12943 - msa catalouge2

Controlling nematode parasites of
goats in pasture–based systems
Worms, or parasitic nematodes of the gastrointestinaltract, of goats are a major constraint to efficient Key benefits
production in pasture–based systems worldwide. Understand the importance of grazing management The overuse of chemicals to control worms in the sheep and cattle sectors has led to significant resistance issuesand anecdotal evidence suggests a similar situation Learn how to maximise the effectiveness of a The sustainable control of worms involves a dramatic reduction in chemical use and increased diligence inmonitoring for worm burdens, testing drenches forefficacy and incorporating browse and nutritionsupplementation as a minimum standard for better or hunched back with mucoid scours (nodule worm).
These changes in digestion can lead to inappetance,poor growth, a rough coat, weight loss, emaciation due Less reliance on chemical use is important in preserving to reduced appetite, scouring and sometimes death. those drench actives still giving good control.
Management of worms is as much about managementof drench resistance as it is about the worms Laboratory testing
themselves. Without a change in attitude towards
Laboratory testing can offer goat owners a number of drench usage, drenches currently effective are
tests to monitor the progress of infections over time unlikely to be so in a year or two.
and to determine worm populations and if drenching The integration of non-chemical control strategies with infrequent drenching is therefore imperative in achieving By the time the clinical symptoms above become the sustainable production of a residue–free product.
evident, productivity losses would have already
occurred. Laboratory worm egg count testing provides
Key nematodes
a method to monitor any rise of worm egg counts andallows clear decision making on the need to drench or The major nematode parasites of concern in goats are not to drench. The latter saves money on treatment and the barber’s pole worm (Haemonchus contortus) and the helps prevent or delay worm resistance.
small brown stomach worm (Teladorsagia [Ostertagia]circumcincta) that parasitise the abomasum. The scour Worm egg count and larval culture: It is standard
worms (Trichostrongylus spp.) are resident in the small practice within the ruminant industries to base decisions intestine and the nodule worm (Oesophagostomum to drench on the results of a worm egg count for the columbianum) is found mainly in the large intestine. numbers present and a larval culture to identify thetypes of worms present. Detecting infections
Drench resistance testing: A faecal worm egg count
resistance test (FECRT) is the standard to determine
Most of the clinical signs associated with worm drench usefulness in killing worms. Checking drenches infections are not highly specific but are generally for a change in the resistance pattern is recommended related to intestinal disturbances such as scouring (winter scour worms), constipation (barber’s pole worm) Your local state government or private veterinary without productivity losses and this attribute needs to be laboratory will assist with trial design and procedures for considered in the interpretation of worm egg counts. the FECRT and the drench–screen and will also provide Every time a goat owner picks up a drench gun they interpretation of worm egg counts specific to your location.
Controlling infections
The nematode cycle of constant infection and reinfectioncan be broken by preventing new infections and by Preventing new infections
When a chemical treatment is administered a few resistantworms are left in the goat because drenches are not 100% Reducing the size of new infections can be accomplished effective in all goats at all times. Their progeny then replace by reducing the intake of infective larvae from the pasture susceptible worms on pasture. In other words, a drench and strengthening the host’s ability to prevent becomes less effective every time it is used, albeit very establishment of these ingested larvae.
slowly initially. This rate of decline in efficacy is largelyinfluenced by the numbers of free–living parasite stages Reducing the intake of infective larvae: Goats are
on the pasture ie in refugia. In dry weather when few browsing animals and should have at least 30-50% of larvae are on pasture, heavy selection for drench resistance their food supplied as browse for optimal nutrition and takes place. Following on from this, utilise browse good worm control. Grazing lower than 10cm above the paddocks in dry weather rather than drenching.
ground exposes goats to larval parasites that congregatethere because of the greater moisture levels at the Managing drench resistance
soil–grass interface. Separation of the feed from larvalcontamination can be achieved through the provision of Drench resistance develops from two main sources – it browse. Browse does not necessarily mean trees.
can be developed on–farm from ineffective drenching and Browse plants, such as lucerne and other leguminous through frequent use of drenches at suboptimal dose crops in pasture–based systems, will supply extra nutrition rates particularly in dry weather or by being imported when pasture quality is poor, provide food free of larval onto property with purchased or agisted goats. contamination and contribute a moderate antiparasiticeffect due to their contained condensed tannins. Strategies to counteract drench resistance include:
Cattle grazed with goats will contribute strongly to better worm control and improvements in pasture quality. Goat Withdrawing feed 24 hours before and 12 hours after and cattle interchanges are based on host specificity.
