Difference between revisions of "Avian Breeding, Ovulation and Oviposition - Anatomy & Physiology"

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* Usually lay one or more eggs in a clutch and terminate laying to incubate the eggs.
 
* Usually lay one or more eggs in a clutch and terminate laying to incubate the eggs.
 
* Number of eggs per clutch and total number of clutches vary with species and season.
 
* Number of eggs per clutch and total number of clutches vary with species and season.
 +
 +
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== Endocrine Control ==
 
== Endocrine Control ==
* In females, '''FSH''' is mainly responsible for follicular growth.
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* In females, FSH is mainly responsible for follicular growth.
* Developing follicles produce '''Oestrogen''' from '''Theca and interstitial cells''' and '''Progesterone''' from '''Granulosa cells'''.
+
* Developing follicles produce Oestrogen from Theca and interstitial cells and Progesterone from Granulosa cells.
* Increasing levels of Oestrogen stimulate an '''LH surge''' to cause the [[Follicles - Anatomy & Physiology|follicle]]  to split and release the primary [[Oogenesis - Anatomy & Physiology|oocyte]].
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* Increasing levels of Oestrogen stimulate an LH surge to cause the follicle to split and release the primary oocyte.
* '''Oestrogen mobilizes calcium''' from the bone, increasing plasma concentrations for [[Egg Composition and Formation - Anatomy & Physiology|egg formation]].
+
* Oestrogen mobilizes calcium from the bone, increasing plasma concentrations for egg formation.
* '''Progesterone''' secretion continues to inhibit further ovulation and stimulate behavioural changes associated with '''broodiness and incubation'''.
+
* Progesterone secretion continues to inhibit further ovulation and stimulate behavioural changes associated with broodiness and incubation.
* '''Prolactin''' stimulates the production of '''crop milk''' in male and female columbiformes.
+
* Prolactin stimulates the production of crop milk in male and female columbiformes.
* '''Oviposition''' is controlled by '''prostaglandins and Arginine Vasotocin'''.
+
* Oviposition is controlled by prostaglandins and Arginine Vasotocin.
 +
 
  
 
== Ovulation==
 
== Ovulation==
* Number of ovulations varies with species, mostly lay one clutch a year.
+
 
* [[Avian Female Reproductive System#Infundibulum|Infundibulum]] catches the [[Oogenesis - Anatomy & Physiology|oocyte]], facillitated by the left abdominal air sac which tightly encloses the [[Avian Female Reproductive System#Ovary|ovary]].
 
* Once ovulation has taken place, the  [[Follicles - Anatomy & Physiology|follicle]] shrinks and regresses.
 
* '''No [[Corpus Luteum - Anatomy & Physiology|corpus luteum]]''' remains, as there is no developing embryo to maintain.
 
  
 
== Oviposition ==
 
== Oviposition ==
* Expulsion of the egg
 
* Contraction of the [[Avian Female Reproductive System#Vagina|Uterine shell gland (Vagina)]] with relaxation of abdominal muscles.
 
* Minutes to hours
 
** Cuckoos lay their eggs in seconds so they can get away before the host returns.
 
 
== Post-Lay ==
 
 
* Enters a non-breeding state whilst incubating and caring for the brood.
 
* Resting ovary appears shrunken, similar to the juvenile [[Avian Female Reproductive System#Ovary|ovary]].
 
* [[Avian Female Reproductive System#Oviduct|Oviduct]] regresses into an inconspicous, narrow tube.
 
 
 
 
[[Category:Avian Reproduction]]
 
[[Category:Bullet Points]]
 

Revision as of 12:38, 4 July 2008

Breeding Cycles

  • Classified according to length of cycle and the time of year when the species becomes reproductively active.
    • Continuous breeders are reproductively active throughout the year e.g. Khaki Campbell duck.
    • Most wild species that breed in temperate, subarctic and arctic zones display yearly cycles.
  • Tropical or desert species may breed with cycles less than a year, at 6-month intervals or when conditions are favourable (opportunistic breeders).
  • Usually lay one or more eggs in a clutch and terminate laying to incubate the eggs.
  • Number of eggs per clutch and total number of clutches vary with species and season.

Endocrine Control

  • In females, FSH is mainly responsible for follicular growth.
  • Developing follicles produce Oestrogen from Theca and interstitial cells and Progesterone from Granulosa cells.
  • Increasing levels of Oestrogen stimulate an LH surge to cause the follicle to split and release the primary oocyte.
  • Oestrogen mobilizes calcium from the bone, increasing plasma concentrations for egg formation.
  • Progesterone secretion continues to inhibit further ovulation and stimulate behavioural changes associated with broodiness and incubation.
  • Prolactin stimulates the production of crop milk in male and female columbiformes.
  • Oviposition is controlled by prostaglandins and Arginine Vasotocin.


Ovulation

Oviposition