Estrous cycle Flashcards
Estrus
Period when female is sexually receptive
Monoestrous
one estrous cycle per year
Polyestrous
Repeated cycles are uniformly distributed
Cattle, swine, rodents
Seasonally polyestrous
Repeated cycles for a portion of the year
Horses, sheep, goats, cats
Diestrus
period of sexual quiescence separating phases of the estrous cycle in polyestrous animals
Anestrus
period when female does not exhibit estrous cycles
What is day 0 of estrous cycle
Day of ovulation
What are the two stages of estrous cycle
follicular
Luteal
What is the follicular phase
follicles are dominant
20% of cycle
Estradiol
What is luteal phase
Period from ovulation until corpus lutea regression
80% of cycle
Progesterone
What are the 4 stages of estrous cycle
Proestrus
Estrus
Metestrus
Diestrus
What happens during proestrus
Transition from progesterone to estrogen
Female attracts male, but no mating
Estrus
Estrogens
SEX
Metestrus
estrogen to progesteone
no more sex
Diestrus
Maximum luteal function
female refuses male
What are the 2 stages of estrous cycle in the mare
Estrus and diestrus
GnRH
Produced in hypothalamus
Release LH and FSH
FSH
Acts on ovary to produce follicles
Estradiol
Released by follicle
Produce estrous behavior
Triggers LH when low P4 (positive feedback)
Inhibin
Released by follicle
Negative feedback, decrease FSH
LH
LH surge induces ovulation
formation of CL
Similarity between llama and cat
Induced ovulators
Progesterone
Secreted by CL
Maintain pregnancy
inhibits LH
Prostaglandin
Released by endometrium and myometrium
Lyses CL
What does an increase of melatonin do to short day breeders
Makes them want the D
increase GnRH
What does an increase of melatonin do to long day breeders
Decreases sexy time
Decrease GnRH
