exam 3 Flashcards
Oocytes (2n) begin meiosis I during ____________ and are arrested in __________ and remain dormant until after puberty.
Meoisis I then resumes when an _______________
Oocytes (2n) begin meiosis I during fetal development and are arrested in Prophase I and remain dormant until after puberty.
Meoisis I then resumes when an individual follicle is recruited (in adult life)
What stage of meiosis if the oocyte arrested in from fetal development until puberty
Prophase I
When does Meiosis I resume again in the oocyte
when the individual follicle is recruited (in adult life)
What stage is the oocyte of the dog in when they ovulate
Prophase I of meiosis
What is polar body
a small haploid cell that is formed at the same time as an egg cell during oogenesis, but generally does not have the ability to be fertilized
Meiosis II of the oocyte begins when the follicle is recruited for further development but it is arrested in
Metaphase II
What stage of meiosis is the oocyte in at ovulation
Metaphase II
*meiosis resume so only if the oocyte if fertilized by a sperm
In the dog, the oocyte is only in prophase I at ovulation
In most species, the the oocyte is in ______ at ovulation but in the dog they are in _______ at ovulation
Metaphase II
Prophase I
What is released at ovulation
cumulus-oocyte complex
What picks up the cumulus oocyte complex after ovulation
the infundibulum of the oviduct
it is then transported distally to the ampulla region
What are sperm reservoirs
sperm attach to the epithelium of the female reproductive tract (cervix, uterotubular junction or distal isthmus where they are eventually released and travel proximally by the oviduct
Where are sperm reservoirs
sperm attach to the epithelium of the female reproductive tract (cervix, uterotubular junction or distal isthmus where they are eventually released and travel proximally by the oviduct
Sperm Capacitation
changes in the glycoproteins on the surface of the sperm plasma membrane
alteration of the lipid structure of the sperm plasma membrane leading to hyper-activated motility
What is the result of sperm capacitation
alteration of the lipid structure of the sperm plasma membrane leading to hyper-activated motility to now be able to penetrate the cumulus oocyte complex
sperm penetrate through the __________ surrounding the oocyte
cumulus cells
Where does the sperm bind to on the oocyte
Zona pellucida (ZP3 molecule)
What triggers the acrosome reaction
influx of calcium
the outer acrosomal membrane then fuses with the sperm plasma membrane leading to acrosomal enzymes being release to digest a pathway through the zona pellucida
What is the acrosome reaction
influx of calcium triggers the outer acrosomal membrane then fuses with the sperm plasma membrane leading to acrosomal enzymes being release to digest a pathway through the zona pellucida
Once the sperm is hyperactivated and acrosomally reacted it is able to pass through the ___________ into the _________
zona pellucida into the perivitelline space (between the zona pellucida and the oocyte plasma membrane)
Where is the perivitelline space
(between the zona pellucida and the oocyte plasma membrane)
What happens once the sperm is in the perivitelline space
it is able to bind to and subsequently fuse with the oocyte plasma membrane (binding site on sperm is only exposed after acrosome reaction)
the sperm is then internalized into the cytoplasm of the oocyte
What allows exposure of the sperm binding site to the oocyte plasma membrane
after the acrosome reaction
What occurs once the sperm enters the cytoplasm of the oocyte *
Cortical reaction: sperm releases phospholipase zeta into the oocyte cytoplasm and triggers a release of calcium from internal stores
this causes release of cortical granules into the perivitelline space
alters the zona pellucida and prevents penetration by additional sperm (zona hardening)
Cortical reaction *
sperm releases phospholipase zeta into the oocyte cytoplasm and triggers a release of calcium from internal stores
this causes release of cortical granules into the perivitelline space
alters the zona pellucida and prevents penetration by additional sperm (zona hardening)
What happens so the oocyte does not get fertilized by multiple sperm *
cortical reaction
sperm releases phospholipase zeta which releases calcium and this releases cortical granules into perivitelline space to harden the zona pellucida
What is zona hardening * know this
Cortical reaction: sperm releases phospholipase zeta into the oocyte cytoplasm and triggers a release of calcium from internal stores
this causes release of cortical granules into the perivitelline space
alters the zona pellucida and prevents penetration by additional sperm (zona hardening)
blocks to polysperm
-Limitation of number of sperm entery oviduct
-limitation of number of sperm in sperm reservoir
-limitation of sperm arriving at site of fertilization (ampulla)
-limitation of sperm penetrating cumulus
-plasma membrane block - prevents binding/fusion of additional spermatozoa
-zona pellucida block (zona hardening)
Where does fertilization take place
ampulla- isthmus junction
What allows meiosis II to resume with fertilization
Ca++
What occurs during zygote formation
Meiosis II resumes (stimulated by Ca2+)
Second polar body is extruded
Male and female pronuclei form and fuse
Chromosomes are duplicated (mitosis) and the cell cleaves into two blastomeres
zygote
where there is two sets of DNA- male and female
What happens once male and female pronuclei form and fuse
chromosomes are duplicated (mitosis) and the cell cleaves into two blastomeres
How long does it take blastomere cells to divide
every 12-24 hours
*each division results in smaller individual cells
developing embryo that is 16 to 32 cells (maybe 64? too)?
