PREVENTION OF PARASITIC DISEASES IN SHEEP

New Zealand Mail, 15 February 1900, Page 8

PREVENTION OF PARASITIC DISEASES IN SHEEP

‘By Professor J. Wortley Axe, in (he "Live Stock Journal.”)

Theio can be little doubt that in this doPc.rtmen, or agriculture many have found salvation from insolvency, and not a f-w achieved an enviable share of prosperity nhile to seme sheep husbandry has proved a disastrous enterprise. All, however ha\e from time to time experienced in greater or less degree the adverse influence ot disease and especially those msnvand tin ‘R lment ® Y hicb result from parasi- - T? 00 * 1011, It is, perhaps, not overstatlng the case to say that two-thirds of the JZ aS % an , d morta,i ty occurring in our ;^T kS , are P arasi tic origin, and notwithstanding the vast strides that have been mace in sanitary science, and our much larger acquaintance with the lifeeases of tw b f blts of oviae Parasites, disases ot this class are much, more prevalent to-day than they were 30 years aFo That a more enlightened system of sheep mana 4fw* now . Practised in special cases over ttiat of so long past may be admitted-mlVi-n equall r true , tha t the average farinnl Vf P ersis .t? 111 disregarding the teachmgs or preventive medicine while placinc S ls1 * confidence in the curative in? fluence of worthless, and in some instances dangerous nostrums. Of all oiir farm animals sheep are far away the most frequently and severely affected with parasitic Vo the^tT 1 “ d inter °al. and j“'Y aM the latter, no animal offers menf thaTfhey'do? 688 medical treat ‘

The reason for this will be obvious when rte 6d W l Br f at is the total capacity ot the several stomachs of tlio ruminant, and how medicines when inr-or-dlhfterl wi t h i Vi 68 - 6 bulk y contents become diluted until their active vermifuge r>™ perries are attenuated and reduced S plmort 8 ° s?ifl 1 fl 1 r t t>,p P r oin V Th ? obstacle to s«“ ess is sail lurther enhanced bv the cn-pit o/ life and; resistance ovine paiasites display towards so-called "worn ib T ay S“t difficulty even'fh^urrYst carried to unreasonable length! is’seldom attended with satisfactory results and then only when repeated againanda-afn In order to obtain the best effects re medicinal treatment the agent emn/oved must be giver, to each animal senaratelv wnn the food it is impossible to ensure uniformity in the amount consumed bv each ammal and to guard against dangers resulting from an overdose. Haviim regard, therefore, to the troublesome. ?<fstrt »nd uncertain results of treatment it becomes of the first importance that farmers on d tb; e V herdS shouid kee P a watchful eve on the known means by which parasitic diseases may be prevented, and their more serious effects averted. In this connection the lamb flock becomes of special interest tor it is during the early months of lamb l.fc. yhaa growth 18 most active and good health most needful to early maturity, that the body is raided and invaded bv the various parasitic pests. It must not. however, be supposed that while the lamb flocks are ravaged the older sheep are entirely free. On the contrary parasites of one kind or another, or of several kmds are always to he found in adult sheep, but seldom in numbers hurtful, to the individual. Why this should he so we need not discuss here, further than to say that such few as exists in harmless seclusion in the-;body of the adult are capable of furnishing to the soil eggs and larvae in numbers sufficient, in infest and to kill large numbers of lambs.

