SCOURGE OF MASTITIS

New Zealand Herald, Volume LXXIII, Issue 22615, 31 December 1936, Page 15

SCOURGE OF MASTITIS

RESEARCH IN DOMINION OVERSEAS INVESTIGATION! THREE TYPES OF INFECTION Br COLIN CAM F.RON It is very welcome news that serious research is at last to bo commenced upon the control of mastitis in the dairy herds of tho Dominion. This 6eourge has become such a serious menace to the industry that it ranks with the most urgent problems facing the dairying community. To assist tho officers of the Department of Agriculture in this important project the Government has secured the services of an eminent American scientist who is regarded as a world authority on the disease. Research Results Published This specialist is Dr. George J. Pucker, Ph.D., of the New York State Agricultural Experimental Station. He is familiar with every phase of mastitis research, which has been extensively prosecuted in the United States. This country is indeed fortunate in having the benefit of the experience of such an authority as Dr. Hucker, and the result of his work in collaboration with the research workers of the department •will be awaited with keen interest. By a happy coincidence, the decision of the Government to organise an effective campaign against mastitis synchronises with the publication of tli* latest findings of British and Continental research upon the disease. Since these provide not only highly interesting indications as to the most promising line of investigation, but also very useful descriptions of the methods of control already applied with gratifying success, it is proposed to give a brief outline of the progress which has been recorded. A Great Advance It has been definitely established that mastitis is caused by bacterial infection. The bacteria responsible for the disease are known as the streptococci mastitis- Until recently it was thought that there was only one type of streptococcus mastitis, but it has been discovered that there are no less than three groups of streptococci associated with the disease. The recognition of these threw groups constitutes an important advance, since one vital step toward checking mastitis is the detection of the casual organisms by applying suitable tests to the milk from infected cows. A technique has now been developed whereby the disease can be 'diagnosed at an early stage. This enables the infected animals to be isolated and treated when the diseaso is passing through a phase during which it is most susceptible to treatment. The next important matter upon which finality has been obtained is the means by which the bacteria gain entrance into the system of the cow. It was at one time considered that infected food was a possible source of the disease. But searching tests, made by placing strong cultures of the virulent streptococci in the food of animals under observation, have shown conclusively that mastitis cannot be contracted through the consu m ption of infected feeding, matter. Just as decisive as this negative result were the positive effects of treating the teats of cows in various ways with cultures of |he bacteria. The most certain way of inducing mastitis was found to/ be the injection of the streptococci into the teat canal. Chronic infection, for example, was produced in this way in each of ten machinemilked and forty hand-milked cows. Numerous tests have proved beyond doubt that the teat canal is the normal .way of entry of the mastitis bacteria. \Vhile this fact has been established, it is interesting to note that it was found irripossible to transmit the disease bv using the same milking machine for infected and healthy animals. In a particularly searching test, one diseased and two clean cows were milked on the same machine for several weeks. The healthy animals did not suffer the slightest contamination. In the next article, it is proposed to give the latest conclusions of research scientists concerning various means by which the disease is contracted, and to outline the methods liecommended for the control and prevention of the disease.