Bird reproduction Flashcards
What change occurs to the DD in male birds during breeding season?
Becomes more highly coiled
What is the seminal glomus?
An enlargement of the DD at the distal end–> allows sperm storage. Not all species have it, those who don’t have no sperm storage.
In species with either no phallus or a phallus with no intromission, how does semen transfer occur?
-Cloaca to cloaca
How is an erection achieved in the male bird?
By lymphatic system NOT vascular
When do male birds produce the most semen?
At night when its cooler
Which of the female birds ovaries are functional?
The left
-The right becomes activated if you remove the left.
Describe a bird ovary
- Bunch of grapes appearance
- Yellow single cell which includes high concentration of lipids as lipids become the yolk
- Have no antrum, the entire follicle is filled with yolk
Describe the hierarchy of follicles
- F1, F2 and F3
- F1 is the largest and will be the next to be ovulated
What is different about avarian follicles?
No ZP, membrane granulosa or cumulus
Describe the post ovulatory follicle in the bird
Active granulosa cells secrete non steroidal hormones (responsible for nesting behaviour)
What do the granulosa and theca cells produce in birds?
Granulosa= P4
Theca=E2
Compare the ovulation HPO feedback between mammals and birds
-Mammals
Hypothalamus-> GnRH-> Pituitary-> LH-> Ovary-> E2
-Birds
Hypothalamus-> GnRH-> Pituitary->LH -> F1 ovary -> P4
(so in birds it is P4 increase that is the stimulus for LH surge and ovulation)
In birds what is the open period?
-Window of time for LH release
Describe ovulation in birds
- F1 follicle produces enough P4(during open period) to stimulate LH surge
- Ovulation occurs
- No CL formed (no pregnancy so CL not needed)
Where is sperm stored in female birds? And how long can it be stored?
- At the function of the vagina and shell gland
- 2 weeks
Describe egg production
- Series of albumin coats added in concentric layers (proteins made in magnum and liver)
- Passage of egg causes release of albumin
- Inner/ outer shell membranes made in the isthmus
- Developing egg moves into the shell gland, calcium carbonate added here, then cuticle proteins added
What stimulates release of albumin?
-Passage of the egg
What is the difference between a determinate and indeterminate layer?
- Determinate= fixed number of eggs in a clutch
- Indeterminate= can continue to lay eggs if eggs are removed.
How long after ovulation is an egg laid?
-24-36 hours
What is the hormone that causes broody behaviour?
Prolactin
How is a bird primed?
Must be kept in the dark, if they are exposed to light during the photosensitive period they think it is still ‘long days’. Long days stimulate gonadal regression.
-Photosensitive period= 13-17 hours after dawn.
What are the methods for sexing pet birds?
- DNA via blood from claw clippings
- Surgical endoscopy of gonads
- Faecal steroids
