SA oestrus cycle + sterilisation

Question 1

When do bitches start their oestrus cycle? How long is an oestrus cycle?

Answer 1

6-18months
-oestrus cycle = 6 months
-mono-oestrus

Question 2

What is the stages of the oestrus cycle? What is the ‘in-heat’ stage?

Answer 2

*Proestrus
*Oestrus
*Dioestrus
*Anoestrus

In-heat = proestrus + oestrus (21 days)

Question 3

What are clinical signs of proestrus?

Answer 3

*Serosanguinous vulval discharge
*Vulva swelling
*Males attracted but rejected

Question 4

What are clinical signs of oestrus?

Answer 4

Fertile period
*Reduction in vulva swelling
*Vulva discharge becomes serous/brownish
*Willing to accept male

Question 5

How long does anoestrus + dioestrus last?

Answer 5

*Anoestrus = 3-4months - sexual inactivity
*Dioestrus = 70days - most common time for pyometra

Question 6

What are important hormones of the oestrus cycle?

Answer 6

*Oestrogen
*Luteinizing hormone
*Progesterone

Question 7

What are the in-heat endocrine changes?

Answer 7

*Proestrus = follicle development (FSH + LH), growing of follicle (oestrogen)
-oestrogen conc peak at end of proestrus

*Oestrus = oestrogen peak = LH surge (24-48hrs after) = ovulation (24-48hrs after)
-Immature oocyte matures (48hrs)
-Oocyte fertile for 48-72hrs
-Progesterone rises after LH surge

Question 8

What hormone is dominance during pregnancy / dioestrus?

Answer 8

Progesterone

Question 9

What hormone is seen during anoestrus?

Answer 9

*Barely any activity
*LH + FSH pulses at end of anoestrus (coming into proestrus)

Question 10

What is seen with vaginal cytology with the different stages?

Answer 10

*Proestrus = round parabasal + intermediate cells - contain RBC + neutrophils
*Oestrus = 100% cornification - anuclear + superficial cells
*Dioestrus = drop from 100 ->50% cornified

PISA
Parabasal, Intermediate, Superficial, Anuclear

Question 11

What hormone is used for oestrus detection in dogs?

Answer 11

Progesterone

Question 12

What is seen with vaginoscopy? What must be done prior?

Answer 12

*Must be under GA
*Proestrus = longitudinal folds - oedema of vaginal mucosa
*Oestrus = Crenations - oedema deflates = wrinkles

Question 13

What are the stages of feline oestrus cycle?

Answer 13

*Proestrus = brief and rarely observed
*Oestrus = induction of ovulation by mating
*Interoestrus = if not induced to ovulate (↓ progesterone and oestrus)
*Dioestrus = if induced to ovulate (↑ progesterone)
*Anoestrus = only when daylight is less than 8 hours

Question 14

Cats are induced ovulators what does this mean?

Answer 14

*Must mate to ovulate

Question 15

What are the benefits of neutering female dogs?

Answer 15

• Population control
• Prevention of pyometra
• Reduced risk of mammary tumours
• Diabetes mellitus management
• Increased life expectancy
• Prevent pseudo-pregnancy

Question 16

What are the risks of neutering female dogs?

Answer 16

• Surgery risk
   1.1% have intra-op complications
   6.4% have post-op complications
   Biggest surgical risk-factors: weight + GA time
   GA itself has mild risk (1 in 1000)
• Urinary sphincter mechanic incompetence
• Ovarian Remnant Syndrome
• Transitional Cell Carcinoma
• Osteosarcoma
• Cruciate disease

Question 17

W/hat is urethral sphincter mechanism incompetence? USMI

Answer 17

*Reduction in urethral closure pressure
*increased risk if spayed younger than 3 month old
*Manage with Propalin or Incurin

Question 18

What is ovarian remnant syndrome?

Answer 18

*Functional residual ovarian tissue after spay
*Neoplasia
*Uterine stump pyometra

Question 19

When should you spay small breed dogs?

Answer 19

*Lower risk of USMI = spay before first season = 6mo
*Unless juvenile vaginitis / recessed vulva

Question 20

When should you spay medium breed dog?

Answer 20

*Lower risk of USMI = spay before first season = 6mo
*Unless breed at risk of cruciate disease - delay until plate closure
-or juvenile vaginitis / recessed vulva

Question 21

When would you spay large breed dogs?

Answer 21

*higher risk of USMI = spay after at least one season
*If breed at risk of cruciate disease = delay until growth plate closure

Question 22

What are the benefits of neutering male dogs?

Answer 22

• Population control
• ‘Behavioural’
• Prophylactic and therapeutic effect on
   Benign prostatic hyperplasia
   Chronic prostatitis
   Perineal adenomas
   Perineal hernias
   Testicular neoplasia (especially cryptorchid)
   Orchitis
   Epididymitis
   Increased life expectancy

Question 23

What are the risks of neutering male dogs?

Answer 23

• GA risk
• Surgery risk
   Post-op haematoma
• Prostatic neoplasia
• Transitional cell carcinoma
• Obesity
• Osteosarcoma
• Worsening behaviour

Question 24

When would you castrate male dogs?

Answer 24

*No repro cycle - neutering not dependent on this
*Allow to mature before neutering - allow behavioural development - 2year old
*Always castrate cryptorchid - abdominal testicle = 14x more likely to become neoplastic