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148 Cards in this Set
- Front
- Back
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What type of breeders are mares?
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seasonally polyestrus (80% will enter anestrus late fall and winter
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What is more important - photoperiod or nutrition and temperature when inducing cycling?
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Photoperiod
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What happens when there is progesterone greater than one in the mare?
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there is luteal tissue
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What is the length of an estrous cycle in the mare?
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21 days
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Are cycles longer or shorter in the spring for the mare?
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longer
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Are cycles longer or shorter in the summer in the mare?
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shorter
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What is the length of pony mare and jenny cycles?
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24-26 days - they are a bit longer
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What is the transition phase in the mare?
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between winter anestrus and polyestrous state of breeding; characterized by erratic and/or prolonged estrous behavior (not abnormal for 30 days)
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What are the ovaries like early in the transition phase? Late?
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Early - ovaries are small and inactive
Late - multiple, large follicles |
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When does the transition phase end in the mare?
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ends with the first ovulation
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What is a characterization of the fall transition phase?
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large, persistent follicles that fail to ovulate; not as well studied or understood and not as clinically important
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What hormone dominates during estrus in the mare?
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estrogen
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What is the species that needs BOTH estrogen and progesterone?
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Bitch
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What happens to the cervix and uterus during estrus in the mare?
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it relaxes - as detected by rectal palpation and/or vaginoscopy
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What does the vagina look like during estrus in the mare?
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pink and moist - see via vaginoscopy; endometrial edema
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Where does the horse ejaculate in the mare?
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directly into the uterus
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Where do mares ovulate?
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out of the ovulation fossa
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What do you palpate in the mare? In the cow?
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mare-follicles
cow-CL |
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When does ovulation occur in the mare?
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24-48 hours before the end of estrus
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How is ovulation detected in the mare?
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by rectal palpation of ultra sound
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Describe some estrus behaviors in the mare.
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-positive attitude towards the stallion
-raising the tail -winking - everting the vulva -leaning into the stallion -urination -estrus detection is difficult in certain mares because of shy, aggressive, protective foaling in mares |
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What is the definition of foal heat?
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the first postpartum estrus; occurs in most mares around day 9
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What will happen if the mare gets pregnant during foal heat?
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you will move the foaling date to an earlier date the following year (move up a month)
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Is it normal for the foal to experience diarrhea during foal heat?
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yes
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What is the most predictable part of the mare's cycle?
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diestrus
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What is the duration of diestrus in the mare?
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14-16 days
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What is the cervix and uterus like during diestrus?
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have moderate tone; under control of progesterone; cervix is tightly closed
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Can follicles be present on ovaries during diestrus?
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yes b/c of biphasic wave of FSH
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Are you able to palpate CL on ovaries during diestrus?
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no b/c they are covered inside a serosal surface; they CAN be visualized by ultra sound
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Where does the mare ovulate?
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thru the ovulation fossa
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When does anestrus occur in the mare?
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from Oct-Nov through Feb, longer in more northern latitudes
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What is the tone of the mare during anestrus?
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very atonic cervix and uterus; like a limp dish rag
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What is behavior in the mare like during anestrus?
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passive towards the stallion
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What is behavior in the mare like during diestrus?
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negative behavior towards the stallion
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What do increased levels of melatonin mean in the mare?
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She is in anestrous and the melatonin has an antigonadotropic effect.
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List three abnormal estrus cycles.
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(1) persistent estrus
(2) persistent anestrus (3) shortened luteal phase |
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What are rule-outs for persistent estus?
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(1) granulosa cell tumors
(2) chromosomal abnormalities due to adrenal estrogens (3) ovariectomized mares - due to adrenal estrogens |
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What is another name for an anovulatory follicle?
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autumnal follicles - bring up follicle, but does not ovulate; causes persistent anestrus
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What can a persistent CL cause?
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Inadequate or lack of PGF and persistent anestrus
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What are common causes of persistent anestrus in the mare?
