General Parturition, Obstetrics, and Fetotomy

Lectures 2 and 3

In domestic species, the ____ initiates parturition.

fetus

What hormone must decrease for parturition to occur?

progesterone

In domestic species, what are the 3 stages of parturition (in order of occurrence)?

1. initiation of myometrial contractions (removal of “progesterone" block”)

2. expulsion of the fetus

3. expulsion of the fetal membranes (placenta)

Describe the mechanism of parturition.

maturation of the fetal hypothalamic hypophyseal adrenal axis

increased sensitivity of the fetal adrenal glands to ACTH

increased fetal corticoids from the adrenal cortex

activation/conversion of placental enzyme systems (decreasing progestagens, increasing estrogen)

relaxin —> relaxation of pelvic ligaments

prolactin —> part of the initiation of lactation

uterine activity —> up regulation of oxytocin receptors in endometrium and release of prostaglandin F2 alpha

Which stage of parturition is described:

• duration varies by species

• myometrial contractions

• restlessness, anorexia, abdominal discomfort, increased pulse and respiration, nesting and/or isolation from others, shifting weight, arched back, elevated tail, colic like signs can be present

• in mare, ewe, and cow the fetus rotates itself in preparation for exit —> initiates Ferguson’s reflex

• dilation of cervix

Stage 1 - initiation of myometrial contractions (removal of the progesterone block)

What is the positive feedback neuroendocrine reflex comprising the self-sustaining cycle of uterine contractions initiated by pressure on the cervix or vaginal walls which stimulates the release of oxytocin, which stimulates the uterine contractions, which pushes the fetus into the cervix/cervical canal causing more pressure thus more oxytocin release, and so on?

Ferguson’s reflex

Which stage of parturition is described:

• fetus enters cervical canal

• rupture of chorionic membranes (chorioallantois)

• active controlled abdominal pressing

• delivery of the fetus

Stage 2 - expulsion of the fetus

Which stage of parturition is described:

• time to expulsion varies by species

• expulsion of fetal membranes

Stage 3 - expulsion of fetal membranes

What is defined as the relationship of the spinal axis of the fetus to that of the dam and the portion of the fetus that is entering the birth canal?

presentation

What is defined as the anatomic relationship of the dorsum of the fetus relative to the maternal pelvis?

position

What is defined as the anatomic relationship of the fetal extremities to its own body?

posture

What is PPP?

presentation

position

posture

Describe presentation, position, and posture for normal delivery (parturition) in bovine and equine.

cranio-longitudinal (presentation)

dorso-sacral (position)

head and forelimbs extended (posture)

Describe presentation, position, and posture for normal delivery (parturition) in canine.

cranio or caudo-longitudinal (presentation)

dorso-sacral (position)

head and limbs extended (posture)

What is defined as difficulty giving birth?

dystocia

Is dystocia more common among primapara (first baby dam) or multipara (dam that has already had one or more babies)?

primapara

Which domestic species poses the highest incidence of dystocia?

cattle

Which domestic species poses the lowest incidence of dystocia?

cats

What is the “theriogenologists mantra”?

be clean

be gentle

use lots of lube

What lubricant is fatal if introduced into the abdomen, therefore you need to think before using it in case a dystocia turns into a C section?

J-Lube (Polyethylene polymer)

What is the most common lubricant used that is available in powder or liquid form?

Methylcellulose lubricant

True or False: Removal of hair is not indicated for arthrocentesis with sharp injection needles, but is recommended when using spinal needles with stylets.

True

Should you ship a horse that is still numb from an epidural?

NO, they will fall in the trailer

Wait until it wears off

What is defined as the process by which the fetus is restored to a deliverable fashion?

mutation

What is defined as pushing the fetus out of the maternal pelvis into the uterine cavity (maternal abdomen) to enable correction of the abnormality and allow more space to mutate?

repulsion

What is defined as turning the fetus on its longitudinal axis?

rotation

What is defined as turning the fetus on its transverse axis into a cranial or caudal presentation?

version

List methods of correction and delivery.

assisted vaginal delivery (AVD)

controlled vaginal delivery (CVD)

fetotomy

cesarean section

Describe the abnormality in this image.

cranoi-longitudal

dorso-sacral

right forelimb flexed at the carpus

known as leg retained

Describe how to mutate a fetus with “leg retained” into a deliverable position.

bring limb up the midline by looping rope at fetlock and pushing carpus back while pulling the fetlock forward to get the hoof into the vaginal canal with the other limb

can also pull limb forward by hand

ensure protection of uterus

Describe the abnormality in this image.

caudo-longitudinal

dorso-sacral

right hindlimb flexed at tarsus, hock, and stifle

Describe the abnormality in this image.

cranio-longitudinal

dorso-sacral

head extended

both forelimbs flexed at the shoulder

Describe the abnormality in this image.

cranio-longitudinal

dorso-sacral

head and forelimbs extended

hindlimb flexed at the hip

Describe the abnormality in this image.

cranio-longitudinal

dorso-sacral

head and forelimbs extended

hindlimbs flexed at the hips

Describe the abnormality in this image.

cranio-longitudinal

dorso-sacral

head flexed to right of fetus both forelimbs extended

List methods to hold onto the head of the fetus.

nose hold

fingers in mouth (intermandibular space)

eye socket hold (blunt eye hooks)

noose around lower jaw

noose around head that passes through opening of mouth

What abnormality (shown in the image) is the same as flexed neck, but impossible to correct since the spine is fixed in this position, meaning it is not agreeable with life and may require fetotomy or C-section?

wry neck

Describe the abnormality in the image.

caudo-longitudinal

dorso-sacral

hind limbs flexed at the hip

known as breech

Describe the abnormality in this image.

caudo-longitudinal

dorso-sacral

hind limbs flexed at the hock and stifle

known as hock presentation

Why is it important to pay attention to which way the feet are pointing on presentation?

normal presentation is front feet will be pointing down and fetus is dorso-sacral

if fetus backward and upside down —> feet will still be down even if it is hindlimbs first

owner’s cannot tell front limb from rear limb!

Describe the abnormality in this image.

caudo-longitudinal

dorso-pubic

hind limbs extended

When results from ventral displacement of the uterus and folding of the uterus/cervix as shown in the image?

ventro-transverse presentation

What abnormal presentation is shown in the image?

dorso-transverse

Traction on both forelimbs simultaneously when pulling a calf or foal often results in what?

shoulder lock

What should you do to avoid causing shoulder lock when pulling a calf or foal?

traction on one forelimb and then the opposite forelimb should be applied in a seesaw motion

What should be done during fetal extraction to prevent hiplock in cattle?

rotate calf as fetal head emerges from vulva

What is the most common fetotomy performed?

partial fetotomy

What are the two different types of fetotomy?

partial fetotomy

full fetotomy

A full fetotomy is how many cuts total?

5-6

List the cuts for a full fetotomy.

decapitation or cervical (verterbral amputation) (1 cut)

amputation of forelimbs (2 cuts) —> subcutaneous or percutaneous

detruncation (may be done in 1 or 2 cuts) —> transection, evisceration, destruction of teh rib cage, lumbar transection

division of the pelvis (1 cut) —> divide diagonally

What is the difference between a partial fetotomy and full fetotomy?

partial fetotomy can be as little as one cut, it is anything not considered a full fetotomy

a full fetotomy is 5-6 specific cuts