10, 11: Clin Exam & Monitor Estrous Cycles Flashcards
(163 cards)
4 methods of estrus monitoring
- behavior observation (for heat detection) [less expensive]
- observe physical changes [less expensive]
- exam repro tract
- measure repro hormones
when observing the FM, what does the clinician take note of?
FM to FM interactions
her breeding reflexes
some methods to detect heat:
observation
use intact teaser M [unable to achieve intromission]
use surgically altered M [has libido but cannot achieve intromission]
misc: pedometers, feed intake, etc
what is a gomer bull?
surgically latered M with his penis deviated to the side so he can urinate but cannot impregnate FM
what physical changes can be observed for a FM in estrus?
edema and hyperemia of vulva
presence and change of appearance in vulvar discharge
what causes the edema and hyperemia of the vulva?
estrogen (e2)
what do changes in the repro tract allow us to “measure” indirectly?
changes in repro hormones
specifically, e2 and p4
what parts of the FM repro tract are monitored to detect estrus?
- ovary (ovarian dynamics)
- u/s appearance and feel of the uterus
- appearance of cervix and/or vaginal mucosa
in what species is cytologic composition of the vaginal or vestibular epithelum used?
dog
what is the MOST DIRECT indicator of estrous cycle status?
measurement of repro hormones
why is monitoring estrous cycles via direct hormone levels not done often? and in what species is it most commonly done?
- impractical b/c estrus is rapidly progressing in most species
- MC done for the bitch
what hormones are measured in the bitch to detect estrus?
LH
p4
what is the strongest modulator of sexual behavior in the mare?
progesterone (p4)
the presence/absence of p4, more so than the presence of e2, dictates how a mare will respond to the advances of the stallion
in what stages of the estrous cycle is the mare in heat?
pro estrus and estrus
when a mare is in heat, what are relative levels of p4 and e2?
p4 absent
e2 high
what days of the cycle is the horse in estrus?
days 3-7
what physical signs are noted when the mare is in heat?
arches back and lifts tail
postures and urinates [breaks down]
‘welcomes’ advances of stallion, approaches stallion, reluctant to leave stallion
how long post ovulation might a mare demonstrate estrus?
48 hours post ovulation
why does a mare continue to show heat after ovulation
b/c e2 levels are still high
what are signs of diestrus in mare?
- rejects advances of stallion
- pin ears
- clamp or twitch tail
- move away from stallion
- kicks
what are relative hormone levels for mare in anestrus?
p4 absent
e2 low
what is vernal transition? what are hormone levels during this time?
- when p4 absent and e2 high
- frequent intervals of receptivity about every 10 days corresponding w developing follicular waves, before first ovulation of the season occurs
- may be more constant in som mares, for 2 mos before 1st ovulation of season occurs
what are most preferred method of teasing a mare?
and what are less desirable methods?
- along tease rail with mare in chute and stallion in paddock
- mare in stall, stallion outside
- stallion in tease box, mare outside
- direct close contact or over a fence are less desirable
what are issues with group teasing in mares with a stallion confined to a small enclosure w/in a pasture or along a fence line?
- confounded by social hierarchy amongst mares -> submissive mares may NOT get opportunity to get close enough to express heat