Therio- Bovine- pregnancy 1

untimely's version from 2015-08-29 20:39


Question Answer
where does fertilization occur?ampulla of the uterine tube
where does Capacitation start? where does it end?begins in the uterine horn, and ends in the uterine tube
how do non-motile sperm get culled?they can't get past the cervix
what is capacitation?Sperm have to undergo capacitation before they are capable of fertilization (it is the first step). It involves the destabilisation of the acrosomal sperm head membrane allowing greater binding between sperm and oocyte--> this is done by seminal plasma coatings being released along with some surface proteins. There is also Reorganization of surface receptors so that sperm can bind to zona pellucida (ZP)
Before fertilization can occur, Spermatozoa need to undergo what 3 things?in order: (1) Capacitation (2) Hypermotility (3) Acrosome reaction
why does frozen semen have such a short half life?Frozen semen once thawed is already capacitated! This cuts down on the half life
where do sperm become hypermotile?in the uterine tube
when does the Acrosome Reaction occur, and what happens during the reaction?Initiated by binding to the zona pellucida of the oocyte. Causes fusion of the spermatozoal plasma membrane & the outer acrosomal membrane (the outer plasma membrane of the sperm and the one below it which is the outer acrosomal membrane), which Exposes enzymatic vesicles (of acrosin hyaluronidase) which allow spermatozoon to tunnel (digest) through Zona pellucida
what happens after the sperm start to tunnel through the zona pellucida? (end with when a zygote forms)Fusion of oocyte & sperm plasma membranes, which then causes a Vitelline block and a zona block (prevents polyspermy), and then Sperm is engulfed into oocyte cytoplasm where there is Fusion of male & female pronuclei to form a zygote
how is fetilization by more than one sperm prevented?Vitelline block and a zona block (caused by fusion of oocyte and sperm plasma membranes)
how does the vitelline block work?Reduces the ability of the oocyte plasma membrane from fusing with additional spermatozoa
how does the zona block work?ZP undergoes biochemical change so that no other sperm can bind
What is superfecundation?The phenomenon whereby spermatozoa from multiple males can fertilize multiple oocytes (Can occur in dogs due to the sustained fertile period & multiple ovulations.)
what is a Zygote?formed after fusion of male & female pronuclei
embryo vs fetusEMBRYO: what zygote becomes after first division of cells upto D42 of gestation. FETUS: from D42 of gestation when embryo become more recognizable
what is Conceptus?the products of conception; often used interchangeably with embryo


Question Answer
how does maternal recognition of pregnancy in the cow happen? (2 ways) when does it happen? why is this important?(1) Secretion of IFN-τ (tau) by the conceptus (2) Rapid outgrowth of the trophoblast to contact all parts of the endometrium. <-- both of these occur by D15-16. This Prevents luteolysis & resumption of cyclicity to maintain the preg
*Duration of pregnancy in cattle?9mo (280 d)
how does the fetal gender affect duration of preg?females cause a longer duration of preg than males
how does singles vs mults of fetii affect duration of preg?singles take longer than multiples (mults take up more space-- get cramped sooner-- trigger preg sooner)
how does breed affect duration of preg?Bos indicus take longer than Bos taurus (possible size reason?)
