Controlling nematode parasites of goats in pasture–based systems
Worms, or parasitic nematodes of the gastrointestinaltract, of goats are a major constraint to efficient
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
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
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 goatsParasite 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 goatsGoing into Goats: Profitable producers’ best practice guide
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Published October 2007 ISBN: 9781741911961 Meat & Livestock AustraliaABN 39 081 678 364
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