Infertility and obstetrics cattle/ruminants Flashcards
What does superfecundation mean
Offspring born from more than one sire
What does superfetation mean
fetuses developing and born at different stages; doesn’t really happen
What is the biggest cause of no offspring from a mating
Early embryonic death
Fetal mummification
Often no bacterial contamination
Resorption of fetal fluids
Fetal maceration
Fetal death with bacterial contamination so get decay in utero
Emphysematous fetus
When there is death at a late stage of gestation; e.g neglected dystocia
-> Decomposition produces gas which causes emphysema of fetal tissues
Which type of hydrops is more common
Allantois
Treating hydrops uteri in cattle
Depends on value of calf vs cow
- May do elective c section
- May just leave her; but be prepared to assist in parturition due to likely uterine inertia
- Can induce birth; but risk of calf death due to prematurity
- Can drain fluid; but will re-fill + risk of infection
What do we worry about when inducing birth of a calf
Won’t have functioning adrenal glands
How do we induce birth at different stages of cattle gestation
Up to day 100/150: CL is providing progesterone so can use PGF2alpha
From day 150-270: placenta is providing progesterone so need corticosteroids
Risk factors for vaginal and cervical prolapses
Older, multiparous animals: more relaxation of pelvic ligaments
Ruminal distension
Increased intra-abdominal pressure e.g due to straw within rumen
Oestrogens in diet (white clover)
Breed e/g Herefords
Risk of dystocia in bovine parturition
3-10%
Parturition stages in cattle and timings of it
1) Preparatory stage: 2-6 hours
- Calf rotates to an upright position; uterine contractions begin and amnion is expelled
2) Foetal expulsion: 30 mins to 4 hours
-3) Expulsion of fetal membranes: 2-8 hours
Most common causes of dystocia in cattle
Main one = feto-maternal disproportion
Then fetal maldisposition
What does presentation mean in relation to birth position
Relationship between longitudinal axis of fetus and birth canal e.g anterior or posterior
What does position mean in relation to birth position
Which birth canal surface is fetal spine applied to e.g dorsal or ventral
What does posture mean in relation to birth position
Disposition of limbs of the fetus e.g extended or flexed
Which drugs might be given during a dystocia case
Xylazine for sedation
Clenbuterol to reduce myometrial contraction strength (NB: will counteract the increased contractions caused by xylazine)
Denaverine: antispasmodic; promotes dilation of birth canal
When would we NOT use denaverine (anti-spasmodic) in dystocia
With mechanical obstruction of birth canal e.g oversized fetus, uterine torsion, fetal maldisposition
How to distinguish fore and hindlimbs when palpating fetus
Forelimb fetlock and carpus bend in the same direction
Hindlimb joints bend in opposite directions to each other
What additional signs of fetal life can we look at in a posterior presenting calf
Anal reflex, umbilical artery pulse
what do we describe as the maxmum pull that should be applied to a fetus during traction
Well coordinated pull of 4 average people
What is the most common MATERNAL cause of dystocia
Uterine inertia
Due to hypocalcaemia/magnesaemia; overstretching of myometrium e.g in hydrops, fatty infiltration of uterus, hormones
OR may be SECONDARY e.g to exhaustion
In what breed is normal delivery not usually possible due to inadequate size of birth canal
Belgian blue
Why might we see incomplete dilation of cervix in cattle (NB rare)
Most likely hormonal issues; or hypocalcaemia
May relate to fibrosis of the cervix
What is associated with incomplete relaxation of vagina and vulva
Dairy heifers
Over fat body condition
Or interruption during parturition
What direction does uterine torsion more commonly go in
Anticlockwise
Usually 90-180 degrees
When can’t we correct uterine torsion per vaginum
If anterior to vagina
Or >270 degree torsion
What is an episiotomy
Making a cut to increase diameter of vulval opening
Should be done dorso-laterally at 11 or 1 o’clock
Options to deal with feto-maternal disproportion
> Supplementing contractions with traction
