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DVM 2 - 2 > Repro 3 > Flashcards

Repro 3 Flashcards

1
Q

define the placenta and what consists of

A 
any site of contact between embryonic and maternal tissues that allows for exchange of materials between the two
Consists of:
- maternal endometrium
- extra-embryonic foetal membranes:
	•allantois
	•chorion
	•Amnion
	•(yolk sac)
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2
Q

Amnion what made up of, function and what is the special feature in ruminants

A

made up of trophoblast and embryonic mesoderm; chorioamniotic folds expand dorsally and fuse over embryo -> creating the chorioamniotic raphe/mesamnion; the amniotic cavity is filled with amniotic fluid, which protects the embryo/foetus from any impacts and provides the foetus with an environment in which it can move its limb and body;

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3
Q

chorioamniotic raphe/mesamnion what is it, what species present in and its function

A
  • Not present in horses just a ruminant and pig thing
  • Attachment between the amnion and chorion
  • Anchors the embryonic cavity to one spot
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4
Q

Allantois what is it, what does it fill with and what does it combine with to form

A

diverticulum of the hindgut; fills with foetal waste fluids; grows in between amnion and chorion (if growing completely around -> loss of mesamnion); allantoic mesoderm fuses with the mesoderm of the chorion -> forming the allantochorion; allantois is vacularized by allantoic arteries (branches of aorta) -> allantoic veins (umbilical veins) enter the foetus via the umbilicus (review foetal circulation)

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5
Q

what occurs in terms of nutrients before placenta is formed and after, does the maternal blood come into contact with the foetal

A

Before placenta is formed nutrients -> are provided by the endometrial glands (histotrophe- uterine milk)
Once placenta is formed nutrients -> is supplied by the haemotroph nutrition (essential metabolites are provided by the maternal circulatory system
- BUT AT NO POINT does the maternal blood come into contact with foetal blood

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6
Q

what are the 2 main functions of the placenta

A

1) Exchange of gas and nutrients between dam and foetus, foetal waste removal
2) vital endocrine organ!
○ In some species it is the sole source for pregnancy maintaining progestogens in later gestation

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7
Q

What are the 4 main types of barriers separating maternal from foetal circulation

A

1) Epitheliochorial - all 6 layers retained, found in sow and mare
2) Endotheliochorial - endothelium directly on chorionic epithelium of the foetus, carnivores
3) Hemochorial - lose the endothelium so the blood vessels are free within and contacting the chorionic epithelium
- This is why you see blood when giving birth in humans
NO BLOOD IN DOMESTIC ANIMALS IN NORMAL BIRTH
4) Synepitheliochorial - migration of trophectodermal binucleate cells into the maternal epithelium, ruminants

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8
Q

contact surface of the placenta why is it different in different animals

A
  • The more layers between foetus and dam the bigger the surface area has to be!
    ○ (epitheliochorial -> synepitheliochorial -> endothelialchorial -> haematochorial)
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9
Q

Type of placentation in horses/pigs, ruminants, dogs and cats and primates

A

Horse - diffuse - diffuse distrubution of villi
Ruminants - Cotyledonary - caruncles
Dogs and cats - zonary - band - only attach on the band
Primates - discoid - small area

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10
Q

what are the 3 configuration of chorionic attachment to the maternal epithelium

A
  1. Folded- folds & troughs, rugae & fossae
  2. Villous- chorionic villi & endometrial crypts & septa
  3. Labyrinthine- chorionic villi or lamellae
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11
Q

What are the 3 different degrees of invasiveness (is maternal tissue lost when foetus is

A

1) Deciduate: maternal tissue is lost when placenta is discontinued (endothelialchorial, haemochorial)
○ Primates, humans and dogs
2) Non-deciduate (adeciduate): maternal tissue is NOT lost when placenta is discontinued (epithliochorial)
3) Partial-deciduate: due to fusion of the epithelial -> partial

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12
Q

Cotyledon and placentome what are they and what animals present in

A

Cotyledon:
- Form were trophoblast is in touch with caruncle
- consists of abundant blood vessels and connective tissue
Placentome:
- placental unit; consists of foetal cotyledon and maternal caruncle
○ Caruncle -> determine where the cotyledons are formed
§ Have some redundancy and is formed by the maternal endometrium
- cattle: 70-120; sheep: 80-100
Foetal cotyledon
- Within the caruncle in the sheep
Outside of the caruncle in the cow