Morula
what is the second membrane, that only horses have that surround the embryo
capsule (also zona pellucida)
forms when blastomeres secrete fluid within the center of the embryo
blastocoele
What is the outer layer of the embryo called once the blastocele forms
trophoblast- forms the placenta
What part of the developing embryo forms the placenta
trophoblast
the inner cell mass develops into the
fetus
What occurs at the ampulla- isthmus junction
fertilization
What occurs once fertilization occurs at the ampulla- isthmus junction
the developing embryo is transported distally through the isthmus and into the uterus by oviductal smooth muscle contractions and ciliary movement
When does the embryo enter the uterus in the cow
4 to 7 days
When does the embryo enter the uterus in the pig
3.5 days
When does the embryo enter the uterus in the mare
5.5 to 6.5 days
When does the embryo enter the uterus
3.5 days (pigs)
4 to 7 days (cow)
5.5 to 6.5 days (mare)
*at morula or early blastocyst stage
At what stage is the embryo when it enters the uterus
at morula or early blastocyst stage
T/F: only viable equine embryos are transported distally through the isthmus and pass through the UTJ into the uterus
True
this is different from the cow because when you flush the cow’s uterus, you will get UFOs and fertilized oocytes
What allows embryo passage through the oviduct in the horse
Must product prostaglandin E2 which relaxes the inner circular smooth muscle of the oviduct and allows embryo passage
What relaxes the inner circular smooth muscle of the oviduct and allows viable embryo passage in the isthmus of the horse
PGE2
In the horse, only __________ are transported distally through the _________ and pass through the _______ into the uterus
viable embryos are transported distally through the isthmus and pass through the UTJ into the uterus
*done via PGE2
zona hatching
embryonic development creates pressure
a small crack eventually occurs in the zona pellucida
the blastocyst stage embryo squeezes out through the crack “hatching” in ruminant embryos
What do equines do instead of zona hatching
they do zona thinning
equine embryos expand and the zona thins and is subsequently shed
Zonna thinning
equine embryos expand and the zona thins and is subsequently shed
only in horse
glycoprotein capsule between the trophoblast cells and zona pellucida in vivo
Equine Embryonic Capsule
*keeps embryo in the spherical shape
What is the function of the Equine Embryonic Capsule
keeps embryo in the spherical shape after zona thinning and shedding
what is the hormone required by all females to maintain pregnancy, especially early on **know this
Progesterone
-inital source of progesterone is corpus luteum of the ovary
-in some species, progesterone and other progestins are eventually produced by the placenta
T/F: goats are entirely reliant on their corpus luteum throughout pregnancy
true
When does maternal recognition of pregnancy occur in the mare
about 14 days
T/F: it is helpful to supplement progesterone to maintain pregnancy
there is little clinical evidence to support the routine use of supplemental exogenous progesterone in order to maintain pregnancy
however the use of exogenous progesterine os common in mares (Regumate)
large animal embryos must signal the uterus to prevent the secretion of prostaglandins and subsequent luteolysis
a decrease in progesterone production would result in pregnancy failure
Maternal recognition of pregnancy
How is maternal recognition of pregnancy achieved in bovines and ovines? *
embryos secrete interferon tau which inhibits the production of oxytocin receptors in the endometrium so that oxytocin cannot stimulate prostaglandin F2a synthesis
embryo elongate in their ipsilateral uterine horn to the CL
this elongation allows IFN-t produces by trophoblast cells to contact the entire ipsilateral endometrium to signal MRP
this is important relative to counter current transport system
Interferon tau
secreted by bovine and ovine embryos and inhibit the production of oxytocin receptors in the endometrium so that oyxtocin cannot stimulate prostaglandin F2a synthesis
How is maternal recognition of pregnancy achieved in pigs *
pigs embryos produce estradiol which re-routes PGF secretion into the uterine lumen
Pig embroys will migrate throughout the uterus on day 8-9 and spread apart.
