H.—29,

CATTLE. Diseases scheduled under the Stock Act. Tuberculosis. — The number of cattle condemned under the Stock Act for tuberculosis during the year amounted to 6,791 head, being 5,932 condemned on clinical symptoms and 859 reactors to the tuberculin test. In each case compensation was paid in accordance with the provisions of the Act. The tuberculin test was applied to 14,780 cattle, of which number 859 reacted, giving a percentage of 5-8. In a severely infected herd, reactors to the tuberculin test three years ago showed a 20-per-cent. infection, two years ago the reactors were 8-14 per cent., and this year the reactors have dropped to 1-4 per cent. The tuberculin test is of very great value as a diagnositc agent in the detection of infected animals. Provided all the animals on a farm are tested at regular intervals, and provided care is taken to see that fresh infection is not brought in from outside, there should be no difficulty in cleaning up centres of infection. The total number of cattle, exclusive of calves, examined at the various abattoirs and meatexport slaughterhouses was 504,426, an increase of 3,839 on last year's figures. Of these, 38,203, or 7-57 per cent., were found to be affected with tuberculosis in varying degrees, a large percentage being only slightly affected. This indicates an increase of 0-19 per cent, infection amongst cattle slaughtered in these premises. So far as the tuberculin-testing of herds is concerned, the position is a voluntary one. It is, however, interesting to note that 13,754 cattle were tested at the owner's request. It appears necessary to give some protection and credit to owners who have eradicated the disease from their herds by repeated annual testing. The initiation of an accredited herd scheme would be an acknowledgment of the efforts of those owners who have endeavoured to supply milk from healthy stock, and an incentive to other owners to follow. The voluntary testing of herds supplying milk for human consumption does not go far enough, and from a public-health aspect it is recommended that all herds producing for town milk-supply should be tested and, if possible, accredited. Actinomycosis (and Actinobacillosis). —During the year 732 animals were condemned for this disease. Many animals were successfully treated for the disease during the year by the regular dosing with potassium iodide as recommended in selected cases. Advanced cases of the disease, with bone structure involved, do not readily respond. In the case of run cattle, dosing is impracticable in many cases. In other cases, owners are loathe to carry out the necessary repeated dosing. Malignant Growths. —The number of animals condemned was 145, compensation being paid in accordance with the Stock Act. Anthrax. —The Dominion remains free from this disease. Blackleg.—The number of calves vaccinated against this disease in the affected areas were Taranaki, 8,295, and Auckland, 21,924, making a total of 30,849. This shows a decrease of 5,001 on last years' figure, and would indicate that the number of outbreaks this year is less. Control by vaccination continues to give satisfactory results. Cattle-ticlc (Hsemaphysalis bispinosa). —On account of the dry and favourable season in the North, ticks were plentiful on stock in the early part of the season. No clean areas have been infected, and no serious spread of the parasite has taken place. Johne's Disease. —Unfortunately, it has to be recorded that new farms have been found infected with this disease in both the Taranaki and the Waikato districts. Although the disease was confirmed on a further eleven farms in Taranaki, it is important that only one case each has occurred on many farms in this district. Previously affected farms in Taranaki have shown no new cases since 1937 on nineteen farms, no new cases on twenty-five farms since 1936, no new cases on seven farms since 1935, and no new cases on four farms since 1934. In this district the position is rather hopeful and reassuring, and it is possible that a fair measure of control can be exercised. The percentage of reactors to the Johnin test in Taranaki is also low, and this again is a hopeful sign for the ultimate eradication of the disease in this district. The position in the Waikato is very different, and here the disease presents many disturbing problems in regard to control and eradication. During the year Johne's disease was found on eight additional farms in this district. A feature of the disease in this district is that, once a clinical case is diagnosed on a farm, many animals appear to soon become sensitized to the diagnostic agent, and the percentage of reactors does not decline even after repeated testing. This is a very disturbing feature which is not hopeful from a control or eradication point of view. In this district other measures than testing would appear to be necessary, and in non-pedigree herds some measure of cross-breeding may offer the best prospects of success. This suggests itself from the fact that grade animals appear to be more resistant than pedigree animals. Research into many aspects of the disease is needed to clarify the position, as the difference in incidence between the two districts of Taranaki and Waikato, and between these and clean areas is hard to follow. Non-scheduled Diseases. Mastitis. —This disease continues to occupy one of the prominent places in the diseases attacking the dairy herds in the Dominion. Although further research and investigation has been carried out and this work must continue, it is being recognized by many farmers that good general shed management is a prime factor in control. The test sets which were sold to farmers with a view to the early detection of infected animals are not being used as freely as they should. It is recorded that a big percentage of farmers are not

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