module 9 – parasite control - going into goats | mla · from the meat & livestock australia...

The following module has been adaptedfrom the Meat & Livestock Australiacommissioned report Options for the controlof parasites in the Australian goat industry,2007.

What to do?Parasite management is about riskmanagement and reducing the risk ofinfestation is essential to any goatproduction operation. Factors to consider inmanaging internal parasites include:

• Grazing management

• Visual assessment of animals

• Animal selection

• Faecal egg count testing

• Responsible chemical use

How to do it?This module describes various parasiteproblems that may be encountered in goatproduction and presents options availableto goat producers to minimise theproduction risks associated with internaland external parasites.

Guidelines for controllingnematode parasites of goats inpasture–based systemsWorms, or parasitic nematodes of thegastrointestinal tract, of goats are a majorconstraint to efficient production inpasture–based systems worldwide.

The overuse of chemicals to control wormsin the sheep and cattle sectors has led tosignificant resistance issues and anecdotalevidence suggests a similar situation ingoats.

The sustainable control of worms involves adramatic reduction in chemical use andincreased diligence in monitoring for wormburdens, testing drenches for efficacy andincorporating browse and nutritionsupplementation as a minimum standard forbetter worm control.

Less reliance on chemical use is importantin preserving those drench actives stillgiving good control. Management of wormsis as much about management of drenchresistance as it is about the wormsthemselves. Without a change in attitudetowards drench usage, drenches currentlyeffective are unlikely to be so in a year ortwo.

The integration of non-chemical controlstrategies with infrequent drenching istherefore imperative in achieving thesustainable production of a residue–freeproduct.

Key nematodes

The major nematode parasites of concern ingoats are the barber’s pole worm(Haemonchus contortus) and the smallbrown stomach worm (Teladorsagia[Ostertagia] circumcincta) that parasitise theabomasum. The scour worms(Trichostrongylus spp.) are resident in thesmall intestine and the nodule worm(Oesophagostomum columbianum) is foundmainly in the large intestine.

Of lesser concern are the thread worms(Strongyloides papillosus) and thethin–necked intestinal worms (Nematodirus)that are also found in the small intestine.The large–mouthed bowel worm (Chabertiaovina) and the small bowel worm (Oes.venulosum) inhabit the large intestine. Thesmall lungworm (Muellerius capillaris) iscommon in higher rainfall areas and thelungworm (Dictyocaulus filaria) isoccasionally found in goats pastured incooler climates.

Module 9 – Parasite control

Module 9 – Parasite control 1

2 Module 9 – Parasite control

Distribution of key nematodes

In summer rainfall zones, barber’s poleworm and the nodule worm are the mostimportant genera with scour worms, inparticular Trichostrongylus colubriformis andthe thin–necked intestinal worm of lesserimportance. In the winter rainfall zone, thenon-seasonal rainfall zone and theMediterranean zone, the scour worms are ofgreat importance with large-mouthed bowelworm of lesser importance. Cold–adaptedbarber’s pole is also important in some non-seasonal and winter rainfall regions.

Worms are rarely a problem in pastoralareas due to the combination of low rainfall,the availability of browse and low stockingrates.

Detecting infections

Most of the clinical signs associated withworm infections are not highly specific butare generally related to intestinaldisturbances such as scouring (winter scourworms), constipation (barber’s pole worm)or hunched back with mucoid scours(nodule worm). These changes in digestioncan lead to inappetance, poor growth, arough coat, weight loss, emaciation due toreduced appetite, scouring and sometimesdeath.

Barber’s pole worm however sucks bloodand heavy infections can quickly lead toanaemia, submandibular oedema (bottlejaw) and sudden deaths. Anaemia is bestdetected through an unusually pale lowerinner eyelid. On smaller properties in proneareas, individual animals can be examinedfor anaemia by checking the lower innereyelids each week during warm moistconditions. See Glossary Eyelid ColourScoring. Individual animals can be targetedand heavily infected goats treated.

Liver fluke and Mycoplasma ovis will alsocause anaemia and in endemic zones theirpresence needs to be considered in thediagnosis of anaemia.

Where scour worms are of importance bodycondition scoring also on a weekly basisbecomes important to detect rapid loss ofcondition. See Glossary Body ConditionScoring.

Laboratory testing

By the time the clinical symptoms abovebecome evident, productivity losses wouldhave already occurred. Laboratory wormegg count testing provides a method tomonitor any rise of worm egg counts andallows clear decision making on the need todrench or not to drench. The latter savesmoney on treatment and helps prevent ordelay worm resistance.

Laboratory testing can offer goat owners anumber of tests to monitor the progress ofinfections over time and to determine wormpopulations and if drenching is required.Most properties in the rainfall zones of >380mm per year carry some resistant wormsand the type and severity of the resistancecan only be determined with the assistanceof laboratory testing.

Eyelid colour scoring for signs of anaemia.

Worm egg count and larval culture: It isstandard practice within the ruminantindustries to base decisions to drench onthe results of a worm egg count for thenumbers present and a larval culture toidentify the types of worms present. Theworm egg count can only determine thesize of the adult worm burden and not theimmature burden.

This is of particular concern during spikeinfections with barber’s pole when warmtemperatures and rainfall followed by a fewovercast days will initiate mass hatching ofeggs in dung and increased survival ofinfective larvae on pasture. In this scenario,worm egg counts are often low but deathsdue to the immature burdens can occur insusceptible goats often within 2 weeks. Anew faecal occult blood field test usingcheap indicator strips which detect freeblood in faeces offers precise usefulness inthis situation.

