The answer is Star.
In equine terminology, a star is a small white marking located on the forehead. The other options refer to different markings:
- Stripe - a narrow white line running down the face (from forehead toward the nose)
- Snip - a small white marking on the muzzle/nostril area
- Blaze - a wide white marking running the full length of the faceThe answer is Oral bioavailability is often unpredictable.
Here's why each option is correct or incorrect:
- "All drugs are well absorbed orally" - False. Many drugs have poor or variable oral absorption in horses. The large hindgut, rapid gastrointestinal transit, and first-pass metabolism all affect absorption significantly.
- "Oral bioavailability is often unpredictable" ✓ - Correct. Horses have a unique GI tract (large fermentation vat in the hindgut, variable gastric pH, gut motility) that makes oral bioavailability highly variable and species-specific. Feed status, gut motility, and the drug's physicochemical properties all contribute to this unpredictability.
- "Oral administration is never recommended" - False. Many drugs ARE given orally to horses (e.g., phenylbutazone, omeprazole, trimethoprim-sulfa). It is a common route.
- "Horses absorb drugs exactly like dogs" - False. Horses are hindgut fermenters with fundamentally different GI physiology from dogs (monogastric carnivores), leading to very different pharmacokinetic profiles for many drugs.The answer is Flunixin meglumine.
Flunixin meglumine (Banamine) should NOT be given intramuscularly (IM) in horses due to a well-documented risk of clostridial myositis (a severe, often fatal muscle infection caused by Clostridium spp.). This is a black-box warning in equine medicine.
Why the others are incorrect:
- Ketoprofen - given IV in horses; IM use is not specifically associated with clostridial myositis in the same way
- Meloxicam - typically given orally or IV in horses; not the classic culprit for this warning
- Aspirin - given orally in horses; not administered IM
The key teaching point: Flunixin meglumine is labeled for IV use only in horses. IM injection creates an ideal anaerobic environment in muscle tissue that allows Clostridium spores (present on skin/in the environment) to proliferate, causing gas gangrene/myositis that can be rapidly fatal. Horse owners must be specifically counseled against giving "Banamine" shots intramuscularly at home.The answer is 8.
Horses have 8 major blood group systems, designated by letters:
- A, C, D, K, P, Q, U, T
Key points about equine blood groups:
- Within these 8 systems, there are numerous blood factors (antigens), making equine blood typing quite complex
- The most clinically significant systems are A and Q, as these are most commonly involved in neonatal isoerythrolysis (NI) - a potentially fatal hemolytic disease in foals
- Unlike humans (ABO system), horses do not have naturally occurring alloantibodies, so first-time transfusions are generally safer, but sensitization can occur with subsequent transfusions
- Blood typing and crossmatching are recommended before equine blood transfusions, especially in mares that have had prior pregnancies or transfusionsQuestion 7: Ultrasonography
Ultrasound is the gold standard for diagnosing tendon injuries in horses. It allows real-time visualization of tendon fiber architecture, core lesions, cross-sectional area, and echogenicity. It is used to diagnose superficial digital flexor tendon (SDFT) injuries, deep digital flexor tendon (DDFT) injuries, and suspensory ligament injuries - the most common soft tissue injuries in sport horses. Radiography shows bone, not soft tissue. CT is useful but not practical for standing horses in the field. ECG is for cardiac evaluation.
Question 8: Aged horses with missing incisors
A "Gummer" is the term used for an old horse that has lost its incisor teeth, leaving only bare gums visible. As horses age, their teeth erupt progressively and eventually fall out or wear down completely. A very old horse with no remaining incisors is colloquially called a "gummer." This term is relevant in equine dentistry and aging - horses are typically aged by their teeth, so a gummer is by definition very old (usually 20+ years). The other options (young foals, mature stallions, pregnant mares) have no connection to this term.The answer is Strangles.
The classic triad described - fever + purulent nasal discharge + enlarged submandibular lymph nodes - is the textbook presentation of Strangles, caused by Streptococcus equi subsp. equi.