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(1) winter anestrus
(2) postpartumn anestrus - after foal heat (3) chromosome abnormalities (4) ovarian tumors (5) nutritional anestrus (6) ovarian senescence (7) persistent CL (8) anovulatory follicle |
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What can cause persistent diestrus in the mare?
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(1) pseudopregnancies - in bred mare whose babies were resorbed
(2) |
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What can endotoxins do to the mare's cycle?
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-can cause a shortened luteal phase because the toxin causes the release of PGF from the body
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What does inflammation of the uterus cause in the mare?
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a shortened luteal phase due to release of PGF
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What can cause inflammation in the mare's uterus?
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(1) bacterial endometritis
(2) infusing saline into the uterus - to induce abortion (3) invasive diagnostic procedures |
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Where does fertilization occur in the mare?
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in the oviduct
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What is considered early gestation in the mare?
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ovulation to day 40
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When do fertilized ova reach the uterus?
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day 6-7
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Do unfertilized ova reach the uterus?
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NO
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When does embryonic mobility end in the mare?
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day 16
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What is location of the pregnancy related to?
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location of the CL
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How much does the amnionic vesicle grow each day?
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1mm/day
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What is the cervix and uterus like during early gestation?
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-there is extreme tone of the cervix and uterus at day 21; the cervix is tight and dry
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Can the mare show signs of estrus or stallion-like behavior when pregnant?
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YES
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When diagnosing pregnancy in the mare, how big is the uterine swelling at day: 28
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golf ball
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When diagnosing pregnancy in the mare, how big is the uterine swelling at day: 35
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soft ball
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When diagnosing pregnancy in the mare, how big is the uterine swelling at day:
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becomes fluctuant
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When diagnosing pregnancy in the mare, how big is the uterine swelling at day: 60
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football
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When diagnosing pregnancy in the mare, how big is the uterine swelling at day: 90
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basketball
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When do endometrial cups form?
Does disruption of the pregnancy disrupt the life span of the cups? |
day 40
NO |
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What do endometrial cups do?
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produce eCG (PMSG)
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What happens during the endometrial cup phase?
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chorionic girdle cells invade the endometrium
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Will mare cycle while endometrial cups are functional?
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No
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What does eCG (PMSG) do in the mare?
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acts like LH in the mare - luteinizes/OVULATES follicles = secondary CLs
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What does eCG do in other species (not the mare)?
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acts like FSH
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What maintains the pregnancy in the mare during day 100-330?
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the placenta; there is NOT measurable progesterone in the serum
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Are ovaries necessary for the 100-330 day period of pregnancy in the mare?
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no
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What is produced by the fetal gonads during day 100-330 in the mare's pregnancy?
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estrogen and it is excreted in the urine
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How do you diagnose pregnancy in the mare?
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(1) rectal palpation -uterus pulled over the brim of the pelvis -fetus palpable by the 7th month
(2) urine estrogen (Cuboni test-Premarin) (3) Transabdominal U/S |
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What is the prognosis for a prepubic tendon rupture?
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poor - starts with plaque and edema
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When does uterine torsion occur?
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late gestation
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What happens during uterine torsion?
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the broad ligament is pulled to one side and can be corrected either manually or surgically
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How do you predict parturition in the mare?
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(1) milk calcium
(2) relaxation of pelvic ligaments (3) distension of mammary tissue (4) waxing (5) elongation and relaxation of vulva |
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What is the gestation length in the mare?
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variable (305-400 days)
-average is 330-345 (11 months, 11 days) |
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When do most births occur?
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at night
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What factors can affect gestation length in the mare?
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(1) male vs. female fetus
(2) time of year (3) fescue toxicity |
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Name some outward signs of first stage parturition.
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-slight sweating
-restlessness -getting up and down freqently -attempts to urinate -frequent passing of feces -yawning |
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What position is the fetus in during late gestation?
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lying on back in fetal position BUT repositions itself by extending front legs and neck while twisting into dorso-sacral position
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What helps the mare dilate the cervix?
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fetal pressure against the cervix
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What does stage 2 parturition begin with?
