What is gestation length in Bos Taurus?
280 days +/-
Cows carrying twins tend to go into labor when?
2 weeks early, sometimes dystocia
What hormones relax pelvic ligaments in preparation for parturition?
Relaxin and estrogens
What hormones soften the cervix?
Relaxin and PGE
What is different about the bovine cervix?
It is cartilaginous so softening is very important
What ultimately determines when parturition will occur?
Fetal cortisol, all cow hormones respond to fetal signal. (rising PGF2A, and estrogen, falling P4)
When does the fetus get into position for parturition? what is that position?
When myometrial contractions occur. Anterio-dosal most commonly (dorsum of fetus is dorsal in uterus, front feet toward cervix.)
What ends the first stage of parturition?
rupture of the chorioallantois
Normal stage 2 time frame?
Cows 0.5-2 hrs
Heifers: 2 - 4 hrs
How long after expulsion of calf should we see the fetal membranes?
Less than 12 hours.
Greater than 12 hours = retained placenta. But she could have eaten it while you weren’t watching
Under what conditions can you induce parturition?
If you know the breeding dates (its not common to do this)
How do we medically induce parturition?
Give Dexamethasone and Cloprostenol (PGF2A) 2 days before you want them born. - most predictable parturition timing.
Why don’t you want to use natural PGF2A (dinoprost) to induce parturition?
High rate of retained placenta and dystocia
When should you intervene in stage one labor?
no progression after 4 hrs. bleeding, hypocalcemia, uterine torsion, bilateral hop flexion
cloned embryos are at risk of dystocia due
large size
hydrallantois
What are methods to prevent dystocia?
Bull selection for calving ease
Nutritional management
Pelvimetry
What are the 5 factors that are related to gestation difficulty
Gestation length Parity (how many times calved) Season Nutrition Genetics
When coming onto a dystocia case, what is the first thing you should look at?
Is she even pregnant? Transrectal exam
Before a vaginal examination, what should we do for analgesia?
Caudal epidural: 1 mL 2% lidocaine/100kg BW
what type of lube should we use?
Not J-Lube…
Normal Presentation of a calf in canal at birth
Longitudinal cranial or caudal
Normal Position of calf at birth
Dorso-sacral (fetus - mom pelvis)
Normal posture of a calf at birth
Extended limbs
What are ways you can check for fetal viability, and what should you keep in mind?
Interdigital claw reflex (pinch)
Swallowing reflex
Eye reflex
Be careful with false negatives, may just be hypoxic and still alive
What is a method to diagnosis uterine torsion?
Transrectal palpation you feel for the broad ligaments *most common is counterclockwise
What is the most reliable clinical sign that a cow has a uterine torsion?
- **Failure to progress to the second stage of labor
- *Raised tail head
- Restlessness
How do you manage uterine torsion?
Rolling if you have enough people, c-section if not. Lay her down on side the torsion has twisted to (so left side if it is a counter clockwise torsion)
3 types of manipulations to restore the fetus to normal position for birth
Repulsion
Rotation
Version or extension of extremities
When would you use version?
if the fetus is in transverse presentation, but not possible in ventral transverses
If the head has not moved spontaneously into the pelvis, or the forelimbs are crossed, what should we be thinking?
Likely vaginal delivery is impossible (too big)
What are the consequence’s if you place obstetrical chains on a fetal limbs incorrectly?
Degloving, fractures
How can you maximize the pelvic diameter when pulling a large calf?
Rotate the body to a 45 degree angle, largest diameter of the pelvis
How do you know if vaginal delivery is possible with posterior presentation?
If the hocks can be exteriorized with simple force
What is the surgical approach 90% of the time for c-section?
Left- paralumbar
Where do you cut for c-section
caudal third
What does Dr. Tibary recommend for instrument use for cutting?
Scalpel on skin, metzenbaums on anything deeper
Once in the peritoneal cavity, what do you do first?
wet sterile sleeves check condition of cavity, uterus, check for lacerations, torsion, tone of uterus
What part of the uterus do you exteriorize?
the tip of the uterine horn by grasping a fetal limb
Where is the incision into the uterus made?
the greater curvatures (tip of horn extended caudally)
How many layers do you close the uterus?
2 layers
1: continuous
2: inverting pattern (intramurally), make sure each suture is pulled tightly
For the abdominal incision what direction do we start?
ventral commissure: gives better visualization and allows you to push air out of abdomen right before closure.
What is included in the first abdominal closure layer?
Peritoneum, transverse and internal oblique
Second abdominal incision layer?
External oblique, subcutaneous tissue
What pattern do we use to close the skin?
Ford interlocking (4 cm from ventral edge leave room for cruciate - drainage)
Calf resuscitation, what do we need to do for the calf after they are out?
suction/hand, place calf in sternal, rub for stimulation of respiration, ET tube if needed, MAINTAIN body temp (101), make sure it gets adequate early colostrum
How do we assess calf vitality?
should lift head in 3 min
be sternal in 5 min
Attempt to stand in 30 min
Stand spontaneously w/in 60 - 90 min
What do we dip the umbilical cord with?
Chlorhexidine
How do we know colostrum quality is good?
Should have > 50 g/L IgG on a refractometer
Who has better colostrum, beef or dairy, young or old?
Beef, middle aged
colostrum absorption timeframe?
By 6 hours after birth 50% of absorption ability is lost
FPT = IgG < 10 mg/mL
What are life-threatening dystocias?
Metritis and toxic shock
Downer cow
Uterine prolapse
Uterine hemorrhage
Cow 7 days post partum, anorexic, fever, tachycardia, tachypnea, dehydrated, dark brown foul smelling discharge from vagina, rumen atony. What are your 3 big differentials?
Septic metritis
Toxic mastitis
Peritonitis
What is the most common predisposing factor for uterine prolapse?
Hypocalcemia
