Estrous Cycle Flashcards
What is the reproductive or estrous cycle?
Regularly occurring periods during which the female is sexually active and receptive separated by periods in which there is no sexual activity
What controls the estrous cycle?
hormones
What are the stages of the estrous cycle? (4)
- Proestrus
- Estrus
- Diestrus
- Anestrus
What happens during Proestrus? (6)
- Length of 9 days (2-15)
- High estrogen level
- Blood discharge
- Firm/swollen vulva
- Attracts males
- Won’t accept mating
What happens during Estrus? (6)
- Length of 9 days (3-21)
- Luteinizing hormone (LH) surge
- Increasing progesterone
- Decreasing estrogen
- Swollen vulva softens, bitch will stand to be bred
- Ovulation occurs during this time
What happens during Diestrus? (3)
- Length of 2 months
- High progesterone
- Refuses to allow male to mount
What happens during Anestrus? (3)
- Length 2-10 months
- Low progesterone, low estrogen
- No indication of reproductive activity
What is “determining estrus”?
Predicting the time of estrus increases the chance of pregnancy conception
What is done/used to predict estrus?
Vaginal cytology can be used to predict estrus
What changes in response to ovarian hormones?
epithelial cells lining the vagina
What happens to the epithelial cells during Proestrus? (3)
- Parabasal and intermediate cells start to decrease
- increasing numbers of superficial/cornified cells
- Some neutrophils and RBC’s (decrease)
What happens to the epithelial cells during Estrus? (3)
- > 90% superficial epithelial cells
- No neutrophils
- Decreasing # of RBC
What happens to the epithelial cells during Diestrus? (3)
- Increasing # of parabasal and intermediate cells
- Decreasing # of superficial cells
- Some neutrophils
What happens to the epithelial cells during Anestrus? (3)
- Parabasal cells
- intermediate cells
- +/- neutrophils
What does a serum progesterone assay tell you?
Serum progesterone levels rise 2-3 days before ovulation
