Farm & Station

Gisborne Times, Volume LXXXIV, Issue 12804, 7 March 1936, Page 12

Farm & Station

FACIAL DERMATITIS IN N.Z SHEEP.

A PHOTOSENSITIVITY OF UNPIGMENTED SKIN

OUTBREAK IN POVERTY BAY Bv Dr. C. S. M. TTopkirk, Officer in Charge, Veterinary Laboratory, Department of Agriculture, WatlaceviUe Uncial dermatitis, I‘ocial eczema, high end, and sunburn nvo names given to a. condition of sheep where the exposed implemented .skin of sheep and cattle- reacts to light, ho coining severely burned. Two types are known, one being fairly prevalent in the South Island along alpine foothills and hack tussock-country, while j.he other has been seen mainly in the North Island during excessive autumn flushes of feed following prolonged dry summer spells.

HISTORICAL An oedema of flic, skin oT sheep and tho white areas of rattle has been known for a considerable time in connection with ingestion of St. John’s wort (Hypericum pel foratuni), buckwheat (Fagopyrum csciilentum), Trill ulus terrestris, and' certain modicages and trefoils. Experimental trials mainly in the United States of America, Australia and South Africa showed the unpigmented skin only was subject k injury, there* being elements in tho plants mentioned which predisposed unpigmented skin to tho harmful effect of ultra-violet rays. The injurious photosensitising agent is a flouresoont- body and mainly flo-wr-escenl dyes and drugs have that acr tion. examples being haematoporhyrin, (pi ini no, eosen, rose Bengal, inthvlono blue, chlorophyll, phylloery--1 lirin, etc.

While considerable work hub been carried out. in other countries on the photosensitivity due to S- John’s wort the most valuable work on the whole question seems to ho that performed in South Africa in connection with the disease “Geeldikopp,” caused by ingestion of the plant Trihnlus. In this work sheep with biliary fistuhie were used and the bile was obtained after feeding of the experimental plant. In Trihnlus feeding two factors were found to work in combination, the one a, liver-mpset-ting factor. referred to as the icterogenic factor. and the photosensitising factor which results from a breakdown of the chlorophyll-content of the plant.

In New Zealand facial dermatitis or fiacial eczema resembled in its external symptoms “Geeklikkop” of SoutJi Africa. It- is associated with a fast growth of pasture in the autumn Allowing a condition of drought. Tho various autumns off 1010. 192-5. and 1020 were- all of that- description. and large numbers of sheep and cattle became affected. On those occasions' the condition was apparently not recognised as photosensitivity. A condition of scabby mouth duo to virus infection must not he confused with photosensitivity. In the former the ears are rarely, if ever, affected. RECENT OUTBREAKS Of tho two conditions that in the South. Island is suspected to result from ingestion of n« species of Hypericum or St. John’s wort. Several species of Hypericum have been found around lagoons and near damp areas on stations in the affected areas by Dr. IT. H. Allan, systematic botanist to the Plant. Research Station, and experimental work is centred round flie plant at present. Owing to> the courtesy of Mr. T. T>. Burnett, M.'P-,. and owner of Mount Cook Station in the Mackenzie Country, 560 acres of an affected, block have recently been set aside and stocked with merinos especially to- elucidate the problem in that area. Also plants have been gathered for experimental feeding of stock at AVallaccville.

In the South the position lias not been ns serious as in the North, for if sheep were kept off affected blocks during December, January and February very few cases of dermatitis occurred. Further, there have been no bad a f'ter-cffects as in the photosensitivity of the North Island, for livers are on no way damaged. The North Island outbreaks have, however, always been of a serious nature. The outbreak of pbotosentitivily in (be autumn of 1925 was very wide in ils distribution, most areas being affected except for Hawke’s Bay and flic Wairarapa, where very few cases were seen. Cattle are noticeably effected in the Waikato and Bay of Plenty. As a rule high bill country was fairly safe, only comparatively few affected lambs and sheep being seen. Rich flats were particularly dangerous.

