The Journal of Agriculture.

New Zealand Journal of Agriculture, Volume XIII, Issue 3, 20 September 1916, Page 173

The Journal of Agriculture.

WELLIN NEW ZEALAND. 20TH SEPTEMBER,* IQI6.

NOTES FOR SHEEP-FARMERS.

C. J. REAKES,

D.V.Sc., M.R.C.V.S., Director of the Live-stock Division.

WHILE New Zealand is remarkably free from sheep-diseases of a contagious nature, sheepowners still have to 'contend with trouble in ’ the ’I shape of sickness and mortality

due to other causes. ' Most, of this is the- result of sheep -and lambs living under what are ' really .conditions too, good for their physical well-being, nature having ’ so fashioned ' the “system ; of the sheep as to render it an animal. capable of remaining strong and healthy under adverse climatic and feeding ’ conditions, such as are brought about 'by cold winters with accompanying shortness of feed, necessitating free and -constant , movement in order to obtain the nourishment necessary for the proper maintenance of health. A good illustration of this is furnished by the fact that

this season, as has been the case regularly in previous years, such troubles as ante-partum paralysis of ewes and ante-partum extrusion of the vagina (described in Veterinary Bulletin No. 15, by Dr. Gilruth, issued by the Department) have taken their annual toll in districts where ewes have been so “ well done by ” during the winter as to come towards their lambing in too high condition; whereas in the higher land of the South Island, with its more inclement climate, these troubles are seldom if ever heard of.

It is all a question of management. Farmers naturally keep sheep for the purpose of making money out of them, and the most successful man is he who realizes how far he can go in the direction of doing his ewes well without overstepping the danger-mark and allowing them to pile on fat to too great an extent prior to lambing. It must be realized that a ewe which is carrying too much fat is physically weaker in every way and less likely to rear a profitable lamb than is one which is simply in good healthy condition. It is right enough to give -the ewes plenty of good feed when they are suckling their lambs, but it is risky to do them too well during the last two months before lambing. . I have said or written all this before, but there is evident good reason for repeating it.

ACUTE CONGESTION OF THE ' KIDNEYS IN LAMBS.

Following on the above general remarks regarding ewe troubles’ attention must be called to the mortality which occurs every season among lambs chiefly in the North Island, where feeding and climatic conditions are most kindly to the ewes and lambs. This affection is purely one brought about by overnutrition. It is almost invariably those single lambs in the highest and best . condition that are affected. Twins, having to share the milk of their dam, run less risk of overnutrition and usually escape trouble. Dr. Gilruth, to whom New Zealand owes much for his investigation work in connection with sheep-diseases, wrote very fully upon this trouble in the annual report of the Department for 1907. The sound opinions he formed then have not been shaken by later experience, and the extracts from his report which follow, and which comprise the facts of the matter from the farmer's point of view, are well worthy of reproduction [at the present . time. His opinions were as follows: —

As regards symptoms, there are none of a premonitory nature. Usually the lamb, strong in build, fat in condition, usually a “ single ” lamb and about a month old, is found dead, lying in a more or less natural attitude. Death generally occurs suddenly often while playing. Occasionally some form of giddiness may be observed for a few minutes before death, but nothing more definite.

.If the internal organs be examined immediately after death they will appear practically normal to the casual observer. There is a good deal of fat beneath the skin and in the abdominal cavity. The functions of the rumen (paunch) have just begun to be employed, as is evidenced by the fact of 'grass being present in it. The age is constantly from about four to eight weeks. The fourth stomach contains curdled milk, which, although only to be expected, seeing that the animal will have fed only recently, is frequently and erroneously deemed by the shepherd to be the cause of death. Almost with equal constancy may be found among the contents of the fourth stomach a loose ball of wool, or of wool and grass, to the presence of which death is almost generally attributed. As such a collection of wool is almost invariably found in any lamb’s stomach, it having gradually accumulated through strands of wool being swallowed accidentally in the process of sucking the mother’s teats, and as it never, in my experience, is in such a situation as to cause interruption to the passage of ingesta onwards from the. stomach, and as there is never any evidence whatever of gastritis, its presence is totally without significance from a pathogenic point of view.

The kidneys are the only constant seat of disease, and in a casual post-mortem examination they are easily overlooked. They are bulky, dark-coloured, and are often so soft and extremely pulpy that they cannot be removed in a complete condition, and frequently have the capsule enclosing them ruptured in handling, and only a dark pulpy mass may be secured. The kidneys generally appear enlarged. On removing the capsule of the kidney the tissue beneath has almost the appearance of a blood-clot, due to congestion and the enormous haemorrhage which has occurred in the substance of the organ. The liver is also generally congested. The heart is frequently distended, and the pericardium (the membrane enclosing the heart) usually contains clear gelatinous fluid, varying in quantity from 2 to 4 fluid ounces.

It is difficult to state exactly what is the exciting cause of this congestion of the kidneys and liver, but the predisposing causes are very evident. They are as follows : The age of the animal— is, the time when the milk of the mother has begun to be supplemented by herbage rich and plentiful supply of mother's milk, the absence of another lamb to diminish the, excessive supply of mother’s milk, and good .pasture, favouring the production of this rich and plentiful supply of milk. In other words, all that tends to induce a plethoric condition in the lamb at the age of from four to eight weeks, before, it has begun to take exercise far afield from the mother, predisposes to this disease. That this is so is proved by the fact that the best and surest preventive measure to adopt is the docking of the tail when the lamb is about three weeks old. After castration the disease rarely or never appears in ram lambs, whereas in ewe lambs, especially those docked when about a week or ten days old, it may appear later. This means simply that ample bleeding, by reducing the plethoric condition of the animal, removes the primary predisposing cause of this disease. ■ z .

i Obviously there is no treatment applicable as a curative measure. Prevention, however, is simple, consisting as it does of docking before the danger period of life occurs. In the case of ewe lambs which it is necessary to dock early, the tails should be left sufficiently long to permit of another joint being removed if found advisable later on, to reduce condition by bleeding, and so prevent further losses by the disease.

