ECZEMA AFFECTS SHEEP

Taranaki Daily News, 10 April 1935, Page 9

ECZEMA AFFECTS SHEEP

OCCURRENCE IN TARANAKI

DEPARTMENT’S INVESTIGATIONS.

THE DISEASE NOT INFECTIOUS.

ADVICE GIVEN FOR TREATMENT.

Facial eczema affecting sheep, which first made its appearance in Poverty Bay, is now prevalent among sheep in Taranaki. The Department of Agriculture, however, says the disease is neither infectious nor contagious,

Following investigations the department thus summarises its findings:—

Serious reports of the prevalence of facial eczema were first received from the Poverty Bay area, and two officers proceeded there forthwith. A week was spent conducting a field inquiry into the matter and collecting specimens for detailed examination at Wallaceville. The officer in charge of the veterinary laboratory at Wallaceville is at present on a second visit to Poverty Bay to collect further special material that is required for research purposes, and an experienced field veterinarian is conducting an inquiry in the Manawatu. into the factors related to the occurrence of the disease.

Farmers who have experienced the condition among their sheep are only too familiar with its appearance; Briefly, there is first irritation and a tendency to droop the ears and shake the head. Soon the ears and skin about the face, eyelids, nose and lips swell, and these parts are acutely sensitive to light, becoming greatly irritated thereby, so that the unfortunate animal rubs and scratches itself till the skin about the face is cracked and raw. Then the swelling (due to fluid under the skin) subsides through the escape of the fluid, and the raw surfaces fester unless kept disinfected.

EFFECT UPON CARCASE.

If an affected animal is killed its carcase is found to be muddy in colour or even jaundiced (yellow), and the liver is found to be abnormal. The most striking abnormality of the liver is that the bile ducts running through it are thickened and partly or completely blocked with thickened bile, while the gall bladder is generally enlarged and distended. The* department has considered that the disease is somehow brought about by the flush of green feed following on dry conditions. While many farmers are loth to accept this view, there is much scientific evidence in support of it as well as the observed fact, both in New Zealand and in other countries, that the disease occurs when rain and warmth have combined to bring about a rapid growth of feed. The scientific evidence on this point has resulted from several years of endeavour by workers on animal diseases in South Africa. It has been found there that if the ducts which lead the bile away from the liver of a sheep towards the intestine are tied, so as to dam the bile back, the symptoms of facial eczema soon occur provided the animal is receiving green feed and is subjected to light.

EXCESS OF CHLOROPHYLL.

If the animal is on green food but kept in darkness the symptoms do not appear, nor are they seen if such an animal has been on a diet free from chlorophyll (the green colouring matter of plants) and is kept on such a diet after the operation. These facts, in conjunction with the observation that the disease appeared in naturally occurring outbreaks bn more than one type of green feed, were followed by the discovery that in the blood of affected sheep there was an abnormally large ataount of a substance derived from chlorophyll and called phyllocrythrin. When this substance was isolated in a pure state and injected into healthy sheep it induced all the symptoms of facial eczema, provided' they were exposed to light. The evidence points to this substance being formed from the chlorophyll of the green feed that is eaten, by the agency of bacteria, etc., in the stomachs of the sheep, and it might be asked why, if that is the case, facial eczema' does not occur in any animal which eats green feed. The answer to that lies in the state of the liver in the affected animal.

It will be remembered that the South African workers found that symptoms of facial eczema occurred in sheep whose bile ducts had been tied and which were receiving green feed. In cases of facial eczema the state of the liver is comparable to what would occur if the ducts were tied—there is a stoppage in the circulation of bile.

“Why the stoppage occurs is not yet clear and it is the point which is now being investigated. It, too, may well be associated with the nature of the feed, and it is a fact that few farmers will dispute that if the disease occurs in a flock on rich green feed and they can be removed on to harder country where the grazing is sparser, coarser and more fibrous, few, if any, fresh cases will occur. ■ ‘ “What is required in the treatment of affected sheep is firstly shade.. The wool shed may be utilised for this purpose. Secondly, a purge to empty the bowels and stimulate the flow of bile. Thirdly, a soothing and antiseptic emolient dressing for the affected parts. After a few days in the shed, where they should receive water and some sweet Jiay to pick at the patients should be let' out at night before trying them for increasing periods of daylight grazing. The unaffected sheep should, wherever possible, be moved on to harder country with drier and more fibrous food. If this cannot be done, and in many cases it is impossible, they should be given as shady a paddock as possible, and hay should be offered them in the shady places. Frequently this is not eaten, but it is worth trying and will do good if the sheep can be induced to eat it.