Therio- Mare gestation

wilsbach's version from 2015-11-10 22:27

starting with fert

Question Answer
where does fert occur?oviduct
how long is the embryo in the oviduct before it migrates to the uterus?+/- 6d
how long does the embryo remain round and mobile in the uterus after passing from the oviduct?until D 14
what does early preg factor and PGE (prostaglandin E) do, and where does it come from?embryo secretes these, helps with keeping up motility of embryo (helps with material recognition of preg)
what determines maternal recognition of pregnancy?embryo is mobile (mobility affected by embryo secreting early preg factor and prostaglandin E aka PGE) and in contact with all parts of endometrium, and uterus has high tone (progesterone) which helps foal get to all parts of uterus
after how many days does the embryo finally fixate in the uterus, and where?16D, at base of uterine horn
4 ways for us to dx pregnancy(1) failure to return to estrus (2) *palpation per rectum (3) *US (4) hormonal assays
You can dx preg via transrectal US by what day?D12!!!
how can you differentiate an embryo from a cyst?until about D14 the embryo is perfectly round (cysts arent) and then also they have specular reflections (hyperechoic white stripes) which are dorsal and ventral to the round embryo. (cysts dont have these)
How long does an embryo stay perfectly round? when does it begin to lose its shape?round till about D16. after that, it fixates to uterus near base of horn, and starts to lose its shape.
recognize what stages these are!!yeah i know the days are on the pic w/e
from what day can you start to ID the embryo proper with US?D 21
what is this and what stage?This is where you are just able to recognize the embryo proper, so it's day 21
when can you recognize heartbeat with US?D 25
what are we looking at here? this is seeing the heartbeat (D 25)
what is going on here and what stage is it based on this pic? The embryo has moved to the center of the embryonic vesicle, which means it is about D30
when does the embryo move to the center of the embryonic vesicle?D30
when does the embryo move to the top of the vesicle? at this point, what can you see?D40, only allantois is visible
What is going on here? around D40, embryo moves to top of embryonic vesicle. Then by D50, embryo moves to bottom of vesicle and umbilicus is visible
when does the embryo move to the bottom of the vesicle, and what can you see at this point?D50, you can see the umbilical cord days in order of stuff you can seeD12 you can see the round thing. After D16 (say, day 17) it has fixated and is no longer perfectly around. D21 you can see the embryo proper, not just the vesicle. D25, heartbeat. D30, yingyang (embryo at middle of vesicle), D40, at top of vesicle, D50, bottom of vesicle with umbilical cord visible
***what is the most common NON-INFECTIOUS cause of abortion in horses??TWINS
why must you always try to detect if there are twins?most common non-infectious cause of abortion in horses!!!
By when should you "squash" one of the twins in a mare?Need to squash one while still mobile ie before D16, or AT LEAST BEFORE D35 when the endometrial cups appear and entire breeding season will be lost
if you have "squashed" one of the twins to prevent problems, what MUST you do?ALWAYS FOLLOW UP SCANS TO MAKE SURE ONLY ONE SINGLETON IS LEFT
DDx for twin detection is? How can you differentiate from twins?DDx is endometrial cysts-- however, cysts are not mobile and you can map their position
wut dis? these are cysts!! they will not be mobile,you can map them, and will be there before the mare is preg
twins are usually because of what two situations of ovuations?(1) synchronous ovulations (<24h between ovulations) (2) non-synchronous ovulations (>24h between ovulations)
what type of twins (monozygous or dizygous) are horses usually?dizygous (As in, two oocytes)
in the natural world, what usually happens with mares and twins?Usually in 60% of cases, it spontaneously resolves (one of them dies). Usually this depends on implantation site and disparity in size between embryos. Resolution usually happens much more commonly if implanted unilaterally (same horn) bc of competition.
When is the best time to try to sex embryos via US? What are you looking for? which type of horse do you espeically care about sexing with?d55-65 is optimum. looking for position of genital tubercle. Usually care a lot if it is a polo pony (want fillies).
when can you sex the fetus with trans-ABDOMINAL US (as opposed to transrectal)D80-90
Rectal PALPATION preg dx- when can you feel inc cervical and uterine tone?D15-18
Rectal PALPATION preg dx- when can you detect ventral bulge at base of uterine horn?D20-25
Rectal PALPATION preg dx- when can you do ballottment of fetus?D90-120
three DDx for pregnancy via rectal palpation?urinary bladder, pyometra, distended large bowel
name the things in order, with the days in which they occur, of what you can DX preg by via rectal palpationinc cervical and uterine tone D15-18 --> ventral bulge at base of uterine horn D20-25 --> ballottment of fetus D90-120

maintaining, more basics, etc...

