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Flashcards in Disorders of Pregnancy in the Mare Deck (76)
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1
Q

Early Pregnancy: Pre-fixation (before day 16) events

A
• Selective transport of
fertilized ova (PGE)
• Embryo reaches the
uterus at the blastocyst
stage about 6 days after
fertilization
• Blastocyst expands and
forms the vesicle
• Transuterine migration
provides signals
preventing luteolysis
2
Q

Early Pregnancy: Fixation

A
• 16-17 days
• Fixation of the embryo
does not occur
necessarily in the horn
ipsilateral to the CL
bearing ovary
• Day 35 formation of the
endometrial cups
3
Q

endometrial cups form on what day?

A

day 35

4
Q

Pregnancy: Placentation

A
• Development of villi starts by
day 45 covering the entire
chorioallantoic surface and
interdigitate with corresponding
endometrial
• Microcotyledonary, diffuse
5
Q

Emergencies in pregnancy

A
• Colic in the pregnant mare
• Abnormal vaginal discharge
• Premature mammary gland
development or lactation
• Ventral abdominal wall abnormalities
6
Q

Signs of impending pregnancy loss

A

• Irregular and indented vesicle
• Fluid in the uterine lumen
• Echogenic spots (speckling) of the embryonic vesicle
• No fetal heartbeat
• Poor definition of fetal structures
• Increased echogenicity of fetal fluid
• Largest diameter of the fetal vesicle is 2 standard deviation
smaller that the mean of the age of pregnancy
• Slow growth in size
• Failure of fixation
• Echogenic ring within the vesicle
• Disorganized membranes and collapsed amnion
• Increase edema and exaggerated endometrial folds
• Presence of fluid surrounding the embryonic vesicle

7
Q

Ultrasonography - diagnosis of pregnancy problems- approach

A
• Fetus
 Heart rate and rhythm
 Size and number
 Fetal activity
 Fetal tone
• Quantity and quality of allantoic and
amniotic fluid
• Fetal membranes/ Thickness of the
uteroplacental unit
8
Q

Fetal heart rate

A
• 1.5 to 1.8 x that of the dam
• Faster in early pregnancy
• Decreases from 120 bpm in
the first 3 months to 60 bpm
in the last couple of weeks
• Increases in response to fetal
activity by 25 to 40 beats
• Fetal activity and increased
heart responses occur 48 to
72 hours prior to parturition
9
Q

fetal biometrics

A
• Aorta systolic
diameter
• Biparietal
diameter
• Eye volume
• Kidney cross
sectional area
10
Q

Evaluation of the placenta: Transabdominal

A
• Epitheliochorial, covers
the entire uterus except
at the level of the
cervical star
• Examination
percutaneous and per
rectum
• Focus of the
examination Combined
uteroplacental thickness
11
Q

Combined uteroplacental thickness (CUPT) - where is it measured

A

• 3 to 5 cm cranial to the cervix
between the middle branch of the
uterine artery and the allantoic fluid

12
Q

Endocrine evaluation - Progesterone/Progestogen

A

 Main source in the first trimester : Ovary
 Main source past 80 days is the placenta
– Convert pregnenolone to progesterone
– Progestin (5 α pregnanes)
• Decreased myometrial activity and prevent abortion
• Progesterone peaks 24 to 48 hours prior to parturition

13
Q

Endocrine evaluation - Estrogens

A

• Total estrogens should be > 1000 pg/ml

14
Q

Features of fetal stress

A

• Persistent fetal tachycardia or bradycardia
• Large or progressively enlarging areas of
placental detachment
• Rapid drop in progestins (Houghton et al 1991,
Rossdale et al 1991)

15
Q

Features of death or imminent abortion

A

• Large of progressively enlarging areas of
placental detachment
• Premature mammary development and lactation

16
Q

Management of compromised pregnancy

A
  • Limit effect of prostaglandin (NSAID)
  • Ensure myometrial quiescence
  • Antibiotics (placentitis)
  • Improve oxygenation and reduce effect of inflammation byproducts
  • Support fetal metabolism
17
Q

Bacterial placentitis isolates

A
• Streptococcus spp. (S.
zooepidemicus)
• Staphylococcus spp.
• E.coli
• Klebsiella spp
• Enterobacter spp.
• Pseudomonas spp.
• Salmonella abortus equi
18
Q

Ascending placentitis causes abortion between what months of gestation?

