avian reproduction male system Flashcards
testes
- internal
- produce male gametes and hormones
testes structure
- capsule - lots of connective tissue
- tunica albuginea
- tunica serosa
- tunica vasculosa
fuctional tissues: - interstitial tissue (blood vessels, nerves and leydig cells)
- seminiferous epithelium
- seritoli and germ cells
male reproductive tract
- rete testis, vasa efferentia - sperm maturation in efferent duct
- epididymis
- very small and short in birds ( not a storage site like in mammals - very little sperm maturation)
- vas deferens - storage site for sperm, terminate at a papilla in the cloaca
accessory sex organs
- no seminal vescicles, prostate gland or bulbourethral glands
- paracloacal vascular bodies
- forms lymph ( dorsal protodeal gland, lymphatic folds)
- true seminal plasma (small amount)
- transparent fluid, clear, watery)
male copulatory organ
- cloacal floor
- erectile fluid is lymph
- not intromittent organ
male reproduction
- development of reproductive organs
- photoperiod
- age (sexual maturity)
- temp
- FSH - growth differentiation and spermatogenis activity of seminiferous tubules
- LH - steridogenis activity ( testosterone production)
semen
sperm cells, true seminal plasma and transparent fluid, proctodeal gland fluid
- usually viscous and milky white
sperm morphology
- long cylindrical and tapered at both ends
- no sperm capacitation required (acrosomal distruction like in mammals)
laying sequence
- period of 1 or more days of consecutive laying
- each egg in a sequence occurs slightly later each day
- prime sequence: the longest laying sequence of a he n
- usually occurs about the time of peak production
- lag: the difference (in hours) between the laying of eggs in a laying sequence
- long lag times are related to slow rates of follicular maturation and results in short sequences
broodiness
incubation period behaviour is the hens natural tendency to cease laying and incubate a clutch of eggs
Hormonal control:
- relationship to reproductive cycle
- progesteron decrease: nest entry
- prolactin increases: initiation of brooding behaviour in conjunction with decrease in ovarian steroids
- maintenance of brooding behaviour
enviromental factors effecting broodiness
- high ambient temperatures increase hypothalamic vasoactive intestinal peptide content
- low light intensity
- isolation
- physical contact of the brood patch on chest
brood patch
- featherless skin on underside of bird
- allows for heat transfer directly onto eggs or onto floor to warm eggs
methods to control broodiness
- environmental management: walking around, removing broodi hens, high light insensity
- genetic selection
- vaccines against VIP
natural mating
- domesticated birds are generally polygamous
- roosters mate up to 30 times per day
- mating is more frequent in the afternoon
- usually a 1 to 10 male to female ratio
natual mating sequence
- bite neck and scratch back
- female moves tail
- male drops in adn cloaca touch
- semen goes in and vagina retracts to prevent bacteria entering
- cloaca kiss
artificial insemination
- commercial turkey industry ( to large to mate without hurting the females
- genetic selection of poultry
0 zoos and other institutions trying to reproduce rare and expensive birds
semen collection technique
- normally pooled prior to insemination
- semen extenders or diluents can be used (turkeys)
- buffer acid production by bacteria and enhance fertility
- extend the volmune of semen
semen evalutation
- colour (pearly white, no yellow = contamination)
- volume
- viscosity
- spermatozoa concentration
- sperm motility
- live-dead stain (all dead sperms will stain)
insemination procedure
- avoid insemination at or for two hours after oviposition
- frequency chickens - 5-7 days, turkeys 7 or more days
- inseminate within 30-45 minutes of semen collection
- short term storage
- freezing semen = lowers fertility
