Equine Flashcards
(22 cards)
What is the mares cycle length?
21 days
Tends to be longer in the spring and shorter in the summer
How often do mares cycle per year?
80% seasonally polyestrus
20% polyestrus
When is the transition phase?
Between winter anestrus and polyestrus state of breeding season
What characterizes the transition phase?
Erratic and/or prolonged estrous behavior
Small inactive ovaries early
Large ovaries with multiple large follicles late - clinically confusing
ENDS WITH FIRST OVULATION
What is the fall transition phase?
A mystery
When does LH peak?
After ovulation
What months are the transition phase?
Transition - March to April/May
How do the ovaries behave during the transition phase?
They are small hard and inactive early on
They become larger with with multiple large follicles developing and regressing quickly.
Can the transition phase be manipulated?
Yes by adding artificial daylight and exogenous hormone therapy.
Does manipulation of the transition phase shorten it?
No, it just moves up the breeding season.
Which hormone is responsible to estrus?
Estrogen
What does estrus do physiologically to the mare?
Relaxes the cervix and uterus
How does a relaxed cervix assist insemination?
It accommodates the belling of the stallion penis allowing ejaculation directly into the uterus.
Name 3 ways to detect estrus in the mare?
Cervical relaxation via rectal palpation, speculum examination.
Endometrial edema via U/S
U/S of the large follicle suddenly disappears
When does ovulation occur?
24-48 hours before end of estrus.
What is foal heat?
The first postpartum estrus
When is the timing of ovulation best after parturition to maximize fertility and why?
Day 10 or after
Prior to day 10 uterus still has fluid and bacteria from previous pregnancy (not good environment for fertility)
What is the most likely infection causing diarrhea for the foal around 10 days after birth?
NONE it’s called foal heat diarrhea
If the mare gets pregnant during her foal heat what affect will this have on her foaling calendar?
Will get baby early next year.
What is the most predictable part of the mares cycle?
Diestrus
How long is diestrus?
14-16 days
How long is estrus? (Not the cycle)
5-7 days
