H.—29.

Research Work. Facial Eczema and Photosensitization.—A fairly widespread outbreak of short duration occurred in the Gisborne district early in April, 1942, but the percentage of sheep affected was not high and many of the cases were not very seriously affected. A number of small, scattered outbreaks were also reported in the Waikato. Grazing Trials.—Unfortunately, chemical difficulties were encountered in the preparation of suitable extracts from pasture collected during last year's outbreak, and this prevented any further advance in the discovery of the liver toxin. No clinical cases occurred this year in the paddocks from which pasture was being collected, but considerable experience has been gained in the methods of preservation and the chemical fractionation of pasture. Pathology.—Further study of liver pathology has been made- The bile ducts and veins of livers from animals affected with facial eczema and other forms of photosensitization have been injected with celloidin, and the surrounding tissue digested away so that the effect of the diseases on the size and distribution of these vessels can be studied. Alkaloids in Rye-grass.—Further investigations of these interesting compounds have been conducted with a view to determining their significance in plant physiology and their possible effect on the health of grazing animals. Although no evidence has been obtained which would incriminate them as the cause of any important stock troubles, it is essential that the significance of any unusual substance in prominent pasture species should be understood, and the investigations are proceeding with this end in view. Photosensitization other than Facial Eczema.—An area of St. John's wort has been established at Wallaceville to assist in the study of the disease caused by this plant. It has been experimentally shown that ngaio can cause photosensitization associated with liver damage. It is, of course, not suggested that this is the cause of facial eczema. A series of papers by officers of this Division and of the Department of Scientific and Industrial Research, dealing with the investigations into facial eczema, have been prepared for publication in the New Zealand Journal of Science and Technology. Sheep Mortality, Canterbury.—The work in Canterbury has been continued and further valuable data have been obtained concerning problems of sheep husbandry. Although a considerable amount of rain fell during the late summer and early autumn, 110 unusual mortality was experienced either on the experimental farm or in the district generally. Mastitis.—The milking-machine experiments at Wallaceville and the segregation experiments at lluakura have been continued- Experimental treatment has included the study of colloidal silver preparation reported on favourably in America, which has been shown to have some value in the treatment of chronic streptococcic mastitis, but it is doubtful if it will prove more effective than the antiseptic dye preparations which are already in use. Milking-machine Research at Wallaceville.—This work has been actively continued. Manufacturers of milking-machines are making use of the laboratory's facilities, discussing their problems with the research officer and submitting experimental accessories for trial before marketing. The rubber shortage has led to an intensive study of milking-machine rubberware, and it has been, possible to make recommendations on which emergency standards have been based, which is it believed will result in a twenty-five per cent, saving of rubber without any material loss of efficiency. Investigation of Non-stripping.—The shortage of farm labour has resulted in a further marked increase in the number of dairy-farmers abandoning stripping. In collaboration with the New Zealand Dairy Board, a careful examination was made of a number of dairy herds in which stripping had not been practised for periods of up to twenty-five years. The investigations indicated that, provided the milking-machine is kept in good condition and reasonable care is exercised in milking the cows, the abandonment of stripping does not result in any significant decline in producton or increase in mastitis. A full account of the investigation was published in the Journal of Agriculture• The controlled experiments at Ruakura are being continued. Semen-testing Service.—This work was again carried on at Ruakura, and samples were submitted from seventy-eight bulls, of which eight proved to be sterile, while a further fourteen were of low fertility. Artificial Insemination. —Artificial insemination was again used entirely in one herd at Ruakura, and further valuable data have been acquired concerning technique. Two bulls were used and the cows were divided into three groups to test different methods of insemination. Conceptions resulted from 61 per cent, of the inseminations from one bull, and from 53 per cent, from the other; eight cows out of one hundred and four remained empty. It is now certain that the use of proven sires can be widely extended in New Zealand by means of artificial insemination as soon as suitable organization can be provided. Contagious Abortion.—After a year's experience in handling the cultures and studying the effect of vaccination with the best strains of the contagious abortion organism obtained from overseas, some four hundred heifer calves were vaccinated this year. If staff and travelling facilities are available it is hoped to extend this work next season to a further number of herds in which serious trouble is experienced from contagious abortion. Toxcemic Jaundice of Sheep—An experiment has been commenced on a property in which this disease causes serious mortality, and regular observations are being made to determine the factors concerned in its development. Parasitology.—The effect on lambs of pure infestations with Ostertagia and Trichostrongylus have been studied at Wallaceville. The comparative response to internal parasites of some of the commoner crossbred lambs is being studied in Canterbury. A survey of the seasonal incidence of parasites in. lambs and calves, and a study of the best methods of control, is being made in several districts. Nutrition Experiments at Ruakura.—The experiments dealing with the nutrition of dairy cows, calves, beef cattle, and pigs have been actively continued, and some of the results have been reported in the Journal of Agriculture and the New Zealand Journal of Science and Technology.

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