how long is the sow follicular phase? the luteal phase?
fol=1 week, lut=2weeks
when does the sow ovulate?
end of estrous
what induces luteolysis of the sow?
signs of estrous?
swelling/reddening of vulva, restlessness, mounting b/h, standing heat ("riding test"--sit on sow, see if she stays)
three important things to know about establishment of preg in the sow
(1) mvt/spacing out of blastocysts by day 10 is essential (2) minimum 2 blastocysts per uterus horn (3) blastocysts produce estrogen after day 12--> causes PGF 2alpha to be secreted into uterus lumen instead of into veins--> so not luteolytic
how long is gestation of the sow?
what is "lactational anestrus"?
GnRH pulse suppression by prolactin. neg energy balance, stress.
what must happen by day 10 in the sow?
mvt/spacing of the blastocysts
how many blastocysts must there be in each uterine horn?
min 2 per horn
what do blastocysts produce after day 12? what does this cause to happen?
produce ESTROGEN. estrogen causes PGF 2alpha to be secreted into uterus lumen (but not into circulation, so not luteolytic)
what can prolactin do to the sow cycle?
prolactin can suppress GnRH pulses--> lacctational anestrus (or from neg energy balance or stress)
follicular short- 3 days. estrus SUPER short (12-18hrs)
WHEN does ovulation occur in the cow?
apprx 12-18 hrs AFTER ESTRUS (IN METESTRUS)
HOW does ovulation occur?
ovulation (LH surge) occurs once corpus luteum has REGRESSED (via PGF 2alpha) because progesterone inhibits the surge
why is timing of AI so important in cows?
estrus is only 12 hrs and then oocyte survival after ovulation is very short (10 hrs) and sperm survival is short (18-24hrs)
when should cows be inseminated/mated?
during mid to late estrus!!!
what is the most definite sign of estrus?
standing to be mounted=standing heat
when do you see blood-stained mucus with a cow?
apprx 2 days after estrus (=in METESTRUS)
what are swiss people doing to get an edge on cow breeding?
heat detection system-- combined body temp measurement (intravaginal) and motion sensors on neck to send a farmer a msg when shes ready
to establish preg, conceptus produces what? What does it do?
secretes TROPHOBLASTIN (aka interferon/IFN, or bovine trophoblastic protein/bTP) between day 12-30/35(attachment).trophoblastin inhibits oxytocin receptor expression-->no PGF2alpha secretion-->CL remains active, progesterone levels stay high
what is trophoblastin, secreted where, when, why?
by conceptus around attachment, dec oxytocin receptor expression, dec PGF2alpha secretion, CL active to make progesterone to maintain preg
how long is gestation in a cow?
what is EPF-A and EPF-B? when is it made, what does it do?
early pregnancy factor, produced within hours of fertilization and throughout preg- A in oviducts/uterus and B in ovaries. Both A+B required to induce immunological tolerance of embryo.
when is progesterone produced where?
CL till day 150, then placental proges dominant with CL supporting.
what supports fetal growth during preg, and when?
PLACENTAL LACTOGEN ("growth hormone") during second half of preg, supports fetal growth
what rises sharply in last mo of preg? why?
estrogen, in prep for partrution
how is induction of estrus in a cow with an active CL possible?
chemical luteolysis with PGF2alpha! CL in cow responsive to PGF2alpha AFTER CYCLE DAY 7. you can expect the next estrus 4 days later
how can you synchronize a herd of cows? (think of 2 diff situations cows can be in)
Give all cows PGF2alpha. (1) cows with responsive CL (after day 7 of cycle-of die) will undergo lluteolysis--> new estrus after 4 days--> new CL--> responsive to PGF2alpha= DayX + 11. (2) unresponsive cows are in pro,estrus,met, or early die., so on day X+11 they should all have responsive CL, so on day X+11 repeat PGF2alpha for ALL cows, all should have responsive CL, all enter cycle within 4 days
how do you induce abortion/ induce parturition?
PFG2alpha induces luteolysis until day 150 (abortion). Then after day 150, or to induce parturition, you give cortisol (mimicks fetal signal) AND PGF2alpha
21 days, can be longer during transitional period (early season with extended estrus)
how long is estrus?
what are estrus signs?
*usually only see when exposed to a male. Frequent urination, nervousness, clit winking, raised tailhead, no kicking (standing)
what is essential for establishment of preg?
movement of embryo through uterus!! moves 12x/d through entire uterus. (conceptus prolly produces some conceptus factor to inhibit PGF2alpha release)
how long is gestation?
what three things characterize gestation of the mare?