Migration stops at day 12
A total of 4 embryos are required for MRP
At least 1 embryo has to be in each horn
How is maternal recognition of pregnancy achieved in equine
the signal is not known
What produces IFN-t
trophoblast cells of bovine and ovine embryo
What does the elongation of the bovine and ovine embryos do? **
embryo elongate in their ipsilateral uterine horn to the CL
this elongation allows IFN-t produces by trophoblast cells to contact the entire ipsilateral endometrium to signal MRP
What is required for MRP in pigs *
1) Embryo migration from days 8-12
2) Total of 4 embryos or more
3) At least 1 embryo has to be in each horn
4) Estrogens from embryos
How many embryos are needed in pigs for MRP
4 embryos
at least one in each horn
What is needed for MRP in equine
Equine embryos spherical and migrate throughout entire uterine lumen (both horns and body) multiple times each day
migration facilitates embryo signaling in the entire endometrium for MRP
important relative to the mechanism by which prostaglandins travel to the ovary in the mare (systemic circulation)
When do equine embryos stop migrating
day 16 (MRP happens 12-14 days)
twins that arise from the fertilization of two oocytes
Dizygotic twins (non-identical)
twins that arise from fertilization of one oocyte from one ovulation and the developing embryo splits
Monozygotic twins
In what species are twins or triplets common
sheep and goats
survival offspring are of economic benefit
T/F: twins survive in horses and this is economically beneficial
False- twins often do not survive in horse to term or early neonatal loss occurs
What does embryo splitting do
it creates identical twins
What is the incidence rate of embryonic loss
2-20%
Conception (fertilization) rates are
often very high
determined by the presence of cleavage stage or early developing embryos in the oviduct 2-3 days after ovulation
uterine pregnancy rates are
usually much lower that conception rates
embryos visible on ultrasound exam 14-18 days after ovulation
suggests that early embroyonic loss rates are significant
What happens when there is embryonic loss prior to maternal recognition of pregnancy
CL regresses at normal time
no delay in return to estrus
What happens when there is embryonic loss after maternal recognition of pregnancy
CL persist
Delay in return to estrus
Need to administer prostaglandins to lyse CL and allow for a return to estrus
What are causes of early pregnancy loss
1) maternal age (older oocytes, DNA damage over time)
2) Endometrial/uterine disease
3) Progesterone abnormalities
4) Chromosomal abnormalities
5) Inadequate nutrition
6) Maternal stress
7) Early postpartum pregnancies (some species)
8) Abnormalities of embryonic development
describe only the fetal component of the placenta
fetal membranes
placenta consists of
both maternal and embryonic/fetal components
How is the fetus nutritionally supported in early pregnancy
secretions from endometrial glands provide micronutrients which are taken up by the trophoblast cells and eventually by the vascularized yolk sac
-Histotrophic support
How is the fetus nutritionally supported in later pregnancy
development of close association between vascular tissue of maternal endometrium and fetal membranes allows for hemotrophic support
When does implantation/ attachment (interdigitation of placental tissue with endometrium occur)
Pigs: 14-18 days
Sheep: 15-18days
Cows: 18-22 days
Horses: 35-38 days
When does implantation/ attachment (interdigitation of placental tissue with endometrium occur) in pigs
Pigs: 14-18 days
When does implantation/ attachment (interdigitation of placental tissue with endometrium occur) in sheep
Sheep: 15-18days
When does implantation/ attachment (interdigitation of placental tissue with endometrium occur) in cows
Cows: 18-22 days
When does implantation/ attachment (interdigitation of placental tissue with endometrium occur) in horses
Horses: 35-38 days
What is the membrane that surrounds the developing fetus
amnion
what is the outpouching of the fetal hindgut
chorioallantoic membrane
What fluid is ruptured
allantoic fluid as the chorioallantois ruptures
placenta type where microcotyledons evenly spread out across entire placenta
Diffuse
horse and pig*
What kind of placenta type do horses have
Diffuse
placenta type where microcotyledons evenly spread out across entire placenta
What kind of placenta type to pigs have
Diffuse
placenta type where microcotyledons evenly spread out across entire placenta
placenta type where discrete attachment sites between cotyledons (placenta) and caruncles (uterus) forming placentomes
Cotyledonary
ruminants
What kind of placenta type do ruminants have
Cotyledonary
placenta type where discrete attachment sites between cotyledons (placenta) and caruncles (uterus) forming placentomes
