3. approach to pregnancy diagnosis Flashcards

1
Q

what is the clinical importance of early pregnancy diagnosis

A
  • rapidly identify fertility thus any problems in males and females to acto on it, as often a narrow window to breed
  • assist with production system (rebreed or cull, management change)
  • it may also satisfy the curiosity of the keeper
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2
Q

when is pseudopregnancy in the mare irrelevent

A

pregnancy failure/loss
1. occurs between days 1 and 5
- embryo lost whilst in uterine tube
- never knew she was pregnant as no MRP
- normal oestrus cycle

  1. between days 5 and 15
    - no MRP
    - normal oestrus cycle unless associated with uterine inflammation
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3
Q

what is pseudopregnancy type 1 in the mare

A

failure between days 15 and 36
- MRP has occured
- no return to oestrus
- primary CL will persist for normal lifespan for about 40 days then naturally regress
- CL can be lysed by the administration of pgf2a

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4
Q

what is pseudopregnancy type 2 in the mare

A

failure between day 36 and 140
- endometrial cups have formed –> producing eCG that will maintain the accessory CLs
- no return to oestrus
- accessory CLs will persist for their normal lifespan (150 days)
- CL cannot be lysed by the administration of pgf2a
- as eCG is protecting the CLs from prostaglandin
- wait for cusps to disappear before admin pgf2a

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5
Q

outline approaches to pregnancy diagnosis

A
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6
Q

explain how progesterone is used to diagnose pregnancy and how false -ves/+ves occur

A
  • no decline in progesterone in blood/milk 21 days from mating (exact date depends on species
  • false positivies may be due to progesterone remaining high with no pregnancy (ovarian pathology) for example persistent CL
  • false negatives due to confusing animals or poor sample storage
  • ideally requires frequent sampling
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7
Q

how are pregnancy recognition factors used to diagnose pregnancy

A

limited
- IFNT largely stays in uterine lumen, not circulation. few tests that can detect IFNT
- mare: dont know what the signal is
- dog: doesnt need pregnancy recognition hormone so nothing to detect

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8
Q

how are feto-pacental oestrogens used to diagnose pregnancy

A

later on
- the fet-placental unit produces both progesterone and oestrogens
- oestrogens are often found mid-pregnancy onwards in both plasma and urine
- higher concerntrations of oestrogen mid-pregnancy than in oestrus
- no false positive diagnoses
- pregnancy specific oestrogens
- however ideally you want to detect the pregnancy earlier than this method permits

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9
Q

what other pregnancy specific hormones are used to diagnose pregnancy

A

relaxin
- produced by CL in some species
- but also produced in placenta (bitch/mare)
- used for PD in bitch and queen (cannot use progesterone in dog)

placental lactogens
- produced by the placenta in several species
- luteotrophic
- commercial tests

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10
Q

discuss rectal palpation for pregnancy diagnosis

A
  • requires systematic appraoch
  • look for one horn and travel along to find the other
  • look for one being enlarged
  • unpregnant will be soft but the pregnant will be notable fluid filled and doughy
  • best done in monovular species
  • detects ballottment (can just about feel the head as theyll be deep in the abdomen and membrane slip (signs of pregnancy)
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11
Q

what are you looking for in abdominal palpation for PD

A
  • detection of enlarged uterus
  • ballottement of the fetus
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12
Q

how do you diagnose pregnancy via ultrasound

A

2 methods:
- doppler applied transabdominally (less common in animals than human)
- B mode real time via transrectal or transabdominal (pigs, dogs, cats probe cranial to hind limb pointing caudal)

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13
Q

what can you see on ultrasound in the early stages of pregnancy

A
  • detection of conceptus
  • normally anechoic structure
  • representing yolk sac
  • early pregnancy is packed full of fluids
  • amnion and allantois fluids as pregnancy moves forward but initially yolk sac
  • i.e anechoic in nature as fluid
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14
Q

what is the clinical significance of eultrasound examination for migration of equine conceptus