For the most part the ultimate effects produced bv parasites will depend upon the number whicn the bearer carries, but this is by no means necessarily the case; parasitism is a condition in which there are two opposing forces, the parasites on the one hand, and the vital resistance of the host on the other. lif the former are numerbus and the latter feeble, the con-flict-will result in favour of the invader; but if the lamb be well nourished and of vigorous habit, he may by good management be able to live down tne enemy, or, in other words, hold him in cheek by virtue of his vital resistance, and ultimately eject him from his stronghold. From these considerations it follows that in a country like this, where sheep land is heavily stocked, or, better, overstocked, year after year, and the chances of parasitic infection are so great, measures ot prevention must commence w ith the breeding ewe, for upon her will depend in a large measure the power of the young to withstand the ravages of disease. Breeding ewes therefore, should be kept in good condition, not only that the lambs may fall strong and vigorous, but also that they may continue afterwards to receive a plentiful supply of natural food and maintain a high standard of health and growth. A large experience of parasitic diseases m sheep enables us to say that of the groat mortality annually resulting from this cause, thousands of lambs succumb for want of that robust condition and natural resistance which they owe to the well-doing of the darn. The heavier losses are invariably found where, from economical or other reasons, ewe flocks have been pinched for foood, and lamb down in a weak, impoverished state. Beyond this, there are other and equally weighty considerations which should engage the attention of the flockmaster in looking forward to lambing time. Among these will be the question of the land over which the flock are to run, and here it is important to observe that pastures stocked the previous year with infested sheep should be strictly guarded against, and especially where the range is of limited extent, for when the soil of small enclosures is contaminated with the eggs and larvae of parasities, the danger of serious and fatal infection is very considerably increased. Pastures heavily stocked from year to year with what may appear to he healthy sheep present a growing danger to lambs, and especially if given to dampness, or in seasons of heavy rainfall, and they become all the more mischievous where the herbage nas been eaten down before the young flock are turned in. A wide range, a frequent change of pasture, and a good bite are important provisions against parasitic infection. , The transmission of internal parasites irom one sheep to another is effected either by eggs or larvae discharged from infe.er-id The fate of these elementary forms will depend upon the condition of the soil over which they are scattered, and tl oir general environment. In all of them moisture favours their endurance and development, while dryness tends to lower their vitality and ultimately destroys them. This leads us to point out the danger arising- out oi bogs and swamps, damp places, dirtv ditches and ponds, all of which may at one .line or another become veritable plague spots. The larvae or young of some of the most destructive parasites take up their abode in riie mud and organic filth in which these places abound. The blood-sucking Strongylus contortus. a parasite which causes immense losses in our lamb flocks, os well as other nematode worms, revel in the dirt of ponds, slowrunning streams, and swampy places. To safeguard the lamb flock from the evil eonsequences of these places requires that the termer should be periodically cleansed, whiie ail bogs and swamps should be periodically cleansed, while ail bogs and swamps snould be fenced in or freelv dressed each spring and autumn with salt, in this connection it is necessary to obscure that mild removed from ponds should not be used for dressing pasture land, as is commonly clone, but should be thoroughly plough 171411 hme and applied t 0 laad under No account of the prevention of parasitic dieases m sheep would be complete without reference to the danger attaching to dogs in whose intestines no less than three’ species of tapeworms commonly take up their abode, whose juvenile or larval form? bin rM 6 condltlon of what are known as bladderworms, are parasitic to sheen and no farmer can be said to take an mMHgent interest in his flocks who does not understand the irrfein facts relating to the ti!re 8 aSa Tn ”tb i nd deVel °P mcnt of these creatuiee. in this connection, then it mo«t vll?p°ed e ii-e U hi! h i at tap , eW ° rffiS are not doeioped birds, and some other creartlnrd ri n r6Ct y from the e kS, but are deffj n ~ ,0 assume an intermediate form m« d ) C t OT 'n through which they must j;t c-SPjJS-M&TS ™2\w ay be briefly stated as Follows : _ or h the letter ta ,f GW ,T' m ' vhile in the bowels or tbe lattei, break up into little white flat segments, which from time to time are Tbp?? lged i Wlt ? the excrement of the dog These are loaded with eggs, which soon reo^o?! 1 i o f] ta?uillate th e herbage or ditches ! their wa y mto ponds and i..cues. Some are swallowed with the of o othere at flil o iU h | Sheep ’ while thousands the bodv’ofTbi g -° R ama » entrance to on, !,!E e ° v T lne best, perish and de-bow-els'of f J * »WV -aeoduroD • i the sheep, each tanevrorm opt discharges a minute embryo, and this bv wav b fn eans ns yet unexplained. « ! its tin? bo civ Therein 1 ! 161 ; ° f * he organs of commonly termed gid or sturdy is found to result from fin d It ImfFw a y!fn t <? I he ?u ngs ? t h e Hver rt lie and ’destroy e Structure 1 ’of Vlfe mgans. In order that these hydatids or so called bladderworms may become taneManTffiYr mU r t pas , s baclc into the dog. asrnm fr°i, r f Urn to their cailine host, the“heen f tbe tapeworm eggs fail to reach rne sneep. It, however, the infested oreaiiß dog th fhin the bfd 1 ? b ° 0011811 med by R tlie vflo’n iifFn Vil bladderw’orm proceeds to-de-velop mto the tapeworm, and thus the life-

cycle of the parasite is eomnletsvr tY* .. considerations it will be r.b-" rlogs harrying tapeworms ore menace to the flock, and as deaß with Here it impSjl & member that, -while tapeworm? i to fc. most pant are sulficiently W e &K the their presence known by the w-h,L t lD ak« : appearing in the excrement some so small as to be easil’v „ an. and if f beep are to be protreted ffderworm diseases all dogs on receive at least three doses 0 f !? m ah ould cine each autumn, or whom 0 ”® are noticed to be infested. \Vhef 6 f chseases ere found to exist in sh«Y yda tjd invaded organs should be burned * ?’ % means of destroying the larval a Sa te thus preventing its retiu-n to L PaVasitc . bearer. With these and other ary measures tlie flockmaster Shm, a,T'on-c-rcise mery care in the purchasa?rH e »‘ stock, and especially so in regard fresh Poor, mAhritty, and " especially to be avoided, as are a k? ls ar , s as are coughing or scouring 180 Eac lb The introduction of such animal- : found land hus frequently been th- l 08 mg point of serious and chntinnon? ii tart ‘ Sait should always be o CM S to & and indeed to sheep of every description ’ - *