Bovine Parturition and Dystocia

Question 1

1. What is the dominant hormone during pregnancy? – Produced by?
2. Hormonal control of parturition.

Answer 1

1. Progesterone – CL, and also placenta between days 120-275.
2. Foetus:
   - HT increases Corticotrophin Releasing Factor (CRF).
   - PG increases Adrenocorticotropin (ACTH).
   - Adrenal gland increases cortisol.
   Placenta:
   - Decreased progesterone.
   - Increased oestrogen (stim oxytocin receptors).
   - Prostaglandin (uterus).
   Mother:
   - Relaxin from ovary softens cervix.
   - Increased gap junctions in myometrial cells.
   - Increased myometrial contractions.
   - Increased pressure on cervix and vagina.
   - Increased oxytocin from PG.
   - Abdominal contractions (Ferguson’s reflex).

Question 2

Signs of impending calving.

Answer 2

Increased udder development.
Oedema of udder and ventral abdominal wall.
Relaxation of pelvic ligaments.
Sinking of sacrosciatic area.
Relaxation of perineum and vulva.
Liquifaction of mucous cervical seal which appears as a cloudy mucoid vulval discharge.

Question 3

1. Average duration of first stage of parturition.
2. Signs of first stage.

Answer 3

1. 6hrs. (range 1-24hrs).
2. Restlessness.
   Inappetence.
   Desire for isolation.
   Tail twitching.
   “Paddling” of feet.

Question 4

1. Average duration of second stage.
2. What happens in second stage?

Answer 4

1. 70 mins (range 30mins-4hrs).
2. Allantochorion ‘water-bag’ ruptutes w/ escape of watery allantoic fluid.

Question 5

1. Average duration of third stage.
2. What happens in third stage?

Answer 5

1. 6hrs.
2. Normal detachment of placenta as a result of:
   - Uterine contractions.
   - Ripening and maturation of placenta.
   - Rupture of umbilicus w/ rapid ‘bleed out’ of foetal side of placenta w/ shrinkage of foetal placental villi.
   - Distortion of the caruncle by myometrial contractions causing detachment of the cotyledon.
   - Gravity.

Question 6

Hormones used for premature induction of calving.

Answer 6

• Water-soluble, short-acting corticosteroid.
• Medium-acting corticosteroid.
• PGF2a or analogues.
• Combinations of medium-acting corticosteroid and prostaglandin.

Question 7

Indications for induction.

Answer 7

• Misalliance.
• Reduce possibility of dystocia – due to foeto-maternal disproportion due to:
  – prolonged gestation.
  – Maternal immaturity.
  – Conformation of the calf.
• Tighten seasonal calving pattern (ethics?)
• Advance time of calving in a cow suffering from disease or injury.
• Excessive oedema.
• Hydrallantois.
• Mummified foetus.

Question 8

Requirements for induction.

Answer 8

• Known service date.
• At least 260 days gestation for the birth of viable calves.
• Full discussion w/ farmer so poss. consequences of premature induction are known e.g. retained placenta.
• Good accommodation and stock person.

Question 9

When to induce.

Answer 9

• Before 100 days of gestation (early abortion): PGF2a.
• 250-275 days of gestation (near term calving):
  – medium acting corticosteroid.
  – medium acting plus short acting corticosteroid.
• Greater than 275 days of gestation:
  – medium plus short-acting corticosteroid.
  – medium acting corticosteroid plus PGF2a.
• After 282 days gestation:
  – medium acting corticosteroid.
  – short acting corticosteroid.
  – PGF2a.

Question 10

Problems w/ induction.

Answer 10

• Sufficient softening and relaxation of the vulva, perinium and pelvic ligaments does not always occur following use of prostaglandins. Better results have been obtained w/ corticosteroids.
• Placental retention is common.
• Uterine involution may ne delayed w/ risk of metritis and chronic endometritis.

Question 11

What are the uses of clenbuterol (Planipart) in bovine parturition?

Answer 11

• Relax uterus in cattle at parturition.
• Delay delivery to allow full prep of soft birth canal in heifers.
• Relax uterus as aid to obstetrical manoeuvres in dystocia i.e. malpresentation and malposture.
• Relax uterus for c section.
• Ensure less traumatic manipulation of uterus in embryo transfer technique.
• Delay and therefore programme delivery to permit observation of parturition e.g. avoidance of night time delivery (uncommon in UK).

