AGRICULTURAL RESEARCH

Dominion, Volume 21, Issue 110, 7 February 1928, Page 13

AGRICULTURAL RESEARCH

ACHIEVEMENTS IN THE DOMINION

INVESTIGATION OF “BUSH

SICKNESS”

DISCOVERIES OF EMPIRE-WIDE VALUE

In recent years a considerable amount of agricultural research has been carried out by chemists and other experts of the Department of Agriculture, yielding results which are increasing the wealth of the country. Under the scheme for co-operation and co-ordination of research work organised by the Department of Industrial and Scientific Research, the Dominion is considered certain to take a very prominent place in the future development cf agricultural research within the Empire. Great Britain is the world’s largest importer of agricultural products. The annual value of her imports is about £484,000,000, of which some £177,000,000 comes from British Dominions and dependencies. Agricultural research is of special interest to New Zealand, because Great Britain receives 85 per cent, of the total agricultural products exported from the Dominion.

One of a recent series of articles on "Agricultural Research in the British Empire” in the “Scottish .Toitrnal of Agriculture,” is devoted to New. Zealand, and covers the work done in respect of wheat breeding, control of noxious weeds, fruit growing, and malnutrition in stock. Empire Agricultural Research. “In view of the attempts being made at the present time to secure co-opera-tion in research within the Empire,” the writer says, “it is of special interest to note that all the main lines of research being carried out in New Zealand have a dicept bearing on problems in other parts of the Empire. Thus the problems of mineral deficiencies in the pasture are of the same nature as those occurring in South Africa and Canada, and the work on these problems in New Zealand is throwing light upon similar problems elsewhere. Aston’s work on ‘bush-sickness’ has proved of value in connection with a somewhat similar disease occurring in limited areas in Kenya Colony and in tho South of Scotland. In the same way the work on ‘biological control’ of injurious insects and noxious weeds is of general Empire interest. Indeed, some of the work referred to above has already been applied successfully in Australia. “In recognition of the value to the whole Empire of the work in New Zealand on deficiencies in the soil and pastures, a special grant has been made by the Empire Marketing Board Research Committee for an extension of the work now proceeding on the mineral content of pastures. This extended work is to be carried out as part of a general scheme which connects up the work on mineral metabolism at the Rowett Institute, phosphorus deficiency, in South Africa, mineral deficiencies in pastures in East Africa, and indeed all important work of this nature throughout the Empire. Malnutrition in Stock. “Though New Zealand is in many ways such au excellent stock country, deficiency diseases occur in some districts. A disease in tho bones was noticed some time ago amongst sheep which had been moved from one pasture to another. They ceased to thrive, and when made to walk they were seen to be lame. Fractures of the bones were frequent. Post-mortem examination sl-.owed that in well-marked cases the bones had become thin and shell-like. An investigation into the cause of this condition revealed tho fact that tho land on which this condition occurred was deficient in lime and phosphorus. The appropriate measures have been taken to prevent this disease in sheep. It is still, however, prevalent among cattle, especially in heavy milking cows. These are treated by the administration of substances deficient in the pastures, but there is urgent need for further work in determining tho nature of tho deficiencies in tho various pastures and fodder

plants. ‘Bush Sickness' Research. “A specially interesting case of deficiency disease, known •as ‘bush-sick-ness,’ occurred in a district in the North Island. The researches of Mr. B. C. Aston, head of the Chemical Division of the Department of Agriculture, Lave established the nature of this disease, and, what is more important, a. successful method of treatment. The chief symptoms are extreme anaemia and emaciation. The administration of iron salts leads to a cure.” Further interesting references to the research work of Mr. Aston were made in a paper on animal husbandry read at the Imperial Agricultural Research Conference Jicld in England in October, at which New Zealand was represented by Dr. 0. J. Reakes, DirectorGeneral of Agriculture. A memorandum regarding iron starvation in ruminants —that so-called “bush sickness”—stated : “This is a deficiency disease, proved to bo non-transmissable, and one that does not spread, occurring in ruminant stock only, when pastured on land extending over a wide area in the central volconic plateau of the North Island of New Zealand, and the adjacent country. Some millions of acres are more or less affected, the soil being formed from rhyolitic pumice deposited from air, not water, as is usual-

ly the case in the formation of soils. "In 11)01. an analysis of Mr. B. C. Aston of the blood of an animal in an advanced stage of the disease showed that there was a great deficiency of iron, which led him to suggest Ihe trial of ferrous sulphate as a topdressing for pasture upon which sheep were grazed in an experimental paddock. When the results were obtained, it led him to suggest that a deficiency of iron in the pasture (the animal’s sole ration) was the cause of the disease. After some

twenty years’ laboratory and field work, it is considered fully proved that bush sickness is really iron starvation. Animals in an advanced stage of the disease are fully restored to health on the same feed as that upon which they became affected if dosed with phosphate of iron in the form of Syr. Ferri. Phos. Co. B.P. or with the double citrate of iron ami ammonium. If the animal is not so dosed, it invariably dies, and if dosed, it just as invariably recovers, all the symptoms being those of nutritional anaemia. It is important to remember that if steps aie not taken to prevent the disease in a herd, the mortality will be 100 per cent., whereas a non-ruminant, e.g. horses, may continue healthy for many years on the same food and water on which a cow will sicken and die in from six to nine months. . . "The pasture is composed chiefly of red and white clovers and cocksfoot. Animals taken away for a change to healthy country, and then brought back still in poor store condition, may now bo fattened on the pasture upon which they originally became sick. The bones of an anima”! dead of bush sickness show no signs of malnutrition. Hit, facts indicate .that the disease cannot bo referred to chronic poisoning, and that a deficiency in some essentia! element in tbo food is the real cause. I lie abundance of clovers, and the excellence of the diseased animal’s bones, preclude the thought that the bone-forming elements, calcium and phosphorus, are deficient in the pasture. heeding tests have eliminated all other essential elements except iron, which is found to be abnormally low in the affected sods, and in the pasture grown upon them."