dystocia Flashcards by Madeleine Gauthier

what is dystocia in cattle?

difficult or prolonged birth that may or may not require human assistance

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describe the 3 stages of parturition in cattle briefly

stage 1: relaxation and dilation of the cervix, rupture of the chorioallantois and membrane

stage 2: passing of the fetus through the birth canal

stage 3: expulsion of fetal membranes

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tell me how hormones prime the cow for onset of parturition

fetal adrenal glands release cortisol
increase 17alpha hydroxylase in placenta
decreases progesterone
converts pregnenolone to estrogens
increasing PGF2alpha myometrium contractions

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how long does stage 1 of parturition last in the cow?

8-12 hours

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during stage 1 parturition in the cow, how is dilation of the cervix achieved?

decreasing cervical tone, absence of progesterone, mechanical pressure form fetus

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during stage 1 parturition in the cow, how are myometrial contractions initiated

pressure synapse release oxytocin

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how long does stage 2 parturition last in the cow?

1-4 hours

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during stage 3 parturition in the cow, how does detachment of the placenta occur?

via vasoconstriction and myometrial contractions, which dislodge the chorionic villi from the crypts

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how long does stage 3 parturition last in the cow?

12 hours

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true or false: a stage 3 lasting >24 hours in the cow is considered pathologic

true

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briefly tell me fetal blood circulation in utero

umbilical vein –> portal vein (ductus venosus) –> caudal VC –> RA –> LA foramen ovale –> LV –> aorta –> umbilical arteries –> pulmonary artery (ductuc arteriosus) –> aorta

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tell me how fetal blood circulation changes with rupture of the umbilical cord?

rupture of umbilical cord –> asphyxia –> gasping reflexes –> increased peripheral vascular resistance –> lung inflation –> increased O2 tension –> ductus arteriosus closes –> increase BP –> closure of foramen ovale

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rupture of the umbilical cord leads to a ________ (acid base dysfunction)

transient mild mixed acidosis

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rupture of the umbilical cord leads to a transient mild mixed acidosis. tell me the 2 components of a mixed acidosis and why it’s caused in this case

metabolic acidosis: anaerobic glycolysis initiated by poorly perfused tissues

resp acidosis: asphyxia and build up of CO2

lactic acidosis caused by anaerobic glycolysis and poor tissue perfusion

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what are the problems with acidosis at birth?

increased risk of failed transfer of passive immunity
increased risk of pre-weaning morbidity and mortality

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what are the behavioural indicators of dystocia?

restlessness
prolonged lying time
longer duration of tail elevation
reduced abdominal contractions
prolonged time b/t visualization of amniotic sac to birth of the calf

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true or false: dystocia is more common in beef cattle than dairy cattle

false!
incidence in beef cattle: 5-15%
incidence in dairy cattle: 15-30%

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tell me some dam risk factors for dystocia

heifer
high birth weight
low BCS as a yearling dam
low or high BCS at calving
mineral deficiencies
confinement

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tell me some neonate risk factors for dystocia

male –> larger body dimensions and higher birth weight
twins –> malpresentation or malposture
high birth weight –> larger –> fetal maternal size mismatch

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tell me some ways to decrease the risk of dystocia

heifer selection
dam nutrition
sire selection for birthweight and calving ease
pelvic abnormalities

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name 3 causes of dystocia that are maternal in origin

primary uterine inertia
secondary uterine inertia
abnormalities of the birth canal

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name 3 causes of dystocia that are fetal in origin

abnormal P’s (presentation, posture, position)
large offspring (fetal oversize or large offspring syndrome)
fetal monsters (deformities)

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what is primary uterine inertia?

failure of the myometrium to contract

what is secondary uterine inertia?

exhaustion of the myometrium after a prolonged parturition

what causes primary uterine inertia?

- **overstretching of the uterus by multiple fetuses** - defect in the myometrium - defect in the parturient hormones - **muscular atony caused by post parturient hypocalcemia**

tell me some abnormalities of the birth canal that can cause dystocia.

- small maternal pelvis - pelvic deformities - **incomplete dilation of the cervix** - remnants of the mullarian ducts - **uterine torsions 5-10%**

what are the causes/risk factors of uterine torsion?

