Canine Breeding Management

What is the estrus cycle in canines?

Non-seasonal monoestrus breeders

When do dogs go into puberty?

6-23 months old but usually 10-14

How long is the interestrus interval?

4-13 months, usually 7

What is the most common cause of infertility in the female dog?

Inappropriately timed breeding

How long is proestrus?

3-17, average of 9

What behavior changes happens during proetrus?

Attraction of male to female, but female will not allow to mate

What physical changes occur during proestrus/

Swollen vulva and vagina

Serosanguinous vulvar discharge from the uterus

Why is vaginoscopy hard in dogs/

Difficult to visualize lumen

What physiological events occur during proestrus?

Follicular development resulting in gradual increase in estrogen concentrations

Rise in estrogen leads to vaginal epithelial hyperplasia

Estrogen peaks 2-3 days before ovulation then rapidly declines during estrus

Proestrus

In early proestrus (low estrogen) what is on cytology?

Parabasal epithelial cells

Intermediate epithelial cells

RBCs and neutrophils

During mid to late proestrus (estrogen increases), what is on cytology?

Superficial cornified epithelial cells

>90% cornified by the end of proestrus

Fewer neutrophils

How long is estrus?

3-21 days, average of 9

What behavior is during estrus?

Attraction of males to females

Allows male to mount and stands

What physical changes occur during estrus?

Vulva is swollen but flaccid

Straw-colored vulvar discharge

What is on vaginoscopy during estrus?

Crenulated vagina

Prominent vaginal lumen

What physiologic events occur during estrus?

Estrogen concentrations fall at the beginning of estrus

Pre-ovulatory rise in progesterone

LH surge >1ng/mL

What is on vaginal cytology during estrus?

>90% cornified superficial epithelial

No neutrophils

± RBCs

What is a crenulated vagina?

Occurs during estrus, and vagina looks flaky while scoping

How long is diestrus?

50-80 days, average of 60

Estrus cytology

What is behavior during diestrus?

No longer receptive to male

What physical changes occur during diestrus?

Vulva no longer swollen or flaccid

No vulvar discharge

What is on vaginoscopy during diestrus?

Pale mucosa

What physiological events occur during diestrus?

Progesterone is elevated throughout due to CL (happens if pregnant or no)

Diestrus ends with decline in progesterone

Why do dogs not need a maternal recognition of pregnancy?

CL will be present producing progesterone no matter what

What is on vaginal cytology in diestrus?

Sharp decline in cornified epithelial cells on D1 of diestrus

Lots of neutrophils, 40-60% parabasal cells

How late are you if you notice a dog went into diestrus?

2-5 days after oocyte maturation

5-7 days after ovulation

8-9 days after LH surge

Diestrus

How long is anestrus?

2-9 months

What is the behavior during anestrus?

Not receptive to male

What physical changes occur in anestrus?

Uterine involution for 70 days if not pregnant or 90 days if postpartum

What are the physiological events of anestrus?

Progesterone decreases just before parturition and gradually after CL regression

Progesterone < 1-2

What is on anestrus vaginal cytology?

Parabasal epithelial cells

No RBCs

± neutrophils

When is the LH peak?

Day 0 of estrous

What causes an LH peak?

Response to decline in estrogen and rise in progesterone

What marks the end of he follicular phase and triggers ovulation?

LH peak

How long do LH levels increase?

24-48 hours

When does progesterone rise in proestrus?

1-2 days prior to LH surge

What are progesterone levels during estrus?

5-8 at ovulation

7-20 during fertile period

What hormone do you track to determine when to breed a bitch?

Progesterone (7-20 during fertile period)

What are progesterone levels during diestrus?

Steadily rise to a peak of 15-80 ng/mL

When do primary oocytes ovulate?

2 days after LH surge

How long does oocyte maturation take?

2 days

What is the lifespan of a mature oocyte?

2-3 days

When does ovulation occur in regards to diestrus?

6 days earlier

When is whelping?

57 days after diestrus onset

What are some causes of unsuccessful mating?

Inappropriate timing

Dominant female

Inexperienced male

Vaginal abnormalities

Pain

What is pseudopregnancy?

Diestrus, or luteal phase physiologically and hormonally cannot be differentiated from pregnancy

What causes pseudopregnancy?

Physiologic decline in progesterone at the end of diestrus

How long does pseudopregnancy last?

4-6 weeks

What are the characteristics of pseudopregnancy?

Mammary development

Lactation
Abdominal enlargement and slight uterine enlargement

Behavior of whelping and mothering

How do you diagnose pseudopregnancy?

C/S

No pups on rads or US

Undectectable serum relaxin

How do you treat pseudopregnancy?

Nothing if mild

Avoid simulation of mammae

Remove objects female has adopted

Megestrol acetate for 8 days 

How do you prevent pseudopregnancy?

Spaying

What are the problems of megestrol acetate tx for pseudopregnancy?

Can relapse after treatment

Can predispose to pyometra or cystic endometrial hyperplasia