INVESTIGATION PLANNED

Press, Volume LXXIV, Issue 22435, 23 June 1938, Page 9

INVESTIGATION PLANNED

RESEARCH INTO ALL ASPECTS “MOST COMPREHENSIVE EVER CARRIED OUT” DEPARTMENT’S . PROGRAMME ANNOUNCED [THE PRESS Special Service.! WELLINGTON, June 22. “The most comprehensive single investigation ever carried out in New Zealand into livestock diseases has been nlanned by the Department of Agriculture for the recent outbreak of facial eczema,” said the Minister for Agriculture the Hon. W. Lee Martin, in a statement to-day “The bulk of the work will be carried out at the Ruakura experimental farm, near Hamilton; but researches, will also be undertaken at the Wallaceville veterinary laboratory, and the grasslands division of the plant research bureau. The offlcer-in-charge of the investigation is Mr J. F. Filmer, veterinary research officer of the Department of Agriculture.” The programme was outlined to-day by the Minister at the opening of the Rotorua Show. “Immediately facial eczema became prevalent in the Waikato, the department enlarged its veterinary staff in the Waikato, and by personal instruction, newspaper announcements, and radio broadcasts disseminated information on the treatment and preventive measures,” said the Minister. “In cooperation with the farmers of the district, committees were set up to act as liaison organisations between the departmental officers and the farming community, and arrangements were made for the collection of data on the circumstances of the outbreak. Pathological and bio-chemical examinations of material from animals killed at various stages of the disease were carried out at Wallaceville. and chemical examinations of the pastures were made by members of the staff of the chemistry section of the Department of Agriculture. A number of suggested remedies brought under the notice of farmers were tested: but none of these gave beneficial or even encouraging results. The only treatments which proved of value were those based on previous experiences and investigations carried out by departmental officers. These included the shifting of stock off flush pastures, the drenching of affected animals, the protection of lesions on the skin from the direct rays of the sun, and the feeding of hay and silage in place of young green herbage. This procedure was advised by the department in February last. Full Staff Engaged “In other districts, also, the services were strengthened, and in addition to the eight veterinarians in the Waikato district, two more at Wallaceville were deputed to give their whole attention to the work, and seven more were engaged full-time on facial eczema in the Wairarapa, Taranaki. Hawke’s Bay. North Auckland, and Manawatu districts. In addition, the specialist staff on the outbreak included three chemists, a bio-chemist, five officers of the Fields Division of the Department of Agriculture, and officers of the Department of Scientific and Industrial Research.

“At this stage practically, the whole of the activities of the officers were confined to coping with the serious state of emergency which had arisen; but the necessity for a long-term programme of investigation was also realised. , . . “For the purpose of planning this investigation, a committee of management was set up consisting of Mr J. F. Filmer (chairman), Dr. Annett, Messrs Hayward and Anderson (farmers’ representatives), P. W. Smallfleld (Fields Division, Department of Agriculture), R. E. R. Grimmett (Chief Chemist. Department' of Agriculture), and E. B. Levy (Director of the Grasslands Division of the Plant Research Bureau). The committee is to direct the investigation which, it is estimated, will cost about £IO.OOO. The research work may be broadly classified under three headings. “(1) An extensive survey by veterinary and field officers of the department in the affected areas of the south Auckland district, to obtain all possible information about the outbreak.

“(2) Intensive field and laboratory work at Ruakura by veterinarians and chemists, with supplementary work at Palmerston North. "(3) Pathological work at the Wallaceville veterinary laboratory. Questionnaire Sent Out “The programme has already commenced. A questionnaire was prepared by the Livestock and Fields Divisions of the Department of Agriculture, and by a personal canvass of affected and non-affected farms, made by departmental officers, information on the following aspects of the outbreak has been collected:—Area of farm topography and nature of soil, composition of pasture, top-dressing, grazing practice, incidence of disease in cattle and sheep, condition of pasture when disease occurred, supplementary feeding or special grazing after rain, numbers of various classes of stock on the farm, butter-fat production, and meteorological data. The replies to these questions are now being sifted and tabulated under Mr Filmer. “A trial to determine whether concentrate feeding will assist sheep affected through the > winter has been commenced at Ruakura. A study has also been madb of the salient facts of the investigation in South Africa of geeldikkop, a disease similar to, if not identical with, facial eczema, and work along the lines of the South African experiments has been commenced in New Zealand at Wallaceville and by the chemistry section of the Department of Agriculture. South Africa, it may be mentioned, lost 500.000 sheep through this disease in 1928,

