Equine 2 Flashcards
what is endometritis in the mare and why is it important?
inflammation of the uterine lining/endometrium–>a NORMAL response to semen! Normally the mare removes all the gunk within 48 hours.
If the mare does NOT clear it within 48 hours, the mare is susceptible to post breeding induced endometritis, which leads to infection and endometrial fibrosis if not treated.
this is the most common cause of infertility in the mare
how can you presumptively diagnose PBIE on ultrasound?
accumulation of more than 2cm of fluid in a pocket of uterine fluid, either during estrus or within 36 hours of being bred
what are some ways to prevent and treat PBIE? What happens if the horse doesn’t get pregnant?
uterine flushes prior to and/or after breeding
antibiotics possibly?
if horse doesn’t get preg: cytology and culture of uterus
list some risk factors for PBIE
delayed mechanical clearance: perineal confimration, vaginal stretching (so much space for stuff to grow), cervical dysfunction (stuff can get in), pendulous uterus (uterus hangs over pelvis brim), scar tissue in endo/myometrium
uterine contractility dysfunction: not responding to oxytocin or prostaglandin
what happens if you have a mare that has failed to conceive, or you have a mare that is older than 10? What action should you take?
give prophylactic treatment for PBIE: uterine lavage post breeding, give oxytocin to improve contractility, give PGF2 (AFTER 5 DAYS CL IS STRONG ENOUGH). ONLY give antibiotics if you have a confirmed bacterial culture
if you’re going to do a post breeding uterine lavage, how long after insemination should you wait? What about giving oxytocin
it takes the semen 6 hours to get to the oviduct, so can flush after 6 hours usually using LRS. Can use this to obtain a cytology and culture
also wait 6 hours to give oxytocin
some ways to manage PBIE?
caslicks surgery for horses with bad conformation
use AI vs live cover if possible
use fresh vs frozen semen
use deep horn insemination
investigate semen handling
what is the easiest and most efficient way to prevent bacterial contamination and improve conception rates for mares?
caslick’s vulvoplasty
what is infectious endometritis and how is it different than PBIE? what causes it? CS?
infectious endometritis is often chronic and the result of unresolved PBIE
can be caused by conformation or cervical dysfunction
C/S: vulvar discahrge, in/subfertility
most common causative agents of infectious endometritis?
E coli and strep equi zooepidemicus, either introduced from cervix or at mating
what is required for diagnosis of infectious endometritis?
culture and cytology (evidence of inflammation) using double guarded swab OR low volume uterine lavage is gold standard (more sensitive)
which bacteria lives deep in the glands of the uterus or inside cells, is very good at evading the immune system, not always detectable by culture, and can become activated by PBIE
strep equi zooepidemicus
biofilm formation is often associated with
gram negative strains like E coli, pseudomonas, klebsiella, sometimes strep
what is a biofilm? why are they important?
aggregate of microbial cells adherent to a surface embedded with EPS.
biofilms can help bacteria evade host immune system responses and are often not susceptible to routine treatments, and the bacteria in biofilms are 10-1000x more resistant than free floating counterparts. They are difficult to diagnose and treat and can cause repeat infections
always suspect a biofilm with
a gram negative bacteria
best way to treat biofilms?
antibiotics combined with biofilm disruptors
examples of disruptors: tris EDTA, DMSO
fungal endometritis is often associated with what 2 things?
physical issues of the repro tract (pneumovagina, urovagina, cervical issues)
overuse of antibiotics
pyometra in mares looks much different than it does in dogs. Explain
in horses, it is the result of end stage unresolved PBIE–>infectious endo–>pyo. Horses can have pyo for years and never know, unlike dogs who usually do systemic quickly and can die from it.
what is usually the cause of pyometra?
poor cervical function, conformation and uterine clearance can play a part as well
what are clinical signs of pyometra in the mare?
usually none!
can have chronic or spontaneous discahrge, weight loss, febrile, chronic illness, skin scalding
how do you diagnose and treat pyometra in the mare?
diagnosis: ultrasound & culture
treatment: repeated lavage, cervical stent to help drainage
what are hemorrhagic follicles and why should I know about them?
it happens when ovulation fails and there is bleeding into the follicle. These are painful and can present like chronic colic (pawing at the ground)
what are anovulatory follciles?
not cysts, when a normal follicle “keeps” growing and persists for a varying period of time. eventually they stop growing.
true anovulatory follicles without lutenization can be present for how long?
100 days–>and mares can ovulate around them!
if you find luteal tissue in a horse that has failed to ovulate, how can you “treat” this?
1/10th dose of PGF2alpha daily for up to 14 days to get rid of luteal tissue–>can make horses sweaty, painful, etc
what is the most common ovarian tumor in the horse?
granulosa cell tumors
clinical signs of granulosa cell tumors?
stallion like behavior
what are granulosa cell tumors?
common ovarian tumor in horses, benign and unilateral, can develop during pregnancy, release inhibin so the controlateral ovary will be small, testosterone produced
how do you diagnose a granulosa cell tumor?
ultrasound (look like a honeycomb), a GCT panel (testing testosterone, inhibin, and progesterone), antimullerian hormone
if you have a horse that you think has a granulosa cell tumor but the owner doesn’t want to do hormone testing for diagnosis, what can you do?
give PGF2 alpha and re check ultrasound in a few weeks. If it’s a GCT, it won’t change at all
how are granulosa cell tumors treated?
surgery–>contralateral ovary resumes follicular activity within 6 months on average
how long is equine gestation?