What is the maternal component of the placentome
caruncles (uterus)
What is the fetal component of the placenetome
cotyledons (placenta)
placenta type where contact between placenta and endometrium is in a band around the fetus
Zonary
-carnivores
What type of placenta type do dogs have
Zonary
placenta type where contact between placenta and endometrium is in a band around the fetus
What type of placenta type do cats have
Zonary
placenta type where contact between placenta and endometrium is in a band around the fetus
What kind of placenta type do primates and rats have
discoid
How many placenta layers are there in ruminants
Epitheliochorial
-chorionic villi grows into the aperatures of uterine glands
6 degrees of separation
1) Fetal endothelial cells
2) Fetal connective tissue
3) Chorionic epithelial cells
4) Endometrial epithelial cells
5) maternal connective tissue
6) maternal endothelial cells
*present in all large animals
What does it mean when animals have an epitheliochorial placenta type
Epitheliochorial
-chorionic villi grows into the aperatures of uterine glands
6 degrees of separation
1) Fetal endothelial cells
2) Fetal connective tissue
3) Chorionic epithelial cells
4) Endometrial epithelial cells
5) maternal connective tissue
6) maternal endothelial cells
*present in all large animals
What does it mean when animals have an endotheliochorial placenta type
Endotheliochorial
-Chorionic villi are in contact with the endothelium of maternal blood vessels
-4 layers of separation
1) Fetal endothelial cells
2) Fetal connective tissue
3) Chorionic epithelial cells
4) Maternal endothelial cells
*loss of endometrial epithelial cells and maternal connective tissue
*Dog and cat
How many placenta layers do dogs and cats have
Endotheliochorial
-Chorionic villi are in contact with the endothelium of maternal blood vessels
-4 layers of separation
1) Fetal endothelial cells
2) Fetal connective tissue
3) Chorionic epithelial cells
4) Maternal endothelial cells
*loss of endometrial epithelial cells and maternal connective tissue
*Dog and cat
What does it mean when an animal has hemochorial placenta
Hemochorial
-fetal chorion comes into direct contact with maternal blood
*3 layers of separation
1) Fetal endothelial cells
2) Fetal connective tissue
3) Chorionic epithelial cells
What kind of placenta do primates and rodents have
Hemochorial
-fetal chorion comes into direct contact with maternal blood
*3 layers of separation
1) Fetal endothelial cells
2) Fetal connective tissue
3) Chorionic epithelial cells
All foals, calves, lambs, kids are born with a functional immune system but not any antibodies, why is this?
Because they have an epitheliochorial placenta (all 6 layers are intact and large IgG cannot pass)
Need to have colostrum
Why is it even more important that foals, calves, lambs, and kids get colostrum
Because they have an epitheliochorial placenta (all 6 layers are intact and large IgG cannot pass)
Need to have colostrum
What are the layers in the epitheliochorial placenta
6 degrees of separation
1) Fetal endothelial cells
2) Fetal connective tissue
3) Chorionic epithelial cells
4) Endometrial epithelial cells
5) maternal connective tissue
6) maternal endothelial cells
What are the layers of the endotheliochorial placenta
-4 layers of separation
1) Fetal endothelial cells
2) Fetal connective tissue
3) Chorionic epithelial cells
4) Maternal endothelial cells
What are the layers of the hemochorial placenta
-fetal chorion comes into direct contact with maternal blood
*3 layers of separation
1) Fetal endothelial cells
2) Fetal connective tissue
3) Chorionic epithelial cells
Rank the different placenta types by their level of transplacental transfer of immunoglobulins during pregnancy
Hemochorial > Endotheliochorial > Hemochorial
T/F: colostrum is not very important in cats and dogs because they still get some transplacental transfer of immunoglobulins
False- they have 4 layers of separation between vascualar supply of dam and vascular supply of fetus allows some transfer of immunoglobulins but colostrum is still important
What are the species that depend on the CL for progesterone throughout gestation
Dogos
Cats
Goats
Pigs
Llamas/ Alpacas
T/F: dogs are CL dependent species for their progesterone source throughout gestation
True
T/F: cats are CL dependent species for their progesterone source throughout gestation
True
T/F: goats are CL dependent species for their progesterone source throughout gestation
True
T/F: pigs are CL dependent species for their progesterone source throughout gestation
True
T/F: llamas/ alpacas are CL dependent species for their progesterone source throughout gestation
True
T/F: horses are CL dependent species for their progesterone source throughout gestation
