1. PARTURITION AND POSTPARTUM RECOVERY Flashcards
What are the 3 parturition stages?
- softening and dilation of the cervix –> complete dilation of the cervix –> fetus enters the cervix
- Complete dilation of the cervix –> fetus expelled
- Expulsion of the placenta
What is the normal birth position?
rests on it thorax/abdomen with the head facing backwards (towards the cervix). Nose is resting between the forefeet
forefeet against cervix
In monotocous species, what is the first sign of parturition?
Rotation of fetus
As parturition approaches what happens to the mammary glands?
They grow rapidly and glands enlarge as they fill with milk. As oxytocin is released during labour, milk let down will occur.
What are other changes that occur during the birthing process?
- relaxin synergise with oestrogen, which causes the expansion of the pelvis and birth canal
- The vulva becomes soft and swollen
- mucus is excreted from the vulva
- nesting instincts kick in
During late gestation there are high levels of
progresterone, relaxin, oestrogen.
48 hrs before parturition, there are rapid changes in the maternal hormones which include…….
decrease in progesterone, increase in relaxin, oestrogen, oxytocin, PGF2alpha
What triggers the rapid changes in the maternal hormones
Foetal cortisol
Give the hormonal changes that occur due to incease in foetal cortisol. for cows does and sows.
- This foetal cortisol causes the release of enzymes,
- then P4 gets converted to E2 by these enzymes
- this causes an increase in placental E2 and a decrease in P4
- causes an increase in endometrial PGF2alpha
- CL regresses
- P4 decreases
- increase in myometrium contractions
what increases the release of PGF2alpha
oxytocin
When is oxytocin at its highest conc.
expulsion of the fetus
What are the stress responses that have a positive regulatory influence on milk synthesis
maternal cortisol and prolactin
what are the 2 main physiological events of parturition
- dilation of the cervix
- uterine contractions
What causes initial dilation of the cervix?
relaxin as it synergises with the increase levels of oestrogen
What causes uterine contractions?
- Reduced P4 reduces contraction inhibition
- Low P4 along with rising oestrogen up regulates uterine receptors for E2 and oxytocin in the myometrium
- initial contractions are due to the PGF2a from the endometrium by increasing oestrogen
- when the fetus is in the cervix, the sensory nerves are stimulated and oxytocin is released which initiates stronger uterine contractions
Define anoxia
lower oxygen supply to the fetus
What are the advantages of induced parturition?
- group parturition facilitate closer observation
- more offspring with the same age, size
- shorter gestation and general interval
- set precise time for parturition
- allows for extra time to resume breeding
- medical reasons like pregnancy toxaemia
What are the disadvantages of induced parturition?
- endometriosis
- delayed onset of puberty
- reduced first cycle pregnancy rate
- cattle have a high incidence of retained placenta
- treatments only effective close to term , must know exact breeding rate
How is corticosteroids used to induce parturition?
- corticosteroids include dexamethasone and flumethasone
- with a single injection 2 weeks prior to normal parturition in cattle
- parturitions happens 24 to 72 hrs later
- works on placenta effectiveness, depends on placental penetration
How is prostaglandins used to induce parturition?
- injected near the calving date
- parturition happens 24 to 72 hrs later
- causes a cl degeneration
- if you inject cattle before 200 days or after 260 days the fetus will be aborted
Which 2 substances can be injected into animals to induce parturition?
- corticosteroids
- prostaglandins
What is dystocia?
Prolonged and difficult parturition
What causes dystocia?
- oversized fetus
- twin pregnancies
- abnormal position
- cattle has a small pelvic diameter
- heifer is bred before the ideal weight
- dystocia is more common in male animals
How long does the 3 parturition stages tage in a cow?
1= 2-6 hrs 2= 30-60 min 3= 6-12 hrs