Exam 2 Flashcards
What is the expected time length for stage 3 of parturition
Should be w/in 3 hours
What is the primarily accomplishment of stage 3 of parturition
Delivery of the placenta
What is an active management step we do suring stage 3 of parturition
Tying the placenta to allow gravity to help deliver it and keep the mare from stepping on it and tearing it
What is one red flag we monitor for during stage 3 of parturition
Retained placenta
About what percentage of the foals body weight should equal the weight of the placenta
About 10%
What is an abnormally heavy placenta an indication of
Placentitis or inflammation
What is the normal weight range of a placenta
9.7-17 lbs
What does an abnormal placenta typically mean
That the foal was compromised
When we are evaulating a placenta what are we looking for
Normal color, tears and if they match up, or holes
Why do we look for holes in the placenta
If there is a true hole in the placenta then there is a chance that a piece of it is still in the repro tract of the mare that could cause infection
Where is a hole most likely to be on the placenta
The non gravid horn
What is the hippomane
Aggregation of minerals that come from the foals urine
Why is the gravid horn’s tissue typically thicker
Because that is where the foal’s legs are so the tissue is thicker to protect from kicking
Why could parts of the placenta be different shades of red
Different times of detachment from the uterus, bruising, or infection
What are normal avillous regions
Cervical star, allantochorian pouch, and insertion of cord
What is the cervical star
Where the placenta connects to the cervix
What is the allantochorian pouch
Part of the allantochoric membrane is folded during development keeping it from developing villi w/ the uterus
Why would the location of the cord develop avillous regions
Because the foal constantly pulls on the cord
What are other normal placental findings
Allantoic pouches, yolk sace remnant, and appropriate autolysis
What is appropriate autolysis
When parts of the placenta detach from the uterus prior to other parts
What is yolk sac remnant
A reminance of the yolk sac that is present in the placenta
What is an allantoic pouch
A little fluid filled sac that was attached to the allantois
What are abnormal placental findings
Large avillous regions, abnormal density of villi, placentitis, thickened placenta, placental hemorrhage, and meconium staining of amnion
What causes large avillous regions
Twin pregnancies and cysts on the uterus
What are reasons for abnormally dense villi
An unhealthy uterus or a fluke occurrence
What is placentitis
Inflammation of the placenta that makes it look like a thick layer of snot
What is thickened placenta caused by
Fescue or placentitis
What is placental hemorrhage
Trauma or rupture of the blood vessels in the placenta
How does meconium stain the amnion
The foal becomes destressed in the uterus and defecate which is a huge infection/pneumonia risk
What is ascending placentitis
Bacteria enters the cervix and infects the placenta near the cervical star
When is a placenta considered retained
16 hrs
Why is a retained placenta such an issue in horses
Horses have a very sensitive inflammatory response
What is the first management step to avoid a retained placenta
Oxytocin injections given around 2 hrs
What are other management steps for retained placenta
Uterine lavage and antibiotics
What is a common cause of laminitis in late gestational mares
Decrease blood flow of the feet
What are three rare mare delivery complications
Uterine tear, hemorrhage, and perineal tear
Why is it better to not sow a perineal tear
If you dont sow it up it would let them heal from the inside out to avoid infection
What are some post partum management steps
Pain relievers, monitor fecal output, feeding, and deworming
What does banamine do as a pain reliever post partum
Blocks prostaglandins
When do mares typically start defecate after foaling
12-18hrs occasionally over 24 but the vets come out to reduce the risk of impaction colic
When do we feed grain to post partum mares
After they defecate normally
Why do we deworm mares post partum
Because they can pass internal parasite to the foal thru milk
When do we not deworm mares post partum
If they are current for the spring
What is involution
When the uterus shrinks down to a normal size and there is repair in the endometrial lining that is assisted by oxytocin and exercise
