Midterm 3 - Lecture 26

Question 1

How do chickens mate?

Answer 1

• vas deferens ejects semen into cloaca
• folds of female cloaca swell during mating and allow semen transfer through cloacal contact
• female everts cloaca to make better contact with ejaculate
• less “courtship” behaviour- more forced copulation

Question 2

Do avians display courtship behaviours?

Answer 2

• not really; more forced copulation

Question 3

What do sexually active male look like?

Answer 3

• scruffy

Question 4

When are roosters most sexually active?

Answer 4

• at the beginning and especially end of the day
• assess mating behaviour at a time when males should be actively mating

Question 5

What is fertility of the flock based on?

Answer 5

Activity of the roosters

Question 6

When does rooster/flock fertility decline?

Answer 6

with age

Question 7

How is rooster/flock fertility related to age?

Answer 7

• declines with age
• natural relationship btw bird behaviour and physiology
• rooster less interested and able to complete mating
• hen physiologically needs to be mated more often to sustain same level of fertility

Question 8

How is a Rooster Spiking Program implemented?

Answer 8

• To keep fertility since it is almost impossible to maintain early fertility in a +40 wk old flock
• add 2% 28 wk old males to a flock at 40-45 wk of age

Question 9

What does a Rooster Spiking Program achieve?

Answer 9

• reactivate/motivate older males
• young males will increase the overall mating frequency in the flock (second string)
• adds 3-6 chicks/hen to flock production
• old male activity declines 6-9 weeks after spiking

Question 10

How is chicken and turkey breeding different?

Answer 10

Turkeys: AI
Chickens: natural breeding

Question 11

What are 2 roles of the sperm storage tubules?

Answer 11

1. Select sperm
2. Store sperm

Question 12

Where are the sperm storage tubules located? What do they do?

Answer 12

• located just inside the shell gland
• provide a micro-enviro in which sperm can survive and retain fertility
• play a role in sperm selection

Question 13

Is sperm storage time different for different species?

Answer 13

yes

Question 14

Why is sperm stored?

Answer 14

• ability to store sperm eliminates the need to synchronize mating with ovulation
• reduced mating frequency = less susceptible to predators
• fertility extended during SST

Question 15

In chickens, how long is fertility extended during SST storage?

Answer 15

~6 days = full fertilizing capacity
10 days = ~50% eggs are fertilized
19 days = ~15% eggs are fertilized

Question 16

If a hen is inseminated with 150 million sperm, what percentage makes it to the SSTs?

Answer 16

• 1-2% reach SSTs
• 84% lost in feces within 30 min
• 90% can’t pass through vagina

Question 17

How does interaction with the hen’s tract determine sperm fate?

Answer 17

• sperm selection starts with interaction with luminal fluids on way to SST
• hen’s “vagina” have cilia that beat and move fluids and debris toward the cloaca

Question 18

How do sperm enter SST?

Answer 18

motility and cilia action

Question 19

What are the characteristics of the SST microenvironment?

Answer 19

• suppresses O2 uptake and motility = REST
• inhibits enzyme systems
• stabilizes plasma membrane

Question 20

What ‘type’ of sperm are selected to be stored?

Answer 20

the youngest and most “fit”

Question 21

How long does it take to fill SST in chickens vs turkeys?

Answer 21

Chicken = 1 day
Turkey = 2 day

Question 22

What is the last male precedence theory?

Answer 22

• theory suggests that the male who completes the most recent insemination is most likely to successfully fertilize the next egg
• assumes that a fresh ejaculate will provide fit/viable sperm and preferentially fill the SST

Question 23

Is the last male precedence theory true?

Answer 23

no

Question 24

What defines which sperm fill the SST and fertilize?

Answer 24

• order of insemination did not dictate which sperm populated the SST
• quality of the sperm defines which wiill fill
• if inseminated by 2 males 24hrs apart, sperm from the different males were not both found in the SSTs

Question 25

What is the criteria for SST selection of sperm?

Answer 25

1. sperm with low motility are rejected
2. recognition of sperm via proteins on sperm plasma membrane
3. species-specific immunological barrier

Question 26

What is sperm survival in SST dependent on?

Answer 26

1. production of fatty acids by SST epithelium for energy used by sperm
2. prevention of damage to the sperm plasma membrane
3. removal of sperm catabolism products from the luminal fluids via membrane proteins at the blind ends of SSTs

Question 27

Why must sperm in the SST remain motile?

Answer 27

to remain “parked” and prevent from being flushed out by release of fluid produced by SST epithelium

Question 28

What is the site of fertilization?

Answer 28

infundibulum

Question 29

Continuous Release Model

Answer 29

• theory suggests that some sperm are constantly being released into the oviduct
• supported by the fact that the # of sperm in the SST is reduced at a continuous rate regardless if ovulation occurs or not
• motile/fit sperm enter folds in the female tract and are moved up to the site of fertilization by localized contractions