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breaking water - release of allantoic fluid
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What position does the mare get in to push the baby out?
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lateral recumbency, BUT mare might get up and down to help position the foal for delivery
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What is the average duration of active contractions?
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groups of 3-4 for 20 minutes, followed by a rest period of 2-3 minutes
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What will happen if 2nd stage parturition in prolonged in the mare?
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foal will die due to detachment of the placenta and anoxia
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What occurs during third stage parturition in the mare?
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passing of the placenta (mare may show signs of colic); should pass an inverted placenta within 3 hours
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What do you need to do once the placenta is passed?
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examine placenta for missing remnants - retained in uterus
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What is a cervical star?
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The site on the placenta where it was attached to the cervix.
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What are the three components to a breeding soundness exam?
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(1) history
(2) mare status (3) physical exam |
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What are two main components of history as part of the breeding soundness exam for the mare?
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(1) age - (decreased fertility after age 12)
(2) breeding history - very important predictor of future fertility |
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What are the three types of mare statuses as part of a breeding soundness exam?
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(1) foaling mare
(2) maiden mare (3) barren mare |
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What is the most maiden type of mare?
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Foaling mare because she has just shown she is able to do it
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What are four important aspects of a physical exam in a mare during a breeding soundness exam?
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(1) overall general health
(2) external genitalia (perineal conformation) (3) rectal exam (including ultrasound) (4) vaginal speculum exam (vagina can get damaged during birth or can grow shut |
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How do you test for pneumovagina?
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-take lips and separate - if you hear a sucking noise, then junction is not doing its job
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What do the presence of WBCs mean during uterine cytology in the mare?
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evidence of inflammation
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What are you looking for by doing a uterine culture in a mare?
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bacteria - there should be none in the uterus
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What does a grade I endometrial biopsy score mean in the mare?
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>80% foaling rate
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What does a grade II endometrial biopsy score mean in the mare?
IIA? IIB? |
mild-moderate changes
IIA=inflammation - 75% foaling rate IIB=inflammation with mild fibrosis - 50% foaling rate (not enough functional endometrium) |
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What does a grade III endometrial biopsy score mean in the mare?
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extensive fibrosis <10% foaling rate
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What kind of test would you use on a maiden mare with an abnormal reproductive tract?
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chromosomal karyotype
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What would you use to look for adhesions or other gross abnormalities?
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endoscope - used in chronic infertility cases
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What is the most COMMON cause of infertility in the mare?
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Endometritis
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What are common pathogens of endometritis?
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Strep
E.coli Pseudomonas Klebsiella yeasts |
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What is CEM and where did it come from?
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Contagious equine metritis - from Europe (venereal)
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What are causes of endometritis - how do bacteria get in there and cause inflammation?
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(1) poor perineal anatomy
(2) inability of uterus to evacuate (fluid in the uterus) (3) poor local immunity (4) acute vs. chronic |
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What drug would you give to treat endometritis?
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oxytocin to to cause uterine contractions
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When do you know when you are done with a uterine lavage? What is it used for?
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-until the fluid is clear;
-standard treatment for endometritis |
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What percent DMSO would you use to treat endometritis and what will it reduce?
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30% - will reduce fibrosis
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What is the difference between treatment in the bitch and the mare when treating endometritis?
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bitch ---> use prostaglandins
mare ----> use oxytocin |
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Where is a persistent hymen?
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at the vagino-vestibulo junction
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What does prostaglandin do in the mare?
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-lyse CL
-elective abortion - best less than 40 days -induction of ovulation (not reliable) |
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What is oxytocin used for in the mare?
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(1) induction of parturition
(2) treatment of a retained placenta (3) uterine evacuation |
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What is hCG used for?
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(1) induction of ovulation - 24-48 hours later (acts like LH)
(2) hormonal diagnosis of cryptorchid testicles in the horse |
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What is regumate?
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altrenogest - an oral progestin
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What is regumate used for?