Worm egg counts taken from weaners andpregnant and lactating does 3-6 weeks afterrain, and repeated at 2 to 6–weeklyintervals, depending on location andweather conditions, will monitor the rise in

infection levels until the season becomesdry and continues dry again.

Drench resistance testing: A faecal wormegg count resistance test (FECRT) is thestandard to determine drench usefulness inkilling worms. This is an on–property trialinvolving 15 goats per treatment group andan undrenched control group. Many goatowners consider the FECRT asunmanageable and prefer to use thedrench–screen option. However this will notdefine resistance to a range ofanthelmintics.

Drench-screening involves selecting out andidentifying 20 young wormy goats of aneven line. Dung samples for a worm test aretaken at–drenching and from the same 20goats, 10-14 days after drenching to lookfor a reduction in worm eggs. Test goats arebest restricted to a house paddock for 14days of the trial. A drench efficacy of atleast 80% is useful if combined withbrowsing strategies and careful monitoringof worm burdens. Checking drenches for achange in the resistance pattern isrecommended every 2 years.

Most drenches are now less than 80%effective increasing the need for nonchemical worm control techniques.

Your local state government or privateveterinary laboratory will assist with trialdesign and procedures for the FECRT andthe drench–screen and will also provideinterpretation of worm egg counts specificto your location.


Nematode eggs.


Controlling infections

The nematode cycle of constant infectionand reinfection can be broken by preventingnew infections and by treating existinginfections.

Preventing new infections

Reducing the size of new infections can beaccomplished by reducing the intake ofinfective larvae from the pasture andstrengthening the host’s ability to preventestablishment of these ingested larvae.

Reducing the intake of infective larvae:Goats are browsing animals and should haveat least 30-50% of their food supplied asbrowse for optimal nutrition and good wormcontrol. Grazing lower than 10cm above theground exposes goats to larval parasites thatcongregate there because of the greatermoisture levels at the soil–grass interface.Separation of the feed from larvalcontamination can be achieved through theprovision of browse. Browse does notnecessarily mean trees. Browse plants, suchas lucerne and other leguminous crops inpasture–based systems, will supply extranutrition when pasture quality is poor,provide food free of larval contamination andcontribute a moderate antiparasitic effectdue to their contained condensed tannins.

Browse does not necessarily mean trees;lucerne and other leguminous cropsproperly managed in pasture basedsystems can provide valuable browse.

Cattle grazed with goats will contributestrongly to better worm control andimprovements in pasture quality. Goat andcattle interchanges are based on hostspecificity. Goats share the same nematodeswith sheep but only one with cattle. Adultcattle are resistant to nematode infection andany larvae eaten while grazing will notdevelop to adults. Attention must be paid tostocking rates however cattle can be grazedwith goats or in rotation with them.

Strengthening the overall immunity toworms: Malnourished goats are particularlysusceptible to nematode infection. Extranutrition in the form of protein, energy andminerals may be required during criticaltimes. This typically occurs at weaning inkids and in does for about 2 weeks beforeand up to 8 weeks after kidding.

Browse is provided here as saltbush.

Larvae climbing the walls of a jar having hatched indroppings. This demonstrates how larvae climbpasture; the longer the pasture the better!

Malnourished goats are particularlysusceptible to nematode infection.

There is growing evidence from othergoat–rearing countries around the world thatgoats have a higher requirement for copperthan sheep. Many goat owners supplycopper as part of a general mineral mix.

During a moderate worm infestation, manygoats appear unaffected while others seemto be severely affected. Identifying thosegoats less able to carry worm burdenswithout productivity losses and culling themwill increase the overall immunity of the herdto worms. These susceptible cull goats canbe managed more intensively in anotherpaddock or sold. In the interim they shouldbe restricted from breeding programs. Thisprocess will have to be repeated for eachherd.

Identifying those goats less able to carryworm burdens without productivitylosses and culling them will increase theoverall immunity of the herd to worms.

Many producers are actively undertakingbreeding programs to produce a betterquality animal. Increased immunity to wormsshould also be incorporated into the indexfor those enterprises in the higher rainfallzones. There is evidence based on worm eggcounts that selection for increased resistanceto worms is possible.

Barber’s pole worms have a huge bioticpotential. Each female worm can lay up to10,000 eggs every day. In barber’s poleendemic districts during ideal ‘worm

weather’ pasture contamination can becomeexcessive in a short period of time. Goatsselected for increased resistance to thisworm can contribute to the control of theirown parasite burden and reduce the need fordrenching.

“At the end of the day it comes down to three critical elements; classing onbody condition and taking the tail out ofthe mob, providing browse as much as is possible and maintaining pasturelength and supplying adequate nutritionto allow the goats immune system tofight internal parasites naturally.” DavidBooth, Cootamundra, NSW

Drenching nematode infections in goats

The need to treat existing burdens can bedetermined by worm egg counts and larvalcultures. Strongly resilient goats are howeverwell able to carry worm burdens withoutproductivity losses and this attribute needsto be considered in the interpretation ofworm egg counts.

Every time a goat owner picks up a drenchgun they should consider the 4’R’s;

• worm RESISTANCE to drenches,

• the number of parasites in REFUGIA,

• the use of REGISTERED drenches and

• chemical RESIDUES in product.