HEAVY LOSSES IN POVERTY BAY

In the Gisborne area observations were made after the initial outbreak of the trouble. There were no premonitory signs, and many thousands of sheep became affected in the same week. The same applied broadly to other areas. Rainfall in the Poverty Bay district during the summer had been so short that the pasture of the whole coastal area was dried up and in most cases eaten out by sheep and cattle. Inland’ on the hack high hill country precipitation was sufficient to keep the grass green, though it remained short. On such pastures no photosensitivity occurred. Rain commenced to fall round Gisborne on 7th. February, and the weather remained warm,, overcast, wet and dull for some weeks thereafter. Actual sunshine was intermittent and of short duration for that period of the year. As a 1 result., of the rainfall and warmth there was a fast-growing flush of.pasture, but, contrary to cxpoctntions it is said that scouring in ■sheep and lambs was noticeably absent. Oedema of the bead occurred first on February 21, and many cases in the district wore reported hy February 25. Several owners of rich flat land were heavy losers, one miyri having at least 500 sheep and lambs affected, while hill-station owners may

(By ’’RTTSTTCTJS.”)

have noticed twenty to fifty animals affected- Bam and ewe lambs and all older sheep irrespective of sex were alike affected. True, black-faced sheep such as Suffolk's ivci'e not affected,, but B-omneys and South downs wore very susceptible.

Pastures on • the flat contained clovers, trefoils and the usual grasses such as rye-grass,. crested dogstail, ffafstai], cocksfoot, etc., and ordinary weeds. No plants which one could .suspect of causing photosensitivity were to he seen except- lmrr clover, which grows well on the Gisborne flats and is considered ’ suspicions. However, burr clover js not- common in other parts of the country where liacial dermatitis was seen.

The sheep-owners of the district stated that, the paddocks had boon well ca(on-o.ut by cattle during the dry weather. The rain brought a. quick flush of feed which the cattle were not able to control successfully, and which had perforce to he given to sheep of all classes. Whore cattle had been able to control the feed very little or no oedema developed in sheep. .Photosensitivity developed in some cases in two days after sheep wore placed on luscious pastures, hutusually it took -a litlle, longer for trouble to develop.