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13
Q

What time does attachment to caruncles of uterus starts, and when well established

A
  • Attachment to caruncles of uterus is initiated at day 16 (sheep)/ 25 (cattle)
  • Attachment well established at day 30 (sheep)/ 40 (cattle)
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14
Q

what makes a synepitheliochorial placenta and what species present in

A
  • Complete intact layer of epithelium in both the maternal and fetal components
    ○ However, in sheep and goats the endometrial epithelium transiently erodes and then regrows -> intermittent exposure of maternal capillaries to chorionic epithelium -> therefore classified as synepitheliochorial or syndesmochorial
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15
Q

Binucleate giant cells when appear in cow, where originate from and what is their function

A
  • Appear ~14 days in sheep and between day 18 and 20 in the cow
  • Originate from trophoblast cells and invade endometrial epithelium; constitute ~20% of bovine placenta
  • Transfer complex molecules between fetus and dam; secretory component: proteins, estrogen and progesterone
    ○ Can take up haemoglobins
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16
Q

Cattle when does amniogenesis occur, allantois and mesaminion and is yolk sac present

A
  • Amniogenesis occurs between days 13 and 16
  • The allantois starts to form between second and third week of gestation; fills the extra-embryonic coelom by the fourth week
  • Mesamnion present: attachment zone between amnion and chorion
  • Yolk sac is only functional for a short period and degenerates
    ○ Can’t see at term in the ruminants
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17
Q

Amniotic plaques what are they, where found and possible causes

A 
- Amniotic plaques (mineral deposits) are found on amniotic ectoderm around umbilical stalk
Causes:
Hyperkeratinisation of the amnion 
- Incidental finding 
May be caused by rubbing or calcium
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18
Q

urachus where run, from where and function

A
  • All animals in the embryonic stage, runs between the 2 umbilical arteries
  • From Apex of the bladder though the umbilical cord, where it runs parallel to the blood vessels and empties into the allantois
    Shunted from the urethra -> some through urethra to the amnion
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19
Q

what is the chorionic girdle and what animal present in

A

Chorionic girdle - only in horse

  • Located around the embryo
  • made up of invasive, binucleate trophoblast (foetal cells that invade the endometrium)
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20
Q

What is meant by diffuse, villous, microcotyledonary in the horse, when start to occur, area between villi what called and what occurs at day 35

A
  • Microscopally diffuse regions at foetal-maternal interface of chorionic villi-> foetal chorion interdigitates with maternal endometrium -> larger surface of attachment and not as much redundancy so need proper placenta to get full forming calf
  • Distributed over entire surface of the chorioallantois
  • Start to interdigitate: day ~35 -> when placenta really starts forming
  • Areas in between villi are called arcades
  • At day 35 trophoblast cells have divided into invasive and non-invasive components
    ○ Important day in pregnancy
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21
Q

Endometrial cups/glands what species in, what do they produce, function and what is the most important feature about them

A
  • Produce equine chorionic Gonadotropins (ecG) -> aid in recruitment, development, and luteinization of additional follicles (won’t ovulate but will start making progesterone -> instead of one CL get lots of CL’s (secondary/accessory CL’s)
    § Ovaries will be palpably larger -> between day 60-120
  • Once formed independent of the embryo so if lose embryo then will not cycle again until regresses after day 120
  • ecG production peaks between 60 and 80 days; declines thereafter and is gone by 120 days
    Are attacked by the maternal immune response at this point -> push out of endometrium and into the membrane
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22
Q

yolk sac which animal is it seen grossly

A

The yolk sac in the horse remains relatively large and can be seen as a remnant at term

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23
Q

Equine Placentogenesis when does fixation occur, aminiogenesis and allantois

A
  • Day 16-17 -> FIXATION OF THE EMBRYO to the base of the horn
  • Amniogenesis occurs between day 17 and day 22
  • The allantois starts to form around day 22 is vascularized by day 25
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24
Q