When a chemical treatment is administered afew resistant worms are left in the goatbecause drenches are not 100% effective inall goats at all times. Their progeny thenreplace susceptible worms on pasture. Inother words, a drench becomes less effective



every time it is used, albeit very slowlyinitially. This rate of decline in efficacy islargely influenced by the numbers offree–living parasite stages on the pasture iein refugia. In dry weather when few larvae areon pasture, heavy selection for drenchresistance takes place. Following on fromthis, utilise browse paddocks in dry weatherrather than drenching.

A drench becomes less effective everytime it is used.

There are 3 main areas of drench use onproperty. Most drenching occurs during thebreeding cycle and while growing goats tomarket–ready stage over a 1–2 year period.Other drenching takes place as a quarantinedrench of goats coming onto a property andin the 6-week period prior to sale.

1. Drenching goats during the productioncycle

Only those goats identified as carryingdamaging worm burdens should bedrenched. On smaller properties, individualgoats can be examined and removed fortreatment. On larger properties, drenching ona herd basis is the most practical solution.

Certain BZs, Oralject® (morantel citrate) andCaprimec® (abamectin) drench actives areregistered for goats and Neguvon® (trichlorfonfor H. contortus control) has a minor usepermit. See Module 9 – Parasite controlToolkit 9 page 5. Use of unregisteredproducts will require an off-labelrecommendation from your veterinarypractitioner. It is imperative that accuraterecords of administered chemical treatmentsand their Withholding Periods and ExportSlaughter Intervals are kept. Increasingly goatowners are being asked to nominate any

chemical treatments used in raising their goatsif they are to be sold for human consumption.

Many goat owners yard goats at night forprotection against wild dogs. This nightpaddock is often the source of infection forgoats and, like other paddocks, needs to beincorporated into a rotation system withattention given to cleaning when vacated.Feed and water troughs should be raisedabove the floor to prevent contamination withdung pellets. Leaky water troughs should befixed as moist conditions providemicrohabitats for worm larvae.

Leaky water troughs should be fixed asmoist conditions provide microhabitatsfor worm larvae.

Goats released from night paddocks can beheld in gravel yards until the light intensityfrom the sun is strong enough to force wormlarvae to retreat down the grass blade to thesoil-grass interface. Larvae also move closerto the ground as dews evaporate.

2. Quarantine drenching incoming goats

The quarantine drench is important toexclude resistant worms carried by goatsintroduced from other properties. Since thetype of resistance in imported goats is mostlikely not known, drenching with more thanone active is standard practice. Registereddrenches should be used but not mixedtogether prior to dosing.

If drench resistance is not well controlledby registered drenches, your veterinarypractitioner may be able to give arecommendation for an unregistereddrench. Take care with WHP and ESI.Keep accurate records.

Goats can be held in a quarantine paddockuntil a worm test 10 days later is negativeand then moved onto a wormy paddockcontaining browse. Once that paddock isvacated, it should be grazed by adult cattleor cropped to ensure imported resistantlarvae do not establish on your property.

3. Drenching six weeks prior to sale ofgoats

If goats are at risk of becoming infectedwithin this period and drenching is deemednecessary, care should be taken with respectto the WHP and ESI. Only registeredproducts should be used to avoid residues inmeat product. Read labels on drenchcontainers and keep accurate records.

If drenches are inefficient due to drenchresistance or because the larval challengefrom the pasture is high, stock rotationsthrough browse paddocks becomeparticularly important.

Caprimec® is the first product registered forgoats that has a goat-specific WHP and ESI.When the BZ and Oralject® drenches wereregistered for goats the WHP and the ESIwere inferred from sheep but only for someBZ drenches. See Module 9 – Parasitecontrol Toolkit 9 page 5.

Managing drench resistance

Drench resistance develops from 2 mainsources – it can be developed on–farmthrough ineffective drenching and throughfrequent use of drenches at suboptimal doserates particularly in dry weather or by beingimported onto property with purchased oragisted goats.

Strategies to counteract drench resistanceinclude:

• Use feed withdrawal at drenching

Withdrawing feed 24 hours before and 12

hours after drenching will extend theuseful activity of the BZ and abamectindrenches, with concomitant increases inefficacy against resistant strains ofworms. Do not withdraw feed if using theNeguvon drench. Ensure access to waterat all times.

• Use grazing strategies to stabilise drenchresistance

Stock should be treated with registereddrenches and left on a low-worm longpasture or a browse paddock. Asreinfection may occur very quickly a moveto the low-worm long pasture or browsepaddock a few days prior to drenching isadvocated. The time interval in the newpaddock before treatment can be variedin relation to the estimated levels ofinfection carried by the animals at thetime of the move.

• Follow with paddock rotations

Paddock rotation of goats either at shortinterval for barber’s pole or at longerintervals for black scour worm has beensuccessful on many properties.

In the tropics and subtropical zones,infective larvae of barber’s pole arepresent on pasture about 4 days after eggdeposition and fall to barely detectablelevels within 4–6 weeks. A grazing systemutilising 10 paddocks, each one grazedfor 3.5 days and then spelled for 31.5days, reduced egg counts of goats to lessthan half those of similar goatsset–stocked on an adjacent area. Therotation cycle was 35 days. For blackscour worm, longer rotation intervals tocompensate for the longer survival timeson paddock, perhaps up to 60 days, arerecommended but need to be tailored forthe location. Consult with yourveterinary advisor.



Hints for effective drenching

• Know the capacity of registered drenchesto kill worms on your property byconducting a drench–screen – check withyour local veterinary laboratory for details.

• Use drenches at the correct dose rate.

• Check the accuracy of the drenching gun.Set the gun at the required dose rate (eg.2ml), make five squirts into a medicineglass and the level should be five timesthe dose rate eg. 10ml. If not, adjust thegun until it is delivering an accurate dose.

