Pregnant Mare Flashcards
What is the fertilized embryo’s transport thru the oviduct to the uterus dependent on?
It’s own production of PGE2
What is the extra structure {before it hatches from the zona pellucida} b/t the outer layer of the embryo {trophoectoderm} & the ZP?
Embryo capsule
- forms soon after embryo reaches uterus
- preserves structural integrity for uterine migration
- disappears after day 23
idea is that the ruminant embryo hatches from the ZP & quickly lengthens…
When a mare displays the most intense estrus, what are her likely P4 & E2 levels {relative to each other}?
E2 high
P<b>4</b> low…
T or F:
Mares have a really cool & unique utero-ovarian countercurrent exchange
system for PGF-2alpha.
FALSE
cow, ewe, & sow do
What phase of the estrous cycle of the mare will the uterus appear edematous on ultrasound yielding an “orange
slice” or “wagon wheel” appearance?
Estrus
What are endometrial cups?
Fetal chorionic girdle cells that migrate out of the fetal domain,
into the maternal endometrium {uterus}
- detectable ~day 35
- produce eCG which peaks ~day 60 & disappears ~day 100-150
- provoke vigorous immune response
- → lymphocytes reject the cells & cups are physically expelled from endometrium into uterine lumen → there they invent the placenta & end up on the inside of the allantois hanging as little “pouches”
- Last variable amt of time; death mediated by immune response
Relaxin is produced by the placenta in ______, whereas it’s produced by CL in ____.
Mares;
cows
What’s the difference b/t mares & cows with respect to the amnion & allantois?
Horse: amnion is unattached to allantois {free-moving}
cow: there is an attachment {restricts movement}
We can identify eCG in the lab to diagnose pregnancy from day 40-120. Why would we get false positives? False negatives?
Pregnancy lost but cups remain active;
some horses make little or stop soon {don’t go the full 100 days making eCG}
On a farm call, your client explains his concern for his late-pregnant mare who is starting to “bag up” & starting to lactate, but she’s not due for another couple months. Otherwise, she seems totally fine. What should you be suspicious of?
Placentitis
{*MC: ascending via cervix}
- OR -
{hematogenous via MRLS - eastern tent caterpillar:
make granulomas in GIT → bacteremia → placenta}
Fetus becomes sufficiently stressed that it triggers the pathways for parturition
What is CTUP & what are the normal parameters?
Combined Thickness of Uterus & Placenta
used to diagnose placentitis:
thickness of wall in mm, should be < pregnancy in months
What is Nocardioform placentitis?
refers to a group of G+, filamentous, branching bacT found in soil
- causes sporadic abortion
- hematogenously spread
- site of infection: uterine body or base of horn {not at the cervix}
What are the 2 antimicrobials of choice for treating placentitis?
- Potentiated sulfonamides {gold standard; TMS}
- Ceftiofur
What progestin is used to treat placentitis, that also suppress/synchronize estrus in mares {& sows}?
Altrenogest
- *0.088mg/kg**
- this is 2x the label dose*
How do we induce abortion w/PGF2a in horses?
If you’re early, it works quite well…
but past 3-4 months, you have to give it repeatedly,
may take 5-6 days before abortion happens
Thickened placenta, prolonged gestation, low relaxin concentrations, & no udder development {DA receptor agonists} suggest what pathology?
- Acremonium*-contaminated fescue grass
- *Fescue Toxicosis**
Tx w.DA-antagonists:
- Sulpiride
-
Domperidone
- 1.1mg/kg PO SID, beginning 15d pre-parturition
How is uterine torsion different in the horse from the cow?
cow: happens in 1st stage of parturition, presents as cause of dystocia
horse: mid-late pregnancy, as a cause of colic, rather than dystocia…
What’s the length of gestation?
340 days
{avg.335-342d}
Inactivated vaccines are generally regarded as safe for pregnant mares. What are the modified live vaccines w.established safety?
- EHV-1
- WNV
- intranasal strangles
- intranasal influenza
T or F:
pH decreases {to ~6.6} & High calcium secretion in the udder are good indicators of impending parturition.
true
In the third stage of normal parturition, fetal membranes are expelled. If the placenta is not out within what time frame, is it considered retained?
3 hrs
What is this?
Amnion!
What’s this?
Allantoic adenomatous hyperplasia
As a postpartum precaution, how long before expected foaling should we booster mares with tetanus?
4-6 weeks prior to expected foaling
A foal showing signs of prematurity, but greater than 320 days gestation {<320days would be considered premature}, would be an example of?
immature foal!
T or F:
“Red bag” in the mare is an emergency; hypoxia foal often caused by Fescue toxicosis.
true
Which herpesviruses can cause abortion in the mare?
EHV-1
&
EHV-4
How can Equine Viral Arteritis be transmitted?
- aerosol
- aborted fetus/placenta
- venereally
Equine Viral Arteritis localizes where in the stallion?
- Ampulla
- bulbourethral
