MORTALITY AMONG SHEEP WHEN DIPPED.

Shannon News, 4 December 1928, Page 4

MORTALITY AMONG SHEEP WHEN DIPPED.

(Reprinted from Agricultural J ournal—Report by E. J. Lukey B.V.Sc. )

Reports of considerable mortality occurring among sheep after dipping were received during last season by the Christchurch office of the Department of Agriculture, covering the whole of the Canterbury district, and it is understood that mortality from the, samb cause occurred also more or less in other parts of New Zealand. Investigations into the deaths were made by officers of the Department, also in a number of cases by private veterinary surgeons either on behalf of the farmer himself or the firms handling the particular dip. These investigations in every ease showed that the deaths were due to broncho-pneumonia. brought about by tho dip-fluid entering the lungs. In every case inquired into the history showed that the deaths took place between the second and fifth days after dipping. It was also a very noticeable fact that the mortality seemed to be confined more to rams and lambs, and that in practically every osse it was with the first dipping of the season and in the first mob dipped that the deaths had occurred; furthermore, two farmers assured me that it was the very first lambs in the dip that had died. The mortality was greatest during January and February, the two hottest and driest months of the year. The affected sheep bore a very dejected appearance, standing apart; from the remainder of the flock, breathing heavily, and with their heads down. In seme cases there was a blbod-tinged frothy discharge from the nostrils, and in others slight salivation. Several post-mortem examinations were made of carcases of sheep that had died, and other sihecp showing symptoms were slaughtered and examined. The abdominal organs appeared normal to the" naked eye, except in a few cases where the fourth stomach showed distinct patches of acute inflammation, the gullet in these cases also showing similar lesions. The lungs in all cases were in a hepatised condition —that is, a condition resembling a liver. The mucous membrane lining the trachea and bronchial tubes (airpassages) were acutely congested, and in many cases the lungs were of a purple-black colour. There was a frothy ldood-tingcd exudate in the trachea. In several cases there was an acute in flamriiation of the larynx, giving indication of haying been caused by stome strong irritant. The whole picture was one of broncho-pneumonia. Two Causes.

Pneumonia may follow dipping in two Ways: First, merely as a result of chill and loss of vitality following .dipping under unsuitable conditions, of which common instances are shown when lambs are clipped late in the afternoon and are not dry at nightfall: In. such case, it after sundown the temperature of the air falls quickly, and especially 1 if there is a strong cold wind, there is a great probability that a number of lambs will succumb to pneumonia. The same risk attaches to dipping adult sheep, but in-a lesser degree. The second cause of pneumonia, and by far the more common of the two, is tho accidental aspiration of the dipping-fluid into the. lungs of the sheep. This is known as traumatic pneumonia, and was the condition met with-during our investigations.

Dips Not to Blame. But why was the mortality greater this year than in other years? This is a natural question which the farmer should and did ask. In some eases the sheep had been yarded overnight; in others they were in a paddock adjoining the dip; and, again, others had been driven through several paddocks and even distances along the road. Was tho dip at fault? Many, farmers thought the strength of the dip had been altered; but against this; as far as we know, every known liquid or paste dip on the market was reported as having been used. One farmer using a particular dip which will be called “A” bad losses. He. then changed the dip and used what may be termed “B" with good results. Av little farther away another farmer usod “B” dip and had losses, so tried “A" with good results. Again, in one case where eighty lambs were dipped, twenty-eight died, although the following day one thousand sheep were put' through the same dip with only one or two deaths, which were in all probability due to weakness. The dips themselves as a cause of the trouble must therefore be eliminated from the, case. i

The term ‘ ‘ non-peisonous " as ap-; plied to carbolic or cresylic dips is a misstatement of fact, and in most countries these dips must by > law be labelled "poisonous” and be treated 1 in the same way as other poisons. All these dips , contain the coal-tar product, "phenol" and other oils which are not; very soluble in water, and therefore need some emulsifying ingredients which the manufacturer adds. The manufacturer gives advice as to the 1 best way to mix and use the dip, and such directions should be strictly observed. Hard or brackish water destroys or renders inactive the soap present in fluid dips, with the result that the emulsion is broken up and the. acids and oils are liberated. The effect of this is that when these acids and oils are inhaled pneumonia supervenes, usually with fatal results, and this is,; what occurred in the cases under re-' view. ’ Several Causes. I am of opinion that there was a combination of causes to bring this about:— (1) The summer being dry tho water was possibly not as soft as usual, and in the absence of rain most of the water in the races came from springs. I had one lot of race-water analysed,

and although it proved to be soft there was evidence afterwards that rain had fallen between the time of the fatal dipping and the time the sample was taken. Mortality was not general, but occurred in patches where tho sources of the water-supply were similar. (2) ApaTt from the water, the dips were mixed in various ways and were not always formed into a proper emulsion before putting into the bath. The phenols and oils would float to the top, and the sheep on rising to the surface would be more liable to inhale them into the lungs, which in faet did happen. (3) Sheep driven straight in off the paddocks and dipped on a full stomach would be more liable to inhale the fluid than sheep with empty stomachs. This occurred in some cases(4) Numerous rams which died were in high condition ready for the season. Such animals require special care in the dip. , Precautions. In conclusion, all farmers may be advisod to take the following precautions when dipping:— (1) Do not dip sheep while they are in a heated condition, nor heat them up by driving after dipping. (2) If the water is hard, soften it by adding 21b. washing soda to every 100 gallons of water. (3) Follow directions given with the dip and mix it overnight, stirring again'before using. (4) Avoid dipping the sheep on a lull stomach. (5) Take time, and do not rush the 9heep through the bath. (6) Use the crutch yourself. (7) Remember that dirty-woolled sheep means soiling of the dip, thereby weakening it and rendering it more or less inert, with the result that the sheep are not- preperly treated—which may result in their being “ ticketed” at the sale-yard 9. (8) Run off the dip-fluid after dipping is finished. (9) Put fresh water in the dip and run it off again before the first dipping of the season.