• Dose to the heaviest in the group. Ifbodyweights vary throughout the herdseparate goats in weight groups and doseto the heaviest in each group.

• Administer drugs effectively. Make surethat the dose is given at the back of themouth as a firm squirt. If the dose isplaced at the front of the mouth it will bedirected to the abomasum and not to therumen.

• Always drench in a race. Goats shouldbe standing properly in the race so thatthe dose can be swallowed quickly andthe tube to the gun doesn’t suck in airfrom the pack. This occurs when theoperator’s head is down and the pack isinverted. Don’t miss any animals.

• Check contraindications. Check labels foradvice. Most products are very safe.

Guidelines for controlling lice andother external parasites on goats The most common external parasites ofgoats are lice, a number of species of mitesand, in some areas, ticks. Biting flies cancause problems from time to time, sheepnose bots may also infest goats andoccasionally animals can become fly struck.

Lice

Four species of lice, divided into chewingand sucking species, infest goats inAustralia. The chewing lice, Bovicola capraeand Bovicola limbatus, feed mainly on skinscurf, superficial skin cells and bacteria. B.caprae will infest all breeds of goats whereasB limbatus, the Angora goat chewing louse,is restricted mainly to Angora and crossbredgoats. Chewing lice irritate goats, causingthem to itch and rub against trees, fencesand other structures. This is particularlydamaging in fibre goats where lice candecrease the amount of mohair andcashmere produced and significantly reducethe quality and market value of the fibre.Infestations with chewing lice can also affectskin quality.

The sucking species (Linognathus stenopsis)and African blue louse (Linognathusafricanus) feed by penetrating capillaries withfinely adapted mouthparts and suckingblood. The common goat sucking louse L.stenopsis is found on most goat species andoften occurs in mixed infestations withchewing lice. The African blue louse was firstidentified in Australia in 1988 and is probablynot widespread.

Sucking lice can reduce weight gains andcause anaemia when present in highnumbers. The formation of scabby bleedingareas, stunting of weaned goats andoccasionally death in heavily infested kidshas been reported however heavyinfestations generally only develop whengoats are in ill health or under stress.

Detecting infestations

The most common indication of lice is theobservation of goats rubbing, scratching orbiting themselves. Many other things canhowever cause goats to itch so it isimportant to actually see lice to diagnose aninfestation.

Lice can be found on most parts of the body,although largest numbers are generally foundin areas with long fibre.

Chewing lice and sucking lice look quitedifferent. Chewing lice have a broad brownhead and a pale brown body with darkbands. The young lice (nymphs) are smallerwith a cream coloured body and a brownhead, but no bands. Sucking lice tend to belarger than chewing lice with a narrow headand much wider dark brown body. Theysometimes appear almost bluish in colourbecause of blood ingested during feeding.

Controlling lice

There are two main elements of good licecontrol in goats – preventing new infestationsand effective treatment when infestationsoccur.

Preventing new infestations

In Australia goat lice appear to be specific togoats and do not generally breed on otheranimals or birds. Most new infestations resultfrom contact with other infested goats,although often a supposed new infestationwill have come from failure to completelyeradicate lice at a previous treatment.

Goats carrying lice come from three mainsources;

• newly purchased animals,

• strays or feral goats and

• goats that were missed at last treatment.

Infestations beginning from contact withother infested goats at shows or field dayshave also been reported. Developingstrategies to minimise the chance of newinfestations from these sources will do muchto reduce the need for treatment and preventlosses from lice.

Although goat lice have been collected fromsheep overseas, studies in Australia showedthat chewing lice did not transfer from goatsto sheep held in close contact for 8 weeksand that although sucking lice transferredfrom goats to lambs run with them, they didnot persist on the lambs beyond 12 days.Therefore it is unlikely that other animals willbe a source of new infestations. However,other animals paddocked in close contactwith goats could carry goat lice for shortperiods and should be either removed fromthe goat herd when lice treatments areapplied or treated at the same time.

In intensively managed or housed goatsthere is also the chance of reinfestation fromcontaminated facilities if animals are treatedwith a non residual treatment and returned toareas where lice or lice eggs have beendislodged. Although the likelihood ofinfestation from contaminated facilities isvery low, a period of 2 weeks exclusion forchewing lice and 3 weeks for sucking lice willremove any risk.

Treatment for lice

Sometimes goats carry only low numbers oflice that cause little problem. This isparticularly so with short haired breeds. Inaddition, lice numbers tend to increaseduring autumn and winter but then fall awayin summer. As needless treatment increasesselection for resistance and can leaveresidues in product, it is important toconsider whether the lice are causing anydistress to goats or are likely to causeeconomic loss before deciding to treat. If youcannot detect an infestation treatment is notwarranted

Animals with long hair in winter and understress from disease or poor nutrition tendto develop the heaviest infestations.


Methods of pesticide application available forgoats include backline application, sprayingand dusts. Products currently registered fortreating lice in goats are shown in Module 9– Parasite control Toolkit 9 page 6.

Backline application

One product, Clout-S, which contains thesynthetic pyrethroid deltamethrin, isregistered for control of lice in goats. Incontrast to sheep, it is not necessary toshear goats before the application of Clout-S, however better effect is likely with Angoragoats if they are shorn before treatment.

To gain good effect from backline treatmentthere are a few key rules that should befollowed.

• Set dose rate for the heaviest goat in thegroup, according to label instructions.