Umbilical cord what are the 2 parts and where does it run

A
  • Intra amniotic - where urachus runs through the amniotic cavity
  • Extra amniotic cord - outside the amniotic cavity where empties into allantois
  • Runs from the umbilicus of the foetus crosses the amniotic cavity and ends at the boundary of the amnion
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25
Q

what is the difference in membranes at birth with horses and cattle

A

Horses -> head first and see the amnion
- Amnion acts as lubrication
○ Can suffocate within the amnion
Chorion allantois breaks first -> water breaking
Cattle -> feet first - mesamnion -> holding the amnion back in the uterus

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26
Q

Hippomanes what species present in and what are they

A
  • Amorphous, khaki-brown colored lumps
  • Formed from fetal waste products
  • Incidental finding
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27
Q

porcine placenta when does chorionic folds form, when is placenta established, what occurs with litter membranes and the tips

A
  • First chorionic folds around fourth week -> know the ball park figures not individual figures - AROUND 3 - 4 WEEKS
  • Apposition to endometrium well established from fifth week (epitheliochorial)
  • Several foetal membranes of neighbouring foetuses may fuse -> as litter species so little room within
  • Tips of Chorioallantois remain free and become necrotic (it out grows the embryos blood supply)
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28
Q

Areolae what species, what are they, when form, function

A

PIGS

  • Small, round, grey, thickened foci on Chorion
  • Formation starts in second month of gestation
  • Focal accumulations of secretory gland products (histiotroph - similar to arcades in horses
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29
Q

placentation in carnivore what does it look like

A
  • Zonary placenta (: attachment of chorion epithelium with maternal endothelium in a broad band
  • Highly convoluted chorionic villi fuse and form chorionic cords next to the maternal endothelium
    => labyrinthine organization
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30
Q

What are the 3 things a difference in placentation can lead to

A
  1. Transfer of Immunoglobulins
  2. Susceptibility to pregnancy loss due to luteolysis
  3. Puerperium - the time after birth when animals can fall pregnant again
    ○ Dog 120 days -> independent on whether pregnant or not (as always thinks its pregnant)
    ○ Horses -> once foetal membranes removed don’t have issues -> 10 days after birth
    § Depends on the remodelling that needs to occur
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31
Q

What are the 2 main source of progestagens for the equine and the sequence of events

A

Uterine progesterone
1. The primary CL is the main progesterone horse in the equine pregnancy until about day 40 of gestation
2. The weight of the embryonic cups increases rapidly over the first 3 weeks
3. The production of ecG (produced by the cups) is closely related to the weight of the endometrial cups
4. ecG initially stimulates the primary CL to produce more progesterone
○ ecG is LH-like there results in luteinization of the follicles
○ FSH-like action in other species
5. High circulatory ecG concentrations then lead to the luteinisation of more follicles resulting in accessory CL
○ At this point the pregnancy is considered more safe
6. After day 100 the placenta takes over the role for the main production of progestagens

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32
Q

when the placenta takes over the role of making progesterones what is mainly produced

A

○ Now considered placental progesterone -> not actually high at this point
○ Equine placenta progestagens -> 5-alpa pregnanes -> main production from the placenta
THEREFORE total progestagens is measured not just progesterone as they will be low while total is high

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33
Q

what is the issue until the point the placenta takes over in the animals and what is special about the horse

A

Until the point the placenta takes over vulnerable to progesterone causing luteolysis -> only need one shot of progesterone to induce abortion
Equine after day 60 has accessory CL as a safeguard so would need to give more than one shot to induce abortion

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34
Q

At what point in the horse does termination of pregnancy not result in return to oestrus and what can prolong this

A
  • Termination of pregnancy >34 to 37 days gestation (induced or natural) may not result in return to oestrus
  • Persistence of endometrial cups may delay return to regular cycles for 3 to 4 months (the cups continue to function and produce eCG; they survive until the time of their normal demise)
    ○ No foal heat and doesn’t come back into heat
    ○ Diagnosing -> hysteroscopy
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35
Q

what occurs with pigs, cats, dogs and sheep with placental take over of production of progesterones

A

Pigs, cats, dog
- Never placental take over for the production of progesterone
○ Some progestagens produced by the placenta but not complete take over
Sheep
- After 1/3rd of the pregnancy the placenta will take over (day 50d)
Cattle
- After 6-8 months placenta will take over
- Will still have a CL

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36
Q

what is special about goats in terms of placental take over of production of progestagens

