10, 11: Clin Exam & Monitor Estrous Cycles Flashcards
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
teaser stallion management: what is key to prevent stallion from becoming bored or restless and “souring”?
let him breed every once in a while
why might a mare fail to demonstrate estrus?
- young maiden mare
- mare w foal by her side
- mare resents individual stallions [many do not like grey stallions]
- stallion NOT adequately expressive to elicit behavior for mare
how is repro tract of mare evaluated?
- palpation per rectum
- transrectal ultrasonography
what is the industry standard for examining the repro tract of mare?
transrectal ultrasonography
what signs are seen on u/s?
estrogenized uterus
size of follicle
what is extremely important to do before rectal palpation of mare?
inform owner of risk - informed consent
what are appropriate methods of restraint during rectal palpation of mare?
stocks
lip twitch
sedation
what is the technique for rectal palpation in the mare?
- locate cervix on pelvic floor
- grasp cranial margin of uterus
- follow cranial margin to ovary
what is the risk associated with rectal palpation?
iatrogenic rectal tear
what is the indication that a rectal tear has occurred?
blood on palpation sleeve
how is the severity of a rectal tear evaluated?
speculum examination
bare are examination
what grade has the worst prognosis? why?
grade 4
b/c mucosa, submucosa, muscularis and serosa is torn -> into peritoneum or retro peritoneal space
what is the risk of using antimicrobials to treat a low grade rectal tear?
colitis
during estrus, what are the characteristics of the uterus, cervix and ovaries?
uterus = flaccid and edematous
cervix = soft, flat with palpable canal, short
ovaries = dominant follicle, follicles of smaller sizes
what are characteristics of the mare uterus, cervix and ovaries during diestrus?
uterus: well demarcated, firm, tubular
cervix: well demarcated, toned, tubular, long
ovaries: follicles of various sizes
transrectal u/s of mare uterus and ovaries during estrus?
uterus: anechoic w prominent hyerpechoic endometrial folds
ovaries: dominant follicles, multiple other sized follicles
transrectal u/s of mare uterus and ovaries during diestrus?
relatively homogenously echoic
ovaries: follicles of various sizes, CL
what makes a follicle appear echoic?
b/c it contains blood
what makes a follicle appear anechoic?
contains fluid
why is measuring repro hormones NOT done routinely on mare to detect estrus?
b/c lag time btwn obtaining a sample and receiving results from laboratory
what physical signs may be seen for a mare in estrus?
- nothing obvious physically - look at behavior
- she may have some dried urine crystals at ventral vulvar commissure
what is a FM alpaca called?
hembra
during what phase is the hembra receptive to the macho? what does her hormone profile look like?
follicular phase
p4 absent
what behavior does the hembra show when she is receptive?
interest in macho
interacts - does not flee or spit on him
kushes nearby a breeding pair
will readily kush for macho and allow mating
what must occur for a hembra to develop a CL?
she must be bred
what hormone will be absent unless she is bred?
p4
what phase is the hembra not receptive? what hormone is present?
luteal phase
p4 present
how does hembra act when not receptive? (in luteal phase)
no interest in macho
spits and flees the male
will not kush for macho
social factors regarding hembra mating: if receptive, why might a FM not kush for M?
if she is older and he is younger / inexperienced
challenges with transrectal u/s on hembra?
small hand required
what method is better than hand for exam of hembra reproductive tract?
rectal probe on an extension
what size follicles of a hembra can be induced to ovulate?
6-8 mm
what is looked at on u/s exam of hembra repro tract?
- presence and diameter of follicles
- endometrial edema
- free fluid in uterine lumen (inappropriate)
what level of which hormone indicates presence of CL on hembra?
over 2 ng/mL of p4
what does presence of CL in hembra indicate?
that she ovulated
what is most widely used indicator of pregnancy for hembra?
presence of CL
what type of cycle/ovulation does a hembra have?
induced ovulator
what behavior does sow show when in heat?
dec appetite
interest in boar
vocalization and “ear popping”
lordosis
what type of exposure to boar is necessary for sow to show interest?
minimum distance btwn sow and boar - direct contact or parading of boar past her
at least 5 mins exposure
boar introduced as novel - so he must be housed away from sows for most of time
what is lordosis? how is it elicited from sow?
why might she become refractory?