How long does involution typically take
21 days
What is lochia
Discharge from the repro tract that is the result of endometrial repair process that occurs w/in the first 10 days post partum
What are the two main aspects of post partum foal care
Monitor benchmarks and early identification of red flags
What is eponychium
Soft spongy build up on the bottom of the foals hoof that protects the mares repro tract
What is typical umbilical dip made of
Dilute chlorahex at a 1:4 w/ repeat treatments
What kinda treatmeant is iodine
One time treatment that dries up the stump quickly, can trap bacteria in the umbilical cord, can be caustic to the skin
What are the benchmarks for the foal
Sternal position, suckling reflex, standing up on their own, nursing, begin passing meconium, and urination
When should a foal be in sternal
W/in minutes on their own
When should a foal suckle
Roughly 15-30 mins
When should a foal be up on their own
1-2 hrs
When should a foal nurse
2-3 hrs
When should a foal start passing meconium
3-6 hrs
When should a foal urinate
Roughly 12 hrs
What is the 1-2-3 rule
1 is standing on own 2 nursing 3 placenta
When is APGAR done
Minutes 1 and 4
What does APGAR stand for
Activity, pulse, grimace, appearance, and respiration
What path does the foal take when attempting to nurse
Pheromones are produced that brings the foal to the chest then a different smell takes them to the shoulder then to the udder
How do we test the colostrum
With a colostrimeter, refractometer, and bulb hydrometer
When does foal rejection typically happen
When the mare associates the foal w/ pain or is scared of them
What is patent urachus
When the urachus goes thru the bladder to the allantois and stays open causing urine to drip out bringing a high risk of infection
When does gut closure start
Around 12 hrs of age and is fully closed by 24
What stops as pinocytosis occurs to close the gut
Colostrum absorption stops
What is the goal for passive transfer of antibodies
800mg/dL
When is passive transfer evaluated
Early 8-12hrs and Late 18-24hrs
What makes foals high risk for failure of passive transfer
Agalactia, prelactation, poor quality colostrum, and sick or injured neonate
What can occur if meconium gets stuck
Impaction colic
How do we prevent meconium from getting stuck
Give enemas
What does normal milk feces look like
Pasty yellow that occurs around 12hrs of age
When are medications given to a foal
After vet recommendatoin
What two meds are given to foals at MU to prevent clostridum
Metronidazole and biosponge
What is colstridium
Bacteria that is common in foals
What are red flags in neonates
Sleeping standing, not nursing, sleeping on the back, legs tucked up close to body, sleeping w/ neck out, one leg tucked up and one over its head, and leg abnormalities
Why do foals typically have leg abnormalities
Because of how the foal was positioned in the uterus
What are common leg abnormalities in foals
Flexural deformities, contracture/laxity of tendons, and angular limb deformities
When is laxity typically seen in foals legs
When they are dysmature
When is contracture seen in foals legs
Seen in larger foals
What is valgus
Knees pointing in
Varus
Knees pointing out
What is the order of the mare’s repro anatomy from the outside in
Vulva, vestibule, vagina, cervix, uterus, oviduct, ovaries
How are equine ovaries shaped
Like kidney beans
What are the parts of the vulva
Labia, dorsal commissures, ventral commissures, and clitoris
What is the dorsal commissure
Where the vulva and labial lips meets near the anus
Where is the ventral commissure
The bottom of the vulva
What should the relationshiop of the dorsal and ventral commissures be
They should form a straight line
What is pneumovagina
Air gets into the vagina
How can bacteria get in the repro tract
Thru air or water
How do horses get pneumovagina
If their dorsal comissure is tilted
What is a management stragety to avoid pneumovagina
A caslicks procedure
When does a mare have a caslick in place past 2 weeks prior to foaling
Mares that have a caslicks until they are foaling are mares that have a serios tilt and are at a high risk of getting a pneumovagina that could cause ascending placentitis
What is the vestibule
A piece of tissue that has a tight muscular sphincter that prevent backflow of urine into the repro tract
When is the hymen located
The vestibule
How does the cervix change w/ estrus
