Difference between revisions of "Egg Incubation Physiology - Anatomy & Physiology"
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+ | <big><center>[[Reproductive System|'''BACK TO REPRODUCTIVE SYSTEM''']]</center></big> | ||
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+ | <big><center>[[Reproductive_System#Exotics|'''BACK TO EXOTICS''']]</center></big> | ||
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+ | <big><center>[[Exotics_-_Avian_Reproductive_Anatomy_and_Physiology_-_Anatomy_%26_Physiology|'''BACK TO AVIAN REPRODUCTIVE ANATOMY & PHYSIOLOGY''']]</center></big> | ||
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== Changes in Composition of the Egg during Incubation == | == Changes in Composition of the Egg during Incubation == | ||
*As the embryo grows within the egg, the composition of the egg changes. | *As the embryo grows within the egg, the composition of the egg changes. | ||
− | * Both [[ | + | * Both [[Exotics_-_Composition_of_the_Egg_-_Anatomy_%26_Physiology#Yolk|yolk]] and albumin diminish. |
− | ** Yolk providing energy for growth and maintenance of the embryo. | + | ** [[Exotics_-_Composition_of_the_Egg_-_Anatomy_%26_Physiology#Yolk|Yolk]] providing energy for growth and maintenance of the embryo. |
− | ** Albumin providing protein for the embryo and giving up water, which is lost through pores in the | + | ** Albumin providing protein for the embryo and giving up water, which is lost through pores in the shell. |
* Water is produced when yolk fat is oxidised. | * Water is produced when yolk fat is oxidised. | ||
* Water lost from the egg is replaced by air, creating the 'air cell' at the blunt end of the egg. | * Water lost from the egg is replaced by air, creating the 'air cell' at the blunt end of the egg. | ||
− | * Embryo punctures the [[ | + | * Embryo punctures the [[Exotics_-_Composition_of_the_Egg_-_Anatomy_%26_Physiology#Embryonic_Membranes|chorioallantoic]] and [[Exotics_-_Composition_of_the_Egg_-_Anatomy_%26_Physiology#Shell_membranes|internal shell membrane]]. |
** Able to begin pulmonary ventilation, rebreathing the 'air cell' gas. | ** Able to begin pulmonary ventilation, rebreathing the 'air cell' gas. | ||
− | ** Transition from diffusive respiration through the [[ | + | ** Transition from diffusive respiration through the [[Exotics_-_Composition_of_the_Egg_-_Anatomy_%26_Physiology#Embryonic_Membranes|chorioallantois]] to breathing through the lungs. |
+ | ---- | ||
== Heat Transfer to the Egg == | == Heat Transfer to the Egg == | ||
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* Transfer of heat from the body to the egg is the most important contribution of the incubating adult to incubation. | * Transfer of heat from the body to the egg is the most important contribution of the incubating adult to incubation. | ||
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** This is 1.1-5.5ºC higher than the egg temperature. | ** This is 1.1-5.5ºC higher than the egg temperature. | ||
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− | * Heat loss from the egg is prevented by a thin boundary layer of air adjacent to the | + | * Heat loss from the egg is prevented by a thin boundary layer of air adjacent to the shell. |
* If the egg is in a nest, the nest will also provide resistance to heat loss. | * If the egg is in a nest, the nest will also provide resistance to heat loss. | ||
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Revision as of 12:24, 22 July 2008
Changes in Composition of the Egg during Incubation
- As the embryo grows within the egg, the composition of the egg changes.
- Both yolk and albumin diminish.
- Yolk providing energy for growth and maintenance of the embryo.
- Albumin providing protein for the embryo and giving up water, which is lost through pores in the shell.
- Water is produced when yolk fat is oxidised.
- Water lost from the egg is replaced by air, creating the 'air cell' at the blunt end of the egg.
- Embryo punctures the chorioallantoic and internal shell membrane.
- Able to begin pulmonary ventilation, rebreathing the 'air cell' gas.
- Transition from diffusive respiration through the chorioallantois to breathing through the lungs.
Heat Transfer to the Egg
- Transfer of heat from the body to the egg is the most important contribution of the incubating adult to incubation.
- Most birds develop a seasonal bare patch of skin known as the 'brood patch' on part of the thorax and abdomen.
- 'Brood patch' is in direct contact with the egg to permit a greater heat transfer than if there were feathers between them.
- At the same time, there is an increase in the size and number of blood vessels in the bare skin.
- Serves to increase heat transfer, as hot blood runs closer to the surface.
- Adult can adjust the rate of heat transfer by:
- Standing or leaving the egg.
- The closeness with which the 'brood patch' is applied to the egg.
- Responding physiologically to the temperature of the egg, thus increasing or decreasing metabolic heat production.
- 'Brood patch' temperature is 34.9-42.4ºC.
- This is 1.1-5.5ºC higher than the egg temperature.
- Heat loss from the egg is prevented by a thin boundary layer of air adjacent to the shell.
- If the egg is in a nest, the nest will also provide resistance to heat loss.