Small Animal repro Flashcards
Explain anatomy of the canine/feline reproductive tract
- Vagina Body: Made of longitudinal folds which increase under oestrus due rising E2 levels → can be used as a guide to stage the oestrus cycle
- Male Dog:
Testes: Orientated horizontally, epididymis is dorsal
Penis: Os penis
Accessory Glands: Large prostate that is palpable via rectum - Male Cat:
Testes: Orientated horizontally/diagonally, epididymis is cranio-ventral
Describe the canine oestrus cycle
Type: mono-oestrus 1-3 cycles/year. except Basenjis, wolves, Tibetan mastiffs cycle once a year.
Cycle duration: 7 months (range 4-12)
Ovulation: Lasts 3 days 2d post LH
Puberty: 7-12 month (6-24 month)
Fertilisation: 48-72 hours
Fertility: Decreases from 4 years, lowered sig. beyond age of 8
Gestation: 57+-1d post D1 OR 65+-2d post LH OR 58-72d from a single mating
What the phases of oestrus in canines?
- Pro-Oestrus: 5-9d (2-25d), Bitch has swollen vulva & blood, E2 ↑ and peaks prior to oestrus
- Oestrus: 6-12d (2-21d): Bitch allows mating, E2 decreases and P4 increases towards the end
- Dioestrus: P4 is the dominant hormone, last in pregnant 57d from D1, non-pregnant 2-3m
- Anoestrus: P4 levels are low causes reproductive quiescence, (resting) lasts 4m (3-10m)
What are the effects of hormones in the oestrus cycle?
- Oestrogen:
o Oedema of the vulva & vaginal mucosal folds
o Thickening vaginal epithelium
o Bleeding from endometrium o ↑ P4 receptors on the uterus
o Development of endometrial glands & mammary ducts
o Attracts males - Progesterone:
o Stimulate further endometrial gland development & secretion
o Suppress contractility of uterus
o Closes cervix
o Suppress leukocyte response in uterus
o Get mated & keep pregnant
What are some unique features of the oestrus cycle?
- P4 ↑ before oestrus
- Standing heat via ↓ E2 & ↑ P4 (increasing oestrogen and decreasing progesterone).
Progesterone levels start to increase BEFORE ovulation. - Ovulation of primary oocytes: Not fertilisable immediately, must undergo meiosis (48-72hrs), to ber eady for fertilisation
How to monitor the oestrus cycle?
- Vulvar turgidity/consistency
Pro-oestrus: Turgid
LH Surge: Sudden drop in turgidity
Oestrus: Doughy
*Vaginal cytology tells you that the bitch is in oestrus, and marks the day that she enters dioestrus
*Vaginoscopy helps to decide when to breed the bitch during oestrus (shrunken angular, pale, dry phase - late oestrus)
- Vaginoscopy/Speculum:
Method: NO lube (sperm toxic), gentle twisting motions whilst avoiding the clit & urethra
1. Pro-Oestrus: Swollen, pink, moist vagina folds
2. Late Pro-Oestrus to Early Oestrus: ‘Shrinking Rounded’ Folds large but shrinking, becoming drier & paler, 2nd transverse folds appear
3. Early Oestrus: ‘Shrinking-Rounded’ Folds large but shrinking as oedema decreases due to E2↓, becoming pale/dry, primary & secondary folds still round
4. Mid-Oestrus: ‘Shrunken Angular’ Oedema almost completely gone, folds are small & becoming angular, is pale-pink/pale & dry
5. Late-Oestrus: ‘Shrunken angular’ Small angular folds, pale & dry
6. Very Late Oestrus: Folds are sharply angular but some crests are becoming rounded & pale with increasing pinkness via epithelial sloughing, malodourous cell-rich opaque discharge
7. Early Dioestrus: Folds are small, pink, moist and round, foul smelling brown discharge (+- White/bloody) for 2-5d, bitch may still be attractive for a few days
8. Dioestrus: Folds are small, round, pink, moist and ‘rosette-shaped’
9. Anoestrus: Same as Dioestrus - Vaginal Cytology:
Method: Moisten sterile cotton bud with saline inserted dorsally in the vestibule to access the cranial vagina through a speculum → twirl 360→ roll on a microscope slide & stain with diff-quik
Superficial Cell Index (SCl): Proportion (%) of superficial cells present on a smear
–> Oestrogen increases the number of layers of cells within the epithelium. Increases distance between most superficial layers and blood supply.
