Mare Cycle and Breeding Management Flashcards
What is the site of fertilization in the mare?
oviducts (uterine tube)
How long is the estrus cycle in the mare?
21 days
What is the transition period?
- gradual increase in FSH after winter anestrus
- growth of several follicles that do not ovulate (waves)
- slow increase in LH until first ovulation of the year
What are the requirements for inducing ovulation in the mare?
- mare must be in estrus
- must have growing, pre-ovulatory follicles > 35mm
What is used to induce ovulation in the mare?
- hCG
- GnRH (Deslorelin acetate)
What is used to shorten the luteal phase?
Prostaglandin F2a
Dinoprost, Cloprostenol
What is used to prevent estrus?
- Progesterone + Estrogen
- Progesterone
- Marble
- OVX
- Vaccine/GnRH implant
Describe the cervix during estrus
relaxed, edematous, moist, pink, and dilated
Describe the cervix during diestrus
closed, pale pink, dry, and elevated off vaginal floor
Describe the cervix during pregnancy
tightly closed and coated with mucus
Describe the cervix during anestrus
relaxed near vaginal floor
vaginal mucosa is white with sparse vasculature
When should the mare be inseminated?
< 48 hours prior to ovulation
What is the ideal vulva conformation?
- vertical
- 10cm
- below ischial arch
What is the rate of growth of follicles?
3mm per day
When does ovulation occur?
2 days before the end of behavioral estrus
Describe embryo transfer
- embryo produced in vitro
- recovered from donor during preimplantation stage
- transferred to synchronous recipient via a straw or surgical implantation
Describe oocyte transfer
- recover oocyte from pre-ovulatory follicle
- surgical transfer to synchronous recipient tube
- mating/insemination of recipient
Describe gamete intrafallopian transfer
- sperm is transferred with oocyte
- fertilization in natural environment
Describe intracytoplasmic sperm injection
- oocyte matured in vivo or in vitro
- sperm injected directly into oocyte
- embryo cultured in vitro
- blastocyst transferred on day 7-8
Describe cloning
- oocyte developed to maturity
- oocyte nucleus removed
- nucleus of cultured somatic cell injected into oocyte
- culture to blastocyst and transferred to recipient
What are the physical barriers to uterine infection?
- vulva and perineal body
- vestibulovaginal junction
- cervix
What are endometrial cysts?
dilated lymphatics
What date is the average first ovulation in the Northern hemisphere?
April 7
What is Turner’s Syndrome?
- XO karotype
- small stature and small ovaries
Which organisms are most likely involved in persistent post-breeding endometritis?
- B-hemolytic streptococci
- Klebsiella pneumoniae
- Enterobacter cloacae
What are the treatment options for persistent post-breeding endometritis?
- small, frequent doses of oxytocin
- post-breeding lavage
- PGF2alpha
- manual cervical dilation
- corticosteroids (Dex, Pred)
What is the embryo capsule?
- polysaccharide-rich membrane between trophectoderm and zona pellucida
- forms after embryo reaches uterus
What are the signs of impending embryo loss?
- small embryo for age
- anembryonic vesicle
- abnormal location and orientation
- endometrial edema during pregnancy
What are the methods of twin reduction and their respective time-frames?
14-15 days - manual reduction
30-50 days - ultrasound guided puncture
60-90 days - fetal decapitation
> 100 days - intracardiac injection
What is the average length of gestation?
335-342 days
Pneumabort-K is a vaccination against what?
EHV-1