drenching will extend the useful activity of the BZ and Goats share the same nematodes with sheep but only abamectin drenches, with concomitant increases in one with cattle. Adult cattle are resistant to nematode efficacy against resistant strains of worms. Do not infection and any larvae eaten while grazing will not withdraw feed if using the Neguvon drench. Ensure develop to adults. Attention must be paid to stocking rates however cattle can be grazed with goats or inrotation with them. Use grazing strategies to stabilise drench resistance.
Strengthening the overall immunity to worms:
Stock should be treated with registered drenches and Malnourished goats are particularly susceptible to left on a low-worm long pasture or a browse paddock. nematode infection. Extra nutrition in the form of protein, As reinfection may occur very quickly a move to the energy and minerals may be required during critical low-worm long pasture or browse paddock a few times. This typically occurs at weaning in kids and in does for about 2 weeks before and up to 8 weeks after kidding. During a moderate worm infestation, many goats appear Paddock rotation of goats either at short interval for unaffected while others seem to be severely affected.
barber’s pole or at longer intervals for black scour Identifying those goats less able to carry worm burdens worm has been successful on many properties.
without productivity losses and culling them will increasethe overall immunity of the herd to worms. Hints for effective drenching
Drenching nematode
Know the capacity of registered drenches to kill infections in goats
worms on your property by conducting a drench– screen–check with your local veterinary laboratory The need to treat existing burdens can be determined by worm egg counts and larval cultures. Strongly resilient Use drenches at the correct dose rate.
goats are however well able to carry worm burdens Check the accuracy of the drenching gun. Set the gun All chemicals should be used according to
at the required dose rate (eg. 2ml), make five squirts labelling requirements with particular attention
into a medicine glass and the level should be five to WHP and ESIs.
times the dose rate eg. 10ml. If not, adjust the gun Withholding period
until it is delivering an accurate dose.
The withholding period (WHP) is the minimum period Dose to the heaviest in the group. If bodyweights vary which must elapse between last administration or throughout the herd separate goats in weight groups application of a veterinary chemical product, including and dose to the heaviest in each group.
treated feed, and the slaughter, collection, harvesting or Administer drugs effectively. Make sure that the dose use of the animal commodity for human consumption.
is given at the back of the mouth as a firm squirt. If WHPs are mandatory for domestic slaughter and on the the dose is placed at the front of the mouth it will be directed to the abomasum and not to the rumen.
Export slaughter interval
Always drench in a race. Goats should be standing An export slaughter interval (ESI) is the time that should properly in the race so that the dose can be elapse between administration of a veterinary chemical to swallowed quickly and the tube to the gun doesn’t suck in air from the pack. This occurs when the operator’s head is down and the pack is inverted. Don’t miss any animals.
Always use registered chemicals and adhere to WHP and ESIs.
Commercially available anthelmintics registered for nematode control in goats Parasite
Active group
Constituent
Brand name
Manufacture
ESI (days)
Nematodes,
large lungworm,
tapeworm and
liver fluke (aid
in the control
of adult fluke)
Nematodes,
large lungworm
and tapeworm
Nematodes
Nematodes,
large lungworm
Baber’s
pole only
Liver fluke
(immature
and adults)
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.
Acknowledgements
Meat & Livestock Australia acknowledges the matchingfunds provided by the Australian Government to supportthe research and development detailed in this publication.
Further information
Tips & tools: Guidelines for controlling lice and otherexternal parasites on goats Going into Goats: Profitable producers’ best practice guide Level 1, 165 Walker StreetNorth Sydney NSW 2060 To find out about other MLA publications visit [email protected] or phone MLA on 1800 675 717.
Published October 2007 ISBN: 9781741911961 Meat & Livestock AustraliaABN 39 081 678 364 Care is taken to ensure the accuracy of the information contained in this publication. However MLA cannot accept responsibility for the accuracy or completeness ofthe information or opinions contained in the publication. You should make your own enquiries before making decisions concerning your interests.

Source: http://www.australianboergoat.com.au/admin/_files/articles/1318817769_internalparasitesingoats.pdf