320 Exam 2 Reproductive cyclicity

What is teh importance of reproductive cyclicity

provides the female with repeated opportunities to become pregnant

What are the different types of reproductive cyclicity?

polyestrus, seasonally polyestrus, and monoestrus

What is a polyestrus cycle and examples

multiple times troughout year: cow, queen, pig ,rodents

what is seasonal polyestrus cycle (long day) and examples

Spring breeding season only: mare

What is seasonal polyestrus (short day) and examples

Fall breeding season: ewe, doe, elk, nanny

What is monoestrus and examples?

one longer estrus per year: dog, wolf, fox, bear

What are teh 4 period of the estrous cycle?

Estrus, metestrus, diestrus, and proestrus

What is Estrus?

-period of sexual receptivity and mating

-Estradiol is the dominant hormone

-12-18hrs in cow

What is metestrus?

period between ovulation and the formation of a functional CL

-ovulation 27-30hrs after start of estrus

-CH to CL formation

-progesterone rises

-metestrus bleeding

What is metestrus bleeding?

capillary breakage due to decreased estrogen ()% of heifers 45% of cows

What is diestrus?

Period for preparing the uterus for pregnancy

-functional CL

-high levels of progesterone

What is proestrus?

Begins with Cl destruction and terminates at the beginning of estrus

-major endocrine transition

-progesterone declines

-rapid follicle growth

-estradiol increases

When does E2 rise and fall through the estrous cycle?

rises during proestrus and falls during metestrus.

When does GnRH-LH rise and fall through the estrous cycle?

Rises at the end of proestrus and falls during the beginning of metestrus

When does P4 rise and fall through the estrous cycle?

rises during metestrus and falls during proestrus

When does PGF@a rise and fall through the estrous cycle?

rises during diestrus and proestrus before estrus

When does tonic secretion of LH rise and fall through the estrous cycle?

Rises and falls intermittently between metestrus and proestrus

When does FSH rise and fall through the estrous cycle?

Rises during estrus and falls at the beginning of metestrus, surges before diestrus.

Wild canids are receptive to males when?

during declining estrogen and rising progesterone.

What extra phase do queens have in their cycle?

Postestrus -period following estrus, id the cat does not ovulate because they are induced ovulators

What is anestrus?

when cyclycity stops due to a number of things (pregnancy, parturition, uterine involution, lactation, offspring presence, season of teh year) could also happen due to increased stress of pathological conditions

What is Pregnancy or gestational Anestrus?

progesterone during pregnancy, negative feedback, hypothalamus-GnRH

anterior pituitary-LH

after parturition anestrus continues which llows time for uterine involution

What is the purpose of lactation induced anestrus?

Prevents new pregnancy before weaning young

What is the goal?

to get a calf every 365 days