Reproduction Flashcards
Oxytocin should not be used in which species?
Cattle
Describe the second stage of labour in cattle
Delivery of the calf
Begins with the appearance of the water bag (membranes) at the vulva
May last several hours
Water bag ruptures, cervix dilates with further pressure from calf
Powerful reflex and voluntary contractions of abdominal muscles and diaphragm serve to expel the calf
Describe the third stage of labour in cattle
Expulsion of placenta
Usually happens within a few hours
If not expelled within 12 hours of delivery of the calf, referred to as Retained Foetal Membranes (RFM)
How big should a calving pen be?
12 feet x 12 feet
What properties should a calving pen have?
Size= 12 feet x 12 feet Easy to clean out between calvings A gate, perhaps with a quick release headlock Milking facility Well-bedded and dry Good access to food and water Good lighting Well ventilated and in a quiet area of the farm
When should you intervene during calving?
Only if:
No progress has been made after 1 hour of the water bag showing
Has not progressed to second stage labour after 6 hours (possible twisted uterus)
Cow appears in extreme discomfort
Significant bleeding from vulva
Why should you not intervene too early when the cow is in first stage of labour?
Can prevent full dilation of cervix
Give some causes of bovine dystocia
Foeto-maternal disproportion (heifer impregnated by bull, nutritional, iodine deficiency can lead to longer gestation), dead calf
Malpresentation of calf
Incomplete cervical/vaginal dilation
Uterine inertia (lack of effective contractions; hypocalcaemia)
Uterine torsion (rotation around long axis)
Cervical prolapse
Pelvic fracture
Uterine rupture
Cervical neoplasia
Congenital abnormality (eg spina bifida)
Bull calves more likely to be dystocic
Describe the first stage of labour in cattle
DILATION OF CERVIX
May take 3-6 hrs
Cow separates herself from herd
Appetite decreases
Alternates between lying and standing
Thick string of mucous often seen hanging from vulva
Towards the end, bouts of abdominal straining occur every 2-3 minutes
Abdominal straining pushes uterine contents against the cervix, giving it further stimulation to dilate
How should you approach bovine dystocia?
Restrain
Clean (prevent bacterial entry -> endometritis)
Lubricate
Identify problem
3 R’s: Reposition (calf or uterus), repulsion, rotation
Extract
Which drug can you use to relax the uterus during bovine parturition?
What are some problems?
Clenbuterol
Wont help in delivery-will stop cow contracting
Increases uterine blood perfusion- calf survival?
When might you need to call for back-up during calving?
Caesarean True breech Twisted uterus Lots of bleeding You don't make progress within 20 mins of trying to calve dam
Where should you position ropes/chains when pulling out a calf?
Double loop: one above fetlock (metacarpus/tarsus), one below
Minimal chance of leg fracture or rope slipping off
Use different coloured ropes for different legs so as not to twist them/mix them up
What would tell you that a calf is too big to be delivered per vaginum?
Forelimbs crossing over meaning shoulders are too large to pass through pelvic canal
Head can’t be brought into the pelvis or remain there once traction is released
Not enough room for a hand to be passed between the foetal cranium and maternal sacrum
Unable to exteriorise each fetlock
How would you correct a carpal flexure malpresentation during calving?
Push leg back with one hand, use rope or other hand to pull foot forward
How would you correct a calf with its head back during calving?
Push calf back to give more space, and allow head to fall into correct position between legs
Use head rope to prevent head falling back
Clenbuterol
How can you see if a calf is alive during calving?
Flick tail
Check anal reflex
How do you correct breech presentations during calving?
Repulsion of perineum
Cup the foot over the pelvic brim (take care with hock-pressure on spine)
Regarding cows, are twins more likely to abort if in the same horn or different horns?
Same horn
What is an episiotomy?
When is it used?
Incision in perineum (tissue between vagina and anus)
Calving heifers: if vulva is not fully dilated but cervix is dilated and calf is entering pelvic canal
Try manually stretching vulval lips with arms for 20 mins before resorting to episiotomy
Contamination risk high-give antibiotics
Caudal epidural anaesthesia
Make incision when calf’s head is passing through vulva
Where should you cut when performing an episiotomy?
10-11 o’clock or 1-2 o’clock
Not 12 noon -> recto-vaginal fistula
What are some possible complications of an episiotomy?
Wound infection and breakdown
Distorted vulva conformation (pneumo-vaginum, uro-vaginum)
Weak point to muscles which may affect ability to calve naturally in the future
Rectovaginal fistula if cut at 12 noon
What is required to perform an embryotomy/foetotomy?
Must have sufficient space within vagina and pelvic canal Caudal epidural anaesthesia Clenbuterol Lubrication Good equipment
When would you perform a full embryotomy?
Large dead calf
Foetal monster
When would you perform a partial embryotomy?