A
  • Rely solely on their ovulatory CL for their whole gestation
    ○ Of give single shot of progesterone at pregnancy then will lose the pregnancy -> leads to luteolysis
    Evolutionally difference for other animals - disadvantage for theses
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37
Q

Human Chorionic gondatropin (HCG) what produced by in what species, how and when detected, what basis for, when peak and effect

A
  • Produced from the trophoblast cell of humans and non-human primates -> produced by chorion
  • Detected in serum and urine as early as 8 to 10 days post conception
  • Basis for pregnancy tests
  • Peak at about 2.5 months of gestation
  • Luteotropic effect on the ovulatory corpus luteum - increases its lifespan therefore increases the progesterone
    ○ Binds to luteal LH receptors and if given to non-pregnancy females in the late follicular phase it can induce ovulation
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38
Q

Placental lactogen what secretes it, what species, function and the 2 types

A
  • Placenta secretes this hormone
  • Found in sheep, mice, rats, cow and humans
  • Act as a growth hormone, Act as a growth hormone thus stimulates the growth of the foetus (somatotropin)
    ○ Also has growth promoting effect on the mammary gland (lactogenic)
  • The degree to which placental lactogen is lactogenic or somatotropin depends on the species
39
Q

Oestrogen concentrations during gestation in animals

A
  • Horse and primates (humans) have high amounts from day 60 to the end of pregnancy
    ○ Need healthy foetus and placenta -> placentitis can result in decreased levels of oestrogen
  • In most species increases at the end of gestation (progestagens are converted to oestrogens
40
Q

twins in horses what occurs pre and post fixation

A
  • Before fixation fine
  • After fixation one will get one uterine horn will the other one will get the other uterine horn and the body for its placenta
    ○ Result in a smaller foal, more meconium on one (stressed)
41
Q

Mare that has udder formation premature what worried about and why

A

worried about impending parturition
○ Due to less hormones production -> foetus die, placenta then die -> drop of the progestagens
§ Smaller one dies due to small placenta that cannot provide enough nutrients
§ Sudden drop triggers the mare to think it needs to give birth
□ Sudden drop is characteristic of birth

42
Q

Mare has udder formation what is the treatment

A
  • Give them very high doses of progesterone
    ○ Can test whether working to see a reduction in the udder -> then wane the mare off progesterone if want to but can just keep giving
    The other foetus that dies -> mummification (ball of tissue and membranes)
43
Q

radiographs what animals used in, what see and when used

A
  • Small animal only
  • Can mainly just say have fluid filled uterus - now to use ultrasound to confirm
  • Most reliable later in pregnancy due to skeletal mineralization
  • Good for identification of foetal number
    ○ Last week of pregnancy preferred
  • Useful to identification of dead foetus
    ○ Intra-foetal gas
    ○ Disorganized skeletons
    ○ Overlapping skill bones
    ○ Foetal mummification
44
Q

ultrasound what are the 5 main reasons it is the preferred method

A 
○ Earlier confirmation of pregnancy 
○ Determination of foetal viability 
○ Estimate of foetal age 
○ +/- foetal sexing 
○ Can be used in all species
45
Q

Ultrasound what day can be performed in dogs and cats and when can count gestational sac

A

○ Can be performed from 20d in bitch and 14d in the queen
○ Count number of gestation sac from 25-35d - AFTER THAT NOT RELIABLE (use radiograph)
- Can determine gestation age - based on formulas from measurements of heads

46
Q

what are the 2 options for determining pregnancy in mares, what days can do from

A
  1. Palpation (30-40 days onwards)
    - Uterus feel changes during pregnancy, uterine contractions to move the embryo around
  2. Ultrasonography (rectal) 14 days onwards
    - Most common
    - Can go as early as 10 days but becomes difficult
    - NEED TO DO BEFORE FIXATION - 16 days -> need to squish the twin before fixation
    - Generally linear probe per rectum (5Mhz)
47
Q

What are the 5 special stages within the equine feotus development

A
  • Day 17-21 - change shape due to removal of glycocapsule
  • Day 21 -> the embryo appears in the ventral aspect of the yolk sac
  • Day 25 - heart beat day
  • Day 30 - yolk sac at the top move the embryo up
  • Day 42 - the embryo hangs by the umbilical cord
48
Q