Episiotomy to increase vulval opening diameter
C section
Fetotomy to reduce volume
How soon do we want a calf out within traction being applied
10 mins
At what point in posterior delivery must we avoid any delays because calf compromised
Once umbilical cord trapped; i.e after tail head and anus is out
What is ‘true breech’ presentation
Hip flexion; to correct should retropulse then push limb into hock flexion and then straighten this
What is the normal position for birth
Dorso-sacral i.e fetal spine upwards towards maternal pelvis
What does dorso-pubic position mean
Fetal spine is down towards pelvis i.e upside down fetus
What does dorso-iliac position mean
Fetus lying on side
How can we use pressing eyeballs in calves to correct faulty position
Triggers a convulsive reflex
How many cuts does a complete fetotomy usually require
4-6
Difference between a subcut and percutaenous fetotomy
Subcut is within skin; can be used to remove forelimb in anterior presentation; incise skin a little and break down muscle
Percutaneous = making full cuts through body
What is the most common reason for fetotomy
HIp lock
post-fetotomy management of a cow
Uterine flushing
Oxytocin to aid involution
NSAIDs and antibiotics
Fluids
What is prognosis of a c section most related to
Duration dystocia has been left
What is the preferred surgical site for cow c section
Left flank standing laparotomy
What is a complication with giving xylazine for sedation during c section
Increases the intensity of uterine contractions
+ can reach calf and cause sedation; reduces fetal cardiovascular function
What is a side effect of clenbuterol (for myometrial relaxation)
Delays uterine involution
Options for cow c section anaesthesia
Line block; over incision site BUT delays healing
Inverted L block; above and to side of of incision - won;t affect healing
Paravertebral block
Can do epidural
What limb will we palpate during c section depending on presentation
If anterior; will feel hindlimb
If posterior; will feel forelimb
How to repair a uterine incision; abdomen and skin
Continuous layer of inversion sutures for uterus
Continuous sutures for muscle
Non-absorbaby ford-interlocking or horizontal mattress for skin
When might we choose a right flank incision for C section
Lots of previous C sections so much scar tissue
L side not accessible
Fetus in right horn
When might we choose a ventral/midline incision for C section
If calf dead/emphysematous to avoid fluid spilling into the cow
- Must sedate cow and cast in lateral recumbency
MOst common causes of dystocia in EWEs
Most common = fetal maldisposition
Then obstruction of birth canal
MUCH MORE RARE to have it due to disproportion
Considerations when approaching dystocia in the ewe vs cow
Uterus more friable so take care
+ More risk of infection so must be more hygienic
Tissue breaks down easier so easier to do a subcut fetotomy compared with cow
What position do we normally do a c section in a sheep
Lateral recumbency
Treating acidosis in neonatal calves
Inject 50ml of sodium bicarbonate
Incidence/consequences of retained fetal membranes in cows vs sheep
More common in cows
BUT worse consequences in sheep
How common is RFM incidence in cows
8-12%
Risk factors for RFM
NB: management factors involved because separation process starts weeks pre-partum
- Age, dystocia, multiple births, inductino
- infection-related abortion
- Deficiencies in cit A, E, selenium, Ca2+, Cu2+, iodine
- High body condition; fatty liver syndrome
- Hormones; lack of PGF2a, low progesterone, hgih oestradiol
What treatments can help with RFM
Avoid manual removal esp on septicaemic animals
Antibiotics; only if systemically ill + only parenteral
Hormones: PGF2a if low in this; oxytocin if in first 24hours post-partum
Contributing factors to uterine prolapse
Poor uterine tone
Oversized fetus
Prolonged dystosia
Increased intra-abdominal pressure
High oestrogens in diet
Too high BCS
What is the New Zealand method for correcting uterine prolapse
Pull back legs all the way back; then sit between legs and correct
In what breeds do we sometimes see congenital ovarian hypoplasia
Swedish Highlands
White ayrshire