Why each option fits or doesn't:
-
Strangles ✓ - The hallmark signs are high fever, thick mucopurulent nasal discharge, and marked enlargement/abscessation of the submandibular and retropharyngeal lymph nodes. The abscesses can become so large they compress the airway ("strangles" the horse). Highly contagious.
-
Equine influenza - Causes fever and nasal discharge, but the discharge is initially serous (watery), and lymph node enlargement is not a prominent feature. It's primarily a respiratory virus causing cough and clear discharge.
-
Equine viral arteritis (EVA) - Causes fever, nasal discharge, limb edema, and conjunctivitis, but not characteristically enlarged submandibular lymph nodes.
-
Potomac horse fever (Neorickettsia risticii) - Causes fever, diarrhea, and laminitis. Nasal discharge and lymphadenopathy are not typical features.
The enlarged submandibular lymph nodes is the key discriminating clue pointing directly to Strangles.Question 10: Jugular vein
The jugular vein is the most important venous access site in horses before anesthesia induction. It is the primary IV access route in equine medicine because:
- It is large, superficial, and easily accessible in the jugular groove of the neck
- It allows rapid delivery of large volumes of induction agents (ketamine, guaifenesin, etc.)
- IV catheters (14-16 gauge) are routinely placed in the jugular vein for anesthetic induction and maintenance drug delivery
- It is the standard site for all major equine procedures requiring IV access
The cephalic vein is small and used mainly in foals. The lateral thoracic and saphenous veins are rarely used for primary IV access.
Question 11: 8-16 breaths/minute
The normal resting respiratory rate of an adult horse is 8-16 breaths/minute (commonly cited as 8-12 or up to 16 breaths/min at rest).
Quick reference for equine vital signs:
- Heart rate: 28-44 beats/minute
- Respiratory rate: 8-16 breaths/minute
- Temperature: 37.2-38.3°C (99-101°F)
- Gut sounds: present in all 4 quadrants
Values above 16 breaths/min at rest suggest respiratory distress, pain, fever, or excitement. The ranges 4-6 (too low), 20-30, and 35-45 are all abnormally high or outside normal equine physiology.Question 12: Thoroughbred
The Thoroughbred is recognized as the fastest horse breed in the world over distance. Top speed recorded is around 70 km/h (43 mph). Thoroughbreds dominate flat racing worldwide and were specifically bred for speed over centuries.
- Quarter Horse - actually the fastest over a quarter mile (short sprint, up to ~88 km/h), so this is a nuanced point. If the question refers to sustained speed/racing, Thoroughbred is the standard answer. Quarter Horses win at 400m but cannot sustain that pace.
- Arabian - known for endurance, not top speed
- Clydesdale - a heavy draft breed, bred for pulling, not speed
For this quiz context, Thoroughbred is the expected answer as the world's premier racing breed.
Question 13: Two beat gait
The trot is a two-beat diagonal gait. In the trot:
- Diagonal pairs of legs move together simultaneously: left front + right hind move as one beat, then right front + left hind as the second beat
- There is a brief moment of suspension between the two beats
Quick reference for equine gaits:
| Gait | Beats | Pattern |
|---|---|---|
| Walk | 4 | Lateral sequence |
| Trot | 2 | Diagonal pairs |
| Canter/Lope | 3 | Three distinct footfalls |
| Gallop | 4 | All four feet separate |
The trot is the classic "posting" gait used in dressage, eventing, and harness racing (where it is highly regulated).The answer is Stocking.
White leg markings in horses are named based on how high they extend up the leg:
| Marking | Extent |
|---|---|
| Coronet | Just around the coronet band (top of hoof) |
| Pastern | Covers the pastern region |
| Sock | Extends up to the fetlock/cannon area (below the knee) |
| Stocking | Extends above the knee or hock |
So the progression goes from bottom to top: Coronet → Pastern → Sock → Stocking. A stocking is the most extensive white leg marking, covering the lower leg all the way from the hoof up past the knee (carpus) on the front leg or hock (tarsus) on the hind leg. These markings are used in official horse identification records.
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