Difference between revisions of "Avian Breeding, Ovulation and Oviposition - Anatomy & Physiology"
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== Breeding Cycles == | == Breeding Cycles == | ||
* Classified according to length of cycle and the time of year when the species becomes reproductively active. | * Classified according to length of cycle and the time of year when the species becomes reproductively active. | ||
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* '''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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== Ovulation== | == Ovulation== | ||
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* Once ovulation has taken place, the [[The_Ovary_-_Follicles_- Anatomy & Physiology|follicle]] shrinks and regresses. | * Once ovulation has taken place, the [[The_Ovary_-_Follicles_- Anatomy & Physiology|follicle]] shrinks and regresses. | ||
* '''No [[The_Ovary_-Corpus_Luteum_- Anatomy & Physiology|corpus luteum]]''' remains, as there is no developing embryo to maintain. | * '''No [[The_Ovary_-Corpus_Luteum_- Anatomy & Physiology|corpus luteum]]''' remains, as there is no developing embryo to maintain. | ||
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== Oviposition == | == Oviposition == | ||
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* Minutes to hours | * Minutes to hours | ||
** Cuckoos lay their eggs in seconds so they can get away before the host returns. | ** Cuckoos lay their eggs in seconds so they can get away before the host returns. | ||
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== Post-Lay == | == Post-Lay == | ||
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| − | [[Category: | + | [[Category:Avian Reproduction]] |
Revision as of 17:08, 29 November 2010
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.
Oviposition
- Expulsion of the egg
- Contraction of the 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.