FOOTROT

Press, Volume LXXII, Issue 21808, 13 June 1936, Page 10

FOOTROT

A DESTRUCTIVE DISEASE METHODS OF PREVENTION AND CURE (Published under auspices Canterbury Agricultural College.) Footrot is a specific and contagious disease of the leet in sneep. In any country footrot stands as one of the most serious diseases tiiut exist among sheep. However, it is a disease which is amenable to treatment, and can be prevented. If sheep owners would only appreciate the contagious nature of the disease and adopt effectual measures to prevent its introduction into a flock, or even combat it promptly when introduced, they would be handsomely repaid for their trouble. Experiments have demonstrated the infective nature of the virus or poison of the disease by the application of the infected material from diseased sheep to the feet of healthy sheep, and also by the association of healthy sheep with diseased animals. The disease may affect sheep on dry or wet country if the infective agent be present. A favourite haeffat of the organism is wet or marshy places, or where there is an accumuiation of excreta in a damp state, such as is often seen in dirty sheep yards. When one case of the disease appears in such a place it rapidly spreads through the flock if preventive measures are not adopted. The disease is rare in dry hilly districts. Contagious footrot is primarily a disease affecting the soft structures of the foot. Any diseased condition of the horn itself is secondary, and is brought about by the separation of the soft from the horny structures through the agency of micro-organisms and the fluids eruded. The disease spreads from sheep to sheep, causing much lameness, loss of flesh, a..d may even cause death from emaciation. When the disease appears in a flock of in-lamb ewes, it is a still more serious matter, as carrying out proper treatment is not without danger. In such instances

the disease may persist until the lambing season commences, the disease rapidly spreading to the qpw-born lambs. Apart from the adverse influence that wet seasons and damp pastures have upon the horny structure of the feet, grit and dirt may' work ‘ their way into the cleft of the foot and produce a wound. If the soil be contaminated with the virus that produces footrot, the disease will soon appear among the flock. However, it can attack sheep with apparently firm horn and well trimmed feet. Experimentally the exudation and debris from an infected foot smeared round the corneal tissue of a healthy sheep will cause the disease. The virulence of the organism becomes increased by its sojourn in the foot, thus accounting for the rapidity with whic’ the malady spreads after a single case is established, thus explaining the contagious nature of the affection. The virus has not yet been isolated, Research workers usually find in the lesions the bacillus necrosis, but it is believed to pe secondary to the primary cause. Symptoms Lameness first attracts attention, and it varies in degree according to the state of the disease; on the examination of the foot or feet affected, a small, moist, unhealthy-looking spotlike sore will generally be found between the toes. There is little or no appreciable swelling of the coronet at this stage. The disease rapidly extends under the horny box, and if a little pressure be brought to bear on the inside of the foot a slight dirty foetid discharge will be observed ooz-

ing from the edge of the horn round the ulcerated spot. The disease progresses from above downwards between the sensitive structures of the horn and' hoof. When the horn is pared away the diseased parts are found bathed in the foetid discharge and the greater portion of the foot may be involved. In very bad cases the disease extends from its primary seat to the more important tissues of the foot, injuring the ligaments and tendons, and even the bones. In these severe cases the foot may be greatly swollen, very tender and hot. The animal is in great pain when weight is placed on the limb. Abscesses form in the soft tissues of the foot and burst outwardly round the coronet, leaving angry discharging wounds. One foot is usually affected at the outset, but the disease frequently appears in two, three, or even all four feet. Sheep may be seen feeding on their knees, or lying down feeding on the grass round them. When the lesions are associated with much pain, and when three or four feet are affected, the sheep rapidly lose flesh, and diarrhoea may supervene. During warm, muggy weather the condition is aggravated, and the foetid discharge may attract flies, and maggot subsequently develop in the wounds. An affected animal may become fly-blown on every part of its fleece that has come in contact with the discharges.

