DISEASES OF SHEEP.

Globe, Volume XXIV, Issue 2721, 29 December 1882, Page 4

DISEASES OF SHEEP.

The following paper was read by Mr Keginald Foster at the Kaiapoi and Softon Farmers’ Club meetings of November last. At the request of the members it is now publishoL Now Zealand is proverbially a healthy country for stock ; at the same time we are by ho means free from diseases. Most of them are, however, within onr control, as they are mainly caused by neglect, injudicious feeding, and putting sheep on land which is unsuited to them. Any animals placed under conditions unnatural to them become liable to disease ; sheep are no exception to this rule. I propose to notice briefly the diseases to which our flocks are most liable. Not many years ago scab was the only disease in sheep to which any attention was paid, but we may now almost look upon it as a thing of the past. The official return of infected sheep for the 30th September last, shows that in the North Island of 3114 flocks numbering 3,883,047 sheep, 21 flocks numbering 29,814 sheep were infected with scab ; while in this island, of 3743 flocks numbering 8,307,163 sheep, 43 flocks numbering 245,080 sheep were infected with scab. The disease is now confined to a few localities, where the country is rough and difficult to muster. At the present rate of progress there is every reason to hope that in another two or three years New Zealand will have a clean certificate, and in the meantime there is very little probability of the disease being allowed to spread to the clean districts. There are two skin diseases which, from their similarity, have frequently been mistaken for scab. They are not contagious, and generally disappear of themselves. In these dis’eases there is no visible insect, which is always to be found in true scab with the aid of an ordinary magnifying glass. We have a worthy representative of scab in the sheep louse, which causes almost as large a loss of wool as the scab. It does not, however, affect the sheep's health so much as the latter; the scab burrows under the skin, but the louse is a surface skin parasite. It breeds very fast, the young maturing quickly, and it causes very great loss of wool, as the sheep infested with lice are constantly rubbing against the fences, which they damage considerably, besides leaving a considerable amount of their wool on the ground. This parasite has not been known in this country many years, but it has increased to such an extent as to render it necessary to legislate for its suppression. One has only to look at the ragged fleeces in the saleyards and at the fences of paddocks where sheep infested with lice are running, to see what a fearful waste of wool is going on constantly. It would be a difficult matter to estimate what the annual loss to the country from the ravages of these parasites amounts to, 3d per head on the 6,000,000 long-woolled and crossbred sheep in the country amounts to .£75,000, or deducting Id per head for the cost of dipping £50,000. This may be thought excessive, but when it is considered that a flock free from lice is the exception, and that these parasites are at work day and night, attacking both fat and lean sheep, causing constant irritation, to the detriment of the wool, and loss of condition and wool, there can be no doubt that the loss is very heavy. Of course a good many people dip, but the work is so imperfectly done that a large proportion of the sheep are found to be infested with lice in i the spring. I look upon dipping as one of the most necessary operations in sheep farming. It i is a well known fact that ticks leave sheep a few hours after they are shorn, presum- ■ ably because there is not wool to cover them. It will be found however that a considerable number of the ticks will have i taken up their abode on the lambs, and these having very tender skins are kept in a constant state of irritation. In the case of ewes and lambs very bad with ticks or lice, I would advocate dipping after shearing, and in any case the lambs should be dipped after weaning ; for adult sheep March is the best month. Ticks and lice attach their ova to the wool, close to the skin. Dipping cannot be effectual unless these ova are either destroyed or detached from the wool. Most of the compounds sold for dipping are used -with cold water, and they are generally effectual so far as killing the parasite goes, but it is questionable whether a cold dip will destroy or detach the ova. It is to this fault, and to the common practice of not giving the sheep sufficient time in the dip that I attribute many of the cases I see of dipped sheep showing lice a few weeks afterwards. Many who have had this experience use the dipping stuff at an increased strength. This is unnecessary, and is likely to cause a stain in the wool. What is wanted is more time in the dip, so as to allow the skin to be thoroughly saturated; then, if the sheep dry before rain comes on, there is a chance of the young parasite being poisoned as soon as it is hatched. If sheep are really bad, I would recommend a hot dip, or two cold dips, at an interval of a fortnight. Dipping should not be carried on later than four in the afternoon, as it is well to allow the sheep to dry a little before night. Footrot is only prevalent on moist, oozy land, and is caused by decaying vegetable matter getting between the claws of the foot when the horn is in a softened state by exposure to moisture. Sores are caused, from which matter exudes. It is undecided whether footrot is contagious, but there is very little doubt that this matter is poisonous, and that any sheep whose hoof is softened by exposure to wet, and overgrown, which causes an unequal bearing, and a consequent weakness round the coronet, will become footrotted if the foot comes in contact with it. The matter, however, does not appear to cause footrot where these conditions do not exist. Many cases have been known where footrotted sheep have been put with sound sheep on dry pasture, and the disease has entirely disappeared. In treating footrot, it is first of all necessary to pare the hoofs, cutting away the superfluous growth of horn and exposing the diseased part. The foot should then be dressed with arsenic, carbolic acid. Milestone, or in fact any of the reputed foot rot specifics. The sheep should, after dressing, be put on clean ground and be well kept. In paring it is better to use footrot scissors rather than a knife. The latter, unless very sharp, is apt to drag the hoof, which only aggravates the disease. Merinos are more liable to footrot than other breeds of sheep, probably because, being usually bred on stony and hilly country, their hoofs grow faster and are less accustomed to moisture than those of paddock sheep. The disease known as staggers is very prevalent among paddock sheep at the latter end of dry summers. It is not often that sheep die from this disease, but its effects are very serious. Sheep badly affected cannot be moved, as on the approach of dog or man they are suddenly seized with a fit and tumble down in all directions. This disease is usually attributed to the effects of ergot in the seed stalk of the grass. Many practical men, however, are of the opinion that it is caused by indigestion, and I am disposed to agree with them for the following reasons:—lf a sheep that has died from staggers bo opened, a hard ball of undigeste i seed stalks will be found in the stomach, and it is well known that any disorder of the stomach immediately affects the brain. If the sheep are moved on to native pasture they will recover in two or three days, but if put back on the English grass they become affected again just as soon. If the pasture has a fair admixture of cocksfoot grass, which being a deep-rooted grass always throws green shoots in summer, and, moreover, is not so liable to run to stalk on light land as rye-grass, sheep will | rarely bo affected with staggers. The disease is always worst in a dry summer.

