Repro 4 Flashcards
What is the percentage of abortion diagnosis that find a cause and list the 2 main causes of abortion in sheep
50% will not find out the cause Abortion 1) Campylobacter foetus spp foetus ○ Both Campylobacter foetus subsp foetus and Campylobacter jejuni cause abortions 2) Toxoplasma gondii
Campylobacter feotus spp foetus what type of organism, what age are the abortions, clinical signs, abortion rates and re-infection rates
- Commensal organism of the in the gastrointestinal tract -> ingestion generally from carrier sheep
- Result in late-term or full term abortions
- Often no signs that ewe is about to abort
- Can develop metritis following abortion but death is uncommon in the ewe
- Abortion rates after infection is about 10-20%
- A ewe that has aborted will develop immunity to re-infection
Campylobacter feotus spp foetus what are the short and long term management strategies
Management in the short term
- Removal of aborted ewes to another paddock
○ Need to be careful about moving and stressing the heavily pregnant sheep, as well as exposing more sheep and pasture contamination
- Husbandry, social grouping, stocking rates -> stress etc.
- As commensal organism so can’t just give antibiotics
Management in the long term
Vaccinate -> cooper guardian campylobacter vaccine
What is the progesterone block and when needs to be removed
support gestation, immune response lowered, contraction low -> need to remove for parturition
What are the 10 steps in the partition process
- Foetus grows too big for uterus, not enough nutrients -> hypoxia -> foetal stress
- Release of adrenal corticotropin hormone (ACTH) from foetal anterior pituitary
- Corticosteroid level rise (from foetal adrenal cortex)
- 1multiple similar enzymes are activated by high corticosteroids levels
- Progesterone (progestagens) are converted to Oestradiol - IMPORTANT STEP
ALSO foetal corticosteroids cause the placenta to synthesize PGF2alpha -> luteolysis - Dramatic decrease of progesterone and increase in oestradiol
- Removal of the progesterone block + high oestradiol + PGF2alpha levels -> increased myometrial contractility
- Increase myometrial contractions push the foetus closer to the cervix
- Cervical stimulation results in increased oxytocin production via Ferguson’s reflex
- Increase PGF2alpha leads to an increase in relaxin production from the CL and/or placenta
- Relaxin relaxes the pelvic ligaments and loosens the other tissues at the birth canal by softening the connective tissue, also in the cervix
ALSO have voluntary abdominal contraction to remove the foetus
What hormone results in the lubricates the birth canal
Oestradiol -> increase secretion from glands in reproductive tract particularly the cervix
What are the 4 steps in the Ferguson’s reflex
- Pressure on cervix (from myometrial contractions so foetus pushed closer to cervix)
- Trigger via paraventricular nucleus in the hypothalamus -> release of oxytocin
- Oxytocin into blood stream
- Leads to strong uterine contraction
How many days after the LH surge does whelping occur and what occurs with single puppies
LH surge (day zero) from this point takes 65 +/- 1 day
- Single puppies -> often born of end up in a dystocia
○ Single puppy cannot produce sufficient ACTH
○ Need to do a C-section to remove however can be hard to determine when ready to be delivered
§ If test the heart rate via ultrasound and start to decrease when stressed -> should be about 240-220
What are the 2 main things you can test for to see whether whelping is about to occur
1) Take rectal temperature twice per day
§ Temperature drops 8-24 hours prepartum due to loss in progesterone
2) Optional: serum progesterone assess daily in last few days
§ Progesterone drops 24-48 hours perpartum
What are the 2 main reasons for induction of parturition and what within
- As a management tool
a. Synchronise calving in dairy herds
b. Embryo transfer calf
c. Batch farrowing in sows
d. Facilitate cross mothering in sows
e. Concentrate labour efforts
f. Observe parturition - For medical reasons “high risk pregnancy”
a. Undesirable pregnancy of heifer -> not sufficient weight when mating to carry the calf
b. Ruptured prepubic tendon
c. Excessive udder oedema
d. Maternal disease-> HypoCa, Preg Tox, Hydrops…
f. Prolonged gestation in cows
g. Neonatal Isoerythrolysis (NI) foals
Compare abortions in early pregnancy vs those in mid gestation
Abortion (Early Pregnancy)
- Few complications
○ Early Embryonic Loss (EEL) is a ‘natural’ process
Abortion (Mid gestation)
- Complications -> hardest time due to progesterone block
