BLOOD POISONING (MALIGNANT ŒDEMA) IN SHEEP AFTER SHEARING AND LAMBS AFTER DOCKING.

Otago Witness, Issue 2490, 4 December 1901, Page 9

BLOOD POISONING (MA LIGNAN T ŒDEMA) IN SHEEP AFTER SHEARING AND LAMBS AFTER DOCKING.

By J. A. Gilrtjth, M.R.aV.S., Chief Veterinarian.

(Leaflet No. 58). This disease, which occurs during the gelations of shearing sheep and of castrating and docking lambs, is the cause of ;onsiderable loss annually to sheep-breeders in several districts of the colony. In 1893 a leaflet was -issued dealing with the disease and preventive measures to be adopted. Where any recommendations have been followed there has been little or no trouble, but it ■* aa apparent that many owners have not availed themselves of the services of the department by advising us in time, and losses have been considerable in consequence. Generally the first thing- that draws the owner's attention seriously to the condition of his flock is the discovery, in from 36 to 48 hours after docking or shearing, of a few dead sheep lying in various parts of the paddocks. Next morning he finds a lew more dead, and so on for three or four days, .when, as a rule, the mortality ceases. Symptoms. — On account of the gregarious lhabits of the sheep, an ailing animal, unless exhibiting very violent symptoms, is easily overlooked. In the early stages of this disease the animal seems listless, disinclined^ to move about, and, if the sun is chining strongly, prefers to lie in the shade. If forced to move, .he hind legs are drawn forward with a peculiar stiff, dragging motion, a« if there were no joints. There are slight muscular tremors all over the body, which (become spasmodic as the disease progresses. M the flock be driven about much, the dieeased animal coon shows sign ol great faJtigue, ultimately dropping to the ground <#horoughly exhausted. The breathing is fast and painfulj being maintained more by a series of spasmodic jerks than by any tegular aqt t The pulse is fluiok and w«akjL

the temperature is very high, registering 106deg to 108deg Fahr. , showing acute fever ; the eyes close, and the whole face is expressive }f great pain. Gradually the spasms cease, and coma sets in, resulting in death. The scrotum (bag) and surrounding skin right along the floor of the abdomen and between the hind legs become swollen and black. This gangrenous tissue, when present before death, can be peeled off without pain to the animal.

On popt-mortem examination various 'ondilions are met with. The animals are generally found to be amongst the best of the flock, and in fairly good condition. The scrotal and perinasal regions in lambs (between hind legs and below tail) are always, or almost always, gangrenous, this condition extending along to the floor of the chest, and sometimes implicating the tail. Many of the muscle?, generally these of the shoulders, haunches, and loins, are dark in colour and infiltrated with a black, watery fluid. The intestines are generally healthy, though sometimes the peritonaeum is inflamed. The spleen and liver are in the upual condition after death due to febrile disturbance. In the chest, either the pleura (coverings of the lungs) or pericardium (covering of the heart) are often inflamed, with occasionally a fibrinous exudation, causing the surfaces to adhere.

The following description, by Mr Reaves, Government Veterinarian, of an outbreak in rficep after shearing, i^ fairly typical: — "At the e-nd of December I received in structions to visit a station in the Mackenzie Country, where serious mortality was occurring among sheep immediately after shearing. On arrival T found that, owing to the large number of deaths, shearing had been entirely suspended. About 4000 sheep had been thorn, of which some 300 had died. - was informed that the affected animals exhibited, the . first symptoms in from 24- to 48 hours after being shorn, and usually lingered two or three days before dying. The first noticeable symptom was' an oedema tons, rapidly spreading swelling, always in conjunction with and iv proximity to a wound from the shears. It was noticed that if this occurred on the lower portion of a limb the animal frequently recovered, whereas if high up on the limb or on the under part of the body death was an invariable result. When these csdematous swellings were incised during life a clear serous fluid exuded, but after death this fluid was blood-stained. The swellings occasionally ruptured during life, discharging a portion, if not all. of the contained fluid, this being often, followed by recovery. The sheep appeared dull, off feed, and semi-co-.natose. The same trouble had occurred at shearing time for at least five years past, and in the preceding three years the mortality had been as- heavy as was tlie case this jreai\~ Before commencing shearing the whole of the shed had been thoroughly washed out with a strong solution of Jeyes's fluid, the characteristic odour of which was obtrusively apparent on entering the building.

