Lecture 5: Bovine Eutocia, Dystocia, Obstetrics, Fetotomy, and C-section

eutocia is

the normal delivery of a fetus

pre-partum changes

• udder edema and milk production (1-2 weeks prior)

• relaxation of the pelvic ligaments (raised tail head) → sacrosciatic and sacrotuberous ligaments

• elongation and softening of the vulva

• dilation and opening of the cervix just prior to parturition

• melting of the cervical plug → appears at the vulva

stage 1 of bovine parturition is initiated by the

fetus → cortisol

bovine parturition stage 1

• usual duration of 1-6 hours

• restlessness, anorexia, signs of abdominal discomfort, increased pulse and respiration, nesting and/or isolation from others, shifting weight, arched back, elevated tail

• fetus rotates itself

• initiation of ferguson’s reflex

• dilation of the cervix

• dropping or availability of colostrum/milk in the teats

initiation of contractions of myometrium for short periods in stage 1 of bovine parturition

• increasing in frequency and duration as second stage approaches

• contractions begin in the apex of the pregnant horn in monotocous species or cranial to the most caudad fetus in polytocous species

what marks the end of stage 1 and beginning of stage 2 for bovine parturition?

rupture of the chorioallantoic membrane → breaking water

bovine parturition stage 2

• begins with rupture of the chorioallantois

• ends with delivery of the fetus

• duration is 30-60 minutes in cows (may be up to 4 hours in heifers)

• active straining and expulsion of fetus

• rupture of the amnion

• ferguson’s reflex in full force

• heifers may not strain if in pain or not making progress

• dam lies in sternal recumbency, then lateral for delivery

bovine parturition stage 3

• expulsion of the fetal membranes → usually not considered retained until greater than 12 hours

• dam grooms calf

• dam may eat fetal membranes (afterbirth)

dystocia

• more common in primipara than multipara

• cattle have highest incidence

  • most common cause in cattle is FETAL MATERNAL MISMATCH

fetal maternal mismatch

• fetal cause because the fetus is too big

• caused my mismanagement

maternal causes of dystocia in cattle

• primary uterine inertia

• secondary uterine inertia

• abnormalities of the birth canal

fetal causes of dystocia in cattle

• fetal oversize → fetus too big to go through pelvis

• abnormal presentation, position, and/or posture

• fetal monsters → schistosomus reflexus, peresomus elumbus, curly calf syndrome, hydrocephalus, arthrogryposus, anasarca

primary uterine inertia

• dam never progresses to stage 2 of labor

• few weak abdominal contractions

• cervix usually dilated on examination

secondary uterine inertia

exhaustion of myometrium after prolonged attempts to deliver fetus

abnormalities of birth canal

• inadequate size of pelvis

• pelvic deformities

• incomplete cervical dilation

• neoplasms

• persistent mullerian ducts

what is this?

fetal monsters

what is this?

perosomus elumbus

what is this?

anasarca (water baby)

what is this?

schistosomus reflexus

what is this?

curly calf

feto-maternal mismatch/fetopelvic dysproportion

• etiology is management-related

• most common cause of cow dsytocia

• calf is too big

• management issues → heifer bred too early, small heifer, bred to a bull that throws large calves rather than a heifer bull, dam is obese

clinical management of bovine dystocia

• asking questions → how long has she been trying to calve?, history of dystocia on this farm?

• restraint

dystocia vaginal exam

• clean perineum with soap and water

• assess fetal viability

• assess fetal number

• PPP

• estimate fetal size

• develop a delivery plan

• epidural

• lots of lube

fetal extraction

• after mutations are completed, the fetus is in a favorable position and fetus is deliverable size-wise

• hand delivery → no more than 2 adults on chains, traction is directed in an arc like fashion

• mechanical fetal extractors aka calf-jack

what should you do when the cow pushes?

pull or push down

two people pulling a calf exerts about

400 psi

calf jack exerts about

2000 psi

episiotomy

• incise vulva at 10 and 2 position

• fetus fits through pelvic inlet just tight at level of vulva

delivery with traction is not possible so

• fetotomy → partial or full

• C-section

fetotomy is not

a last resort

indications for fetotomy

• dead fetus → if fetus is not dead and you can euthanize, this still remains a possibility

• uncorrectable fetal malposition

• delivery by traction is not working

• feto-maternal mismatch (large fetus)

• certain fetal monsters/ankylosis

• incomplete cervical dilation

true or false: a fetotomy should never be performed on a live fetus.

true

fetotomy requirements

• adequate space between uterine wall and fetus

• ± with grossly oversized fetus or emphysematous fetus

• want to be able to remove parts with easy traction

fetotomy is most commonly done in a

standing cow

partial fetotomy

• most common fetotomy

• amputation of the head, neck, or limbs

• fetal malposture → wry neck

• fetal oversize

fetotomy aftercare for bovine

• ± lavage uterus

• systemic antibiotics

• anti-inflammatories

• IV or oral calcium

• ± IV fluids

• ecbolics → oxytocin, PGF2alpha

C-section characteristics

• more expensive and traumatic

• increased recovery time and aftercare

• potential impact on future fertility

• requires assistance

• may take more time

fetotomy characteristics

• reduced expense and trauma

• shorter recovery time and less aftercare

• less impact on future fertility, milk production

• especially in a partial fetotomy

indications for C-section

• vaginal delivery unsafe for dam or fetus

• usually a live fetus

• inadequate room to place fetotome

• oversized, large fetus

• sometimes necessary just to save the dam’s life

90% if C-sections are due to

• fetal oversize → pre and post emphysematous changes

• incomplete cervical dilation of cervical closure on a dead fetus

• irreducible uterine torsion

• fetal deformity

• errors of fetal PPP

C-section considerations

• dam → behavior, ability to stand, intended use of animal

• environment → dirty or clean

• restraint

C-section surgical approach

• several surgical approaches to choose from

• case based

• ask questions like is the calf alive or dead?, calf malformed?, physical conditions of the dam, etc

• preference and experience of the surgeon

advantages of ventral midline C-section approach

• best surgical exposure

• least abdominal contamination

• best cosmetic effect

disadvantages of ventral midline C-section approach

• restraint

• failure of suture line catastrophic

• dorsal recumbency

C-section ventral midline

• cast, oblique dorsal recumbency

• general anesthesia rarely used or needed

• line block

• ace + butorphanol

• epidural reduced straining

• big skin incision, linea alba, reflect greater omentum

• exteriorize uterus, incise uterus at greater curvature, cut from tip of toe to tip of hock

why should you incise the uterus at the greater curvature?

less blood supply

uterus closure for ventral midline C-section

• inverting pattern, #1 or #2 absorbable, non-penetrating, bury knots

• utrecht (most common)

• cushing or lembert

• do not include placenta

oxytocin for C-section

• should be given to promote uterine contractions

• before or after uterine closure

• surgeon preference on when

post-op care for c-section

• stall rest

• ± antibiotics

• ecbolics (oxytocin and/or PGF2alpha)

• analgesia + NSAIDs

advantages of standing flank c-section

• restraint easy for healthy animal

• closure simplified

• surgeon comfort

disadvantages for standing flank c-section

• less exposure

• peritoneal contamination

• standing animals can go down

standing flank c-section

• be careful with sedation

• local → distal or proximal paravertebral block, inverted L, line block

• left flank most common

• right flank if there is a presentation or anomaly issue that makes it easier

advantages of bovine recumbent flank c-section

• moderate exposure

• closure may be more secure

disadvantages of bovine recumbent flank c-section

• hard to exteriorize

• restraint

• careful for contamination