○ Failure of abortion
○ Require multiple treatments
○ Risk of dystocia
○ Increased risks of
§ RFM, Metritis, Delayed uterine involution
List 7 indications for abortion
- Misalliance
- Female too young
- Wrong sire
- Bred out of season- Female entering feedlot
- Reproductive pathology
- Fractured pelvis
- Ruptured prepubic tendon
- Excessive udder oedema
- Mare with twins
What is the main thing that maintains pregnancy and list the 4 ways to reduce the activity (induce)
PROGESTERONE
1) Stopping production (eg Luteolysis)
2) Using it up (eg cortisol increases metabolism -> turn into oestrogens)
3) Blocking it (eg agonists block receptors)
4) Over-riding it (eg applying Oxytocin directly)
What are the 2 main options as drugs that induce abortion or birth and how work
1) Corticosteroids
1. activate the enzyme that metabolise progesterone
2. cortisol metabolised cholesterol into oestradiol (less metabolised into progesterone)
2) Prostaglandin PGF2alpha -> results in luteolysis - decrease in progesterone production, also increase in myometrial contractions and release of relaxin that relaxes smooth muscle around the birth canal
What are the 3 corticosteroids used in cattle how long is the effect
- Dexason/Dexapent – Dexamethasone sodium phosphate
- 30 x more anti-inflammatory effect than cortisone
- Acts for about 48 hours - Trimdexil – Dexamethasone trimethylacetate
- Medium acting
- Calving induction, ketosis - Dexafort
- Combination sodium phosphate (rapid onset) and Phenylpropionate (long acting)
- Short and long acting
- About 10 days
What are the 2 main drug formulations used in cow abortions, when used, how long take to abort and possible risks
- PGF2alpha
○ 5 days after end of oestrus (comes into oestrus in 3
○ 5 days, but takes up to 10 days to abort)
○ ~100% reliable during first 3-4 months
§ To preg test or not to preg test?
○ Unreliable between 5 – 8 months gestation - PGF2alpha plus short acting corticosteroids
○ Effective between 5 – 9 months
○ Animals abort in about 5 days
○ Risk of RFMs, dystocia and metritis
Calving induction what used for, how early can it be done, how long does it take, what is occurring in the industry and vets role
- An aid to management in seasonal calving herds
- Can induce cows to calve up to 4 months early
- But we want them to lactate
- Takes days-weeks
- Practice is being phased out (except for therapeutic reasons)
- In 2016, vets needed special permission to induce >15% of a herd
What are the 2 main drugs used for calving induction and how long until calve after injection
Use corticosteroids
1) Short acting dexamethasone
○ Within 10 days of term, 90% calve in 45 hours +/- 5 hrs
○ PG: Calve in 1 – 4 days
2) Long acting dexamethasone
○ 25 – 30 mg Dexamethasone Trimethylacetate (Trimedexil)
○ In 2 weeks-time
§ If udder development ready to calve, give PG
§ Otherwise repeat Dex
§ Calve more quickly as pregnancy progresses
What are the 5 main downsides of calving induction
- 5% decreased milk production
- High incidence of RFM -> not as bad if come back 14 days later
- Significant incidence of toxic metritis
- High calf mortality
a. stillbirths or non-viable - Reproductive performance unaltered
Ewe abortions what are the 2 drugs used and what stage of gestation and what drug is used for ewe induction with time in which they would lamb
Ewe Abortion 1. PGF2alpha ○ Effective during the first 50 days of gestation 2. Corticosteroids ○ Not highly effective until late gestation Ewe Induction - Short acting corticosteroids ○ 70 – 90% lamb in 1 – 3 days ○ Efficiency declines before day 140
Doe abortion what drug used at what stage of pregnancy
- PGF2alpha
○ Single dose effective throughout pregnancy at inducing abortion and parturition
What are the 3 options for mare abortions, what needs to be done based on gestation length, which method of choice and possible side effects
1) PGF2alpha
○ Method of choice
○ Single injection up to day 35
○ Multiple injections up to 5 days after day 35
○ Don’t react well -> sweat, colic
2) Cervical dilation and intrauterine infusion of saline, tetracycline, dilute iodine
○ Significant risk of dystocia after 7 months
3) Manual dilation of cervix with or without oxytocin and removal of foetus not recommended after 7 months
List 7 reasons for mare inductions and what must it involve
Must have severe (life threatening) risk to mare or foal 1. • Fractured pelvis 2 • Previous NI foals 3. • Ruptured prepubic tendon 4. • Repeated stillborn foals 5. • EHVI in foaling unit 6. • Not udder oedema!! 7. • Not prolonged gestation
