FEEDING VALUE OF IODINE.

Otago Witness, Issue 3802, 25 January 1927, Page 12

FEEDING VALUE OF IODINE.

Directly or indirectly all life is de pendent upon plants. The . herbivorous animals or farm stock depend upon the green food, and, if other animals require flesh, this same flesh has been produced from materials stored up by plants. Consequently it will be granted. that farming resolves itself into the growing of plants. These plants, like animals, require food, and in some manner must be fed in order to ensure healthy stock. In the soil, of course, there are many elements other than those essential to plant life, and, in the case of those minerals which supply the needs of average plants, it is well to realise that it is only in the soluble state that they can enter the roots qf plants. One must remember that the plant food, in the soil exists in two forms—it may be available or r»on-available—and the growth of the plant depends upon the amount of

available food. The so-called available food is continually being made available (though often very slowly) through the weathering action of frost, water, cultivation, and other agents, but the call of grazing country is also constant, and very heavy. Healthy stock life ensures a continual call upon those chemical substances which go to make healthy plant life. “The significance of iodine in animal nutrition appears to be important,’’ says the principal of - the Staffordshire Farm Institute, in replying to a New Zealand stock breeder’s inquiry about pig feeding. The reply has been issued in brochure form, and, in part, reads as follows: —“Mineral salts have been used in our herd of pedigree Large White pigs for over three years with good results. Some of our pigs have been inbred somewhat closely, but in the past three years they have been practically free from rickets, and their general health has been excellent, and the mortality low. Previous to the use of the mineral salts the herd contained a fairly large percentage of pigs suffering from coughs. This disease has now been almost eliminated.

“In an experiment carried out at the end of 1922, we found that the addition of mineral salts resulted in an increased average daily gain of 2oz per pig. “Besides being a known prophylactic against goitrous conditions, iodine, according to recent scientific evidence from U.S.A., has an important bearing on fecundity. We made an attempt at the Farm Institute to test this point last year,'~imd, although our conclusions were not very definite, we thought that gilts fed from an earlyage with complete minerals, produced larger litters than sister gilts which had mineral salts, but no iodine. “The value of the mineral salts was proved in an experiment carried out at the Farm Institute in 1923. All the ingredients in the mixture, except the iodide of potash, are relatively cheap. The amount of iodine in the salts is so small that pig keepers have questioned whether it was worth while including it at all. Several authorities considei’ iodine to be a vital factor in the nutrition of pigs, particularly those carrying young, la an attempt to determine the value of iodine for breeding pigs, an experiment was commenced at the Farm Institute in September, 1924. Nine' three-months-old pedigree Large White gilts were' selected foe the experiment. In point of age the gilts were nearly the same, and in point of breeding, they were identical, all nine being sired by the same boar out. of three litter-sister sows.’’

Farrowing was earliest with the gilts receiving complete minerals, and the number of pigs was much greater than from those receiving no-minerals, while, in respect to size, the pigs receiving no minerals did better than those to which incomplete minerals were fed. bearing out the opinion held in some quarters that increase in the supply of calcium (lime) without a corresponding increase of iodine has a detrimental effect in nutrition. The mineral salts used were at the rate of per head per day (11b per month), and compressed, steamed bone flour, 151 b; carbonate of lime, 201 b; flowers of sulphur, 151 b; wood ashes, 151 b; common salt, 351 b ; iodide of potash, soz. Recent literature on this subject indicates the very great importance of iodine in districts where the wtaer is deficient in this element, and the necessity of ensuring that stock have adequate supplies of the essentials of health. —