SALT AS A STOCK FOOD.

King Country Chronicle, Volume V, Issue 407, 25 October 1911, Page 3

SALT AS A STOCK FOOD.

(By B. C. Aston, F.1.C., F.O S.)

An article appeared in a recent issue of the New Zealand Farmer which put forward the opinion of the author —a practical man—as to the great value to be derived from providing cattle ami sheep with salt as a recognised constituent of their food ration. To endorse and supplement that recommendation with a little technical information is the aim of the present article.

One of the earliest experiments in the use of salt is that of Boussingault, quoted by Leibig ("Letters on Chemistry''). Boussingault experimented with six oxen, three of which had salt and three had no salt. In the course of the second month the difference in the tw ; o lots was visible even to the unpractised eye. The hair en the oxen which had salt was smooth and shiny, and on the other lot it was dull and erect. After a year the signs were still more prominent. On those which had no salt the hair was matted and the skin in places was devoid of hair. Those which had salt, on the contrary, retained the look of stall-fed beasts. Their briskness and frequent indication of a desire to leap contrasted strongly with the heavy gait and cold temperament observed in those which had no salt. It will be observed that these were stall-fed beasts, and that their diet at times may have included a food such as mangels, which may not require the addition of salt, as this plant often takes up a large amount of salt from the soil.

The natural food of any animal as a rule contains sufficient inorganic (mineral) food for its healthy development, with the exception that in the case of ruminants, and indeed nearly all races of vegetable feeders, the addition of common salt (osdium-chlo-ride) is necessary. Now, sodium salts, including the chloride, are present in a'l plants, so that it is evidently not so much a matter of the mere presence as of the quantity which must be present in the food to ensure a perfect ration.

G. von Bunge (quoted by Abderhalden, "Physiological Chemistry") has investigated the macter with great thoroughness, and has elucidated the following facts: that only the herbivora, and never the carnivora, crave for salt; that the food of the herbivora contains an amount of potash three or four times greater than that of the carnivora; and that all vegetables, especially potatoes, clover, and grasses, contain large amounts of potash. Bunge suggests that an excess of sodium salt is necessary to eliminate the potassium salts from the animal system, and in support of his theory states that all vegetablefeeding races of man have such a craving for salt that it is considered one of the necessities of their existence; but in countries where the inhabitants live on meat an rice there is no craving for salt—rice, though a vegetable, containing only one-sixth as much potash as wheat, rye, barely, and Indian corn; one-twentieth as much as legumes; one-twentietn to one-thirtieth as much as potatoes. Races of men which may live on a meat diet alone, such a3 hunters, fishermen, and nomads, have no craving for salt. New Zealand for the greater part is swept by salt sea winds, and possibly for "this reason it has been found unnecessary in many parts to give animals a salt lick. Animals would, howpver, do better with more salt than is supplied in the natural pasture, especially in the inland situations which are shielded from the sea winds by ranges of mountains. Animals fed on mangels, winch contain morn sodium than potassium, need no salt lick, but the reverse is the case with animals fed on turnips, which contain much more potassium than sodium. A word of caution must be said in reference to pigs. An excess of salt is highly injurious to these animals, andit is therefore best not to give them any except that existing naturally in their food. A plentiful supply of common salt (sodium-chloride) is a necessary ingredient in the food ration of all ruminating animals if it is desired to maintain them in the best condition; and if the salt is not present in sufficient amounts in the natural food it must be supplied as a lick in the form of rock or coarse salt.