Goats can potentially suffer from a number of parasites that are
broadly characterised as "Ectoparasites"
such as mange and lice that live on the body surface and
"Endoparasites" such as worms that live
inside the body.
Goat endoparasites include:
- Nematodes (Helminths) - roundworms.
These are by far the most important endoparasites of the goat,
the majority of which live in the stomach and gut (Fig 1), but also
include lungworms that complete their life cycle in the respiratory
tract. A number of species are shared with cattle and sheep
(important to bear in mind when devising a worm control programme
if you have shared grazing). They belong to the genera
Ostertagia (Telodorsagia), Cooperia,
Nematodirus, Oesophagostomum and Trichostrongylus
Fig 1: Nematode worms in the gut of a goat at
With the exception of Haemonchus the main presenting
signs in a goat with gut roundworm infestation are diarrhoea and
weight loss. Haemonchus contortus (Barbers
Pole worm) however spends most of its time in the 4th
stomach (abomasum) where it sucks blood, resulting in anaemia (Fig
2) and weight loss, diarrhoea is not a feature - an important point
Fig 2: Haemonchus resulting in severe anaemia
(note conjunctival colour).
One of the reasons that nematodes are so important in goats is
that unlike cattle and sheep, they have evolved in such a way that
they produce very poor immunity on exposure, and thus remain
susceptible to re-infection throughout their lives and worm control
therefore remains a constant priority.
To fully understand the basics of worm control in goats, we have
to appreciate the parasite life cycle.
We know that it takes between 16 and 21 days after a goat has
picked up infective larvae from the pasture, before worm eggs will
appear in the faeces - this we can predict. Far less
predictable however is the time taken for the development of
infective larvae (L3) that hatch from eggs passed in faeces on the
pasture. This will vary depending on a number of factors
including weather conditions, with rapid development (as little as
2 weeks) in warm damp weather, and slow development (many weeks or
even months) in hot dry or very cold weather.
It follows therefore that it is impossible for your vet to give
you specific guidance as to when is the best time to worm your
goats - or even if they need to be wormed at all? It is for
this reason that most large commercial goat units house their goats
all year round - it keeps them away from pasture, and hence from
the risk of developing a worm problem (Fig 3).
Fig 3: Goats housed permanently no worm
The concept of monitoring for worms in your goats is one to
embrace - worming when they do not need to be wormed wastes your
money and also encourages the development of wormer
resistance. You could wait until you see signs of diarrhoea /
weight loss and then worm, but you run the risk of them developing
severe gut damage if left untreated, and the diarrhoea and weight
loss could be due to other causes such as fluke.
A relatively cost effective approach to monitoring your goats
for worms is based on the examination of faeces samples, either
individual samples, or pools of up to 10 faeces submitted to the
laboratory as individual samples (then pooled in the
laboratory). The number of eggs counted gives an indication
as to the weight of infection - and the likelihood that worming
would be beneficial. Discuss this approach with your vet, and
in particular the interpretation of any results obtained.
There are do it yourself egg counting kits available, but you must
only attempt this if you have been trained in how to undertake and
interpret the results (Fig 4).
Fig 4: Worm eggs under a
There are no wormers that are licensed for goats in the UK (i.e.
have a marketing authorisation for use in the species) - and your
vet will generally advise the use of a wormer licensed for use in
other species (usually sheep), under a principle referred to as
cascade. Remember that there are essentially 3 groups of
wormer to which the vast majority of currently available wormers
belong these are the Benzimidazole Group, The Levamisole Group,
Avermectin / Milbemycin Group. There are also two relatively
new products that are available only through your vet, and these
should only be used where there is a known wormer resistance
problem, these "new products" are "Zolvix (monepantel) and Startect
(derquantel and abamectin). There is evidence to suggest that the
Benzimidazole, Avermectin and Milbemycin Groups require a doubling
of the sheep dose (in mg/kg), with around 1.5 times the sheep dose
(in mg/kg) for Levamisole - although particular care must be taken
not to overdose with this product as it can be toxic. Goats
are heavier than they look, so always ensure you dose to an
accurate goat weight, dose to the heaviest in the group (not the
average weight), and get your calculations correct and finally make
sure your dosing equipment delivers the correct dose. Any
factor that leads to underdosing can lead to wormer resistance.
If you suspect that your wormer is not working, ask your vet to
test for wormer resistance. Also ask your vet to prepare a
wormer protocol as part of your goat health plan. The on-line
manual "Sustainable Control of Parasites in Sheep - SCOPS" gives
further information, much of which is very relevant to goat
Also discuss with your vet how to ensure that you don't bring in
resistant worms to your premises when you buy goats, or have new
goats arriving and mixing with your own goats for whatever
reason. Such an approach should be based on the currently
available principles for sheep described in the SCOPS manual.