- flexing of back Mm
- if constant, due to continual exposure during estrus, she may get muscular fatigue resulting in her being refractory to stimulation
- stim by back pressure test
what changes occur to vulva in FM pig? is it more prominent in gilt or sow?
edema and hyperemia
more prominent in gilt
how often is measurement of hormones used in FM pig estrus monitoring?
not routinely used
how often is repro tract exam used to monitor estrus cycle of pig?
not routinely used
MC practiced estrus monitoring in diary industry?
heat detection - behavior observation
T/F - majority of dairies utilize a bull primarily for breeding
FALSE - dairy bulls are dangerous
only 40% utilize bulls and they are NOT primary means of breeding - they are secondary “clean up” bulls, if AI fails
T/F - majority of beef operations use primarily bull for breeding
TRUE - 80% beef heifers and 95% beef cows exposed ONLY to bull for breeding
what is cow hormone profile during proestrus?
e2 inc and p4 absent
cow behavior during proestrus?
restlessness
dec feed intake
dec milk prod
mounting / “riding” FM that are in estrus
what stage is mounter and cow being mounted in?
mounter is in pro estrus
cow being mounted is in estrus
cow hormone profile in estrus?
high e2 and absent p4
cow behavior in estrus?
inc activity, vocalization (balling), stands to be mounted by other FMs and/or the bull
how efficient is estrus detection?
it is inefficient
60% of cows are seen in heat
20% of inseminations are performed at incorrect time
how long does standing estrus last in cow?
14-18 hours
MC time for cow to express estrus?
6am and 6pm
AM / PM rule
why is behavior observation difficult for producers?
labor intensive
boring
best times occur during family times (AM and PM)
% FM detected in heat related to what?
- frequency and duration of observation periods
1 x 20-30 mins = 50%
2 x 20-30 mins = 80%
3-4 x 20-30 mins = 95%
expression of estrus in cattle impeded by what factors?
- inc ambient temp
- small number FM in heat at same time
- poor footing
- lameness
- low ceilings in old barns
what heat detection aids exist to supplement visual observation?
- talk pain / chalk - put on tail head and is rubbed off when she is mounted
- heat detection patches - mounting activity rubs off top scratch off layer to reveal bright color
- heat watch 2 and pedometer technology - more expensive - tell what cow mounted and how often and for how long
how can teaser bulls be used to aid in heat detection via behavioral observation? what procedures are done to alter them?
still have testosterone
- penile translocation - cannot achieve intromission or bransmit venereal dz
- vasectomy - renders infertile
- marking device worn
how are androgenized cows/heifers or steers used?
- steer has translocation sx and is given androgens
- good use of freemartin heifer
what animals can be used to aid in estrus detection?
- teaser bulls
- androgenized heifers
what physical changes occur during estrus in cow?
clear mucus vulvar discharge [bull string]
mild vulvar edema and hyperemia
from being mounted: ruffled hair at tail base, saliva over withers, rub marks over pelvic bones
physical changes in cow during metestrus? can she still be bred?
bloody mucoid vulvar discharge
NO - too late to breed her
behavior changes are no longer sole means of determining estrus due to development of what?
estrus synchronization and fixed time AI programs
T/F - exam of repro tract is routinely performed in cattle
FALSE - not routinely performed
during estrus, rectal palpation in cow shows what?
- firm, edematous “toned” uterus
- large follicle
T/F - during estrus, measurement of repro hormones is routinely performed in cattle
FALSE - NOT routinely performed
what hormones can be measured in cattle to detect estrus?
p4 - at time of insemination
when is estrus detection relevant in doe?
for in hand breeding or AI breeding
what are primary methods of estrus monitoring in doe?
behavioral observation (may use teaser buck) observe physical changes
at what point in observation does breeding occur in does?
at observed estrus
how long do behavioral signs of estrus last in the doe?
12-48 hours
what behavioral changes can be seen in doe at estrus?
- pace along fence near buck
- stand to be investigated by buck
- urinates frequently
- vocalizes
- lifts and rapidly wags tail [“flagging”]
if a doe is in heat and smells the buck scent (even if it is on a rag), what sign will she show?
flagging
flag her tail
physical changes seen in doe at estrus:
- edema and hyperemia of vulva (sometimes)
- mucoid cervical discharge (seen best thru speculum)
with what sign is needed to breed the doe?
mucus present on vaginal speculum examination
what will mucus look like during estrus?
cloudy [and becomes more viscous]
- is clear before estrus and cloudy at estrus
if mucus after vaginal speculum is clear, the doe is in estrus?
