Species adaptation: horse

Question 1

what 3 horses are all racehorses derived from and what are the consequenes

Answer 1

• byerly turk
• darley arabian
• godolphin arabian
  results in some prevalent genetic conditions that would not have been known about at the time.

Question 2

what factors enhance stride length in the horse

Answer 2

• mediolaterally flattened thorax with scapula position laterally
• scapula and shoulder joint are free to move (20-30 cm)
• ulna becomes vestigial (olecranon remains functional to increase lever action of triceps m.)
• elongation of distal bones particularily in the metacarpus/tarsus and digit

Question 3

what factors enhance stride rate in the horse

Answer 3

• concentration of musculature proximally
• reduction to a single digit (elongation of the lightest segments of the limb)
• brachium is relatively short and highly muscular

Question 4

what are features of the thoracic limb in the horse

Answer 4

• carry more static bodyweight (minimize vertical energy so hindlimbs can provide horizontal energy)
• shorter and striaghter than the hindlimb (no bone articulation to the skeleton)
• broader and more rounded hoof for absorption of weight
• energy storage in the tendons

Question 5

what are features of the hindlimb in the horse

Answer 5

• provide forward impulstion of the horse
• direct bone articulations to the pelvis and sacral spine
• reciprocal apparatus allows simultaenus extension of the hip, stifle and hock
• narrower and more pointed hoof

Question 6

what 3 mechanisms contribute to the equine stay apparatus

Answer 6

• stifle locking mechanism
• reciprocal apparatus
• suspensory apparatus