Estrous Cycle Flashcards
When do estrous cycles begin in female farm animals?
After puberty
What characterizes the estrous cycle in females?
Recurrent periods of receptivity to males, providing repeated opportunities to become pregnant.
What marks the beginning and end of each estrous cycle?
Each cycle begins with estrus (heat) and ends at the subsequent estrus.
What is the collective term for the hypothalamus, pituitary gland, and ovary in relation to the estrous cycle?
The hypothalamic-pituitary-ovarian axis
What does “polyestrous” mean?
A type of reproductive cycle where females have multiple estrous cycles throughout the year.
What characterizes “seasonally polyestrous” animals?
They have multiple estrous cycles during specific seasons of the year.
What is meant by “monoestrous”?
A reproductive cycle where females have only one estrous cycle per year.
What species are polyestrus?
cow, pig, queen, rodents
What species are seasonal polyestrus SHORT DAY?
ewe, doe, elk, nanny
= fall breeding season
What species are seasonal polyestrus LONG DAY?
mare = spring breeding season
What species are monoestrus?
dog, wolf, fox, bear
What is anestrus?
Period of reproductive quiescence. This long anestrus eriod is responsible for a cyclic profile of three cycles in two years
What is proestrus?
Proestrus begins with the appearance of a blood-tinged vaginal discharge and by vaginal swelling. It ends when the bitch accepts the male for mating. The ovaries contain large follicles at the onset of proestrus. Estradiol gradually increases and peaks slightly before the onset of estrus
What is estrus?
Shortly after peak estradiol, behavioural estrus beings. Both LH and FSH peak in early estrus. Ovulation is completed at about the third day of estrus and fertilization is completed at about the 6th day. P4 increases during the latter part of estrus signifying luteinization
What is diestrus?
Both pregnany and open bitches are considered to be in diestrus. Pregnancy status doesnt alter length of diestrus. P4 peaks at about 15 days then decreases gradually. Bitches that dont get pregnant are often considered to be pseudopregnant
What makes up the follicular phase
Proestrus and estrus
What makes up the luteal phase
Diestrus and metestrus
How long is the anestrus period?
5 months
How long is the proestrus and estrus period?
9 days each