- multiple fetuses - walking up hills - poor muscle tone - enlarged rumen - breed = brown swiss

how do you tx uterine torsions?

- "plank in the flank" --> laterally recumbent animal has plank on flank to hold uterus still, person stands on plank and animal is rolled in the direction of the torsion - c-section - detorsion rod

50% of dystocias are caused by ____?

fetal maternal size mismatch

the odds of fetal maternal size mismatch causing dystocia increase by 13x by every _____kg increase in birthweight

fetal maternal size mismatches are more common in _____

heifers

fetal material size mismatches are the result of what?

mismanagement of heifers and bull selection

what are the 3 P's?

presentation, position, posture

what is presentation? what is normal?

relation of the spinal axis of the fetus to the dam's axis *which part of the calf is being presented for delivery* anterior, posterior, transverse normal: anterior

what is position? what is normal?

relation of the dorsum of the fetus to the quadrants of the material pelvis dorsosacral dorsopubic dorsoilliac normal: dorsosacral

what is posture? what is normal?

relation of the fetal extremities to its own body head ventroflexed carpal flexion hip bilaterally flexed (breech) normal: both front legs and head presented in the birth canal

list the 3 P's in order of most likely to cause dystocia to least likely

posture presentation position

when should you intervene in a cow birth?

- not making progress every 30-60 mins - abnormal PPP (3 p's) - prolonged gestation date (only if accurate!)

what are the 3 therio rules? like very general

be clean, be gentle, and by god use LOTS AND LOTS OF LUBE

what equipment do you need in a dystocia case?

- bucket of warm water - disinfectant - lube (not J-lube) - OB sleeves - OB chains, handles, head snare, calf jack - halter/ropes

what do you do to the cow to get ready to help with a dystocia?

- restrain - tie tail - rectal exam - clean perineum - vag exam with OB sleeves and lube

talk me through a vag exam of a cow with dystocia

1. enter vag, ID cervix - note if fully dilated, obstructions, etc) 2. enter uterus 3. ID calf w/ 3 P's 4. ID if calf alive or dead - pull on tongue, pinch toes, palpebral reflex, anal reflex

tell me the broad steps of dealing with a dystocia case

1. restrain, tie tail, etc 2. rectal exam, clean perineum 3. vag exam 4. mutation 5. make sure calf can fit 6. get ready to pull 7. PUUUULLLLLLLLL!!!!!!

what is mutation in terms of helping with dystocia?

fetus is restored to normal presentation, posture, and position by repulsion, rotation, version, or extension of extremities

what is repulsion when dealing with mutation?

push the fetus out of the maternal pelvis into the uterine cavity

what is rotation when dealing with mutation?

turning the fetus on its longitudinal axis to bring it to dorsosacral position

what is version when dealing with mutation?

turning the fetus on its transverse axis into anterior or posterior position unlikely to correct usually results in C-section

how can you make sure the calf will fit in the birth canal?

head and legs should be able to be advanced into the birth canal hand should be able to go around calf when positioned in the birth canal

how do you get ready to pull a calf out of the vag?

2 limbs ± head are in normal position and belong to the same calf apply OB chains above fetlock with half hitch below

how do you successfully and properly pull a calf outta its momma?

- pull only when cow contracts or pushes - relax when cow relaxes - pull one limb at a time (see-saw) - once head and front limbs are out and chest is in birth canal, rotate calf 45 degrees to prevent hip lock

tell me some *fun* little helpful tools and tricks to assisting with dystocia

- epidurals prevent contractions - oro-tracheal tube prevents abdominal contractions - epi IM can relax ute ute to repulse and reposition - casting cow down in lateral recumbence opens pelvis

what do eye hooks do?

direct the head

what does a head snare do?

directs the head

tell me some other options for calf removal other than pulling that bitch out of the vag

- C section - fetotomy (if its dead already, obvi)

post delivery in the cow, what should you address?

- "spares and tears" - pain mitigation - ABs - ± ecbolics

tell me important things to do right after calf leaves birth canal (post-calving calf care)

- sit calf in sternal recumbency - ABC (airway, breathing, circulation)

how do you assess ABC in a newly born calf?

A: clear airway, resuscitation B: rub vigorously, straw up nose C: check heartbeat, give resuscitation drug