(1) progesterone (2)**equine Chorionic gonadotropin (eCG) and secondary C. luteum (3) estrogen
what produces eCG? when? eCG aka?
trophoblastic cells from chorionic girdle invade endometrium at day 35, which devolop into endometrial cups. THESE produce eCG (equine chorionic gonadotropin), AKA pregnant mare's serum gonadotropin (PMSG). BETWEEN DAYS 35-150
What qualities does eCH/PMSG have? what does it do?
strong FSH/LH qualities. Stims full ovarian cycle with follicle maturation, ovulation, and CL production= SECONDARY CL to assist in progesterone production.
what happens with progesterone during gestation?
CL+secondary CLs (made by eCG/PMSG) until 150, then placental progest.
why does the mare achieve high levels of estrogen during gestation? Explain process.
placental-fetal cooperation. Placenta produces pregnenolone--> fetal gonads convert pregnenolone to DHEA (dehydroepiandrosterone)--> placenta converts DHEA to estrogen.
what is a good indicator of fetal health during gestation?
ESTROGEN LEVELS after DAY 70
what is controversial about parturition in the mare?
maybe cortisol like normal, maybe fetal thyroid hormones
seasonally polyestrus (long day breeder) AND induced ovulator.
average cycle length of queen?
variable, apprx 14-28 days.
describe cycle if NO MATING occurs?
pro= 2 days, estrogen rises. estrus=5-8 days, high estrogen, initiate b/h. INTERESTRUS=mostly 8-9 days, if no mating occurs during estrus--> no LH peak, no ovulation, no CL, non progesterone, follicle atrophy--> return to proestrus (some cats will ovulate spontaneously)
what is the part of the cycle unique to if no mating?
expressed in early progesterone inc after estrogen priming
*what part of the cycle do dogs lack? why?
FOLLICLES LEUTINIZE FULLY BEFORE OVULATION--> SO NO METESTRUS
what marks onset of estrus in the bitch?
what part of cycle is preg similar to?
what happens in anestrus?
FSH rises--> folliculogenesis begins and E levels inc
vaginal bleeding means what?
how do you know bitch is in proestrus?
vaginal bleeding from proliferative endometrium
what happens near the end of proestrus?
LH inc--> leutinization--> estrogen declines and progesterone inc.
pheromone in dogs?
what is happening to hormones/receptiveness during estrus?
inc receptivity, E dec and P inc!!!
when does the bitch LH surge occur?
during early estrus ("day 1")
when does ovulation occur? when does fert. occur?
ovulation 2-3 days after surge, fert 2-3 days after ovulation (1* oocytes need more time to mature)
what weird thing can happen with dogs AND cats? why is this likely in bitches?
superfecundation (same litter, diff daddies)...sperm viable for 7-8 days!
why is there no met in dogs?
b/c follicles already fully leutinized and produce progesterone when they ovulate
what happens in diestrus if not preg?
in monestrus species, no need to luteolyse the CLa and a bitch enters 70-80 day long luteal phase which resembles preg. proges high till day35 then dec, prolactin up from day 30, end is unknown but--> anestrus.
**oversimplification of bitch cycle
like other species, but onset of estrus b/h is delayed (or, E in bitches= late E and ME in other sp.)
how can you determine cycle of a bitch?
vaginal cytology. look for maximum cornification during LH peak= onset of estrus (anest. and die have intermediate and parabasal cells, pro has intermediate cells and RBCs, estrus has the cornified cells)
whats up with maternal recognition of preg?
not required, because Cla remain active anyway.
how long is gestation?
endocrine profile of preg?
similar to diestrus (progesterone, prolactin (inc greater in preg than die), RELAXIN is preg unique, inc from mid gestation, estrogen inc slowly
good indicator of partrution happening soon?
body temp drops by 1*C 12-36 hrs prior to parturition
=DIESTRUS!!= the physiological state in bitches, not a disorder. non preg female can mimic events of parturition, can even become fully lactational if suckling occurs (b/c prolactin release in die)
why might pseudo preg exist?
pack animals, relive alpha female
what is overt pseudopreg?
usually pseudopreg is unnoticed and dissolves sponteneouslly. only overt if severe lactation or mammary gland infection. Tx= anti-prolactins
what is going on with pyometria?
hormonally mediated diestral disorder leading to ascending uterine infections. high prog. levels in die for 2-3 mo with cystic hyperplasia of endometrium.
3 things that make recipe for pyometira?
(1) endometrial growth with stim secretions (proges). (2) depressed myometrial activity, cervix closed (3) local immunodepression= infection time, baby