quiz 8 Flashcards
describe the luteal phase
it takes several days for a CL to form and P4 to rise
what occurs when P4 levels fall
inhibin is removed from the surge center
when does the corpus hemorrhagicum present itself
1-3 days after ovulation
what are granulosa and theca cells turned into
large and small luteal cells
describe large luteal cells
undergo hypertrophy, which increases muscle mass 3 fold
describe small luteal cells
undergo hyperplasia, which increases cell production 5-fold
what does the vascularization of the CL cause
steroid synthesis and delivery of hormones
what does insufficient CL functions cause
failure to remain pregnant
where do waves come from
the tonic center
what supports the embryo before the placenta forms
endometrial glands
what is the primary hormone
PGF2a
describe luteolysis in:
normal uterus
total hysterectomy
contralateral hysterectomy
ipsilateral hysterectomy
normal CL lifespan
longer CL lifespan
normal CL lifespan
longer CL lifespan (35+ days)
mares do/do not have a countercurrent exchange
do not
when is PGF not effective in most animals? in swine?
in the first five days
in the first 10 days
what do luteal cells use to react
Ca second messenger
when does P4 increase
when oxytocin is low
define auto-amplification loop
PGF2a induces PGF2a production in the CL
self-sustaining loop
define feedback loop
PGF2a induces oxytocin in the CL, which releases more PGF2a
positive feedback loop
what does luteolysis cause
decreased blood flow
cellular response
immune response
what is the CL lifespan in a human
12-14 days
what are the 5 causes of manipulating estrus
grouping females for parturation
reducing/eliminating estrus detection
needed for artificial insemination
embryo transfer
schedule for male availability (in horses)
what hormones help with time
PGF2a, GnRH, progestins
what hormones help with superovulation
FSH, eCG
when is PGF2a active for most animals? for swine?
on days 5-17
12-15
what are used to increase PGF2a
lutalyse and estrumate
what does GnRH do
induces ovulation if no CL is present
terminates the follicular wave if CL is present
what removes the negative feedback for GnRH
inhibin and estradiol
what increases GnRH
cysterelin, factrel, and fertagyl for cattle
sucromate for horses
define progestins
stimulates a CL to provide progesterone
prevents ovulation
does progestin affect CL
no
when does progestin occur
2-5 days after ovulation, unless horses, which are 7-9 days after
what increases progestins
injection, feed, implant, controlled internal drug release
regumate is used in equine and swine
describe CIDR
used mostly in ruminants
causes vaginitis in horses
what do eCG and FSH cause
superovulation
define ovsynch
developed for cattle
describe ovsynch
GnRH is given to restart the follicular wave
PGF2a is given a week later for luteolysis
2 days later, GnRH is given again and the dominant follicle ovulates
LH will surge afterwards and ovulation occurs
what progestin is used in sheep? when does it work best? when does it work poorly?
CIDR
in season it works alone
out of season must add eCG
how does prostaglandin work in sheep
only when sheep are in season
what type of light do sheep need
decreased day length
what other supplements can sheep be given
melatonin (oral or IM)
how does prostaglandin react in swine
not practical; only effective on days 12-17
how does the progestin altrenogest react in swine
causes ovarian cysts
given orally for 18 days, which costs $5-10/day
how do weaned piglets react in swine
swine have strong anestrus, but only works for sows
how does puberty induction react in pigs
an FSH and LH-like combination
describe prostaglandin in horses
CL is more sensitive and it is only effective in season
describe sucromate in horses
OV induction in 48 hours
describe hGC in horses
OV induction in 36-42 hours
describe the progesin altrenogest in horses
it is effective in season and reduces estrous behavior
what kind of lighting do horses need
16 hours of light/day for 60-90 days