• Use the correct application gun andensure that it is delivering the requireddose. This can be done with a smallmeasuring cylinder or perhaps a medicineglass.

• The application strip should be along themiddle of the back all of the way from thetop of the head to the tail

• Avoid operator contact. If othermanagement procedures are beingconducted, apply lousicide last

Spraying

To obtain good lice control from sprayinggoats, it is important to ensure that the hair isthoroughly wet to the skin and that goodcoverage of the whole body is achieved. Acoarse spray is most effective at wettinggoats and reduces the likelihood ofinhalation.

Dusts

Sprinkle lightly over the whole body andwork into the skin. As rotenone and sulphurare the active ingredients in the onlyregistered dusts for goats and have littleresidual effect, repeat treatments will berequired to achieve eradication.

Dipping

No lice control chemicals are registered inAustralia for application to goats by dipping.

Key rules for effective and safe use oflouse control products.

• Apply treatments thoroughly and strictlyaccording to label instructions. Toeradicate lice, all lice on each animal mustcome into contact with the lousicideapplied. Lice can occur on most parts ofthe body.

• All animals on the property must betreated at a similar time. Even animalswithout lice clearly visible should betreated. If this is not done, once theprotective effect of treatment has wornoff, undetected lice on the untreatedgoats can spread back to the treatedanimals. If different groups of goats aretreated at different times this can set up acycle of reinfestation. Remember thatbucks and kids can be a source of liceand should also be treated.

• Remember louse eggs. Most lousicidesdo not kill eggs. Eggs can take up to 10days to hatch and the hatching nymphscan start a new infestation. It is importantto establish if the treatment you are usingprovides residual effect for this periodand, if not, to apply a second treatmentapproximately 2 weeks after the first.


• If possible, avoid treating goats in dampweather or where rain is expected within24 hours.

• Consult the restrictions for use andwithholding periods. The meatwithholding periods for productsregistered for application to goats aregiven in Table 1. Most products shouldnot be used on lactating animals or wheremilk or milk products may be used forhuman consumption. Remember that it isillegal to use a product not registered forthis use.

• Wear appropriate protective clothing andfollow safety directions and indications foravoiding environmental impacts as statedon the label. Lousicides are toxicproducts and some products have beenwithdrawn from use on other speciesbecause of concerns about operatorsafety.

• Consult your veterinarian if controlattempts are unsuccessful.

Ticks

A number of species of ticks are found ongoats although they are seldom a majorproblem. The main species in Australiainclude;

• the paralysis tick Ixodes holocyclus (alsocommonly called the scrub tick or dogtick),

• the ‘Australian’ cattle tick (Rhipicephalus[Boophilus] microplus) and

• the New Zealand cattle tick(Haemaphysalis longicornis).

The brown dog tick Rhipicephalussanguineus and various other species ofnative ticks are also occasionally recoveredfrom goats. I. holocyclus is the main speciesof concern as it may cause posteriorparalysis in young goats however affectedgoats usually recover.

I. holocyclus paralysis toxin anti-serum ishowever available under prescription asPurified Anti-tick Serum (SummerlandSerums Pty Ltd, Astonville NSW) and isregistered for treating I. holocyclus inducedparalysis in goats.

Products registered for controlling ticks areshown in Module 9 – Parasite control Toolkit9 page 6. These include mixtures ofcypermethrin and chlorfenvinphos andformulations of amitraz. The latter are onlyregistered in NSW although a permitcurrently also exists for their use, undersupervision of QDPI&F, in Queensland. Whentreating for ticks, it is especially important toensure that all parts of the animal, includingthe belly, inside legs and ears, are wet.

Mites

A number of mite species are known to infestgoats but seldom cause significant problems.The main species are;

• the ear mites Psoroptes cuniculi andRaillietia caprae,

• the follicle mite Demodex caprae and

• the mange mite Chorioptes bovis.

In most cases mite infestations cause littleobvious effect but sometimes, in young orold, diseased or stressed animals, lesionscan spread and become more debilitating.

Ear twitching, scratching of the ears andhead shaking are common signs of ear mitesand sometimes, with close inspection, themites, which are about 1mm long, can beseen in the ear canal. Breeds with hangingears (such as Anglo Nubian) appear moresusceptible to ear mites than goats witherect ears.


Chorioptic mange mites are found mostcommonly on the coronet, udder, scrotumand limbs of goats and may cause crusts or‘scabs’ of yellowish exudate that can rangein thickness from a few millimetres to severalcentimetres in thickness.

Demodex mites are highly specialised mitesthat live in the follicles and sebaceous glandsand sometimes form papules or nodules onthe head, neck, shoulders and flanks ofgoats.

No products are registered for treating mitesin goats and, where lesions have becomeextensive or infestations are thought to becausing distress to goats, veterinary adviceshould be sought.

Biting flies and fleas

Stable flies, bush flies, mosquitoes, bitingmidges, March flies, sand flies, black fliesand buffalo flies can all attack goats and maycause problems with goats if the numbersbecome too high. High numbers of bitingflies can produce large sores on the legs,face, ears, udder and scrotum of goats andcan cause reductions in weight gains. Bushflies (Musca vetustissima) can annoy goatsby feeding around the eyes and are known totransmit eye diseases such as pink eye inother species.

Fleas can also infest housed goats but areunlikely to be a problem in paddock runanimals.

Barricade S and Blockade S are registeredfor control of buffalo fly in goats (Module 9 –Parasite control Toolkit 9 page 6).

