PRESENT DAV CONDITIONS

Taranaki Daily News, 11 September 1934, Page 22 (Supplement)

PRESENT DAV CONDITIONS

INTENSIVE RESEARCHES • • - v ASSISTANCE TO DAIRY FARMER. EFFORTS OF STATE OFFICIALS. Amongst stock diseases present in the Dominion, reports Mr. W. .C. Barry, Director, Livestock Division, Department of Agriculture, those which occasion the greatest economic loss, namely—mammitis, abortion, and sterility in dairy cows, have all been the subject of intensive research during the past decade, not only-in New Zealand but in practically every country in which dairying forms an integral part of agriculture. The outcome of this research has not been the discovery of a certain cure or preventive of those diseases, no more than a specific, cure for tuberculosis, infantile paralysis, or goitre (to mention but a few) in the human subject has materialised. But if a cure for those dairy cow diseases has not eventuated, it is safe to assert that our knowledge respecting them has largely increased in recent, years, which knowledge practically applied and disseminated has helped and continues further to help the dairyfarmer in lessening his losses. In contributing to this research the New Zealand Department has done remarkably good work, and without meaning to be in any way boastful, it can be asserted that the research being done in connection with mammitis and sterility is regarded as being even more advanced than that of overseas investigators. PREVENTION OF ABORTION. Regarding abortion disease, experimental work in connection with vaccination which was conducted in Taranaki a few seasons ago, gave no promising results, and it is generally accepted that vaccination in this disease is of no practical value. There can be no doubt but we have now reached a stage respecting abortion diseases in New Zealand when through dissemination of the infection, an immunity of the act of abortion is taking place. Thht is to say, that although the presence of the disease in cows is , not by any means lessened the actual number of abortions occurring on individual farms is fewer than some years back. The agglutination (blood) test for the disease, which is carried out free of charge at Wallaceville, enables a' farmer to know which of his cows are infected. It does not necessarily follow that a cow having the infection will abort, but such a cow is a potential danger in spreading the infection through discharges after a normal calving. The agglutination test is being largely availed of by farmers who are endeavouring to adopt measures of control. Complete separation of herds into infected and non-infected cows is as a rule impracticable, but much good can be done by isolation of aborting cows, destruction of membranes and foetus, disinfection, etc., and the provision of separate calving paddocks for cows reacting to the agglutination test CONTAGIOUS MAMMITIS.' In connection with mammitis, the Department has introduced a method of control by which the detection of cows infected with mammitis can be accomplished before any clinical symptoms or naked-eye alteration in the milk can be observed. The method consists of bacteriological examination of the milk from every cow in the herd, carried out

monthly. This is done free of charge by the Department, and the farmer advised of results. According to the leucocytic count of the milks, cows are grouped into (a) healthy; (b) infected, but not showing any symptoms; (c) definitely affected cows. Control depends on the milking of these groups separately in the order named. This, together with certain hygienic precautions in the milking shed, constitutes the basis of the scheme. It admittedly involves trouble in the milking procedure, but it is at the present time the only available method by which control of spread of- mammitis can be effected. In many dairying districts numbers of farmers have availed themselves of the method, and are apparently satisfied with the results; at any rate they are desirous of continuing the practice. Recent research work at Wallaceville dealing with the bacterial flora of the teat duct, promises to throw some light on the question of “carrier” cows. Certain predisposing influences arising mostly through carelessness in proper hygienic precautions and proper manipulation of milking machines, have a very marked influence on the incidence of mammitis. The importance of the early detection of the disease is very great, and in this direction dairy-farmers have at their disposal the free examination of milk samples by the laboratory. There is no reason why if proper precautions be adopted, mammitis should spread to a larger number of cows in a herd. Farmers should not mislead themselves into the belief that it is only a “hard quarter” or a “chill” until it has been proved to be non-contagious. The field staff of the Live-stock Division is always ready to assist farmers in the best means of control. * STERILITY.

