Difference between revisions of "Avian Breeding, Ovulation and Oviposition - Anatomy & Physiology"
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== 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 follicle to split and release the primary oocyte. | + | * 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. | + | * '''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'''. |
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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.