JOHNE'S DISEASE

New Zealand Herald, Volume LXXIII, Issue 22545, 9 October 1936, Page 15

JOHNE'S DISEASE

DEPARTMENT'S ACTION STATEMENT BY MINISTER DIFFICULTIES OF CONTROL An assurance that the Department of Agriculture would continue to make every endeavour to deal with Johne's disease among cattle in the Dominion, not only by the adoptipi. of presentday known measures, but also by the furtherance of research into the disease itsell, was given by the Minister of Agriculture, the Hon. W. Leo Martin, in a statement on the subject. The Minister stated that in view of the possibility of any scare being created in the minds of stockowncrs through any misconception of the nature of the disease, the characteristics of which were not generally known to farmers, he considered it desirable to issue a statement referring to the disease, and the action which the Department of Agriculture is taking with regard to its control. Johne's disease is one which develops very slowly and insidiously, stated the Minister. It is due to a germ, not unlike the germ of tuberculosis, but whereas the latter mainly affects the glands, lungs and other organs of the body, the Johne's germ attacks the lining membranes of the intestine, causing chronic inflammation and thickening. As a result of this, there is at first intermittent scouring, which later becomes persistent, and is associated with rapid emaciation, resulting eventually in tho animal's death. Symptoms are rarely seen in cattle under three years old, and are most likely to occur following calving, at which time an infected cow is often observed to develop the symptoms of scouring and to break down very rapidly. Treatment is of no avail. The manner by which the disease is spread is by the germ gaining entrance to the animal's system in food and water. The germs are disseminated in the droppings of affected cattle. Difficulties of Control

"One of the greatest 'difficulties connected with the control of this disease is the lengthy period which elapses between the time of infection of the animal and the appearance of symptoms," stated the Minister. "This is generally not less than two years, and may be considerably longer." Experiments with the Johnin test, which is a diagnostic test to detect the presence of the disease before symptoms arc shown, were described by the Minister, who stated that the livestock division of the Department of Agriculture decided to test the value of Johnin testing at half-yearly intervals as a means of eradicating the disease from two affected grade herds in Taranaki. This experiment had been under way for nearly two years, and so far appeared to have given promising results. "The department is fully alive to the necessity for strenuous effort in an attempt to limit the occurrence of this disease," stated the Minister. "It must, however, be reiterated that control of Johne's disease presents most serious difficulties —a fact which is freely admitted in all countries in which it exists to-day. Total eradication does not appear, in the light of present knowledge, of the disease, practicable, and attention is being directed to efforts to reduce its incidence on farms on which it occurs. To this end the department intends to carry out periodical tests of animals on such farms, and by this means it is hoped to detect early cases, and by their elimination control further spread of the disease." Use of Lime The Minister added that reports from the Continent, and also from the Channel Islands, referred to the apparent good results following the application of heavy dressings of burnt lime to affected pastures, the effect of lime apparently being inimical to the life of the germ in the soil. This aspect was one which was being followed up by the department. Also, regulations had already been made providing for all imported cattle to be Johnin-tested. Since the disease was not known to occur in the South Island, the regulations also provided, where the department considered it necessary, that cattle from the North Island be tested similarly before a permit was issued for their shipment to the South Island. Slaughter ol Herd "Some concern has been occasioned in the minds of farmers on account of recently-published statements respecting the slaughter of an entire herd in Taranaki owing to the presence of Johne's disease," stated the Minister. "In this instance, such action became necessary owing to the financial implications being such that without departmental interference, dispersal of the herd would have taken place, and as the incidence of the disease was very heavy jr. this herd, slaughter of all animals was carried out with a view to preventing infection being carried to other farms.

"It must not, however, be assumed that this policy will apply to other farms on which the disease is known, such action being in this instance deemed necessary owing to the exceptional circumstances of the case. In fact, it is confidently expected that the method of twice-yearly testing of all herds on farms where the disease is present, should enable the disease to be controlled with an absolute minimum of stock having to be slaughtered."

The Minister added that there was no occasion for any alarm on the part of stoekowners in connection with the matter. In the meantime, farmers were advised to bring to the notice of the department any instance of cattle showing symptoms suggestive of Johne's disease.