335 to 342 days
around day 6 and then days 10-16 of pregnancy, some PGF2 alpha is released. Why?
allows for mild contractility so the embryo can move around
around day 8 of pregnancy, a capsule is formed. Why?
the capsule prevents embryo from sticking to the uterine lining, so it can move around
around what time does the embryo implant?
around day 16, usually implanting at the base of one of the horns
around what day is a heartbeat detectable?
24, but Tovah likes to check at day 30
function of the capsule around the embryo?
anti-adhesive–>high sialic acid residues
mechanical stability–>withstand uterine contractions
around days 10-16 the cenceptus secretes PGF2 alpha in order to be propelled within the uterine lumen. Why is this so critical?
mobility is important for maternal recognition of pregnancy–>this recognition prevents the endometrium from producing further PGF2 alpha, allowing the CL to remain
what day should you check for twins?
what day is the embyro visible?
what day does the embyro ascend within the vesicle?
day 14
day 21: embryonic vesicle looses its perfectly round shape
day 30
why do you check for twins? why is it this day and not later?
day 14, because fixation happens at day 16
what are endometrial cups? why are they important?
unique to horses, areas where the placenta invades into uterine lining. usually form in the gravid horn around day 36-38. they produce lots of equine chorionic gonadotropin (eCG). may play a major role in maternal immune response/tolerance
what is the role of equine chorionic gonadotropin hormone during pregnancy?
has LH behaviour, some FSH behavior
the pituitary will continute to release FSH to stimulate development of dominant follicles during early pregnancy, and then the LH behavior of eCH will lutenize those follicles to form accessory CLs=more progesterone=maintain pregnancy. basically a built in back up plan
if a pregnancy is lost after endometrial cups have formed, what does that mean for your mare?
the breeding season has likely been lost, because even though the fetus is gone, eCG is still being made, which means progesterone is still being made, and the other follicles lutenize, and there likely won’t be another cycle. Cups can stay for 150-160 days after the fetus is lost. No treatment for retained cups
does the prescence of eCG indicate the prescence of a viable fetus?
no!
how long does the fetus produce progesterone for to maintain pregnancy? why is this important to know?
produces progesterone between days 50-70 and maintains pregnancy after CLs begin to regress. After day 150-180, there is no CL function. At day 150 the placenta can take over producing progesterone. This means you may need to supplement with progesterone until day 150 so the placenta can take over progesterone production.
what are some ways you can prep for foaling?
move the mare to foaling location 1 month prior to foaling to allow time for her to become comfortable in the environment
pre-foaling vaccines should be given 1 month before like tetanus, EEE/WEE, WNV, flu/rhino, as well as any deworming
why do you want to use straw bedding or pasture rather than using shavings?
shavings are dirty and can harvest microorganisms YUCK. Straw is more clean
why do we rarely induce birth in horses?
fetal maturation happens in the last 24-48 hours and you can’t skip this phase!
important things to have in your foaling kit
tail wrap, umbillical dip, enema, gloves, scissors, stethy, thermometer, clean towels, buckets
what are some signs of impending parturition in the mare?
mammary development starts 30 days before, and the mare may spontaneously produce milk in late pregnancy
dropped belly/pendulous abdomen 1 week before
elongation of volva
softening of tail head/loss of tail tone
what are some ways to predict parturition in the mare?
24 to 48 hours before foaling, Ca will increase
3 to 5 days before birth, K will be higher than Na (which is opposite of normal)
describe stage 1 of parturition in the mare
lasts several; hours to several days, appear crampy, sweaty, nervous, etc.
fetus starts to engage with the cervix and pelvic canal, rotation of the fetus, chorioallantois rupture happens at the end of the stage
descirbe stage 2 of parturition in the mare
active pushing that lasts 15-20 minutes, happens very fast, ends with expulsion of the fetus
should see the amnion at the vulvar lips if the chorioallantois has ruptured normally
what happens if you see a “reg bag” or red tissue at the vulvar lips?
this means there is premature placental separation. when this happens the foal is no longer getting oxygen from the placenta and the foal needs to get out ASAP or it will die
describe stage 3 of parturition in the mare. what is the most important consideration for this stage?
can last up to 3 hours and involves passing of the placental membranes, rapid involution of the uterus begins. Retained placental membranes are common and will make the horse very sick–>check to make sure every part of the placental membranes are present after the horse passes it
given that inducing a mare comes with many risks, when would you need to induce a mare?
- prepubic tendon rupture
- prolonged gestation
- hydrops (big swollen fetus)
what drugs would you use to induce a mare?
oxytocin is agent of choice at a low dose
prostaglandins or glucocorticoids can also be used
