Deficiency diseases-iodine deficiency, Biology

Iodine  deficiency

Iodine is an important component of thyroid hormones, which play active role in several physiological process such as control of basal metabolic rate, oxidation, protein synthesis, immune and muscle functions.


Aetiology: Deficiency of iodine may be primary due to inadequate dietary intake of iodine or may be secondary to conditioning factors such as high intake of calcium or continuous intake of sub-lethal quantities of cyanogenetic glycosides containing plants or plants of Brassica spp including cabbage, rapeseed, turnips and kale. Diets rich in linseed meal and soybean by- products are also considered to be goitrogenic. Pastures heavily dressed with crude-sewage have been incriminated as a cause of secondary goitre in calves. Calcium rich and humus deficient soils are likely to contain relatively low iodine and may predispose iodine deficiency


Clinical findings:
Deficiency of iodine causes decreased production of thyroxin  and stimulation of thyrotrophic hormones by pituitary gland. This is associated with hyperplasia of thyroid tissue and weakness and hair abnormalities in the affected animals. Signs of loss of libido in males, and failure to express oestrous, abortions and stillbirths in females, and weak new born calves are important signs of iodine deficiency. Affected calves have thick neck and in some cases enlarged thyroid may even obstruct respiration. Alopecia and palpable thyroid gland are found in different species. Alopecia may not be evident in affected foals, but they are too weak to stand and suffer from excessive flexion of the lower forelegs and extension of lower parts of hind limbs. Defective ossification, lameness and deformity of the hock are also evident in foals.


Characteristic signs in pigs include birth of hairless and weak piglets. Most affected piglets die within few hours whereas survivors are lethargic, grow poorly and have abnormal gait due to weakness of legs. Iodine deficiency in adult sheep is marked by thyroid enlargement and increased length of gestation. Newborn lambs are weak and have extensive alopecia and palpable thyroid. Clinical signs in goats are similar to those found in sheep. There is alopecia of varied severity and goitre in kids. Enlarged gland in surviving goitrous animals may extend to greater part of neck causing oedema. Palpation over jugular furrow may reveal presence of a murmur and thrill termed as ‘Thyroid Thrill’.


Diagnosis: Iodine deficiency can be easily diagnosed if goitre is present. Estimation of iodine in blood and milk are reliable laboratory tests. Organic or protein bound iodine in serum or plasma is used as a pointer to circulating thyroxin. Serum thyroxin (T4), and iodine in pasture and bulk tank milk are used to monitor iodine deficiency.


Treatment and Prevention:
Supplementation of iodine in diet at the recommended levels (0.8-1.0 mg per kg DM of feed in lactating cows and 0.1-0.3 mg per kg of DM for pregnant cows) is useful in preventing iodine deficiency. Salts of iodine or mineral mixture can be used to enhance iodine level in diet in iodine deficient areas. Application of tincture of iodine (cattle 4 ml, and 2 ml in pigs and sheep) to inside of flank or parenteral administration of iodine or drenching pregnant ewes with 280 mg potassium iodide or 370 mg potassium iodate during 4th or 5th month of pregnancy are also used for effective prevention of iodine deficiency.  Iodine therapy needs to be instituted with precaution as excess dose may cause toxicity. The minimum toxic levels for calves and pigs are 50 ppm and 400 ppm, respectively.

Posted Date: 9/19/2012 2:23:57 AM | Location : United States







Related Discussions:- Deficiency diseases-iodine deficiency, Assignment Help, Ask Question on Deficiency diseases-iodine deficiency, Get Answer, Expert's Help, Deficiency diseases-iodine deficiency Discussions

Write discussion on Deficiency diseases-iodine deficiency
Your posts are moderated
Related Questions
Is there any situation in which DNA is made based on a RNA template? What is the enzyme included? The process in which DNA is synthesized having as template a RNA chain is know

What are lichens? How do fungi participate in this ecological interaction? Lichens are produced by mutualist ecological interaction among fungi and algae or among fungi and cya

Q. Which is the first (human) heart chamber into which blood enters? Where does the blood go after passing that chamber? What is the name of the valve that separates the compartmen

GOLGI COMPLEX ( GOLGI APPARATUS = GOLGI BODY) The Nobel laureate, Camilla  Golgi (1898)  discovered  the  presence of a special,  small group  of interconnecting  membranous  s

Rapidly Flowing Waters - Biota of Rivers In the rapidly flowing section of the river, the water current is the dominant feature. Everything that is not attached or weighed is

Primary  Tubercle  (Ghon Tubercle): When  an  individual with  no  previous exposure  to  tuberclosis inhale a sufficient number of  tubercle bacilli into the alveoli, tubercu

Prevention of flap dehiscence Flap margin dehiscence (separation) is prevented by approximating the edges of the flap over healthy bone by handling the edges of the flap gently

Briefly explain how amniocentesis and chorionic villi sampling are used in genetic screening. A small sample is removed from the amniotic fluid surrounding the fetus or from t

Toxoplasma gondii Another well known Sporozoan is Toxoplasma gondii which has an unusually wide host- range for n protozoan parasite. It can probably infect all warm-blooded a

Stages of Aerobic Respiration: Glycolysis (cytoplasm) Process 2ATP used for Glucose -> Fructose 1,6 bisphosphate Fructose splits into G3P and DHAP. DHAP