Parturition Flashcards
what are the signs of approching parturition
development of mammary gland
relaxation of muscles around tail head and vulva
mucus discharge from breakdown of cervical seal
anorexia
isolation
restlessness
waxing, drying teat secretion in mare
placenta showing and cervical dilation
what are the factors that influence length of gestation
species and breed
sex of the fetus
# of fetuses
genetic influence
age of dam
season of birth
how does species and breed affect length of gestation
beef- 283
dairy- 280
brown swiss- 288-290
sheep- 147
swine- 114
equine- 340 draft/ponies-345
how does sex of the fetus affect length of gestation
horses and cattle male fetus results in 1.5 days longer
how does # of fetuses present affect gestation length
cattle twins 5.5 days shorter
equine twins 10 days shorter
sheep triplets or quads 1-2 shorter
swine no difference
how does genetic influence affect gestational legth
recessive genes that prevents delivery at normal time
calves have to be taken via cesarean
how does age of dam affect gestational length
heifers shorter than cows
how does season of birth affect gestational length
mares with extended photoperiod (70 days) in last trimester of pregnancy have a shorter gestation length- 10 days
what are the 3 stages of parturition
1- dilation of the cervix
2- delivery of the fetus
3- expulsion of the placenta
how does fetus present at time of delivery
fetus is carried on side or back
the fetus rotates at time of parturition
what is circadian rhythm
biological event associated with time
86% foal between 7 pm- 7 am
cattle have an even distribution throughout the day
sheep lambs born during the day than at night
what is one way that dystocia will happen in regard to maternal
maternal abnormalities
small pelvic size
tumors in repro
twisted uterus
uterine inertia
failure of cervix to dilate
what is one way that dystocia will happen in regard to fetal
excessive fetal size in relation to dam pelvic
abnormalities of presentation (breech)
twins
stiff fetal joints
for dystocia when should assistance be provided
calving hasn’t occurred within 2 hours of showing membranes
dam stops her efforts
head is visible with blue tongue
for dystocia what are the steps to take when assisting
scrub up
check cervical dilation
check to see if fetus is alive
check pelvic size/area
check position of the calf
for dystocia what are abnormal deliveries
hind legs first
breech (butt first)
head turned back
how do you pull a calf
chains- 1 leg/chain. double loop (cannon bone and pastern) pull calf straight out and down
what are some things to remember when helping deliver after dystocia
dont tear the placenta as it provides lubrication
check for twins or triplets (depends on species)
dystocia problems in all species decreases colostrum absorption
what are some factors associated with retained placentas in farm animals
multiple births
short gestations
induced parturition
selenium deficiency
vitamin A deficiency
how to treat retained placentas
mares- oxytocin
cows- uterine boluses and tetracycline packets
what are 3 hormones administered for retained placentas
PGF2alphs- 2 hours after birth can reduce incidence
oxytocin- sometimes work
GnRH- given 8-14 days after calving in cows that experineced placental retention does reduce the days open but can cause cystic follicles
how does the fetus initiate parturition
space limitations in the uterus cause the release of cortisol from the fetus
cortisol release from the fetus initiates 2 major events- removal of progesterone block from myometrium and switch to estrogen production stimulates repro tract secretions
how does cortisol remove progesterone block from myometrium
cortisol promotes synthesis of enzymes that convert progesterone to estrogen
how does progesterone change for parturition
starts to decline 2-3 days before parturition
declines rapidly within hrs of parturition
enzyme like changes in the placenta causes increasing estrogen levels
how does estrogen change for parturition
product of enzymatically converted progesterone
recruits oxytocin receptors
causes thin mucus-like secretion for lubrication
what does oxytocin do for parturition
levels increase at time of delivery to cause uterine contractions
what does PGF2alpha do for parturition
released 24 hours before rapid drop in progesterone
maximal release at onset of labor
stimulates release of relaxin by the corpus luteum to relax the birth canal
