THE SHEEP-LOUSE.

New Zealand Journal of Agriculture, Volume 3, Issue 5, 15 November 1911, Page 374

THE SHEEP-LOUSE.

ITS EFFECTS, DETECTION, AND SUPPRESSION.

A. T. P. Hubbard.

Since the eradication of scab from the flocks of the Dominion owners may congratulate themselves upon the comparative immunity which their sheep enjoy from pests generally, Apart from the tick and louse, our sheep are practically free from external parasites. The presence of these, however, entails serious loss both in wool and carcase, and should therefore command the earnest attention of all sheepowners. That considerable apathy exists on the part of many farmers, particularly in regard to lice, cannot be denied, and it is with the hope of removing this, and stimulating renewed energy in combating these vermin, that this article is written.

The tick being larger and consequently more conspicuous than the louse, it is. perhaps regarded by many as being the more harmful, whereas the louse is really a much more serious menace to the welfare of the sheep. Reduced vitality, loss of condition, and injury to the fleece, are each directly attributable to the ravages of the louse, dependent as it is for its sustenance partly upon the blood it extracts from its victims and partly on the yolk of the wool. Owing to continual restlessness of the sheep, caused through irritation, its vitality and condition are rapidly reduced, proper growth of wool is retarded, and the fleece is seriously damaged through constant rubbing against fences, logs, &c. With reduced vitality the louse-affected sheep naturally becomes a prey to other ailments. In this connection

I am of the opinion that much of the difficulty experienced in this country in raising young sheep would be overcome if owners exercised greater care in ensuring that their lambs are maintained free of lice. The rigour of the winter months demands that every endeavour should be made to rid the lambs as far as possible of anything calculated to undermine the constitution.

Method of Detection

As many sheepowners freely admit that they “ don’t know a louse when they see it,” nor know how to look for it, a few remarks in this direction

will perhaps be of. some value. In the majority' of cases where sheep are affected with lice there are generally outward and visible signs of the trouble, consisting of poorness of condition, dry, hungry, or scoured appearance of the. wool, and the fleece is also often broken and tufted, portions having been torn out by the sheep rubbing themselves against fences, logs, &c., in the endeavour to allay the irritation set up by the vermin.

In order, however, to definitely satisfy oneself as to the presence of lice, a closer examination is necessary, and for this purpose the sheep must be caught. After being turned towards the best available light the. wool should be parted, so as to expose the skin to view, and the sheep examined carefully, especially the parts surrounding the brisket, neck, and well up about the ears. Vermin is often found in the ears when nowhere else, owing to want of thorough immersion of the sheep when being dipped, the ears thus escaping treatment and remaining a breeding-ground and start-ing-point for fresh infection. Lice will generally be found well down on the skin, and in badly affected cases the skin is scaly and lacks that pink colour characteristic of the clean, healthy sheep.

Sheep-dipping.

That dipping in many instances is carried out in a very perfunctory manner must be admitted. Carelessness, want of knowledge, and limited means are the main factors operating in this direction. For the successful suppression of vermin in sheep it is obvious that dipping must be universally done, and on thoroughly effective lines. Of the many dipping preparations on the market some perhaps are more effectual than' others ; but while the material used is often blamed for unsatisfactory results it is very often the method employed that is at fault. Proper mixing of the dip and thorough immersion of the sheep are the fundamental essentials of successful dipping. Where circumstances permit and. a large number of, sheep have to< be dealt with, the 60-ft.-long dip is perhaps the best, but where a small flock is kept a less expensive dip, and yet just as effectual, may be constructed by adopting the semicircular type of bath. This class of dip is in use on many small farms, and gives entire satisfaction. It is generally built about 10 ft., long by 5 ft. across, its greatest width. This holds about six sheep at one time, and permits them swimming about freely, until the drainingpen gate is opened and they are released. By this method thorough dipping is accomplished ; whereas in the short straight dips, so often found on small farms, ' the sheep cannot be retained sufficiently long to ensure proper 1 immersion, and consequently little good results. As- regards the best time to dip, there is a diversity of opinion, but the best solution of that 1 problem is, I consider, to dip twicethat is, firstly “ off the shears,” or soon after shearing, and. again later on, but during

the statutory dipping-period. The first operation costs comparatively little, owing to the,shortness of the wool, and it rids the lambs of the parasites which desert the older sheep as soon as shorn. The second dipping will destroy the vermin hatched from eggs which perhaps survived the first immersion, and results in the flock being in good clean condition to face the winter months. Where this practice is adopted a poisonous dip is considered preferable for the second dipping on account of its more lasting effect. The idea which largely prevails amongst sheepowners —that vermin are a necessary concomitant to poverty—is entirely erroneous. Neither lice nor ticks can arise spontaneously. Low condition is certainly conducive to the increase of vermin, but if a sheep was absolutely clean and was not exposed to infection from others it would not develop vermin, no matter how poor in condition it became.

Legal Requirements.

The Stock Act of 1908 requires that all long-wool or crossbred sheep must be dipped annually between the Ist January and the 31st March in the North Island, and elsewhere between the Ist February and the 30th April. Also, that if at any time lice or ticks are found in a flock the owner may be called upon to dip. Lice-affected sheep must not be driven along any highway without an Inspector’s permission, nor must such sheep be exposed for sale.