Obstetrics

Question 1

What is the first step to successful delivery assistance? What should producers/owners do?

Answer 1

recognizing a normal delivery

triage pregnant animals

Question 2

What triggers the beginning of parturition?

Answer 2

uterine crowding causes increased fetal ACTH, which initiates a cascade of hormonal changes

• fetus decides the date, dam decides the time
• larger litter = more crowding = shorter gestation
• singleton/mummy = no crowding = will not initiate parturition

Question 3

What are the 3 stages of parturition?

Answer 3

1. preparatory - uterine contraction, rotted fetal position (equine), chorioallantois/chorioamnios rupture
2. fetus enters the vagina and is expulsed
3. expulsion of fetal membrane

Question 4

What is Ferguson’s reflex?

Answer 4

neuroendocrine reflex caused by the straining forces of the fetus against the cervix and cranial vaginal, inducing the release of additional oxytocin

Question 5

What tends to increase the risk of a foal failing to survive during parturition?

Answer 5

every 10-minute increase in duration of labor at stage 2 beyond 30 mins

Question 6

Parturition, differences in species:

Answer 6

Question 7

In what 2 situations should intervention during parturition in mares be done?

Answer 7

1. premature placental separation (red bag)
2. foal not born within 20 mins after a mare releases allantoic fluid

Question 8

In what 3 situations should intervention during parturition in cows be done?

Answer 8

1. non-progressing parturition stage 1 (uterine torsion)
2. > 2 hr after the first appearance of the amnion at the vulva
3. no progress observed within a 30 min interval

Question 9

In what 3 situations should intervention during parturition in bitches/queens be done? In bitches especially?

Answer 9

1. no delivery of pup/kitten within 4 hours after the beginning of stage 2
2. exhibit strong contraction for >30 mins without producing pup/kitten
3. prolonged intercal (>2 hr) between delivery of pup/kitten

green vaginal discharge without delivering the first pup - obstructive dystocia, C-section recommended

Question 10

In what 2 situations should intervention during parturition in small ruminants be done?

Answer 10

1. fetal membranes at vulva for >3 hr without delivery - digital examination shows an incompletely dilated cervix (ringworm) –> C-section, dilation not helpful
2. 30 min rule - examine 30 mins after the breaking of the chorioallantoic membrane and after delivery to look for an additional fetus

Question 11

In what situation should intervention during parturition in camelids be done?

Answer 11

cria not born within 20 mins after the beginning of stage 2

• like mare, has a short stage 2

Question 12

In what situations should intervention during parturition in sows be done?

Answer 12

piglet interval >2 hrs

Question 13

What is the difference between superfecundation and superfetation?

Answer 13

successive fertilization of two or more ova by different sires –> more common in feral situations and in swine

successive fertilization of 2 or more ova of different ovulations, resulting in presence of embryos of unlike ages

Question 14

What is the difference between ecbolic and tocolytic agents?

Answer 14

increase uterine contractions (PGF2a, oxytocin)

inhibit uterine contractions
- N-Butylscopolammonium (Buscopan) - anticholinergic
- Clenbuterol - anticholinergic
- epidural anesthesia

Question 15

How is fetal disposition described?

Answer 15

• Presentation
• Position
• Posture

Question 16

What is fetal presentation? What are the 3 terms used to describe it?

Answer 16

orientation of the fetal spinal axis to that of the dam and the portion of the fetus that enters the vaginal canal first

1. LONGITUDINAL - anterior vs posterior, fetal spine parallel to dam’s
2. TRANSVERSE - ventral vs dorsal, fetal spine not in like with dam’s
3. VERTICAL - ventral vs dorsal, fetal spine is perpendicular to dam’s (dogsitting)

Question 17

How is fetal position described?

Answer 17

LONGITUDINAL - based on the surface of the maternal birth canal to which the fetal vertebral column is applied OR the relationship of the fetal dorsum to the quadrant of the dam –> dorsal (dorso-sacral), ventral (dorso-pubic), left/right lateral (left/right dorso-ilial)

TRANSVERSE - relationship of the fetal head to the quadrants of the dam –> right/left cephalo-ilial

Question 18

What is fetal posture?

Answer 18

disposition of the movable appendages of the fetus, involving flexion or extension of the neck or limb joints

• lateral flexion of the neck
• hock flexion

Question 19

Fetal presentation, position, and posture:

Answer 19

Question 20

What are 4 possible methods of obstetric manipulation to aid parturition?

Answer 20

1. REPULSION - fetus repelled from the pelvic canal to increase space in the uterus to correct malposition
2. MUTATION - manipulation of extremities with correction of postural abnormalities
3. ROTATION - turning fetus on its longitudinal axis (hip-lock during calving)
4. VERSION - manual changing of the polarity of the fetus with reference to the mother to correct transverse presentation –> head and forelimbs are repelled into the uterus while the hindquarters are pulled into the pelvic canal

Question 21

What are 7 causes of dystocia?

Answer 21

1. fetal materal disproportion
2. faulty fetal disposition
3. hereditary - schistosomus reflexus, hydrocephalus, anasarca
4. nutritional - obesity (pelvic canal obstructed by fat
5. infectious - dead fetus
6. traumatic - hernia, rupture of prepubic tendon, tear of abdominal muscles
7. uterine inertia

Question 22

Causes of dystocia:

Answer 22

Question 23

How are small animal dystocias most commonly resolved? What other method are commonly used in large animals?