The cervix is tone and pale during diestrus but is vascularized and relaxed during estrus
What are unique aspects of the cervix
Longitudinal mucosal folds and the cervix getting so relaxed that the stallions penis can enter the cervix and ejaculates inside
What does the cervix have that protects the repro tract from bacteria
A sphincter
What are the three anatomical barriers of defense
Vulva, vestibule, and cervix
What kind of uterus does a horse has
A bicornuate which means it has a large uterine body and small uterine horns
How does the uterus change w/ estrus
It has tone if it is in diestrus but during estrus the uterus is relaxed and have endometrial folds that fill w/ edema
What are endometrial folds (unique aspect of the uterus)
Lining of the uterus that fill w/ fluid during estrus, assist sperm, and secrete milk/hormones to support the pregnancy
How are oocytes able to hang out in the oviducts
The uterus does not produce PGE keeping the tissue from relaxing
What are unique aspects of the ovaries
They are kidney shaped and the mesothelium has lining that covers the majority of the ovary
Where is the medulla located on the ovary
The outer layer to prevent multiple ovulations from occuring
What is the function of the mesothelium
Limits the location of where the mare can ovulate from
Where is the cortex on the ovary
Located on the inside of the ovary and is where follicles grow
What is the ovulation fossa
Germinal epithelium that is the only place ovulation can occur
What are the natural protective methods against twin pregnancies
Mesothelium, the medulla being on the outer layer, the cortex being on the inside of the ovary, and the ovulation fossa
What shape does a follicle take on as it grows
Tear drop
What is the order of corpus formed
Corpus hemorrhagicum, corpus luteum, and corpus albuicas
What are the different types of follicles
Primary, secondary, graafian, and antrum
What part of a graafian follicle cells produce androgen
Theca interna
What graafian follicle cells produce estrogen
Granulosa cells
What is estrogen responsible for
Endometrial edema, relaxed cervix, and behavioral signs of estrus
When is the onset of puberty
12-15 months
What is the estrous cycle length
21-23 days
What is the estrus length
4-6 days
When is ovulation
24-48 hrs before the end of estrus
How many ovulations are per cycle
Designed to be one but can be 2-3
What is foal heat
The first ovulation after a mare foals this is 5-16 days post foaling however involution has not completed but as long as endometrial repair will be completed by the time the embryo would enter the uterus she can be bred (10+ days post foaling)
What is the most critical aspect of breeding management
Estrous cycle detection
What is the advantages and disadvantages of transrectal ultrasounds
You can visulaize exactly what the horse is doing but you either have to pay somone or have someone at the barn that is an expert as well as have an ultrasound
What is the best way to detect estrus since the follicle can be present during estrus and diestrus
By looking to see if there are endometrial folds present in the uterus
What is a hemorrhagic anovulatory follicle
A follcile that grows but never ovulates and fills like a CH
When are CLs present
ONLY during diestrus
What is fluid in the uterus a sign of
Inflammation
What is the scale for edema
0-4 four meaning there is lots of edema
Why dont we breed unless edema is present
Because there has to be a source of estrogen for us to breed
How can we prodict when ovulation is
The edema spikes than drops 24 hrs prior to ovulation
What will a mare do if in estrus when teasing
Raise tail, urinate, tilts pelvis, steps out wide, and winking
What does a mare do when in diestrus while teasing
Sometimes they are dorsal but for the most part they clearly want nothing to do w/ them
What can affect a mares behavior when teasing
Herd dynamics, wet (lactating) mares, silent heat (mare that shows no behavior estrus signs)
What is seasonal polyestrus
Multple estrous cycles occur w/in a breeding season
What kinda breeders are horses
Seasonal long day breeders
When do most mares typically ovulate
April to September
What is a transition period
When their body is ramping up for the spring season (mid feb to late april) or when they are shutting down for fall (mid sept to late nov)
Can there be variable ovulation during transition periods
Yes
