8- Normal parturition Flashcards
What hormone is produced at the stage of preparation during birth?
Relaxin
Foetal cortisol production at parturition has what 3 effects on hormones?
Increase in uterine PGF2a
Reduces progesterone levels by conversion into estradiol (removes block on myometrial contractions)
Increase in relaxin
What are the 3 stages of parturition?
preparatory stage, (onset of contractions) expulsion of fetus, expulsion of placenta
First sign of expulsion of the foetus is occuring
Abdominal contractions
Which contractions come first uterine or abdominal?
Uterine in prep stage (first stage of parturition- generally not seen by owner)
What is the Fergusons reflex?
Pressure within the cervix causes a release of oxytocin > Stimulates myometrial contractions
(pressure caused by foetus pushing against cervix)
What is dystocia?
difficulty giving birth
Name 2 foetal causes of dystocia
Abnormal disposition - presentation, position, posture
Oversize - congenital monsters, foetal pathology
How long is the second stage of parturition in a cow and mare
Mare- 30 mins
Cow- 1 hour
Name 2 maternal causes of dystocia
Expulsive forces - uterine inertia, weak abdominal straining
Size of birth canal - pelvis/dilation
What effect does relaxin have
causes the relaxation and softening of cervix, pelvic ligaments and perineum
Describe what happens during the third stage of parturition
abdominal contractions largely cease
myometrial contractions decrease in amplitude but become more frequent and less regular
placenta expelled
What is primary inertia and which species does it generally affect
where uterine contractions are weak, so foetus not pushed into cervix so abdominal contractions don’t occur
common cause of dystocia in dogs and pigs
T/F duration and degree of effort is usually more in multigravida animals compared to primigravida
False
T/F In the cow twin pregnancies are more likely to cause dystocia
True- 2.5 times more likely to occur
