5. Pregnancy pathologies - MPG | Quizlet ZC

Gestations days: embryonic period

1-40 days

Gestation days: Fetus period

41-birth

Define EED - early embryonic death

Death of conceptus before 40 days of gestation

What percentage of mares abort by day 50

15-20%

Highest time of abortion 0-40 days

Methods of diagnosing EED

1. C/s

2. USG

3. Rectal

4. Additional tests - progesterone test

C/s of EED

1. Return of estrus

2. Irregular shape of embryo vesicles

3. Prolonged mobility >16d

4. Changes in fluid in vesicles

5. Abnormal development of fetal membranes

Causes of EED

1. Twins

2. Endometrial pathologies: inflammatory or none

3. Low progesterone

4. Location of embryo vesicles during fixation

5. Mare age - quality of eggs reduce 14-15yrs

6. Oocyte quality

7. Stress

8. Malnutrition - 1st semester horse provides for itself

9. Chromosomal ab

10. Toxins: mycotoxins, pesticides, ergot alkaloid, neotyphodium, coenophialum

What is the most common non-infectious cause of abortions / EED in mare

Twin pregnancy 0.5-14%

Mares are very good are reducing twin pregnancy, one or both - physiological process

Main cause of twin pregnancy

Multiple ovulation - dyzygote

Monozygotic is very rare

Predisposing factors to twin pregnancy & EED

1. Thoroughbreds 20-30% & large breeds

2. Older mares

3. Genetics / inheritance

4. Foal heat breeding

5. Stimulated ovulation

What is the case of miscarriage / EDD in twin pregnancy

1. Placental insufficiency (whole placenta is needed for BF & nutrition)

2. One fetus develpo faster, taking blood supply & other dies

3. Death of one fetus usually causes abortion of both

4. Miscarriage often in 5-9months

When does abortion of twins usually occur

5-9 months

Results of twin pregnancies

1. Early resorption or fetal loss

2. Late miscarriage (5-9m) - most often

3. Birth of small, developmentally delayed foals

What is the most common results of twin pregnancy

Late miscarriage 5-9 months

What is the ideal outcome of twins pregnancy's

Mares usually effective in reducing pregnancies

One of the twins dies & mummified, before end of placentation

Allows the other one to survive until birth & not inflammation

If any other outcomes occur 99% loss of both

What percentage of twin pregnancies are both healthy

7%

When can twin pregnancies be manually reduced

Needs to be done before day fixation, 15-16d

Still mobile, allows preservation of one & squeezing of another

Methods of elimination of one of twins

1. Manual elimination - squeezing

2. Transvaginal USG guided aspiration (TVUA) - hard & not effective

3. Injection of embryonic vesicle with amikcan sulfate / penicillin

4. Angus mc Kinnon procedure 45-50d

5. Cranio-cervical dislocation (CCD) rectally 60-100d

6. CCD laparotomy

7. Trans abdominal USG guided puncture - potassium chloride / procaine penicillin

What is TVUA used for

Transvaginal ultrasound guided aspiration

Elimination of one of twins

What is angus mc kinnon procedure & when is it done

Elimination of one of the twins

Between 45-50 days

Detachment of umbilical cord from amniotic membranes, Reducing blood flow

What is CCD, when i it done

Cranio-cervical dislocation (CCD) - by Laparotomy

Elimination of one of twins, 60-110d

Dislocation of the first cervical vertrabea from the cranium

Disrupting the ligaments attached & severing spinal cord

Why is elimination of a twin before placental formation is complete important?

Allows remaining fetus to use the entire endometrial surface for nutrition & oxygen exchanged & grow to full potential

Describe transabdominal USG guided puncture: what is it used for, how it done & when

Elimination of one of the twins by

Injection of embryonic vesicle with procaine penicillin / potassium chloride into heart, thorax or abdomen

Done in later stage of gestation

Can mares return to breeding after late miscarriage

No, reproductive season will be lost & can even affect next season

Risk of late miscarriage of twins

1. Loss of season / affecting next season

2. Dystocia

3. Cervical rupture

4. Retained placenta

Etc.

inducing abortion by PGF2a should be considered

How to remove pregnancy in late gestation if there is risk of dystocia, retained placenta or cervical rupture?

Injection PGF2a

Causes of low progesterone / failure of pregnancy recognition

Progesterone will be low when the uterus doesnt recgonise the embryo & induced luteolysis

1. Embryo can't block luteolysis - bc its too small or doesn't fix

When will embryonic death off if there is low progesterone

Day 20

At what age does mare oocyte quality start to decrease

14-16/18yrs

Is EED more common in young or old mares

Older mares!