NO -> it is before estrus
- mucus will be cloudy when she is in estrus
what are behavioral manifestations of estrus in ewe?
how long do they last?
- seeks out ram
- allow ram to investigate
- may urinate
30-36 hours
why is behavioral changes in ewe at estrus difficult?
vulvar edema is is variable
thin vaginal mucus discharge
how widely applied is estrus monitoring in the ewe?
NOT widely applied
predominant method of breeding in ewes in US?
natural service
general protocol used when AI used in ewes?
estrus synchronization and fixed time surgical insemination
when estrus monitoring is used in ewes, what method of estrus monitoring is used predominately?
teaser ram - vasectomized or epididectomized
with marking harness or grease paint on chest
estrus monitoring protocol in bitch:
thorough:
behavior observation
observe physical changes/manifestations of heat
examination of reproductive tract
measurement of reproductive hormones
what stages is “heat” used to describe in bitch?
beginning of proestrus until end of estrus
when does bitch display breeding reflexes?
- strengthen through proestrus and estrus
- disappear during diestrus
how can breeding reflexes be elicited from bitch?
by male or through stimulated teasing
what is the purpose of breeding reflexes in bitch?
facilitate “access” for intromission
why might expression of breeding reflexes be decreased in bitch?
maiden
poorly socialized / anxious
extremely dominant
what are breeding reflexes the bitch displays?
teasing - playful interaction
tail flagging
vulvar lift [pouting]
lordosis
when teasing, if bitch will tease him but sit when he mounts, what stage is she in?
pro estrus
if bitch will tease and stand for mounting, what stage is she in?
estrus
what is vulvar life (pouting) in bitch?
brings vestibular canal into a straight path with the vagina, allowing for easier intromission into the vagina
why does M need straight canal?
b/c he has an os penis
what is lordosis in bitch?
standing heat - bracing for mounting of M; leans towards side of pressure application
what physical changes does bitch display in her vulva and is due to what hormonal changes?
swelling:
proestrus - size and turgidity inc under influence of e2
estrus - size and turgidity dec as e2 dec [vulva appears wrinkled]
describe discharge bitch experiences during estrus - origin? hormonal influences?
- endometrium origin
- proestrus: serosanguinous under influence of e2
- estrus: pink/straw colored [seepage subsides w dec e2]
- diestrus 1: foul, pus like discharge for 12-24 hours
how does e2 effect vaginal epithelium? what stage does it occur in bitch?
stimulates hyperplasia
proestrus
what is the function of vaginal hyperplasia of proestrus in bitch?
protective barrier during copuation
what are implications of vaginal hyperplasia in bitch for NTs migration?
hyperplastic cells are dead - lack desmosomes
NTs cannot migrate through these layers and so do NOT enter the vaginal lumen
what stage of estrus in bitch is the vaginal epithelium shed?
end of estrus / beginning of diestrus
what does vaginal epi of btich look like in anestrus / diestrus?
thin
basal level of intermediate and superficial cells
quiescent vagina
bitch vaginal cytology procedure:
- moisten swab w physiologic saline
- obtain sample by gently contacting epithelium on dorsal aspect of vaginal wall, preferably through guarded speculum
- roll swab on slides
- allow to air dry
- stain using Diff Quik
- examine under 100x light microscopy
what is SCI?
superficial cell index - vaginal cytology of bitch
% epi cells that are superficial or dead
physical manifestation of degree of estrogenization of the vaginal epithelium -> reflective of stage in estrous cycle
how is SCI measured?
on cytoloyg slide - count epithelial cells -
NOT RBCs or WBCs - and calculate % dead/superficial cells
what do superficial cells look like on cytology?
separate cells - unlike alive cells (of intermediate layer) which come off together and in sheets
pyknotic nuclei or anuclear
like corn flakes
what do parabasal cells look like on cytology:
large nuc: cyto ratio
what do intermediate cells look like on cytology?
metabolically active, active nucleus, may occur in sheets (b/c alive and connected w desmosomes)
what does anestrus / diestrus look like on vaginal cytology of bitch?
same appearance to spayed bitch smear
few superficial cells - if any
some parabasal and intermediate cells
amorphous debris
few RBCs
bitch vaginal cytology in early pro estrus?
inc cellularity overall
few superficial cells
RBCs and some WBCs
debris and maybe bacT
why are RBCs and WBCs present during pro estrus in bitch vaginal smear?
is this bad?
b/c bacT and NTs migrate out of vasculature of endometrium
RBCs migrate too
do not worry as long as RBCs and WBCs are in proportion with each other
bitch vaginal cytoology in proestrus?
intermediate cells may come off in sheets
inc SCI
dec WBCs
RBCs variable numbers
dec debris (bacT) - b/c being flushed out by discharge
bitch vaginal cytology in late proestrus / early estrus?
