Difference between revisions of "Avian Breeding, Ovulation and Oviposition - Anatomy & Physiology"
Jump to navigation
Jump to search
(30 intermediate revisions by 3 users not shown) | |||
Line 7: | Line 7: | ||
* 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. | ||
+ | |||
+ | ---- | ||
== Endocrine Control == | == Endocrine Control == | ||
* In females, '''FSH''' is mainly responsible for follicular growth. | * 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 | + | * 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 | + | * '''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. | * Number of ovulations varies with species, mostly lay one clutch a year. | ||
− | * | + | * Infundibulum catches the oocyte, facillitated by the left abdominal air sac which tightly encloses the ovary. |
− | * Once ovulation has taken place, the | + | * Once ovulation has taken place, the follicle shrinks and regresses. |
− | * '''No | + | * '''No corpus luteum''' remains, as there is no developing embryo to maintain. |
== Oviposition == | == Oviposition == | ||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− |
Revision as of 12:42, 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
- Number of ovulations varies with species, mostly lay one clutch a year.
- Infundibulum catches the oocyte, facillitated by the left abdominal air sac which tightly encloses the ovary.
- Once ovulation has taken place, the follicle shrinks and regresses.
- No corpus luteum remains, as there is no developing embryo to maintain.