DREAD MAMMITIS

Dominion, Volume 25, Issue 275, 16 August 1932, Page 3

DREAD MAMMITIS

Scourge Among Dairy Cows VACCINE TREATMENT Fight Against Disease Exactly what is lost by New Zealand dairy farmers each year as a result of the scourge of mammitis among dairy cows is not known, but it is generally agreed that the loss can be put down at a substantial sum, probably tens of thousands of pounds sterling. There is ample evidence that the disease is widespread, and its general and wholesale distribution demands that every effort be made to bring it under control as speedily as possible. The use of vaccine is now universally accepted as the only practical method of attacking the ravages of the troublesome germ of contagious mammitis. AU owners of sheep realise the necessity of keeping their flocks free from tick by way of dipping, and there is no reason why vaccines, offering as they do. the most satisfactory preventive means known against mammitis and various other bacterial diseases of dairy animals, should not be freely availed of. Mammitis is believed to enter the bovine system by the orifice of the teat. Ultimately it reaches the delicate parts of the udder which secrete the milk, and in severe cases the loss of one or more quarters will become involved. Systematic Treatment Essential. Where contagious mammitis is prevalent in a herd of dairy cows the risk of massed infection is exceedingly great unless some form of systematic treatment Is adopted. For this purpose preventive vaccines designed to give an immunity have been designed. An unfortunate fact.about mammitis is that the better breed of cow and the highest butter-fat producers are the most susceptible to it. Knowing the heavy losses ' incurred every season through the ravages of mammitis, and realising the urgent necessity of a national effort to stamp out the disease, which is becoming a greater menace every year, the National Dairy Association of New Zealand has entered the campaign. Success can only be achieved by the closest co-operation between scientist and farmer, and the National Dairy Association will form a connecting link between farm and laboratory. A special department has been established by the association to give the closest attention to inquiries and the execution of orders for “Emmunin,” the distribution of which has been undertaken by the association. Result of Intensive Study. The “Emmunin” method is the outr come of a long period of intensive study by a highly qualified bacteriologist, and the antigen is prepared under his personal supervision, and with the aid of equally qualified assistants. Farmers now have an unrivalled laboratory service at their disposal established for the sole purpose of assisting them to combat mammitis, and it is hoped that full use will be made of the facilities available. There is a vast amount of evidence to show that mammitis is the cause of an enormous annual loss to the dairy industry of New Zealand, and the alarming Increase in the ravages of this disease during recent years is causing the gravest concern to farmers and others interested In the welfare of the industry. The very nature of the disease makes it particularly prone to attack heavy milkers, and thus it is very often the most valuable animals in the herd that are stricken. There is a popular belief that mammitis is caused by a single type of infection or germ, and by this one only. Nothing could be further from the truth, although it is possible to say that, generally speaking, it is a streptococcal infection. Many Different Organisms. ' Intensive investigations carried out by the scientists at the Emmunin laboratory have clearly established that a great number of different organisms are responsible for the disease. The types show distinct variations in different districts, and even in neighbouring herds, and it is not uncommon to find two or more members of one group to infect an animal at the same time. It often happens that a secondary infection with another germ is present as well. . If the disease were due to one type of infection only the preparation of an effective standard remedy to combat it would become a comparatively simple matter, and probably the disease would have been stamped out before ever it became so widespread as it is 5 to-day. It is therefore quite obvious that a standard remedy cannot hope to cope with all cases and be 100 per cent, effective. For instance, it is quite possible to destroy one type of infection, only to find an organism of a different class setting up a fresh cycle of infection in the herd. The “Emmunin” treatment for mammitis is the outcome of a long and intensive study of the causes of the disease, and is based on a realisation of the fact that the variety of types of - infection makes it necessary to treat each case individually. From the samples of infected milk sent to the laboratory by the farmer, the different strains of organisms causing mammitis are isolated. The antigen or vaccine is prepared from these strains, and it is “autogenous” to the animal or herd from which the samples were taken. In other words, the antigen is prepared to deal with the particular types of infection revealed in the samples. The astigen contains no live organisms (as is sometimes believed), but substances, which, when injected into the tissues of the cow, produce “antibodies” which enable the affected animal to resist the germs entering the udder. This power of resistance is termed immunity. Immunity Rises Rapidly. After treatment with “Emmunin” immunity begins to rise rapidly, and then keeps at a high level for a period of from six to eight months. In severe cases of acute infection it may take four or even six weeks after treatment before the. antigen has taken full effect, and the disease is cleaned up. After six to eight months, the degree of immunity gradually begins to fall again, but just at this stage a very small dose of “Emmunin” (only a fraction of the original treatment given when first, immunising the animal) is sufficient to jifise the plane of immunity to its former level or even higher. The animal has become sensitised to the antigen From the date on which milk samples arc received in the laboratory, it requires from seven to ten days to prepare the Emmunin, i.e.. if all goes smoothly.in the process, cultures are not contaminated, and so on. While it is fully realised that prompt treatment of mammitis is very desirable, and delays may result in the loss of valuable animals, it is impossible to hurry the culturing process which must take its natural course of development. To meet urgent cases the laboratory has therefore decided to keep on hand a supply of “standard” antigen and will on request forward sufficient of this for a preliminary inoculation of serious cases, pending the preparation of the autogenous antigen. This will have the effect of checking the disease until specific treatment can be given.—P.B.A.