False- they rely on their CL for 70 days out of 11 month gestation and then it switches to placenta
T/F: sheep are CL dependent species for their progesterone source throughout gestation
False- they rely on their CL for 50 days out of a 5 month gestation
T/F: cows are CL dependent species for their progesterone source throughout gestation
False- they rely on their CL for 6-8 months out of the 9month gestation
In horses, when does progesterone source switch from CL to placenta *
they rely on their CL for 70 days out of 11 month gestation and then it switches to placenta
(full switch over at 120 days)
In sheep, when does progesterone source switch from CL to placenta
they rely on their CL for 50 days out of a 5 month gestation
In cows, when does progesterone source switch from CL to placenta
they rely on their CL for 6-8 months out of the 9month gestation
What do horses form at 35 days of gestation ***
endometrial cups- cells from trophoblast invade into tissue to produce eCG
What signals the mare’s ovary to make the secondary CL *
endometrial cups (d35)- cells from trophoblast invade into tissue to produce eCG
specialized trophoblast cells - origin is chorionic girdle (visible at day 25 of gestation), invade into endometrium (days 35) to form distinct cup shaped aggregation of fetal tissue within the maternal endometrium. What is this called
Equine Endometrial Cups (know this)
Equine Endometrial Cups **
specialized trophoblast cells - origin is chorionic girdle (visible at day 25 of gestation), invade into endometrium (days 35) to form distinct cup shaped aggregation of fetal tissue within the maternal endometrium. What is this called
What do Equine Endometrial Cups produce
ecG is produced by bi-nucleated cells
may provide protection from maternal immune system
ecG has noth FSH and LH activity
but tells horse ovary to form secodnary or accessory corpora lutea
What is the result of ecG produced by the endometrial cups of the pregnant mare *
ecG has both FSH and LH activity
1) Endogenous FSH stimulates follicle development in pregnant mare
2) Causes ovulation and/or luteinization of the large follicles
3) Secondary or accessory corpora lutea form- to produce additional progesterone and helps support early pregnancy
When do endometrial cups in mare typically disappear
after 120-150 days of gestation via immune rejection (formed at day 35 of gestation)
What is the result if there is pregnancy loss after day 35 in the mare
the mare forms endometrial cups at day 35
cups will remain present; eCG production is continued and the mare is lost for the season and will not cycle back
What happens with persistent endometrial cups
continued presence beyond 150 days after pregnancy loss or after delivery of normal healthy full term foal
eCG prodiction continued
results in abnormal ovarian function
What happens to the equine fetal gonads during gestation
gonads of male and female fetus undergo dramatic enlargement and regression between 3-8 months of gestation
*enlarged gonads produce androgen precursors and those androgens can be converted to estrogens by placental aromatase
Androgen and estrogen levels increase in maternal blood- may cause behavioral changes in mare (aggressive or stallion live behavior)
What is the result of the enlarged equine fetal gonads between months 3-8 of gestation
*enlarged gonads produce androgen precursors and those androgens can be converted to estrogens by placental aromatase
Androgen and estrogen levels increase in maternal blood- may cause behavioral changes in mare (aggressive or stallion live behavior)
Trouble with equine twins
abortion rate is high
most mares cannot carry twins to term (abortion after 7months)
cause of abortion is placental insufficency
complications:
retained placenta
dystocia
ruptured prepubic tendon
rebreeding problems
What are the complications of equine twins
retained placenta
dystocia
ruptured prepubic tendon
rebreeding problems
Most have abortions after 7 months
T/F: it is okay to advise clients that they can let the mare carry both embryos to term
False- terrible idea
What should you do if you have a mare pregnant with twins*
abort embryos and rebreed
-not popular with the client
so you can eliminate one embryo- pregnancy reduction (most common procedure)
When is the best time for pregnancy reduction in a mare with twins
Day 14-16
Embryos migrate throughout uterus from day 6 to day 16, at which time they fix in position
Reduction is when one embryonic vesicle is disrupted and the other is allowed to continue to develop
Do you chose to reduce the smaller or larger embryo when a mare has twin embryos
smaller
How is twin reduction done in mares
1) around day 14-16 when the embryos are migrating throughout the uterus
