The prevention and treatment of blowfly strike in sheep : report no. 2 / by the Joint Blowfly Committee (Appointed by the Council for Scientific and Industrial Research and the New South Wales Department of Agriculture).
- Date:
- 1940
Licence: In copyright
Credit: The prevention and treatment of blowfly strike in sheep : report no. 2 / by the Joint Blowfly Committee (Appointed by the Council for Scientific and Industrial Research and the New South Wales Department of Agriculture). Source: Wellcome Collection.
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![4] In order to gain some idea of the numbers of flies which might be bred from a struck sheep, three crutch strikes were selected and all maggots carefully collected and bred out. The results are given below. Strike 1 was very small, strike 2 moderately large, and strike 3 very severe, involving the whole breech and rump. Number of Flies Bred Out. Species of Fly. a Strike 1. : Strike 2. Strike 3. L. cuprina .. a “i 87 1,692 | 4,343 L. sericata .. +a re 0 0 | 44 C. stygia .. “ ae 0 | 31 168 C, augur .. ae ee a) : 13 3 Chr. rufifacies .. Bd 0 | 0 | on P. rostrata... ate we 0 | 0 | 301 Total HA ey 87 | 1,736 4,890 Thus, over 90 per cent. of the flies from each strike were L. cuprina -—a very different result from that obtained from a carcass, for which less than 1 in 1,000 emerging were L. cuprina. Even a tiny strike bred more L. cuprina than any sheep’s carcass studied in Canberra. This finding may apply only to the southern part of the continent. Further north, and in the dry inland areas, there is some evidence that carcasses may breed more L. cuprina than they do in the south. The usual practice of scraping maggots out of a strike and allowtng the crutchings to be trampled in the dust, gives L. cuprina every chance to complete its life history. It is evident then that crutchings from struck sheep may be a greater potential source of danger than carcasses. Recognition of the importance of this source of primary flies should serve to stress the fact that, in adopting measures aimed at the prevention of strike, the pastoralist is also attacking the main breeding ground of the fly itse ee However, while it is easy to recommend the complete destruction of all maggots in the crutchings, it is very difficult to do this in the field. Unless sheep are brought into the shed and crutched on the board, it is extremely difficult to collect all maggots with the crutchings. If crutching is done in the yards, most of the maggots will escape into the soil. This may possibly be overcome by the use of a large piece of strong canvas for the collection of the crutchings. When the maggots have been collected, they must be destroyed. No one method is applicable in all circumstances. A choice may be made of one of the following suggestions. The maggots may be shaken on to a fire, or into a tin of hot water, or they may be dropped into a tin containing poison. If this method is used, it must be remembered that dilute solutions of disinfectants, and even arsenical solutions, are not rapid contact poisons, and maggots will soon crawl out of such solutions and escape. Strong solutions of coal tar oils, such as are contained in many proprietary dressings, are good maggot killers. Petrol is a very rapid killer, but is expensive. <A solution of carbon tetrachloride is a rapid contact poison, and some dressings contain](https://iiif.wellcomecollection.org/image/b32175851_0043.jp2/full/800%2C/0/default.jpg)
