EXTERNAL PARASITES OF SHEEP.

New Zealand Journal of Agriculture, Volume XV, Issue 2, 20 August 1917, Page 73

EXTERNAL PARASITES OF SHEEP.

ERADICATION OF TICKS IN NEW ZEALAND. Paper read by Mr. ALFRED MATTHEWS, Waiorongomai, Featherston, at the Annual Conference of the New Zealand Council of Agriculture, July, 1917. The question of the eradication of ticks on sheep is a very difficult one ' to deal with, and there is certain to be a great difference -of opinion in connection with • my views on this matter, which are the result of over .fifty years' experience. I think it will be necessary to take you. back to the early history of our flocks in New Zealand, when they were largely infected with scab and that disease ’ caused so much loss and worry to the sheep-farmers, of that period. Want of information relative to the habits of the insect, and primitive appliances, caused the early settlers in many cases to struggle on for years before effecting a cure. '

I first had to deal with a scabby flock of over eight thousand merino sheep when I was under twenty years of age. I had not seen the disease before. I knew nothing about dipping ; in fact, I had never seen a dip, nor did I know where to go to see one. I visited some settlers I knew to try and glean some information, but each one gave different advice, and the Sheep Inspector did not assist me much. One old friend advised me to start shearing at once, and to stand by and rub my hand over each sheep as it was shorn, and when I felt a spot to at once scarify it with the point of my knife, and then apply some tobacco-water to it, which I must keep handy in a bottle —rather a tedious process with the number of sheep I had to deal with. Another friend consoled me by stating that as the run was very rough, and bounded by a mountain-range swarming with wild sheep and no fences, I had a work of years before me.

Some time after I was in Wellington and saw in a bookseller’s window a small pamphlet. called Scab and Its Cure/’ by Alexander Bruce, Chief Stock Inspector of New South Wales. As the disease was originally brought from that country to New Zealand, and as for many years scab had existed there, I thought the pamphlet worth obtaining. I purchased it for . is. pd., and I have often stated that the information ■it supplied saved my father at least £2,000. By following instructions I was enabled to effect an absolute cure, and when the Inspector granted a clean certificate he stated that one other settler only had been equally successful.

The dipping-mixture then used .was made up of tobacco and sulphur, but later on lime and sulphur, a much cheaper dip, came into use and proved very effective. The Sheep Act was very stringent ; progressive fines were imposed, and in some cases the Inspector took charge of a settler’s flock and cleaned it at the owner’s expense. Some of the Inspectors were experienced and capable men, and better able to deal with a scabby flock than many of the sheepfarmers. Although when scab first broke out fencing was expensive, wire fencing being almost unknown, the country extremely rough, with numerous wild sheep in places, and sheep generally very difficult to muster, the disease was eventually stamped out, and there has been no return of it. Sheep-farmers are now in quite a different position from those early settlers who had to contend with scab, and should find no difficulty in eradicating ticks, as they now have proper appliances for dipping. The country has been largely cleared of bush and scrub, is divided and subdivided with good fences, and, except on some of our mountainous country, there is no difficulty in mustering the sheep.

The tick {Melophagus ovinus), or ked as it is termed in England, is not a troublesome parasite to destroy, as it is unable to live for more than from four to six days off the animal under favourable conditions. It does not lay eggs, but its young are brought forth as pupae, which are attached to the wool fibres and develop in about twenty-one days. Although it is an easy matter to destroy ticks with, one dipping, it may be necessary, in order to exterminate the pupae, if the right time is not selected for the work, to give a second dipping. At present the Stock Act allows sheep-farmers in the. North Island the months of January, February, and March, and in the South Island February, March, and April, in which to dip their sheep and if the season is dry and there ■ is a shortage of water the Inspector has power to extend the period to any one applying for an extension of - time. The result is that one sheep-farmer will perhaps dip early in January, and his neighbour may not do so until late in April or May, and with only wire fences, and not always secure ones, between the two flocks, you cannot expect dipping on such lines to be successful. In January last year my son purchased some lambs from a neighbour, and saw them dipped before he brought them away. The man had just dipped the rest of the flock in the same careful manner in which the lambs were treated, yet ,at shearing- not a single tick was found on the lambs purchased, but : the flock from which they were obtained was badly infested; and this could only be attributed to the careless system of dipping adopted by his neighbour and carrying out the work late in the year. . :