how does nutrition affect duration of preg?undernutrition= shorter gestation
what must you use to induce abortion during the first part of preg (up to D150) (must know what structure is involved in maintainance)ONLY primary CL is maintaining preg, so you can just use injection of PGF2a
what must you use to induce abortion during the middle part of preg (D 150-250) (must know what structure is involved in maintainance)BOTH the primary CL and the PLACENTA are maintaining preg, so you need to do PGF2a as well as Dexamethasone
what must you use to induce abortion during the last part of preg (D 250-280) (must know what structure is involved in maintainance)ONLY primary CL is maintaining preg (placenta only does so from d150-250) so you can use PGF2a, OR Dexamethasone OR combination
what are 3 reasons you might want to To treat misalliance or induce abortion during pregnancy?(1) Misalliance (eg. Neighbour’s bull got into your heifers…) (2) Life threatening illness to dam (eg. Hydroallantois, pregnancy toxemia) (3) prolonged gestation
Induction of abortion >4 months of gestation and induction of partus may result in what problems?RFM (retained fetal membranes) and metritis
what is the classification of Distribution of chorionic villi of the placenta of cows?Cotyledonary (also, according to a diagram, the caruncular tissue invades into the chorionic tissue in cows. It's vice versa in other animals)
what is the classification of Layers separating fetal & maternal blood of the placenta of the cow?Syndesmochorial (the epithelium of the maternal tissues is eroded to facilitate intercommunication) (sometimes classified as epitheliochorial because the maternal layer is only partially eroded)
what is syndesmochorial?Epitheliochorial placenta where endometrial epithelium transiently erodes and regrows, exposing maternal capillaries to chorionic epitelium. Maternal capillaries are Also exposed to Binucleate giant cells in the trophoblast epithelium (fetal membranes) that secrete placental lactogen and pregnancy specific protein B
******SLIDE 32-- KNOW THIS PICTURE AND BE ABLE TO LABEL IT (1) amnion (2) Allantois (3) chorion (4) yolk sac (5) caruncle (6) allantochorion (7) Allantoamnion (8) Amniochorion (9) Umbilical cord
(FYU) whats the Chorionouter layer in contact with maternal endometrium
(FYU) whats the Allantois?space that is enclosed by the chorion, but outside of the amnion
(FYU) whats the Amnion?the innermost membrane that encloses the embryo
why do you want to detect preg as early as possible, and what are 3 ways to do so?do to avoid economic loss. (1) Rectal palpation (2) Ultrasonography (3) Progesterone concentrations in milk/blood
rectal palpation is the most commonly used way to detect preg. When is it most effective? (most basic steps to it?)>95% accurate if >6wks (42 days) + experienced operator. (Locate the cervix, Retract the uterus into pelvis, gently palpate)
from rectal palpation, what are 4 definitive signs of preg?Membrane slip, Amniotic vesicle, Fetus present, Placentomes present
what's a Placentome?maternal caruncle + fetal cotyledon
when do you do a membrane slip and what is it exactly?Between D 30 and end of gestation. the whole thickness of the horn is carefully slipped between the index finger and thumb, feeling the allantochorionic membrane slip (false positive if uterine horn and broad ligament are grasped)
when do you palpate for the Amniotic vesicle? how do you do this?Palpable between D 30 and 65, after that too soft and too large. The amniotic vesicle is gently surrounded by placing all four fingers dorsally and the thumb ventrally along the greater curvature of the horn. Egg shaped mobile structure that Feels like a bar of Soap slipping through Your hand
When do you determine preg by Palpation and ballotment of the fetus?From D65 (~2mo) to 4.5 mnths, and then after 6m-- **Between 4.5 mnths - 6 mnths, the foetus CANNOT be felt; BUT feel the tension on the cervix, fremitus and placentomes
how do you perform a ballotment of the fetus?(remember, from 2-4.5mo, then after 6mo) put the palpating hand on the dorsal wall of the uterus and make a patting movement, the foetus is felt when it rebounds against the hand in response to that movement
when can you start to feel placentomes? How?can be felt from D 70 (2.5mo) and get larger with time- stroke flat hand over uterine surface the thickenings of the uterine wall can be felt
well developed CL is suggestive or definitive for preg? How would you describe this?SUGGESTIVE--> a cow with a CL at 21d after breeding, a diestrous tone and no large follicle is most likely to be pregnant.