Prevention It has often been said that a shepherd has no right to have footrot in his flock. Providing ordinary care is observed the disease should at least not get beyond control. The best plan to prevent the introduction of the disease is to avoid bringing suspected sheep on to clean pastures. Therefore in a season similar to the present, attention must especially be directed to fresh arrivals. The following are the cardinal points for preventing the disease appearing:— (1) Periodical inspection, examining and trimming of overgrown feet is a practice to be recommended, and upon the slightest indication of disease affecting the skin, the affected sheep should be isolated and treated and the remainder put through a bath containing one of the preparations given below. (2) In the case of sheep bought in a saleyard or taken to a saleyard and brought back, they should, wherever possible, be isolated and the feet of each sheep examined. Isolation and close supervision should be continued for four weeks. The disease can appear 21 days after infection, 21 days being the longest known incubation period of the virus. As a precautionary measure tne sheep can be put through a foot bath containing one cf the preparations recommended below, on three occasions during the first 12 days and ~~4.0re mixing with the other stock. (3) The shepherd should always wash and disinfect his hands after the examination of recently acquired stock before attending to any of the old stock, and the same remarks apply after the examination of any individual suspected cases. (•I) It is advisable to afford contaminated pastures a rest until a winter's frosts have intervened. (5) Attention must be given tb the sheep yards, which should , be

(1> Examination of the entire flock, separation of the healthy from the diseased. Healthy sheep should every third day be put through a bath, and this can be advantageo-sly continued for 14 days after the last case has been detected. (2) Sometimes sheep may apparently recover from footrot without treatment, and the disease again break out after an interval of 21 days. Treatment, however is necessary to avoid loss, and prompt measures materially assist in arresting the spread of the disease. The earlier the cases are recognised and treated, the more readily and certainly will they yield to treatment. Ail detached horn- from those gravely affected should be freely and carefully removed, so as to expose the affected sensitive structures. Skill and patience must be exercised in paring away the horn. It is imperative to expose all the diseased tissue, and the more advanced and neglected the case the greater will be the labour required. All granulations or fungoid growths should be removed with the knife or secateurs. (3) It is important to remember that all removed particles of horn or other tissue should be destroyed by fire, as such material may serve as a means of further spreading the disease. (4) When the cutting and paring has been deep, the structures at the foot require constant attention and repeated treatment by dressing with a dry powder, composed of equal parts of boracic acid and calcium hydrate. Use of Footbath Some years ago it was noticed that the ordinary process of dipping sheep tiff* curaave effect. Arguing from this it appeared probable that beneficial results would follow the slow walking of sheep through a solution of various remedies just deep enough to cover the hoof. 6 in T TW-? r H^ S f h -K ,I j nistr £ of A&riculture hlthH°li8 d l> Str ? b V tea d 0 wood en foot baths 16 feet long and eight inches wide at the bottom, 10 inches Icrossthe {??' inches deep, each accompanled lcwt of bluestone (copper sulber te of corres P° n ding number of sheep farmers. The' instruchrnLh ere walk sheep through a 5 ,per cent, solution every tb^f e j 0r fo, i r da ys. after having cleaned and dressed the hoofs in the case of

a bad attack. This was found to b« most effective. Copper sulphate to be 98 per cent. pure. The following are equally effectual: — (a) Formalin 75 per cent., water 25 per cent. (b) Formalin 6 pints, copper sulphate 4oz, water 2 pints. Dissolve copper sulphate in water and add formalin. Ihe above makes one gallon of solution. (c) Commercial sulphuric acid, 10 per cent, solution. Two pints of sulphuric acid to one gallon of water. Care must be taken in the mixing, and only earthenware vessels can be used. Sulphuric acid attacks all metals with the exception of lead. The acid must be added slowly to the water, keeping the solution well stirred. Much heat is involved, and the solution is very destructive to garments. Summary of directions for using the foot bath:— (a) Bath of wood 16 feet long, eight inches wide in the bottom, 10 inches across the top, seven inches deep. The bottom provided with cross pieces one inch wide, six inches apart to prevent slipping. Hurdles can be used for side fences, the hurdles sloping outwards so as to admit the sheep walking easily through. (b) The bath to be filled to a depth of three inches. The sheep to be walked through slowly. (c) If copper sulphate is used, preferably in the powdered state, large crystals take a long time to dissolve. (d) Badly affected sheep to have their feet pared. (e) The sheep to be turned on to a dry paddock after walking through the bath, (f) Sheep with long wool must be put thorugn quietly, or otherwise the solution used discolours the wool. (g) The foot bath should not be erected in the sheep yards, but preferably in the corner of a paddock. Sheep with footrot should not be brought into sheep yards, as the yards become infected with the virus and are often the cause of the disease reappearing.

The annual South Island Sheep D°<S trials championship meeting will be held at Mossburn, Southland, commencing next, Tuesday. June 16, en® extending over the following three days. The trial ground is 13 mile* from Lumsden, and about 50 from Gore or Invercargill.