2) Press down with ultrasound and steam roll to disrupt the membrane around the embryo
What is the optimal technique for pregnancy diagnosis
*Stage dependent
False negatives and positives are possible with any test
T/F: false negatives and positives are possible with any pregnancy diagnosis test
True
What are the different pregnancy tests for the mare
1) Early Pregnancy Factor (HSP-10) - day 1-120 of gestation
2) U/S: day 11- term
3) Palpation: day 18- term
4) Progesterone: day 18-90
5) eCG: day 35-120
6) Relaxin: day 80-term
7) Estrogens (conjugated or total- day 90 to term)
How might you behavior play a role in pregnancy diagnosis
potentially effective only in polyestrous species (large animals with repeated estrous cycles)
Failure to return to estrus may be suggestive of pregnancy, however other reasons exist for failure to return
expression of estrus strongly suggests that not being pregnant, however this may be erroneous
expression of estrus strongly suggests ____________, however this may be erroneous
expression of estrus strongly suggests that not being pregnant, however this may be erroneous
What might be potential causes of errors for using behavior in polyestrous species for pregnancy diagnosis
inappropiate heat detection
season
lactation
nutrition
pseudopregnancy (persistent CL)
early embryonic loss
failure of follicular developement
ovarian patholgoy (ie ovarian cysts)
visual assessment of abdomen for pregnancy diagnosis
potentiall effective in second to third trimester of many pregnany animals
changes in abdominal shape and body weight may be indicative of pregnancy
may be difficult in overweight or obese animals
When might external palpation of the abdomen for pregnancy diagnosis be effective in dogs
days 24-35 of gestation
feel a string of pearls
Palpation of abdomen for pregnancy diagnosis
Dog: days 24-35 of gestation
feel a string of pearls
Large animals: ballottement of the abdomen (large animals)- bump fetus on transabdominal pressure, detection of fetal movement
Common technique to detect pregnancy in large animals (cows and horses)
inexpensive, rapid accurate
stage dependent and require practiced clinical skil
often performed in conjunction with U/S in horses
transrectal palpation
What are the 4 positive signs of pregnancy in cattle when doing transrectal palpation *
1) Palpation of the amnionic vesicle
2) Fetal membrane slip
3) Palpation of the placetome (cotyledon/caruncle)
4) Palpation of the fetus
*Fremitus in middle uterine artery- fluid turbulence associated with a buzz feeling is “suggestuve of pregnancy but not a + sign)
What sign on transrectal palpation in cattle is suggestive of pregnancy but not a + sign
*Fremitus in middle uterine artery- fluid turbulence associated with a buzz feeling is “suggestuve of pregnancy but not a + sign)
only detectable in pregnant animal but not direct diagnosis
Palpation of the amnionic vesicle *
*one of the 4 signs of transrectal palpation in the cow
-retract reproductive tract into the pelvic canal
-fell uterus for asymmetry
*can estimate the day of gestation
know these two things
What is the membrane slip
one of the 4 signs of pregnancy in cattle when doing transrectal palpation
*Chorioallantoic membrane between placentomes
What are you feeling on a membrane slip
Chorioallantoic membrane between placentomes
Palpation of placentome
one of the 4 cardinal signs of pregnancy diagnosis via transrectal palpation
feeling for the caruncle/ cotyledons
*Size of placetome can be used to estimate gestational age
example 75 days- pea size and increase to half dollar size (150 days)
When can you first palpate the fetus in cows
one of the 4 signs of positive pregnancy in cattle via transrectal palpation
55-60 days
estimate size (2 months- mouse and increase to beagle dog at 6 months)
What are the 4 positive signs of pregnancy in cattle when doing transrectal palpation *
1) Palpation of the amnionic vesicle
2) Fetal membrane slip
3) Palpation of the placetome (cotyledon/caruncle)
4) Palpation of the fetus
What are the positive signs of pregnancy in horses when doing transrectal palpation *
1) Fetal bulge (size dependent on stage of gestation)
2) Fetal movement
*NO membrane slip (diffuse placenta)
*No placetomes (diffuse placenta)
Additional signs: increase tone in uterus and cervix
Why might you need to do U/S with transrectal palpation for pregnancy diagnosis in the horse
*NO membrane slip (diffuse placenta)
*No placetomes (diffuse placenta)
transrectally, can only use fetal bulge and movement to detect (positive signs) and increased tone in uterus and cervix (additional sign)
When in pregnancy can amnionic vesicles first be detected in dogs on U/S
Day 19-20
When can the fetal heart beats be noted on U/S in the dog
Day 23-28+