A
  • careful examination required to ensure the diagnosis of twins enabling remedial action as appropriate
  • 2 embryos in image below: one must be popped therefore diagnosis must be made early to allow this to be done
  • requires careful palpation as these embryos are migratin at this point and might not be ipsilateral with the CL ovary
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15
Q

what can you see on ultrasound at a slightly later stage of pregnancy

A

detection of an embryo and heartbeat

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16
Q

what can you see on ultrasound later on in pregnancy

A

bovine: see spinal cord and ribs. at the top, circles surrounded by anechoic area might be placentomes.
canine: limb bid development

17
Q

why should you check ovaries while doing a PD ultrasound

A

demonstrate CLs or other likely confirmatory changes

18
Q

how do you diagnose pregnancy via radiograph

A
  • possibly detect uterine enlargement
  • see mineralisation of the skeleton at the point where mineralisation occurs (depends on gestation length)
  • common in dogs to count number of offspring but hard and never definitive
19
Q

list physical changes associated with pregnancy

A
  • increased appetite
  • weight gain
  • abdominal enlargement
  • relaxation of the perineal tissue
20
Q

what physical changes are indicative of pregnancy

A
  • auscultation of fetal heart beats
  • uterine artery enlargement and change in flow (turbulent buzzing feel called fremitus)
21
Q

list external secondary changes in pregnancy

A
  • no return to oesturs
  • teat and mammary gland enlargement and reddening (not reliable in bitch or cow except first calving, dog will develop whether preg or not)
  • secretion of milk in late pregnancy
  • waxing up in the last few weeks prior to birth (sticks to bottom of teat)
22
Q

list internal secondary changes in pregnancy

A
  • cervial mucous: long period of elevated plasma progesterone –> mucus may become very dry and tacky (thick, opaque, pale yellow and rubbery)
  • vaginal wall thinning: oestrogen increases layers of vaginal wall, prolonged progesterone = few layers in vaginal epithelium (detected by biopsy)
23
Q

which methods are most commonly used for pregnancy diagnosis in the cow

A

blue = common
- failure to return to oestrus is a key marker in cows
- will be presented to vet for difinitive dx
- farmer might test milk

24
Q

compare pregnancy diagnosis techniques in the cow and their relative levels of accuracy

A
  • milk progesterone is earliest method we can use. pretty good at determining not pregnant, less good at saying yes is pregnant
  • rectal palp cant be done reliably until later on
25
Q

what are the most commonly used methods of PD in sheep

A
  • failure to be raddled best way to assume pregnant
  • sheep are very fertile
  • transabdo US from day 30 to detect fluid in uterine horns then later detect the caruncles. but normally do this around 50-60 days to determine number of offsprng to adapt husbandry
26
Q

what are th most common methods of PD in the sow

A
  • sow usually very fertile
  • not returning to oestrus good indicator
  • transrectal takes longer to do, usually transabdo to look for fluid in the uterine horns. later in preg can see embryo
27
Q

what are the most common methods of PD in the mare

A

trans rectal US done from day 12-15 for detection of twins (esp on stud farms)

28
Q

what are the most common methods of PD in the bitch

A
29
Q

whaty are the nmost common methods of PD in the queen

A
  • transabdo US
  • relaxin
  • abdo palp
30
Q

if a pregnancy is lost on day 60 in the mare she will:

A

be pseudopregant until day 160

31
Q

how early in pregnancy can embryonic/fetal fluids be reliably detected in the cow

A

day 24

32
Q

the presence of which hormone in the blood indicates pregnancy in the dog

A

relaxin

33
Q

in the cow, which one of the following indicates to the owner that she might be in early pregnancy

A

failure to return to oestrus 21 days after mating

34
Q

you are presented with a cow for PD 50 days after mating. what is the most appropriate PD method

A

transrectal palpation of enlarged uterine horn

35
Q

what is the effect of eCG on the pregnant horse

A

stimulates formation of accessory CL and progesterone

36
Q

in the sow when does the placenta take over as the primary source of progesterone

A

never

37
Q

which cell produce placental lactogen in the bovine

A

binucleate cells