Sterility in cows may be either permanent or temporary. By far the greatest trouble is experienced from that condition known as temporary sterility, or “returning to the bull.” It is probably safe to say that in no other country has such intensive research been instituted against the loss occasioned to the dairying industry from this cause, as in New Zealand. During the past six years, it has been the subject of very close study, both in the field and laboratory. Special veterinary officers were detailed for this work, a considerable part of it being accomplished in Taranaki. The results have thrown considerable light on the trouble, although a definite solution cannot be claimed. Briefly temporary sterility would appear to be.due to one of three causes. (1) Mineral deficiency. (2) Partially infertile bull. (3) Infection. Where phosphatic deficiency is very marked, cows may show complete absence of bulling. In lesser degrees, or where deficiency of phosphate,is accentuated by an increase of lime in the pasture, conception is also interfered with to some extent. The infertile or partially infertile bull accounts for a number of cows not holding. Infection of the bull passed on to the cow and then back to a new bull is not uncommon. It is frequently responsible for trouble, even though young bulls are being employed. Milk fever is not as prevalent in Taranaki as in other dairying centres of the Dominion—notably the Auckland Province. A suggested reason for this is a possible higher availability of lime in the pasture. Another condition met with in other districts is the so-called “grass staggers” of cows which occurs at variable periods up to six weeks after calving. In some of its aspects this trouble is closely related to milk fever. Its occurrence in Taranaki is fortunately extremely rare. The glandular disease of sheep known as lymphadenitis has of recent years, owing to the importance placed on its occurrence in carcases on the Home

market, become of economic importance to sheepowners. The most common way in which sheep become infected is through cuts at shearing time. The division has formulated a system of advice to the farmer on its control and suppression. It can be detected in the live sheep by palpation, and affected sheep can by this means be recognised and segregated, thus minimising the spread through a flock. Every sheepfarmer who has evidence of this trouble amongst his sheep should take the necessary precautions to eradicate it, and thus help to reduce the number of sheep rejected for export on examination at freezing works. The trouble known as “foul foot” of cattle is known to cause considerable loss to dairy-farmers. Affected cows very quickly go off in their milk yield, and the disease will readily spread in a herd. It is caused by germs entering through a break in the horn of the foot, and ending perhaps in necrosis and suppuration. It is undoubtedly associated with broken, muddy and dirty entrances to cow-yards and exits from

milking sheds. In those places the cows pick up the infection in their feet, although admittedly it can occasionally he met with on places where such conditions do not prevail. Treatment of the disease is not too satisfactory, but elimination of broken ground surfaces at gates and exits of milking yards will go a long way to help. Investigation is being made with a view to ascertaining any predisposing condition of the animal. This appears a desirable opportunity to say -a few words regarding Johne’s disease (pronounced “yo-nay.”) This disease gets its name from Professor Johne of the Veterinary School of Dresden, who first discovered the organism causing it. Its presence has been noted in Taranaki for the past six years, although .in all probability it was there previous to this, but was not detected. It is a disease of adult cattle and is of the nature of a chronic, bacterial enteritis. The symptoms are characteristic when the disease is well developed, and are those of chronic scouring with emaciation. The scouring will be at first intermittent, with perhaps apparent intervals of recovery. Later, however, the diarrhoea becomes chronic, and the animal is frequently reduced to the condition of a “piner.” The disease is caused by a germ known as Johne’s bacillus, which becomes located in the membrane lining the • intestines, causing inflammation, with the symptoms described. The disease is a slow, insidious one in its onset, and an animal ■ might be affected for a long time, before symptoms become apparent. Johne’s disease is a scheduled disease under the Stock Act, and slaughter of affected animals is obligatory. Farmers are requested to report suspicious cases, as neglect in this respect will only lead to extension of the disease. The germs are passed on to the pasture with the droppings, to be picked up by other animals. A diagnostic test is used for the detection of the disease, the agent being known as Johnin. Mr. E. H. Stephens, Government Veterinarian, Stratford, has been carrying out some tests where necessary. Stockowners should in their own interests report suspicious cases to the nearest stock inspector, when investigation will be carried out. At the present time the existence of Johne’s disease in New Zealand is known only in Taranaki and the Waikato. Let it be said that in the prevention of disease, stock management and feeding play a most important role. With the object of instructing the farmer in what is referred to generally as animal husbandry, the Live-stock Division has enlarged its activities in advisory and instructional work along the lines . of proper care and management, feeding,

and what might be referred to as the hygiene of the dairy cow and cow-shed. There is evidence that this phase of instructional work is appreciated by farmers. Given a good constitution in the animal, and proper food and management, disease, apart from infectious conditions, should, strictly speaking, be a negative quantity, and even in the case of infectious disorders should be materially reduced.

With the present day tendency for specialisation in respect to breeding for high production and increasing butterfat returns, the dairy cow has become converted into more or less an artificial product, giving as a result of inherent powers transmitted by heredity, an abnormal quantity and quality of milk. It is only reasonable to expect in such instances, unless care be taken to replace to the animal system, in so far as we are able, the drain occasioned by lactation and pregnancy, that vitality must be lowered, and when this state arrives, the door is opened for disease in various forms.