Parturition Flashcards
1
Q
Stages of Parturition
A
Stage of preparation
First stage
Second stage
Third stage
2
Q
Stage of preparation
A
- Production of relaxin
○ Causes relaxation of soft tissues of reproductive tract and perineum - Fetal maturation
3
Q
First stage parturition
A
- Stimulates increase in PG and decrease in progesterone from CL or placenta
- Increase in relaxin allowing cervix to dilate
- Results in myometrial excitability and onset of uterine contractions
- Fetus assumes position for expulsion
4
Q
Second Stage Parturition
A
- Uterine contractions push fetus into birth canal
- Abdominal contraction are additive
- Ferguson’s reflex produces additional uterine contractions
- Fetus delivered
5
Q
Third stage parturition
A
- Abdominal contractions largely cease
- Myometrial contraction decrease in amplitude but are more frequent and less regular
- Placenta expelled
6
Q
How does 2nd/3rd stage differ in polytocous species
A
2nd and 3rd stage overlap
Occurs between each fetus delivery
Occurs separately monotocous species
7
Q
Chronology of second stage parturition in different species
A
Second stage is complete when all foetuses have been delivered
○ Mare - 30 minutes
○ Cow - 1 hour
○ Ewe - 1 hour
○ Queen - 2 hours
○ Sow - 3 hours
○ Bitch - 6 hours
2nd stage is longer in polytocous species
8
Q
Dystocia
A
Difficulty in parturition
~5% of parturitions rest in dystocia
* varies according to:
○ Species
○ Breed
○ Age of dam
○ Match of sire to dam
9
Q
Dystocia in cows
A
- Heifers may be bred at an early age
○ Dystocia common - Breed important
○ Holstein have high incidence - Beef sires often used resulting in large calf
○ Feto-maternal disproportion is common
○ Common challenges are establishing if calf is deliverable - Faulty disposition is less common
- Twin pregnancies occur and have 2.5x greater risk
- Fetal monsters not uncommon
- Maternal dystocia is uncommon
○ Include incomplete cervix dilation, and uterine inertia due to hypocalcaemia
