1. Disorders of oestrous cycle of the bitch - abnormal estrous cycle length

How long can bleeding be considered normal in a bitch?

40 days

What is the possible range of pro-oestrus, oestrus, and dioestrus length in a bitch?

63-142 days

What are examples of abnormal oestrus cycle length?

1. Rapid return to oestrus

2. Shortened inter-oestrus interval

3. Lengthened inter-oestrus interval

4. Lengthened period of proestrus or oestrus

What does a return to oestrus in less than 7 months indicate in a bitch?

Ovulation didn’t happen, and another follicle developed straight after

What are the potential causes of a rapid return to oestrus in a bitch?

Puberty or split oestrus

How can puberty cause a rapid return to oestrus??

During first cycle ovulation can fail. Normal; can take a few times to get ovulation.

What is split oestrus in a bitch?

A short interval between pro-oestrus signs (bleeding)

In which bitches is split oestrus most common?

Pubertal bitches or those under 4 years old

What occurs during split oestrus?

Follicle growth and oestrogen production, but regression of follicles before ovulation

What is the treatment for split oestrus?

Generally no treatment is needed

What are examples of causes of shortened inter-oestrus interval?

1. Ovulation failure

2. Short luteal phase

3. Short anoestrus

What can cause ovulation failure?

Low LH (particularly in older bitches)

How can ovulation failure due to low LH in older bitches be treated?

500 IU hCG every day for 3 days to ensure ovulation at next oestrus

What defines a short luteal phase in a bitch?

Lack of progesterone. Progesterone from the CL returns to normal levels 20-40 days after ovulation instead of 60-65 days

What condition can cause a short luteal phase in bitches?

Loss of pregnancy

Which breed is most commonly affected by a short luteal phase?

German Shepherds

How can a short luteal phase be managed in pregnant bitches?

Supplement P4 during pregnancy

What are the risks of supplementing P4 during pregnancy in bitches?

Cryptorchidism in male puppies and masculinisation of female puppies

What factor can shorten anoestrus in bitches?

Contact with bitches in oestrus (dormitory effect), shortening anoestrus by 30 days or more

What is the average interval between oestrous cycles in bitches?

7 months

How long can the inter-oestrus interval be in some bitches?

Up to 11 months

How does age affect the length of the inter-oestrus interval?

It increases with age

What are examples of causes of lengthened inter-oestrus intervals?

1. Prolonged luteal phase

2. Prolonged anoestrus

How long should the luteal phase last in a normal bitch?

65 days

What can cause a prolonged luteal phase in bitches?

Luteal cysts or progesterone-producing ovarian neoplasms (both rare)

What defines prolonged anoestrus in a bitch?

A lengthened period before the next oestrus cycle occurs

What can cause a lengthened period of proestrus or oestrus?

1. Delayed ovulation

2. Follicular cysts

3. Oestrogen producing ovarian neoplasia

What is delayed ovulation in bitches?

No ovulation within 30 days of pro-oestrus

What is the normal range for ovulation timing in bitches?

5-25 days, average 12 days

What are the possible causes of delayed ovulation?

Inadequate LH secretion or insufficient LH receptors:

What treatment can be given for delayed ovulation?

hCG

What should be suspected if a bitch shows oestrus behaviour for more than 30 days?

Follicular cyst or oestrogen-producing ovarian neoplasm

How can a follicular cyst be diagnosed in a bitch?

Ultrasound (USG); 8-12mm, thin-walled, anechoic structures

How should an oestrogen-producing ovarian neoplasm be treated in a bitch?

Ovariohysterectomy

Which hormone is involved in pseudopregnancy?

Prolactin

Which hormone is used to diagnose a silent heat?

P4