosis.