What is the typical schedule for equine pregnancy scanning

A

Day 14 post ovulation - pregnancy & twin identification
Day 25 - 28 post ovulation - assess foetal viability (heart beat)
Day 40 post ovulation - confirm pregnancy (stud fee is usually due around this time)
Day 60 - 70 post ovulation - foetal sexing -> visualise the genital tubercle position
○ Only done by equine vets and need a 100% success rate as based on thousands of dollars
Day 150 - transabdominally sexing - external genitalia, penis, prepuce, teats, clitoris - not commonly done

49
Q

what are the 2 main ways bovine pregnancy diagnosis is done

A
  1. Manual Palpation
    - Cheap, reliable and accurate
    ○ 28-35 days after mating/AI CONTINUE
    - Does take a little bit longer
    - Pregnancy
    ○ Foetal size
    ○ Allantochorion
    ○ Amniotic vesicle
    ○ Placentome (60-70d)
  2. Ultrasound
    ○ B-mode is the most common used
50
Q

List 5 reasons pregnancy diagnosis is preformed in cows

A
  1. Better control of calving pattern
  2. Better nutritional management
  3. Between welfare/monitoring
    a. Identification and prevention of disease - pyometra, cysts, freemartin
  4. Genetic and phenotypic improvement
    a. Targeting culling strategies
  5. Increased profitability
51
Q

Aging the foetus in cows what are the 5 things you look for

A
  • Foetal size - head or thorax
    ○ Related to the radius of the diameter of the ventral ring
  • Presence of amniotic vesicle (6-11 weeks)
  • Differentiation of foetus - head, limb, ribs - around 8 weeks
    ○ Length of foetus 1.5 diameters
  • Presence and size of cotyledons - at about 10 weeks
  • Nature of the fluid - black vs cloudy
52
Q

What are the 5 T’s in soundness exam of rams

A

1) teeth
2) toes
3) testicles
4) torso
5) tossle - penis and preputial shealth

53
Q

what do you look for with toes, testicles, torso and otssle with ram soundness exam

A
  1. TOES
    - Not be overgrown - hoof trimming needs to be carried out in advance to joining
  2. TESTICLES
    - Determine whether the epididymis is large via palpation
    ○ Can also detect hard testicles, lumps or infections
    - Ideal scrotal circumference is 30cm or more (size of two soft drink cans)
    - SHOULD FEEL - firm but not hard
  3. TORSO
    - Rams need to be in good condition score (3.5-4) at start of 5 week joining period
    - Check for signs of body strike or fleece rot or lice
  4. TOSSLE - penis and preputial sheath
    - Expose penis to check for abnormalities or injuries
    - Feely moveable within prepuce - no pizzle rot
    - Can have calculi that becomes lodged in urethral process at the end of the penis -> required immediate surgical removal
    ○ Rams without urethral process are still fertile
54
Q

distrubution of total cardiac output in the foetus left and right ventricle and where blood come from

A

Left ventricle 35% of foetal cardiac output:
- Higher oxygen saturation
- oxygenated placental blood flow foramen ovale
- In L. atrium: oxygenated placental blood joined by small volume of deoxygenated blood returned from lungs; mixture leaves L. ventricle via aorta
Right ventricle 65% of foetal cardiac output:
3 sources:
1) Caudal vena cava:
- Oxygenated flow (placenta), deoxygenated flow – (caudal embryo)
2) Cranial vena cava (deoxygenated blood from cranial embryo)
3) Venous drainage of heart
Blood in R. ventricle: lower oxygen saturation than in L. ventricle

55
Q

mammary glands what type of gland and what does it secrete

A
  • Compound tubuloalveolar glands

- Secrete lipid via apocrine and casein by merocrine (leads to eosinophilic standing)

56
Q

What is the period of the zygote, embryo and foetus

A

Period of the zygote - from fertilisation of the ovum to implantation
Period of the embryo - the period within the first trimester of pregnancy in which organogenesis is largely completed
○ up to approximately days 35-45 in large domestic animal species
○ up to approximately day 20 in dogs and cats
Period of the foetus - the later stages of pregnancy in which tissue differentiation, growth and maturation predominate

57
Q

What is the key difference between a monotocous and a polytocous species in terms of the outcome
if a conceptus dies in utero

A

○ in monotocous species (those bearing only a single conceptus), death of the conceptus -> loss of pregnancy and resorption or expulsion of the conceptus
○ in polytocous species (those bearing multiple conceptuses), survival of at least one conceptus may allow the pregnancy to proceed, with dead foetuses being retained in utero, undergoing autolysis or mummification and being delivered at term with viable foetuses

58
Q

In which species can pseudopregnancy develop (following the death of one or more conceptuses)
and why?