These facts seem to show that staggers - is caused by the sheep eating a quantity of indigestible seed stalks, and that almost immediately the cause is removed by assisting the digestion with a change of food the malady disappears. It is thought by some that the grub in the head—(Estrus ovis—is the cause of much sickness and mortality in sheep. My own opinion is that though doubtless these grubs in making their way up the nostrils to the frontal sinuses and the matured grub in making its exit cause intense irritation, they are no real detriment to the sheep. lam led to this conclusion because having examined a great number of the heads of all classes of sheep, I find just as many grubs in the heads of fat wethers as any other sheep, and I have not noticed that the sheep with grubs showed any symptoms of ailing. Our flocks have hitherto been remarkably free from internal diseases, such as catarrh and fluke, but within the last few years a very troublesome disease has appeared in young stock; it is known in England as “ husk ” or “ hoose/’ and is caused by thread-like worms in the bronchial tubes. There is but little doubt that the mortality among hoggets, usually put down to scouring, that owners have suffered for several years past, has been aaused by these parasites. The disease appears in the autumn, and the symptoms are first a dry cough, followed by ceasing to feed, separation from the flock, and ending with diarrhoea It is most important that this disease should be promptly dealt with, and therefore those who have suffered from it in previous years should be on the look out for the first symptoms in their weaners. The best known remedy is the inhalation of the fumes of sulphur or carbolic acid, which is administered by putting the ■heep in a close stable or shed, and burning the sulphur on a coal fire, the sheep being kept in about ten minutes. This should be repeated in three or four days, and the sheep should be put on the best feed. If the worms are allowed to become deepseated in the lungs it is doubtful whether any remedy can be depended on to dislodge them j but a great deal may be done in the way of chocking the disease, and if the sheep can be got safely over the winter the spring grass will enable them—or at any rate a large proportion of them —to throw the disease off. There are various other parasitic worms which attack sheep internally, but, so far as I am aware, our sheep are free from them. Eock salt is the most valuable preventive for all internal parasitic diseases, besides acting as a tonic. Paddock sheep should never be without it, and it should always be in the lambing paddock, so that the lambs should acquire a taste for it from the very first, and so be in a great measure protected from parasitic diseases. The disease called braxy has caused heavy losses in sheep on turnips during the last two or three seasons. The superabundance of watery food brings this disease on, and death takes place in a few hours. It may to a great extent be avoided by giving the sheep hay with the turnips. It will probably be found that quickly grown watery turnips are the most likely to cause this disease. Our lambing ewes are not, as a rule, very subject to disease. At the same time, they should be carefully watched, especially in the case of merino eves put for the first time to long woollcd rams. , Parturient fever is perhaps the most prevalent disease, and as it is highly contagious, the hands should be anointed with carbolic oil before touching the ewe. The oil not only acts as a disinfectant but is very beneficial to the owe. Many a valuable ewe has been lost through neglect of this precaution A small bottle of this oil is easily carried. Another disease, about which little appears to be known, is prevalent among ewes bearing twin lambs. The ewe separates from the flock some two or three weeks before lambing, and, in a few days, lies down and dies. In almost all cases the ewe will have fine twin lambs in her and be in good condition herself; it seems as if the feed/which is sufficient to sustain the ewe bearing one lamb, is not sufficient, for the ewe bearing twins. Fever is caused ; which first kills the lambs, and then the ewe succumbs. These are the principal diseases from which our flocks suffer, and with ordinary precautions and attention they may, to a great extent, be avoided. In dealing with diseases, promptness, both in the treatment and in the removal of its cause, is essential. If these points are observed, diseases in the flocks of New Zealand should be reduced to a minimum. Since writing the above, I have found worms in the large intestine of a hogget. The sheep had the appearance of being affected with long worms, excepting that it had no cough. The owner of scouring hoggets, therefore, will do well to make sure as to what is the cause of the scour before using any remedy. The presence of worms is generally indicated by the slimy and loose state of the excrement, which change of feed will not cure. Lungworms cause a dry husky cough. Intestinal worms have the effect of stimulating the appetite for a time. In both cases the sheep waste and become emaciated. Turpentine and linseed oil, with plenty of rock salt, is the remedy for these worms. •