Farm animals, iodine

Without iodine supplements in the form of marine fishmeal or mineral mixtures, the farm animals of most countries worldwide would suffer of iodine deficiency. Germany and most industrially developed countries unconsciously supply farm animals (and in turn the population) with iodine by fertilizing the land with Chile saltpeter, which has a high iodine content. During World War I, the importation of Chile saltpeter to Europe was stopped, and thereafter synthetic nitrogen containing no iodine was produced worldwide. Consequently, iodine deficiencies in both animals and man reap-... 

The supply of 10 mg I kg in the mineral mixtures of farm animals increased the iodine content of the thyroid gland, milk and eggs significantly, but did not greatly affect the iodine concentration of meat and liver (Anke et al. 1989b, c, Wenk and Heinrich 1989). 

Tab. 9.4-10 Limit values for sufficient iodine levels of several tissues and organs of farm animals ( ig kg dry matter) (Groppel 1986)...

Table 9.4-25). The consumption of 200 jg I kg feed DM by growing animals and of 300 xg kg feed DM by milking and egg-laying species met the iodine requirement of farm animals (Anke 1982). The total iodine content of blood serum under these conditions reached the limits of a normal iodine status of farm ruminants (Table 9.4-25). 

The extraction of iodine amino acids from the blood serum (butanol-extractable iodine, BEI) showed that approximately 85% of the FBI consisted of iodine amino acids. Total iodine, FBI and BEI in the serum of farm animals was correlated (r = 0.83 and r = 0.89, respectively) (Groppel 1986). However, no correlation was observed between the total serum iodine content and T4 correlated with r = 0.66. 

Species differ widely in their susceptibility to iodine toxicity, but all species can tolerate iodine levels far in excess of their normative requirement. The main problem of iodine intoxication in farm animals is not poisoning but the iodine overload of humans through milk, dairy products and eggs (Anke et al. 1994, Burkhard et al. 2002). 

The use of iodized salt in the manufacturing of processed foods and mineral mixtures for farm animals met the iodine requirement of humans (Harris et al. 2003, Jooste et al. 2001, Oberhofen 2003, Ivarson 1973, Iwarson and Ekman 1976, Stibi and Hole-man 2002, Scriba et al. 1975, Meng and Scriba 2002, Hampel et al. 2000, 2001, Gartner et al. 2001). 

In 1985, to combat iodine deficiency in the former state of East Germany, salt for human consumption was iodized and iodine was added to animal feed (Anke et al., 1993). Eliminating iodine deficiency in farm animals improved the iodine content of milk and eggs. This further increased the dietary iodine intake of East Germans (see section The Effect of Iodine Intake on the Iodine Gontent of Eggs, Meat and Milk ). The program successfully reduced iodine deficiency in both humans and farm animals, and could be used as a model for iodine supplementation in other countries. 

The recommended dietary iodine intakes represent amounts of iodine sufficient to prevent symptoms of deficiency and impairment of health or performance while maintaining the body s store of iodine (see sections Requirements/ Recommendations for Iodine Supplementation and Response Criteria and Dose—Response Studies of Iodine Requirement in Farm Animals ). Recommended daily... 

Despite the low iodine content of plants, the development or severity of iodine deficiency is amefiorated by the trace amounts of iodine in some feeds, drinking water and even air. As a result of the iodine content of seawater and its vaporization and precipitation air, water, soil and plants in coastal regions contain more iodine (McDowell, 2003). Livestock kept on coastal farms are therefore less at risk of iodine deficiency than those reared on mountains. In addition, the types and amounts of iodine antagonists, the iodine reserves and salvaging mechanisms vary between farm animal species, categories, herds and individuals. 

Iodine feed supplements must be stable to meet the needs of several groups of farm animals. lodates [Ca(I03)2 X 6H2O Ca(I03)2] and iodides [Nal KI] are both approved feed supplements in the EU (2003, 2005). lodates are more stable than iodides as feed additives and so are used preferentially. Cheeke (1991) suggests that eth-ylenediamine dihydroiodide (EDDI) and pentacalcium orthoperiodate may be suitable feed iodine additives, but does not include information on their stability. In our studies we found that a casein-bound iodine supplement produced by milling casein with KI was highly stable Schone et al., 1997c). 

Response criteria and dose-response studies of iodine requirement in farm animals... 

Although farm animals can adapt to diets poor in iodine, the prevention of deficiency requires the use of simple and valid laboratory criteria to diagnose iodine deficiency. As stated above, the thyroid iodine content of hypothyroid animals with goiter is low. As a result levels ofT4 in the serum are undetectable, but reduction of T3, the more active thyroid hormone, only occurs if iodine deficiency is severe. Elevation ofT3 may occur in early hypothyroidism however, this is not consistent and can not therefore be used to diagnose iodine deficiency (Schone et al, 1991). 

Effects of Excessively High Dietary Iodine Intake on Farm Animals and Poultry... 

There are relatively few investigations of thyroid iodine concentrations in farm animals and poultry fed a broad range of doses of iodine. However, the response to iodine supplementation seems to vary with age and between species. 

This chapter describes some dose-response studies of the iodine requirement of farm animals fed typical grain diets without or with glucosinolates as iodine antagonists. 

The iodine content of eggs, milk, and to some extent meat, produced by farm animals reflect the feed iodine supplementation. The effects of increasing iodine intake... 

Traditional use Root decoctions and root tinctures, sometimes mixed with tinctures of iodine and St. John s wort (Hypericum), are used to treat scabies in humans (Ogolevitz 1951). A decoction of the roots is used to disinfect the mouth and to kill ticks, fleas, and bed bugs on farm animals. The roots are put on hot ashes and after 2-3 h are then put on surface wounds. The above and underground parts are used in a bath to treat skin diseases (scabies, fungal, etc.). A decoction of the aboveground parts is used as a mouth wash to treat toothaches (Khodzhimatov 1989). 

---