A

○ death of a foetal foal after day 35 will therefore not result in abortion
instead, the mare will be pseudopregnant for a variable period and the dead foetus will be retained and undergo mummification - variable period until the endometrial cups are degenerated

59
Q

early embryonic mortality define

A

• early embryonic mortality = death of the conceptus at any stage up to the completion of organogenesis (i.e. death in the period of the zygote or embryo)

60
Q

are early embryonic mortality common in domestic animals and what are potential causes

A
  • the incidence of zygotic and embryonic losses is high in domestic animals and humans (e.g. 15- 30% of all pregnancies)
  • chromosomal abnormalities are an important cause of loss during this period
  • most chromosomal abnormalities involve numerical changes (e.g. monosomy, polysomy, triploidy, tetraploidy, mixoploidy) and many of these (e.g. triploidy) increase in incidence with increased age of the gametes
61
Q

what happens to the conceptus following early embryonic mortality and what is the most likely indicator that this mortality has occurred

A
  • if the conceptus dies in the early embryonic period, it is commonly resorbed
    ○ alternatively, it may be discharged from the uterus at the next oestrus
  • very early death of the conceptus (e.g. between days 4 and 10 of pregnancy) may -> normal timing of the next oestrus in the mother
    ○ alternatively, the return to oestrus may be delayed for a variable period of time
62
Q

what is a placental mole

A
  • rarely, following the death of an embryo, the extra-embryonic placental membranes (the bulk of the conceptus at this stage of pregnancy) may persist and continue to grow to form a cystic placental mole
  • moles may eventually undergo necrosis and be discharged from the uterus but some may become invasive and burrow into the uterus and even penetrate it to reach the peritoneal surface
63
Q

What are the four major fates of a foetus that dies in utero?

A
  • mummification
    • maceration
    • abortion
    • stillbirth
64
Q

how does mummification occur, what is the fate of the foetus and what species most common in

A
  • most often seen in polytocous species, especially pigs
  • the dead foetus or foetuses is/are retained in utero to undergo progressive dehydration
    ○ extra-embryonic membrane fluids are gradually resorbed and the membranes become applied to the desiccated foetus ->ultimate formation of a dry, firm, shrunken, leathery remnant composed mostly of dried skin and bones
  • in a monotocous species, a mummified foetus may be expelled or it may be retained indefinitely
  • in polytocous species, expulsion of one or more mummies may occasionally occur spontaneously but usually takes place at the time of delivery of viable foetuses
65
Q

what are the 3 Prerequisites for mummification

A
  1. presence of a functional corpus luteum -> maintenance of pregnancy with retention of the dead foetus(es)
  2. absence of bacterial infection within the uterus (including maintenance of a closed cervix)
  3. sufficient maturation of foetal skin to resist autolysis
66
Q

What are some common causes of mummification in cows, mares, sow, bitch and general causes

A 
cow - bovine viral diarrhoea (BVD) virus
• mare - twinning
• sow - porcine parvovirus
• bitch - canine herpesvirus
- other potential causes include genetic diseases (either inherited or acquired chromosomal mutations), protozoal infections (e.g. Neospora caninum or Toxoplasma gondii but NOT Tritrichomonas foetus) and placental insufficiency
67
Q

what is foetal macreation, what commonly associated with and what results from with mother

A

aceration = decomposition (softening, lysis and liquefaction) of the foetus and its membranes due to the action of bacterial products and/or proteolytic products of leukocytes
foetal maceration is almost
- always associated with bacterial infection but can also be seen in tritrichomoniasis in cattle
- associated with endometritis, metritis or pyometra, with a high probability of maternal septicaemia/toxaemia and death

