Reproductive Anatomy and Physiology of the Mare Flashcards
Most sensitive organ to hormonal stimulation in mares?
Cervix.
Cervix:
- Average length in mares?
- Closed and dry under the effect of what hormone?
- low, relaxed, and moist under the effect of what hormone?
- 10-15 cm
- progesterone
- estrogen.
T/F: The cervix is ALWAYS dilatable in mare due to absence of fibrous rings
T
Uterus Anatomy:
- Shape?
- Difference in ovary location compared to bovine?
- Y or T shaped.
2. More lateral than cow
Location and position of repro system in mares cna be affected by:
1.
2.
3.
- distension/movement of intestines
- distension/movement of bladder
- pregnancy
- Describe how the repro tract is attached to the abdominal wall?
- What side effect does this have on palpation?
- two broad ligaments
2. may make ovaries difficult to locate
T/F:
Extensive mesometrium means there is a wide variation in ovarian position
F, extensive mesoVARIUM
- Uterus has how __-___ folds.
- Folds run from ___ to the ___
- Purpose of the folds?
- 12-14
- tip of the horns to the cervix
- aid in fluid evacuation
Functions of oviduct in mare:
1.
2.
3.
- Sperm storage
- Fertilization site
- Embryo transport
- Fertilized ova descends from the oviduct into the uterus how many days after fertilization?
- UTJ opens in response to what?
- 5.5 days after
2. PGE = SUPER IMPORTANT = PROSTAGLANDIN E
Ovaries:
- Location is variable, but usually close to ___
- Site of ovulation?
- 3rd/4th lumbar vertebrae
2. Ovulation fossa
Ovaries:
- Mature follicle is how large?
- What determines the severity of follicular oblongation?
- 40+ mm
2. the further the distance from the ovulation fossa
Mare udder anatomy:
- Teat distribution?
- gland distribution
- two halves with a teat each
2. each half has two glands with one orifice each
Broad pathologic causes of anestrous:
1.
2.
3.
4.
- Infectious
- Lactational
- Senile
- Ovarian (endocrine)
How is anestrus related to melatonin?
short days stimulate the pineal gland to release melatonin that inhibits GnRH production.
Transitional Phase:
- What do the follicle looks like?
- What does the uterus look like?
- Clinical Signs?
- Ends when?
- multiple variable size follicles, 20+ mm
- Has tone and evidence of uterine edema
- displays signs of estrus for variable lengths of time
- Ends with the first ovulation of the year
Methods to reduce the length of the transitional period:
1. 2. 3. 4. 5.
- Progesterone - 150 mgs IM side for 10 days
- Progestagens (altrenogest)
- Dopamine antagonists to reduce dopamine levels in CSF
- Domperidone
- Sulpiride
3 Methods of estrous detection:
1.
2.
3.
- Teasing
- Rectal Palpation / Vaginoscopy
- U/S
If you’re using Teasing for estrus detection, what signs would you expect if the mare was:
- Not in heat?
- In heat?
- Aggressive kicking
2. Receptive winks, urinates
What signs would indicate estrus during rectal palpation / vaginoscopy:
1.
2.
3.
4.
- Hyperemic moist elongated vulva
- Soft cervix
- Turgid uterus
- Presence of a follicle
What would you see on U/S to diagnose estrus?
1.
2.
- Hyperplasia/edema of uterine folds
2. Large dominant follicle
At any stage during diestrus an ovary may contain _____ follicles of ____ - ____ size at different stages of growth and regression
antral
<2 to >35 mm
- Major primary follicle wave starts with what hormone?
2. Finishes with what process?
- Uterine PGF
2. Ovulation
Three goals during breeding season:
1.
2.
3.
- Estrus induction
- Ovulation induction
- Prolong the luteal phase
Natural processes that induce ovulation
1.
2.
- Follicle size > 35 mm
2. Uterine edema (estrogen exposure and LH receptors)
Ovulation Induction Hormones:
1.
2.
3.
4.
- hCG
- Deslorelin injectable (sucromate)
- Deslorelin pellet
- Recombinant LH (rLH)
Advantages of Deslorelin over hCG?
1.
2.
- Highly effective
2. Wider window for treatment
U/S signs of ovulation:
1. 2. 3. 4. 5.
- Decreased turgidity
- Loss of spherical shape
- Apical area
- Echoic spots in antrum
- Serration of granulosa
Two types of follicle evacuation with description:
1.
2.
- Abrupt - 85% FF evacuates in < 1 min
2. Gradual - 85% FF evacuated in 4-5 minutes
T/F: The U/S appearance of the CL is a good indicator of it’s functionality, but not it’s age
F, it’s not a good indicator ofeither
4 Ways to determine you are looking at the CL on an U/S:
- 2.
3.
4.
- Diameter
- Volume or area of the CL
- Luteal tissue echogenicity
- Doppler would indicate vascularization
Possible causes of failure to respond to ovulatory inducing agents:
1.
2.
3.
- Immature follicles = not enough LH receptors
- Mares are not in estrus even though a large follicle is present
- Anovulatory hemorrhagic follicles (AHF)
Clinical signs that would indicate a HAF (hemorrhagic antral follicle)
1. 2. 3. 4. 5. 6.
- Fails to ovulate in response to ovulatory inducing agents
- Increases in size beyond normal
- Numerous free-floating echoic specks in the antrum
- Single fibrin tags floating in FF
- Organized fibrin in antrum
- Interfere with cyclicity
Luteolysis for estrus induction: Drug options:
1.
2.
- Success confirmed via
- PF2a (lutalyse)
- Cloprostenol (estrumate)
- Progesterone levels drop to basal < 1 ng/ml in 24 hours
- CL must be how old to be fully responsive to prostaglandin?
- What can happen if you give luteolytic drugs daily for 3 days?
- 5 days
2. Anti-luteogenic effect
Why is it recommended to examine mares at the time of treatment with luteolytic drugs?
To better predict the PGF response and because failure of this can result in undetected ovulations to further delaying the breeding
Common WRONG ways to use prostaglandins:
1.
2.
3.
- Ovulation induction
- Uterine evacuation post-ovulation
- Induction of Parturition