Question 12

Signs of dystocia.

Answer 12

• Identifying the exact point at point at which normal birth ceases and dystocia occurs is not easy.
• Overall duration of calving varies considerably but there should be evidence of continuous progress during foetal delivery.
• Birth may be slower in certain breeds such as the Charolais or if the calf is relatively large.
• Calf can survive up to 8hrs during second stage labour but delivery time normally much shorter than this.
• Any apparent or suspected departure from normal should be investigated.

Question 13

Specific signs of dystocia.

Answer 13

• Prolonged non-progressive first stage labour.
• Cow standing in abnormal posture during first stage labour – if uterine torsion, cow may stand w/ dipped back in ‘sawhorse’ posture.
• Straining vigorously for 30 mins w/o appearance of calf.
• Failure of calf to be delivered within 2hrs of amnion appearing at vulva.

Question 14

1. Malpresentation, malposture and malposition examples.
2. What is suggestive of foetal anoxia present or foetal death?

Answer 14

1. • Foetal head, no forelimbs.
     - Foetal tail, no hindlimbs.
     - Foetal head, one forelimb.
2. Detached chorioallantois, foetal meconium or blood stained amniotic fluid at the vulva.

Question 15

1. Presentation of the foetus.
2. Position of the foetus.
3. Posture of the foetus.

Answer 15

1. Relationship between long axis of foetus and maternal birth canal.
   - longitudinal (anterior or posterior).
   - transverse.
2. Which surface of maternal birth canal foetal vertebral column apposes.
   - dorsal.
   - ventral.
   - lateral.
3. Disposition of foetal appendages, legs and head.

Question 16

Main maternal cases of calving difficulty.

Answer 16

• Uterine inertia.
• Ca/Mg deficiency.
• Fatty deposits.
• Environmental disturbance.
• Abdominal pain.
• Inadequate pelvis.
• Breed.
• Immaturity.
• Diet.
• Repro tract.
• Failure of cervix to dilate.
• Torsion.
• Rupture.

Question 17

Main foetal causes of calving difficulty.

Answer 17

Oversize due to:
- Absolute.
- Sire breed.
- Prolonged gestation.
- Development defects.
- Relative to mother.
Faulty disposition due to:
- Presentation.
- Position.
- Posture.

Question 18

Causes of dystocia with the highest incidence?

Answer 18

Foetopelvic disproportion.
Foetal disposition.
Failure for cervix/vagina to dilate.
Other maternal abnormalities.
Other foetal abnormalities.
Uterine inertia.

Question 19

General principles for dealing with dystocia.

Answer 19

• Treat all dystocia cases as emergencies.
• Be prepared for all eventualities w/ protective clothing/instruments/drugs.
  Have a calving kit / caesarean kit in readiness at all times.
• Obtain history either on phone, on arrival or as make preliminary examination.
  – Due date/parity previous calving problems.
  – Sire/recent problems/progress of labour.
  – Interference/vaginal discharge etc.
• Rapid general exam if poss. in case cow suffering from peracute mastitis (may present as uterine inertia) or another life-threatening illness – TPR/Milk Fever etc.
  ALWAYS CHECK UDDER!

Question 20

Restraint when dealing with dystocia.

Answer 20

• Ensure adequate space, light and assistance.
• Cow may be restrained using head collar.
  – Allow her room to lie down.
  – Restrain so quick release is possible.
  – May restrain in a crush for initial vaginal exam but do not attempt to calve a cow in a crush as many go down.
  – A stanchion with a swinging gate is suitable.
• NEVER underestimate risk factor in dealing w/ a calving cow.
• Some become v aggressive, esp. towards strangers.
• Nervous animals may require sedation e.g. xylazine.

Question 21

1. Considerations when examining the vagina.
2. What do you examine the vagina for?

Answer 21

1. • Cleanliness – wash hands and cow’s perineum w/ dilute antiseptic solution.
     - Lubrication!
2. • Evidence of vaginal, cervical, uterine damage.
     - Condition of foetal membranes, discharges, degree of cervical dilation, evidence of obstructions, evidence of foetal life/distress.
     - Position/presentation/posture/size of calf, abnormalities, twins.
     - Tone and condition of uterus, any evidence of torsion.

