The Peripartum Period p222-228

Question 1

What are the three periparturient events that have that most devastating effects on neonatal survival?

Answer 1

Hypoxia, infection, derangement of an in utero development

Question 2

When do maternal progestagen concentrations stabilize? When do they rise sharply? When do they fall greatly?

Answer 2

Stabilize between days 150-315, where they begin to rise sharply, before falling last 1-2 days.

Question 3

Where are progestagens synthesized in the mare?

A) Corpus luteum
B) Uterine wall
C) Placenta
D) Hypothalmus

Answer 3

Progestagens are synthesized in the uterine placental tissues, from pregnenolone derived from the fetus.

Question 4

Where does relaxin come from in the pregnant mare, and what is it marker for?

A) Placenta, marker for fetoplacental well-being and periparturient complications in the mare
B) Corpus luteum, marker for readiness of birth
C) Fetus, marker for readiness of birth
D) Uterine wall, marker for fetoplacental well-being and periparturient complications in the mare

Answer 4

A) Placenta, marker for fetoplacental well-being and periparturient complications in the mare

In healthy mares, concentrations increase from about day 80 to day 175, a value that persists at birth

Question 5

Mammary secretions change in electrolyte concentrations as parturition nears. Which of the following correctly lists these changes?

A) Sodium and potassium decrease, calcium increases
B) Sodium increases, potassium and calcium decrease
C) Sodium decrease, potassium and calcium increase
D) Sodium, potassium and calcium all increase

Answer 5

C) Sodium decrease, potassium and calcium increase

Calcium is seen to be a reliable indicator for birth and increases over the last 72 hours of gestation. Look for an increase over 40 mg/dL.

Question 6

Milk pH changes how toward impending parturition?

Answer 6

pH will decline to approx 6.4 over the final week of parturition.

Question 7

How does fetal heart rate of the foal change throughout gestation?

Answer 7

The heartbeat of the foal is regular and decreases from greater than 120 beats/min before day 160 of gestation to between 60 and 90 beats/min in late gestation?

Question 8

What does persistent bradycardia of the fetus indicate?

Answer 8

Fetal distress, often mediated by a vagal response to hypoxia.

Question 9

What are some conditions that can cause chronic asphyxia in the large animal fetus?

Answer 9

Chronic placentitis, villous atrophy, twin and post term pregnancies, ingestion of endophyte-infected fescue grass

Question 10

How do repeated episodes of hypoxemia during gestation affect the fetus?

Answer 10

Glycogen stores are depleted, impairing the ability of the heart to effectively pump blood during subsequent hypoxemic episodes. These foals are at risk of developing hypoglycemia and hypothermia.

Question 11

Exposure to what as a foal can actually produce a fetus that may be better equipped to handle a premature delivery than a ‘normal’ fetus that is abruptly displaced through induction of labor or c-section?

Answer 11

A fetus in an adverse in utero environment may be more tolerant of premature delivery.

Question 12

What is the most common cause of placentits in the mare?

Answer 12

Ascending infection from a relaxed cervix.

Question 13

What is the normal combined thickness of the uterus and placenta (CTUP) throughout gestation? How does parity affect the CTUP during mid gestation? What values would indicate placental pathology?

Answer 13

Around 6 mm at 7 mths and increasing to 10-12 at term

Primiparous mares have thicker CTUP than multiparous mares

Measurements at 12 mm at 11 mths or 15 mm at 12 mths indicate placental pathology

Question 14

Match the gross placental types with the species.

Bovine, Caprine, Equine, Ovine, Porcine

A) Diffuse - the entire surface of of the allantochorion is involved in formation of the placenta
B) Cotyledonary - multiple, discrete areas of attachment called cotyledons are formed by interaction of patches of allantochorion with endometrium. Fetal portion of this type are cotyledons, maternal contact sits caruncles and the entire complex called a placentome.
C) Zonary - placenta takes form of a complete or incomplete band of tissue surrounding the fetus
D) Discoid - single placenta is formed and is discoid in shape

Answer 14

A) Equine and Porcine
B) Bovine, Caprine and Ovine
C) Dogs and cats
D) Primates and rodents

Question 15

Match the species with its type of tissue layering between maternal and fetal vascular systems

Bovine, Caprine, Equine, Ovine, Porcine

A) Epitheliochorial
B) Endotheliochorial
C) Hemochorial

Answer 15

A) Bovine, Caprine, Equine, Ovine, Porcine
B) Cats and dogs
C) Primates and rodents

Question 16

Why is it recommended to withdraw altrenogest after 320 d of gestation?

Answer 16

Altrenogest, a synthetic progestagen, has been shown to cause a reduced neutrophil to lymphocyte ratio in foal blood.

Question 17

If a premature delivery is imminent, what should be given to the mare in attempts to stimulate and accelerate fetal lung maturation through enhanced surfactant production?

Answer 17

Corticosteroids

Question 18

What are the three criteria to inducing labor in a mare?

Answer 18

1) Past 320 days of gestation
2) Good quality colostrum in the udder
3) Softening of cervix

Question 19

What are ways of inducing labor in a mare?

Answer 19

Slow CRI of oxytocin at 1 IU/min, resulting in delivery within 20-40 minutes.

10 to 20 IU of oxytocin IM or IV, every 10 minutes

Question 20

What are the systems greatly affected in a foal with perinatal asphyxia sydrome?

Answer 20

Nervous system, renal system and gastric system

Question 21

At what heart rate or arrythmia should cardiac compressions occur during resuscitation?

Answer 21

< 40 bpm or asystole