Gestation & Parturition

Question 1

Average gestation length

Answer 1

330-350 days

Question 2

Range of gestation

Answer 2

315-370 days

Question 3

Factors affecting gestation length

Answer 3

• Ponies have shorter than horses
• individual horse’s record
• colt’s 2-3 days longer than fillies
• mares with low BCS = longer gestation
• winter/early spring = longer
• late spring/summer = shorter
• late summer/early fall = even shorter
• foal at optimal time for survival
• tall fescue exposure = prolonged gestation

Question 4

Parts of the placenta

Answer 4

• Chorioallantois
• Amnion
• Umbillical cord
• Urachus

Question 5

Choriallantois

Answer 5

• Chorion: closest/attached to uterus (important for nutrition)
• Allantois: attached to chorion, lines allantoic cavity, whitish
• Allantoic cavity: fluid filled, containing waste from fetal metabolism

Question 6

Amnion

Answer 6

Surrounds fetus, forms amniotic cavity, separates foal from waste

Question 7

Umbilical cord

Answer 7

Attaches foal to chorioallantois; supplies nutrients and oxygen; will eventually break about 2 inches from body wall

Question 8

Urachus

Answer 8

Drains waste into allantoic cavity

Question 9

1-3 weeks away from parturition

Answer 9

• Udder development

- Abdomen drops down and back

Question 10

Days/hours before parturition

Answer 10

• udder development: teats full, wax, drip milk (don’t want)
• relaxed muscles around pelvis and tail head
• enlarged vulva

Question 11

Parturition

Answer 11

• usually occurs at night
• usually lying down
• usually when dark and quiet

Question 12

3 stages of labor

Answer 12

1. Positioning of foal in birth canal
2. Delivery
3. Expulsion of placenta

Question 13

Positioning of foal in birth canal

• duration
• signs
• interventions
• end of stage

Answer 13

• usually 30 minutes - 3 hours
• signs: restless, quit eating, gets up and down, sweating, pawing, nipping at stomach (colic symptoms)
• interventions: call farm manager, make sure environment is clean, wrap tail, remove objects from stall (buckets)
• ends when chorioallantois breaks (water breaks)

Question 14

Delivery

Answer 14

• usually less than 40 minutes
• position of foal
• unattachment of umbilical cord

Question 15

Expulsion of placenta

Answer 15

• 30 minutes to 3 hour
• > 3 hour, retained placenta
• tie up placenta to keep out of way
• once placenta is out, check it
• make sure it is complete, check color and consistency, weigh it

Question 16

Position of foal during delivery

Answer 16

1. whitish membrane appears at vulva (amnion)
2. front feet offset/soles towards mare’s hocks
3. muzzle on knees “diving position”
4. muzzle free from anion
5. shoulders (hardest point), staggered position
6. hips then back feet