Remember it is not the goat that becomes resistant to the wormer,
but the worm burden it may be carrying - hence the need to ensure
that a resistant burden is not deposited on your pasture - thus
becoming available to your goats. Such an approach is
referred to as "quarantine dosing."
These are segmented flat (and often very long
worms) that may live in the gut of your goat; the main species in
the UK is Moniezia. Unlike nematode worms in which worm eggs
and most larvae in faeces are invisible to the naked eye, large
tapeworm segments, (literally fragments that break off the end of
the tapeworm) can appear in the faeces (often wriggling) and be a
real cause for concern (Fig 5). Although unpleasant to see,
the worms in the gut actually cause very little if any harm to your
Fig 5: A Moniezia tapeworm, fragments
may break off and be found in faeces.
LIVER FLUKE (FASCIOLA HEPATICA):
This endoparasite disease of the liver is not common, but when
present on a farm can cause severe illness and death. Its
life cycle is long (8 - 12 weeks to complete), and involves a small
mud snail (Fig 6) measuring only 2 - 3 mm in length (Galba
truncatula), through which the free-living developmental stage
of the parasite must pass to complete the life cycle. It
follows therefore that the condition only appears on those premises
with wet / moist habitats where the snail can survive - this could
for example be the margins of a pond / stream, or even a leaking
Fig 6: Galba truncatula the mud snail
In acute fluke goats may simply be found dead as the immature
parasite literally bores its way in through the liver capsule,
causing haemorrhage as it does so, profound anaemia is a feature of
survivors. Goats that survive this initial insult will lose
weight, develop diarrhoea, and often develop a fluid filled
swelling under the jaw (so called "bottle jaw"), as the
mature fluke become established in the gall bladder (Fig 7) and
bile ducts causing liver dysfunction. Control is based on
identifying wet potential snail habitats on the farm and avoiding
them, and on farms with a known annual problem - using a strategic
flukicide control programme. There are no licensed flukicides
available for goats in the UK - consult your vet on the best
Fig 7: Fluke in the gall bladder of a
goat at post mortem.
These are small single celled protozoal parasites that multiply
in the wall of the gut, and can cause severe gut damage as a
result. Coccidiosis is caused by a parasite referred to as
Eimeria, and we recognise nine different species of
Eimeria in the UK, only two of which are capable of
causing severe disease namely E. ninakohlyakimovae and
E. caprina. Other species cause no illness at all, or only
mild signs - specialist tests can be used to differentiate the
Eimeria burden; relying merely on a total count can be
misleading. With protozoal diseases such as coccidiosis and
cryptosporidia we refer to the "egg" appearing in faeces as
an oocyst - a very resistant protozoal cystic form that can quickly
contaminate the environment.
At this point, it is important to remind the reader that
Eimeria are host specific - such that poultry coccidia
only affect poultry, cattle coccidia only affect cattle, and goat
coccidia only affect goats - unlike worms where many parasites are
shared with other species including sheep and cattle.
Infection is most commonly seen in young growing kids,
particularly if intensively reared. The parasite has a
massive multiplication potential, it is estimated for example that
for every single oocyst that is ingested, up to 1 million can be
excreted. Clinical signs can vary from sudden onset with
blood and mucous stained diarrhoea, straining to pass faeces and
abdominal pain in acute cases, to weight loss and pasty diarrhoea
in more chronic cases (Fig 8).
Fig 8: A young goat with coccidiosis,
note its dirty hind end and pot belly.
Control is based on attention to hygiene, specifically not
allowing infection to build up in young stock pens (faecal build up
encourages parasite build up with progressively heavier challenges
to youngsters in continual throughput systems). No products
are licensed for use in goats, but your veterinary surgeon may
advise the use of products licensed for use in sheep as
Another protozoan parasite (similar to Coccidia) that can affect
very young kids causing diarrhoea (Fig 9), which if severe can be
fatal, the same parasite can cause similar signs in both calves and
lambs - so be careful not to let it spread between the species if
confirmed. It is more commonly seen in kids that have not
taken sufficient colostrum (and are immunocompromised), in kids
where early artificial milk feeding is faulty or erratic, and as a
result of dirty feeding utensils or moving young kids into a
faecally soiled environment.
Fig 9: A kid with confirmed
There is a specific anti-cryptosporidial product available that
your vet may advise in a severely ill kid (although not licensed
for use in goats), but treatment is usually symptomatic, keeping
kids warm and dry, and ensuring they get sufficient fluids.
This organism is zoonotic - and can cause illness in humans,
particularly young children who can develop very severe
diarrhoea. It is always advisable to keep very young children
away from goat kids (and calves / lambs) that have diarrhoea; this
can be an extremely unpleasant experience in a very young