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-to manage the transitional phase in mares
-control estrus behavior in mares and stallions -to maintain pregnancy |
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What is progesterone use for in the mare?
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-controlling stallion-like behavior in geldings
-delaying foal heat -pregnancy maintenance |
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What is deslorelin?
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-a potent GnRH analogue
-an implant (short acting) or injectable |
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What does Deslorelin do?
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-induces ovulation
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Name some problems experienced with using Deslorelin.
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-although it induces ovulation in the mare, there may be some delay in return to the next estrus if the mare does not get pregnant
-SOLUTION: remove implant after 48 hours |
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What are the best results for breeding management in the mare?
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pasture breeding
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What is the most common type of breeding management?
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hand breeding
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When do you start breeding the mare and then how often?
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-breed the 2nd day of estrus and every other day until out of heat
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What breed is birth day closest to 1 January the most important? And when does their breeding season begin?
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TB
-15 February by light manipulation (16 hours of light) |
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What does regumate do in the mare?
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mimics luteal phase (transition phase ends at first ovulation - the first luteal phase), therefore helps the mare get out of transition phase
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How many days do you continue therapy with regumate?
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14 days - give PGF with the last dose of regiminate
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What is the vet's job in breeding management?
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-rectal U/S of uterus and ovaries
-predict when ovulation will occur -GOAL: limit to one breeding per cycle and get pregnant in as few cycles as possible -ID and treat problem mares |
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What does vaginoscopy tell you about the mare's cycle?
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ESTRUS: cervix is relaxed
DIESTRUS/PREGNANT: cervix is tight -observe any discharge from cervix/uterus and urine pooling |
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How do some farms detect heat in the mare?
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use a teaser stallion
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What are two methods of hormone management for breeding in the mare?
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(1) prostaglandin: lyse the CL and estrus is expected in 3-5 days
(2) hCG or Ovuplant (deslorelin): induces ovulation; ovulation expected in 24-48 hours (follicle size is 30mm) |
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How is shipped, cooled semen managed?
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like fresh semen
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How long is cooled semen good for when cooled to 4 C?
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72 hours
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What is the GOLD STANDARD for shipping cooled semen?
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Equitainer
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How is shipped, cooled semen placed in the mare?
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COLD, with examination for motility
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Does frozen semen have increased or reduced longevity?
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reduced
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How much time do you have to breed with frozen semen post ovulation?
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4-6 hours
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When would you do an U/A to diagnose pregnancy.
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day 11-14 post ovulation; NEED to ID twins
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When would you do rectal palpation to diagnose pregnancy?
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day 20-21 post ovulation
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When are most pregnancies lost?
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-prior to day 42
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What is the leading cause of non-infectious abortion in the mare?
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twins
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When is transabdominal abortion done in the mare?
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day 120
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When is it BEST to treat a twin?
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prior to day 20.
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What is the most common case of INFECTIOUS abortion in mares?
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EHV-1
-vaccinate at 5, 7, and 9 months (3 and 11) |
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What is responsible for rescue toxicity?
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fungal endophyte
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What are clinical signs to fescue toxicity?
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-agalactia (no udder development)
-prolonged gestation -thick placenta -poor foal viability and hyothyroidism |
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How would you treat fescue toxicity?
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remove mare from fescue at day 300; dopamine antagonists (increase prolactin levels)
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What are two dopamine antagonists used in the mare?
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(1) domperidone
(2) reserpine - a long acting tranquilizer |
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What would you check if you suspected Klebsiella or Pseudomonas in the stallion?
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-check the seminal vessicles in a rectal palpation
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Where would you culture bacteria from in the stallion?
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-urethra, urethral fossa, shaft of penis, prepuce
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What do you evaluate stallion semen for?
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volume, concentration, motility, morphology
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What can happen if you get overzealous in cleaning a stallion's prepuce?
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can get Klebsiella or pseudomonas - knock out good bugs and leave the bad bugs
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What does EHV-3 cause?
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coital exanthema - blisters - stallion is often an asymptomatic carrier
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