An interesting point was mentioned in the district:that sheep, and particularly lambs, had not fattened a.s well in the dry weather a.s is usually the case. This was borne nut in meat works figures, for weights wore considerably less in the lambs being put. through for the fat- lamb trade. A NTE-A r 0 R TEA r A PPE AR A NOE The first suggestion of photosensitivity was a. shaking of the head and gonern-l restlessness- The ears quickly became oedema tons and drooping, this being followed by a puffing of the eyelids, face, tongue, lips and submaxillary space, and even in some cases the legs. In those sheep in which tho wool was inclined to open along the hack, the skin of the hack swelled, thus ruining (ho pelt. The temperature rose to as high as 107 deg. E. Sheep actively sought- shade and disliked being driven nnf, into the brighter light. Irritation of the skin caused the sheep to rub the skin off the ears, eyes and lips on fences, .ground, etc., which caused severe abrasion with subsequent infection and scab formation. Ophthalmia developed and ulceration of the cornea was not uncommon from injury, while nostrils were frequently almost entirely blocked by scabs and catarrh,. All mucosae showed an icteric condition ranging from light, muddy colour to a deep yellow. Urine was dark and frothy. Black pigmented areas of skin remained normal. Sheep unable to ohtain either travelled round the fence-line in an endeavour to break through, or they handed together with heads hidden between the bellies of .other sheep. Sensitivity to all light was most marked, rest being obtained by affected animals only in dark sheds. AVhen shade was unobtainable the skin injury was intense and abrasion became so severe that it was necessary to -sinlighten the animal to put it. out of pain. Tf sheep were placed in wool sheds at the first indication of irritation, then face lesions quickly recovered. POST-MORTEM APPE-ARANCE Tncision in the ahi'ased areas, whether, head, hack or logs, showed an intense oedema of the subcutaneous tissue. The fluid was strnwcoiourrd .nr oven more dimply p.'g-menl-ed. Lungs, heart, .spleen, alimentary canal, and kidneys wore aIT normal, though there was some oedema to be noted in the. pelvic fat of the kidney. Blood clotted normally, but the serum was Extremely "yellow. Urine was dark, but not port-colour-ed, as in so-called “enzootic icterus ’* Tho liver was the chief -seat of damage. In all cases damage ranged from simple cholangeitis (inflamm.v tion of the bile-ducts) to a stale of deeply bile-stained necrosis of liver cells. In acute eases of the disease the liver was yellow-ochre coloured. The liver showed in many cases a mottling of the surface, the lighter areas appearing to follow the course of certain veins. The gall-bladder was distended with a dark green bile, and lymph channels leading from the livc-r contained a greenish lymph- The most interesting point to be seen in all livers was the thickening of the main hilo-.ducts leading from the lobes, particularly the left lobe. Tn normal sheep the bile duels are. difficult to pick up. bill in sheep with derma liti's this thickening was marked and tho duct stood- out as a white cord, very. similar to chronic infectn*tion with liver fluke-. The duct was found to he partially blocked with a. brown, amorphous, inspissated mass of debris. Where the cholangeitis was of some standing tlic liver was hard and cirrhotic. With the partial damming Track of bile jaundice h«d occurred and hilo stained the. body tissues <ys well as the liver-cells. Toxic changes in the liver, shown by mottling, probably occurred as a result of the inability of damaged livor-eells to deal with toxic products brought in the blood-stream from the alimentary canal. The main bile-duct to the duodenum was at all times patent. Sections of liver examined under the microscope showed a, very great increase in bile-capillaries. In some eases cirrhosis was commencing in the liver supporting connective tissue about the bile capillares, and in quite a number oli cases cirrhosis was becoming of a perilobular type and gave promise of going further. There was no sign of haemorrhage areas in the livers from animals suffering from photosensitivity such as would have been seen in acute ragwort poisoning.

LIVER INSPECTION AT HAITI WORKS

Two facts of importance were evident in the initial survey of the disease, one photosensitivity and the other liver damage. Both required ■explanation. It would seem that the photosensitivity developed- only where there was liver damage, but liver damage did not necessarily produce

photosensitivity.' Liver efficiency tests with rose Bengal showed definite damage in the liver of the living subject. A special inquiry was therefore mado into the state oP sheep and lambs’ livers in the Gisborne area. At Kaiti Freezing Works many thousands of livers were observed, and where necessary the holding from which the sheep came, together with information concerning the sheep, was obtained. A large number of livers were being discarded for hardness and mottling. This state of affairs had commenced early in January and: was quite unusual. Although only a percentage of sheep with affected livers were photosensitive, animals without liver lesions were not affected. In one or two lines where all or practically all livers were normal, no rases of head oedema had been seen and such lines came from green hill country. Although much thought has-been given to it, the reason for liver damage and the exact time at which such livers became damaged, whether before or after the flush of grass, is unknown and is a matter for Mhvflther research- .Several theories suggest themselves, hut lack proof at present. Once the liver became damaged, however, the flush pasture could readily cause the photosensitivity. Much work lias >,„en carried out in South Africa on nilorophyll of plants, and it has been shown that the gi-ceti colouring matter is broken down, in the rumen to form a floureseent body -—phyllocrythrin—some of which is normally absorbed and secreted by the liver. With the dnmming-back of bile into the blood-stream this coloured body makes the akin sensitive to light. T)r. Mngeiirite Henrici, also working in South Africa, has shown that chlorophyll of plants alters considerably not only from dry to wet season, hut also from day (o day and hour to hour. Tt is high in the young green leaf, but low in the dried or wilted plant. Sunlight during the day decreases if, find resynthesis occurs during the night. On dull days, ns Gisborne had, the chlorophyll-con-tent remained on a high level. Everything was therefore in on optimum condition for photosensitivity to occur provided (lie livers were damaged. AFTER-EFFECTS A further important aspect of the photosensitivity of the North Island was the very serious after-effect. The livers wore, so badly damaged that sheep were slow in recovering their energy and condition. Many died within a- lew weeks, others lingered on and died later. Fives failed to teoneoive, and lambing percentages amongst affected ewes were very low. If sheep fattened and were sent, to the meat works the livers were found to be extremely badly damaged. The left lobe was completely atrophied, while the remainder of the liver was bulbous from regeneration of liver cells. Rn hndl.v damaged was the liver that affected sheep could never bo entirely normal. Fivers appeared wimowliat similar to those caused by severe ragwort, poisoning, but fortunately the two conditions can be differentiated. The damage appeared to have originatd from occlusion of the bile-duets and not from blockage of the blood-vessels in the liver. At present as a working hypothesis one must assume that the - liver colls were slightly damaged by poison absorbed from the bowel during Ihe dry weather. They were further intensely damaged by the dnmming'-baok of bilo through blockage of bile-ducts.

