USE OF IODINE.

Press, Volume LXVI, Issue 20085, 14 November 1930, Page 12

USE OF IODINE.

VALUE IN STOCK • NUTRITION. j i POPULAR THEORY DISPROVED. ; _ Displayed within the Lincoln College 1 information bureau at the A: and P. Association's Show are the results of one of the most important pieces of research yet conducted by the College: The effect of feeding iodine to stock. Scottish agricultural authorities have recommended its use in salt-licks, but the Lincoln College authorities claim that, while the amount of iodine in a salt lick does the sheep no harm, it does the animal no good except in districts remarkably deficient in iodine, while it costs the farmer money. , Results Summarised. Altogether the experiment with iodine at Lincoln is as comprehensive as any yet prosecuted in the world and its results may be far-reaching. They may be summarised thus: — (1) The value of iodine is overestimated. (2) Large quantities retard the growth of the animal. (3) Small quantities are of doubted value, and though it may be used with in goitrous areas, all New Zealand stock does not need it. Little Nutritive Value. Research workers at the Co.llege who were responsible for these experiments in animal nutrition said yesterday that', with all the' patent stock licks on the market, the farmer was in a quandary as to which to buy or whether to buy any at all. Most of them contained a small quantity of iodine and farmers were asked to buy them on the grounds that this chemical made sheep thrive. It was now time to say that iodine had very little value in stock nutrition. Flocks pastured on the, poor soils of Canterbury—with the fourth lowest iodine content of any in New Zealand—which were given iodine showed no improvement over those which had none. Both were grazed in the same paddock. At birth the weight and percentages"t>f lambs from each flock were equal, while the lambs of the iodine-dosed ewes wore two pounds lighter in weight than those of the ewes which had had none. It was shown that the recommendations of the Scottish agricultural authorities were based on experiments carried out on one or two sheep. For the Lincoln College trials there were eighty sheep in each floek and the tests had been carried out for nearly a year. Thuß there was no "hit or miss" system about it. Advice to Partners. There was no suggestion, Lincoln College investigators said, that iodine was not useful where goitre in animals was' prevalent, but as an aid to nutrition in ordinary cases it was practically valueless. . _ The r information they explained, was much in season at a time when farmers were being urged io use all kinds of salt licks because of their iodine content, and were also being advised to use different chemicals for their stock. If this were. borne in mind they, could assess the - value of sniel} preparations for themselves but, in many case#, an ani-, mal needed no greater supply of. iodine and many other chemicals thin : was' to. be found in succulent grass.