Hip locked in pelvis (cut off trunk as close to vulva as possible, split pelvis with wire)
Head back - unable to correct and calf dead (remove head)
Leg back - unable to correct and calf dead (remove leg using ‘passing’ method; must ensure elbow, shoulder and scapula are removed otherwise no narrowing is achieved)
What are the two methods of cutting through a dead calf during calving?
Passing
Cleating
Give some complications of embryotomy/foetotomy
Uterine tears Cervical tears Vaginal tears RFM (retained foetal membranes) Metritis Adhesions
Briefly describe how you’d perform an embryotomy/foetotomy
Remove head using ‘passing’ method of wire placement (cut as far caudal along neck as possible)
Remove forelimb (ensure scapula removed)
Remove thorax using ‘passing’ method (remove as many vertebrae as possible in one cut)
Remove rest of trunk
Split pelvis using ‘passing’ method
Extract one hindlimb at a time
When do most uterine torsions occur during calving?
Onset of parturition
What are the risk factors for uterine torsions?
Poor rumen fill Space in the abdomen Hilly land Process of standing up/lying down Majority are anti-clockwise torsions (whens stood behind cow)
How may a cow appear if she has a uterine torsion?
Appear to start calving but no progression
No straining as Ferguson’s reflex is not stimulated
Slightly raised tail
Dry cow off colour/down/toxic
How can you correct a bovine uterine torsion?
‘Swing’ calf with coordinated ballotment of abdomen whilst holding calf
Twisting the calf’s legs may twist the uterus too
Roll cow (usually from left lateral recumbency -> back -> right lateral recumbency) (grab calf’s leg if you can whilst rolling cow or hold with calving rope or place plank across abdomen during rolling)
Caesarian (if can’t untwist uterus)
Name some complications of uterine torsion
If high degree torsion, the blood supply can be occluded -> friable tissue at torsion site
Dead emphysematous calf and toxic cow
What are the indications for performing a caesarian section on a cow?
Foeto-maternal disproportion
Irreducible uterine torsion
Insufficient cervical dilation
Foetal malpresentation/abnormal calf/dead or emphysematous calf (where foetotomy not feasible)
Constricted vagina and vestibulum (where massage has not relieved constriction)
Why should you avoid sedation when performing a caesarian on a cow?
Can (eg xylazine) cross placental barrier and thus affect calf and decrease viability
Which anaesthesia techniques should be used when doing a bovine epidural?
Caudal epidural (to block Ferguson's reflex) Paravertebral nerve block
What is Ferguson’s reflex?
Reflex comprising the self-sustaining cycle of uterine contractions initiated by pressure at the cervix or vaginal walls
Positive feedback
Which pre-op medication should be given before a bovine caesarian?
Clenbuterol
NSAID
Antibiotic
Calcium where appropriate
Where would you incise when performing a left flank bovine caesarian?
1 hands breadth below transverse processes to 1 hands breadth behind last rib (approximately the length from fingertip to elbow)
Briefly describe a left flank bovine caesarian
Make vertical incision
Locate uterine horn containing calf and exteriorise
Incise uterus (from hock to toe/carpus to toe if breech)
Remove calf
Suture uterus- 2 layers (inverted suture pattern, bury knots)
Clean off contamination from uterus, rumen, remove blood clots from abdomen
Suture body wall and skin (add antibiotics to muscle layers) (‘tack’ layers together to eliminate dead space)
Post-op medication: oxytocin, calcium if appropriate
Which method can you use to cast a cow?
Reuff’s method (uses ropes to bring a cow down to one side)
What is an emphysematous calf?
Dead calf filled with air as they are decomposing
Which sedation would you give to a cow when removing an emphysemetous calf?
Xylazine with ketamine
Where would you incise when performing a caesarian to remove an emphysematous calf?
Between left stifle and point of entry of the milk vein into the abdomen (40-50cm long)
What are some complications of a bovine caesarian?
Haemorrhage (cow may be off colour, tachycardic; re-open and ligate bleed)
Peritonitis (cow may be pyrexic; re-open, identify any leakage, flush abdomen with sterile saline)
Localised adhesions (ovarian, uterine)
Retained foetal membranes
Metritis
Wound infection/seroma/breakdown/emphysema
Why may a cow have a uterine prolapse?
Hypocalcaemia
What causes milk fever in cows?
Hypocalcaemia
How do you replace a uterine prolapse in a cow?
Cow should be standing or in sternal recumbency with HLs out behind her
- Caudal epidural anaesthesia +/- clenbuterol
- Put protective cover under uterus
- Remove foetal membranes and clean off contamination
- Apply lubricant and gradually feed uterus back in (don’t use fingertips -> rupture uterus)
- Once replaced, ensure horn tips fully everted by using a bottle to extend the reach of your arm, or fill uterus with water
- Give oxytocin, NSAIDs, antibiotics, calcium
When during a cow’s life does she start to make profit?
3rd pregnancy