Mare inductions after what day of gestation and the 2 main drugs used and when foal delivered after injection
> 330 days of gestation
1) Oxytocin -> common
- Oxytocin 5 IU iv and 40 IU im
○ Wait 20 minutes and repeat
○ Foal normally delivered within 1 hr
○ Be in attendance with dystocia equipment
2) Prostaglandins -> not as common
- Lutalyse (dinoprost)
○ Time of onset is variable and is associated with foal deaths -> variable
- Estrumate (fluprostenol)
○ Safer but onset is still variable from 30 min to 3 hrs
What are the 4 main downsides of mare inductions
- Premature placental separation
- Maladjusted foals common
- Fractured ribs common
- Dystocias common
Sow abortion what drug used at what stage of gestation and sow induction what drug used, off-label in what species and downsides
Abortion - PGF2alpha ○ Single dose effective throughout pregnancy at inducing abortion and parturition Induction Blocking Progesterone receptors - Aglepristone (Alizin®) ○ Off label in other species (cat, rat, rabbit) (on label for 0-45 days in bitch) downsides -> expensive and MUST BE GIVEN BY A VET
Bitch abortion what is the main drug and what occurs with different gestation lengths, how many injections and induction of parturition in btich
- Aglepristone (Alizin®) is registered in Australia for induction of abortion in the bitch from 0 – 45 days after mating
○ Before about 35 days, foetus is resorbed
§ Should wait till off heat as if given then mate again 2-3 days later
○ After 35 days, they deliver the foetus -> not nice, want it to be done before this
○ 2 injections 24 hours apart
○ MUST be given by a vet
Bitch – induction of parturition - Off-label use of Alizin
- Evidence it’s safe from day 58-59
- Takes >24h
- Pregnancy can always be terminated surgically in the dog and cat!
abortion in the queen what are the two main methods
1) Alizin is off-label but reported to work up to day 45
2) Desexing a better option in most cases!
Define a mammary gland, nipple/teat and udder
Mammary Gland
- A mammary gland is an organ in mammals that produces milk to feed young offspring. It is an exocrine gland that is an enlarged and modified cutaneous sweat gland, and gives mammals their name.
Nipple / Teat
- Projection of a mammary gland through which milk flows
Udder
- Another word for mammary glands – especially those that are big and baggy
Describe the embryology of the mammary gland
- Derives from Ectoderm and Mesoderm ○ Derived from skin - Mammary Buds - Mammary Ridges 1. mammary buds form from mammary ridges 2. Epidermal sprouts give rise to ducts and alveoli ○ One sprout ‐1 duct system ○ Multiple sprouts ‐multiple duct system
What is the teat sphincter and alvoeli
Teat sphincter -> prevent milk from being exposed to air and therefore bacteria (perfect medium for growth)
Alveoli -> milk producing units
- Cuboidal epithelial cells, myoepithelial cells - Eject the milk from the udder , capillaries
What are the 2 main supporting structures of the mammary gland
1) Lateral Suspensory Ligament
2) Median Suspensory Ligament - through midline of the udder from the pelvis
- Has 2 layers
○ Complete separation of right to left
○ Incomplete separation of front to back
- Rupture of suspensory ligament results in teats moving outwards and dropping of udder
Blood supply of the mammary gland, how many liters needed to make a liter of milk and the arterial and venous supply
○ 500 litres of blood to make a litre of milk Arterial: - External Pudendal ○ Inguinal canal ○ 1.5‐2cm diameter ○ Sigmoid flexure at inguinal canal - Ventral Perineal ○ Pelvic canal ○ Minor contribution Venous - “Milk Vein” ○ (aka Superficial cranial epigastric/abdominal) - External Pudendal vein - (perineal vein) “Venous ring” - Forms during pregnancy - Anastamoses of all veins - Valves become incompetent
What is the lymphatic drainage tract in the mammary gland
- 2‐4 mammary Lymph nodes each side
○ “Superficial Inguinal” or “Mammary” LNs - Then to medial iliac LNs
Innervation of the mammary gland what are the 3 nerves involved and what do they supply
- 1st and 2nd Lumbar nerves ○ Skin cranially - Perineal Nerve ○ Skin caudally - Genitofemoral (inguinal) nerve ○ Internal, deeper tissues
What are the gross anatomy structures from the alveoli to environment in the cow mammary gland
Secretory units(alveoli) ->
Small intralobular ducts (within lobules) ->
Larger interlobular ducts ( in interlobular septa) ->
Lactiferous ducts
Progressive increase in diameter but decrease in numbers ‐ ~ 10 enter ->
Gland sinus (cistern) - sinus = cavity ->
Teat sinus (cistern) ->
Teat canal ->
Exterior
