Lecture 2

Question 1

Which animals do and do not have reproductive cycles that are affected by photoperiod?

Answer 1

Affected:
-mare
-doe
-ewe
-queen

Not Affected:
-cow
-sow
-bitch
-llama

Question 2

Which animals are spontaneous ovulators vs induced ovulators?

Answer 2

Spontaneous:
-mare
-doe
-ewe
-cow
-sow
-bitch

Induced:
-llama
-queen

Question 3

What are the characteristics of the follicular phase?

Answer 3

-characterized by follicle development
-increasing estrogen secretion
-changes in repro. tract due to estrogen
-behavioral changes/signs of estrus

Question 4

What are the characteristics of the luteal phase?

Answer 4

-period of the corpus luteum
-resist breeding attempts by male
-decreased uterine tone/uterine quiescence

Question 5

Which stages fall into the follicular phase?

Answer 5

-proestrus
-estrus

Question 6

Which stages fall into the luteal phase?

Answer 6

-metestrus
-diestrus

Question 7

What is the description for each stage of the estrous cycle?

Answer 7

-proestrus: formulation of ovulatory follicles and estrogen secretion
-estrus: sexual receptivity and peak estrogen
-metestrus: period of CL formation prior to significant progesterone secretion
-diestrus: sustained release of progesterone
-anestrous: period of non-cyclic activity

Question 8

What are the characteristics of the mare estrous cycle?

Answer 8

-overall cycle length of 19 to 22 days
-estrus for 5 to 7 days
-diestrus for 14 to 16 days
-shows overt signs

Question 9

What are the characteristics of the cow estrous cycle?

Answer 9

-overall cycle length of 18 to 22 days
-estrus for 6 to 30 hours
-diestrus for 16 to 17 days
-shows overt signs

Question 10

What are the characteristics of the sow estrous cycle?

Answer 10

-overall cycle length of 18 to 22 days
-estrus for 24 to 72 hours
-diestrus for 15 to 17 days
-shows overt signs

Question 11

What are the characteristics of the doe estrous cycle?

Answer 11

-overall cycle length of 18 to 21 days
-estrus for 24 to 36 hours
-diestrus for 15 to 17 days
-shows overt signs

Question 12

What are the characteristics of the ewe estrous cycle?

Answer 12

-overall cycle length of 14 to 18 days
-estrus for 24 to 36 hours
-diestrus for 12 to 13 days
-no overt signs

Question 13

What are the characteristics of the bitch estrous cycle?

Answer 13

-overall cycle length of 60 to 80 days
-estrus for 7 to 9 days
-diestrus for 60 to 80 days
-shows overt signs
-a non-pregnant cycle is followed by a 2 to 5 month period of anestrous

Question 14

What are the characteristics of the llama estrous cycle?

Answer 14

-no defined estrous cycle like other animals
-female is either receptive or non-receptive
-will be receptive following an unsuccessful mating after 15 to 21 days
-follicle regresses and is replaced quickly when receptive but not mated
-remains almost continually receptive until ovulation

Question 15

What are the characteristics of the queen estrous cycle?

Answer 15

-if mating and ovulation do not result in pregnancy, queen is non-receptive for 45 days
-if receptive but not mated follicles will regress after 2 to 3 days
-following receptivity without mating the queen will enter an inter-estrus period of 10 to 14 days before being receptive again

Question 16

What are the estrus behaviors in cows?

Answer 16

-homosexual activity/mounting other cows
-standing still to allow other cows to mount
-decreased milk production
-decreased appetite
-bellowing
-excessive walking
-clear elastic vaginal discharge

Question 17

What are the estrus behaviors in mares?

Answer 17

-squatting
-tail raising
-urinating
-clitoral eversion

Question 18

What are the estrus behaviors in ewes?

Answer 18

-seeking the male
-immobile stance for trial mounting/mounting

Question 19

What are the estrus behaviors in does?

Answer 19

-seeking the male
-some homosexual activity

Question 20

What are the estrus behaviors in sows?

Answer 20

-swollen and congested vulva
-restlessness
-repetitive grunting
-homosexual activity
-rigid stationary position

Question 21

What are the estrus behaviors in the bitch?

Answer 21

-tail deviation to side
-lordosis-like position
-male acceptance
-firm stance

Question 22

What are the estrus behaviors of the queen?

Answer 22

-acceptance of male
-lordosis-like position
-tail deviation
-“calling” the tom

Question 23

What are the estrus behaviors of llamas?

Answer 23

-acceptance of male
-readily adopts sitting position

Question 24

What are the characteristics of follicular development?

Answer 24

-follicles selected in groups from primordial pool
-groups emerge every 8 to 12 days
-most follicles undergo atresia as development proceeds
-development occurs independent of gonadotropin support
-three states of development are growing, static, and regressing
-growth phase includes recruitment, selection, and dominance
-FSH/LH needed for further maturation once antrum formation is reached
-takes 60 to 90 days from initial selection to potential ovulation

Question 25

What are the characteristics of the dominant follicle?

Answer 25

-follicle(s) that survive development process -number that survives depends on species -produce inhibin -finite period of survival

Question 26

What must happen in order to have an LH surge?

Answer 26

-increase in estrogen (E2) -decrease in progesterone (P4)

Question 27

What is the role of LH?

Answer 27

responsible for ovulation and luteinization

Question 28

What is the progression of cells from primordial germ cell to zygote?

Answer 28

PRENATAL: -primordial germ cell -oogonia -primary oocyte POST PUBERTY: -secondary oocyte -zygote

Question 29

What is the role of FSH?

Answer 29

recruit follicles and help them grow

Question 30

Which hormones are produced by growing follicles?

Answer 30

-estradiol -inhibin

Question 31

How does progesterone affect LH?

Answer 31

high progesterone will maintain a low LH level

Question 32

What does GnRH trigger the secretion of?

Answer 32

-FSH -LH

Question 33

Which hormones are involved in the control of estrus?

Answer 33

-melatonin -GnRH -FSH -LH -estradiol -inhibin -progesterone -oxytocin -prostaglandin

Question 34

How does the dominant follicle respond to LH?

Answer 34

by changing its growth receptor from recognizing FSH to recognizing LH