68
Q

define abortion and stillbirth

A
  • abortion = delivery of a foetus (usually dead but occasionally alive) before the time of independent viability (i.e. prior to completion of normal gestation)
  • stillbirth = delivery of a dead foetus close to term when it should have been independently viable
69
Q

what is the normal things that leads to partiurition in sheep and cattle and therefore how is abortion or stillborn initiated

A

○ parturition in these species is initiated by a sharp rise in foetal cortisol production, in part due to increased foetal ACTH production but also due to increased responsiveness of the foetal adrenal cortices to ACTH
- same thing

70
Q

what are 2 potential causes of prolongation of gestation in domestic animals

A

1) holoprosencephaly - maternal ingestion of veratrum californicum - ○ prosencephalic (forebrain) and hence hypothalamic and/or neurohypophyseal malformation -> failure of foetal ACTH release to initiate parturition
2) nherited adenohypophyseal aplasia (severe hypoplasia) in Guernsey, Jersey and Swedish Red and White calves -> cessation of foetal growth and development at approximately the seventh month of gestation due to hypoplasia of target organs (e.g. thyroids, adrenal cortices and gonads)

71
Q

What is a potential consequence of any bacteraemia, systemic fungal infection, protozoal
parasitaemia or viraemia in a pregnant animal and how does it get to the foetus

A

placental colonisation -> placental insufficiency - more virulent straight to foetus -> necrosis and death
may reach the foetus directly from the chorion via the bloodstream, or they may extend over time from the chorion to the amnion and thence (via aspiration or swallowing of amniotic fluid) the foetus

72
Q

List 2 bacteria, 1 virus and 1 protozoa that causes infection of foetus in cow and sheep

A 
COW
- Campylobacter fetus subsp. venerealis
- C. fetus subsp. fetus
- Bovine herpesvirus-1* 
- Neospora caninum
SHEEP 
- Brucella melitensis* (sheep and goats)
- Brucella ovis (sheep)
- bluetongue
- toxoplasma gondii
73
Q

List 1 bacteria, 1 virus and 1 protozoa that causes infection of foetus in pig, horse, dog and cat

A 
PIG
- Brucella suis
- Porcine parvovirus
- Toxoplasma gondii
HORSE
- E. coli
- equine-herpesvirus-1
DOG
- Brucella canis
- Canine herpesvirus
- Toxoplasma gondii
CAT
- Feline panleukopenia virus
- Toxoplasma gondii
74
Q

What are the major factors that influence the outcome following viral infection of the conceptus

A

vulnerability of the conceptus is usually inversely proportional to its age
- infections in early pregnancy are more likely to kill the foetus or produce serious teratogenic effects
○ major anomalies tend to result from infections that occur prior to the stage at which the foetus can mount a neutralising antibody response to the virus

75
Q

in which species are bacterial and fungal infection most significant for abortion and how do infectious agents reach uterus in cattle

A

most often seen in cows and mares

most infections of foetal calves arrive haematogenous

76
Q

what are 2 other ways besides haematogenous spread do infectious agents reach bovine uterus and list the agents

A

1) venereally (Campylobacter fetus subsp. venerealis)

2) from the respiratory tract or via mucosal ulcers in the forestomach or abomasum (aspergillus fumigatus)

77
Q

how do most infectious agents usually reach the pregnant uterus of mares and which is it important to look at the cervical star in stilbirth investigation

A

ascending infections that enter the pregnant uterus via the cervix
○ ascending infections provoke inflammation and fibrosis of the chorioallantois at and adjacent to the cervical star (often spreading more extensively ventrally than dorsally due to gravity)

78
Q

non-infectious causes of abortion and stillbirth give some examples

A

1) inherited -> inherited chondrodysplastic in ruminants
2) nutritional - copper deficiency in lambs and calves, iosine deficiency in lambs
3) toxins -> griseofulvin -> meningocoele, meningoencephalocoele and cleft palate in kittens

79
Q

how common is twinning in mares and what are the results

A
  • twinning occurs in less than 1% of pregnancies in mares
  • chorionic villi fail to develop where the chorioallantoic membranes of the adjacent twins contact each other -> placental insufficiency and foetal growth retardation
  • in approximately 80% of cases, the available space within the uterus is shared equally -> death and abortion of both twins mid term
80
Q

why are foals predisposed to umbilical cord torsion, what features confirm that it is significant not just incidental finding