Answer 23

medical

• mutation and rotation
• forced extraction
• fetotomy
• C-section

Question 24

What restraints are recommended for assisted vaginal delivery and controlled vaginal delivery?

Answer 24

minimal - light sedation, epidural anesthesia, NEVER deal with it in a chute

general anesthesia

Question 25

Before the decision of how to resolve dystocia, what should be done?

Answer 25

- check for fetal viability and distress - U/S for fetal heartbeat, radiographs for intra-fetal gas accumulation or abnormal skeletal arrangements, reflexes (suckle, anal tone, sublingual pulse) - check for uterine torsion

Question 26

Before deciding on medical treatment of dystocia, what 2 things should be done?

Answer 26

1. radiographs - determine fetal number as well as malposition or fetal-maternal mismatch 2. U/S - fetal viability and presence of distress (if obstruction is present, do NOT give ecbolics)

Question 27

What are the 2 major medical treatments of dystocia?

Answer 27

1. oxytocin - NEVER given with obstruction, microdoses recommended, move onto C-section if nothing is delivered with 3 doses repeated in 15-30 mins (SQ, IV, IM) 2. calcium solutions - concurrent cardiac monitoring for arrhythmias, SQ given 5 mL per location every 4-6 hours

Question 28

What lubricants are commonly used for resolving dystocia? What is avoided?

Answer 28

methylcellulose-based polyethylene polymer-based (J-Lube) --> fatal peritonitis in mares (administered through sterile nasogastric tube and pump)

Question 29

What part of anatomy predisposed cows to dystocia? How is this approached?

Answer 29

oval shaped pelvic canal - alternate by pulling one limb at a time to decrease diameter of shoulders - hip lock - rotate calf 45 degreed to decrease diameter across the pelvis

Question 30

How is recumbency used to resolve dystocia?

Answer 30

changed the angle of the pelvis to increase the functional diameter of the pelvic canal - NOT done in chute, can't get the cow out

Question 31

How can it be determined if a fetus is in anterior or posterior presentation if a limb can be observed?

Answer 31

FORELIMB - first two movable joints (fetlock and carpus) flex in the same position HINDLIMB - first two movable joints (fetlock and hock) flex in the opposite direction

Question 32

What are possible causes of no palpable limbs or both forelimb and hindlimb seen in cases of dystocia?

Answer 32

NONE - true breech (posterior longitudinal presentation with a bilateral hip flexion), schistosomus reflexus, dorso-transverse presentation (dog sitting) BOTH - multiple fetuses, schistosomus reflexus, ventro-transverse presentation

Question 33

Repositioning unilateral carpal flexion:

Answer 33

retropulse fetus to gain space then pull on flexed carpus

Question 34

Repositioning unilateral shoulder flexion:

Answer 34

Question 35

How is a forced extraction done correctly? What tools can be used?

Answer 35

apply traction during abdominal contractions of the dam and constantly monitor progress - hands - clamps/forceps - OB chains, straps - applied above and below fetlock - head snare - behind ears, wedge in oral cavity - mechanical extractor - calf jack

Question 36

How are OB chains put on correctly?

Answer 36

place a loop above the fetlock and a half hitch around the pastern - tie over the front to avoid pressure on tendons - shorter chain = more power

Question 37

What are 3 pros and 3 cons to performing fetotomy for dystocia?

Answer 37

PROS - avoids expense and risks of C-section, may prevent further trauma to dam through excessive traction, reduces the size of the fetus CONS - lacerations to genital tract, time-consuming, infections to obstetrician or dam if fetus is septic, necrotic, or emphysematous (dislocate joint for delivery, avoid breaking bones!)

Question 38

What is a complete fetotomy?

Answer 38

dismembering an oversized fetus with 5-6 cuts - not always necessary for delivery

Question 39

What kind of fetotomy is recommended in mares? If the foal is dogsitting or breeched? Why?

Answer 39

partial --> use one cut to remove the head or one foreleg more complicated cuts, consider a C-section MM of mare's vaginal and cervix are easily abraded and can form adhesions

Question 40

What post-dystocia care is necessary?

Answer 40

- check for additional fetuses - examine genitourinary tract for laceration, hemorrhage, and infection - recto-vaginal fistula, perineal laceration, necrotizing vaginitis, metritis - examine fetal membranes, appropriate retained placental therapy

Question 41

What are 4 risk factors for perineal laceration?

Answer 41

1. first delivery 2. unopened Caslick's suture 3. dystocia - foot-nape position 4. delivery of large fetus

Question 42

What are the 3 degrees of perineal lacerations?

Answer 42

1st DEGREE = skin and MM of dorsal commissure 2nd DEGREE = musculature of constrictor vulvae and perineal body 3rd DEGREE = complete disruption of vaginal vault and/or roof of the vestibule, rectal floor, and anal sphincter, and perineal septum/body

Question 43

What are 3 membrane removal techniques used in mares?

Answer 43

1. uterine lavage 2. Burns' technique - chorioallantois is distended with dilute povidone-iodine or saline solution for 15 to 30 minutes to facilitate release of microcotyledons from the endometrium 3. umbilical vessel infusion