Flystrike

Goats can occasionally also becomeflystruck in wounds, particularly fightingwounds in bucks, and where goats becomefouled with urine or faeces although this isseldom a significant problem. There are anumber of products containing diazinon andsynergised pyrethrins registered for treatingfly strikes in goats (Module 9 – Parasitecontrol Toolkit 9 page 6).

Nose Bots

Nose bot flies deposits small larvae, about1mm long, in the nostrils of the goat. Thelarvae then move into the nasal passagesand frontal sinuses where they complete theirdevelopment. When sneezed out by the goatthey may be up to 2cm in length.

The flies are most active in the warmermonths and may disturb sheep or goats intheir efforts to deposit their larvae. This caninterfere with grazing and animals underattack are often seen bunched together withtheir heads pushed into the flanks of otheranimals or close to the ground. Nose botsoften cause mucus discharge from thenostrils of goats and can cause frequentsneezing.

There is only limited information available onextent of infestation of goats in Australia andin most cases they cause little economicimpact. Treatment is rarely necessary and, asthere are no products registered for use ingoats, should only be carried out only underveterinary instructions.


Tool 9.1 Finding further information

Tool 9.2 Glossary of terms

Tool 9.3 Commercially available anthelmintics registered for nematode control in goats

Tool 9.4 Insecticides and acaracides registered for ectoparasite control in goats

Case studiesThe organic option

David and Mary Booth (page 7)

Drench rarely and rotate

Max and Sandra Strong (page 9)

Toolkit 9 – Parasite control

Module 9 – Parasite control Toolkit 9 1

2 Module 9 – Parasite control Toolkit 9

Tool 9.1

Finding further information

Options for the control of parasites in theAustralian goat industry, MLA, 2007 (FULLREFERENCE REQUIRED).

Module 6 – Husbandry Toolkit 6 page 3Common health problems

Module 7 - Nutrition

Websites

www.wormboss.com.au

http://www2.dpi.qld.gov.au/sheep/4720.html

Tool 9.2

Glossary of terms

Body Condition Scoring

Body condition scoring is a field basedmethod of scoring the tissue over thelumbar vertebrae of goats. The winter scourworms such as Trichostrongylus spp. andTeladorsagia sp. cause reduced appetite,scouring and rapid weight loss that is easilydetected by this method. Scour worms donot cause anaemia.

Export Slaughter Interval

An Export Slaughter Interval (ESI) is the timethat should elapse between administrationof a veterinary chemical to animals and theirslaughter for export. ESIs managedifferences between Maximum ResidueLimits allowed for chemicals in Australia andits trading partners. ESI advice isparticularly important for quality assuranceschemes, and especially for producers fillingout the National Vendor Declaration (NVD)forms as part of the whole-of-chainmanagement of exported product. ESIshave been agreed to by the industry and theregistrant of the veterinary chemical.

Eyelid Colour Scoring

Eyelid Colour Scoring is a field basedmethod of scoring the colour of theconjunctiva (the lower inner eyelid) ofindividual goats against a simple colourchart to grade the degree of anaemia.Anaemia is associated with blood suckingnematodes such as Haemonchus contortus(barber’s pole worm) but also has othercauses. This method is used to detectaffected sheep and goats for treatment andculling. Red is healthy, pink is moderatelevel anaemia and a trigger to drench whilewhite is very anaemic.

Off-label use

An off-label use of a chemical product isuse of the product in a way that is notcovered by an instruction on the labelapproved by APVMA for the productregistered in Australia.

Refugia

Refugia is the name given to that proportionof a given parasite population that escapesexposure to an anthelmintic and allows thesurvival of anthelmintic-susceptibleparasites. This part of the parasitepopulation is usually the free living stageson pasture but can also be worms inuntreated animals or even inhibited larvaewithin the host.

There are 2 sub-populations that constitutethe parasite population at any one time.One sub-population is in the host asdeveloping and mature adult worms and theother subpopulation is on pasture as eggs,larvae and free living infective larvae. Duringhot dry summers, the numbers of free livingstages on pasture (refugia) may be very lowwith most of the parasite population in thehost. The reverse is true of wet summers,especially for barber’s pole worm with mostof the parasite population as larvae onpasture.

Drenching when very few worms are inrefugia (the timing of this will vary with thetype of climate, whether Mediterranean,winter rainfall or summer rainfall) will heavilyselect for drench resistance. The progeny ofsurvivors of the drench will have littlecompetition from the few larvae on pasture.When numbers in refugia are high, theprogeny of the survivors of the drench willoften be swamped by the high numbers oflarvae on pasture and selection forresistance will take longer to occur.



Registered chemical

Before agricultural and veterinary chemicalproducts can be sold, supplied, distributedor used in Australia, they should beregistered by the APVMA. The registrationprocess is governed by Commonwealthlegislation and each chemical productundergoes rigorous scientific assessmentbefore its registration can be approved. TheAPVMA allocates a unique registrationnumber which is printed on the bottom ofthe product label.

Unregistered chemical

An unregistered chemical active constituentor chemical product is one that has notbeen assessed and registered in Australiaby APVMA.

Withholding period

The withholding period (WHP) is theminimum period which must elapsebetween last administration or application ofa veterinary chemical product, includingtreated feed, and the slaughter, collection,harvesting or use of the animal commodityfor human consumption. WHPs aremandatory for domestic slaughter and onthe label of every registered product.


