Case 2a: Sperm

Question 1

Does reproduction vary between species?

Answer 1

yes

Question 2

what is a spermatozoid?

Answer 2

male gemete that is very small and mobile, produced in large numbers

Question 3

what is an oocyte?

Answer 3

female gamete, large and immobile, only produced intermittently

Question 4

what is the estrus cycle?

Answer 4

period between two ovulations

Question 5

what are the four phases of the estrus cycle?

Answer 5

proestrus, estrus, metestrus, diestrus

Question 6

What is proestrus?

Answer 6

period in which one of the largest antral follicles located in ovary develop into Graffian follicles, ovaries are under influence of FSH

Question 7

What is estrus?

Answer 7

period in which the female shows estrus behaviour and allows mating and during or shortly after which ovulation of the Graafian follicle occur, released oocyte is fertilized

Question 8

What is metestrus?

Answer 8

remains of the graafian follicles luteinize under influence of LH, corpus luteum is formed (produces progesterone)

Question 9

What is diestrus?

Answer 9

longest period and is characterized by presence of functional corpus luteum in ovaries

Question 10

What is the transition from diestrus to proestrus characterized by?

Answer 10

regression of corpus luteum (if not pregnant)

Question 11

What is the exception to the ovarian cycle for rabbits/cats?

Answer 11

do not spontaneously ovulate, but show reflex response to mating

Question 12

What is the exception of the ovarian cycle with regards to bony fish?

Answer 12

Three types of ovarian cycles in bonefish
- All present oocytes mature simultaneously and no young oocytes are present in ovary before mating season
- Two developmental stage of oocytes are present during spawning, both large mature oocytes and large number of small oocytes
- Oocyte development proceeds asynchronous, ovary contains almost all phases of oocytes development shortly before spawning period

Question 13

What is the exception to the ovarian cycle with regards to chickens?

Answer 13

formation of chicken egg takes 25-26 hours, 30 mins after egg laying, a new ovulation occurs, but only if LH surge by pituitary has taken place 8 hours before, LH surges only happen in the dark so there will be a skipped day of no egg laying

Question 14

Where does spermatogenesis occur?

Answer 14

testes

Question 15

Why are testes located outside of the body for most species?

Answer 15

Testes located outside the body in the scrotum since spermatogenesis can only occur at temperatures lower than body temperature

Question 16

What is the exception to the testes location and why?

Answer 16

Elephant, rooster, birds, fish: testes located inside abdominal cavity when spermatogenesis can occur at body temp for these species

Question 17

What happens to spermatogenesis if semen production is continuous?

Answer 17

If semen production is continuous spermatogenesis is significantly higher during the breeding season

Question 18

What is the ratio of semen discharged into female tract compared to number of oocytes?

Answer 18

Number of sperm cells that is discharged into the female repro tract during mating is many times greater than the number needed to achieve max fertilization results

Question 19

What is a special characteristic about stallion and boar semen?

Answer 19

produce a lot of semen with relatively low semen concentration

Question 20

What is sexual maturation?

Answer 20

developmental process in both sexes, in which the gonadal hormones play a
stimulating role in the development of the reproductive tract and secondary sexual characteristics

Question 21

When are animals ready for reproduction?

Answer 21

male: first ejaculate w fertile semen
female: first visible signs of estrus

Question 22

What are the exogenous factors that influence sexual maturation?

Answer 22

ambient temperature
feed
day length
intensity of light

Question 23

What are the endogenous factors that influence sexual maturity?

Answer 23

related to genetic predisposition of animal and physiological changes within animal

Question 24

When do chickens first lay their egg?

Answer 24

126 days old

Question 25

When do cattle have their first estrus?

Answer 25

7-10 months

Question 26

When do pigs first show sign of estrus?

Answer 26

200 days

Question 27

Why is it difficult to discuss fish sexual maturity?

Answer 27

Such a large variation in reproductive mechanisms, some fish are born very sexually mature while others not

Question 28

What influences chickens sexual maturation?

Answer 28

light plays an important role, longer days promote maturity

Question 29

What is the time period for fertilization with chickens?

Answer 29

Chicken ovulates frequently and male semen has a long lifespan, up to 10 days, eggs can be laid from one mating

Question 30

How is semen deposited in the cow and ewe?