I consider that the time allowed for dipping should not exceed six weeks, and the period should extend from Ist January to about the middle of February —-a time when there is seldom the same scarcity of water that there is later on. Many will say that at that busy time of the. year the work of dipping. could not be attended to. . Dipping is as essential at that time of year as nearly any other class of work, .and you can do a lot of it in a very short time if you wish, and I am quite certain if .you extend the present period there will be a number of our sheep-farmers who will not find time to dip until near the end of the term allowed. ' I have for many years dipped shortly after shearing, and I am now quite convinced that it is the right time to carry out the work, as, although I never dip more than once during the year, my flock . for some time has been absolutely free from ' ticks or lice. My sons, who own parts of my old property, and dip about the same time, have also clean flocks.

If dipping is carried out shortly after shearing, especially if lambs are shorn at the same time as the rest of . the flock, there will. only be the live ticks (and few of them) to deal with, as the pupae cannot well adhere to the short wool of machine-shorn sheep. I do not think ticks increase to any extent during the very hot part of the year, as they appear to be in a semi-dormant .condition, similar to the acari of scab, which appeared to make no progress during that period of the season,' but spread over the sheep very rapidly when the autumn rains set in. I ■ have never found late dipping satisfactory, 'as you have not only, a greater number of ticks to destroy, which seem particularly. active at that time, but also a very large proportion of pupae, some of which will escape and if heavy rain follows dipping the sheep will then soon be infested as before. Late dipping is much more costly, is not as effective, and is of little use as regards the fly trouble, which would be the only benefit from dipping if ticks and lice were exterminated.

If sheep are clean dipping is unnecessary, except for the fly, or perhaps to prepare sheep for show purposes or for sale ; but it does not in any way assist the growth of wool, for if a flock is properly cared for Nature provides all that is necessary to promote woolgrowth. .

The present Stock Act will not assist in the eradication of ticks. It deals to some extent with lice, and if infested sheep are found in any public place the owner can be summoned and fined; and a sheep-farmer can be compelled to dip his flock if an Inspector finds it to be infested with ticks, which does not often happen. Section 48 of the Stock Act states that if an Inspector is satisfied that any sheep in a flock are infested with lice or ticks he may give notice to dip, but if sheep are to be slaughtered or are fit for that purpose

he may postpone the notice for fourteen days. This reads as though the sheep can be driven to be slaughtered for any distance in an infested condition. If the owner refuses, neglects, or fails to comply with the notice he is liable on conviction to a fine not exceeding £SO ; and if after such conviction his sheep are not immediately dipped to the satisfaction of the Inspector a further fine of £SO can be imposed ; and so on for each conviction. I believe this section is rarely, if ever, enforced. Under section 51 an Inspector cannot compel an owner to dip immediately before or just after lambing.

There is no supervision by Inspectors in connection with dipping, and, with the large number of flocks we now have in New Zealand, it would be too costly a matter to bring about. When scab existed the Inspector was expected under the Act to inspect each flock at least once every year. To do so now in our large districts would be a severe task for any Inspector, especially with the large amount of office-work he has to contend with. Undoubtedly, dipping in many cases is carried out in a very careless manner. I have heard of instances when the supply of dip ran out in the middle of the work; but that did not trouble the owners of the sheep, as they added water until the dipping was completed. Careless mustering also interferes with successful dipping, and on hilly country, especially if the work is left until late in the season, there will often be a number of weak lambs unable to travel to the yards. The constant movement of sheep to and from saleyards in the autumn causes trouble to the careful sheep-farmer, as weakly sheep sometimes knock up, and drovers occasionally lift them over the fence into the nearest paddock, hoping to recover them later on ; and in many cases these are undipped sheep.