SCI reaches 100% prior to LH surge
less debris (bacT)
fewer RBCs and NO WBCs
what if WBCs are present on bitch vaginal smear of estrus?
then they came from the uterus -> suggests uterine infection
bc they cannot migrate thru thick hyperplastic vaginal epithelum
bitch vaginal cytology smear mid estrus?
SCI 100%
NO WBCs
few or none RBCs
debris and bacT maybe
when does mid estrus occur, relative to the LH surge, in bithc?
4 days after
vaginal smear bitch
late estrsu?
large number of cells SCI 100% no WBCs no RBCs usually debris (bacT) intermediate cells may be in "rafts" or sheets, under superficial cells
vaginal cytology bitch
diestrus 1 (out of heat by 1 day)
can she be bred at this time?
abrupt and marked dec in SCI (less than 70%)
WBCs
may see diestrus and foam cells
cannot breed at this time
bitch vaginal cytology
diestrus 1-2 - see diestrus cells. what are they?
diestrus cells - NTs waiting to get into superficial cells and ate into intermediate cell layers
then they appear inside the cells - and release enzymes
how does vaginal smear of bitch change thickness through proestrus, mid estrus, late estrus and diestrus?
pro estrus - thin smear
mid estrus - smear
estrus - thick
diestrus - thin again
what is vestibular cytology of bitch?
swab obtained from vestibular ceiling w/o advancing cranial thru vestibule vaginal junction
why use a vestibular cytology rather than a vaginal cytology?
px air from entering the vagina (do this if she is near breeding time)
preserves vagina as a potential space when vaginal AI is to be performed
how do changes in vestibular smear correspond with vaginal smear?
changes in SCI / NTs / etc are similar to what is seen on vaginal smear
BUT - changes occur 1-2 days earlier relative to the end of estrus
- consider that changes in vagina are delayed by 2 days compared to vestibule
vaginoscopy of bitch shows what?
visual appearnce and moistmess of folds of vaginal mucosa - indicative of predominant hormone (e2 vs p4)
what does vaginoscopy of bitch show during an or di estrus?
thin walls
vaginoscopy of bitch during pro estrus?
edematous w big billowy folds
vaginoscopy of bitch during estrus
shrunken up and dried - pale and angular
b/c thick hyperplastic superficial cells block view of capillary beds in tissue
vaginoscopy in diestrus or if spayed bitch?
pink folds
hormones measured during estrus monitoring in bitch?
LH
progesterone
when does LH surge occur in bitch cycle?
considered day zero - proestrus occurs first and then it is followed by estrus
how long does the LH surge last in bitch?
what does that imply regarding how reliable of a measurement it is?
LH peak lasts 12 hours
hard to catch - so can be impractical if only method employed for estrus monitoring
what are serum p4 levels used to indirectly determine in estrous cycle of bitch?
indirect method to detect LH surge
canine follicles undergo pre ovulatory luteinization - serum p4 increases - at time of LH surge
so LH surge NOT caused by p4 inc -> association is purely temporal
what is gold standard p4 test for bitch serum?
radio immuno assay (RIA)
what is 2 day rule for bitch estrous cycle?
LH surge occurs when p4 gets to 2
2 days later, she ovulates (now, p4 is above 5)
2 days later, she is fertile - oocytes ready to be fertilized )
why does it take 2 days for oocytes of bitch to be fertilizable post ovulation?
b/c 1* oocytes are ovulated - they must undergo meiosis 2 to become fertilizable
overall purpose of vaginal cytology in bitch estrus detection?
- confirm estrogenization of tissue
- indicates the time for initiating serum p4 measurement
- indicates time of END of fertile period
what is bitch vaginoscopy best used for?
indicating time of beginning of fertile period
what is most popular method for bitch estrus detection in US?
p4 levels
manage difficult breeders
provides accurate AI timing