'"Previous to shearing the whole of the cheep had been remarkably healthy, the total loss during the past year being only 2 per cent., these dying from shortage of feed and exposure during the winter. Everything pointed to contamination of either the shed or yards (probably the latter) being responsible for the trouble. On this assumption I obtained four unshorn wethers, and inoculated each in the thigh with 5 c.c. of water, in which earth from the surface jf the yards had been stirred. The bulk of the solid matter was allowed to precipitate, and the muddy-coloured fluid injected. Next (fay all four were showing various degrees of lameness, with heat and swelling at the seat of inoculation. Some three days after one of these died, showing similar symptoms to the sheep infected after shearing. The remainder, after being sick some days, recovered. As a result of the investigation, I strongly advised the owner to build an entirely new shed and yards at a distance from those then in use, a course which he expressed himself determined to follow. The remander of his sheep were shorn at a neighbour's shed, no further trouble occurring."

Cause-. — In my annual report for 1900 I havfe demonstrated the cause of this bloodpoisoning to be a microbe known as the malignant oedema bacillus (Vibrion Septique of Pasteur). This organism, which is found in many dirty yards, swampy soils, etc., on gaining entrance to the system of almost any animal by means of a wound, rapidly increases in numbers, producing gangrene or death of the part affected first, and ultimately the death of the animal.

Curative. Treatment. — This is practically useless, being even in the human patient, where every care can. be taken, and expense is of no moment, rarely successful. Preventive measures can be adopted, however, and here aiuch that is beneficial may, ba accomplished with the exercise of a little care and trouble.

Preventive Measures. — Being- organisms capable of producing spores (seeds), the bacilli have great resisting power, and in all probability may remain for year 3in the soil. The practice of leaving carcases of animals dead of this disease lying on the paddocks to rot and be torn „0 pieces by hawks is very pernicious 1 . As a result fresh centres of infection are formed through the absorption of the bacilli by the earth, and probably the disease is spread to considerable distances by the carrion-hawks, directly, through dropping portions of the flesh, and indirectly, possibly, through the bacilli passing out of the intestinal canal of the hawk, uninjured, among the faeces. One means of prevention strongly indicated, therefore, is the destruction of the carcases of animals which have succumbed to this disease, by efficient burial or by fire. It would appear that in most instances the contagion is present in the yards or surroundings of the woolshed, and is consequently extremely difficult to get rid of. In order to do so it would be necessary to employ some means such as the following :- Remove the surfacesoil of the yards and surroundings to a depth of about 6in, and place in a heap, where it should be thoroughly mixed with quick-lime. Then saturate the fresh surface exposed with a strong solution of crude carbolic acid, or of some NON-poisonous disinfectant sheep-dip, that which remains after the usual sheep-dipping operations, where such a dip is employed, being adnJr. lably suited for such' a purpose. It would be advisable, also, to thoroughly clean the floors and walls of the sheds, and apply strong hot lime-wash, with which should be mixed come powerful disinfectant, such ■as crude carbolic acid, in the proportion of 1 in 50. Along with the above precautionary measures it is absolutely necessary to adopt some means of preventing the germs from gaining entrance into the flesh-cuts made by the shears, or the docking and castrating-kniie. In the shearing-shed it should be imperative that the shearer on juaJouui A gut* especially iv the region of

the breast, belly, or legs, should immediately a Pplj r some tar or other antiseptic to the •wound. This practice is in force in several sheds with distinct advantage, but in many no precautions whatever are taken. For lambs at docking and castrating time I recommended, seven years ago, the application of carbolised oil (1-12) to the wounds on the scrotum and tail before releasing the animal after the operation, and where this has been acted upon the benefits have been marked. Docking and tailing krmes should for preference be boiled before use.

In several instances this disease ha? been prevented from occurring in lambs through castrating in temporary yard» made of movable hurdles &itualed in a fresh paddock, but I have known cases where this was not followed by the success anticipated. The reason was to be found in the adjacent swamp', where probably in former years animals had died of the same disease, and the carcases being left to rot, the water had gradually disseminated the germs throughout the swampy area. The lambs, feeling weak from loss of blood, had taken to the shelter of the long tussocky grass growing in these swampy areas, and the wounds coming in contact wnh the infected ground had become contaminated. This demonstrates the necessity for using antiseptic applications even when tpmporary yards are employed, and for keeping sheep and lambs after the operation in a paddock free from swampy patches.