How do the ovaries look during anestrous
Small due to a lack of hormonal stimulation
What does the pineal gland produce
Melatonin
What is the amount of melatonin produced based off of
The amount of daylight the animal is exposed to
What is HPO
Hypothalamic Pituitary Ovarian Axis
What is the dark, melatonin, HPO activity relationship during short days
increase in dark leads to increase in melatonin leads to decrease HPO activity
What is the dark, melatonin, and HPO activity relationship during long days
Decrease in dark leads to decrease in melatonin leads to increase in HPO activity
What are other factors that affects HPO activity
Multple hormones at play, hemispheres, and domestication
How has domestication affect HPO activity
Feral horses have less food so the have a lower BCS so they are incredibly season and follow the forage growth
Characteristics of estrus
Lasts 4-6 days, follicular phase, estrogen is present, behavioral signs of estrus, and ends w/ ovulation
Characteristics of diestrus
17-19 days, luteal phase, progesterone present, non receptive toward stallion, and ends w/ release of prostaglandin
What is the time line for CL maturation
Grows for 5 days then is mature for days 6-13 then regresses for 2 days present a total of 16 days
What determines how much estrogen a follicle produces
The size of the follicle
Where are FSH/LH produced and what stimulates them to be produced
The anterior pituitary and FSH is stimulated to be produced by GnRH while LH is stimulated by GnRH and estradiol
What does FSH affect and how does it affect it
It targets te granulosa cellls and promotes follicular growth then increases the production of inhibin and estradiol
What does LH affect and how does it affect it
Targets theca interna cells and increases androgens (makes estradiol), follicle maturation, triggers ovulation, and CL formation
What is estrogen responsible for
Edema, cervical relaxation, behavioral estrus, spike of estrogen triggers LH production, and can inhibit LH
What is inhibin
Produced by the follicle it decreases the production of FSH to reduce the amount of large follicles being produced
What is progesterone important for
Mammary development, inhibits effect of GnRH regulating LH, and maintnance of pregnancy
What is the path of estradiol
From theca interna cells/granulosa cells, goes to hypothalamus/pituitary/repro tract, prepares for pregnancy, and regulates GnRH, FSH, and LH
What is the path of inhibin
Produced by granulosa cells, goes to the anterior pituitary, allows for dominant follicle selection, and inhibits FSH
What is the path for progesterone
Produced by luteal cells of CL, goes to hypothalamus/uterus/mammary glands, maintains pregnancy, triggers mammary growth and secretions, and regulates LH via GnRH
What is the path of PGF2alpha
Released if MRP does not occur from the uterus, targets luteal cells of a mature CL, and causes luteolysis
What are unique aspects of PGF2alpha
Travels thru the peripheral circulation having little metabolism in lungs and has a greater effect
How is the dominant follicle selected
After the first follicluar wave is over LH is produced allowing all smaller follicles to regress then the second follicluar wave triggers the follicluar growth of the dominant follicle
What happens during the luteal phase
Selection and recruitment of follicles
When is the only time LH is produced
When there is not a CL present
What is the purpose of having two follicular waves
To ensure that there is a much larger follicle comapared to the others for ovulation
When does a dominant follicle start producing estrodiol/inhibin and is receptive to LH
Around 22mm in size
How much of estrodial, FSH, and LH are produced during the recruitment phase
Small amounts of estrodial/LH and large amounts of FSH
How much estrodial, FSH, and LH are produced during the selection phase
Medium amounts of estrodiol/LH and small amounts of FSH
How much estrodiol, FSH, and LH is produced during the dominance phase
Large amounts of estrodiol/LH and small amounts of FSH
What happens when estrogen peaks then drops
When it peaks it triggers the production of LH and it drops due to a drop in FSH production
What increases the production of progesterone
A developing CL
What does luteolysis decrease and what is this triggered by
Decreases progesterone production and is triggered by a spike in PGF2alpha
Agonist
Acts like the hormone yielding similar results