Ultrasonography for pregnancy diagnosis in dogs
Very good for detection of pregnancy, may not be accurate for determining the number of embryos or fetuses
Transabdominal technique
Day 19-20: Amniotic vesicles
Day 23-28: heart beat can be noted (dogs)
How is ultrasounography for large animals done
transrectal technique
very good for early detection of pregnancy
Ultrasonography for pregnancy diagnosis in mares
Transrectal Approach
very good for early detection of pregnancy
Day 11- embryos first detected
Day 25- heart beat can be noted
Tell you pregnancy loss, detection and management of twins, fetal sex determination
When can sex of cattle and horse be determined
59-70 days after ovulation
*Look at the position of the genital tubercle identified
Why is radiography not good for early detection of pregnancy in small animals
it depends on mineralization of fetal skeleton (day 43-44 in dogs)
When does mineralization of fetal skeleton occur in dogs and you can therefore determine of radiography
day 43-44
How can you tell how many fetuses a dog has on radiography
count the number of skulls and spinal columns
this is good for evaluation of a bitch with dystocia
T/F: progesterone can differentiate between pregnant and non-pregnant dogs
False
What endocrine test should you use for pregnancy diagnosis in small animals
Relaxin at the second half of pregnancy
Withness Preg Test
Endocrine tests for the diagnosis of pregnancy in cattle
1) Progesterone (not direct indicator of pregnancy- complete absence of progesterone <1.0ng/ml) is compatible with pregnancy
2) Estrone sulfate - produced by placentra
3) Interferon-tau - secreted by trophoblast cells, detectable as early as 15 days after breeding
4) Early Pregnancy Factor (EPF)- detectable as early as 24 hours after ovulation
*Not usually done in cattle
T/F: progesterone is a direct indicator of pregnancy in cattle
False
Progesterone (not direct indicator of pregnancy- complete absence of progesterone <1.0ng/ml) is incompatible with pregnancy
What are endocrine tests for pregnancy diagnosis in mares
1) Progesterone- not direct indicator of pregnancy, false errors with sample timine, pseudopregnancy, complete abscence of progesterone is incompative with pregnancy
2) Early Pregnancy Factor
3) eCG- endometrial cups of placenta
4) Estrogens (estrone sulfate)
5) Relaxin
When do estrogens increase during mare pregnancy
Day 90, peak at day 200 and decrease after.
a good marker of good pregnancy health
When does relaxin begin to increase in pregnancy of mare
Day 75 increase with peak at day 150 and remains high until term
Fibrinogen and ceruloplasmin
acute phase proteins that may be elevated in dogs gestation from week 3/4 onward
can be used for pregnancy diagnosis
early pregnancy factor
elevated within a day of conception
and can be used in different species
difficult to perform
phocomelia
developed due to human mothers being prescribed thalidomide for nausea in the 1950s and 1960s
Developmental pathology is an interaction between
Genetics and Environment
What are broad classes of Environmental Teratogens
1) Physical- intrauterine trauma (e.g palpation), hyperthermia
2) Nutritional- Vit A: both hyper and hypo are teratogenic, copper deficiency, iodine deficiency
3) Toxic; plants, drugs, alcohol
4) Infectious
5) Metabolic
What is the leading cause of noninfectious blindness in the world
Hypovitaminosis A
(also hypervitaminosis A can cause teratogens)
Griseofulvin treatment of pregnant animal results in
birth defects
What does iodine deficiency lead to in neonates
Goiter
T/F: a single agent can induce dramatically different disease at different stages of gestation
True
preimplantation- early embroynic death, looks like fertility
organogenesis- major tetraogenesis
histogenesis- less severe defects
What causes cerebellar hypoplasia
Cats- Panleukopenia
Cows- BVDV or Blue tongue
What causes cerebellar hypoplasia
Feline panleukopenia
BVDV or blue tongue
Veratrum californicum
Called Skunk Cabbage
Cyclopamine (alkaloid) will produce cyclopean lambs around day 14 of gestation
causes short legged animals day 28-31
causes tracheal stenosis Days 30-36
When does feeding Veratrum californicum cause short legs and musculoskeletal abnormalities
Days 28-31
When does feeding Veratrum californicum cause cyclopean lambs?
Day 14 of gestation
When does feeding Veratrum californicum cause tracheal stenosis
Days 30-36
T/F: totally different agents can induce the same pathologic changes in the fetus
true- depends on the time of gestation
What causes Arthrogryposis
1) Heritable in several breeds of cattle and humans
2) Viral (Akabane, Cache Valley)
3) Poisonous plants (Lupine and acorn)
How do you tell if the defect is genetic or environmental
can be difficult
-Hints of mendelian or familial disease?
