Day 1: Reproductive Cyclicity, Terminology, and Basic Concepts

What are the two types of reproductive cycles in mammals?

estrous, menstrual

The series of reproductive events beginning at estrus is known as _______________.

estrous cycle

Period of sexual receptivity in the female.

estrus

What three things can disrupt the estrous cycle throughout a female's life?

pregnancy, nursing, season

The period when cyclicity stops is known as what?

anestrus

Copulation generally occurs ___________ ovulation.

prior to

When pregnancy occurs, the female enters a period of anestrus which ends after what?

parturition, uterine involution, lactation

Return to normal uterine size and function is known as?

uterine involution

What two layman's terms may be used to refer to estrus?

heat, season

What are the three types of estrous cyclicity?

polyestrus, seasonally polyestrus, monoestrus

Animals that have multiple estrous cycles during a breeding season or annually, have what type of cyclicity?

polyestrous

Animals that have multiple estrous cycles within a specific season, influenced by factors like daylight hours, have what type of cyclicity?

seasonally polyestrous

Animals that typically have one estrous cycle annually are known as what?

monoestrous

What are some examples of polyestrus animals?

cattle, swine, rodents

What are some examples of seasonally polyestrus species?

sheep, mare, cats

What are some examples of mononestrus species?

dogs, bears

What animals are "short day" breeders? (cycle in the fall)

sheep and goats

What animals are "long day: breeders? (cycle in the spring?

mares, queens

How many estrous cycles does the typical domestic canid have every 3 years?

3 cycles every 2 years

How many estrous cycles does the non-domestic canid have every 3 years?

?

What phase constitutes 20% of the estrous cycle?

follicular

What phase constitutes 80% of the estrous cycle?

luteal

What is the primary ovarian structure of the follicular phase?

large growing follicles

What is the primary ovarian structure of the luteal phase?

corpora lutea

What is the primary hormone of the follicular phase?

estradiol

What is the primary hormone of the luteal phase?

progesterone

What are the four stages of the estrous cycle?

proestrus, estrus, metestrus, diestrus

What phase occurs during proestrus and estrus?

follicular

What phase occurs during metestrus and diestrus?

luteal

Formation of ovulatory follicles and estrogen secretion is characteristic of what phase of the estrous cycle?

proestrus

Sexual receptivity and peak of estrogen secretion is characteristic of what phase of the estrous cycle?

estrus

Corpus luteum formation and beginning of progesterone secretion is characteristic of what phase of the estrous cycle?

metestrus

Sustained luteal secretion of progesterone is characteristic of what phase of the estrous cycle?

diestrus

What are the primary behavioral characteristics associated with sexual receptivity?

movement, phonation, nervousness, mounting

What are the secondary behavioral characteristics associated with sexual receptivity?

lordosis

What is the longest stage of the estrous cycle?

diestrus

______________ describes when multiple ovulations produce multiple oocytes in a single estrus.

superfecundation

Superfecundation allows for fertilization by sperm from different males. True/False

True

What animals exhibit superfecundation?

sheep, dogs, cats

What factors can trigger anestrus?

environment, illness, pregnancy, season, lactation, negative energy balance

Mnemonic for factors that can trigger anestrus.

every ill penguin suffers low nutrition

What hormonal changes occur just before partruition?

decrease in progesterone, increase in estrogen and oxytocin

What is the suggested explanation for some species experiencing seasonal anestrus?

photoperiod influence on pineal gland secretion of melatonin

Ovulation that occurs without the typical behavioral signs is known as what?

silent ovulation

In silent ovulation, what hormone is decreased?

progesterone

What are some species that more commonly exhibit silent ovulation?

cattle, primates

What is the fundamental difference between short-day and long-day breeders?

responsiveness of kisspeptin to RFRP3

Repeated administration of _______ inhibits the HBG axis and leads to reduced LH pulse frequency.

RFRP3

What decreases the effects of RFRP3 inhibition during short days?

melatonin

The reduction of RFRP3 influence due to melatonin in short day breeders results in what?

increase in GnRH and subsequent increase in LH and FSH

The reduction of RFRP3 influence due to melatonin in long day breeders results in what?

decrease in GnRH and and termination of FSH and LH secretion

Mammary stimulation is solely responsible for lactation anestrus. T/F

False

What are two species that do not experience lactational anestrus?

horse, alpaca

What are some factors that may be responsible for inhibition of GnRH during the postpartum period?

suckling, and visual, olfactory, or auditory encounter with offspring

What does primiparous mean?

first pregnancy

Why is optimal nutrition crucial for primiparous lactating heifers?

restricted dietary intake is compounded by the high energy requirements for lactation and growth