Question 22

Drugs that can be administered to help repulsion of foetus.

Answer 22

Uterine relaxant – Clenbuterol.
Epidural anaesthesia (5ml 2% Procaine between CV1 and CV2 (not licensed) – may use lignocaine within cascade)) if intense straining preventing repulsion. – eliminates abdo. contractions, no effect on myometrial activity.

Question 23

Bovine epidural injection.

Answer 23

18G 1.5 inch needle (1.1mm x 40mm).
5-6ml.
C1-C2
At 45-60 degree angle.
Into epidural space.

Question 24

Summarised list of drugs to use in parturition.

Answer 24

Local anaesthetic
Xylazine (Rompun)
NSAID
Clenbuterol
Oxytocin
Calcium/Phosphorus
Antibiotic

Question 25

Internal assessment factors relating to the cow.

Answer 25

Is there sufficient dilation of the soft tissues?
Is there sufficient space in the birth canal?
Are there any uterine abnormalities?
Uterine torsion.
Uterine inertia.
Uterine rupture.
Hydroallantois/hydramnion.

Question 26

Internal assessment factors relating to the calf.

Answer 26

• Is foetus too large?
• Is calf positioned correctly?
• Are there anatomical abnormalities?
  – Schistosoma reflexes.
  – Ascites.
  – Siamese twins.
  – Double-headed foetus.
  – Hydrocephalus.
  – Contracted tendons.
• Is calf dead?
• Is there another calf?

Question 27

1. Main aims of a calving.
2. Dystocia with normal disposition.
3. Dystocia with abnormal disposition.
4. If attempted delivery possible?
5. If stifle locks?
6. If attempted delivery impossible?

Answer 27

1. Live cow, live calf, cow able to breed again.
2. Attempt delivery.
3. Correct abnormality and attempt delivery.
4. Either get normal delivery or stifle lock.
5. Calf alive – rotate and deliver.
   Calf dead – rotate and deliver OR foetotomy.
6. Calf alive – C section.
   Calf dead – C section OR foetotomy.
   Calf dead and cow ill – cull cow.

Question 28

When assisting births, remember to…

Answer 28

• Check that head and legs belong to same calf.
• Attach ropes above fetlock.
• Pull when cow strains.
• Ample lubrication, esp. when head being delivered.
• Lay cow on side if delivery difficult.

Question 29

1. What traction to apply to calf to pull calf out?
2. For how long should you apply traction?
3. Successful caesarean depends on…

Answer 29

1. 1 adult at 75kg using 3/4 of their strength.
2. 10 mins then abandon in favour of c section.
3. Early decision.

Question 30

1. When is episiotomy indicated?
2. Solution for hip locked calf.

Answer 30

1. Only if vulva restricting passage of the head.
   Use blade/scissors.
   Preferable to suture after.
   Potential for vaginal wall abscesses.
2. Lubricate and rotate!!!

Question 31

Method of foetotomy.

Answer 31

• Fix body part to saw off w/ chains, ropes, hooks.
• Place wire saw to check piece to take away has right size.
• Make sure saw not including any uterus tissue.
• The operator is responsible to hold the saw in place.

Question 32

What is arthrogryposis – give example, What it can cause, breed predisposition.

Answer 32

Joint abnormalities.
– Fixation of joints, common cause of malpostures, Charolais predisposed.

Question 33

1. What is anasarca.
2. Uterine torsion.

Answer 33

1. Calf dead inside cow and absorbing flid, causing the calf to swell, requiring foetotomy.
2. Where uterus twists on long axis.
   Can be a medical emergency depending on duration. Can cause dehydration and shock. So consider fluid therapy before attempting delivery.

Question 34

1. Breed predispositions for uterine torsion.
2. Associated with?
3. Percentage and direction of rotation?
4. 90 degrees.
5. 180 degrees.
6. 270 degrees.
7. 360 degrees.

Answer 34

1. Brown Swiss and Holstein.
2. Foetal oversize.
3. 75% anticlockwise.
4. Common and easy.
5. Very common and easy.
6. Common but more difficult.
7. Rare and much more difficult.