Cyclicity Flashcards
The events that occur between periods of sexual receptivity are called?
Estrous
The actual period of sexual receptivity is?
Estrus
What event is considered day 0 or day 21?
Estrus
What are the 3 types of estrous cycles?
Polyestrous, seasonally polyestrous, and monoestrous
Cattle and swine have this type of estrous
Polyestrous
Which estrous is characterized by clusters diving the year of cycles?
Seasonal polyestrous
Monoestrous means that animals cycle how many times a year?
One
Which hormone indicates sexual receptivity?
E2
What are the 2 main phases of estrous?
Follicular and luteal
Which hormone is in dominance during the follicular phase?
E2
What is happening in the follicular phase?
Sexual receptivity, elevated GnRH, ovulation
What 2 phases make up the follicular phase?
Proestrus and estrus
Proestrus begins with what ?
With luteolysis and a decline in P4
An increase in estradiol and decrease in progesterone means what occurs in proestrus?
A major hormonal shift
What are some behavioral signs of estrus?
Cordons, increased vocalization, increased movement
Which hormone reaches its peak at estrus?
Estradiol
The phase where progesterone is dominant, follicles are growing and the body is preparing the reproductive tract for pregnant or cyclicity?
Luteal phase
Which 2 phases are part of the luteal phase?
Metestrus and diestrus
The period between ovulation and the formation of a functioning cl is called?
Metestrus
What does the corpus luteum secrete?
Progesterone
What does progesterone cause?
A negative feedback to GnRH
What characteristic of hormone levels is special to metestrus?
Both e2 and p4 are low early on
What is the period of maximal luteal function?
Diestrus
Why is progesterone high in diestrus?
Because there is a functioning CL
What does diestrus end with?
Luteolysis
What are some factors that explain anestrous?
Pregnancy, lactation, stress, illness, body condition
The estrous cycles of the bitch has how many phases?
4: anestrus, presorts, estrus, diestrus (no metestrus)
What is happening in anestrus?
FSH is basal, progesterone is low, and LH surges but not enough to engage the surge center
How long is proestrus?
9 days
In estrus, how long does it take the bitch to ovulate after standing heat?
3 days
Fertilization occurs how many days after ovulation?
3 days
Which phase is characterized by a peak in P4 after 15 days and not being affected by pregnancy?
Diestrus
What may happen during diestrus that is more prevalent in canines?
Pseudopregnancy
When multiple oocytes can be fertilize by diff males’ spermatozoa, it is considered?
Superfecundation
Queens are what type of ovulators?
Induced
What is the additional phase in the estrous cycle of the queen that’s after ovulation but before copulation?
Postestrus
What is constant in postestrus?
Follicular phase
How long is postestrus?
8 days
Before postestrus, what phase comes in the queen?
Estrus
What does copulation cause in queens?
An LH surge
Do queens go through lactation anestrus?
No
What is the gestation length in queens?
63 days
Why is there no negative feedback in the queens estrus?
Because there is no corpus luteum to produce progesterone
What are the hormone levels in queen’s postestrus?
Low estradiol and progesterone
Some species that are induced ovulators:
Alpacas, llamas, queens
During anestrus, which hormones drives the negative feedback?
progesterone
What are the 4 causes of anestrus?
Lactation, season, instinct, negative energy balance/nutrition, disease
In seasonal anestrus, what needs to occur to ovulate?
Progesterone and sensitivity to estradiol
What hormone does calf suckling stimulates a surge in?
Lh
What are some species that experience lactational anestrus?
SowS
Which species have no lactational anestrus?
Mares, dairy cattle, alpacas
