2. Footpads, hooves, horns, antlers

Question 1

What does the number of digital pads correspond to?

Answer 1

number of digits

Question 2

The digital footpads are homologous with what?

Answer 2

• BULB of ruminates + pigs
  -FROG of horses

Question 3

what is the structure of footpads?

Answer 3

• Thick subcutis with adipose tissue, portioned by collagen + elastic fibres
• ligaments anchor pad to the skeleton
• thickly cornified epidermis
• have eccrine sweat glands
• has stratum lucid layer

Question 4

what is the functions of footpads?

Answer 4

• protection
• grip
• shock absorber

Question 5

what are the similar components of nails/claws/ hooves and there functions

Answer 5

similar components:
- wall
- sole
- footpad

functions:

• protects distal digit
• tool for scratching/digging etc
• defence/hunting
• blood circulation

Question 6

what is known as the horn in nails/claws/hooves?

Answer 6

highly keratinised epidermis

Question 7

where is the coronet found in horses?

Answer 7

junction between skin epidermis + hoof

Question 8

what does periods of disturbed growth result in?

Answer 8

transverse ridges

Question 9

nails/hooves/ claws are epidermal structure, how are they anchored to the underlying dermis?

Answer 9

interdigitations of laminae

Question 10

in claws what is dermis also known as?

Answer 10

the ‘quick’

Question 11

what is the dermis (quick) closely adhered to?

Answer 11

periosteum of distal phalanx

Question 12

what keeps cats claws retracted?

Answer 12

elastic dorsal ligaments

Question 13

what are the special considerations of horse hooves we should know?

Answer 13

• Digit loss - only digit III is weight-bearing
• Elongation of distal limb segments
• Muscle mass concentrated proximally
• Motion restricted to protraction and retraction
• All ‘cursorial’ adaptations for running
• no foot no horse
• poor venous return

Question 14

what is the dermis called in the hoof?

Answer 14

corium

Question 15

what are the 5 parts of the dermis in the hoof?

Answer 15

• perioplic
• coronary
• lamellar
• solar
• frog

Question 16

what is the subcutis of a horse?

Answer 16

coronary cushion + digital cushion

Question 17

what is the 3 layers of the hoof epidermis?

Answer 17

• stratum externum
• stratum medium
• stratum internum

Question 18

in the 3 epidermis hoof layers, which are pigmented and which are not?

Answer 18

pigments = stratum medium
unpigmented = stratum externum and internum

Question 19

what is the white line of a hoof?

Answer 19

junction of the soft sole of the foot and hard hoof wall

Question 20

what is the white line made of?

Answer 20

the worn end of the epidermal laminae + the interlamellar horn from terminal papillae

Question 21

what does the white line indicate the silhouette of?

Answer 21

distal phalanx/pedal bone

Question 22

How does venous return in a horse hoof work?

Answer 22

• compression of the frog (footpad) pushes the digital cushion outwards and squashed the hoof cartilage
• venous plexus in the cartilages are squashed, squeezing the blood out into digital veins
• digital veins have valves so blood can’t flow backwards

Question 23

what family are antlers seen in?

Answer 23

cervids

Question 24

what are the similarities of horns and antlers?

Answer 24

• Initially formed from a bony core covered by integument
• Located on the frontal bone
• Paired and usually symmetrical
• Present or larger in males
• But in some species and breeds, both sexes can have horns e.g. cattle, reindeer, goats, some sheep
• Weapons, social signal

Question 25

how do antlers grow?

Answer 25

• Antlers grow from an attachment on the skull (‘pedicle’)
• When growing, antlers are covered in well-vascularised skin (“in velvet”)
• When finished growing, blood supply to skin cuts off and velvet is shed (“in tatters”)

Question 26

how do horns grow?

Answer 26

Horn bud starts out in the subcutis and later fuses to skull

Question 27

are antlers branched?

Answer 27

yes

Question 28

do antlers shed?

Answer 28

yes

Question 29

why is it better do disbud a calf?

Answer 29

• Horn bud starts out ‘floating’ in integument
• Later attaches to frontal bone
• At 6 months, frontal sinus starts extending into horn’s bony core

Question 30

what is the risk of a horn fracture or dehorning older animals?

Answer 30

sinus infection