Tool 9.3

Commercially available anthelmintics registered for nematodecontrol in goats

Parasite

Nematodes, large lungworm,tapeworm and liver fluke (aidin the control of adult fluke)

Nematodes,large lungwormand tapeworm

Nematodes

Nematodes,large lungworm

Baber’s pole only

Active group

BZ

BZ

BZ

BZ

BZ

BZ

BZ

Morantel citrate

MacrocyclicLactone

Organophospha

Constituent

albendazole*(19g/L)

albendazole*(19g/L)

albendazole*(19mg/mL)

fenbendazole‡(25g/L)

fenbendazol‡(25g/L)

fenbendazole‡(25g/L)

oxfendazole*(45.3g/L)

morantel citrate*(30mg/mL)

abamectin''(0.8mg/mL)

trichlorfon§800mg/kg

Brand name

Alben

Albendazole (Sheep,Lamb & Goat)

Valbazen SheepLamb & Goat Drench

Fenbendazole

Fenbendazole

Panacur 25

Oxfen LV

Oralject Goat &Sheep Wormer

Caprimec

Neguvon

Manufacture

Virbac

WSD

Coopers

4Farmers

WSD

Virbac

Virbac

Virbac

Virbac

APVMApermitPER9864

WHPmeat(days)

10

10

10

14

14

14

10

7

14

7

ESI (days)

10 (inferred)

Not set

Not set

Not set

Not set

Not set

14 (inferred)

Not set

28

Not set

* Not to be used in goats producing milk for human consumption or processing.† Kids fed this milk should not be slaughtered for human consumption within seven days.‡ Fenbendazole is registered for use in lactating does whose milk is to be used for human consumption. Milk withholding period is 24 hours. § Not to be milked for at least 28 days after treatment.|| Caprimec is registered as of August 2007. The withholding period for milk is four days.


Tool 9.3

Commercially available anthelmintics registered for nematodecontrol in goats

Parasite

Liver fluke(immature and adults)

Active group

BZ

BZ

BZ

BZ

BZ

BZ

Constituent

triclabendazole*†(100g/L)





triclabendazole*†(50g/L)+Se assod.selenate(0.5g/L)

Brand name

Exifluke OralFlukicide

Fasinex 100 Oral

LV TriclabendazoleFlukicide

Flukguard S

Tricla 50

Flukare S WithSelenium

Manufacture

Bomac

Novartis

WSD

Norbrook

Youngs

Virbac

WHPmeat(days)

21

21

21

21

21

21

ESI (days)

Not set

Not set

Not set

Not set

Not set

63 (inferred)

* Not to be used in goats producing milk for human consumption or processing.† Kids fed this milk should not be slaughtered for human consumption within seven days.‡ Fenbendazole is registered for use in lactating does whose milk is to be used for human consumption. Milk withholding period is 24 hours. § Not to be milked for at least 28 days after treatment.|| Caprimec is registered as of August 2007. The withholding period for milk is four days.

Module 9 – Parasite control 77 Module 9 – Parasite control Toolkit 9

Tool 9.4

Insecticides and acaracides registered for ectoparasite control ingoats

Parasite

Lice

Ticks

Mites

Nasal bot

Flystrike

Active group

SP

OP

OP

OP

Botanical/inorganic

OP/SP

OP/SP

Formamidine

Formamidine

Formamidine

Formamidine

OP/others

OP/others

OP/others

Constituent

Deltamethrin

Diazinon

Diazinon

Diazinon

Rotenone &sulphur

Cypermethrin &chlorfenvinphos


Amitraz

Amitraz

Amitraz

Amitraz

Diazinon &pyrethrins & PBO



Brand name

Clout-S*

Nucidol 200EC

Di-Jet†

WSD Diazinon‡

Inca PesteneInsect Powder§

Blockade S*

Barricade S*

Tacktic EC''

Tacktic WP''#

Amitik#

Amitik EC#

Nil

Nil

WSD Flystrike*Powder

WSD Mulesing*powder

Flystrike powder

Application

Backline

Spray

Spray

Spray

Dust

Dip

Dip

Spray

Dip/spray

Dip/spray

Spray

Dust

Dust

Dust

WHPmeat(days)

3

14

14

14

1

8

Not set

Nil

Nil

Nil

Nil

14

14

14

Manufacturer

Coopers

Novartis

Coopers

WSD

INCA

Coopers

Fort Dodge

Intervet

Intervet

Coopers

Coopers

WSD

WSD

Coopers

* Do not use on female goats which are producing or may in the future produce milk or milk products for human consumption.† Milk taken from goats within 48 hours following treatment must not be used for human consumption or processing.‡ Milk collected from does with 48 hours following treatment must not be used for human consumption or processing. This milk should not be fed to kids.§ Do not use on lactating does where milk or milk products may be used for human consumption.|| NSW only; however, a permit currently exists for use in Qld but only under the supervision of DPI&F.# Milk WHP nil.


Tool 9.4

Insecticides and acaracides registered for ectoparasite control ingoats

Parasite

Buffalo flies

Fleas

Active group

OP/SP

OP/SP

Constituent



Brand name

Barricade S*

Blockade*

Nil

Application

Dip

Dip

WHPmeat(days)

8

8

Manufacturer

Fort Dodge

Coopers

* Do not use on female goats which are producing or may in the future produce milk or milk products for human consumption.† Milk taken from goats within 48 hours following treatment must not be used for human consumption or processing.‡ Milk collected from does with 48 hours following treatment must not be used for human consumption or processing. This milk should not be fed to kids.§ Do not use on lactating does where milk or milk products may be used for human consumption.|| NSW only; however, a permit currently exists for use in Qld but only under the supervision of DPI&F.# Milk WHP nil.

