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This article was published in 1950
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Lice Infestation in Sheep


K.V. BYRNE, B.V.Sc., Inspector of Stock, Young

From time to time laments about prevalence of sheep lice appear in the press and elsewhere, and resolutions are passed by sheep owners' associations asking that something be done about it. For years, also, the problem has been receiving attention from officers of the Department of Agriculture and Stock Inspectors, but despite all this the position continues to be unsatisfactory. It will remain so unless there is some change in the method of control and the purpose of this note is to suggest changes.

First, the cause of the prevalence of lice must be appreciated and this is not hard to discover. It is basically lack of care on the part of sheepowners. This lack of care comes under two headings:-

1. Lack of care in ridding flocks of lice infestation. 2. Lack of care in preventing flocks from becoming re-infested after dipping.

It is a fact that the majority of owners are not guilty of the first type of carelessness. Most owners know there are several highly

efficient dips on the market for the control of lice and all that an owner has to do to free his flock from infestation is to make intelligent use of one or other of them. The majority do so but a minority do not, and the latter are the major villains of the piece because it is through them that lice are enabled to persist from year to year.

Because these latter are a minority the position would not be so bad if the infestation were to remain confined to their flocks, but, unfortunately, it does not and it is the spread which makes the position really serious.

Some of this spread is to the flocks of neighbours or as a result of contact by travelling lousy sheep, and of course it cannot be said that the owners whose sheep have become infested in this manner have been in any way careless. It is in the major cause of spread that the carelessness indicated under Section 2 is manifested; and that is in the buying and selling of sheep. In this connection the majority of sheepowners offend.

Although, as has been said, most owners will carry out effective dipping, they will take no precautions to see that they do not undo the good work by buying verminous sheep, and it seems to be a waste of time urging them to do so. This is particularly noticeable in saleyards, where, although most intending buyers will examine the sheep for age and type of fleece, it is a rarity to see anyone inspect them for vermin.

No doubt some ask in querulous tones why Stock Inspectors do not stop this trafficking in lousy sheep. The answer is that at present there are thirty Stock Inspectors to cover all the sheep districts of the State from the Tablelands to the South Australian border and they are able to devote only part of their time to sheep vermin work. It is, therefore, not possible for them to attend more than a small proportion of the public auctions that take place, and obviously have no chance of supervising paddock sales. Sheepowners, therefore, need to make some effort to protect themselves. If they did and it were to become universal for them to refrain from buying lousy sheep, the problem would be solved, because if it became impossible to sell infested sheep the minority who fail to clean up their flocks each year after shearing soon would join the ranks of those who do. However, this is an idle dream as sheepowners have shown that they will not take such precautions, and pleading with them to do so is not one of the suggested methods of improving the position.

If any significant improvement is to take place, therefore, it will be necessary to take more effective action along one or other of the following lines:

1. Forcing all owners of infested flocks to dip effectively.

2. Preventing the spread that takes place from those who do not.

It is to be noted that the Departmental efforts to cope with the position have been along such lines. Wherever infested sheep are detected they are quarantined until effectively dipped; and by inspections at saleyards and elsewhere as much as possible is done to prevent spread. However, despite such efforts, lice remain plentiful and the reason is that the staff is not big enough to cope with the job.

If action under heading 1 were complete it would mean eradication of the sheep louse.

The popularly suggested remedy in this connection is compulsory dipping for all, but compulsory dipping has been tried elsewhere and failed because the staff has not been available to see that only effective dipping is carried out. Another major objection is that it is not justifiable to compel an owner to dip sheep unless they are verminous.

The only sound method of eradication is property by property inspection of the whole Australian mainland and compulsory effective dipping of flocks found to be infested. This, obviously, would require a great deal of manpower and expense but this expense would not be as great as the sum total that will be lost by sheepowners in the years to come; through dipping costs and the harmful effects of lice.

However, as we live in a country in which rural problems do not loom very large in the minds of any electorate, no doubt the money will not be found.

We will have to turn, therefore, to a consideration of action under Section 2. As has been said. there is no doubt that the major cause of the spread of lice is the buying and selling of infested sheep; particularly in saleyards. In this latter connection dealers play a major part. It is a common occurrence for these operators to buy a dozen or more lots at a sale, mix them, take them to another sale, redivide them into as many lots and sell. When bought at the first sale, possibly only one lot may have been lousy but as a result of the boxing, all lots sold at the next sale are infested. The result of this action is that where originally there was only one infested property there are now twelve, and as this is occurring week after week all over the State the effect on the prevalence of sheep lice can be imagined.

However, all the blame cannot be placed on dealers, as they are not involved in the sales of verminous sheep that take place and the basic trouble after all is that the majority of sheepowners will not examine sheep before they buy or sell them. Sheepowners quite commonly consider that they have cause for complaint because this job is not done for them by Stock Inspectors. For the benefit of such people it is repeated that it is an absolute impossibilty for the thirty Stock Inspectors at present on duty in the 50 sheep P.P. Board Districts of the State to be present at all sales. Even if they had nothing else to do but attend sales they could not cover the work completely, and in fact they have many other duties apart from saleyard work. Some of these other duties also take precedence over the latter and if, for example, an Inspector is called on to investigate a serious mortality in stock on the day of a sale he has no option but to miss the sale. In many districts, also, where there are a number of saleyard centres quite frequently there is more than one sale or the same day.

The obvious answer to this position is an increase in the number of Inspectors, and it is contended that if the staff were big enough to ensure that no public auction of sheep took place without examination of the yarding, lice would cease to be a problem. It would produce this result not only because of reduction in spread but also by its salutary effect on those who do not make a practice of effective dipping; as an infested flock would in effect be debarred from the auction yard, the popular method of disposal.

This increase in staff would not necessarily mean an increase in the number of Stock Inspectors as appointed at present since detection of sheep lice is not a skilled procedure but something that can be taught to anyone in a few minutes. All that is required for a saleyard inspector of sheep, therefore, is a man of reasonable activity and reliability, and no difficulty would be experienced in obtaining such men if the necessary finance were available. In many centres where the saleyards are run by the local Shire or Municipal Council there are already in existence officials appointed by the council for the purpose of carrying out such duties as collection of saleyard fees; but they do not inspect the stock. However. they usually are present at the yards each sale day and the possibility exists that they would be prepared to examine sheep for external parasites if given extra payment for this work.

An additional advantage in the appointment of such saleyard inspectors would be that existing Inspectors of Stock, most of whom now are qualified veterinarians, would have more time to devote to work for which a veterinary training is essential. It is considered, of course, that it would be most desirable that the Inspector of Stock supervise, and accept the responsibility for, the work of any lay appointees. There not unnaturally is a great temptation to slum this work, so that fairly close supervision is essential. Perhaps one of the reasons why no real progress has been made to date is that those at present doing the work are not under adequate supervision; though it must be realised, of course, that by far the greatest difficulty at present lies in the fact that this work must be sandwiched in with so many other urgent and important duties.

But any action along the above lines would cost money and if no additional finance is forthcoming, and the methods that have prevailed up to date continue, there seems little doubt that sheepowners can look forward to a perpetual wrestling with the Sheep Louse.


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