Changes

There are various hormones that may infulence the structure of the skin.  These influences may be made apparent by the repeated long-term administration of various glucocorticoids or their analogues.  Endogenous imbalances are generally seen in adult mature animals although congenital forms have been seen, especially with [[Endocrine System - Thyroid Gland - Anatomy & Physiology#Problems associated with the Thyroid Gland|hypothyroidism]].  The hormones implicated as important for maintaining skin structure are '''thyroxine, cortisol''' and '''estradiol'''.  Deficiencies or excessive production may result from abberations in the function of the [[Endocrine System - Adrenal Glands - Anatomy & Physiology|hypothalamic-adrenal axis]],  the '''adrenal gland, thyroid gland''' and the '''gonads'''.

There are various hormones that may infulence the structure of the skin.  These influences may be made apparent by the repeated long-term administration of various glucocorticoids or their analogues.  Endogenous imbalances are generally seen in adult mature animals although congenital forms have been seen, especially with [[Endocrine System - Thyroid Gland - Anatomy & Physiology#Problems associated with the Thyroid Gland|hypothyroidism]].  The hormones implicated as important for maintaining skin structure are '''thyroxine, cortisol''' and '''estradiol'''.  Deficiencies or excessive production may result from abberations in the function of the [[Endocrine System - Adrenal Glands - Anatomy & Physiology|hypothalamic-adrenal axis]],  the '''adrenal gland, thyroid gland''' and the '''gonads'''.

Cutaneous changes may include [[Anatomy & Physiology of the Hair#Hair Types|telogen]] hair follicles leading to [[Skin - glossary|alopecia]], epidermal and dermal thinning, atrophy of [[Anatomy & Physiology of the Skin#Glands|sebaceous glands]] and the [[Anatomy & Physiology of the Hair|arrector pili]] muscles.  There may also be an increased risk of microbial infection due to poor immune surveillance and delayed wound healing.  There are significant differences between species in the manifestation of symptoms.

Cutaneous changes may include [[Anatomy & Physiology of the Hair#Hair Types|telogen]] hair follicles leading to [[Skin Glossary - Pathology|alopecia]], epidermal and dermal thinning, atrophy of [[Anatomy & Physiology of the Skin#Glands|sebaceous glands]] and the [[Anatomy & Physiology of the Hair|arrector pili]] muscles.  There may also be an increased risk of microbial infection due to poor immune surveillance and delayed wound healing.  There are significant differences between species in the manifestation of symptoms.

==Nutrition and the Skin==

==Nutrition and the Skin==

Trace elements such as '''copper''' are rarely deficient in farm animals, although deficiency can be associated with poor fertility, ill-thrift and leukotrichia - leading to perioccular 'spectacles'.  This reflects the role of copper in the formation of [[Skin - Anatomy & Physiology#Cells of the Epidermis|melanin]].

Trace elements such as '''copper''' are rarely deficient in farm animals, although deficiency can be associated with poor fertility, ill-thrift and leukotrichia - leading to perioccular 'spectacles'.  This reflects the role of copper in the formation of [[Skin - Anatomy & Physiology#Cells of the Epidermis|melanin]].

Excessive exposure to trace elements can also have harmful effects and again, although rare, examples may include '''selenosis''' which is usually seen as [[Skin - glossary|alopecia]] in geographical areas with high '''selenium''' soil content for grazing animals.

Excessive exposure to trace elements can also have harmful effects and again, although rare, examples may include '''selenosis''' which is usually seen as [[Skin Glossary - Pathology|alopecia]] in geographical areas with high '''selenium''' soil content for grazing animals.

===Vitamins===

===Vitamins===