Estrus

Question 1

Reproductive cycle

Answer 1

• regularly occurring periods during which the female is sexually active and receptive separated by periods in which there is no sexual activity
• Under hormonal control

Question 2

Stages of estrous cycle

Answer 2

Proestrus
Estrus
Diestrus
Anestrus

Question 3

Proestrus

Answer 3

Length of 9 days (2-15 days)
High estrogen level
Bloody discharge, firm/swollen vulva, attracts males, won’t accept mating

Question 4

Estrus

Answer 4

Length of 9 days (3-21 days)
Luteinizing hormone surge, increasing progesterone, decreasing estrogen
Swollen vulva softens, bitch will stand to be bred
Ovulation occurs during this time

Question 5

Diestrus

Answer 5

Length of 2 months
High progesterone
Refuses to allow male to mount

Question 6

Anestrus

Answer 6

Length 2-10 months
Low progesterone, low estrogen
No indication of reproductive activity

Question 7

Determining Estrus in the Bitch

Answer 7

• Predicting the time of estrus increases the chance of pregnancy conception
• Vaginal cytology can be used to predict estrus- epithelial cells lining the vagina change in response to ovarian hormones

Question 8

Proestrus on Vaginal cytology

Answer 8

o Parabasal and intermediate cells present in early estrusà slowly replaced by increasing #’s of superficial/cornified cells towards late estrus
o Some neutrophils and RBC’s

Question 9

Estrus on Vaginal cytology

Answer 9

o >90% superficial epithelial cells

o No neutrophils, decreasing # of RBC’s

Question 10

Diestrus on Vaginal cytology

Answer 10

o Increasing # of parabasal and intermediate cells, decreasing # of superficial cells
o Some neutrophils

Question 11

Anestrus on Vaginal cytology

Answer 11

o Fewer cells- parabasal and intermediate cells, +/- neutrophils

Question 12

Serum progesterone assay

Answer 12

o Serum progesterone levels rise 2-3 days before ovulation
 1-1.9 ng/mlà ovulation in 2 days
 2-3.9 ng/mlà ovulation in 1 day
 4-10 ng/mlà ovulation the same day