Every sheep-farmer should have a dip on his property if he wishes to dip effectively. The owner of a small flock does not require a long, expensive dip, but a short one or a small round dip will meet his requirements, provided he keeps each sheep a sufficient time in the bath ; and for small lots of purchased sheep it saves expense. I cured eight thousand scabby sheep in a dip only 9 ft. long on the top and 4 ft. 6 in. wide, and my present dip is only 25 ft. long.

In my opinion, ticks and lice should be stamped out absolutely throughout the Dominion. We cured our flocks of scab many years ago under very great difficulties, and there has been no return of the disease ; and if we dealt as effectively with ticks and lice we should have no further trouble with those pests. Old settlers often expressed the opinion that poverty-stricken sheep produced scab. If that were the case we should have it with us at the present time, as there are always some miserable sheep in all flocks. The same argument is often used now in connection with tick and lice ; you

are told that poverty produces the pests, as poor sheep are always more infested than fat ones; and this is certainly the case. The poor sheep .do not produce these parasites, but prove , a congenial breeding-ground. A sheep-farmer' a short time ago told me quite seriously that he was sure . that - ticks were transformed into flying insects, and quitted the sheep at a certain time during the year.. Perhaps wings carry some of them off in a certain way, as when the fleece becomes long in early summer ticks are found on the outer extremities of the wool, and then starlings have a good time. Spontaneous generation of insect-life is out of the question, and if our- flocks were once cleared of ticks no return need be feared, unless they come from imported sheep, which can be easily prevented.

Most of the poisonous dips give satisfactory results if used carefully, but some of the directions for use are rather ridiculous, as they allow a different, strength for lambs, long-woolled sheep, and merinos. Surely, if a weaker mixture will kill ticks on iambs it will also kill them on grown sheep. Non-poisonous dips are not satisfactory I found when I used them many years ago that my flock always suffered to some extent from ticks and lice. . . ■

I am perfectly aware that all I have stated in this paper will be quite useless as far as the eradication of ticks is concerned unless our Stock Act is amended and similar sections to those formerly dealing with scab brought into operation in connection with ticks —which is hardly likely to take place. If dipping could be confined to a short period soon after shearing it would mitigate the evil considerably, but if all our sheepowners were compelled to dip carefully during that time I am quite sure that ticks would soon be eradicated. We, however, know well that a number of our sheepowners will not exercise sufficient care, either in mustering or dipping, and unless compulsion is exercised we cannot hope to stamp out this curse to our flocks. The same apathy exists in England relative to scab, where it has existed for centuries. In the last report I saw it was stated that there had been one hundred outbreaks there in excess of those of the previous year ; and this occurs in a country where there should be no difficulty in effecting a complete cure of the disease in a very short time.

In conclusion, I may state that I have had to deal with my flock under nearly all the conditions that sheep are likely to go through. I have had them swarming with lice, with considerable loss of wool; I have had their wool almost a chocolate colour through ticks, and consequently impaired in value. But I then. dipped at any time during the season when it suited me, and chiefly with non-poisonous dips. Eventually I used a good poisonous dip shortly after shearing. Lice at once disappeared, and I have not seen one for many years

past; and ticks soon followed. Dipping is costing us a lot of money every year, with not sufficient result, as we only to- a certain extent check the increase of the pests, but under the present system , will never eradicate them. In this paper I am expected to deal with ticksonly, but I have brought in lice to some extent as well, especially as I believe that the treatment suggested for the one will apply to the other. I know many of you will not agree with my views on this subject, but they are the convictions of one who has taken a practical part in the management of his flock for the greater part of his life and has been fairly observant and successful.

Note.—We have pleasure in printing Mr. Matthews’s interesting and suggestive paper. It may be mentioned that the Department consistently advocates—both through its field officers and in print—early and repeated dipping. See, for instance, the article on “Sheep-dipping,” by Mr. J. L. Bruce, in the Journal for November, 1915 ; also New Series Bulletin, No. 64, September, 1916. Steady pressure is also brought to bear to enforce the law as it stands. —Editor.