where does the CL usually lie in relation to the preg horn?ipsilateral
if the cow is preg, and you palpate a follicle on the ovary, what do you think?normal-- FSH still secreted during preg (not suppressed by progesterone)
is asymmetry of the uterine horns suggestive or definitive for preg? why does this occur?SUGGESTIVE--> due to accumulation of fluid in the pregnant horn, but not definitive bc can also be present in prepubertal cows or cows that recently aborted
if you palpate Fluctuations of one or both uterine horns, what do you think this means? it is very suggestive of preg, starting at around D30(1mo). The uterus is relaxed and thin walled due to progesterone,and the feeling is most apparent at the tip of the horn. (CAUTION: consider pyometra, mucometra, hydrometra, etc)
explain Fremitus of the uterine artery--> is this suggestive or definitive? what is it?suggestive! characteristic type of vibration which can be felt when the artery is slightly compressed between the thumb and a finger (Feels like sand grains rushing through the blood vessel)
*when can you feel fremitus of the uterine artery?3.5mo on the preg side. and then 5mo on the non-preg side (twins from 3.5m on both sides) (she skipped this slide, but, to find uterine aa: In the mesometrium in the lateral aspect of the cranial part of the pelvis, within a few cm of the external iliac artery. external iliac is fixed to the ilium, uterine artery is freely mobile)
what are two signs BEFORE d70 (2.5mo) of preg that are DEFINITIVE?(1) positive membrane slip (2) Presence of an amniotic vesicle
what are two signs AFTER d70 (2.5mo) of preg that are DEFINITIVE?(1) palpate fetus or parts of it (2) feel placentomes
when can you feel membrane slip?30d (1mo)
when can you feel amniotic vesicle?D30-D65 (1mo-2.5mo)
when can you feel the fetus?D65-4.5 months (2.5mo-4.5mo) (and then 6mo)
when can you feel the placentomes?d70 (2.5mo)
explain in order from earliest sign to fetus, what you can palpate in the preg cowMembrane slip--> amniotic vesicle--> fetus (until 4.5mo)--> placentomes--> fremitus on preg side--> fremitus on non-preg side--> fetus (after 6mo and to term)
early embryonal death is a risk factor with rectal palpation, esp if before day ___ or handled roughly. So after palpation you should recheck at ___(time)(1) before d50 (1.5mo) (2) 3-4m
what's pluriparous?Producing several young at a single birth.
give some examples of stuff that can cause a false pos of pregpluriparous cow with a large uterus, cow 4,5-6m pregnant (this is false negative), cow in early puerperium (calved 2-3wks ago) or recently aborted, cow with delayed uterine involution, pyometra/mucometra, distended urinary bladder, gas filled colon loops or caecum, firm masses like abscesses, tumours, bones of macerated foetuses or a mummified foetus
when can you dx preg by Ultrasonography at the earliest? what do you see? (universal for all sp!)From D25-- heartbeat visible
when can you see the heartbeat with ultrasonography? placentomes? Ribs?heart d25, placentomes d33-38, Ribs d50-55
WHEN can you determine fetal sex via ultrasonography? and HOW?between d55-60 (after you can see ribs). in MALE the genital Tubercle moves towards the umbilicus, and in FEMALES the Tubercle moves towards the tail
if the genital tubercle moves towards the umbilicus, is it male or female?MALE (female is toward the tail)
when is [Progesterone]milk/serum looked at? is this test better for determining if theyre preg or not preg?Performed on D21 after insemination (should have elevated [progesterone] if pregnant and basal [progesterone] if not pregnant). 100% accurate to confirm non-pregnant (high specificity), but 85% accurate to confirm pregnancy (lower sensitivity)
what are some reasons you might get a false positive P4 (milk or serum) test? (high progesterone but not preg)samples taken at the wrong time (<d19 or >d21 after AI), Poor management (AI at wrong time, or AI date recorded wrong), animal has had a shortened dioestrous period (endometritis), or prolonged dioestrous period due to retained CL, luteal cysts, pyometra, endometritis or EED
what is bovine Pregnancy specific Protein B (bPSPB), and what can you use it for (when?)protein secreted by the binucleate giant cells of the fetal trophoblastic epithelium... you can start to detect this around day 24.

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