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Feather - Anatomy & Physiology (view source)
Revision as of 10:47, 16 July 2008
, 10:47, 16 July 2008→Moult
*continual - e.g. powder down
*continual - e.g. powder down
Proximal control of the moult is complex and influenced by circannual rhythms of changing photoperiod and temperature. Pineal gland - hypothalamic - pituitary and autonomic nervous system - endocrine pathways seem to operate. Hormonal influences identified include:
'''Proximal''' control of the moult is complex and influenced by circannual rhythms of changing photoperiod and temperature. Pineal gland - hypothalamic - pituitary and autonomic nervous system - endocrine pathways seem to operate. Hormonal influences identified include:
*Oestrogens
*Oestrogens
*Progestogens
*Progestogens
*Prolactin
*Prolactin
Ultimate control of the moult involves many factors, the most influencial being '''nutrition'''.
'''Ultimate''' control of the moult involves many factors, the most influencial being '''nutrition'''.
Feathers can constitute in excess of 10% of the body mass of a bird and renewing this amount of tissue in a relatively short period of time places a high metabolic and nutritional demand on a bird.
Feathers can constitute in excess of 10% of the body mass of a bird and renewing this amount of tissue in a relatively short period of time places a high metabolic and nutritional demand on a bird.
*'''Protein''':
*'''Protein'''
Protein, mainly in the form of ''keratin'' makes up approximately 90% of the dry matter content of feathers. Structurally, keratins contain a higher level of the sulphur-containing amino acids '''methionine''' and '''cysteine''' than normal body or egg protein.
Protein, mainly in the form of ''keratin'' makes up approximately 90% of the dry matter content of feathers. Structurally, keratins contain a higher level of the sulphur-containing amino acids '''methionine''' and '''cysteine''' than normal body or egg protein.
There is no indication that (mal)nutrition has any proximal control over the onset of the moult as moult will proceed irrespective of the nutrtional status of the bird.
There is no indication that (mal)nutrition has any proximal control over the onset of the moult as moult will proceed irrespective of the nutrtional status of the bird.