-Gross and histopathology of fetus, placenta
-Isolate etiologic agent
-Specific antibodies in fetal/ neonatal serum
-Examine environment (plants)
Most important is to know the possibilities
What are the factors involved in pathogenesis of tetragens
1) Genotype of animal (mother and conceptus)
2) Dose and frequency (thresholds) of tetragen
3) Nature of agent or insult (MLV vaccines)
4) Stage of development- germ cells, early embryo (usually death of conceptus) , organogenesis (major defects), histogenesis (less severe defects), perinatal period
What are the fates of abnormal conceptus
-Early embryonic death
-abortion
-mummification
-maceration
-premature birth
-still birth
-prolonged gesation
-congnenital disease
-defects manifest later in life (fetal origins of adult disease)
Why might there be prolonged gestation
adrenal hypoplasia
hypopthalamic pituitary hyoplasia
What is maceration
macerated fetal tissues - broken down a fetus with bones
where there is no evidence that a particular structure formed
Agenesis
body part is underdeveloped
hypoplasia
structure is developed but not developed correctly,
dysplasia
organ that develops but does not develop to correctly to meet its function
dystrophy
organ develops to be large
hyperplasia
where a canal is not formed in a hollow organ
atresia or stenosis
a situation in which an organ or body part is in the wrong position, either from birth or because of an injury
ectopia
where there is more than one, or the normal amount of an organ or structure
supernumeration
Ectopia cordis
where the heart develops in the wrong place
What are causes of viral teratology
-Venezuelan Encephalitis
-Rift Valley Fever
-Cache Valleu
-Bluetongue virus
-Akabane, Schmallenberg
-BVDV
-Border Disease Virus
How is bluetongue transmitted
via culicoides gnats
What teratogenic effects does bluetongue virus cause
Hydranencephaly
Bluetongue in sheep is _________ while in cattle it is_______
sheep- see severe disease, large outbreaks
Cattle- typically subclinical
Why should you not vaccinate pregnant animals for Bluetongue
attenuated vaccines can cross the placenta and cause hydranencephaly (destructive process)
How is Akabane transmitted
it is a bunyavirus that is transmitted by mosquitoes and Culicoides
Akabane virus
bunyavirus that is transmitted by mosquitoes and Culicoides
distribution: Australia, Japan, Africa, Israel
infected adult cattle, sheep, and goats (subclinical)
lesion: abortion, stillbirth, premature birth, arthrogryposis and hydranencephaly
How does Akabane virus affect pregnancy?
Abortion, stillbirth, and premature birth
*Arthrogyposis and hydraencephaly of the fetus
What lesions to the fetus will you see with Akabane virus
Abortion, stillbirth, and premature birth
*Arthrogyposis and hydraencephaly of the fetus
Schmallenberg virus is a _____________
bunyavirus in Europe, discovered 2011
vector borne
-hydraencephaly
-arthrogyrposis
(similar to Akabane)
Cache Valley virus is a ___________
mosquito borne bunya virus
mild in adults but in pregnancy
<32 days- conceptus death
32-37 days- Musculoskeletal/CNS
38-48 days- mostly CNS
>48 days- few affects if any
Hydraencephalic calves can be caused by Bluetongue, Akabane, or Schmallenberg. How do you differentiate??
Akabane and Schmallenberg is foreign so alarming
Differentiate via testing for antibodies.
When do calfs gain immunocompensy in gestation
around day 150. will produce antibodies against the virus if exposed in utero
Noncytopathogenic viruses
infection 60-120 days
widespread fetal infection but not aborted
persistently infected -> families
Status at birth:
Virus positive
antibody negative
Cytopathogenic viruses
infection throughout gestation
critical periods: death to no significant effect
Status at birth: Virus negative and antibody positive
When does non-cytopathogenic BVDV infection occur
60-120, widespread fetal infection (not destroyed because occurs before immunocompensy and see it as sell)
not aborted
stays in the family
Noncytopathogenic is virus _____ and antibody _____ while cytopathogenic is virus ____ and antibody ____
Noncytopathogenic: Virus positive, antibody negative
Cytopathogenic: virus negative, antibody positive
Border Disease virus
a pestivirus in sheep
lesions:
1) dysmyelination (shaker)
2) wool looks like hair (hairy)
Hairy Shaker Disease
What are the two lesions seen with Border Disease Virus
1) Dysmyelination (Shaker)
2) Wool looks like hair (Hair)
Hairy Shaker Disease
Pestiviruses
1) BDVD
2) Swine Fever Virus
3) Border Disease Virus
derived from trophoblastic ectoderm and extraembryonic mesoderm
chorion
How does the chorion form
derived from trophoblastic ectoderm and extraembryonic mesoderm
mesodermal bud emerging from the posterior end of the primitive streak. The bud grows and expands across the exocoelomic cavity and fuses with the chorion
allantois
What are the functions of the placenta
1) Exchange between mother and fetus- massive surface area, large blood flow. gases and small molecules like gluocse
proteins: limited if any transport can pass (IgG in some species)
Toxins
2) Endocrine functions: significant species differences
Progesterone- all mammals but different quantitity
Estrogens
Gonadotropin -eCG or hCG