A

6 and 9

19
Q

• S. equi subsp. zooepidemicus

placentitis appearance

A

acute and focal or diffuse

20
Q

ascending placentitis - bacteria

A

S. equi subsp. zooepidemicus
E. Coli
Psuedomonas aeruginosa

21
Q

Escherichia coli placentitis

A

 Usually acute before 7 months
 chronic and focally extensive,
involving the cervical star, after 9
months of gestation

22
Q

Pseudomonas aeruginosa

placentitis

A

Either focal or diffuse with a
thickened and discolored cervical
star

23
Q

Dx of bacterial placentitis

A

clinical signs
transrectal ultrasonography
bacteriology

24
Q

clinical signs of bacterial placentitis

A
 Premature udder
development or
lactation
 Vaginal discharge
 Asymptomatic
25
Q

• Transrectal

Ultrasonography finding with bacterial placentitis

A

 Increased CUPT
 Areas of placental
separation

26
Q

Features of placentitis in the dam

A
  • Premature mammary gland development

* Mucopurulent vaginal discharge (ascendant placentitis

27
Q

Features of placentitis in the fetus

A

•Persistent fetal tachycardia

28
Q

Features of placentitis in the uteroplacental unit

A
  • Thickening of the uterine wall (>13 mm)
  • Increased CUPT (>17.5 mm)
  • Pockets of hyperechoic fluids (pus)
  • Areas of placental separation
29
Q

Features of placentitis - endocrinology

A

•Increased total progestogen concentration
•Decreased total estrogens
•Elevation of acute phase proteins (Serum amyloid A and
Haptoglobin)

30
Q

Leptospirosis locations

A

• More frequently
diagnosed in Kentucky,
Florida and South
America

31
Q

Leptospirosis – Clinical presentation

A
• Clinical signs in the mare
not always present
• Fever
• Hematuria
• Acute renal failure
• Uveitis may develop weeks
after abortion
• Stillborn or weak foals
• Abortion
32
Q

Abortion occurs when with lepto?

A

• Mid to late term abortion
(most in the last 3 months of
gestation)
• Not all infected mares abort

33
Q

Leptospirosis – Pathological findings placenta

A
• Placentitis not involving
cervical star
• Heavy, edematous,
hemorrhagic
• Occasionally covered with a
brown mucoid material on
the chorionic surface
• Calcification
• Funisitis in some cases
34
Q

Leptospirosis – Pathological findings fetus

A

• Mild to moderate icterus
• Liver enlargement, hepatitis
• Tubulonephrosis and
interstitial nephritis

35
Q

Leptospirosis - Diagnosis

A

• Fetal and placental lesions
• Fetal antibodies
• Isolation from placenta or renal tubules
• Immunohistochemistry of the placenta umbilical
cord or fetal kidney and liver
• PCR
• High-titers agglutinating antibody in mare
(>1:6,400 often > 12,800)

36
Q

Leptospirosis - Prevention

A

• Isolation of aborting mare for 14 to 16 weeks
• Urine testing by FAT for shedding
• Treatment of possible shedders??
 Antibiotic treatment (Oxytetracycline 5 mg/kg, IV,
SID or penicillin G, 20,000 IU/kg IM BID) for 5 to 10
days has been reported to help prevent abortion
during an outbreak
• Limit exposure to stagnant water
• Control of reservoir animals
• Vaccine is available

37
Q

Nocardioform placentitis

A
• Chronic placentitis
• Late term abortion or
premature birth
• Severe exudative,
mucopurulent, and necrotizing
placentitis at the junction of the
placental body and horns
• Fetus severely
underdeveloped
38
Q

Nocardioform placentitis - most severe infections are caused by what?

A

actinomycete Crossiella equi

39
Q

EHV transmission

A
• Transmission:
• Respiratory
• Abortion may be stress related
• May occur in vaccinated mares (reactivation of
latent infection
40
Q

When does abortion occur with EHV?

A

• Abortion usually 7 months to term
• Abortion- fresh fetus
• Fetuses > 8 moths present characteristic
lesions particularly with EHV-1

41
Q

Diagnosis of EHV abortion

A
Necropsy
• Rib impression
• Focal necrosis in the liver
• Presence of pleural fluid
• Fibrin in the trachea
• Vascular necrosis
• Intra-nuclear inclusion
 Laboratory
• Virus isolation
• Immunochemistry, or
polymerase chain reaction (PCR)
on fetal lung, liver, spleen, and
thymus
42
Q

prevention of EHV abortion

A

• Vaccination (killed vaccine at
5, 7, 9 months)
• Separation of pregnant mares
from high risk horses

43
Q

Equine viral arteritis (EVA)

A

non arthropod-borne virus of

togaviridae family

44
Q

EVA transmission

A

primarily respiratory and

venereal, fecal and urinary possible

45
Q

Abortion with EVA

A

• Abortion, usually 5 mos. to term or 20-40
days post-exposure, up to 50-70% of infected
mares may abort
• Fetus and placenta in variable degree of
autolysis

46
Q

Clinical signs of EVA

A

• Clinical signs: Limb edema, lameness, nasal and
ocular discharge, conjunctivitis, facial edema,
preputial edema, urticaria, pyrexia, depression and
anorexia
• Fetus
• Subcutaneous edema
• Petichial hemorrhages in the pleura and epicardium
• Increased pleural fluid

47
Q

lab dx of EVA

A
• Seroconversion
• Virus isolation: nasal swabs, buffy coat, urine or semen of
adult, placenta, spleen of fetus
• Immunohistochemistry
• PCR
48
Q

Prevention and control of EVA

A
Test stallions / teasers
• Require negative status (AI)
• Vaccination MLV
 Stallions
 NON-PREGNANT MARES
 Always separate vaccinated animals from pregnant
mare for at least 30 days
49
Q

Fungal Abortion

A

• Aspergillus fumigatus and Mucor spp most
commonly but others also involved
• Usually ascending, some hematogenous
• Chorion may be dry and leathery or have a
brown, tenacious exudate, especially at the
cervical area

50
Q

Protozoal Abortion

A
  • Neospora spp.
  • Trypanosoma equiperdum (dourine)
  • Babesia equi or caballi (piroplasmosis)
51
Q

Mare Reproductive Loss Syndrome associated with what?