Case studyTHE ORGANIC OPTION

NAME: David and Mary Booth

TRADING NAME: Buronga Organics

PROPERTY NAME: Buronga

PROPERTY LOCATION: Cootamundra, New South Wales

PROPERTY SIZE: 1,600ha

NUMBER OF GOATS: 800 breeding does

RAINFALL: 600mm (winter dominant)

MAIN GOAT ENTERPRISE: Domestic meat production

TARGET MARKET: Chevon. Direct to butchers, specialty markets includingorganics, farmers markets, and restaurants

SECOND GOAT ENTERPRISE: Value-adding – leather and goatmeat jerky

TARGET MARKET: Farmers markets and direct to consumer

OTHER FARM ENTERPRISES: Organic meat sheep based on Dorper and White Dorper,organic beef based on Angus and Welsh Black andorganic spelt cropping

David and Mary Booth operate an organically certified mixed grazing and cropping enterprisein southern NSW. Organic certification necessitates a chemical free production environmentand reinforces the importance of preventative management to minimise the impact ofparasites on production.

The Booths consider three key factors in managing the risk posed by internal parasites;

• bulk of pasture and dry matter,

• nutrition and

• body condition.

Throughout the year, goats are, wherever possible, strategically grazed to be allowed accessto browse. This is particularly important during winter when the worm risk is highest and thethreat posed by cold wet weather is greatest. Special paddocks with ample browse and goodshelter are used during this period to maintain the goats in optimal nutritional condition so theycan sustain a natural immune response to worm infestation.

During other times of the year the goats are allowed to graze more open pasture howeverpasture length is maintained by managing animal numbers. Destocking occurs when feed isscarce.



Goats are strategically grazed in a rotation with sheep and cattle to minimise the risk of crosscontamination between sheep and goats. Cattle play an important role in cleaning uppotentially infective larvae on pastures and are grazed with goats and between sheep andgoats in a rotation. Whenever possible the Booths avoid grazing goats in close proximity tosheep when pastures are short as this has been identified as a key cause of infection.

The Booths believe that a manageable worm burden is normal to goats and it is only whenthis impacts animal health and production that worms become a problem. The provision ofadequate nutrition to support the goat’s natural immune response to worms is important.Supplementary feeding and strategic destocking to meet feed supply are used to maintainnutrition. Attention to nutrition is considered particularly important in the lead up to and duringperiods of peak demand, such as lactation, and pastures are monitored regularly at suchtimes.

Throughout the production cycle, the Booths identify animals that appear to be moresusceptible to internal parasites and cull these as a matter of principle. These animals may bein poorer condition than the herd average, have a rough coat or just generally lack bloom.Such animals are sold into the export meat market. This is important in building the overallresistance of the herd to worms and the sustainability of the goat enterprise in the long term.

Veterinary advice is sort whenever intervention is required and faecal egg count tests havebeen used in the past to identify potential problems. When a problem has been identified thishas been dealt with according to veterinary advice and the requirements of internationalorganic certification.

David commented that; “At the end of the day it comes down to those three critical elements;classing on body condition and taking the tail out of the mob, providing browse as much as ispossible and maintaining pasture length and supplying adequate nutrition to allow the goatsimmune system to fight internal parasites naturally.”


Case studyDRENCH RARELY AND ROTATE

NAME: Max and Sandra Strong

TRADING NAME: GM and SJ Strong

PROPERTY NAME: Mountain View

PROPERTY LOCATION: Gunnedah, NSW

PROPERTY SIZE: 420ha

NUMBER OF GOATS: 100 stud Boer goats 120 cross bred

RAINFALL: 600mm

MAIN GOAT ENTERPRISE: Live export stud breeder

TARGET MARKET: Malaysia breeder market

SECOND GOAT ENTERPRISE: Domestic meat

TARGET MARKET: Capretto, Sydney

OTHER FARM ENTERPRISES: Dorper studMeat sheep production Cattle, Angus x Wagyu breeding operation

Max and Sandra run a mixed grazing operation in the Gunnedah region of NSW. The goatoperation involves a Boer goat stud breeding enterprise targeting the live export market aswell as a domestic meat market focussed cross breeding operation.

The Strongs endeavour to minimise the impact both internal and external parasites have ontheir operation through preventative management strategies such as grazing management,moderate stocking and the provision of adequate nutrition including mineral licks. The crossbreeding enterprise rarely requires intervention as the goats are grazed in low densities androtated through clean paddocks where browse is often on offer.

Historically all animals brought in are drenched with a registered drench or according toveterinary advice on arrival and kept isolated for a three week period before being introducedto the herd.

Due to higher densities and the need for more intensive management, internal parasiteproblems are occasionally encountered in the stud enterprise. Problems are identified throughvisual assessment and treated on a needs basis. Livestock are not treated unless symptomssuch as scouring or a loss of body condition are detected. Max Strong indicated that thisusually only occurs prior to kidding in the does. Drenching is rarely required more that once ayear and drenches are rotated over consecutive years to minimise the development ofresistance.

Lice rarely present a problem however on the one occasion that they did, Clout-S was used. Apoor initial result necessitated veterinary consultation. In this instance it was found that twoapplications at a ten day interval, dosing to the heaviest animal, achieved total erradication.*

The Strongs are currently implementing a fencing program to allow the goats to bestrategically grazed with cattle to better manage the internal parasite risk. This combined witha faecal egg count testing program and visual assessment will further reduce the need forchemicals.


* This is not intended as a recommendation. A vet should be consulted as required.

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