PR EYENTTYE MEASUR ES Advice regarding pi'evontion of liver-damage with our present knowledge is impossible, hut probably if green ford were available- during the dry summer it would help considerably. Such a supply of green feed, however, would be almost impossible for most fanners to obtain without irrigation. Control of feed when conditions were known to he conducive to photosensitivity would certainly a.ssist. This was seen in several eases where owners had kept paddocks eaten down with cattle. Should climatic conditions recur within the next few years owners should at once close up the majority of paddocks and heavily -.stock a few to prevent excessive growth. As an alternative,. and where possible, the mower could- he kept going to level feed off. One- other practice which was adopted successfully on one farm in the Manawatu was- to put. out hay-racks for sheep in a small paddock and keep the animals entirely on hay and water during the first flush. They can then be slowly broken in to green feed. TREATMENT Stock must he watched carefully with it view to oaily mustering if swollen cars- appear- Driving must, he carried out slowly in. the cool of the day. Affected -sheep require to he placed in dark sheds at once and kept there, getting no green food for two or three days. They should be supplied with water and a light feed of hay. Badly burnt sheep should be slaughtered, for they never do well afterwards. All affected sheep should be given Epsom salts, Glauber salts, calomel, or other purgative to stimulate the bowel and liver. Faces may he treated with a black ointment or Stockholm tar, so as to cover the- skin with a black pigment to keep off light. Sheep kept in -sheds should first of all he let out at night for a few hours’ grazing, and then let -out in. the daytime, hut, with, the shed left open so that if they still feel the sun they may return to the shed at will. S‘nc-h convalescent sheep should not he returned to a flush of grass or they may readily suffer a relapse.

SUMMARY Facial dermatitis is known in both North and South Islands. In the South it is believed to be due to a plant probabl ya. ispccics of Hypericum, while in the North, the condition occurs under definite climatic conditions.

Two factors operate in the latter ease—the liver damage, the true cause of which is unknown; and the other, absorption of a flourescent. material from the breakdown of chlorophyll, which sensitises the onpigmented skin to light. Prognosis is had in such eases, alleviation treatment being to give purgatives and to keep in the dark away from sunlight until they have recovered.

FEET)TNG DAIRY BY-PEODUCTS

MILK USES OUTLINED In feeding; rnilk (separated, skim and butter) to porkers and baconers, where the supply is limited, it should bo fed from the pre-weaning stage until about the end of the fifth month in as generous allowances per head as the supply permits, when a. -reason-, able] valuation of 4d might he given. No precise value can he placed on separated milk, since its value is economically dependent upon variant factors including costs of raw foodstuffs, initial cost- of wearier, price received, whether purchased or home produced, and several other considerations —the value could fall within the range of from 2d to 8d a gallon.