A

Eastern tent caterpillar and placental edema

52
Q

Non-infectious Abortion

A
  • Twinning**
  • Umbilical cord torsion**
  • Progesterone deficiency
  • Stress due to illness, trauma, transport
  • Chromosomal or genetic abnormalities
  • Fetal abnormalities
  • Placental insufficiency or abnormalities
53
Q

Twinning in the mare

A
The leading cause of non
infectious abortion
(Thoroughbred, Warmblood)
• All (almost all) equine twins are
dizygotic
• Double ovulations
54
Q

Twinning - Diagnosis

A
• Ultrasonography
 Transrectal
 Transabdominal
 ECG
• Source of errors
 Stage of development
 Uterine cysts
55
Q

Management of twin pregnancies

A
• Before fixation
 crushing, 100% effective if
twins are separated
 No effect on pregnancy if
done properly
• After fixation
 Bilateral: crushing
 Unilateral:
– Wait and see
– Play the odds
56
Q

Management of twin pregnancies - past 30 days

A
 Transvaginal ultrasoundguided
aspiration
 Intra-cardiac injection
 Wait and see
 Abort both and loose
season
57
Q

Management of twin pregnancies

• Past 65 days:

A
 Transabdominal Intracardiac
injection
 Cervical dislocation
 Surgical removal
 Abort both and loose
season
 Complications
58
Q

Prevention of twin pregnancies

A
• Check mare during
estrus for double
follicles
• Predisposed breeds!
• Check for pregnancy
early and often
• Manual crushing
(easier said than
done!)
59
Q

Uterine Torsion

A
• Colic varying degree of
intensity or just ADR
• Essential rule out in any case
of colic in pregnant mares (>5
months)
• Diagnosis based on transrectal
palpation
• History Fetal and placental
evaluation important for choice
of method of correction
60
Q

Non-surgical correction of uterine torsion: Rolling

A
• General anesthesia
• Mare is place on
lateral recumbency
on the side of torsion
• Plank on the opposite
side
• Roll at least 3 times
• Check in sternal
position
61
Q

Surgical correction of uterine torsion

A

midline laparotomy

62
Q

Hydrops allantois

A

Excessive accumulation of allantoic

fluid

63
Q

Hydrops amnii

A

Excessive amount of amniotic fluid,
edematous umbilical cord, abnormal
fetus

64
Q

Hydrallantois - Hydramnios - causes

A
  • Abnormal placentation
  • Abnormal umbilical cord
  • Lack of swallowing of liquid fluid
  • Overproduction of fluid
  • Fetal abnormalities
  • Genetics
65
Q

Hydrallantois - Hydramnios - dx

A

Clinical signs, palpation, girth

measurement

66
Q

Hydrallantois - Hydramnios - tx

A
  • Induction of abortion/parturition
  • Conservative management
  • Humane euthanasia
67
Q

Prolonged Gestation due to Fescue Tox

A
• Endophyte: Acremonium
coenophialum
• Alkaloids: Ergovaline, Loline
• Endocrine effects
• Low plasma progesterone
concentration
• Low relaxin level
68
Q

Clinical effects of fescue tox

A
• Placental edema thickening
• Premature placental
separation (Red bag)
• Abortion
• Agalactia
• Weak /immature foals
69
Q

Tx/Px of Fescue Tox

A
  • Remove from pasture

* Domperidone

70
Q

Prolonged Gestation

Congenital hypothyroid dysmaturity syndrome - cause

A
  • Mustard toxicity

* Brassica spp

71
Q

Endocrine effects of brassica tox

A

• Glucosinolates broken down into
thiocyanates and thiouracil
analogs are goitrogenic

72
Q

Clinical effects of mustard tox

A
• Poor development (prematurity
signs)
• Incomplete ossification of the
cuboidal bones
• Flexural deformities of the
forelimbs
• Ruptured digital extensors
• Hydrocephalus, patent urachus
73
Q

Prolonged Gestation

Intrauterine growth retardation - cause

A
  • Poor nutrition
  • Abnormal placentation
  • Fetal abnormalities
74
Q

Bloody vaginal discharge

A

• Impending abortion
• Hemorrhage from
varicose veins

75
Q

Differential diagnosis of body wall defects

A
• Severe ventral edema
• Hernia
• Prepubic tendon
rupture
• Rupture of the
mammary ligament
• Udder edema
76
Q

Management of mares with body wall defects

A
• Confine / control exercise
• Control food and water
intake
• Symptomatic treatment in
case of ventral wall edema
• Support body wall
• Pain management
• Close monitoring for foaling
• Induction of parturition
when appropriate