2. reproduction in birds Flashcards
what are the components of the avian male reproductive tract
- paired testes
- duct system (epididymis and ductus deferens
- +/- phallus
discuss the testis of birds
- large in comparison to mammals
- increase in size when sexually active
- left larger than right
- intraabdominal
- cranioventral to first kidney love, near abdominal air sac
- spermatogenesis therefore better at cooler temperatures (mornings)
discuss the duct system in avian males
- small epididymis
- highly coiled ductus deferens which terminates in urodeum on papilla (site of sperm maturation)
discuss how testes in breeding vs non-breeding avian males change
- can increase in size 300-500 fold
- colour changes from yellow-brown to white
- ductus deferens more convoluted
- seminal glomus = sperm strage
discuss the phallus in birds
- varies by spp
- erection lymphatic, not vascular
- semen transfer by cloaca to cloaca contact
discuss the ovaries in the avian female reproductive system
- left ovary is functional
- right not (vestigial) unless left removed
- looks like a bunch of grapes
- yellow: single cell with huge lipid inclusion
- rapid follicular development
- hierarchy of maturation
- usually 10 yolky follicles, large number of small yellow follicles
- numerous smaller white follicles
avian oocytes have zona pellucida true or false
false
discuss the endocrinology of the hen
- FSH responsible for follicular growth
- follicles produce: oestrogen from theca cells and interstitial cells
- progesterone from granulosa cells
- opposite of mammal
- increasing oestrogen triggers LH surge and oocyte release
the increase in oestrogen causes what events to occur in preparation for egg laying
- synthesis of calcium ATPase (in shell gland)
- long bone medullary spaces calcified
- very low density lipoproteins produced and transported to ovary (precursor of yolk)
- oviduct enlarges
- plumage, comb size and sexual receptivity change
which hormones are high prior to ovulation in the bird
- progesterone
- LH
- high progesterone is trigger for LH release and therefore ovulation
do birds have a corpus luteum
no - dont need one as dont maintain pregnancy to give birth to live young (development occurs in the egg outside the body)
what is egg peritonitis
- ovum misses the infundibulum
- yolk free in coelomic cavity
- caused by oviduct pathology, stress and obesity
outline the pathway of an egg through the hen and how long it takes to produce an egg
- infundibulum: <1hr
- magnum : >3 hrs
- isthmus: 1-1 1/2 hrs
- uterus/shell gland: 20 hrs
- vagina and cloaca: seconds to hours
the infundibulum in the bird does what
- secretes chalazae (whitish string like structures)
- holds yolk in position during development
what happens to the egg in the magnum
albumin laid down around the oocyte