Another valuable dairy hy-produet is wliev, which can be fed mixed in with a balanced meal mixture, displacing the normal water, or directly by mean of a gutter or channel, running the length of the feeding house. It should he clearly understood that, unlike separated milk, it is for all practical purposes a starch food, since it is relatively poor in proteins, chiefly depending upon its sugar content for its nutritive value.

To the cheese-maker whey should he at the moment worth Id a- gallon, hut to purchase it as a. feeder it is notadvised to pay more than approximately 'pi on the place of consumption.

Whey is an efficient food for pigy, hut should not lie fed too liberally to pigs under 5 score live weight. Like all other milk products, it requires careful handling in the way of eteanliniPSS' if digestive complaints are to ho avoided. THE TAM WORTH PTO The sandy red colour of the Tamworth. pig is evidence of its descent I rom the old English breeds. The Tamworth is, in fact widely regarded ns the oldest pure breed in England. Its fame as a producer of lean bacon is historical.

Of all the, improved breeds the Tamworth existed longer in its natural state, depending eleoflv on itself for its food ; and it i-s probably to this that is duo its persistence of type wh'ch was so jealously safeguarded h.v iho early breeders, and Inter by herd bool; representation. The official description of the colour is “golden red.” The coat should lie abundant, straight and fine, and as free from black hairs as possible- The head should not he too long, face sl'ghtly dished, with the skull broad between the cars and the jowl light. Ears need to he rather largo, carried rigid and inclined slightly forward. A light, medium-length nock, pro-po-i'l ‘mint olv and evenly set on fine shoulders is looked for—though there should lie no narrowness of shoulder to indicate lack of heart and lung room. The chest should he wide and deep, back long and slightly arched transversely above the shoulders. Although a level hack is usually preferred a slight longitudinal arching of the hack is not objected to; indeed, it would not he far wrong to say that it. was characteristic of the breed. The skin of the Tamworth should lie flesh-coloured, free from coarseness. creases or black spots. The Lollv '.should he straight, flank full and well let down and the hams well developed and full to hock.

It lias boon computed by n largo number of leading curcrs that a long level-sided pig. with fine shoulders, small jowl and book of moderate width, will prodnee as much as 10 per cent, less of lard parts, and accordingly an increased ration of lean meat. Fat is worth only half as nin eh as lean. The Tam worth excels as a lean meat producer, and is therefore valuable for crossing with the fatter, shorter types, in both baron and pork production. Tam worths are good grazers and. provided the right strains are selected, are sufficiently prolific. Tt is essentially an open-air pig able to thrive on rough and scanty herbage, and a “good-doer" whether in a hot or cold climate-llEßß-TESTING. .POWERS OF THE DAIRY HOARD.

NEW REO F RATIONS. New regulations concerning .herdtesting came info force last, week throughout New Zealand. The Now Zealand Dairy Foard is given authority to. regulate and ront rol : fa) Tile conduct of group herd-test-ing. and. in particular, such methods of group herd-testing as have heretofore boon regulated and conirMled by the Dominion Group TTerd-tosting Federal ion (Tncorp.) ; and fh), The branding or marking of stock for the purpose of identifying permanently such stock as being of a standard of merit fixed under a group herd-testing system, and, in particular, the system of branding or marking of stock instituted and heretofore controlled by the federation.

For the purpose of such, regulation and control, the hoard may employ inspectors, computers, clerks, and other servants, and may enter into contracts with individuals and corporate bodies undertaking or' concerned in group herd testing. t Tho power conferred on the Direc-tor-General of the Department, of Agriculture by section 3 of the Stock Amendment Act, 1927. to register in the name of any incorporated society whoso object or otto of whose objects is the improvement of stock, one or more brands or marks as a standard mark or marks to be used on stock, being stock to which any system of group herd-testing applies or is associated. shall bo exercisable only with the prior approval of the hoard.