South African Experiments “In South Africa experiments were designed whereby skin lesions were produced by surgical obliteration of the common bile duct. It was, then found that phyloerythrin, a compound closely allied to chlorophyll, accumulated in the bile, and also in the blood. By injection of this substance, it was found possible to produce skin lesions in healthy sheep when these were exposed to sunlight. Further investigations showed that the production of phyloerythrin in the elementary tract of ruminants is a normal process. Apparently the chlorophyll is converted into this substance by the activity of bacteria, mainly in the rumen. “In normal animals, phyloerythrin never reaches a sufficient concentration in the blood to render the animal sensitive to light, but when any interference with the secretion of bile takes place a dangerous concentration of phyloerythrin occurs in the blood, and if the animals are exposed to sunlight, skin lesions occur. On account of the

irregular results obtained from tribulus, attention has recently been directed to a species of lyppia, a plant which constantly produced the liver condition characteristic of both geeldikkop and facial eczema, although this plant is not in any way concerned with the production of the former disease in the field. “If the animal has been on a diet containing chlorophyll, and is exposed to light, skin lesions also supervene, but if the animal has been kept on a diet free from chlorophyll, no skin lesions are observed. “In 1937 the active principle which causes the liver condition was extracted from lyppia, and it has been named by the South African workers ‘icterogenin.’ This substance, when fed to sheep, produces the same liver condition as the plant itself, and again the presence or absence of skin lesions is determined by the chlorophyll content of the diet. As facial eczema so closely resembles geeldikkop, it seems probable, though by no means certain, that its etiology will prove similar and investigations towards this end have been commenced in New Zealand. “A full programme of chemical work drawn up by Mr Grimmett has been adopted by the committee of management. This investigation embraces three fields—animal tissues, pastures, and soils. The work on animal tissues, such as the chemical changes in bldod, bile, liver, etc., or the presence of unusual metabolic substances, will be undertaken by Mr S. W. Josland, of the Wallaceville laboratory, in collaboration with Mr Filmer, and they will have the resources of the chemistry section of the Department of Agriculture at their disposal. Pasture Work “The pasture work will include immediate investigations into the composition of pastures on which facial eczema is occurring, and a comparison with unaffected pastures. This is particularly concerned with the search for plant metabolites of unusual nature, or present in unusual amounts, such as icterogenic substances, toxic amino acids, or amides, chlorophyll, carotene, and other plant pigments, etc. Large quantities of grass have been collected for these studies, and some data is already available; but no more material from the affected pastures can be obtained this season. “Dr. F. B. Shorland and Mr N. T. Clare, of the qhemistry section, are working on these materials, and the activity of any metabolites separated is' being tested at Wallaceville. Longterm investigations of the mineral and organic constituents of pastures have also been planned. “Mr R. E. R. Grimmett reported that large quantities of non-protein nitrogen were found in some of the flush autumn growth by Dr. Shorland and Mr Clare, and quantitative studies of the relative percentages of protein and non-protein nitrogen bodies are to be carried out on a general survey scale throughout the year on typical affected and non-affected pastures in continuation of the data already accumulated. Similar studies will also be carried out by officers of the Department of Scientific and Industrial Research at Palmerston North. “The study of the fibre constituents of pastures (lignin, cellulose, hemicelluloses), pectins, sugars, and other carbohydrates will be undertaken at both Ruakura and Palmerston North by Dr. R. J. Mcllroy, who has specialised in this work, taking his doctorate on the results of a similar investigation. Researches into volatile oils, hydrocyonic, and other acids, and mineral elements, have also been mapped out by Mr Grimmett. The soil work will be undertaken*in conjunction with Dr. L. I. Grange, and here again it is hoped to duplicate the work of Ruakura and Palmerston North. Officers of both the Department of Agriculture and the Department of Scientific and Industrial Research will be used for these surveys, and a committee under the chairmanship of Mr Grimmett will co-ordinate all chemical studies for which every available officer will be co-opted. - Field Experiments “At Ruakura there are to be a number of field experiments. In the first place an endeavour will be made to reproduce the disease, and towards this end trials are to cover the following points:— “(a) Hard grazing in spring and summer, followed by grazing on fields flushed with irrigation. “(b) Hard grazing in spring and summer, followed by natural flush of grass stimulated with nitrogenous dressings in autumn. “(c) Hard grazing in winter, followed with nitrogen-stimulated grass in the spring. “(d) Dry feeding in winter, followed with nitrogen-stimulated grass in the spring (repeat in autumn). “On the prevention side, studies will be made under field conditions of: “(a) Sheep on paspalum the whole year. “(b) Sheep from hard grazing moved on to paspalum when the flush occurs. "(c) Paspalum when pastures are dry, and then on to autumn flush of feed. “(d) Sheep from hard grazing on to pasture shut up in December. “(e) Sheep from hard grazing on to pastures laxly grazed from NovemberDecember. “(f) Sheep on irrigated pastures during dry weather. “(g) Sheep from hard grazing on to autumn-sown grasses. “(h) Sheep fed on forage crops in late summer, and half kept on forages when flush of grass arrives, and half moved on to flush grass. “(i) Sheep fed on lucerne in late summer, and half kept on lucerne when flush of grass arrives, and half moved out on to flush grass. “(j) Sheep educated in hay and silage feeding during winter to get silage in summer, and hay when flush of grass comes.

“Arrangements have also been made to conduct comprehensive experiments on a farm where outbreaks of facial eczema have been reported for several years past.’’