A
  • the extensive length of the umbilical cord (36-83 cm) in foetal foals predisposes to torsion
  • if a torsion is a genuinely significant finding, there is usually more than three complete turns present and (more importantly) there is evidence of congestion and oedema of the cord +/- placental membranes
81
Q

what is meant by the terms red bag in mares

A

n “red bag”, the caudal portion of the chorioallantois detaches from the endometrium at parturition so that the red chorion appears outermost at the mare’s vulva with the cervical star intact
- the foal is at risk of critical hypoxia

82
Q

what is adventitial placentation, which species occurs and what does it indicate

A

development of accessory villous placentation between the placentomes in ruminant species
○ the rudimentary placentation represents an attempt to compensate for inadequate development of placentomes
○ inadequate numbers of placentomes may be congenital (i.e. insufficient numbers of uterine caruncles in the cow) or more often acquired (e.g. due to inflammatory destruction of caruncles due to a previous or current bout of metritis; due to caruncular damage during removal of retained foetal membranes etc)

83
Q

what is the likelihood of obtaining a definitive diagnosis in an investigation of abortion or stillborn

A
  • the diagnostic rate based on sample submission to veterinary laboratories is at best 40-50% internationally
  • there is a greater probability of making a diagnosis when the cause is infectious and when multiple animals are affected (e.g. abortion storms)
84
Q

what gross lesions are suggestive of bacterial or fungal placentation in a foal and a ruminant

A 
GENERALLY
• oedema
• hyperaemia
• haemorrhage
• necrosis
• fibrosis
• chalky-white foci of dystrophic mineralisation
• obvious exudate
FOAL
- fibrosis and inflammation adjacent to cervical star
RUMINANTS
- cotyledons may have necrosis, infarction
85
Q

what is adenomatous dysplasia of the allantois in foals

A

○ solid or cystic nodules (up to 5 cm diameter) and plaques (up to 1-2 cm thick and up to 20 cm in diameter) grossly resembling tumours develop in the allantois, usually close to the umbilical cord

86
Q

how is foetal age estimated

A
  • the age of the foetus can be estimated from the weight, crown-rump length measurement and the extent of development of the haircoat and teeth (numerous published charts exist to assist with age estimation in domestic animals)
87
Q

what gross finding suggest neonate died after parturition or during parturition

A 
BEFORE 
- rib fracture/limb bones
- liver/bladder rupture
- congested and oedematous head
AFTER
- evidence of lung infiltration
-  presence of milk/colostrum in the stomach/abomasum
- presence of physiological thrombi (rather than post mortem blood clots) in umbilical veins and arteries
88
Q

what are common non-specific gross lesions of foetal hypoxia

A

relaxation of the anal sphincter -> release of meconium into the amnion -> staining of the amnion and skin +/- aspiration of meconium into the lungs and presence of meconium fragments in the conjunctival sac and nasal and oral cavities
- inhalation may cause bronchopneumonia

89
Q

what specimens would you collect from foetus and mother to permit further diagnostic investigation

A

liver
• lung
• stomach contents
- the following specimens should be collected into formalin for histopathology:
• ideally, specimens of all viscera, including the conjunctiva and brain
• as a minimum - whole brain, lungs, liver, spleen, thymus, kidneys and heart
- foetal blood and maternal blood 2 samples (2 weeks apart for titre change)

90
Q

what is the cervical star

A

star-shaped area where chorionic villi are absent from the chorioallantois.

91
Q

what is hippomane, which species and where found

A

equine, incidental finding found floating free in fluid of allantoic cavity

92
Q

what is characteristic of the amnitonic membrane in the foetal foal

A

As in other species, the amniotic membrane of a foetal foal is thin, smooth and transparent (below), with a glistening surface, large size and vasculature

93
Q

what are snowshoes or foetal slippers and function

A

These are rubbery masses of excess keratin on the solar aspects of the hooves.
- designed to protect the foetal membranes and the uterus from hoof trauma during pregnancy and the lower reproductive tract during parturition

94
Q

what are the marginal haematomas of the placenta of dogs and cats

A

maternal endometrial vascular endothelium degenerates at the margins of the placental zone
- thought to act as a source of iron for the foetus

DVM 2 - 2 (27 decks)

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