–> Can see which stage of the oestrus cycle
Cell Types:
Superficial Cells: Dead, dark-staining cells with a large angular cytoplasm & either no/pyknotic nucleus (Not vesicular cf. alive cells)
Intermediate Cells: Alive, vesicular living nucleus with clear outline, partly angular (Small) or angular (Large) cytoplasm
Parabasal Cells: Alive larger living nucleus, similar to intermediates but smaller & rounder
Basal Cells: Alive, largest vesicular nucleus, smaller & darker than parabasal cells
Phases:
Dioestrus & Anoestrus: SCI- Low <20%, RBC – No,
Neutrophils - +/- (Most in dioestrus), Debris - +++,
Bacteria - +++,
Thin layer of cells on slide
Pro-Oestrus: SCI – Rising 60-80%+,
RBC – Many sometimes but ↓ progressively,
Neutrophils – Some but progressively ↓, Debris – progressively ↓,
thin layer of cells on slide
Oestrus: SCI – 100% (All superficial), Debris – No (Clear),
RBC - +/-,
Neutrophils – NONE (Otherwise indicates infx/endometritis),
Cell layer progressively thickens with superficial cell rafts (Sheets of superficial cells) in the last 1-2d
(D1) First Day of Cytological Dioestrus: The first day where SCl drops by >20% with an ↑ of >10% intermediates/parabasal cells.
Marks the end of the fertile period
–> Stop further inseminations
- Behaviour Sx:
Tickle/rub the perirenal area between the anus and vulva
Reflexes (Tickle/Rub Perineal Region):
o Vulva reflex: Vulva lifts upwards
o Tail reflex: Deflects to one side
o Lordosis: Less useful, sometimes slight back arching - Hormonal Assays
1. LH: Snap test, not quantitative. Requires, 1-2 times daily, blood sampling to catch LH surge
2. Progesterone: Test every second day. LH surge coincides with a rise in progesterone above 6 nmol/L. Ovulation occurs around 16 nmol/L.
P4 rise above 30 nmol/L = confirms ovulation
*Aim to breed 4-7 day after LH surge using identified P4 (or LH)
*P4 value cannot indicate when it is too late to breed/D1
–> Only vaginal cytology can tell
Describe the Feline Oestrus Cycle
- Type: Seasonal polyoestrous (Summer) induced ovulation +- spontaneous, esp. in Orientals
- Puberty: 4-12m age
- Ovulation: 29-40hrs post coitus
- Oestrus: 7d
- Gestation: 66d (64-69d)
Phases
- Non-mating: E2 follicular phase for 1wk & interoestrus for 2wks (Low E2)
- Ovulation w/o Conception: LH surge in follicular phase → dioestrus (4-5wks) → ovarian inactivity (2wks)
Dx of Pregnancy
Diagnosis of pregnancy
- Abdominal Palpation: 15-30d
- US: >16d
- Radiographs: >40d
- Nipples Pinking: 2-4wks
How to approach breeding management?
- Ask owners to bring in bitch a few days after noticing vaginal bleeding
- Perform basic oestrus monitoring (OM), e.g, Reflexes, turgidity, vaginoscope, cytology
- Repeat OM every 2-4d initially; preferably 2d once LH surge until breeding/D1
- Add P4 (+-LH) as required
How to manage fresh semen via AI or natural breeding?