When foes EED usually occur in older mares with low quality oocytes

2-4d post ov

@ time of embryo genom activation (EGA)

Define fetus abortion

Expulsion of non-viable fetus before day 300, after day 40

When do fetus abortions usually occur

40-80 days

Some as late as 140d

What causes "Abortion storm"

EHV-1

Important to isolate horses that aborted & prevent contact

Variants 5-7-9 month pregnancy

Most common cause of fetus abortion

1. Twins

2. Older mares

3. Mares with endometriosis

4. EHV-1

Main infectious cause of abortion & %

Equine herpes virus - EHV-1

Causes 18% of all abortions

Infections agents causing abortions

1. EHV-1 (esp if more than one horse)

2. Equine infectious anemia virus

3. Equine arteritis virus

4. Leptospirosis

5. Salmonella

Non infecitous causes of abortion

1. Umbilical cord torsion

2. Placentits

3. Hydropsies - rare

4. Trauma

5. Mare reproductive loss syndrome

6. Fetal developmental abnormalities - malformations

Why is umbilical cord torsion common in horses

Bc equine fetus are very active & movement can cause it to twists 360 E degress

Especially in the last trimesters

Causes of Placentitis

1. Viruses: EVA, EHV-1

2. Bactria: streptococcus B. Hemolytic, E. Coli, Pseudomonas aeruginosa, Klebsiella Pneumoniae, Leptospira, Crossiella equi

3. Fungi - Aspergillus & mucor

Does Placentitis usually cause late or early abortions

Late

Routes of infection of Placentitis

1. Ascending: causes separation of placenta from internal orifice of cervix i.e. after dystocia etc. (likely to reoccur)

2. Hematogenous infections:

leptospira (disseminated or multifocal placenta inflammation)

Virus

3. Infection during mating: crossiella equi, latent until pregnancy

Cause of norcardiosis of placenta

Crossiella equi

Infection during mating that remains latent until later in pregnancy & changes are in uterine body

C/s of Placentitis

1. Premature growth of mammary glands & milked production

2. Cervical relation / soft

3. Vaginal discharge

4. Abortion

5. Still birth

6. Premature parturition - immature / unprepared foals

7. Small foals with systemic infection

Is Placentitis sympatomatic or asympatomic

Mostly asymptomatic, with normal haematological results

How to diagnose Placentitis

1. C/s: mamary gl & vaginal discharge

2. Blood samples: normal

3. Bacteriological & cytology: vaginal / cervical discharge

4. USG: apparence of placenta at internal orifice of cervix

- thickened (at veneral wall)

- chorioallantoic edema

- serration of placenta from uterus

& vitality of fetus

What can be seen in USG of horse with Placentitis

check at cervical start

1. Thickness

2. Chorioallantoic edema

3. Separation of placenta from uterus

Also check viability of fetus

Thickening & separation of placenta & uteurs at cervical star is a sign of what?

Placentitis

Which part of the uterus do you check he combined thickness of the uterine wall & placenta & why?

Ventral wall

Bc the dorsal wall of placenta is thicker & edema is observed in last month of pregnancy in healthy mares

What to check in assessment of fetus during Placentitis

1. Fetal hr

2. Mobility

3. Size

4. Transparency of amniotic fluid

Treatment of Placentitis

ASAP

1. Broad spec ab at therapeutic concentration in amniotic fluid

2. NSAIDS

3. Pentoxiphylline & aspirin: improve circulation

Name two type of hydrous & describe

1. Hydro allantois

- more rare, sudden increase in volume of allantoic fluids

- volume 110-230L (normal 8-18L)

- mediate disseminated placental inflammation & endometrial vasculitis

2. Hydroamnios

- fetal swallowing reflex disorders

What is normal volume of allantoic fluid vs hydrops

Normal 8-18L

Hydrops 110-230L

What does fetal swallowing refex cause

Hydroamnios

Which is more common hydroallantois or hydroamnios?

Hydroamnios - is more common but still rare

What degress of torsion can occur in uterus

90-360, even 540

When does uterine torsion usually occur & why

5th-8ht month pregnancy / 3rd trimester

Bc huge tissue of uterus

Also affect cervix, vagina & intestines

Cause of uterine torsion

Fetal movements to get proper positions

Increase motility of fetus in 3rd trimester

Rolling of mare on back

A lot of tissue of uterus

C/s of uterine torsion

1. Pain / colic

2. Restlessness

3. Sweating

4. Increased urination

5. Apathy, anorexia, fever

6. Increase HR, BR

7. PK dont work well

8. Reduced motility / peristalsis

How to diagnose uterine torsion

1. Rectal palpation - torsion of broad ligament

2. USG: Swelling & thickness of the walls, enlargement of BV & lig

3. Viability of fetus: HR & amniotic fluid clarity

Treatment of uterine torsion: conservative & corrective

Conservative:

1. Reposition w hand if <270 rotation

2. Rolling

(Risk fetal, placenta & uterine injuries)

Corrective:

1. Surgery: standing flank laparotomy, ventral midline laparotomy

If torsion is >270 how is it treated

Surgery

When can you treat torsion by reposition

1. If less than 270 degree turn

2. Full term pregnancy

3. Dilated cervix

Standing with epidural