Question Answer
why might you want to do a hormone assay instead of/supplemental to rectal palpation?fractious (grumpy) mare, inadequate equipment/facilities, mare size (minies/ponies), compromised rectum, operator inexperience
what are the hormone assays available to check for preg?(1) progesterone (2) eCG (IT SAYS E NOT H) (3) estrone sulphate (4) urinary estrogens (5) early conception factor
*what are the three main sources of progesterone during preg (and the times in which they are sustained)(1) D0-D180 is primary CL (2) D40-90 secondary CLs (induced by endometrial cups) (3) >D60-80 is fetal-placental progestagens to maintain preg
from what days in the preg does the primary CL act as the main source of progesterone?D0 to D180
from what days in the preg do the secondary CLs act as the main source of progesterone?D40-90
from what days in the preg does the fetal-placental progestagens act as the main source of progesterone?greater than D60-80
what must you absolutely keep in mind about detecting progesterone for pregnancies? (DDxs?)NOT DIAGNOSTIC OF PREG--- false positives can be caused by prolonged luteal phase (diestral ovulation) or perhaps there was EED
what are the two serum chemicals you can use to diagnose pregnancy in the mare?eCG and estrone sulphate
eCG aka? where does it come from and from what days can you detect it?equine chorionic gonadotropin, previously PMSG (pregnant mare serum gonadotropin) is secreted from the endometrial cups and can be detected from D40-D120
when might you get a false positive for pregnancy from measuring serum eCG?false positive if fetal death occurs after endometrial cup formation
Estrone sulfate is what, is used to do what, and is detected from what days and comes from what sources?way to dx pregnancy- comes from a luteal source D35-40 and after that fetoplacental source greater than D60---HOWEVER, amounts that are dx of pregnancy is by D90 should be >6ng/ml. Can also be used to check fetal viability prior to 7mo gestation
*what are the two things you can determine from detecting levels of estrone sulfate?(1) pregnancy if by d90 >6ng/ml (2) check fetal viability if prior to 7mo of gestation
*3 things that maintain preg, and WHEN they are being effective at doing this(1) Primary CL (2) D35 to D120 endometrial cups (3) 5 alpha pregnanes from fetal-placental unit
what are endometrial cups and why are they helpful?trophoblastic cells of fetal origin which burrow into endometrium of mare, and then secrete eCG which causes resurgance of 1* CL and developement of 2*CLs
pic of stuff that's maintaining preg when
what type of placentation?diffuse, epitheliochorial
normal gestation length?335-342d
under how many days of gestation would be considered abortion?<300d
from what range of days would a born foal be considered premature and non-viable without care?300-320d
how many days would be considered prolonged gestation?>360d
why might a prolonged gestation be considered pathological?might be path due to fescue tox (ingestion of ergot alkaloids in endophyte fungus ie acremonium coenephialum)

preparation for foaling/foaling

Question Answer
how long before foaling should you introduce the mare to the foaling environment?4-6wk
what are the best and worst places for foaling?Best is outside on the grass. Stall/barn on straw is also suitable. Wood shavings are NOT SUITABLE
why do you want to introduce the mare to the foaling environment 4-6wk before foaling?reduces stress, and allows mare to build up immunity and allows for Ab xfer to colostrum
in the last month, mares should be monitored for..(6)(1) vulvar laxity and edema (2) vulva discharge (cervical plug) (3) relaxation of pelvic ligaments (4) udder development (5) "waxing" of teats (6) changes in composition, consistency and color of milk
what does the vulva start to look like under the influence of relaxin?
what do the sacrosciatic ligaments start to look like under the influence of relaxin?
which hormone is responsible for the teat "filling in", and how do you know when they are close to parturition in regards to the teat? *what is important for you to do at this time?teat fills in under the influence of relaxin. When it is close to parturition, the wax cone "Stopper" falls off and milk start to drip. *NB! COLLECT COLOSTRUM!
how does milk consistency and color change when she is close to parturition?goes from thick, sticky and yellow to more watery, lighter, and less stick as partus approaches
how does the milk's electrolyte and pH change as the mare nears parturition?Na+ dec, K+ inc (cross over with K+ in the last few days), Ca++ inc in the last 1-3d, and pH dec
how do ppl take advantage of the fact that the milk's electrolytes and pH change when nearing foaling? (how do you interpret it?)pH/electrolyte kits (look like urine dip stick tests) to help predict foaling. So, if only 1/5 squares change then there is a <1% chance mare will foal in next 12hr. if 4/5 squares have changed though, then there is an 80% chance mare will foal in next 24hr
3 stages of parturition? (And how long do they last?)(1) preparatory stage (30min-4hr) (2) expulsion of fetus (5-20min) (3) expulsion of placenta (2-6hr)
what three main things are happening during the preparatory stage?uterine contractility increases (contractions aren't visible yet tho!), dilation of cervix, repositioning ("turning") of the foal
what will the mare look like during the preparatory stage?restless, looking at flank, sweating, inc HR and RR. frequent urination, lying down and standing up (this helps re-position the foal), pawing, elevation of tail
how does the foal preposition during the preparatory phase?foal rotates from dorsopubic to dorso-illial to dorsosacral
what does stage 2 (expulsion of the fetus) start with? what then happens?starts with rupture of allantochorion (water breaks), and then there are abdominal contractions and release of oxytocin (feurgesons reflex). Amnion is forced between vulvar lips. STRONG abdominal contractions--> foal is born!
where in the repro tract does the allantochorion break?breaks at the level of the cervix-- amnion remains intact.
when does the umbilicus rupture? where does it rupture?umbilicus will often stay totally intact even when foal is fully out of pelvis. However, it usually breaks when the foal/mare stands up, usually about 1-2 inches from abdominal wall.
should you ligate the umbilicus? should you disinfect it?DO NOT LIGATE unless bleeding excessively. Disinfect with chlorhex NOT BETADINE
what structures are within the umbilicus?the umbilical vessles (2 arteries, 1 vein) and the urachus
expulsion of the fetal membranes usually occurs and is complete in how much time after foaling? When is it retained????usu 30min-3hrs after foaling, >12h is RETAINED
which breeds are very sensitive to retained fetal membranes?friesians and draft horses

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