Answer 30

cranial part of vagina

Question 31

How is semen deposited in the pigg and horse?

Answer 31

cranial part of the cervix and directly in the uterus

Question 32

How is semen deposited in chickens?

Answer 32

The cloaca of the rooster will be pressed against the cloaca of the chicken

Question 33

How is semen deposited within fish?

Answer 33

fertilization can be internal or external - internal: sperm cells are deposited in female tract - external: certain form of synchronization, deposition of oocytes and sperm cells in a location

Question 34

Where does fertilization take place in the cow, ewe, sow and mare?

Answer 34

in the ampulla, close to uterus

Question 35

Where does fertilization take place in chickens?

Answer 35

funnel-shaped ovarian end of the oviduct (infundibulum)

Question 36

What is capacitation and what animals must undergo it?

Answer 36

bull, ram, boar and stallion maturation process of the sperm

Question 37

Where does capacitation occur and how long does it take?

Answer 37

in the female genital tract, lasts 2-6 hours

Question 38

What are the three types of embryos?

Answer 38

viviparous, oviparous, ovoviviparous

Question 39

What is a viviparous animal?

Answer 39

new individual develops in the uterus of the mother during gestation and is fully dependent on the mother in terms of nutrient and oxygen supply

Question 40

What is an oviparous animal?

Answer 40

whether or not internally fertilized, oocytes develop outside the body of the mother, and embryos extract nutrients from the yolk present in the egg

Question 41

What is an ovoviviparous animal?

Answer 41

development of the embryo into a new individual occurs in the mother, but within egg membranes and from nutrients stored in the egg yolk

Question 42

What happens in an extra uterine pregnancy?

Answer 42

embryo develops in the oviduct or abdominal cavity after lost oocyte is fertilized by a sperm cell escaped from oviduct

Question 43

What happens in brood care in fish?

Answer 43

fertilized oocytes are brought together in nest and kept in mouth or stuck to body of parents and carried until fish leave membrane

Question 44

What happens after fertilization?

Answer 44

conceptus is transported to the uterus by contractions of the myometrium of the oviduct and movement induced by cilia at the epithelium of the oviduct; concepts attach/implants to the uterine endometrium

Question 45

What happens to the graafian follicle after ovulation?

Answer 45

corpus luteum develops from remnants of Graafian follicle

Question 46

What is the lifespan of the corpus luteum?

Answer 46

14-16 days and produces progesterone

Question 47

What happens to the corpus luteum if ovulated oocytes has occurred?

Answer 47

life span of corpus luteum is extended, progesterone is essential to establish and maintain favourable intra uterine environment for conceptus

Question 48

How does rescue of the corpus luteum occur?

Answer 48

signals from embryo (maternal recognition of pregnancy)

Question 49

What is the minimum duration of implantation for the mare?

Answer 49

55 days

Question 50

What happens after fertilization in the chicken?

Answer 50

oocyte present in fertilized chicken egg already divided a number of times during passage through the ovidduct, whether embryo grows into chick depends on if it is incubated

Question 51

How is birthing process initiated?

Answer 51

corticosteroids from fetal adrenal gland, related to stress at end of pregnancy (no space/nutrition)

Question 52

What are some problems during birthing in the cow/ewe?

Answer 52

wrong position of the fetus or too high birthweight in relation to pelvic dimensions

Question 53

How are calves and lambs typically born?

Answer 53

head first with head laying on the forwardly stretched front legs

Question 54

Can piglets be born head or tail first without much issue?

Answer 54

yes

Question 55

How many days until a chick hatches from egg?

Answer 55

21 days after incubation

Question 56

Are all sows inseminated artifically in the netherlands?

Answer 56

yes, increases efficiency and genetic progress

Question 57

How many times is semen collected per each boar per week/

Answer 57

1-2 times per week

Question 58

How many days is boar semen used after collection?

Answer 58

2-3 days

Question 59

When are sows inseminated?

Answer 59

1-2 days into estrus

Question 60

How long does ejaculation last?

Answer 60

8-9 minutes and can deliver 100-500 ml of semen

Question 61

What are the fractions of the boar semen?

Answer 61

first 20 ml is water semen that isn't collected milky white semen (must be collected) watery liquid

Question 62

What is the gel fraction of boar ejaculate?

Answer 62

prevents backflow of semen from the uterus