Antagonist
Binds to the receptor but blocks it keeping action from occuring
What is the purpose of using artifical lights to induce early cyclicity
It decreases melatonin production increasing the HPO activity essentially fooling the horse into starting ovulation earlier
What should the artifical lights protocal be if you want your mare to foal in Jan
Should be put under lights around thanksgiving and should be bred around Feb 14th
How long do horses have to be exposed to light in a day
14.5-16 hrs a day
What does domperidone do
It is a dopamine antagonist resulting in an increase of prolactin
What is domperidone used for
Managing fescue toxicosis and to manage mares that have a lack of udder development/milk production
What is ECP
Estradiol Cypionate is an estrogen agonist that must be given IM
What are the uses for ECP
Induces estrus behavior and assists/allows for stallion collection
What does oxytocin do
Increases uterine contraction and triggers milk let down that is usually given IM but can be given IV
What is oxytocin used for
Get rid of inflammation in the uterus, could be used in a protocol for inducing parturition, and induces milk let down
What does prostaglandin do
Induces luteolysis
What is prostaglandin used for
Short cycling but must be given IM only
What is the down fall of using prostaglandin
If you dont know where they are in their cycle you do not know how affective this will be
When is giving prostaglandin effective
5 days after ovulation to ensure there is a mature CL
When will a mare return to estrus
3-5 days aka about a week depending on the waves
How does giving prostaglandin effect the horse
The horse becomes crampy for about 30 mins to an hour so it is important to not allow horses to associate the pain w/ people or to give grain w/in an hour of giving
What does giving LH/GnRH do
Causes a natural release of LH
What is GnRH used for
Induces an ovulation surge but there has to be a presence of estrogen for this to work
What type of surge does horses have
A long surge
When is LH/GnRH effective
Ovulatory sized follicle 35mm or greater and edema must be present
What are the two primary LH and GnRH used
hCG (LH agonist) and Deslorelin (GnRH agonist)
Why is it not recommended to give hCG more than two times a breeding season
Because hCG is foreign proteins to the horse leading them to developing antibodies decreasing its effectiviness this can be decreased when given IV
What is Deslorelin
A slowly degrading gel that does not create antibodies and is administered IM
What does progesterone do
Induces luteal phase and makes the body think they are in diestrus w/ a CL present
What are the uses for progesterone
Supplement to support pregnancy prior to day 120, suppresses estrus behavior, and estrus synchronization
Why is it beneficial to give progesterone and estradiol
It is a negative feedback on gonadotropins the progesterone inhibits LH and estradiol inhibits FSH shutting down their repro cycle making the ovaries small and synchs follicle growth this is also used to synch mares for ET
Why is equine superovulation useful
Induces multiple follicles to grow and ovulate at the same time this is useful when using assisted repro tech
What is typically used to induce superovulation
Recombinant equine FSH this is a reagent for veterinarians
What other things can be used for superovulation but are not readily available due to contamination concerns
Equine pituitary extracts or equine FSH
What is the most common reason mares don’t settle
Improper timing of breeding
What is the second most common reason mares wont settle
Post breeding endometritis
What is post breding endometritis
Inflammation of the endometrium
What causes post breeding endometritis
There is a normal inflammation caused by sperm but some have a hyperreaction from sperm or their immune system is not able to fight off the inflammation or bacteria exposure
What mares are at a higher risk for post breeding endometritis
Older mares and older maiden mares
Why are older madien mares at a higher risk for post breeding endometritis
Part of the health of the repro tract is being used frequently and if its not the cervix isnt as flexible and gets scaring
What are the managements steps of post breeding endometritis
Use semen extender w/ antibiotics, less frequent breeding, decrease volume of semen, lavage w/ saline, induce uterine contractions, and +/- dexamethasone treatment
