BUSH-SICKNESS.

Rotorua Morning Post, Volume 1, Issue 200, 16 April 1932, Page 6

BUSH-SICKNESS.

(Mr. C. G. Dillon states the case for "Ir on-defic' ency ." ) In the words of Mr. B. C. Aston, chief chemist to the Department of Agriculture, advancing anaemia is the only symptom in bush-sickness. It is considered that iron-deficiency symptoms are unmistakeable and include the anaemia of bush-sickness. That there are const tutional weaknesses in the stock taken on to bush-sick areas is axiomatic from a consideration of the type and value of stock selected. But the references to the analytical work already done will serve to show that bush-sickness is "mainly an iron deficiency." That animals once ;n the very much emaciated state known as bush-sickness are an 'easy host for all kinds of parasites, from bacteria to worms, must also be considered axiomatic. Reference is made1 to N.Z.J.A., Jan. 1928, p 51. Mr B. C. Aston, in 1904, analysed blood of animals suffering from bush-sickness and immed'ately relegated his views of causative agencies to the expression "mainly an iron-deficiency." Both the flesh and blood of sueh animals is deficient in iron. Analyses both of pasture grasses and of so:ls on affected areas show d'eficiencies in iron and available iron respectively. Such animals, if given iron in such a simple form as iron rust, at once recover and the iron content of both blood and flesh approaches the normal. In the 1 ght of these chemical analyses there is orly one conclusion logical and scientific. This is that bush-sickness is mainlv an iron-deficiency disease. For the sake of these analyses it becomes "'ncorrect and unscientific to refer to iron as an "antidote " Iron Successful. All maner of iron compounds give successful results.. Amongst these may be mentioned ferrous sulphate, iron ammonium citrate, and ferrous "arbonate. Bush-sick land treated with basic slag Svhich contams about 17 per cent. of iron calculated as oxide immediately loses that stigma. Farms not so treated and adjoining remain bush-sick. Authorities in other lands are us:ng the New Zealand Department's conclusions and these are confirmed. The same and similar deficiencies occur as "piningdisease" of sheep in the Cheviot district, Scotland, "coasty disease" of Tasmania and "Nakuruit:s," a disease of cattle in Nairobi, British East

Africa. These diseases were predicted, on the basis of gnalyses revealing deficiency in available iron, to be the same as bush-sickness. Treatment by use of iron salt lick confirms the identity or similarity. Reference is made to the January, 1928, issue of the New Zealand Journal of Agriculture. A recent conversations with the officer in charge of the veterinary laboratory, New Plymouth. has disclosed that a similar disease, and analytical finding with iron-deficiency the basis is reported in the United States of America. Authorities in America are using New Zealand's research with 'success. In referring to the article in the "Morning Post's" issue of April 12, it should be noticed that' the Department do not argue a laek of iron in the pasture grasses because of a known lack in the soils. The Department's premises with reference to iron-defi-cieney in the pastures are based on analyses of both pasture clovers and grasses. The N.Z.J.A., Jan, 1928, issue is emphatic in its statements of deficiency of iron in red clover Other issues of the journal bear record of deficiencies of iron in coeksfoot, white clover, rye, etc Conclusions of the Department were recently published which are in refutation of the assertion that premises for pasture grass deficiencies are taken from soil analyses, but it does inde'ed appear true that the Department were hasty in arguing an indigestible iron in pasture grasses because the iron was in the soils in a form unavailable for ass'milation by stock.

Periodic, Not Epidemic. The findings of both the Agricultural Department and private research are opposed to the "epidemic" nature of the disease. A far better adjective is the "periodicity" of the d;sease. Well known to soil-analyists and agriculturalists al:ke . is the definite periodicity or period'c variation of certain soil minerals from season to season and year to year. This periodicity is in direct relation to climatic conditions. Observed are heat and light intensity, rainfall and atmospheric pressure. These factors, together with . the favouring of some plants and intolerance towards others in certain decades, make for vast changes in the mineral content of the soil. It is known that calcium, phosphorus and iodine are amongst those minerals which are attended by this periodic1 ty. These minerals are present in most pastures in greatest quantity in spring and the fall in soil content is very much appreciated until the end of winter. The writer has not read with suffic'ent extent to declare the inclusion of iron in this periodicity. But here is a theory which, tentatively. gives adequate explanation of the periodic nature of bush-sickness. If there is a m'neral or minerals capable of sustaining animals suffering from ironstarvation and if there is a sudden drain-of such support from the soil, it is logical fo suppose that the acute form of bush-sickness attended by extreme emaciat'on and death will result. For consideration of this theory it must be borne in mind that most of the minerals necessary for stock are essential and present, often in only fractions of 1 per cent. by weight of the soil. The bearing of "mineral correlat:on with the indigestible and woody nature of most pastures in certain seasons and the marked absence of any pathological condition to be associated with the disease is, by the writer, considered of paramount importance. The disease is neith'er infectious nor contagious. Horse Not Comparable. Another factor which may throw much light on the periodic nature of the disease is the constitution of the stock present from season to season and, more particularly, from year to year. The horse is sa'd to be immune from bush-sickness. These animals, relative to cattle, are not brad on bush-sick areas and obviously from their earl'er years already have sulficient iron in flesh and blood. How great a drain is laid on milch cows compared with horses- Pigs, being fed on all classes of food, are beyond consideration. Horses, particularly farm horses, frequently are given bran and it is known that cattle given a few handfuls -of bran each week are immune from bush-sickness. Modern physiology is not in a position to declare the fundamental differences be- ' tween the v'tal processes in cattle and horses. Few scientists only. doubt that there are differences. The writer finds difficulty in appreciating comparisons with Mamaku and related areas and the gum lands of North Auckland. In a recent and personal survey the conclusion was reached that the gum-lands contain a conglomerate of all minerals required by stock. Frequently a white mass of iron-deficient clay is found side by side with exactly the same "iron-full" clay found throughout the Waikato. Hills of iron-full clay occur on most farms visited and it was in consideration of the iron in gum-land clays which caused the wr'ter much thought concerning the possibility of exchan?ing this clay for Mamaku pumice (very desirable on the gum-lands) using relief -workers for labour. Department Supported. Experience of improvement with age has been found only in d'rect relation to the amount of slag used as fertiliser. The N.Z.J.A. says "lambs sicken in a we'ek" Research workers of all competency and incompetency are at present engaged in a consideration of bush-sick-ness The Department of Agriculture have indeed declared the iron-defici-ency as causat've. But, since pathological investigation has proved so barren and there ara such great fields open for research in analysis and minerals in relation to stock, the writer is satisfied that mineral-defi-ciency is the one cons:deration worthy of practical interest in bush-sickness, a disease he and many others consid cr successfully diagnosed and combatt^d 28 years ago by the Agricultural Department. Because all manner of conflicting report is extant conearning the value of the Rotorua farm 'lands on account of proxim'ty to Mamaku and other bush-sick areas, the writer wishes lo addend an extract from the N.Z. Journal of agriculture, Aug., 1927. This contains data of a reeonnaissance survey of pumice lands. "Tron starvation" is not known to occur in soils finer in texture than .1 sandy silt and in the fine silt between Atiamuri and Reporoa roads is a silt finer than a sandy silt." This area

comprising part of the southern half of Rotorua county the Department finds is deficient in calcium and phosphorus, but that there is no bone-> malnutrition and bush-sickness is unknown. The Department confesses that the situation is anomalous and writes. "Clovers thrive amazingly, and "The health of stock is remarkables and "These soils may be regarded as the healthiest in the country" and "Their water-carrying capacity is high."