Fresh semen AI or natural breeding:
- Breed when enter the pale-dry-shrunken angular (100% SCI) phase, usually 4 days after LH surge
–> Oocytes 4-5 day prep for fertilisation + 2d ovulaion post LH = 4-5 window before D1 - 2-3 inseminations/matings done every second day, during the most fertile period (last 4 days of oestrus)
- Lifespan: 1 week
- Dose: > 150 million
Method for Fresh Semen AI:
- Check semen motility beforehand → carefully draw into warm pipette & syringe
- Insert pipette dorsally into vulva avoiding the clit/urethra to the fornix, as deep as possible
- Lift the bitches back legs and expel the semen → massage clit for 30s to encourage oxytocin
- Keep hindquarters elevated or 10m unless using TCI or Mavic catheter
What is a Mavic AI Catheter?
- Mimics the bulbus glandis of the dog penis
- Balloon is inflated following placement of catheter into vagina
- Sperm is passed through the catheter, followed by post-sperm fraction/semen extender. Injected slowly over 10 minutes
How to manage fresh chilled semen/frozen semen?
Fresh chilled Semen
Timing: 4-5d post LH surge
Frozen Semen
Lifespan: 24hrs once inseminated Timing: 5.5d post LH surge
Dose: Small dose 100 mil
Method:
- Using either a Norwegian pipette, surgical or using an endoscope to catheterise cervix (TCI)
- Inseminate directly into uterus instead of cranial vagina
What are important hormones in pregnancy?
- Progesterone – not specific for pregnancy
- Prolactin – increases throughout dioestrus, not specific
–? luteotrophe (maintains the CLs)
–> preparing for, and maintaining, lactation - Oestrogen – small rise during second half of gestation
- Relaxin – pregnancy specific – detectable from D21, rises through second half of gestation
Diagnosis:
- Abdominal palpation
- Radiography
- Ultrasound
- Hormone assays: Relaxin
How do you estimate gestation length?
Indications:
- When dealing with dystocia
- Managing a C-section or pregnancy termination
Whelping:
- 58 to 72 says from a single mating
- 63-67 days after the LH peak
- 56-58 days post D1
- Long fertile period due to longevity of sperm in the reproductive tract (7 days of fresh semen)
- ALSO 4 day fertilisation period at the end of oestrus
*11 days prior to D1 during which mating result in pregnancy
–> Range of when birth will be due to this
Estimating Gestation date:
- Number of days from mating to today
- Gestation length range from D1
- Further mating dates: Widens the window
Also use progesterone levels to predict:
- If p4 lower than 8.7 nmol/L: 48 hours
- If P4 < 3.18 nmol/L: 24 hours
- If P4 low, likely to be close to whelping
- If P4 high, unlikely to whelp within 12 hours
Other methods:
- Ultrasound measurements of amniotic sac, embryo/foetus
- Radiography
- Auscultation of foetal heartbeats: last 5 days gestation
- Relaxation of abdomen, preineal area and paracervical area
–> Abdomen changes from barrel shape to pear shape
–> Cervix becomes visible when paracervical area relaxes
- Mucoid discharge: Liquifaction of mucous plus: 4 weeks to 1 day prior to whelping
- Lactation: 2 weeks prior to whelping
- Rectal temperature may fall one degree witihin 24 hours to 36 hours of parturition. Not reliable
What are the stages of parturition?
- Stage I: onset of uterine contractions, relaxation of the cervix, ~ 6 – 12 hrs
- Stage II: full dilation of cervix to expulsion of final foetus (hrs)
- Stage III: expulsion of foetal membranes (usually follows each pup)
What is Dystocia?
- Maternal vs foetal causes
- Primary inertia: Failure to push
- Obstructive dystocia: Pushing is futile
Signs:
- Strong tenesmus (painful defecation) for 20-30 min without pup
- Weak intermittent tenesmus for more than 2-3 hours
- More than 4 hours between pups
- Green discharge before the birth of first pup
–> Placental separation: Oxygen supply may be compromised
- Abdominal discharges e.g. black, bloody, purulent, stinking
How to diagnose Dystocia
Abdominal radiographs:
- Number of foetuses present/left
- Gestation length
Ab US:
- Normal foetal heart rate: >220 beats per minute
- HR < 180 bpm: Getting nervous
- HR <150 bpm: Proceed to C-Section
Digital palpation
Vaginoscopy
- Identify foetal membranes = cervix dilated
- If dilated: C-section safe
