Foals of mares that were fed excessive amounts of iodine during pregnancy often are affected by hypothyroidism. The clinical signs in foals include dyspnea, weakness, ataxia, and goiter, failure to suckle, silky and long body hair, collapse of the bones, sudden death and still birth. Diagnosis of hypothyroidism is made through the clinical signs and symptoms, serology showing a decrease in the circulating levels of T3 and T4 and TSH stimulation test.
Treatment includes
replacement therapy using daily oral synthetic thyroxine.
Hyperthyroidism
Hyperthyroidism indicates that there is an increase in the production and secretion of thyroid hormones.
Hyperthyroidism is
though it may be related to high dietary intake of iodine in
adults.
The increased circulating levels of T3 and T4 cause a systemic increase in cellular metabolism, oxygen and nutrient usage, and cell waste production.
and Arabians are predisposed to hyperthyroidism.
The clinical presentation of hyperthyroidism includes weight loss, , polyphagia, polydipsia, pollyuria, goiter, increased fecal output, sweating, hyperthermia, tachycardia and tachypnea. Diagnosis is made through serology showing an increase in the circulating concentration of T3 and T4. Treatment includes the administration of anti-thyroid medications such as methimazole or the administration of radoiodine.
Anhydrosis
Anhydrosis is the inability to
in response to normal stimuli.
Anhydrosis is idiopathic though it is thought to be related to dysfunction of the or to the desensitization of the receptors found on the sweat glands.
,
The most common reasons for dysfunction of the sweat glands are the obstruction of the sweat ducts or the autoimmune degradation of the sweat glands. Sweat gland receptor desensitization occurs when the horse is in a stressful situation or is under environmental stress for a period of time. This causes prolonged exposure of the sweat gland receptors to high circulating levels of causing the down regulation of the sweat response to heat or stress.
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