SHEEP-DIPPING METHODS

Timaru Herald, Volume CXLIII, Issue 20669, 6 March 1937, Page 15 (Supplement)

SHEEP-DIPPING METHODS

WILL SPRAYING PROVE MORE EFFECTIVE? TRIALS IN BRITAIN Is sheep dipping out of date? Does total immersion in a bath of dip diluted with water really perform the function for which it was designed? To those who have doubts as to the efficacy of the present system, the newer method of spraying may have an appeal. It has certainly attracted attention in Britain where the spraying system has been developed. Dr Allan Fraser, who attended a demonstration of sheep spraying arranged by the North of Scotland College of Agriculture, makes some pertinent comment on this question to The Hawke’s Bay Herald-Tribune. “What are the disadvantages of dipping that a new method should be sought?” he asks. “Obviously, if the customary method were a hundred per cent, satisfactory, a search for improvement would’be a waste of time. Ordinary dipping is, however, far from being entirely satisfactory, even when properly performed, and I have recognised that fact for some time. As sometimes) done, it is a perfunctory compliance with the law’s requirements, and, from the point of view of benefit to the sheep, a pure waste of effort. Present Weaknesses “The following are, in my view, weaknesses in dipping sheep with ordinary dips and in the ordinary way. In the first place the dip does not always penetrate to the skin—the place where its action is wanted. I have often examined sheep in the dipping pens and found the skin perfectly dry. In the second place the strength of the dip is not constant. One fills the bath and pours in sufficient to make a correct dilution. So far, so good. But by the time, the first few sheep have been dealt with, is the strength of the dip the same? To judge by the colour of the sheep it is not. The first sheep always come out darker than those that follow. I understand that chemical analysis shows much the same sort of thing. “Thirdly, by the time the dipper is ready for refilling it is more than a little dirty. The dung floats as a scum on the surface, and it is difficult to skim off. If the sheep happens to be scouring, the water may be quite foul. Since soiled wool is an attraction to blow-fly, a dirty dipper may become an actual cause of strike.

“In the method of spraying I saw demonstrated these three disadvantages were entirely avoided. The dip penetrated to the skin; the dip was always of the same strength; there was no fouling of the dip by dung. The method itself was quite simple. A small engine worked a pump which forced the dip through flne nozzles. The spray produced was like driving mist. The nozzles opened into a metal cage containing the sheep. “Judging from what I saw the method was effective. After standing quietly in the cage for half a minute the sheep when released, was soaked all over and to th® skin. Ingenious Accessories “There were several gadgets which I thought Ingenious. For instance, a bar operated by a lever pressed the sheep into position from behind and held it there. A removable tray collected the droppings. Everything was workmanlike and convenient.

“There thus appear to be several very real advantages in spraying sheep rather than in dipping them. Of course, the apparatus costs money, but so does the installation of a dip. I very much doubt whether the spraying machines would cost as much. There is no more labour required and there is an economy in dip. It is also claimed that spraying is a better prevention of blow-fly than dipping, but I think more evidence is needed to prove this. “Unfortunately, at the present time, spraying does not satisfy legal requirements, and I cannot see any sheep farm running to a dip and a spraying machine. Certainly, spraying would need to have very substantial advantages over dipping as a protection against blow-fly before such a double expenditure was justified. On the other hand, I do not see why spraying should not be equal or superior to dipping. If half a minute in a spraying machine of approved design were accepted as a legal substitute for complete immersion, then I feel there would be a future for spraying. Otherwise, since the dipping is forced on us by law, the spraying machine must wait.”