In spite of this information, published nine years since, there is still reason to believe that the idea that “ wool balls ” in the fourth stomach, the true digestive stomach, are the cause of death still exists in the minds of some farmers. But that idea is- absolutely fallacious. In 1912 arrangements were made for Inspectors at meatexport works to examine a number of the fourth stomachs of fat healthy lambs killed for export. Of 4,043 examined, 792, or 19-58 per cent., were found to contain “ wool balls/'

BLOOD-POISONING IN SHEEP AFTER SHEARING AND LAMBS AFTER DOCKING.

Blood-poisoning in sheep and lambs now causes a mortality very small in comparison with what occurred regularly until a few years since, previous to which the annual death-rate caused by it was far too heavy. A bulletin on the subject (Leaflets for Farmers, No. 58) was written by Dr. Gilruth in 1909, and in this a very full description of these troubles is given. Copies are available on application to the Department in Wellington or to any Inspector of Stock. As is shown in this • leaflet, the condition of blood-poisoning is set up through a particular micro-organism (the bacillus of malignant oedema) gaining, entrance. into the system of the sheep °or the lamb through wounds or abrasions accidently occurring during shearing, or through the wounds made in the operations of cutting and tailing. In nearly every case investigated it has been shown that the animals became infected through dust or dirt from contaminated sheep-yards or their immediate surroundings coming in contact with the freshly inflicted wounds. Lambs are now usually cut and tailed in . temporary yards formed by hurdles in paddocks, and this practice has given successful results from ' the point of view of prevention. But it alone is not always sufficient. .In one instance which came under my personal notice there was no reason to believe that the yards used... were infected, but the human’ • element failed badly. . The instrument used was a knife which the operator (whose ideas of cleanliness were far from being up to date) was in the • habit of making use of for all sorts of purposes, including the skinning of , dead sheep, and it was evident that he took no pains .to keep it properly clean. A number of the lambs died of bloodpoisoning within forty-eight- hours, and a very careful 1 and thorough •investigation made on the spot failed to show any other source .of infection than the dirty knife.

It must be remembered that the particular micro-organism which causes this form of blood-poisoning is one that reproduces itself by spores (which , may be likened to seeds), and that these spores can

retain their vitality outside the animal body, especially in the soil, or in the dirt which . accumulates in the handle-socket of a dirty, knife, for a long period. A ground-surface badly fouled by dung, or a knife fouled by use on dead sheep and not. properly cleansed afterwards, is always dangerous from the point of view of bloodpoisoning. The majority of sheep-yards are - evidently not contaminated by malignant oedema, since no trouble caused by this disease occurs at shearing-time among sheep held in them; but whenever sheep die of blood-poisoning after shearing ■ radical steps should be taken to prevent future trouble. One of two things must be done :— ■

(1.) The provision of new yards on clean ground. As this necessitates also the erection of a shearing-shed, it means the incurring of considerable expense. At the same time there are some shearing-sheds in the Dominion which could with advantage be abolished and replaced by better and more up-to-date buildings.

(2.) The removal of the whole of the surface soil of the yards to a depth of at. least 6 in., and preferably 1 ft. Saturating the newly exposed surface with a solution of non-poisonous dip of a strength not less than 5 per cent., and after this has dried giving a heavy coating of lime. After applying the lime, the replacing of the removed soil by clean earth taken, in flat country, from well below the surface (but never from land inclined to be swampy), or from a cut into a hillside whenever possible.

Lambs should never be cut and tailed in sheep-yards, as, eVen if the organism of malignant oedema be absent, they are more susceptible' to the effects of the contamination of newly inflicted wounds by dirt than are older sheep.

Where outbreaks of this disease have occurred at shearing-time it has been at times noted that contamination of the shearing-shed itself has been suspected by 'the owners as being responsible. Our usual experience,. however, is that the source of the trouble lies in the yards; though some of the sheds, together with the groundsurface below their . gratings, have certainly been in a very dirty, conditionone which, on general principles of reasonable sanitation, should not exist.

. The symptoms of blood-poisoning are very pronounced, and are not likely to be mistaken for anything else. They usually appear within from twenty-four to forty-eight hours after shearing or docking and tailing. The most characteristic feature -is a .wellmarked swelling, which quickly becomes dark-coloured -r- in fact, almost black —and gangrenous. In the earlier stages the animal moves stiffly when forced to movement, gradually becomes more and

more , dull and listless, is off feed, and is obviously in a very bad way. Marked lameness is noted in the early stages when infection gains entrance through wounds in the leg after shearing, In grown sheep recovery-sometimes takes place, especially if the point of infection is situated in the lower portion of a leg. Whatever mortality occurs is all over within four or five days at the outside in the case of sheep, and usually within two days with lambs.

Attempts at curative treatment are of practically no value. Prevention, which can be secured by the possession of the necessary plain knowledge and the putting of it into practice, is the one thing necessary for the avoidance of loss through this particular manifestation of blood-poisoning.