Reproduction in Birds Flashcards
Do avian males have accessory glands?
No
How are the testes in avian species different?
Larger by comparison (increase 500x when active), intrabdominal, epididymis is small, highly coiled ductus deferens
What is the seminal glomus?
Part of the ductus deferens, used for sperm storage, only found in some species
What three types of phallus can be found in birds?
No phallus, phallus (no intromission), phallus (intromission)
When does spermatogenesis occur?
At night, cooler temperatures
How is sperm transferred usually?
Cloaca to cloaca contact
Which ovary is functional?
Left ovary, right activated if left ovary removed
What do the developing follicles contain?
Oocytes with yolk, granulosa and theca cells
How is the egg released?
Follicle splits open to release egg
What hormones are produced by avian granulosa and theca cells?
Granulosa produce progesterone, theca convert progesterone into oestrogen
What processes in preparation for eff laying is oestrogen involved in?
Calcium ATPase, medullary spaces calcified, VLDL (yolk), oviduct enlarges, secondary sex characteristics (plumage, comb size, receptivity)
What is the main endocrine difference of developing ovaries in birds?
Produce progesterone (compared to oestrogen in mammals)
What is the open period?
Window of time for LH release, from onset of darkness until 1 hour after onset of light
What must happen for ovulation to occur?
F1 follicle must produce enough progesterone during open period
How are the events preceding ovulation different?
No CL formed
What is the function of the sperm storage tubules?
Store sperm for 10-14 days, squeeze out sperm that can migrate and fertilize another egg
What part of the egg is formed in each area of the reproductive tract?
Infundibulum – chalaze
Magnum – albumen
Isthmus – inner and outer shell membranes
Uterus/shell gland – shell, cuticle, (pigment)
Vagina and cloaca - oviposition
When is an egg laid in relation to ovulation?
24-26 hours after
Describe the endocrinology of brooding
Progesterone inhibits more ovulation
Reproductive tissues regress
LH, oestrogen & progesterone decrease
Prolactin increases
What is caused by the increase in prolactin?
Nesting activity and incubation, gonadal regression, parental care
What is the function of the defeathered oedematous brood patch?
Keeps eggs warm when brooding
What environmental factors are key in reproductive birds?
Access to a nest box & a mate
Photostimulation in seasonal breeders
Light exposure (photosensitive phase)
What are the genetics of sexes in birds?
Female – ZW, male – ZZ
What methods can be used to sex birds?
DNA, endoscopy, faecal hormones
